JWT vs stock ecu

Nismo87SE · 03-24-2005, 01:02 AM

I recently sent my ecu back to JWT for a reprogram so it was back to the stock ecu for me. The first thing I had to do was reset my timing and idle (15*, 750rpm) and run 87 octane (never ran that before). After that the 1st thing that jumped out at me was the ignition timing. At idle it would vary between 9-15* which I thought was odd since the JWT ecu stays at 15*. Next thing is that during part throttle closed loop acceleration I lost about 8-10* of advance and sometimes around 15-18* of advance.

Now my techtom is telling me that my FB2% is the same as it was with the JWT ecu. However on the wideband the stock ecu dips into 12.4-12.6 AFR over 6000rpm where as the JWT ecu stayed at 13.0-13.3 AFR. Did I mention the 7500rpm fuel cut takes getting used to, I have my S3 cams retarded 4* for better topend. Also the car feels pretty sluggish but that could be several factors. I had the cams set to +6 int/-4exh so that made more lowend torque from 2000-4600rpm, my cutout on the 3in exhaust was open now its capped and finally we have the difference in timing advance between ECU's.

So far I've been able to get a max of 4.63v on the MAF at fuel cut so the car does have good pull up top. I'll do some dyno runs later to compare ECU's and see just how much power I lost and maybe do some 4th or 5th gear 1600-5000rpm pulls at part throttle for compare.

JayLew · 03-24-2005, 09:54 AM

Quote:

Originally Posted by Nismo87SE

After that the 1st thing that jumped out at me was the ignition timing. At idle it would vary between 9-15* which I thought was odd since the JWT ecu stays at 15*. Next thing is that during part throttle closed loop acceleration I lost about 8-10* of advance and sometimes around 15-18* of advance.

Now my techtom is telling me that my FB2% is the same as it was with the JWT ecu. However on the wideband the stock ecu dips into 12.4-12.6 AFR over 6000rpm where as the JWT ecu stayed at 13.0-13.3 AFR.

JWT eliminates the "knock" part of your timing map (the wierd blue part with high numbers), which is probably why you had more stable timing.

Calum · 03-24-2005, 11:03 AM

No, they change the idle timing map.

Dump the rom on the JWT ecu sometime and I'll show you what they do differently. I can't post that publically for obvious reasons, sorry guys.

JayLew · 03-24-2005, 11:35 AM

Quote:

Originally Posted by Calum

No, they change the idle timing map.

Dump the rom on the JWT ecu sometime and I'll show you what they do differently. I can't post that publically for obvious reasons, sorry guys.

It was just a guess (as they do eliminate the knock part).....I was unaware that there is a separate idle map.

Calum · 03-24-2005, 11:56 AM

Yea, there are more maps for idle and starting the car than maps actually used under power, go figure.

Nismo87SE · 03-25-2005, 01:17 AM

After doing some more driving I really hate the stock ecu. The amount of timing advance that is pulled is crazy. While I do understand that its tuned for 87 octane, I'm thinking about just advancing it to 19* on 89 octane and call it a day. One thing that gets me is the sluggishness of the engine around 1600-2200rpm at 15-25% throttle. For example using 20% throttle in 1st gear then shifting at 3000rpm lands 1700-1800rpm in 2nd gear. The timing advance goes from 25-27* to 7-9* and stays there till 3000rpm where it goes to 10-11*.

My JWT ecu on the other hand would never drop below 16* at all. As a matter of fact it would've ran around 18-24* given the same conditions. Also I noticed that my injectors are running a high duty cycle as well.

coolblackser · 03-26-2005, 10:10 PM

Quote:

Originally Posted by Nismo87SE

After doing some more driving I really hate the stock ecu. The amount of timing advance that is pulled is crazy. While I do understand that its tuned for 87 octane, I'm thinking about just advancing it to 19* on 89 octane and call it a day. One thing that gets me is the sluggishness of the engine around 1600-2200rpm at 15-25% throttle. For example using 20% throttle in 1st gear then shifting at 3000rpm lands 1700-1800rpm in 2nd gear. The timing advance goes from 25-27* to 7-9* and stays there till 3000rpm where it goes to 10-11*.

My JWT ecu on the other hand would never drop below 16* at all. As a matter of fact it would've ran around 18-24* given the same conditions. Also I noticed that my injectors are running a high duty cycle as well.

I noticed the same on the 96 g20 ECU that is my 96 B14 SER. ANd I did some road runs datalogging with the COnsult stuff from Impact and Nissan Datascan 1.4. Data did indeed show a large timing rollback. Most I have seen on the MAF is 4.4 ( Hotshot WAI , Gen 6 ) I did try clocking the MAF while doing garage pulls to 7000 and found a position that picked up the MAF from 4.1 to 4.4. BTW the car is set at 17.5 base and i run 93 octane all the time. 77K on car and engine.

Milburn

eurospecs13 · 04-02-2005, 01:15 AM

what are the addresses for the idle maps?

exxd · 04-02-2005, 07:32 AM

Quote:

Originally Posted by eurospecs13

what are the addresses for the idle maps?

We dont know yet