Very Dissapointing dyno result 1uz + gt42r

[millsi]

jp, out of my league unfortunately, as much as i like tinkering, i really dont want to fuck things up.

[beerhead]

I reakon NME308 and chuckster is on the money. The A/R on such a big turbo means that you're not even getting close to the efficiency point of the turbo yet, it's just pushing shit up hill until it really winds up. I haven't heard of many stock ignition systems breaking down so low. I've got a few mates that play with worked J motors 500- 800hp and all of them hate iridium plugs, a fresh copper plug with a tight gap has a nicer spark and doesn't fowl as easily according to them, and they've been boosting motors longer than I've been into cars...

[beerhead]

Ooh forget to add - Doug's 2JZ with a GT4288 journal turbo in an S13 (build thread somewhere on the forum) . Was only making 240hpatw on 8psi on a dyno day and 580hpatw on 16psi once tuned properly. I just had the turbo rebuilt for him and we'll see how it goes on a girdled forged 2JZ with 288 cams and porting within the week.

[millsi]

plugs were brand new copper gapped to 0.6mm

[beerhead]

Dude read you thread and it looks like you haven't cut many corners, I bet you add a fat ignition system and get that turbo pumping at its efficiency point you will have a smile on your face. Hope those calipers I found for you were useable, owe you beer if they were had it !

[millsi]

yeah cheers beer, they took a bit to free up but seem to be working ok.

new ignition will have to wait till next year

[slomx83]

hey mate just wondering if you know the specs on your gt42? i believe a 1.01 exhaust housing is well suited to a 1uz

[millsi]

1.05 10 char

[Casino Kid]

hey mate i could be completely wrong but ,i wouldn't discount the auto giving a odd reading on the dyno.when you start changing autos from stock (high stall and such) they can start to give crazy low power stats (like up to 100hp less). i have seen on many occasions where fire breathing 8 sec drag cars make suff all power on the dyno.

[millsi]

Fuckn POS

After doing valve springs, hg's (with arp studs), had it on the dyno today and no ,if very little change at all.

This time though i got the data logging

It seems to have a problem going lean around 4500, it then misses but afr's go back to normal after that.
Doesnt do it on 10 psi


Still doesnt explain the lack of power though

I have the data logs but they are .elg files and i dont have the program to open them, if anyone can help with some id then i can email them.

I am seriously at my wits end with this fucking thing

[thechuckster]

can you post the fuel & spark maps?

no audible missing during the ramp up?

AFRs bouncing around like that (assuming this is picking up the AFRs in the dump pump not way out the back where it could be pickup up atmo oxygen) do suggest a fuel issue (FPR, pump, inj map, inj opening times, etc) and/or spark breakdown of some sort (still). I'll re-read the build thread to see what hardware you have...

It (the ECU) is not trying to do something silly like close-loop AFR control during acceleration?


edit: am happy to look at log files, am sitting in from a computer anyway so any work-avoidance is welcome.

[JZA70 R]

^ this...

also who is the tuner?

[millsi]

edit......

[mullett]

260Hp before the turbo is a pretty decent figure, what had been done at that stage?

As far as the current tune looks, what was with the 380HP run? Seems like it wanted to pull...Toss some bigger injectors in and run it up to 18psi?

-RM

[millsi]

Well a person in the know has just pointed out something that may or may not have been obvious, but looks very likely to be the problem.