Inliners International Forums General Discussion Blown and Injected intake port dividers (prototype)

guys ,
here is something i am going to try on my motor. everyone knows the siamesed ports hurt performance and tuneabilty on our engines. i have built some prototype dividers and installed them in my motor.
some particulars of my motor. it is turbo charged, and injected, i also have bolt in lumps. i have noticed with the injection @ idle the mixture is not equal on cyl's 1,2 and 5,6, it is because of a timing thing. one of the cyl will get more mixture of fuel than the other. it works out better at 1500 rpm or higher.
so i have made these.






give me your thoughts, remember these are prototypes and will be reworks to a higher quality if the idea works. tom

Tom,

It may work.. maybe it'll help if your getting reversion at low rpm.

Have you got your fuel delivery issue worked out?

Just wondering how you are attaching the dividers?

Also,just to let you know,it may help your fuel delivery problem,but it also kill the flow of your intake port.

It makes the intake port window too small.

You would have to widen the ports just to make up some of your lost intake flow,even then it will not flow anywhere near it does with the one big port.
Hate to sound negative,but dividing the ports did not work for me & it did not work for Mike Kirby.

It should help your low-mid range,but it will kill your top end.
Two cents thrown. :-)
MBHD

I agree with MBHD. I also tried dividing the port and the flow fell off drastically on the top end. I took a fly cutter to the face and built my dividers to the flange and bolted the flange to the face.

efi, the only fuel delivery problem is this one. i am trying to direct the fuel from each injector to the correct cylinder.

hank, they are held in by the 1 bolt going from top to bottom in the port. you can see it in the pics. the other bolt is to keep it lined up with the port.
i hope the turbo will help with the loss of flow.

$um fun, when you tried it was your engine N/A or boosted?


i would have tried running it last night , but for some reason the starter refused to work, go figure. maybe that is a sign. tom

The bolt to keep it lined up in the port, that goes into your intake manifold?

My upper lump ports I made attached to the top w/a bolt also,but the back of it goes to each side of the back wall,,,(like a "V" shape) no need for a bolt blocking airflow.

Let us know how it turns out.

MBHD

Tom, I am now using a stock head with welded in dividers before and after the stock head bolt, also in the intake. but I needed over 30 psi to make the same HP. I felt I had to seal mine since I use carbs, you may not need to since yours is injected. Hope I yours works, as good as mine did all the plugs look the same.

Still fighting an issue with mine hope to have it at the covention.

Harry

Tom, My head was NA and when I put it on the flow bench it looked like the flow was almost cut in in half. I took the dividers out and moved more CFM by raising the port and reshaping the combustion chamber, and straighting the runners on the side. This was on a GMC head and when you open the intake ports you run into the head bolts and even with the tubes installed their is some port choke. I think in all we added almost 75-90 pounds of steel with the welder.

had to charge the battery, imagine that, after a whole 8 months of sitting the battery goes dead. better it than me!
went out and it turned no more than 3 times and starts perfect and idles much better than it had in the past. i will get to drive it tomorrow. i bet it will need to be retuned also. better charge up the laptop tonight. tom

Harry,
how much boost were you using before the dividers? Now 30 psi to make the same power.
Also,how much HP & torque are you making now?
Thanks
MBHD

Hank, was 25# now 34#, 650 to 680 HP close to max of the T70 turbo, in flow and pressure ratio.

Was that flywheel HP, or rear wheel HP?
Did you get a torque reading?
Thanks.

MBHD

guy's, took the mino out after my boys, coach pitch ball game. my other 2 are also in sports stuff, that can sure kill a evening.
anyway, the engine runs smoother, seems to start better, takes less fuel(good now adays)and will still boil the hides off the tires. it took awhile to get it tuned in (10 minutes). it is weird how the plates changed the tune. the fuel from each injector is directed at the corresponding cylinder and not robbed by it's siamesed twin.
i have a privately made program that patch's in with the holley software. simply turn it on and drive the car around for 10-20 minutes. it reprograms all the fuel points on the go! it dialed in too easy. i then ran it thru the rpm range under full throttle and datalogged it all. the Air Fuel Ratio (AFR) was much more stable. so far for a boosted/port injected inline the dividers seem to be the ticket.

my next question is: do i pull the bolt in lumps to gain back some of the lost port volume?

