Turbo build: Need your advice

[hamad]

Hello Everyone,

I have a 1987 2WD GMC stepside c10 short bed. The truck is currently in the middle east. I've had it for a while now and restored the paint and interior. I had a shop in AZ put in a LS2 and T-56 for me a couple of years ago. The shop is called Tempe Speed. The car has a 14 bolt with a Detroit locker and the T-56 is built by a local shop as well. The motor is a stock LS2 which is untouched. The car runs great without any issues. But like a lot of guys on here, I want more....

Since I have no fabrication skills, no mechanical skills, I went looking for a shop to do me my own custom turbo kit. I found a shop that will do me a turn key set up. Everything from a full fuel system to a custom turbo manifold. He included a brief description of parts on the phone. These are: Precision turbo (did not specify size), Tial wastegate and blowoff valve, full fuel system with double pumps, injectors, fuel rails, 3 inch intercooler (I think), full piping system (hot and cold side), double valve spring kit, head gaskets, heat shields and turbo blanket, electronic boost controller, oil feed line kit and he will install all of these parts in-house and tune it afterwards.

This guy builds 1000HP+ cars on a monthly bases and is very good at it. He has done this so many time that he has a fixed price for custom made turbo kits for LS swapped vehicles! We discussed running low boost and my goal is 500-550 WHP. I don't want to play with the motor and just keep it stock and dependable.

This guy is asking an arm and a leg for this package ($10K), but with his great skills I believe its the best place to work at. (especially that we have very limited talent and shops here in my country)

Now what I need advice on... This guy is a couple of hours from where I live so I am going to go over soon and want to have a list of questions to ask him before I decide if I wanted to do it or not.

What to ask? What to see? What to consider? Also if anyone had any comments about the set up that I am going to run, or would suggest a different part or route I would be thankful.

I know a lot of guys here will say "there is a more cheap and easy way to get 500 WHP" but I have the turbo bug and really want to turbo my truck.

All opinions and advice is welcome and I will provide any information to help you help me

Thank you in advance and I'm looking forward to seeing your advice

(Wish this thread is in the correct place, forgive me if it isn't)

[andrewmp6]

For half the price you can buy a supercharger http://whipplesuperchargers.com/inde...&product_id=90

[MikeB]

I'd ask him about supercharging, and its pros and cons vs. turbos.

Also ask if premium pump gas will work, or if you'll need aviation gas or an octane booster. The LS2's compression + boost might be a bit much for pump gas.

Sounds like your drive train may be up to handling the power, but how about your brakes and suspension?

Finally, I'd call Kyle Thompson at Thompson Motorsports for his opinion:
http://www.thompsonmotorsports.net/p...roducts_id=169

They have built over 1,000 LS engines, from stock to boosted. A buddy of mine had them build an LS6 short block for him, and I was very impressed with Kyle's knowledge, his machine shop, and the scope of the operation.

[enaberif]

For a heavy truck I'd rather take a supercharger over a turbo any day. The supercharger will give you immediate power unlike the turbo.

[andrewmp6]

That 10k sounds really high to me,Will the turbo system be build on your truck or one like it and pray it fits?

[SCOTI]

10k for parts, labor, & you get your truck back done/complete w/the proper tune in weeks vs years is not bad. Sure a Whipple SC kit can be purchased for a little over half that price but it's going to cost $$ for that install as well (I'd bet the turbo + support stuff alone is over 1/2 the bill).

That being said, one thing you want to know is the expected boost level & what fuel requirements there will be.

Sounds like a fun project....

[cerial]

With your compression ratio you are going to only be boosting at higher rooms. You are going to be running premium and meth to keep things from pinning.
If you want to run pump gas you can lower your CR down to 8.5 or 9. But, you are going to be loosing low end torque. The turbo will need to produce more psi on a lower CR engine to make the same hp as the higher CR engine which needs less psi and less spool time.
It all comes down to proper tuning.
This all being said your talking like 600hp at the crank. That is going to take a bag of tricks to avoid running anything except premium. The amount of time not filling those cylinders with fuel when there is no need to do so will be a large factor in mileage.
I prefer to keep the engine simple and make power through gearing. For 10k you could install a 6 or 8 speed that would make more power at the wheels then a 700hp engine.
Once again it is all about tuning.
But, running 550ft/lbs With a 3.73 ratio yeilds around 2000 lbs at the wheels.
Running 450ft/lbs with a 4.56 ratio yeilds around the same 2000lbs. The difference between a 550lb and 450lb engine is massive reliabity wise.
Having a transmission that can lower the highway rpm to a ratio less then that of the t56 lets you have more rear gear. That all being said I did not even factor in the torque multiplied by the transmission or the reduction in lost rpm during shifts which leads to increased torque and increased acceleration.
All comes down to making it all work ttogether and what your goals are.