Jump to content
SAU Community

Recommended Posts

Its only my opinion but id just make sure your exhaust flows well, free up inlet tract to turbo, and be happy with the boost that it runs at this level.

Without wanting to throw on an intercooler and clean up the maps, id say running extra boost will give very little increase in power, whilst increasing wear, possibly damaging engine with high inlet temps and detonation.

Why do i think this, well prior to fitting my IC my RB20DET was no quicker when running 1 bar as opposed to leaving my AVCR off. Now even with an IC i still only run std wategate spring pressure (AVCR off) and i still get 0.85 bar.

Car does have more top end with 1 bar, but pings so i leave boost std for peace of mind until ECU gets the required attention.

As for the fuel cut, i cant help there, my old GTS-X ran an MT8 computer when i bought it, and as for the boost it ran? Well 11psi, but that was with a hybrid T3/4, so my R32 is probably a better example.

There are two problems with the standard turbo, both centred around the ceramic exhaust turbine.

Firstly, being ceramic the turbine is sweated/bonded onto the common shaft and therefore it does not like too much resistance ie; the exhaust is pushing the turbine while the compressor is trying to move air into the engine. Too much resistance (boost) and the turbine and the shaft part company.

The second problem is one of heat, the ceramic turbine will only handle a certain amount of heat coupled with this resistance. The heat builds up over several minutes of very hard driving (say on a circuit) and the turbine shatters or parts company with the shaft. Leaning out the engine to achieve more horsepower also increases the temperature of the exhaust.

So to answer your question, our experience has been that 0.9 bar (13 lbs) maybe OK for a road car as long as it is only in short bursts so that the heat does not build up. If you do any circuit work or long distance high speed stuff, then 0.7 bar (10 lbs) may well be the safe max.

The boost readings above are at the engine inlet. The boost at the turbo will of course be higher than that depending on the airflow of the intercooler and the pipework. By reducing this restriction (better intercooler) you can have more than 0.9 bar at the engine but still have the same resistance (boost) at the turbo.

With a really good intercooler and pipes we have achieved 0.8 bar (12 lbs) on a 200 RWKW road car reliably. But 5 hard laps on the circuit and the smoke escaped.

Sorry that this is a complex answer to your questions but it is a complex scenario.

I am also of the understanding that the NICS turbo isnt exactly a thing of beauty. Not Ball bearing and pretty old design turbine/compressor.

Not knowing whats done to your car or what you have planned i would suggest that you stick with freeing up the engines breathing.

As Sydney kid mentioned without tricking the wastegate actuator with bleeders etc you can get very close to the boost ceiling of the turbos.

Instead of spending $100+ on boost controller (bleeder type) you are better of with spending $350 on an old 7M-GTE (old 3L Supra) intercooler.

Cut and trial fit the piping yourself, (hassle those in the know) then rock up to your local boiler maker/welding shop with a case of beer and you bits to be welded.

Now im getting off topic... sorry

Hi Roy good to see someone else that likes the 7M-GTE intercooler, being non cross flow they fit up nice to a GTST, simple pipework. We have them making 190 rwkw without excessive air temperature. Nice and light as well.

Don't tell too many people though, the price will go up.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • It is a kunfine Android screen . Does anyone know the wirering diagram of the fuga ??
    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Awesome, thanks for sharing!
    • To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
×
×
  • Create New...