|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
sorry guys. I guess I didn't mention since I got the wastegate working correctly, it's only boosting about 3psi (or 4, may gauge my be off a little). I'm planning on upping it to 6-8psi. I'm surprised that when you didn't know I changed it from 15, you weren't urging me to set it a lot lower. Do you have any confidence in a stock engine at 15psi?
Maybe I don't understand? Air/fuel ratio is parts of air per part of fuel correct? Less parts of air per part of fuel (<14.7) is rich and more parts of air per part of fuel (>14.7) is lean. So me running 12-13 parts of air per unit fuel is rich whereas more parts of air per unit of fuel would be leaner. Is that not correct?
I wouldn't say it's very loud actually. Since all the sound is at the back now (besides the wastegate for the moment), it's actually pretty decent sounding until that wastegate opens.
This is where i need quite a bit of direction. How do you measure the amount of mechanical advance and total advance? Measuring initial timing is easy enough. Disconnect the vacuum advance and just use a normal timing light?
We're still trying to rebuild his front end so we can put the drivetrain in and get it mobile. But it shouldn't be too long. Maybe another couple months? I'm hoping to run my car down memphis drag strip soon.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
Sure you can run 15 PSi on a stock engine. I did not want to say anything about you running 15 psi, (your a big boy) I would run the suggested supporting equipment IE, intercooler, methanol injection & a J&S Safegaurd. http://www.jandssafeguard.com/Reason being, you are running stock cast pistons, they will explode w/medium to heavy detonation. 2800 RPM, 15 psi full boost, pretty good , glad we did not get the .96 A/R as suggested from, who was that? It's been so long since I checked how much timing a HEI dizzy can make,, but I remember it's a lot , more than what you need for total timing. Anyone remember how much mechanical advance an HEI dizzy has? I think he (Snowman) has an HEI dizzy? MBHD
12 port SDS EFI
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
"Sure you can run 15 PSi on a stock engine." I can't tell if that's sarcasm. As long as I kept it rich and stayed away from detonation, could I run 15psi? I understand those other things would make it safer but is it useable for a stock engine?
Yeah I have an HEI, I posted that on the supercharger thread in my list of parts just today.
But was I wrong about the air/fuel ratio? isn't <14.7 rich? isn't 12ish pretty rich at W.O.T.?
And what would I do to fix my extreme richness at idle? Do jets affect mixture at idle?
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Feb 2010
Posts: 136
Contributor
|
Contributor
Joined: Feb 2010
Posts: 136 |
Please correct me if I'm wrong, but you are suppose to tune (jet) to achieve 11-ish AFR at WOT. Then from there your can adjust your idle screws lean at idle. Also if your cruise is lean, so you are going from super lean to rich at boost, try putting a vent tube extension in. It will raise your cruise AFR. I am using a 8" one that richens up my cruise just right.
I am also running a HEI. I installed a lightweight advance kit from summit and after many combination's, the lightest springs worked the best. It allowed my rpm advance curve to ramp up quickly and max out about 20-25 degrees advance. (all-in) >> at idle 11 deg and by 1800-2000 rpm im at 25 deg. This is an estimate, I have no TACH. All measured with a dial back timing light.
Happy Boosting.
Snowman, good job.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
Snowman, it's not sarcasm. Thats is why I keep suggesting supporting items to do so.
My Syclone runs 14.7 PSI stock, w/cast pistons. I made the intercooler more efficient, added methanol injection, a J&S safegaurd & added more timing, did I mention I run 24 PSI of boost now? This is on a completely 100% stock longblock engine.
How many 15 PSI blasts did you do?
Also, you are not understanding how or what an intercooler & methanol injection does for an engine. I would suggest reading up on the two.
Yes, the higher the number, the leaner the A/F ratio.
12ish is not that rich on a boosted engine, I think you are reading up on naturally aspirated engine that 12.5 is about perfect A/F ratio @ W.O.T., not so for a boosted engine.
Do some more reading on A/F ratios on turbo engines.
Snowman, Boucher just did tuning on his Holley 2BBL carb, I would suggest asking him, how he did jeting changes & mods to his carb, he did it most recently.
MBHD
12 port SDS EFI
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
Thanks boucher. Sound like I need to get a dial back timing light.
So is it not a big deal that your syclone is a whole different engine? Is a cast piston a cast piston and detonation detonation? Just seems odd to compare these 60s engines to a 90s fuel injected v6 but what do I know?
I did about 10-12 15psi blasts. about 6 of them were at 14 degrees and 4 at 6 degrees (I didn't take off my vacuum advance but that's what they read at idle). The 14 degrees was scary fast and had crazy power. The 6 degrees was a slug and I had a bunch of problems like chugging, intake backfires, and just no power.
