I have a stock tpi 350 and I have a twin turbo kit for my Z im only looking for about 280-350 hp just nothing too insane just a respectable street cruiser and drag car. wondering if this this would still be able to run pump gas and run 8 to 10 psi with blowing the stock lower rotating Assembly ive heard and read too many conflicted reports about it so just need clarifications thanks

 

You're coming across conflicting reports because people have different ways of tuning. A cooler running engine, with a cooler charge, tuned just right, will allow for a cast rotating assembly to live longer with increased power. Most of it has to do with ring gap, to tell you the truth. Would argue with the Grand National guys regarding the strength of their stock cast rotating assembly in comparison with ours back in the day, and they insisted that their crank (also not forged) was the reason for their strength. Nonsense, it was because of ring gap. Keep things cool with your L98, keep your air/fuel where it needs to be, and keep your timing conservative, and you should be just fine...

- Rob

 

10 psi is nothing. You are fine.

 

its all stock as far as I know changed out the all the upper and lower gaskets. And as far as tuning I think I'm running maybe 12 or 13 advance timing and what ever the computer puts down too and I wanted to know of this thing still good to run on pump gas

 

Don't ever target a specific boost pressure. Just use a four pound spring in the gate(s), then tune your base boost pressure, then increase the pressure in small increments while you tune it until you're happy with the power you're making. Whatever the boost is in the end at the power you want is what it will be, so don't target a specific boost pressure ahead of time. It is what it is...

As far as timing, the stock ECM is not programmed to see boost, so your timing may be too much, even at moderate boost pressure levels because your fueling is not being compensated for either, and it will heat up rather quickly in the chamber. If you have the means to control both fuel and spark, then it won't be a problem either way...

Share your whole setup so everyone knows what you're working with...

- Rob

 

it's the twin turbo f body kit from ebay and the only ignition system thats on there is a msd 6al with the EST dis and stock coil I havent installed the turbos yet cause I broke off the oil line fitting for an oil gauge and had to drill it out and destroyed the threads in the block think I should just retard it back to 10 or 8 degrees? I don't know how far the computer advances the timing at open throttle

 

This is just my opinion, but consider getting the proper chip, or ECM to handle the boost pressure before you install them. I'm not even sure if the $59 code still exists, or decent support for it, but I do know that Turbo Tweak can burn you a chip using their version of the $58 code. You would just need to tell them the size of the engine and the injectors being used, as the data stream is the same for both ECM's. Don't see why Eric wouldn't do it. However, I would highly recommend the EBL-P4...

What you have now from an ignition perspective honestly won't make the cut...

- Rob

 

Stock is 10. You should probably retard it at least 2-3 degrees. The WOT fuel mixture may be ok for 10 psi or less. You'll need to run premium for sure.

It would be preferable to have timing and fuel control. You should look into stand alone ECM options or at least an EBL P4 to get some control. And you'll need to go to a 3 BAR MAP sensor, etc. It's a very foolish thing to strap on a turbo with no way to accurately deliver fuel and control timing. You'll have no end of frustration trying to do that.

GD

 

ok I'll look into it thanks

 

I heard you can use an xfi somthing or another but its too expensive for a brain box and I don't have the technical aptitude to program that kind of thing and where can I find these two items?

 

Hold up.

Before you do anything you need to figure out how you are fueling this and how you will control timing


1: does the msd 6al have a boost reference timing retard function? If not you will need to reduce timing via the chip preferably using the below info $8d boost or $59 code. If you retard it manually then you lose timing all over all the time. Set it to 6 base like stock and either get a boost retard box or modify the code

2: stock ecm either maf or speed density will not control boost fueling. Get that idea out of your head right now. You need an fmu unit to jack fuel pressure up with boost to get fueling, or a speed density system that reads 2-3 bar pressure range. Gotta convert to 91-92 ecm and boost modded $8D code or $59 and get larger injectors.

 

from what ive read I wouldnt need bigger injectors past the 12 psi mark and id perfer not to have to keep playing with timing just to get results just set it one way and leave it there im looking for over 350 hp

 

Again it depends on how you do it. Stock 22 lb injectors will do 350 flywheel which will be 5-6 psi. 350 at the tire will take more boost and require closer to 26-30 lb injectors to be safe

fmu might get you there depending on the pressure rise but will need a good fuel pump. Not the preference way to do thngs.

the boost referenced timing retard box is ideal for you. Set and forget. Running 8-10 deg retarded on the distributor all the time is just not wise imo, your cruise and part throttle feel will suck and hurt economy. Or tou could simply tune the chip, last column just take it out there. But the tune is the most important thing for these things to live. To do it right you need to do it one of those two ways I mentioned.

i have done 3 turbo systems on stock ecms and tuned one blower setup using EBL which is factory style ecm system.

 

when I bought the car the gut said it had 32lb injectors which I don't see it looks like it has the factory 22lbs though. about the ebl I can't seem to find one outside dynamics efi I read that you can use a mega squirt seems like it's easier just to go to carb I'm not real good with fuel injection and computer programming but I am fine with high any thing more than 240 hp