The lumps are not hurting anything with your airflow,,,,,Hum,,
But on the other hand it is making your window port small.
Since you are not normally aspirated,intake port design is not as critical since you are forceing air into your intake port.

If it is not that much of a hassle,,,,,,try taking out the lumps & get back to us.

Best thing to do is widen & raise the roof of the intake ports.

The bolt to keeps your dividers lined up in the port, that goes into your intake manifold?


MBHD

Hi Hank.
Do you have pictures of the upper lumps? I didn't understand how they work, can you help me?
Thank you very much!!!

You can take at the very least .050 out of the top of the ports.Same holds true to the sides. Pull .025 from each side to start with. And see what happens then. The lumps still help the
short turn radiuse even under pressure. My personal thought would widen the Ports first. To make you what you may? have lost with the divider.

Larry, thanks!
But I didn't understand. I installed your bolt-in lumps in the bottom of the head ports (they look perfect and it was really bolt-in) .
So I am asking about the top of the head port lumps. The top of the ports were milled a bit making it flatter. So I install a lump there? It would decrease the intake port volume. I believe this is good if it also has a shape as well as the lumps installed in the bottom. Or not good?
Anyway... Do you have this upper lumps so I can buy again from you? Or they are simple and I can make it?
I am thinking that if I make lumps straight it will reach the valve guide area. Sorry, I am a lot confused.
Also I am not using port dividers and won't use it.
My engine is going good and hope to finish it this year. It is a Chevy 250 normally aspirated for street/strip use.
Thanks a lot!!!
Alex

No not at this time do i make a upper lump. The port if it has not been divided, i do not feel that you need to do anything else
at this time.

The upper lump Hank is talking about that he made went in the
center of the port between the valve guides.

Chevy 250 Opala,
I will take some pics & send to you on the upper lumps.

MBHD

here is my upate on the intake port dividers that i made.
ran thru the summer with them in. many hundreds of miles and lots of full throttle hits. even about 20 runs @ the strip.
engine starts better
idles better
takes less fuel at all speeds
gets off the line better
no more part throttle backfires/ hickups
improved at the strip from a 14.2 to a 13.8 in the 1/4

next i will open up the top of the port and the sides to gain back some port volume or runner size. maybe try to do it yet this year to try it. 2nd , i will pull out the bolt in lumps and keep the dividers to make the runners even larger.

keep in mind, this works well with port fuel injection and a turbo. it probably would not work the same with a carb N/A. tom

tlowe/Tom
The main problem like you are thinking is that the port window are too small w/your dividers.

I think it should run best w/your lower lumps installed & you open up the sides & top of your intake ports,w/your dividers installed.

Now being it's turbocharged (forcing the air into your cylinder head) ,it is not as critical for needed a really nice port design.

It will be interesting to see what works better,my bet is using the lower lumps & opening up your ports over taking out the lower lumps & making the ports bigger..

When you take out your lower lumps & open up the intake ports,you are going to loose a lot of velosity & I would think there goes your lower RPM street drivability.

Having a good short turn radius really helps out w/the airflow & taking out the lower lumps will really hurt it if it was N/A, just not as bad w/your turbo.

The lower lumps also decrease the volume of the intake ports causing the velosity to increase, which in turn gives you better streetability & overall performance,torque.

I keep telling Douglas to install some lower lumps,no luck so far. :-) His car is normally aspirated & I think the lower lumps will help his cause.

MBH

here are some more vids for you all.

http://www.youtube.com/user/telowe2000

pic whichever you like. while watching the vids you can pic the high res version and see everything in good detail.

who knows of a freeware video editor? i have more but want to edit. tom

What's that on the hood?

Pretty quick.

i have added 67 chevelle ss style hood bulges added and you may see my temporary fuel guage taped to the wiper. tom

Probably the tape fluttering then (don't feel bad, I've got the boost gauge for our current hauler duct taped to the box, beind the cab ). Gotta love a temorary install.