Hopefully I'm about to sell a computer and get the money to setup an intercooler and maybe start toward a alky/water setup.
I'm pretty confident that I understand what meth and an intercooler do. Methanol, when injected, raises octane of the charge and absorbs heat in the cylinder which allows for cooler temps. Water when mixed with meth has the same type of heat absorption without the benefit of octane boost. Intercooling cools off the compressed air charge because it gets hot when compressed. This gives the charge a cooler starting temperature in the cylinder. ^^^That's what I've gathered from what I've read.
Just read some and 12 is good for full boost. 13 is getting somewhat risky in case of some unknown something to make you run lean for a second.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
The main difference, w/the V-6 Syclone engine is that it is fuel injected (more even fuel distribution) & has a computer & will control knocking/detonation.
Your A/F ratios cylinder to cylinder will be off.
I would not recommend you going over the boost you were already seeing. I'll chime in later & type more.
BTW, how about some more pics of your downpipe & pipeing to the carb, bov, etc.
MBHD
12 port SDS EFI
|
|
|
|
Joined: Jan 2005
Posts: 2,123 Likes: 3
1000 Post Club
|
1000 Post Club
Joined: Jan 2005
Posts: 2,123 Likes: 3 |
If your cyl to cyl. distribution is off (which is practically any carbureted motor) you must have spark and mixture set up retarded and rich to protect the hottest, leanest chamber with the highest static CR. This kills power and mileage on the other 5.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
If you are still "on the cheap" theme you probably could install or possibly mod your vacuum can on the dizzy to retard timing when in boost. Need to read up on them. IIRC my friend says he can mod a stock type canister to give you boost retard? He is a Corvair expert & has access to the factory GM vacuum cans that retards the timing while in boost. He has tried several brand new NOS ones, used ones etc, on back to back tests & the amount of timing retard is all over the place. not consistant @ all. This way you could run more initial timing = better mileage, better turbo spool up, etc. Something like this but for your HEI. http://www.dalemfg.com/dale_018.htmhttp://www.american-pi.com/corvair/html/turbo.htmlPersonally,, I would just save up for a MSD BTM. If you are going to save up for any new mod, get a timing control devise first, intercooler set-up, methanol injection. Are you running 92 octane now or just 87 octane? I am wondering why you ask, (after the fact) if you can run 15 psi boost pressure on your stock engine after you had already done 12 or more WOT blasts. You already done so,,,, not safely mind you. I am really shocked your engine stayed together this long, w/you running 15 psi, A/F ratios being really lean, way too much total timing, running 88-89 octane (not even 92 octane) listening for detonation w/no downpipe connected to the turbo & no exhaust system. I have to say, you are probably one of the luckyiest guys I heard of just slapping the turbo on, no wide band on (initailly), way too much timing & running cheap gas, no intercooler etc. I am just saying, you are really lucky. Glad you did not blow it up,, you are not done by a long shot, just take your time & tune it, tune it, tune it! Snowman, BTW, how about some more pics of your downpipe & pipeing to the carb, bov, etc. MBHD
12 port SDS EFI
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
I'm probably just going to get the MSD BTM instead of doing the vacuum canister mod. Hopefully it'll be soon if scammers stop trying to buy my computer on ebay. >:-(
No. I'm running 93 now just to be safe. The first couples of times out, I ran 3/4 of a tank of 87 with a quart of octane booster. The can said it'd raise it 7 points so I guess that means it was almost 88? But I just filled a full tank of 93 and I'm already down to 3/4 of a tank after like 2 or 3 days. Please tell me that's because of how rich it is... :-(. I really need help tuning.
I don't understand why you keep saying I'm running lean. I watch my wideband like a hawk at full throttle pulls and it never gets higher than 13 most of the time. If it ever even touches 14.5 or 15 I let off. I need to change out that fuel pump which I'll do after work today. I also need to get a t-fitting so I can tap into my boost line going to my wastegate so I can run that to the fuel pump.
