Thread: JWT and 25* timing

NO!

I could be wrong, but I'm pretty sure this is what JWT is doing.
They have tunes for many different combinations of parts. When tuning for large cams like C1 cams and larger you have one major problem when setting your base timing. The idle on these cams is not smooth. Likely not smooth enough to reliably time the engine while at 850 rpm and lopily idling away.

When you put the ECU into timing mode using the rain dance or a consult tool the ECU locks timing at one value. Usually 15 degrees BTDC. With large cams this amount of timing isn't going to give you an idle you can work with. So to solve the problem I think JWT just sets the timing the ECU locks to at 25 degree BTDC for tunes with large cams and the rpm target is maybe set higher as well. This way the idle smooths out and the rpm rise a bit and you can properly time the engine. You set the timing to 25 degrees and you're all set.
(I think this is similar to the way the GTi-R is timed.)

This does not mean the tune runs 10 degrees more timing everywhere! It doesn't mean you are running 25 degrees of timing at idle! It just means that's what the ECU is set for when in timing mode!

fyi; jwt uses 25* base timing on their "big cam program".
this includes the S5's and C1-C3 cams. not sure of the others. it's part of their "idle stability" programming. the target idle speed is also raised to ~900-1000rpm. i've suggested in the past on _the other forum_ that before installing big cams it helps to set the timing and idle for the big cams, before the swap. because, like Ben said, the lope of big cams makes it VERY difficult to get either right, after the swap.
(hint) if you haven't yet...you'll need to adjust the target idle speed also. since the big cam program uses ~900-1000 rpm as the target, if your's is still set at 800-850 rpm you'll get whats commonly referred to as a "hunting idle). the ecu tries to keep the engine at its programmed (in this case 900-1000) while the the physical idle adjustment is at 800-850, constantly fighting each other.
it sucks that you've been chasing ghosts this whole time. the car should run MUCH stronger now that the base timing is correct.
when you're ready, i'd suggest either a calum rt (if you can find one) or nistune.

If you had a Datascan cable you could have scanned and checked the base timing in the ECU. If you do get Nistune, it is still a good idea to get the cable and use the JWT as a base.

I did, I did not know the relationship needed to be. Now, I, do. After JWT told me this I searched and found YOU mentioned this relationship. I just never searched about it. I told people about it and no one said anything of it. I guess it is because not many people use the C series programs or something?

Either way, they did fail to mention this to me to begin with. They did not even label the sticker but they apologized for that. Oh well, it is over and done with and the car feels very strong now.



This is what I did today with the car. I did about 9 runs and these are the best three.

do you have a comparo dyno? what sort of increase did you see jumping to 25* from 15*?
supporting mods?
reason i ask is, this seems low for a C1 cam'd de. nor is it sae corrected. imho, you're missing ~20-25whp.
here's an example of two of my S5 cam'd runs.

Last time I was at the dyno place, I dropped 151 whp and 121 torque.

Just yesterday, I did one run with 20* of timing just for shits and giggles and lost 5 hp and almost 10 torque.

Everything else before that, different parts or a different JWT program were there so the car was different.

I dunno, car pulls hard that is all i know.

Whenever I get the dynos emailed to me. I can get them all in the same correction factor and all that other crap. I would guess it is 155whp using SAE?

Performance:

-Place Racing 3 inch Cold Air Intake
-95-99 Maxima MAF
-K&N High Flow Air Filter (RR-3003)
-Brian Crower stage 2 cams (264* duration, 12.06mm (.475") lift) [These cams are one-one thousandth of an inch off spec from JWT C1 cams hence me using the JWT C1 cam program]
-DNA motoring header (2.5")
-VRS stainless steel mandrel bent exhaust. 2.5" high-flow Magnaflow cat, Magnaflow 22" long resonator (4 inch body), and a 5" X 9" oval body Magnaflow muffler with a 2.5" tip.
-Prothane Motor Mounts
-NGK Copper BKR6E spark plugs
-Z32 fuel filter
-Nismo thermostat (opens at 143.6*F compared to OEM at 169.7*F)
-25 degrees BTDC base idle ignition timing as per JWT ECU specification


Electronics:

-JWT ECU (rev limit to 7700, flashed for JWT C1 cams and Maxima MAF)
-Apexi S-AFC II
-NTK Front (24521) and Rear (24024) Oxygen Sensors

now i see. you're running a jwt C1 programmed ecu with bc stage 2 cams!. disregard my earlier post about missing whp.

I can never confirm how similar the cams are or are not. They are both from Nissan billets and the specs are the same duration with the C1 cams having one-one thousandth of an inch more of lift.

That was why I picked the C1 cam program. I do not know how else the cams can be different and I will never know until I get a pair of C1 cams in my hands and I get to measure them out.