Hey Tom:
Nice videos!
Hope you don't mind me jumping in on this thread with a question of my own, but maybe it will help others ,too.
In your walkaround, i think i heard you say you were running .030 plug gap to keep the turbo from blowing them out.
I know you have already said it elsewhere, but how much boost you running? I knew you were supposed to run reduced gap for boosted applications, but i didn't realize you needed to go that far. My 250 is running Splitfire coppers (heat range = AC R44XLS) at .046" off a GM HEI, 7PSI boost, and it just seems to smother out at WOT above 4000rpm. I'm running a stock mechanical fuel pump, so I just figured I was running out of gas. Plus, it's a street driver, RARELY revved like that anyhow, so i just haven't been concerned about it. Think plug gap is the culprit??
Thanks for your thoughts.

Generally, you should not need to reduce your spark plug gap to .030 w/only running 12 lbs of boost w/an HEI.

The only times guys reduce there gap down to say about .026 -.028 on there Syclones & Typhoons is when they are dumping in a lot of methanol.
I run a .040 gap on my Syclone w/an HEI ,I also run a MSD 6A box & normally run 17-22 psi range, I have not snuffed out my spark.

Max RPM on stock Syclones is about 4800.
Stock boost pressure on the Syclones & Typhoons is 14 psi,no reason to run a small gap from the factory.

pappy, i am running upto 12 psi boost. it sounds like you are having the same problem i had. close your gaps to .035 and give it a try. if you have a weaker coil and non performance wires then 7 lbs may be enough to blow it out. mine started blowing out the most in 3rd gear at the 4000 and higher rpms. that is where the longest highest load takes place on the engine.
i have more vid's i can put up but my pc software will not see the file type. want to put out another longer walk around vid.

you could still have a fuel problem, you really should boost reference the pump or atleast the fuel pressure.

hank, i put the gaps there because it cured the problem i was plagued with for so long. i could try bumping it back up in gap. but i know .045 caused the problem. .030 cured it. tom

Interesting vidyas

Tom,
if that fixed your problem, no reason to open the gap back up.

I had .045 gap when running my Paxton supercharger & 8-10 PSI turning 7000 RPM, never blew out spark.

HEI's usually are good even when turbo or supercharging, but blowing out the spark @ only up to 12 psi, seems like something is amiss.

Never has anyone w/there stock Sy's/Ty's has had to close up there spark plug gap & like I stated,stock boost is 14 psi.


MBHD

thanks for the ideas, guys.
one of my winter projects was going to be an electric fuel pump, and i'll shorten the gap, too.

pappy,
i want to see some video's of your ride, i know you are needing to get a camera/recorder.

now , back out to the shop! tom

ok
don't give up, it'll probably be after Christmas.
if Santa is good to me.

Well, it's almost a year later, and I finally got around to figuring out my "smotherin" problem: exhaust backpressure!
Uncapped the headers and ran it thru the gears a coupla times and the little 6 screamed!(new videos attached) First time it has ever wanted to wind 5G's!
I had a feeling that was the problem from the way it sounded, but just couldn't believe dual 1 3/4" exaust thru 2" turbo mufflers would be that restrictive for 250ci.
Anyhow, food for thought if you're planning on building a forced induction system.
http://www.youtube.com/watch?v=6mD6nt3SFoU
http://www.youtube.com/watch?v=Gq8F_cia0is
http://www.youtube.com/watch?v=JcSBNdM7-Xs

Here's some additional thoughts along the lines of dividing the intake ports. About 10 years ago, most of the top Comp 6 cylinder guys began to abandoned the age old practice of "lump" porting altogether. One close friend of mine from the west coast that moved from Comp Eliminator up to Pro Stock truck at about that time told me recently that he always wanted to try dividing the port, but Headrick and Self and the other "lump" guys said there was no way it would work and not to try it. He told me that I knew he has always had the best "lump" heads money could buy and had used everybodies in the industry. He always ran a 250 inch engine in several of the Econo Altered classes for at least 15 years and set many records and won his share of national events, and he said he wanted to think outside the box one last time before he left the 6 cylinders behind. He took an old brazed "lump" head he had laying around, and ground the lumps completely out of the head, and just ported and shaped the head like you would a conventional V8 head. He then welded some sheetmetal dividers to the end of the intake flanges, after he contoured them to fit the port shape. He freshened the valve job and took the existing "lump" port head off his engine and put on the divided port head, and then dynoed the engine. He again re-emphasized the fact that he had used the very best "lump" heads that were out there....and this divided port head made over 50 more HP than the best "lump" head he ever had, and he set a new record with the car as he wound down his time in Comp with the 6 cylinders. Now more recently, my good friend Sherman Sligh, who is still actively racing and winning with his 250's in Comp Eliminator, also runs a divided port head, and he says the intake ports flow 400 CFM @ .900 lift. This is about 50 CFM better than our best "lump" head that we used on Cotton's engine. I think that it is neat that Sissell created such a niche and legacy with the "lumps" that has lasted so long, but its also ironic, that he could have simply stuck a .10 cent piece of sheetmetal into the port and created an even greater legacy and far superior port....

