I'm new to the Evolution so I apologize if my question is stupid. I've read that the turbo spools to a maximum of 19 psi in stock form. Considering the WRX has 13.5 psi and the STi has like 15, 19 psi seems like an aweful lot for such a small engine. Does anyone have any concerns about the longevity of the engine pushing that much boost? I really like the Evo but this is my only apprehension.

Peter

 

19 is not even enough for that turbo... i've seen people turn up the boost to 22 psi

 

The WRX & STi are Aluminum-Alloy Blocks, the Evolution is a Cast Iron Block.

 

i think you're sort of mistaken, as i recall, your boost spikes at 19 psi and drops down to 16psi, so no you're not boosting at 19psi, you're actually boosting at 16psi. that what you're holding.

 

I am not an expert but, from what I have read, the engine is more than capable of withstanding that boost pressure. In fact, as previously mentioned, people are raising the boost pressure and also upgrading to larger turbo systems while retaining stock internals. The engine in the EVO has been around for some time and many tuners are capable of safely extracting quite a bit more power (over stock) from it.

 

adding to what ookami mentioned... aluminum alloy block is lighter but far weaker... cast iron block are bulletproof

 

If you are considering just the block, the 4G63 is very impressive and as mifesto stated pretty much bullet proof. Many DSMer's with built motors routinely run with boost in the low to mid 30 psi. You can always tell the high boosters at the track; the dipstick has been either pinched or a setscrew drilled in to keep it from blowing out of the block.

To answer you question, daily driving with peak boost at 19 or 20 psi should not change the life expectancy of your car. How you drive will make the difference.

Speedlimit...

 

19 psi is nothing for this motor. If you maintain in properly, it will last a long, long time.

 

Thanks guys. That absolutely answers my question. Damn the evo rocks!

 

I know of some people running 22 PSI to redline with a boost controller and turbo timer being their only mods. Is it healthy? I'm not sure, but I've been told 21 PSI is relatively safe.

 

Boost-Solutions.com put on 42psi on the stock block, and when they took the engine apart, no signs of detonation, everything looked clean


https://www.evolutionm.net/forums/sh...threadid=65483

 

on 91 octane 20psi, is the most you should use

 

In general if a turbocharger or supercharger is used to extract more horsepower out of a motor...a general rule of thumb is 2x horsepower (from N/A) = ~20% more engine stress...on the rods at least. So boosting a motor (if built well in the first place) will not introduce too much more stress on the internals themselves.

Other factors become more important, such as overall oil flow, tranny strength, detnoation (a really big issue) and temperature.

Yes...High boost has its 'issues' but in this day and age the technology has come far enough along to boost a motor, for some high-torque fun!

Later,

jcnel.

 

It's all relative to air fuel mixtures and egt's. I would be more concerned about the turbo's capacity before anything. Then head studs & head gasket. If you have enough fuel, intercooler or WI to keep things cool you could boost 30+ daily.... 4g63's have taken a s-load of boost over the last decade.

 

how much psi where the past evos runnin on??/
(evo 1-6)