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Why does big boost have such a bad stigma?

Its my understanding that it's not like the "boost" is anything scary in and of itself. Its combustion pressures that blow your engine up, not "boost". Some people think that because person A is running more boost with a turbo than person B with another turbo, yet theyre making the same power on the same engine, that person A more likely to scatter their engine, which is false, no? The byproduct of high boost is more air, and thus fuel, in the engine, plain and simple. Am I wrong with this logic?

You are correct in a sense. But the more you compress air the hotter it gets so leaves less room for error in the event of a slight lean out etc

It also comes from the dark ages of horribly inefficient turbos the just blew hot air at anymore than a hand full of boost.

I always think back to the millions of dollars car manufacturers put into things. Etc why doesn't ford use a tiny little turbo and 40psi instead of a gt35 to make 240 kws etc

Less boost means a more relaxed engine in general. Efficiency is key. I'm sure we would all like a lazy 7psi to make 500hp but the reality is we can so it's always a balance between response and power on our small engines

yet theyre making the same power on the same engine, that person A more likely to scatter their engine, which is false, no? The byproduct of high boost is more air, and thus fuel, in the engine, plain and simple. Am I wrong with this logic?

If the only thing that was different was boost you'd be perfectly correct, the issue is the higher the boost pressure the hotter the intake gas, also the higher the EGTs and hence everything is just generally hotter. Heat is the enemy as it makes detonation easier, so you need to do fancy stuff like very efficient intercoolers, water/meth injection, exotic fuels like alcohol to be able to run this kind of boost whilst still running some margin of error from detonation.

When running this close to the limit you would want to start trimming individual cylinders by using individual EGT probes etc, it starts to get expensive very fast. I doubt many (if any at all) of the guys running 35psi are just simply running an intercooler and 98 octane fuel.

Why does big boost have such a bad stigma?

Its my understanding that it's not like the "boost" is anything scary in and of itself. Its combustion pressures that blow your engine up, not "boost". Some people think that because person A is running more boost with a turbo than person B with another turbo, yet theyre making the same power on the same engine, that person A more likely to scatter their engine, which is false, no? The byproduct of high boost is more air, and thus fuel, in the engine, plain and simple. Am I wrong with this logic?

You are correct.

If the only thing that was different was boost you'd be perfectly correct, the issue is the higher the boost pressure the hotter the intake gas, also the higher the EGTs and hence everything is just generally hotter. Heat is the enemy as it makes detonation easier, so you need to do fancy stuff like very efficient intercoolers, water/meth injection, exotic fuels like alcohol to be able to run this kind of boost whilst still running some margin of error from detonation.

When running this close to the limit you would want to start trimming individual cylinders by using individual EGT probes etc, it starts to get expensive very fast. I doubt many (if any at all) of the guys running 35psi are just simply running an intercooler and 98 octane fuel.

Then it would behoove one to run a cheap simple mod like an BAT (boosted air temperature) sensor in the intake.

Here is a question...where teh hell do you find a 3 5/8" V band for theses thing?

can find 3", 3 1/2", and 4" easy.......3 5/8".....

or do you simply use a 3 1/2" unit?

Powertune have them in stock to go with the precision turbo's.

  • 3 months later...

PJ....that R34 with the stock bottom end and stock cams....what was the power at the hubs? Im presuming the dyno run is showing corrected power at the fly? Im in the UK and I want to run a single on my Forged RB26 in my R32 GTR (Stock head and cams). Im going with a T3/T4 topmount manifold and was looking at the 6262.....I want 500BHP at the hubs at no more than 25PSI.......is this gonna be do-able with the 6262? Im looking for spool compariable to uprated twins but with the ability to crack 500BHp at the wheels. What do you reccomend guys??? Exact turbo specs please?

Oh.......why all the reference to 4 Cylinder Nissan engines and even worse Toyota engines??? Surely you guys must be all running 6 cylinder RB's in the main???? Just find it a little strange as in the UK where im from there isnt a lot of skyline interest in 4 cylinder mills....its all RB26/26/30 etc.......

Cheers

Andy

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