Looks like JWT gave me a 6800rpm limiter

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Oct 21, 2003 | 05:08 PM
  #1  
I had been wondering out this for a while now. With my JWT ECU, I can only rev out to a "barely" indicated 7100rpms until I tap the rev limiter. Prior to the JWT ECU, I can remember revving out to a barely indicated 6700rpms before tapping the limiter (200rpm discrepeancy). Today I decided to do a little experiment. I took my Harlan shift light and programmed it to go off at 7000rpms. Since the Harlan picks up it's signal from the coil packs, the reading is accurate. I wound it out in 2nd and the light didn't go off even with tapping the limiter for at least one second. I reset the switch to 6900rpms and nothing. I reset it to 6800 and it went off right at an indicated 7100rpms. Factoring in the agreed upon 200-300rpm "reads high" inaccuracy of the tach and the setting of the RPM switch, it sure looks to me like JWT gave me a 6800rpms limiter instead of the 7000rpm limiter I asked for. I believe Requin6's dyno of his JWT ECU with the 7000rpm limiter shows the exact thing. I also wouldn't be surprised if the guys with the 7200rpm limiters actually have true 7000rpm limiters. I'll be dynoing soon so we'll see what the truth is. If it's anything below 7000rpms, I'm sending the ECU back with the dyno plot, a video of the operator tapping the limiter on the dyno, and demanding that JWT redo my ECU.



Dave
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Oct 21, 2003 | 05:13 PM
  #2  
Quote: I had been wondering out this for a while now. With my JWT ECU, I can only rev out to a "barely" indicated 7100rpms until I tap the rev limiter. Prior to the JWT ECU, I can remember revving out to a barely indicated 6700rpms before tapping the limiter (200rpm discrepeancy). Today I decided to do a little experiment. I took my Harlan shift light and programmed it to go off at 7000rpms. Since the Harlan picks up it's signal from the coil packs, the reading is accurate. I wound it out in 2nd and the light didn't go off even with tapping the limiter for at least one second. I reset the switch to 6900rpms and nothing. I reset it to 6800 and it went off right at an indicated 7100rpms. Factoring in the agreed upon 200-300rpm "reads high" inaccuracy of the tach and the setting of the RPM switch, it sure looks to me like JWT gave me a 6800rpms limiter instead of the 7000rpm limiter I asked for. I believe Requin6's dyno of his JWT ECU with the 7000rpm limiter shows the exact thing. I also wouldn't be surprised if the guys with the 7200rpm limiters actually have true 7000rpm limiters. I'll be dynoing soon so we'll see what the truth is. If it's anything below 7000rpms, I'm sending the ECU back with the dyno plot, a video of the operator tapping the limiter on the dyno, and demanding that JWT redo my ECU.



Dave
That really sucks. Good luck getting them to fix it if it turns out to be done wrong.
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Oct 21, 2003 | 05:14 PM
  #3  
So would this explain your 1/4 times?
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Oct 21, 2003 | 05:15 PM
  #4  
If you don't make any more power up there, why?

My JWT ecu for my 3-gen VE30DE, is noticably higher. Don't know the exact rpm but I DO know it's higher than before.
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Oct 21, 2003 | 05:50 PM
  #5  
Quote: If you don't make any more power up there, why?

My JWT ecu for my 3-gen VE30DE, is noticably higher. Don't know the exact rpm but I DO know it's higher than before.
The MEVI makes peak power at 6100rpms and power only falls off ~10% at 7000rpms. The MEVI VQ is very dependant on rev limiter shifts because the MEVI losses so much power from 3800-5000rpms. The higher you can enter each successive gear, the better.

I did another test my Harlan RPM switch that activates my MEVI. The switch is set for 5200rpms and indicator light doesn't come on until an indicated 5400-5500rpms on the tach even when I slowly bring the revs up to 5500. It's looking more an more like I've got a 6800rpm limiter.


Dave
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Oct 21, 2003 | 05:54 PM
  #6  
Quote: So would this explain your 1/4 times?
Maybe, maybe not. I know Cartest has shown the 7200rpm limiter to produce ~0.05 seconds better performance (1/2 tenth of a second). If I truely have a 6800rpm limiter, I'd bet I'm at least .1 slower than the 7200 limiter.

I always have to consider that I'm at 1100' vs some of the quicker guys that are running right near sea level. I know 1100' doesn't sound like much, but 1100' is nearly .2 and 1.5mph. Yes, it's trivial.


