What's Needed To Run 35Psi? Rb26-25

[Ben C34]

you could probably hold 35psi with your thumb.

Ok. Don't believe me. I don't care.

[Badgaz]

bad start to the day? where did I not believe you? I just said you could hold it with your thumb lol.

[Ben C34]

Fair point.

The thumbs capability is amazing and shouldn't be underestimated. Sorry about that.

[Badgaz]

all good...i was wondering to myself how much or if increasing overlap would overcome the pressure on the valves?

[XKLABA]

The pressure on the valves is both sides, in and out, the exhaust manifold usually has more pressure then the inlet

Then that also has to do with how old and tired the springs are and what there seat pressure is

Who ever said there was no such thing as a dumb question is a dumbarse

[djr81]

This thread makes no sense. What is stopping someone running 35lb? Stage 2 cams are all that is usually needed but it also depends on the turbo map - is it a Mercator projection?

[XKLABA]

You would be suprised, it's not as easy as just keep whinding boost into it, I am currently stopped at 28psi cause at 30psi and the spark blows out due to backpressure from the turbine being to small

[Dahtone Racing]

Try keep the head on the thing as well

[discopotato03]

Yes higher poundage inlet valve springs because you have boost pressure behind the inlet valves acting on the whole area of the backs of the valves . You don't have combustion pressure on the chamber side of them as soon as they close .

More boost means greater heat and pressure and the hot/exhaust side is the half to worry about to avoid reversions and detonation . A dedicated turbocharged race engine has to be reliable when running in a supercharged state for long periods of time . OE road turbo engines are designed to use the "power boost" to get up to speed or climb the odd hill for short periods of time .

Interesting actually , restricted rally engines are often thought to have small compressor sides compared to the turbine side . This is because they are rev limited by the restrictor so have no use for large compressor wheels . The turbines are big in relation to the compressor because they have to have a survivable pressure and heat balance across the engine ie hot side vs cold side .

To make any engine survive a lot of boost for any significant length of time you need to increase the flow capacity of the hot side . Things like porting/exhaust valve size/manifolds/turbos with larger hot sides eg GT3576R/very low restriction hot side .

Actual engine cooling is important because you have to reject more heat developed by higher power outputs . Effective oil cooling / charge cooling / water cooling would be a real good idea .

The burning question is how long do you expect to be using high boost performance ?

A .

[scotty nm35]

Actual engine cooling is important because you have to reject more heat developed by higher power outputs . Effective oil cooling / charge cooling / water cooling would be a real good idea .

The burning question is how long do you expect to be using high boost performance ?

A .

^^ This.

Bolt that head down hard with some 625+ or L19's. And don't come crying if something lets go, it's bound to happen eventually. Even a popped cooler pipe makes a great mess at that pressure.

[MagicMikeZ32]

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