Since the wastegate I got didn't tell you which springs are which, I tried a different set of springs and now it boosts to 13 or 14psi *facepalm*. It actually doesn't do to bad like this though. I cant get into boost in 1st gear because I'm assuming since my rpms go up so fast, it pulls so much fuel that it drains the bowls because my A/Rs start fine at 12.5ish to 13 and then slowly lean out as the rpms rise. 2nd gear is usually fine though. It stays at 13ish until about 3000rpm until it starts leaning itself out. 3rd does the same thing as 2nd and starts leaning out about the same time. Now I floored it in first and got to full boost and ran up the rpms(where I think it drains the bowls), shifted to second, got the boost back in and then it started cutting out/backfiring. Isn't that a sign of being too lean i.e. draining the bowl?
and I STILL CAN'T GET IT TO IDLE CORRECTLY WITHOUT CHUGGING BLACK SMOKE. I reset the float level to where it barely trickles out of the site hole. Lowering the idle below 1000rpm (850rpm) and messing with the idle mix screws still doesn't do anything?! *boucher looks at his PMs*
Also for some unexplained reason now, I have compressor surge. I didn't have it any other time and all I changed was the wastegate springs. What's up with that?
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
Snowman , dont know what else to say,, when you are under full boost & your A/F ratio reads 12.5 to 13.0 range,, that is too lean.
You need to be seeing about 11.8 A/F ratio @ W.O.T (wide open throttle)
What happened to your fuel pump?
MBHD
12 port SDS EFI
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
Ohhh ok. I was getting confused because 13 is rich but you were saying I was too lean. I just now understood that I just need to be richer. Gotcha now...
Nothing is WRONG with my fuel pump but I still have the stock one on. I'm putting on the new fuel pump with the boost reference today. It was leaning it out after I was in boost for awhile so I think I'm draining the bowls.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
DOH!!!!!!! Like I said before, I am really surprized the engine has lasted this long. I thought you had installed the pump w/the boost ref line. Running the float bowl out of fuel & boosting pretty high, running really lean,, I would think for sure,,, KABOOM! Anyone else concur? MBHD
12 port SDS EFI
|
|
|
|
Joined: Apr 2004
Posts: 3,566 Likes: 37
1000 Post Club
|
1000 Post Club
Joined: Apr 2004
Posts: 3,566 Likes: 37 |
It is kind of like playing on the edge of a cliff. One slip and your done. He has been one lucky dude if no damage has occurred.
Inliner Member 1716 65 Chevelle Wagon and 41 Hudson Pickup Information and parts www.12bolt.com
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
Well I installed the fuel pump today but I can't do much until I get my carb sorted out. I set the initial timing (without vacuum advance connected) to 8 degrees and then connected the vacuum advance. No matter where I put the idle speed screw or the idle mix screws, I can't get it to go above bobbing around 10 on the A/F ratio. The best I ever got it was 12 and that's so lean that it backfired or shot up to extremely lean the second I gave it any throttle. Also when I had it at 12, it was EXTREMELY advanced. Much farther than it should've been. I also have size 73 jets. Doesn't that seems kinda big? I sprayed all around my manifold, carb, and vacuum connections and none of them affect my idle even though it seems like I have a vacuum leak. I've set the idle as low as I could to where it would keep its self alive and then I tried messing with the idle screws and they still didn't have any effect and the throttle plates were almost closed. Does anyone have any ideas?
Last edited by snowman4839; 10/26/11 11:09 PM.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
Snowman,
I would try & listen to what Boucher had done to his 2 BBL Holley.
He has recently done modding to his Holley to get the A/F ratios close to what his engine wants.
Hopefully he can post some pics here & you can see first hand on what things to do your Holley.
Turbo6 has been running blow through 2 BBL Holleys for some time now I think he would be a great source of info also.
MBHD
12 port SDS EFI
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
Well I've been PMing Boucher and he's been helping me but hopefully Turbo6 can chime in too.
I still think I just have too big primary jets because if my mix is almost right at full throttle without drilled PCVRs @14 psi, doesn't that mean that my large jets are having to compensate for stock PCVRs and therefore giving me a rich cruise and idle%Pr
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Sep 2008
Posts: 3,673 Likes: 42
1000 Post Club
|
1000 Post Club
Joined: Sep 2008
Posts: 3,673 Likes: 42 |
What size power valve are you running and is it tailored for the amount of vacuum you have. Also, you mentioned backfiring, it doesn't take much to blow a power valve, double check that yours is the correct size and is still functional.
Class III CNC Machinist/Programmer
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
I pull negative 18-20 psi idle and its a 6.5" of mercury pv so I highly doubt its opening at idle. I checked it last night and it still held suction fine and the diaphram didn't look popped.
If I'm really rich at idle and really rich at cruise and close to being at the right a/f ratio under full throttle with 14psi of boost and stock size PCVRs, isn't that all indicative of too big main jets?
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Nov 2004
Posts: 420
Contributor
|
Contributor
Joined: Nov 2004
Posts: 420 |
Lean pop will get the power valve every time at least on the older Holly's...13 this and 14 that is over my head.In the old days we did out tuneing by looking at spark plugs. I even saw "The Cat in The Hat" still doing that on a NASCAR show the other day !!! J
Last edited by SCRAPIRON, #4711; 10/27/11 06:40 PM.
