Nistune Forums

Hi guys.

Just chucked a forged engine and GT675RS turbos into the old heap. I've got it running ok and done the first few hundred miles of running in, but the idle appears to be uneven when warm - it's fine when cold. My existing tune seemed to work well with the old engine but I always felt it wasn't quite as good as it should be. I have reset K to match the new engine and tubs but left the rest of my original mapping as it was.

My question is, is there a particular base map that would be most suitable for my setup? I think it may be best if I start again. Reading some recent posts on here it seems some base maps are not a good choice for some cars. Not sure exactly what year the engine was built but the car is a 1990 Jap spec auto to manual conversion with AIV, PRVR, Carbon can, EGR, aircon removed and plenum water bypass. Additional mods made should make it good for 500BHP+

Cheers
RobH

Hi,

It would be good to know what car you have ..

I doubt there is an image which will match your moded car, you always need to tune the ECU.
So your concern is rough idle when warm?

Check your timings/mixture/idle maps.

Doh! Yes, car type may help. It's a 300ZX TT (Z32), 1990 Jap model

I know there won't be an identical map to my requirements, it's more that I've read that some base ROM images are not right for some cars/ecu's. The other grey area is whether I would be better using a manual or autobox image, and UK spec or Jap spec?? Presumably manual UK spec (?)

Cheers
H

Hi,

I'm on RB25 but browsed through many Z32 images.

Sorry I can not help with the gearbox image selection, but I recall there was a thread about this here.
The JDM images are mostly made for higher octane fuels ... (so I would try these since the timing might be more aggressive)

I bet Matt can help you out with your question.



Cheers,
Andrew

Thanks Andrew, I'm sure you're right about the aggressive maps, I used a Mines ECU from a Jap import for a few months and that really flew compared to the UK equivalent I'd been using.
Cheers
H

You can always load 2 images into the Nistune SW and click on 'compare'
That usually points you in the right direction.

MINES tunes are for 100 octane fuel. It may be pushing more timing than what fuel is available in your region.

Hi Matt, sorry, missed your reply. To clarify, it was actually a complete Mines ECU I was using for a while, not a Mines tune programmed into Nistune. I only used it for a few months but never had any problems with it and really noticed the difference.

I'm still unsure what ROM image is best to use as a starting point.

I'll have a look at comparing a few but there's no substitute for experience (preferably someone else's ;D )

K is down to the low 180's (183 I think) to get 14.7:1 at idle. This is a bit lower than on the previous engine/turbos.

Cheers
H

Would recommend using the image which matches your ECU casing for starters (which should be preprogramed into the Nistune board when received). Double check the mixtures throughout the rev range whilst monitoring for detonation. It needs to go on a dyno and tune for your desired boost settings rather than try and work from someone elses existing tune (once you got the car running with right K value for the injectors)

Ok, ta. I've had a look through all the images in the ROM pack, comparing to the image I had been using, looks like I'm using the most agressive anyway...

I am intending to set it up properly on the dyno with high boost once it's run in and I've made a couple of other changes. Seems to be ok for the time being though.

I've got a lightweight flywheel so I suspect this may have something to do with the erratic idle, perhaps the idle speed needs raising 150 rpm or so..

Cheers
H