Thoughts on dyno results (1JZ)

[rxfc3s]

Hi Guys,

Took my car (mx83 1jz) down to Boostworx the other night to see where it was at in terms of power and afrs, it made 136rwkw @10psi straight off the bat, with the car dipping below 10.0 afr as soon as it was on boost (off the graph basically)
We then disconnected the FPR vac line (to stop the FPR acting like a rising rate reg) and it hit 151rwkw @ 10psi. The AFR's are still quite wavy but were at least running in the 11.5-12.0. There was no sign of leaning out.

Question is, is this power level right for 10psi? Only mods are Pod filter (no enclosure from heat tho), 2.5inch from the front pipe back to a small muffler and a GA70 stock intercooler with 2.25inch piping and i believe the ECU may have a daughterboard fitted. The car is manual.

The car pulls like a train and starts and runs fine, not laggy, blows no smoke and its never missed a beat when being thrashed.

My only thoughts are maybe the intercooler is inefficient and the intake temp is high and hurting power and maybe the AFRs still a bit too rich and hurting power.

Am i looking into it too much? Might read higher/lower on a different dyno?
I have since got my hands on a SAFC and will look into a boost controller.
What sort of power has everyone else dynoed with similar mods?

Cheers
Andrew

[JP]

my jzx81 made similar power with stock cooler/intake/exhaust and R154. Put a 3" exhaust on it from the cast Y pipe, ARE cooler with 2.5" pipe work and a big intake and it went to 198kw on the same dyno on wastegate pressure.

[oldcorollas]

We then disconnected the FPR vac line (to stop the FPR acting like a rising rate reg) and it hit 151rwkw @ 10psi. The AFR's are still quite wavy but were at least running in the 11.5-12.0. There was no sign of leaning out.

what FPR are you running?
stock FPR will use the boost reference to keep the pressure drop across the injectors constant.

if no boost ref, and base fuel pressure of 40psi, you will only have 30psi across the injectors with 10psi boost.. and less when you increase boost

[rxfc3s]

Only the factory FPR but at the moment this is disconnected and manifold nipple blocked.
This is only a temporary scenario as the car runs so rich on boost and at WOT on 10psi, the AFR's hang around 11.5-12.0. I understand what you're saying and no other mods will be done (raise boost etc) without reconnecting the reg.
I have also purchased a SAFC to help with the AFR's a bit. The FPR will definately be reconnected when this is fitted.

Andrew

[oldcorollas]

if you leave it disconnected, it would be worth checkign what the AFR's are lik when not on boost too.

what i mean is... you usually have manifold and fuel pressures like this:
(in absolute psi, ie 1atm =~ 15psi)
manifold / fuel
5 / 45
10 / 50
15 / 55
20 / 60
25 / 65

but with no boost reference, you will see
5 / 55
10 / 55
15 / 55
20 / 55
25 / 55

so if your AFR's are better when pressure is 55 instead of 65, with 10psi boost

what will happen when you have 55psi instead of 45psi fuel pressure when cruising?? O2 sensor takes care of it?

[Bananaman]

my car ran 187rwkw on 12psi ish at the last toymods dyno day, 3in exhaust, stock intercooler off? jza70? manual, and off the charts rich. Stock ecu

[rxfc3s]

Well it does seem I am a bit down on power compared to others with similair mods.
Ive spent most of the weekend checking a few things with the car. One of these things was my check engine light not working. Long story short, I got it wired in and pulled codes 14 and 52. Now i have replaced the capacitors on the ECU already and everything thing else on the board seems ok.

Basically for code 52 - (Knock sensor signal) I tried a few different things, running fresh wiring from the knock sensor to the ECU, tried replacing knock sensor etc to no avail, cannot clear this code. Occurs after the car is 'raced' past 3000rpm, basically stays on till you disconnect the battery.
Anyways, I believe if that code is logged when driving, it puts the timing into a safe area and basically retards the fuck out of the motor when it comes on boost. Thats where I think my power problem could be.
I've also tried to borrow a JZA70 ecu for testing but no luck sourcing one.

So i'm looking into a 2nd hand aftermarket ecu, for my price range I was thinking Adaptronic or Microtech LT12. Thoughts?

Cheers
Andrew

[oldcorollas]

worth checking out if your ECU has a daughterboard that affects the tune? borrow a known stock one to check?

[rxfc3s]

Yeah it does have a daughter board fitted www.sift.jp
I've had a try to source/borrow one but no luck unfortunately
I'd like to keep the factory computer, but i may be out of luck just getting one.

Cheers
Andrew