Jerry Davis II#4711
ol Smokey said "one test is worth a thousand expert opinions."
|
|
|
|
Joined: Jan 2005
Posts: 2,123 Likes: 3
1000 Post Club
|
1000 Post Club
Joined: Jan 2005
Posts: 2,123 Likes: 3 |
Mains too big, PVCR too small. Get the size from the body with number drills (the blank end!). The idle rich may be a throttle blade angle/position thing, float slightly high, idle air too small.
Note: all the ratio numbers are not intended to pass emissions, or be chemically correct - they are to save the engine long enough that you can tune it leaner slowly for best results. If the manifold mixture distribution is excellent the final WOT numbers will be closer to 12.2-12.5.
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
I would try to look at my spark plugs but I can only shut off my ignition in reverse so I can't look at the plugs because I'd have to idle it before I turn it off which would erase the sign of the the mix on the plugs.
Panic was right on the money even though I just got to reading it. My mains were definately too big, my PVCR was stock size (too small) and the idle rich was because of my mains. My float was right on and I'm thought you weren't supposed to change the idle air bleed. But here's what I did (I said this same thing in a PM to Boucher) "I'm almost positive that the problem was my jets now. I put the jets (51s I think?) from my other 4 barrel in the 2bbl and tried to run it. It ran like crap and I had to back out the idle mix screws for it to even idle a little bit. I checked my vacuum gauge and my mix gauge and I was at about -22psi of vacuum and it was 17-18 air/fuel ratio so it was pulling more vacuum and running wayyy lean. I'm positive that my size 73 jets were just dumping too much fuel in and overpowering the idle mix screws." So it's very obvious that mains affect idle circuit mixture which is why I need a jet kit.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
If the manifold mixture distribution is excellent the final WOT numbers will be closer to 12.2-12.5.
Panic, these A/F ratios, naturally aspirated or turbocharged, or? I do not think that Snowmans mixture distribution is excellent. I am thinking it has to be off between all the cylinders. There has to be some cylinders running really rich & others running really lean, correct? MBHD
12 port SDS EFI
|
|
|
|
Joined: Dec 2005
Posts: 452
Contributor
|
Contributor
Joined: Dec 2005
Posts: 452 |
Snowman, If your WOT mixture is correct then measure the 73 jet with a drill to get diameter, then measure the PVCR dia. figure both areas add together to get total area. Take about a 66 jet and figure that area, subtract from total to get area to drill out PVCR, install a 2.5 power valve. Turn in idle mix screws all the way in then out 1 to 1.5 turns. Set floats so gas drips out at idle. Set pump shot so there is a little pressure on the diaphram.
Set total timming to about 34*, if you have 22* cent. then set initial to 12* with vac. off dist. and hose pluged. This is not too much with 15# boost. Set timming before tuning carb.
If fuel system is up to par should work.
Do not drill any air bleeds.
Harry
PS make sure the transfer slots are not exposed or drill a small hole in each blade.
Last edited by Turbo-6; 10/28/11 12:32 AM.
Turbo-6
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
Set total timming to about 34*, if you have 22* cent. then set initial to 12* with vac. off dist. and hose pluged. This is not too much with 15# boost.
Harry Harry, not to offend you or anything like like,, but I would think running 34 degrees of total timing & 15 psi of boost pressure, 93 octane & no intercooler is a bit much? Yes, no? Thanks MBHD
12 port SDS EFI
|
|
|
|
Joined: Jan 2005
Posts: 2,123 Likes: 3
1000 Post Club
|
1000 Post Club
Joined: Jan 2005
Posts: 2,123 Likes: 3 |
I agree - without some more development, an L6 manifold is definitely going to have some distribution issues, typically #3 & 4 rich both by being closest to the entry, and also get most of the drops that fall out of suspension. For now, the hot cylinders (#1 & 6?) are the safety target. I've seen best power as lean as 13.2 in NA motors - but those had excellent (even) water temperature, high swirl chambers, tight quench, etc. For a turbo, as long as you trust your anti-knock system you can run closer to best power since the extra gas isn't needed for safety (or at least not as much). Cooling the chamber with gas isn't the best method, but if it works and you have nothing else it's better than losing 1 hole out the exhaust.
