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-   -   Twin turbo firebird (https://forums.maxperformanceinc.com/forums/showthread.php?t=830865)

gata79 06-30-2019 05:42 PM

Twin turbo firebird
 
I’m thinking of building a twin turbo firebird. I have a 1970 firebird that I was going to build a fairly radical NA engine for. The plan was to have a very fast car to drive on the street. But now I’ve been seeing a lot of turbo cars be faster and more street friendly.
I have an aluminum IAII block, 4.5 steel crank, Oliver 6.8 rods and 4.35 pistons with a 27 cc dish. The block is already bored for the pistons. For heads I have a set of wide port high ports or a set of 380 high ports. Both with 56 cc chambers. KRE told me they can redo the chamber up to 80 cc’s.
I’ve built many na Pontiacs, but never a turbo. Where should I start? I know headers are a problem. I can change most of the above parts if I need to.

gata79 07-07-2019 07:47 AM

Well, forging ahead I’ve ordered a 4 inch stroke scat crank from Butler. I’m going to order pistons Monday. I called a couple of guys about headers, but haven’t heard back. I’m not sure about turbo sizing or brand. Again I’ve called people and left messages but haven’t heard back. This may be a difficult build, but it’s going to happen.

Tom Vaught 07-07-2019 09:24 AM

Street Car that makes good power, hard to beat a correctly matched Twin Smaller Turbo Set-up. John Meany (Big Stuff 3 Owner.Dyno Guy) had a 1000 hp Corvette (SB Engine) that was about as violent as you would ever want on the street.

Going to the 4" crankshaft was a smart move.

You should have all the power you need or can put on the pavement.

Spend the money on Quality Turbos from Turbonetics/ Precision Turbo.

Tom V.

gata79 07-07-2019 01:14 PM

I guess I didn’t say in my original post all of my goals. We have a version of the top 10 list at my local 1/8 mile track that races on Thursday. The only real rules are street legal, tags and insurance, and no alteration of the rear wheel wells. They can also make us take them out on the street to prove they’re streetable. I’ll need to run high 4’s to be competitive. Most of these cars drive to the track, and are turbos. I already have a dedicated track car so I want to try this. John, I don’t know why but my notifications won’t open.

johnta1 07-07-2019 04:16 PM

That's what I was afraid of.
(if you're talking of me)


I have twin turbos with wastegates still for sale.


johnta1@wallaceracing.com


:)

gata79 07-18-2019 04:40 PM

I don’t think those will be big enough for what I want to do John.

Tom Vaught 07-18-2019 05:28 PM

The Turbos John Wallace has for sale were Custom Built Turbos and each turbo was rated for 500 HP. How much hp above 1000 HP are you looking for?

I originally sold the Turbos and Wastegates to John, years ago, for his Dragster but he never installed them. Should still be brand new parts.

Tom V.

GTOGEORGE 07-18-2019 05:34 PM

Quote:

Originally Posted by gata79 (Post 6038932)
I guess I didn’t say in my original post all of my goals. We have a version of the top 10 list at my local 1/8 mile track that races on Thursday. The only real rules are street legal, tags and insurance, and no alteration of the rear wheel wells. They can also make us take them out on the street to prove they’re streetable. I’ll need to run high 4’s to be competitive. Most of these cars drive to the track, and are turbos. I already have a dedicated track car so I want to try this. John, I don’t know why but my notifications won’t open.

Your going to need 1,400 HP to run high 4's in the 1/8 mile! that probably 14-16 lbs of boost with a good flowing head a camshaft.


GTO George

Tom Vaught 07-18-2019 05:36 PM

The Turbos that Wallace has are nowhere near 1400 hp turbos.

Tom V.

JSPONT 07-18-2019 06:52 PM

High 4's with an uncut wheel well means small tire. If you can run a high 4 on the street with a small tire, you will be the king of the small tire in this country.
Last month at a small tire airport race, there was a 200,000.00+ car there with traction control all the bells and whistles, high 5 at best with small tire on the street.
Anyway, headers are a pita for Pontiac, If I was to do it over, I would built a log manifold. Good luck on the build keep us posted

68azbird 07-18-2019 08:01 PM

1 Attachment(s)
Yea Logs

charlie66 07-19-2019 06:32 AM

Quote:

Originally Posted by gata79 (Post 6038890)
Well, forging ahead I’ve ordered a 4 inch stroke scat crank from Butler. I’m going to order pistons Monday. I called a couple of guys about headers, but haven’t heard back. I’m not sure about turbo sizing or brand. Again I’ve called people and left messages but haven’t heard back. This may be a difficult build, but it’s going to happen.

Your best bet will be to keep it simple. Short and sweet with the header. If you have the ability make your own. Keep the primarys between 1 3/4" to 1 7/8" and the collector needs no more then to be 2 1/2" . Anything more is just for show and will slow down spool..

If you can aford it. This turbo would be good for what you want to do when set up as twins IMO....

https://www.precisionturbo.net/Stree...PT6875-CEA/661

Good luck . Should be a fast car when all said and done.....

gata79 07-19-2019 12:36 PM

I’ve got a local guy who is going to build the headers,mounts and other tubing. High 4’s in the 1/8 mile. I talked to Travis Quillen last night, he says he retired, but recommended 2 precision 7675 and Holley FI. I need around 1400 HP.

GTOGEORGE 07-19-2019 12:41 PM

Quote:

Originally Posted by GTOGEORGE (Post 6042020)
Your going to need 1,400 HP to run high 4's in the 1/8 mile! that probably 14-16 lbs of boost with a good flowing head a camshaft.


GTO George

Like I said! LOL!

GTO george

charlie66 07-19-2019 02:44 PM

You can over 2000hp with the par of 6875s. And spool better..

RUDOLFSSON 07-19-2019 08:05 PM

Nice parts you have there going... You need a LIGHT & consistent car to reach your goals no matter what HP number they tell you! Small tire racing is tricky stuff !!

Personally I'd go with the more mass non wide port heads.. more durable clamping for sure.


Kris.

gata79 07-19-2019 08:23 PM

That’s what Travis said. Heads that flow around 320-330. I have a set of high port heads from SD that flow 380 that I’ll probably use.

GTOGEORGE 07-19-2019 09:14 PM

Quote:

Originally Posted by gata79 (Post 6042393)
That’s what Travis said. Heads that flow around 320-330. I have a set of high port heads from SD that flow 380 that I’ll probably use.

The better heads the more HP you can make!

GTO George

Boostedbird 07-20-2019 04:12 PM

I think the 76/75's will do well. Making the power that you'll need shouldn't be a problem with what you have. I'd start thinking of the driveline. Too deep of a SLR will give you trouble hooking up.

gata79 07-20-2019 04:47 PM

I’ve been racing this car for years. So it’s set up pretty well for NA. It has a turbo 400 with PTC converter and 373 gears. I’m thinking 2.10 first in the 400 and 308 or 323 in the rear. It has caltracs and single leaf springs, frame connectors and a roll cage. I know I’ll have to update the rollcage.


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