Dave
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Oct 21, 2003 | 06:10 PM
  #7  
d'oh That sucks, Dave

Do you still want me to do that USIM vs MEVI thing for the JWT ECU?
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Oct 21, 2003 | 07:45 PM
  #8  
You might actually have the stock limiter as I had JWT do the 7200 limit on my ecu and I watched the tach go to nearly 7500. I would just shift in fear of spinning a main bearing or something. Up at that high of an rpm it really didn't feel like it was pulling any after 6800 anyway I would just stay in it just to see how far the tach would reach. It is strange but running a supercharger at 11psi making 150hp over stock didn't seem as much of a strain on the engine as running the JWT/MEVI up to 7200 rpm. Hope you get this worked out and truthfully I sold both the ecu and mevi and with a stock ecu and a usim I love my car much more around town much torquier and I hate having to redline my car like some ricer just to get the car moving good. I think I will still get a techno ecu for the timing and fuel advantages and at $70 less than the JWT ECU and 8 less weeks.
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Oct 21, 2003 | 09:32 PM
  #9  
My limiter is 7200 as indicated by my dyno. The tach indicates about 7300 when I tap the limiter. The tracks I run at are between 600 and 800 ft asl. Dyno it and see where the dyno stops at, and make sure they run it out to the limiter.
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Oct 21, 2003 | 10:00 PM
  #10  
Quote: My limiter is 7200 as indicated by my dyno. The tach indicates about 7300 when I tap the limiter. The tracks I run at are between 600 and 800 ft asl. Dyno it and see where the dyno stops at, and make sure they run it out to the limiter.
Thanks Neal. That helps. If you're only seeing and indicated 7300rpms and you dyno has shown a 7200rpm limiter, it sounds like my ECU might be okay then seeing that my tach is indicating 7100rpm. I'll keep you posted about the dyno.


Dave
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Oct 21, 2003 | 10:06 PM
  #11  
Quote: d'oh That sucks, Dave

Do you still want me to do that USIM vs MEVI thing for the JWT ECU?
Steve-

Yes, I still want to do the Cartest with the USIM/JWT vs MEVI/JWT in the 1/4 mile. Jeff K is trying to find me his old dyno of his 96 SE that made 187fwhp/206fwhp with the JWT ECU, catback, CAI, and y-pipe. He ran 14.3@97mph with a 2.20 60' on street tires. I believe IronLung and BeJay also have similiar dynos showing 185-190fwhp/205+fwhp.


Dave
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Oct 22, 2003 | 12:26 AM
  #12  
indicated about 7150-7200.
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Oct 22, 2003 | 01:01 AM
  #13  
http://forums.maxima.org/showpost.ph...6&postcount=24
There U go.

Quote: Steve-

Yes, I still want to do the Cartest with the USIM/JWT vs MEVI/JWT in the 1/4 mile. Jeff K is trying to find me his old dyno of his 96 SE that made 187fwhp/206fwhp with the JWT ECU, catback, CAI, and y-pipe. He ran 14.3@97mph with a 2.20 60' on street tires. I believe IronLung and BeJay also have similiar dynos showing 185-190fwhp/205+fwhp.


Dave
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Oct 22, 2003 | 01:07 AM
  #14  
http://forums.maxima.org/showthread....highlight=fake

Sounds close to mine...
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Oct 22, 2003 | 05:55 AM
  #15  
Quote: http://forums.maxima.org/showpost.ph...6&postcount=24
There U go.
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Could you email it to me? SteVTEC@Maxima.org
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Oct 22, 2003 | 05:56 AM
  #16  
Quote: Steve-

Yes, I still want to do the Cartest with the USIM/JWT vs MEVI/JWT in the 1/4 mile. Jeff K is trying to find me his old dyno of his 96 SE that made 187fwhp/206fwhp with the JWT ECU, catback, CAI, and y-pipe. He ran 14.3@97mph with a 2.20 60' on street tires. I believe IronLung and BeJay also have similiar dynos showing 185-190fwhp/205+fwhp.


Dave
Cool. Because even if you didn't, I was still going to do it anyways because I'm curious myself.
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Oct 22, 2003 | 06:53 AM
  #17  
yeah my rev cut definitly came in at 6800/6900 on the dyno...but was about 7100 indicated. i could be right there with you. too bad i got it reprogrammed for 7.2k when i sent it for SC reprogram, so i guess i will never know.

--Paul
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