Any photos? I can imagine but I'd love to see.

Sherman wouldn't give me any pics of his head. But he did describe in great detail all the things he did,even saying it looked like an SB2 port turned on its side. He even reshaped the combustion chamber into the more modern heart-shaped style, and ended up with it at 21cc's. Now he can attain the same compression with a flat top that we were getting with a big dome. His divided port is welded in and blended with generous radius' front to back on both sides of the divider. What Darren told me he did 10 years ago was much cruder, but still had impressive results for no more time and effort than it took him to do it. From his description, after he ground the brazed "lumps" down, it appeared much like a head that is ready to install the bolt-in lumps with just a flat floor with the head bolt boss removed. These heads for the Comp motors have a much wider port than the street bolt-in "lump" heads have, but look very similar when they are at this stage of construction. Darren said he just rolled the short side radius with what material was left after removing the "lumps", and fitted the dividers to fit the shape of the profile vertically(floor to roof) as best he could, still having to make a notch to clear the short bolt in the port floor,and welded it as an extension on the end of the intake port flange. Not being an experienced head porter, Darren is however a very excellent fabricator,his dad has the best aftermarket race header company there is, and Darren at 13 or 14 years of age was building headers, and at 16, was competing in NHRA Super Stock and doing good. Again, Darren's approach seemed a little cruder but the results were enough to get your attention. I think for so long, it was just accepted that the "lumps" were the only way to make these heads flow and perform, and no one was looking to find a "next" level to climb to. I know that was our thinking on it. I am currently doing (2) brazed "lump" heads for a guy in South America that are very similar to Cotton's heads, and I am thinking of experimenting with the divider idea. I'll post some pics and data when I get to that point....

CNC-DUDE,
I remember Darren Davis's altered It was a good running car, but didn't know he had a divided head. I also remember reading about Sherman Sligh but didn't know him. Did he weld up the water jacket side of the port to get more width from the port?

Great info. can you get more?

Harry

Harry, when Darren did this, it was the last few races of the season that he stopped competing in Comp and moved up to Pro Stock Truck. Pro Stock Truck didn't last but just a short season itself, so that can kinda' give you a window as to the time this occured. Prior to that, he had also taken (2) of the aluminum Iron Duke race heads he got from Doc Dixson at the Rod Shop and cut them apart and welded them together to fit his 250. He said that was the most awesome head he had ever had on his engine, but of course it was not legal for Comp(and he knew that),the first time out he blistered the index, and got into tech inspection and NHRA tossed the head out. Thats when he decided to try the divided port idea. He already made up his mind to leave Comp and move up, so he was going to just satisfy his curiousity before he did. As for Sherman, he was an old veteran of the "lump" heads, and it was common to grind into the water jacket to widen and reshape the ports anyway, and they are much wider than the ports you will find on the typical bolt-in "lump" street head. Of course, everything in those heads are much bigger, the valves, bowl area and port height and width. But these are all out race heads, and that is just part of the procedures to get them there. Even with Sherman's and Darren's 250 engines, they still used a 2.150" intake valve like we did with Cotton's 292's. I am curious myself now about the divided port, and will thoroughly test one of the heads I am prepping for the guys in S/A, before I fill the ports with brass, and see what hapens. One head will have only the smaller 2.02" intake valves in it, but the other will have 2.150", so I will be able to flow each valve size from stock all the way up. Im sure with time, Sherman will become more relaxed, and possibly take some photos that I can get from him. The aluminum Iron Duke heads is any easy transplant for the 6's, because they have the same bolt pattern and bore spacing, and will give you a killer 12 port head. There has to be tons of those heads out there somewhere....

Thanks,
Keep us posted on your efforts, nothing against bump ports they are great to a point, but I think the divided port,with a bump added to it,is the best direction to go for the next level of performance with a stock head.

Harry