Nistune Forums

The car:

Nissan 240sx:
RB30 w/ RB25DE head
Holset HX35 7blade (somewhere between a GT30 and GT35 .8ar turbine-ish)
DW 740 cc inj
Z32 MAF

I started with the RB20 map as a baseline. Ive tweaked fuel and timing somewhat to be very safe but I'm done being safe and I want to make some power lol. I've got my AFRs somewhat decent as you can see from the log. But it seems very sluggish... Like barely faster than my stock RB20 was. I'm thinking spool up needs some major work. Should timing slowly decrease as boost increases past atmospheric? Same with AFRS? or should afrs just dump right away?

Try to take it easy on me after looking at these lol. The log is a WOT pull in 3rd. Aux1 is a map sensor i have hooked up.

Do you have a widw band O2 ? This is a must to do what you want to do. If so PM me and I'll tell you what I learned with my RB26DETT

Of course I do... Who using Nistune doesnt :p

That actually doesn't look too bad to me. If I'm reading things right it needs to be leaned out though. I'm seeing richer than 11:1 across most of it. You want it closer to 12:1.

PL

Thanks PL.

Yeah I agree. Fuel needs to come out. I'm running low 10s in spots .

Also, I'm looking for more responsiveness in the boost transition area. Most tunes I've seen take a slight drop in AFRs when it goes over atmospheric, then gradually falls to 11.5~12 when max boost hits. Is that correct? How much power is gained by leaning it out? How does timing work in transition?

I think you'll find it cleans right up when you lean it out. You should see 14.7:1 at cruise and then it should go to around 13:1 as you approach 0 psi and then quickly move to 12:1 or so as boost hits.

These are just rough figures - some guys run a bit richer, some leaner. Either way you need to adjust your timing to suit. Richer mixtures will usually allow a bit more timing and vice versa.

Main thing is that it's going to 11.5 - 12:1 when on boost. From there adjust your boost to where you wish to run it and check AFR's again. You may need to adjust your load scales if you increased your boost.

Once that's all good then you can mess about with boost transition mixtures and timing values.

PL