My sleeper T/A at car show
 

That's real nice !

Incredibly awesome!

Are you happy with the FITECH system so far?

Tom V.

Hey Tom yes the FiTech is pretty damm good and easy to setup but there are a lot of parameters in the system that unless you are a tuner which I am not, it can be confusing but with somebody who can understand the terminology of what can be adjusted it would be benifical... my car did not run right with a carb on E85 and now runs great it could be fined tuned better but need to find a tuner to do that because every time I start messing with the pro tuner section of the unit I get myself in trouble ... but I would highly recommend the FiTech system over a carb .

Great to see another turbocharged Pontiac street car, looks awesome!

Looks great!! Keep us updated on the fi tech tuning progress.

Whos E85 carb did you ran? Thanks.

Be careful with turning that boost up. On E85 that fi tech is only good for around 800 h.p. 1200 on pump gas. Watch the a/f close. At 12 psi you should be over 800.
Car looks great by the way!

Thanks Jeff, I know about the 800 hp on e-85 which sucks ..... at the track I can switch to race gas and retune the a/f stays the same all you have to do is put the correct engine size back in the program , now I add 30% to the size for E85 ....

Do you have any links to your build? Car is awesome!

Sorry I did not keep a build update as I was trying to hide most of it from my wife 😂 but I can answer any questions about the build if needed

I'm most interested in how you have your manifolds, wastegate and oil feed/return lines routed.

Did you utilize a water jacketed center section?

I have a stock drivers side manifold then a crossover pipe that goes under the car around the oil pan to a handmade custom log manifold , the oil feed line come of the block next to the distributor location, the oil return is a #12 braided Teflon hose that goes to the oil pan in front right under the timing cover were I have a 3/4 “ pipe welded to the pan with a 12 an fitting on it .....the turbo drain is a straight shot to the pan with slight bend this is very important .... hope this helps

Thanks, that's absolutely helpful!

Sounds like you have all of the bases covered on your TA, Great Work.

Tom V.

Thanks Tom , hey do you think having a 3.5 “down pipe going into 2 - 2 1/2 “ pipes is a restriction on hp ?? Is a 3” exhaust system in order ?

On my setup, I have a 5" downpipe about 2 feet then neck down to 4". Then I'm going to do a two 3" pipe to the muffler. This is with a PT91.5 G trim single.

NA two 2.5" pipes support 500 hp with NO restrictions. Two 3" around 700 hp before it starts to restrict. You can certainly make power above those levels, but that's the @ power level those pipe sizes support before they start creating restriction.

Starting out at 5 and gradually reducing helps reduce back pressure. The turbine will like lots of expansion at the exit, so don't get shy if you have space for BIGGER!

The larger down pipe right off of the Turbine discharge does two things:
1) ALLOW THE SWIRL FROM THE TURBINE TO CHANGE FROM ROTARY MOTION TO LAMINAR FLOW.

2) REMOVE MORE HEAT FROM THE EXHAUST IMMEDIATELY AFTER IT EXITS THE TURBINE (MORE SURFACE AREA TO COOL THE EXHAUST.

You really only need about 12" of length.

Example: A 12 inch piece of pipe 4 inches in diameter will have 150 cubic inches of volume to convert from Radial Flow to Laminar Flow.

It will also have a large enough surface area to cool the pipe flow so that the exhaust has a denser volume and can pass thru a smaller diameter efficiently. Going massively long on the length really just allows the exhaust to pack up in the volume and disrupt flow.

Tom V.

Thanks Tom , so my downpipe now starts off 5” right off the turbo for only 4” then I have it reduced down to 3.5” for about 4 feet to get under the car where it goes from 3.5” to dual 2.5” merge pipe all the way out the back . Was thinking about going from 5” off the turbo to a 4” for about 4’ to get under the car then go from 4” to a dual 3” merge pipe all the back..

You are welcome. Like I said 5" off the turbo for 10-12" is fine then reduce to the 4" downward to under the car, etc.

Tom V.

How does it sound? Any pics ?

Here is a video my buddy shot about 9 years ago. 5in to 4in until just past the transmission. then it splits into 2- 3in pipes into 3in dynomax ultraflows. then 3in over the axle and out the back. Probably about 80lbs of pipes! lol. Its almost too quiet but its what I wanted, a sleeper.

https://www.youtube.com/watch?v=Osf-qINumqY

I've got about 3ft of 5" reduced to 4 as it turns parallel to the ground then split 3". I utilized my existing 3" x pipe. Just trimmed down the drivers side entrance and welded it up. I recall reading way back when doing this that you needed as much 5" off the housing as possible before reducing but since then I've seen many setups that didn't follow that and run well.
I'm sure Tom has the actual answer to that

The reality is n2ogpsj462 that the vehicle package has a big effect on what you can actually run with the large (say 5" tubing) before you have to make the downturn to go under the dash area.

If you have a remote filter set-up you might be able to make the 90 degree turn with 5" and go a few inches more before having to make the second turn sending the exhaust towards the rear of the vehicle.

If you can't package the 5" turn and a bit of 5" downpipe (in the space) you might as well just reduce to 4" before the downturn and plumb it that way as far as you can.

Again "Package" defines most turbo plumbing in today's world.

Tom V.

Is the serpentine belt system from a kit or made to fit using different pieces?

Separate pieces crank pulley is off a 5.0 mustang that machines out slightly to fit the Pontiac balancer and the rest is from a Buick grand national ...

May I ask what years Mustang pulley will work and does the Buick alt. and P.S. brackets bolt right up to the Pontiac engine. I would like to do it without A/C. Other people on this forum may like to do one both ways.

I got the crank pulley off a late 80, 5.0 and the rest ac, alt, and power steering pump is all from a grand national with a customer one off adaptor plate to bolt the grand national accessory bracket to a Pontiac head