Nistune Forums

Hi everyone,
I recently had Nistune installed and started to find my way around the software.
I have some pretty basic questions I hope someone can help me with.

The car is a 2001 Nissan 200sx S15. FMIC, pod, 040 fuel pump, blitz bov plumbed back and boost at 12psi.
Pretty tame, standard setup.

From day one of owning this car I have the problem that after driving the car for a while it starts to pop in the exhaust on low speed gear changes, but it doesn't do this when cold.
Is this tune related ? The bov spring looks like it has been wound in tight and I get flutter at low rpm changes so could this be an over fueling condition ?

I found post Nistune that I had a 34 knock sensor error. The car constantly ran on the knock timing map but not the knock fuel map. Should Nistune switch to both the knock timing and fuel maps when it senses knock ?

I fitted a new knock sensor (awful job), cleared the codes and all was driving well until it started using the knock timing map again. Not the knock fuel map. It was a high "teen" temperature day and I wasn't thrashing the car. Could I really have knock ?

I opened up the knock warning panel and it made a constant knocking sound. Is this meant to be the knock from the engine ? Is it reliable on the SR20 or should I just forget it ?

Sorry for the very basic questions.

Thanks,

Peter

Use the latest 0.12.11 version which will highlight both maps (was a glitch in previous versions). It is concerning that it keeps on moving to the knock maps all the time

Log the MAF voltage and AFRs if possible in stream mode and post those here. The pop may be from air vented from the BOV entering the MAF due to the angle of the piping (some air entering the MAF backwards)

Thanks Matt,
I upgraded my version of Nistune and it looks to be highlighting the correct map now.
With regards to the knock warning panel, I obviously wasnt paying attention and it was just the o2 selected under the warnings. I see that the knock feature is not available in Nistune.
I need to get my wideband conencted before I can take any meaningful logs.

Thanks,

Peter

Hi Peter,

I've found the knock sensing on S15's to be quite unreliable. From the very first one I tuned! My mate had a totally standard one with well under 100,000 km on it. Got it on the dyno and it was running on the knock maps. Made 100rwkw!

For some reasons the S15's seem to be particularly prone to knock sensor problems. I've seen it too many times now. Some are OK, many are not. As it's only a mechanism for checking if the owner has filled the tank with the wrong fuel I have no problem disabling it. It's not like it'll save your engine if it detonates at 4500rpm. It won't - the ECU only looks at knock input relatively low in the rpm range.

Knock sensor signal can be ignored by unchecking it in the flags section. But if it's raised a knock fault code then you need to physically disable it by unplugging the knock sensor and fitting a 470 or 560kohm resistor across the knock input. Which is easily done at the knock sensor connector on top of the inlet manifold.

S15's tune up great. Just don't get greedy with boost. Keep it around 14 to 15 psi and then tune IGN and fuel maps to suit. A good one will just touch 200rwkw (on DD dyno).

PL

Hi PL,
Thanks for all the info. Your posts are very interesting and I've learnt a lot from reading through them.
Might have to to fly you to Perth for some tuition !

I haven't started actually tuning, just familiarising myself with the software. I logged a 3rd gear pull on the weekend to put into Virtual Dyno and have attached the results.
Does that look normal for a stock tune? It just seems very flat in the higher rev range. The car is basically stock apart from full turbo back exhaust, pod, fmic, 040 pump and 12.5psi
I tried a few different logs and they all produced roughly the same graph.

Will leaning out the afr's allow it to build more power and not be so flat ?

Thanks,

Peter

VFRegal wrote:Hi everyone,

From day one of owning this car I have the problem that after driving the car for a while it starts to pop in the exhaust on low speed gear changes, but it doesn't do this when cold.

I think this is normal, when you put blowoff instead of oem dv - even on almost stock ones.
Got the same, on 3-4 s14, s14a.
A little pops at exhaust when changing gears at low rpms, 2000-3000, and low loads (-0,5 to -0,1 bar).

With a stock turbo torque will tend to peak early and then taper off. Particularly if you try to push the boost a bit and get a peak up front with boost dropping off after that. Usually the shape of the torque curve will be the same as the shape of the boost curve.

To this end keeping boost between about 12 and 15 psi usually works best. They're usually not particularly sensitive to AFR's but they are very sensitive to IGN timing.

I'll try uploading a dyno plot from a stock S14 that I did once. The S14/15's tune up great with just the standard turbo/inj/AFM. Nice wide torque curve. Good boost response. But turbo/inj/AFM all max out around 200rwkw, so it's easy to tune them for a great result without spending big $$$ on upgraded hardware but it hurts a bit when you wanna take the next step as you then need to upgrade all 3 items!

I have a good dyno plot of a stock S15 tune but I've tried twice to upload it and everything just locks up and craps itself, so I've given up on that idea.

PL

I thought I would update this thread a little bit.
I had a chance to spend a little time on the tune today.
I only had time to do some changes at home then go test in the car.
Focussing on the rich on boost areas I reduced the cell values down by a small amount.
I am waiting on some knock sensing gear in the mail so didn't want to play too much with the timing.
So I just used the JDM timing maps as a bit of an increase.
According to virtual dyno I picked up 19kw which is pretty cool. It didn't feel restricted up top like previous either. Pulled a lot better.
Next step is to bring the afr's up to around 11.5 and try and get the afrs a bit smoother.
I also tried to wind the boost up a bit more but at 13.5 psi it started to pop and splutter so I think some new colder plugs and a smaller gap are in order.



Being that this is not a daily driver, I bought this car just for track work, would it be worth looking at the lower rpm / load range or just leaving it as is ?

Any comments appreciated !
Cheers,

Here are those graphs. S14 with T28. It also had bigger injectors and AFM but they really don't matter for what we're looking at here.

PL

Thanks PL, much appreciated.