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
Snowman, If your WOT mixture is correct then measure the 73 jet with a drill to get diameter, then measure the PVCR dia. figure both areas add together to get total area. Take about a 66 jet and figure that area, subtract from total to get area to drill out PVCR, install a 2.5 power valve. Turn in idle mix screws all the way in then out 1 to 1.5 turns. Set floats so gas drips out at idle. Set pump shot so there is a little pressure on the diaphram. All of what you said sounds right on but why did you chose a 2.5" power valve? Seems really low. Or is that because you don't want all of the extra fuel coming in from the drilled PVCR coming in until you're almost at boost?
Last edited by snowman4839; 10/28/11 01:22 AM.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Dec 2005
Posts: 452
Contributor
|
Contributor
Joined: Dec 2005
Posts: 452 |
Snowman, Yes you don't need all the fuel until your in boost.
Maybe a little less timing with 93 octane, but I thought you were running octane booster.
I think a knock sensor just takes out timing and kills HP, more fuel just uses more gas. I run my A/F at 11:1
On the new cars if you run the best gas you will get more miles per gal. because the computer is not always retarding the timing.
Just my thoughts
Harry
Turbo-6
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
Well I took it out again just to get a feel for what else was wrong with the carb besides rich idle and cruise. I noticed that I either had to go 1/2 to full throttle or barely give it any for it to work correctly. if I pushed it a little bit to cruise, it'd give me lean backfires. Isn't that a accelerator pump cam problem? Like I'm not getting any accelerator pump action at cruise?
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
From what you are describing, it sounds like a lean stumble. Could be pump cam, or squirter size. Or if your jets are really too small. What size squirter does it have?
Did you try a WOT blast & read the A/F ratio?
If now you are only running 4-6 psi of boost pressure as compared to 15 psi of boost pressure, is your A/F ratio richer now only @ 6 PSi of boost pressure? Depending on your A/F ratio @ 6 PSi, you could possibly go leaner on your main jets, only if,you are seeing 11.0 or so A/F ratio now @ WOT.
MBHD
12 port SDS EFI
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
12 port SDS EFI
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
My squirter is a 27 or 28. There's no way my jets are too small from what I've told you guys before. <10 idle and cruise? too big of jets... What are the different types of pump cams?
(This was all still at 15psi), Yes, all of my WOT blasts were low 13s until it lean popped where I stopped obviously. I also did mostly 2/3 throttle blasts and that worked much better and delayed the lean pop a good bit. I only lost a little bit of power between WOT and 2/3.
I think I'm still draining my bowls and thats what's causing the lean pop (but those are also still at 15psi...)
Could I not just get an electric fuel pump? since I am planning on using 15psi anyway? What would be a good choice? What do I need to look for in terms of gph and psi? do I need a regulator with it? I don't know anything about electric fuel pumps but I've read that boost referenced mech fuel pumps only work to like 8psi.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
Hmmm,,,, you were reading 13.something A/F ratio @ W.O.T.,,,, so yes it is & was still too lean @ W.O.T. I guess I will need to reiterate myself, you need to be reading 11.8 A/F ratio or so (in the 11's) when you are running 15 PSI @ W.O.T. Low 13's (A/F ratio) is too lean!Yes, the main jets are causing your A/F ratio @ idle is 10., but I believe there are ways to lean it out @ idle. Your A/F ratio might be OK now w/you only running 6 psi or so. We have not heard anything new if you had installed your new fuel pump & installed a boost ref line. Last we heard, your going to install it, & you are only running 6 psi,, so what is the latest scenario of things that are on or off your engine, boost pressure running now? How much timing? If you are running your new fuel pump & ref line & are running 15 psi & showing 13's A/F ratio still,,(too lean still) then you would need to go w/bigger main jets most likely, unless there are other ways to richen up your Holley for W.O.T blasts. Turbo6 says not to drill out your idle jets,( dont drill just yet) but I believe that will lean out your idle (which you need) to a more fuel efficient A/F ratio in the 14's @ least. Maybe turbo6 can tell you more how to mod your Holley more in detail step by step instruction? I just know the basics & maybe a bit more, but I never blew through a Holley, just my DCOEs. Your lean pop @ 13. A/F ratio is going to melt your pistons,,,, STOP DOING THAT! I initially thought you could run approx 12 psi w/the stock fuel pump, but it seems going to 15 psi is OK according to other websites I have read.?? Research a bit more on that subject. Make sure your float level is adjusted like turbo6 says, so the fuel is just dripping into the carb, meaning, your float bowl area is going to hold a bit more fuel (higher level than stock setting) I thought Holley or another CO. made larger than stock float bowls? I forgot, does your 2 bbl Holley have a plastic float? If not, the brass one would have collasped by now. With the different Holley pump cams, there are white, orange, blue, etc in color & have different ramp rates, meaning depending on cam used, it can aggressively squirt a lot more initial fuel or less. Catch us up to date,, when you first step on the gas,, what is the A/F ratio reading approx? Black smoke, hesitant for the engine to accelerate, almost dies? You need to let us know all the changes you do to your engine so we are up to date on things. Goodluck, & when tuning, try to do one thing @ a time,,, try jetting, test drive,, change timing, test drive it, don't change timing, rejet, & accelrator squirt change all @ the same time. MBHD My squirter is a 27 or 28. There's no way my jets are too small from what I've told you guys before. <10 idle and cruise? too big of jets... What are the different types of pump cams?
