Inliners International Forums General Discussion Blown and Injected draw thru turbo

You can write what I know about turbos on the head of a pin and still have room for the library of congress.

That said, I asked a question on this forum a few months back and one of the carb guys (carbking????) said that original Carters could be made to work with blow through fairly easily, the clones (Edelbrocks) were not good candidates.

Is there a turbo for dummies tutorial anywhere???

Tom Lowe, if I wanted to do a turbo for the 250 with the head I got from you, what would I need?

Kerry Pinkerton,,,

The old Carter carbs would still need the floats replaced with non crushing type IE plastic.

Problem w/running an old carb is that the throttle shafts will probably be worn & will leak under boost pressure & make a mess.

When I was blowing through carbs, I choose the Weber DCOE side draft,ballbearing throttle shafts (don't wear out) plus the shafts are sealed.
I still needed to buy plastic floats,the brass ones crushed under boost.
You can choose what ever carb you like ,but I think the Holley & Holly look a likes are proven & literture can be had for blow through set-ups.

There are books out there on how to modify carbs for blow through applications.
Or you just install a complete incloser/Carb bonnet, then you do not need to worry about throttle shaft leaks,vents leaking,etc.

I have not seen a carb bonnet on an inline Chevy six,so not sure if it will fit. I would think the carb might have to installed sideways?

Look at Amazon books,for turbo books & carb mods.

MBHD

I have not done it but I'm sure the Studebaker carb box that Lionel Stone sells would work on our inlines. If it stops snowing tomorrow I'll check. I've got one out there somewhere. I've always thought a military ammo box would work.

Hear are some carb bonnets, they do not enclose the entire carb.

http://www.vs57.com/bonnets.htm

Here is an enclosed one on Ebay
http://cgi.ebay.com/ebaymotors/_Car-Truc...A1%7C240%3A1318
Quite pricey
http://www.superchargersonline.com/product_detail.asp?PartNumber=PAX8PM205-012
Carb mods http://www.vs57.com/carb.htm
MBHD

That first link is great! Here are some pics of an R3 Studebaker type air box. It is 13 1/2" wide, with about 2 more inches for the throttle linkage, and 11" front to back. From the back carb bolts to the back of the box is 2 1/2". Mounted side ways I think it would work. R3 Air Box

There is a group on Yahoo called carbureted supercharger and you do have to apply for that group and be approved by the moderator but there is a really good section under "photos" is the modification process ypou would need to do to make a carter or edelbrock a blow thru. It is in a folder called "Carter AFB mods" on the first page. This group is a little out there though and trying to follow the dicussions is really tough due to the format but the section I went to the group for is very informative. On more than one post where some guys were arguing FI vs. Carb it was stated sveral times that an Edelbrock Thunder AVS will support 7-13 lbs of boost righ out of the box, don't know if it is true or not but I'm not spending $300.00 to find out. Also on the sight for McCulloch super chargers also has good instructions for several different carburetors.
http://www.vs57.com/carb.htm

Here are the Buick Regal & Turbo Trans Am draw through turbos differences.
http://www.turbobuick.com/forums/before-...tml#post2083325


MBHD

OK so I have not been on for a while because I had to take some time to get some parts together. I have taken the advise of several rather experienced members and got me a turbo from a 79 buick. I am in the midst of my manifold fabrication and have also acquired a bunch or new stuff like an MSD 5462 boost timing master, Holley 600 cfm carb with boost referenced power valve from Sthale, and a ProComp black pump (set to 9psi max). The one purchase I have yet to make is a fuel pressure regulator. Being how I have more parts than knowledge of this draw thru setup, do I need a rising rate fuel pressure regulator? Will a chemical intercooler be a good/worthwhile investment? Any cam suggestions? I was going to use the comp cams magnum 499 lift.

You do not need a boost referenced regulator for draw through since float bowls only see atmospheric conditions.

What type intercooler, may not be needed at such low HP level.

Maybe try water/meth injection.

W/a draw through set-up,you do not use an intercooler,only for blow through.

Chemical intercooling is a wise choice if you are running low octane or not using an intercooler @ all.


Comp cams magnum cam specs please.


MBHD

When I said what type intercooler I meant to put a (?).

Is chemical intercooling nitrous oxide ?

That may work if added after the turbo but don't you still need to add fuel ? Or can you just add a little nitrous oxide.

Thanks Harry

It could be,but I was referring to methanol injection.


MBHD

Thanks, I hadn't heard of that term (chemical intercooling) used before. The new setup around here is doing a blow through carb on gas, without an intercooler, then when it goes to boost injecting massive amount of methanol. The talk is of making over 2000 HP with a small block.

Guys use methanol injection a lot on there Syclones & Typhoons.

Most run on pump gas 91 - 93 octane,run anywhere from about 20-30 PSi range & run a range of 16- 25 degrees of timing.

I use 91 octane & run about 21 psi.

It's been a while since I checked ,but,IIRC I run approx 18-24 degrees of timing.


MBHD

Yeah maybe the horsepower expectations have gone up a little. I have two water/alchohol injection kits. One is a stage II from Snow and the other is the old school Edelbrock Varajection. The reason I am going with the washer fluid in the engine is because my engine has snowballed into the 10.5 : 1 compression range. I have went from the simple project I wanted to this 194 head, self ported, self lumped, Magnum Cam, roller rockers, 40 over, forged pistons, set for e85. Now I have really done it and got a t3/t4 Precision hybrid. Garrett compressor 456159. .60/.63 ar 50 trim.
How do I install a carbon seal in this thing. Is there a kit or do I need a new backing plate for the compressor? Or is this something else to throw in the mill?

