Hi Flowed Turbs Max Boost

[Waldo]

hey guys just wondering if anyone knew the max boost a rb20/25 high flowed turbo with steel wheel can run, does it make a differance if its the ball bearing type or bush type?

[Roy]

No one is goign to bea really abel to tell you, as hi-flow doesnt tell us anything about the turbo:(

What turbine / exhaust wheel is it running, what A/R exhaust housing? What size compressor and compressor cover???

Even then ppl would most likely be guessing.

If you really want to know then there is a relatively simple few checks you can do. Get a temp probe...a lot of cheap multemeters have them and are reasonable accurate.

So with the probe in between your turbo outlet and intercooler, start winding up boost and check the temperature of the compresses air comign out of the turbo. Best place to be doing this is on the dyno with the bonnet up where you can do numerous runs and check the temp after tweakign the boost higher lower.

Measuring the rwkws on th edyno you will soon get to a point where the car isnt making the same gains as you wind up the boost. This could be for any number of reasons, but if the temp of the compressed air starts goign thru the roof then thats an indicator that its startign to struggle.

2nd test is to drill and tap a hole in the exhaust housing. Plumb up a pressure instrument and as you wind boost into it start to monitor how much pressure is building up in the housing as you start to give it real boost. Once done remove the instrument and put a plug in the hole. You can even use that hole at a later date for an EGT so it wont cause any harm or go to waste

There are two reasonable tests that you can easily do to get a real answer.

As for bush bearing or BB turbos at high boost...no difference. But a bush bearing turbo will be more likely to wear and fail at higher boost. It doesnt mean it will, its just the design of the turbos means that if you start running big shaft rpm then wear increases, with the BB turbo being more durable.

Odds are though if you running a std engine then you wont be running to much boost and if you are keeping an eye on oil quality and temps then you should be fine

[DRIFTER]

so what would you reckon the most boost you could safely run with a brand knew garret 500hp to4 with .63 rear and .7 front on a rb 20

[R31Nismoid]

until it stops making power with each psi increase. same for any turbo save for the stocker as you get ceramic wheels to consider.

[Waldo]

so pretty much just keep uping it say until around 19 or 20psi or until it starts to struggle makin more power? a high flowed should be good to run 19, 20psi, shouldnt it?

[L 33]

When i got my turbo from gcg they told me it could ran up to 26psi, not that i would take it that high.

[B-Man]

The GCG hi-flow I had many many moons ago would make no more power past 18psi - but that could have been due to lots of things.......

Max boost doesn't really mean anything.

[Al]

Also look at your engine's capabilities, no point pumping boost up to 24psi, when you risk blowing the engine at 20psi.

[R31Nismoid]

boost wont kill a motor

tuning will

[Al]

True.......

But with boost, comes pinging, then the tunner will have to retard ignition which may make the higher boost useless.