(This was all still at 15psi), Yes, all of my WOT blasts were low 13s until it lean popped where I stopped obviously. I also did mostly 2/3 throttle blasts and that worked much better and delayed the lean pop a good bit. I only lost a little bit of power between WOT and 2/3.
I think I'm still draining my bowls and thats what's causing the lean pop (but those are also still at 15psi...)
Could I not just get an electric fuel pump? since I am planning on using 15psi anyway? What would be a good choice? What do I need to look for in terms of gph and psi? do I need a regulator with it? I don't know anything about electric fuel pumps but I've read that boost referenced mech fuel pumps only work to like 8psi.
12 port SDS EFI
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
Hmmm,,,, you were reading 13.something A/F ratio @ W.O.T.,,,, so yes it is & was still too lean @ W.O.T. I guess I will need to reiterate myself, you need to be reading 11.8 A/F ratio or so (in the 11's) when you are running 15 PSI @ W.O.T. Low 13's (A/F ratio) is too lean!Yes, the main jets are causing your A/F ratio @ idle is 10., but I believe there are ways to lean it out @ idle. Your A/F ratio might be OK now w/you only running 6 psi or so. We have not heard anything new if you had installed your new fuel pump & installed a boost ref line. Last we heard, your going to install it, & you are only running 6 psi,, so what is the latest scenario of things that are on or off your engine, boost pressure running now? How much timing? If you are running your new fuel pump & ref line & are running 15 psi & showing 13's A/F ratio still,,(too lean still) then you would need to go w/bigger main jets most likely, unless there are other ways to richen up your Holley for W.O.T blasts. Turbo6 says not to drill out your idle jets,( dont drill just yet) but I believe that will lean out your idle (which you need) to a more fuel efficient A/F ratio in the 14's @ least. Maybe turbo6 can tell you more how to mod your Holley more in detail step by step instruction? I just know the basics & maybe a bit more, but I never blew through a Holley, just my DCOEs. Your lean pop @ 13. A/F ratio is going to melt your pistons,,,, STOP DOING THAT! I initially thought you could run approx 12 psi w/the stock fuel pump, but it seems going to 15 psi is OK according to other websites I have read.?? Research a bit more on that subject. Make sure your float level is adjusted like turbo6 says, so the fuel is just dripping into the carb, meaning, your float bowl area is going to hold a bit more fuel (higher level than stock setting) I thought Holley or another CO. made larger than stock float bowls? I forgot, does your 2 bbl Holley have a plastic float? If not, the brass one would have collasped by now. With the different Holley pump cams, there are white, orange, blue, etc in color & have different ramp rates, meaning depending on cam used, it can aggressively squirt a lot more initial fuel or less. Catch us up to date,, when you first step on the gas,, what is the A/F ratio reading approx? Black smoke, hesitant for the engine to accelerate, almost dies? You need to let us know all the changes you do to your engine so we are up to date on things. Goodluck, & when tuning, try to do one thing @ a time,,, try jetting, test drive,, change timing, test drive it, don't change timing, rejet, & accelrator squirt change all @ the same time. MBHD I'm not arguing with you that it is too lean? I'm just tell you what it is... I'm getting the jet kit on monday or tuesday and then I can start working with that and my power valve restriction sizes (to compensate for smaller jets which will give me that extra fuel at WOT). Then I can get those right. I'm not worried about what my A/F are as of right now because it's all going to change with the new smaller jets. I'm not sure what the last you heard was. I never said I WAS running 6psi. I said I WANTED to run 6-8 psi. But the first time I installed the wastegate, it boosted to 15. I fixed it and it boosted to 3psi. Then I changed to springs to try to make it 6-8psi and it turned out to be 14psi :-(. But that's where it was the last time I wrote. I have the new boost reffed pump on but I cannot check what it is in boost because it's an inline gauge so it's under my hood when I'm driving (and in boost). It also gives me a lean pop at full boost so it's either draining the bowls or the jets/power valves are still too small?? If I floor it while I'm driving, it'll keep pulling all the way til it hits boost, then pull really hard when it hits max boost and holds a 13 A/F then the A/Fs fly to LEAN after being in boost for a few seconds and I get off of it or it lean pops and then I get off of it. It doesn't die though? Partial throttle like I said was bad because it lean popped and stumbled. It was fine if I went to full throttle and back off into partial throttle which is why I'm confident its just the timing of the accelerator pump. Idle and cruise are still rich as all get out. I don't know what the initial timing is at idle but I know with the vacuum advance, it's like 16. I'll have to check tomorrow. I just drove it and got into full boost in third gear and just waited for it to build boost and listened and if it knocked (or if I thought it knocked) at all, I just got off, adjusted timing, and tried again. I was pretty close because it only knocked a little bit so I just kept retarding it until it stopped. I definitely don't have the brass or stock float. I specifically bought a nitrophyl float so it wouldn't crush under boost. I still don't know why it's draining the bowls. I really just think the pump can't keep up even with the boost ref. EDIT: could the stumble in boost maybe be spark blowout? I have them all gapped to .030"
