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Thread: JWT and 25* timing

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Posts: 1-10 of 42
2010-09-28 06:03:24
#1
JWT and 25* timing
I just was made aware that my distributor should be set at 25* BTDC and not 15* BTDC.

Short story, the car runs way better than EVER. I was running 10* retarded on the distributor.

I wish JWT would have made it known to me that the particular program that they gave me requires the distributor to be set at 25* BTDC. Ben mentioned nothing about it over the phone many times I spoke to him. He did not mention it in the emails we have exchanged until this past evening. I was at work and he sent me this message...

"The base ignition timing for this program you have with the JWT C1 cams, is supposed to be set to 25 degrees BTDC at idle per the setting procedures in the factory service manual (TPS disconnected and also adjusted properly and in base mode/work support mode during the setting of the timing).

You are also supposed to see that same 25 degree value through the Nissan Consult port when you have a scanner plugged in.

If you do not have both numbers matching, then something is wrong."

After a bit of disbelief and Vadim and BenFen talking with me about this and working it out on paper before I go moving stuff around, I decided to go out and change it.

I put it into timing mode and set it to 25* BTDC, reset the self-learn mode and zero'd out the settings on my SAFC II. The car ran better than ever.

I have a detonation test where I go up a steep hill in 4th or 5th gear at arond 1000 RPM and go WOT and crawl up this hill. Not one sign of detonation. (Hess 93)

So I went out on a larger road and went to redline at WOT full load. Nothing. I did it again and again and again. THe car just ran way better than ever. This explains all of my previous problems, gripes, annoyances, nuances, etc...

Time to go back to the dyno and get more numbers.

Maybe I am an idiot but I really do not recall reading anywhere that JWT has some programs that you need to run the dizzy at 25*. A month of fuel, wasted. What a shame.

I cannot wait to get back to the dyno now.

EDIT: Added new information to stress importance of this relationship and its possible negative effects to those who want to turn there distributor around willy nilly.

The base idle timing starts at 25 degrees. Most factory ECU's start at 15*.

I, also, ran my stock ECU around 22 degrees. For the exact same reasoning ashton said

I have my distributor set around 28 degrees right now. I lost power when I had it at 32 degrees. Brought it back some more and gained nothing so I went back down to a safer 28 degrees.

Either way, whatever you do to your timing, the base idle timing that is programmed on the ECU and the physical location of the dizzy need to be in sync.

For example, my stock P.O.P JWT ECU program displayed (via nissan datascan and consult) 15 degrees of base idle ignition timing. I had my dizzy set to 15* (via timing light) and the car ran great.

When I got my JWT ECU back from them after being reprogrammed, it would display 25 degrees as the base idle ignition timing. I had no idea that the relationship between the two needed to be matched. This had me running 15* of physical timing on the distirbutor (via timing light) and the ECU was running the program set for 25*. Therefore, my timing was retarded ten degrees throughout the entire RPM range. from zero to redline.
2010-09-28 06:16:58
#2
Do they put it on the lil label on the ECU that will tell you weather to set it at 25* or 15*?
2010-09-28 06:24:33
#3


You tell me.
2010-09-28 06:34:36
#4
Well if you can do that on a Jwt ecu I am tryin it on my stock ecu, Which is alot safer. With monitoring of the AFR of course.
2010-09-28 06:44:01
#5
Hah whatttt I never knew you can't have those ECU'S in CA! GREAT!!!! haha

That's good you changed it I wonder what it's at now hp wise?!?
2010-09-28 06:45:32
#6
I ran ~22 degrees when I had my stock ECU with the same 93 octane fuel. I do not know where power truly fell off but it felt great there and never detonated on me, once.

Do what you want, but be advised. Your timing base is at 15 degrees. Mine is at 25 degrees. That is just how it is. I can most likely, indefinitely turn the dizzy a few more degrees and probably get more power out of it before I am near detonation.

If you turn your dizzy ten degrees, you could very well detonate and really do damage to your engine. I could do this because my ECU has a base idle ignition of 25 degrees. I would only turn a dizzy 2-3 degrees at a time and check for detonation if you are feeling that spicy.
2010-09-28 06:46:57
#7
Originally Posted by 92SentraSE-R


That's good you changed it I wonder what it's at now hp wise?!?


That is the fucking question of the hour. I am going to go down ASAP. My car is good to go. Maybe I will change the knock sensor or just leave it removed for the runs. I can disconnect it fairly easily. At least most easily than taking the damn bolt out.
2010-09-29 03:37:42
#8
JWT sent me an email today asking for a picture of the front label of my ecu so I sent them this.



That prompted this reply...
"I had shown your ECU label image to our engineer and he said he forgot to write the 25 degree base timing information on the outside label and he apologizes for that."

I wish they took just a second to let me know about this. Yes, it angers me that I wasted 5 weeks worth of gas and I was tormented at what was wrong with setup. Maybe its because the 196,000 miles? It was not. I am glad it did not damage my engine and that this is over with. Tabula rasa.
2010-09-29 03:47:55
#9
can u sent him mine? and see what he says?

2010-09-30 00:13:06
#10
Hell I have a JWT ecu and it doesn't say anything about timing...
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