red wrex

Just fitted a boost guage....(about time)

and the car is pushing out 13.5 psi in every gear at around 3500 revs

does this sound right for a MY94

also with a dawes and fuel cut misser outer thingy... what should i take it too

as i cant afford a complete map yet

redwrx

Ive got an my93wrx, and i normally run about 16psi for safety ...(with Dawes and Fuel cut defender only)

Im on standard ecu, with just prodrive backbox ...all other catted pipes in place

I think you can run upto about 17.5psi (roughly 1.2 bar) max


Frank

The_Judge

First of all, be very careful increasing the boost pressure on a JDM with a standard ECU. You already know about the octane difference, but don't forget the ignition timing...

To answer the question though, you could really do with the compressor map for your turbo. A few calculations and a bit of plotting later, and you'll know what the most efficient boost pressure is. You need to be careful of too high boost at too low revs/load (compressor surge, bad for your turbo), and you also need to be careful of too high boost at higher revs/load, as every turbo has a point beyond which all it's doing is increasing the inlet charge temperature (bad for your engine).

You'll be able to "feel" if you've set the boost pressure too high, as the ignition timing won't be as advanced due to the high charge temps, so the acceleration won't be as keen. Also, if it's detting, you'll notice it "bogging down". Obviously, you'll be carefully monitoring your knocklink though, to avoid that from happening...!

red wrex

"To answer the question though, you could really do with the compressor map for your turbo. A few calculations and a bit of plotting later, and you'll know what the most efficient boost pressure is"

Where would i get this from, its a TD05

The_Judge

Dunno which compressor you've got, but this'll give you an idea...

red wrex

cheers judge but looking at that i can honestly say........

what the hell does it all mean???!?!"?!!

The_Judge

This one will probably make more sense...

The figures on the left indicate Pressure Ratio (boost pressures in bar + 1, in other words, 2.0 on the scale is actually 1.0 bar)

"Surge" is anything to the left of the left-most line.

"Fan heater" is basically anything to the right of the right-most line.

For this particular example, somewhere in between 10 and 15psi would be about perfect. Or, if the owner could prevent boost of 15psi being achieved before 4000 rpm, he/she would benefit greatly further up in the rev range. This is all based on one set of figures for one particular car. As you can see, if the owner could make the car operate more efficiently, there's plenty more power available from this turbo. But another way of looking at it would be to say this turbo isn't really appropriate for that particular cars setup...