Last edited by snowman4839; 10/30/11 02:11 AM.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Apr 2004
Posts: 3,566 Likes: 37
1000 Post Club
|
1000 Post Club
Joined: Apr 2004
Posts: 3,566 Likes: 37 |
I would prefer to see you use a electric fuel pump and a fuel pressure regulator. You can also get the regulator with a boost reference. You are definately running out of fuel under WOT.
The cruise and idle are going to need lots of tuning. Timing does play a large part here also. While not in boost, the idle will need about 20-26 degrees to be stable. This is achieved using the set timing, mechanical timing (almost none at idle) and the vacuum can. Cruise needs the very important mech timing to kick in. At cruise, the timing could go as high as 50 degrees! Remember, there is no load. But in N/A form the engine likes to see 34-36 degrees toatal timing.
So when figuring in your timing, add these 3 things up:
Fixed timing, this is what you set(ie 8-10 degrees)
Mechanical timing, your distributor mechanical weights set this curve up. Typically 20-26 degrees.
Vacuum can, the can is used for cruise. Can add 15-20 degrees and at different vac points(levels). In your case, kicks out under boost.
Snow, You will not believe what the fuel demand is under full boost. That stock pump will not keep up.
Be sure to see if the pump cam on the carb is ready to squirt as soon as the throttle is moved, this is adjustable. As said before different cams are available as well as squiters sizes.
Harry had mentioned something that may be pertinant here. Large carbs on a small engine. Believe me the 500 has the same size primaries as a 750 4 bbl. You may need to drill 1 small hole in each blade near the shaft to get proper idle. Ussually this occurs with a large cammed engine. This is to allow further closing of the throttle idle screw. The blades will then be below the idle transfer slot and allow proper idle mixture adjustment.
You do need to get a dial back timing light!
Inliner Member 1716 65 Chevelle Wagon and 41 Hudson Pickup Information and parts www.12bolt.com
|
|
|
|
Joined: Sep 2004
Posts: 5,840 Likes: 1
1000 Post Club
|
OP
1000 Post Club
Joined: Sep 2004
Posts: 5,840 Likes: 1 |
As far as reading what your FP is while under boost, you could hook up a hose to a gauge possibly & run it to your windshield & tape it, just to see if fp is rising above your boost pressure. If the fp is not @ least 1 psi above boost pressure you would definatley need a better/upgraded fuel system. Initially, you said you were only going to run 6 or so psi, hence, the use of a stock fuel pump. I am thinking since your car is an OG (original) 6 cyl car, it probably has only a 5/16" fuel line, which is too small & should be upgraded, from the fuel pick inside the tank all the way to the front. V-8 cars usually has 3/8" fuel line, if you are going to upgrade (& I would recommend) 3/8" would be the minimum size to upgrade to. I know, more money, more money, but if you want to go fast & doing it safely, speed is going to cost you. Now you are running 14 psi, you probably are running out of fuel @ this point. This is the type of regulator I would use for a carb set-up. http://www.summitracing.com/parts/AEI-13204/I do not like using a dead head type regulator. With that reg, it has a -8 fuel return that would need to return to your gas tank. Which keeps the fuel pump cool & less noisy. Here ia Holley pump rated @ 16 PSI. http://www.summitracing.com/parts/HLY-12-150/ I would choose this pump for what you are doing @ this point.But if you plan on running more boost, like 20 psi, I would look for a different pump. Here is another Holley pump only 14 psi though. You can shim up the spring & get a little more psi out of it. http://www.summitracing.com/parts/HLY-12-815-1/When I was using the Paxton supercharger I ran the old Holley Blue race pump it had 18 psi. I think the spring was streched or shimmed, I got it from a friend used like this pump here. http://www.summitracing.com/parts/HLY-12-802-1/?rtype=10Stock they put out 14 psi, but like I said, I think the spring was shimmed or streched to increase the pressure to 18 psi. It was pretty loud. I just ran the old standard Holley FPR, dead head type,(drilled/tapped & fitting installed for boost ref line)(picture next to the pump) never really like that combo myself, but it worked & I did not have much money for a nicer pump & regulator. Your heistation off idle, install a bigger squirter like a 31 or so. They dont cost much. Examples: http://www.summitracing.com/parts/HLY-121-131/Different style: http://www.summitracing.com/parts/HLY-121-31/Or, adjust pump ,bolt & nut adjustment where the spring is. Different color pump cam or? Just saying there are different ways to increase squirter output. MBHD
12 port SDS EFI
|
|
|
|
Joined: Jul 2000
Posts: 4,588 Likes: 20
1000 Post Club
|
1000 Post Club
Joined: Jul 2000
Posts: 4,588 Likes: 20 |
If you were pushing 40-50 on the gap then yes you could get the blow-out but i dout that is your problem at .30.And x2 on the fuel line is to small.