10.5:1 is way too much for a turbo set up! You talk about the simple project you wanted. Who made you want something else? There is a good story in Bill Fisher's book about a strong street engine he built for a guy who was impressed the next weekend by a race engine and made a lot of costly less streetable changes. The hardest thing to do in this game is to be honest with ourselves and plan an engine that fits our true needs. A friend of mine has for years advocated the "best" (simplest) street motor as a stock 250 with a draw through turbo. Engines were plentiful and cheap then. His plan, build a turbo set up and run it on junk yard engines till you blew it and get another. Somewhere between this plan and yours there is a strong drivable 250. Where are you going to be when the "snow ball" melts?

AFAIK a backing plate may do it, but are you sure this is not already sealed?
I agree, 10.5:1 is above the normal safe choices for turbo, but if max boost is mild (10 psi?) and you don't mind a lot of T&T to get the advance, vacuum advance/retard, knock sensor, and anti-det injection adjustments good it could work. The safe settings must kick in just before you get to low vacuum (even before boost) with that static CR.
The usual warning: 1 mistake + 10 seconds of full throttle = drive over the crank.
Re: Magnum cam. This is 268° nominal, 218° @ .050", 110° LSA. The range is OK but IMHO that's too much overlap.

I figured between the E85 fuel and the alcohol/water injection I should probably be ok. I have ran a blower on a 11:1 motor (455) before with nitrous and no intercooling or aftercooling.
As for why.....because I sold another vehicle I had now have a couple grand to play with and have not seen it done yet around here. Expected boost level is 8psi street but I know I will probably try it at more like 18-20 at the track just to see if it will live. Don't really care if it does, I have the engine with the GN turbo as a backup. I have this turbo apart and it has a dynamic seal. PANIC, where can I find more info on the part you have mentioned.
cam is Magnum 280H (have the springs too)
280/280 adv duration
230/230 @.050
.536/.536 lift
110 lobe center

Running E85 is bettor for high compression engines & or high boost,but,,,, 10.5:1 is a bit high. All though I just realized my wifes turbo Audi has 10.5:1 compression ratio,,,,but it has all the lastest to control & detect detonation.stock it sees about 12 psi of boost pressure. But w/a chip/software downloaded into the ECU you can run 18-20 psi on 91 octane.

The camshaft would work much better if it had a LSA of 115-116.

What size or stage is the turbine wheel?

With a draw through turbo,you need one that is made for a draw through application.
Can you return it & get a turbo that is made for what you are going to do?


MBHD

The turbo was kind of a payment/gift/barter from a co worker of mine who needed some parts fabricated for his brothers SRT-4 (very very very fast little car) so beings how it was free I can totally feel free to spend money on modifying it to work. I tried to give him $100 for it but he would not take it, instead gave me the wastegate too. So if I tell him I need a different one he might go buy it for me (kidding). I do not know any other specs on this turbo aside from p/n 456159 on compressor which is a t4 .60 ar on compressor, .63 ar on exhaust and was told it is a 50 trim.

It it was for a SRT,I will veture to say that the turbine wheel will be too small for your application.

It will work but will be severely restricted on the exhaust side.


MBHD

Oh, I see, there is a plan. Then you're right on track!

This is by no means a small turbo, not stock from the Neon. It was an 11 second SRT4 and this turbo is WHOLE LOT bigger than the Buick turbo. The inlet is about 2"-2 1/4" diameter. It is in my tool box at work so I can't tell you a sure measurement. The turbine wheel from this turbo is 3/4 the size of the turbine HOUSING of the turbo from a 1979 Buick.

I know the 10.5 (actually 10.44) may be a little much but I don't want to have too much lag and I really think between the low temp and high octane of the E85 fuel and the heat quenching ability of the water combined with the alcohol, throw in an ignition retard system it may just live. I am also trying to work on some sort of regressive boost control system to give me peak boost at a midrange rpm and then back down at peak rpm. Like wastegate set to 14 psi until 3800 rpm and starting to back off 1psi per 500 rpm so it comes back down to 10-11psi when I am ready to shift. I figure a progressive nitrous kit but in reverse, that way I will build excessive cylinder pressure at high rpm.

If I am reading you correctly,,,your new turbo,,the turbine wheel,,,is smaller than a 79 Buick turbo?

You will need the turbine wheel to be approx 2.5" diameter,measure the exit hole of the turbine housing when you get a chance,,,,I still think it is going to be too small, but well see

Turbo lag will be a bigger problem w/a draw through set-up as compared to a blow throught set up.

You just need to correct sized turbine wheel & turbine housing mainly to get proper spool-up.

My Syclone has 8.4:1 compression & has minimal turbo lag.


MBHD

No I mean just the the compressor wheel only from the new turbo is almost as big in diameter as the entire compressor housing of the buick turbo. The thing is huge. The guy was running 34 psi on the neon but the thing was too big for that car. He stepped down to a 50 trim the one I have is actually a 70 he said. I do see 70-t marked on the compressor. All I know for sure is that the whole buick turbo is about the size of the compressor and center section of this one and the compressor wheel from the buick falls in and out of the compressor OUTLET on the new turbo. (both are apart and I was playing with the pieces)

The compressor housing is a b trim I think (6.121" diameter backing plate), wheel is 70 trim wheel diameter is 3.985". outlet is 3.25".
I am running into a huge problem finding a backing plate for this turbo that will accept a carbon seal. Trying VW sites but no luck yet. If andyone knows of anyone who can help.....

What size is the turbine wheel?
What size is the exit hole (on the turbine housing) for the exhaust/downpipe?


MBHD

I think gpopshop.com can help you out. They have collars for encapsulated carbon seals. I think p/n 456159 is a Garrett number but I know they will find your part if you email them a picture of your turbo.

Z