10 turbo set-up questions

i recently purchased two turbonetics t04e turbos and plan on hooking them up to my forged internals vortec engine. Im using the vortec L31 heads w\ big valves, stock stroke and a homeade EFI using the holley 950 commander management system, 2000cfm throttle body and a vortec air-gap intake. i will also be using a water injection unit.

Question #1: what would be the best cam for my set-up? #2: will the factory hyd. roller rocker lifters be ok? #3: What type of pistons should i use? #4: i was looking at running 8:1 compression, how many PSI can i run? #5: what is the maximum PSI can i get out of my set-up. #6: what size injectors should i use? #7: is there anything i should have done to the heads, like porting, to better suit the twin-turbo setup? #8: how much HP am i looking at? #9: where did you turbo sbc guys get your headers, or what do i need to weld up my own? and finally #10: do any of you have any other suggestions i should try

the engine is going in an 87 IROC, with a 95 t-56 tranny.

I will take a stap at these questions.

1. I would suggest a hyd roller cam on the small side. Ex: 224int/218exh on a 110-112, up to 232int/226exh on a 114... the reason for the diffence in LSA is because I would recommend keeping the overlap around 0 or even a negative overlap.

2. Aslong as the lifters are strong enough to not collapse at high RPM, im sure someone else could answer this more intelligently.

3. I would use atleast a forged 4032 or 2618 piston. 2618 material is probably the best material and what I have purchased. SRP is made from 4032 and Ross is 2618.

4. 8:1 will allow you to run as much boost as your turbos will make. Guys running over 30lbs use 8:1. You will run out of turbo way before that point.

5. I don't know about the max psi, can you find out how much air each turbo will flow and that will give you an idea of the max HP potential.

6. You need to know the HP before this can really be answered.

7. It would have helped but its not a must. You can still make about the same HP, it will just be at a little higher boost.

9. This is dependent on your budget. Ive seen guys turn a set of good shorty headers upside down and make the rest. Or you can buy bends from EPD (I think thats the name) and weld your own either in steel or stainless. I bought steel and with nice collectors and flanges had about 800 in parts, I think you can double that for stainless but you don't have to get stainless coated.

I did a real quick search and best I can tell a single T04E can support 600HP...am I close on this number?

If so you can probably expect around 950 max'd out because there will be some efficiency loss running twins. With the heads you have I would guess you would need 25+ psi to achieve that kind of power. Maybe that is more radical than what you want to do but I think it can happen.

The answers to a few of your questions will depend on the Holley EFI system. I don't know anything about it's capabilities so you need to know or find out:

If it can run a 2 or 3 BAR MAP sensor
If it can run low impedance injectors

If it can't run a positive atmosphere MAP sensor You'll need to run an FMU or some other band-aid solution to fuel delivery under boost.

Why the water injection? Do you not plan on intercooling it?

If I had one suggestion to anyone building a turbo car it would be to save your nickels and dimes and run a FAST engine management system with an in-car wideband O2. This system alone will allow you to run more boost safely due to it's ease of tuning and you will be far less likely to scatter parts if your air/fuel ratios are correct.

Originally posted by Whistler
Why the water injection? Do you not plan on intercooling it?


i was going to use some sort of aftermarket front-mount TT supra intercooler, but the main reason ive decided to go with water injection is to save space, the only way i can think of mounting an intercooler in a 3rd gen would be in front of the radiator, and i dont want to rob the radiator of any air. plus its about 700$+ cheaper:D

Ill take your advice and do alittle research on the FAST engine management system aswell.


Originally posted by Whistler
If it can run a 2 or 3 BAR MAP sensor
If it can run low impedance injectors

the Commander 950 EMS can run a 1,2, or 3 bar map sensor, as well as up to 8 low impedance injectors (just need extra software i think)

If the Holley can run a 2 or 3 BAR MAP and big injectors then the benefit of a FAST would be mainly the in car wideband. What is the cost of the holley setup?

Any reason you're running a dual plane intake on a port-fuel setup?

-Chris

Originally posted by Whistler
If the Holley can run a 2 or 3 BAR MAP and big injectors then the benefit of a FAST would be mainly the in car wideband. What is the cost of the holley setup?

the holley setup costs pretty close to $1700 with the 2000cfm throttle body, i figure another $600 for the incar wideband controller and 02 sensor.


Originally posted by Chrisbequick Any reason you're running a dual plane intake on a port-fuel setup?

The main reason is because its the only intake (besides an edelbrock performer) that i could find to fit the vortec heads. hopefully there will be no downsides to the dual plane.