Larry/Twisted6 [oooooo] Adding CFM adds boost God doesn't like ugly.
|
|
|
|
Joined: Dec 2005
Posts: 452
Contributor
|
Contributor
Joined: Dec 2005
Posts: 452 |
Snowman, Would you repost your setup as it is now, everything even the smallest detail. And the amount of boost you want to run.
Thanks Harry
Last edited by Turbo-6; 10/31/11 12:29 PM.
Turbo-6
|
|
|
|
Joined: Mar 2010
Posts: 630
Major Contributor
|
Major Contributor
Joined: Mar 2010
Posts: 630 |
Alright then. Ignition GM HEI - new internals. Vac advance hooked to manifold vacuum Old spark plug wires New AC Delco spark plugs gapped to .030" Air/Fuel Delivery Offenhauser 4 barrel intake Chevy 292 exhaust manifold (3 bolt and 2.5" exhaust) Holley 500cfm 2bbl with size 73 jets, 6.5 power valve, and stock PCVR holes 38mm wastegate. Currently opens at 13-14 psi custom uppipe T4/GT35 turbo. .70A/R compressor .68A/R turbine Spectre couplings and elbows for intake tubing. Spectre plenum (turbo hat) 1/8 Oil feed line. Drain line using 10AN fittings AEM UEGO Wideband Sunpro Boost Gauge Stock rotating assembly, and basically stock everything else. My end goal was to run 15psi on a built engine but the stock engine seems to take 15psi fine (IF I COULD GET IT ENOUGH FUEL! and if I don't detonate). Because I've done a bunch of WOT blasts running 13-15psi and it took it fine. I just have problems with my AF mix and fuel bowl staying full. I'm hoping to get a electric fuel pump and regulator soon so that will fix my bowl draining problems EDIT: and I'm going to have to take the engine out and pull the pan and weld in the return fitting (in the right place this time) because the jb weld broke and I don't want to keep having to redo it. Also for some reason, I'm getting a leak from below the turbo right where the return line meets the oil outlet. I have no idea where that came from. So looks like a have a lot of resealing to do. 2nd EDIT: actually is there any way I can get the oil pan off without taking the engine out? 3rd EDIT: if I were just looking for fuel pumps (besides the ones MBHD suggested), what would be the criteria I'd be looking for? Like GPH? PSI? fitting size? And could I not just get that holley blue and use the regulator that it comes with (or modify it?). 4th EDIT: couldn't I just get an EFI pump that produces a lot of pressure and adequate GPH and then just get a regulator that allows me to set the base pressure to 6psi (so I don't flood the carb) and have it rise 1:1? Wouldn't htat have all of my bases covered? because an EFI pump would have plenty of pressure, and the regulator would bring it down to levels usable on a carb right? Like an example is this pump. I doubt that THIS PARTICULAR ONE has enough GPH because 23 is about the same as my mech fuel pump right now. But couldn't I link a pump like this to a fuel pressure reg and set it to 6psi with 1:1 rising pressure? Finally got a couple of decent pictures
Last edited by snowman4839; 11/01/11 07:41 AM.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.
|
|
|
|
Joined: Feb 2010
Posts: 136
Contributor
|
Contributor
Joined: Feb 2010
Posts: 136 |
|
|
|
0 members (),
125
guests, and
27
robots. |
Key:
Admin,
Global Mod,
Mod
|
|
|
|