Thinking about doing a cheap 5.3 built for my LS1 car in the future with a 76mm turbo. I am not set on the 5.3 part of it, as I am also contemplating an LQ build. At either conclusion I would like to push the 76mm to its max with pump gas and meth injection. I don't have a problem with running a lower CR like 8.8:1 or maybe 9:1 but would like to stay away from race gas or running E85.

My question is, will I safely be able to push something like that to its max boost and still be away from detonation? Or will race gas be needed to see what it will max out at?

 

so many variables play a part in that... im on 19lbs 9.9 to one stock 5.3 ly5 ..mpt 76mm ...running pump gas and dual meth ports.. .. 10gph and 3gph.. im bout to be upgrading turbo ,and run 10gph and 14gph .. just keep th iats down as much as possible. i see 105* on 17lbs . A2A intercooler

 

So maybe a better more specific question; what is the most boost a 76mm turbo is cabable of? Could theoretically that boost level be achieved with a large intercooler and meth injection and staying with pump gas?

 

i have been almost 154mph at a little over 3600lbs with straight 93 and a dual nozzle meth kit

 

yeah i was just gunna say we can tell you how hard we have pushed our combinations but there is no general rule of thumb when you get on a dyno or make it to the track and see your temps and everything else thats when you will see what its capable of...

i went 138mph with a stock 4.8 and a cam, 22lbs of boost, 12deg of timing, 125shot of nitrous, pump gas and dual meth nozzle, and my converter was being pushed to the moon. so i was loosing alot through it.

my inlet temps were very low because of nitrous and methanol together, something like 88deg at the end of the track, on a 90deg day lol.

 

What engine, turbo setup was that on??

 

the most boost? that comes down to another question, what was it designed to run.

40-50lbs or so haha

here is what i know, most people start to lift heads in the 20-25psi range while hitting a setup hard with timing.

on pumpgas, methanol i broke cyl7 on 22lbs of boost pumpgas, methanol, 15 deg of timing, with a 125 shot of nitrous, on a 13.0 air fuel, with a tr6 plug

swapped to a BR7EF plug (Recessed tip) and went down to 12deg, and hit it just as hard and it didnt break.

ide say stay conservative with your timing and you can maybe see 25lbs or more? on a 76mm setup?

ive seen people lift a head (stock bolts) on 23lbs on a 6.0 and e85 non intercooled.

honestly its hard to say how much boost, because lifting the head comes from cyl presssure. and that usually is a result of how much timing you have in there too.

on top of that this is all relative to how good your pumpgas is, what elevation you are at and how the weather is in a day... lol

in short ill summarize with, mild build, 93 +meth, should be able to see 20lbs all the time on a tune up that wont kill it, because my friends truck has seen 10k miles on a 20psi setup and it goes 10s 4700lbs

and the only reason we start the truck is to kick the **** out of it.
absolutely never driven nicely lol

 

370 with a pt88 on 19psi

 

What kinda power is that on the ground

 

The motor will be fully built, so they won't be stock head bolts.

How much boost will a 76mm Turbo make? I don't know. I was hoping someone in here could chime in. I am guessing it depends on your setup, but I would think that number would be some kind of range someone could give me. Then I was hoping to find out if that boost amount could be attained on meth and 93 octane.