I have a 88 7.3, about 150kmiles. ZF5, 3.55s. R&D stock injectors. Reman pump with unknown miles or origin. Used banks sidewider turbo, with straight 3 inch exhaust. Still using headbolts, no studs yet. Oil pressure 36-38 on the road, 22-25 idle hot. Truck was original N/A with C6.

Anyway. when I first finished putting the truck together I turned the pump up about a flat. No smoke. Found on the highway I could cruise 65-70 with about 2PSI and 5-700 EGTs depending on hills or how I was driving. WOT would be about 11PSI and never saw higher then 750-800EGTs (empty, truck probably will never be used to tow.)

I was bored last weekend and turned the pump up another flat. (Probably turned up about 2.5 flats and this point) Noticed more smoke, but the truck runs alot better. Alot brings up boost alot faster. Now on the highway I'm cruising 65-70mph at 4psi with 4-600EGTs. WOT i've seen 16-17PSI with EGTs still lower then 1000*F.

So my questions are, can a stock motor handle that kind of boost? Even if I keep my foot out of it, It will stay between 8-12 PSI. EGTs are still low enough. Should I be worried about high boost? Also I do drive the truck pretty hard, can the motor handle tapping the governor routinely?

After the winter I plan for headstuds. just need the truck for the snow.

 

I would say you are probably at the upper limit of stock headbolts, but like you say, you dont do any towing, so should be fine.

 

The wastegated Banks kits were limited to 10 PSI, but were also designed to run on 6.9s with 7/16 bolts. I suspect you can handle a bit more than that, but you still want to get studs in there for the peace of mind.
As long as the governor's in the 3600 RPM or less range, you are fine. These motors can handle running against the governor for hours on end.

That being said, you will make less power at 3600 RPM than you will at 2800RPM, so you may not be gaining anything by doing this.
I know that when attempting to accelerate as quickly as possible, I'll upshift at 3K-3200, which drops the revs into the low-mid 2K range; right in the middle of the power band.

 

Im running a R&D 90 pump with trash injectors and the Banks wastegated turbo. I have new headgaskets and new headbolts overtorqued. Wish I had done studs but the head replacement was cutting into the bank account heavily. Im peaking 16psi and I hold it there for only a few sec.at a time. Pulling I hold it 13psi and 1050deg egt. Seems somewhere we discussed high egts were harder on headgaskets than boost(respectivly reasonable amounts). Maybe Racindrummin will chime in on this one. No intention of hijacking your thread but heres a question for the gurus. What is a safe sustained Egt for headgaskets (not pistons) so they dont get cooked?

 

Thanks guys. I drove about 200 miles on the highway EGTs were under 600* most of the time at 65-75mph, peaked about 750* when really pushing it. I'll just try to keep the boost down until spring when I can get headstuds in. Hopefully, intercooler too!

 

You aren't going to get the EGTs hot unless going up a /long/ hard hill, or towing a trailer. With a turbo and engine in good tune, you have enough power to get up to speed quickly, so you just plain aren't using that much fuel/generating that much heat if you are obeying the speed limit.

 

To add to what i already said, there are plenty of 7.3s running high teens / low 20s on stock bolts with no problems. That said, blown headgaskets at the same level arent unheard of. So it really just boils down to whether or not using your full potential, is worth the possibility of changing headgaskets. If it were me id drive it like i stole it, but i like fixing things lol.

 

What is a safe sustained Egt for headgaskets (not pistons) so they dont get cooked?[/QUOTE]

900 degrees celsius, 1600 degrees Fahrenheit for the new performance reinz gasket Justin will sell after sucesfull trials. By that time your pistons are liquid.