SR20 Tuning Tips/ Questions

[Moss]

Hi Guys,

I'm getting a friend who's familiar with Nistune software to help me tune my 180SX, only problem is he's more of RB30 guy, and doesn't know much about SR20s.

My setup:

KLS GT2871, SS Manifold, external 38mm WG, 3" Exhaust
Will run around 15-18psi, whatever the motor is comfortable with
Trust Pro 256/272 11.5mm cams
S15 injectors (480cc I believe)
Inbay 600x300 cooler
Stock AFM, swapping to R35 AFM in a 70mm pipe

Can anyone share some tips on tuning SR20s? I've just done an injector resize for now to get it running, but I'm not sure how to tune for the cams, or what to expect.

What are some good A/F ratios to aim for? Looking at other peoples stuff and turbo cars in general, I should be aiming for about 14.5:1 or so cruising and idle, and around 12 on boost, is that right?

What kind of timing should I be aiming for, especially with my cams?

Is there a guide on installing the R35 AFM harness? I've done a search but haven't had luck, and I have a guide from HPI Japan, but its in Japanese.

Is there any other tips or advice that SR20 savvy guys can add?

Thanks for the help!

James

[speedemon]

well the first thing il say is read read read and then read some more on this forum lol
next you A/F should be 14.5 at idle or there close when crusing it should stay in the 14's some where then under boost it should be 11.5
i have a question why so small injectors it seems to me you may run out of fuel at higher boost levels or be right at the max limit of them

[Moss]

Righto so I didn't realise that there was a section on the website with articles on basic engine tuning and also how to tune with nistune. After reading those I feel a bit more confident with what I'm doing.

I've basically figured out AFRs, pretty well due the the guides matching speeddemon and a few other peoples methods. Seems simple enough. And for the timing, just add until it runs out of torque then peg it back a bit (5 degrees seems safe?) I'll have to ask my mate if he has any knock measuring stuff. Still not sure on any special provisions for the cams, I'm hoping I can get the car running with them in there on the base tune, scaled for injectors. Should I be running more/less fuel or timing to help the car run out of their powerband? Or are they small enough that I shouldn't need to worry about them as much as I am at the moment.

As for the injectors, I'm not sure they will be enough either. Coming from the RB world, where 480cc injectors would have been fine for the expected power level, I picked the S15 stuff up real cheap, but I obviously didn't think that I'd need bigger injectors than an RB would need, simply because there are two less of them! I think I'll need to rethink other options in this area.

[skylinegtrhr]

Search Pete's - PL memberlist.php?mode=viewprofile&u=6 posts he is expert for SR20.