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from 120 thru to 180 the downward line shows that it was dropping from 14.7psi down to 12psi at WOT in top gear

That's the torque curve not boost; and torque will almost always drop off in the top end as you have past the point of Max' VE (volumetric Efficiency) and rate of change of power has began to decrease i.e.torque.

Here's an example; these two print outs are of the same runs; one showing torque and the other showing boost. See how the boost is dead flat but the torque is still dropping.

CamAdjustmentsCA18detGT2871RTorqueM.jpg

CamAdjustmentsCA18detGT2871RBoostM.jpg

Edited by D_Stirls
Thats sweet Craig. and by "drove a VT Commodore" i hope you mean "watched you have sex with Megan Fox"

hahah strange night indeed. One of those only half sleeping nights. Had the laptop next to me waiting for downloads to fin all night. Hence weird dreams.

I only really remember you being in my front yard. drinking. then kicking the wheel of your commodore with your foot.

I woke up today and thought to myself 'wtf'

i can't see how unless they are rated higher. First i would look at whether the factory solenoid is still in line if it is then bypass it and it MAY help a bit. But the others are right a EBC is your best bet as they minimise wastegate creep and do a much better job at controlling boost.

If you twist my arm i might even sell you my new one that has only done 500km since i'm looking and changing to a Turbosmart E-Boost 2.

P.S> so is your car Auto or Manual?

Its a Blitz DSBC Spec S.

BLITZDualSBCspecS.jpg

That power is low then since your car is a manual.

you should be pulling a lot better numbers than that graph of my mates, because the only mods done to it were; Full 3 inch exhaust and FMIC, that's it. Doesn't even have a boost controller, Hence the boost curve . So it's running standard factory fuel and ignition maps it's just with the freed up exhaust and intercooler they run up to 12psi.

So even on 10.5 psi you should be closer to 200kw than you are.

Edited by D_Stirls

yeah stirls, I know its a torque curve, ... being my car and all the tunes etc I just happen to know at that point of time with that tune the boost dropped off as described

alls good now tho

:D

the only mods done to it were; Full 3 inch exhaust and FMIC, that's it. Doesn't even have a boost controller, Hence the boost curve . So it's running standard factory fuel and ignition maps it's just with the freed up exhaust and intercooler they run up to 12psi.

So if I were to put a FMIC on my car which is stock except for the 3" turbo back, I could go to 10 psi without any other supporting mods?

So if I were to put a FMIC on my car which is stock except for the 3" turbo back, I could go to 10 psi without any other supporting mods?

with his car that is what we found, though every car is different and if you have a look at the graph it's a far from ideal boost curve.

Also before you go out and start flogging around with your new found power is't probably a good idea it chuck it on the dyno and run it up to see if the AFR's are acceptable in your case. Nissans are generally VERY rich under boost though.

Edited by D_Stirls

I'm not interested in huge power figures and 'flogging' it but just want a little more acceleration. At the moment it hits the factory 5psi by around 3K RPM since the AM split dump and Cat have gone on, just want a gentle extra shove so to speak. I haven't done the hi boost mode mod to the car yet either.

FMIC, full 3" exhaust, I'd put 12psi through a RB25 anyday providing your injectors and fuel pump are in good enough to keep up which unless you have a good ear for pinging even sometimes you can't hear it I would do it all on a dyno so you can watch A/F ratos through out rev range and accurate manifold pressures (boost pressure).

FMIC, full 3" exhaust, I'd put 12psi through a RB25 anyday providing your injectors and fuel pump are in good enough to keep up which unless you have a good ear for pinging even sometimes you can't hear it I would do it all on a dyno so you can watch A/F ratos through out rev range and accurate manifold pressures (boost pressure).

Yeah, i only tuned it to 10.5psi to increase the life of the turbo. 12psi is at peak efficiency for a stock rb25 turbo.

Okay you know how sometimes you see car accidents and you think... how??

Well this afternoon, there was an accident in my suburb, which resulted in a Commodore suffering rear end damage next to a bent power pole. Sounds straightforward huh? But there was a car trailer with a car on it, upside down behind the Commodore - as in right behind - but the Commodore was on 4 wheels. Hope everyone was ok.

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