[Kponti]

What is the max RWHP that U can obtain on pump gas (93 octane with or without octane boosters) on a single turbo esp. a t-78 on a 6-spd.

I am in the process of deciding b/n the LS1 C5 and a Supra. I don't want to have to run around on race gas since it is not readily available here. I am leaning toward the T-78 turbo (looking for ~700-800RWHP) then add a nitirous oxide kit I am developing (150 shot from ~3500rpm-5000rpm then 75shot from 5000rpm onward w/o switching and bottons etc)

 

[Ranger498]

on pump gas i think its 550 -600 top !

 

[Kponti]

Thats some good info there. Keep em coming.

So all these great HP #s I am seeing on this board are with race gas??

 

[Walser]

It depends entirely on efficiency. I make 625 rwhp on pump gas, every day. I will drive down the 1/4 mile, extended hi speed runs, street races, whatever. No probs - exhaust gas temps stay reasonable. I wouldn't run full out on a road course like that, but it is perfectly tenable day-to-day. Why? Because of increased volumetric efficiency.

It's not rwhp that is the limit, as much as rwtq. Torque is directly related to cylinder pressures. If you make the same torque, but higher in the rpm band, you will make much more horsepower, but have the same strain on the motor, as far as cylinder pressure is concerned. After you have increased you volumetric ifficiency via big turbo kit, cams, intake, etc, you need to optimize cooling. These two factors addressed allow you to run high hp on pump gas.

 

[Kponti]

Ok Walser, (or anyone else) what I understand is with a T-78 (cost effective and great HP) full fuel system (injectors, twin intank & inline pumps and looking at some fuel rails and lines if available) a 3 core Fluidyne radiator, fan controls etc etc. I could run ~650-700RWHP? Oh with a very good area under the curve (very imp. IMHO). On pump gas btw

 

[AZWildcat]

Ok Walser, (or anyone else) what I understand is with a T-78 (cost effective and great HP) full fuel system (injectors, twin intank & inline pumps and looking at some fuel rails and lines if available) a 3 core Fluidyne radiator, fan controls etc etc. I could run ~650-700RWHP? Oh with a very good area under the curve (very imp. IMHO). On pump gas btw

I think you're missing Walser's point. (and well put may I add The efficency of the turbo is what really makes the difference here. The larger the turbo, the more efficent it is as a rule. (the wheel is larger so when the turbo is compressing the air, less heat is generated) There is no such "what is the max HP I can run on pump gas" question. The question is better phrased as "What kind of boost can I run on 92 octane?" The answer is it's up to you.

The concensus is 1.3-1.5 bar; that said, on my previous car I did 30+ 4th gear 1.9 bar pulls on 92. Hell, just today at the track I pegged my Apexi 2.5 bar boost gauge, though that was on VP C14 gas. At 1.35 bar, my car went 128.5mph in the quarter which is roughly 605 rwhp. Naturally, a bigger turbo will go faster at the same boost at the expense of lag and difficulty of launching.

To answer your question, can you get to 650-700 on pump gas, sure. Will it be somewhat safe? Well, given the size of the T78 and the fact most T78s I've seen in that range are overing around 2 bar, no way.