After almost a year of driving with the JWT ecu, I feel like I can offer up some comments based on my experiences.

First, I'll describe my setup:

V1 blower and kit
3" pulley ==> 11.5 psi at 7000 rpm
370 cc/min injectors, brand new when installed
Z32 maf, bought used
MEVI and Pathfinder throttle body
Warpspeed y-pipe, test pipe, Stillen b, stock 4th gen muffler
93 octane Chevron only

My ecu was programmed for the Z32 maf and injectors, and a 7200 rpm fuel cut.
I did not do a before and after dyno. I intended to, but the best laid plans of mice and men gang aft agley, as Robert Burns has said.

Unimportant but interesting stuff first:
1. The continuous CEL I got due to running a test pipe is gone. Maybe JWT did something to keep the 0707 code from triggering?
2. But I get a continuous 1005 (egr vacuum solenoid valve) ghost code. The CEL doesn't light up, but the code is always there when I check for codes. I have replaced the solenoid valve and every thing else about my EGR system seems to be operating correctly. Furthermore, I get the code immediately after clearing the ecu and turning the ignition back on, which indicates it may be a wiring problem, BUT I do not get the code when I reinstall a spare 5 speed ecu I have. I think it must be a programming bug. Iansw gets the same code with his JWT ecu, I believe.

First impressions:
1. I had problems at first due to having the maf in the unpressurized side but too close to the blower inlet and the recirculation hose from the bov. Backflow from the blower and the bov was sensed by the maf, resulting in exceedingly rich afr during shifts and when decelerating. I could see my injector duty cycle meter light up everytime I let off the throttle. I ended up completely fouling a set of plugs within a few hundred miles. The problem was corrected by moving the maf back to the charged side, even though JWT recommends against this. I have been running this way for 9 months without any problem whatever to the maf.
2. The ecu pulls harder in midrange than the stock ecu. How much harder I don't know, since I didn't do a before and after dyno.
3. I did dyno after installing the ecu. I got 285 hp/240 tq, but the dyno operator only took it up to about 6600 rpm. The wideband O2 indicated the afr was at about 13.1:1 at 5700 rpm and beyond. We used the SAFC to lower to 12.5:1. I called JWT about this and I was told that dyno widebands are notoriously inaccurate, especially the tail pipe sniffers. I bought a wideband O2 sensor and mounted it in my test pipe and came up with the same results as the dyno wideband. I have sinced zeroed out the correction factors in the SAFC and I am using a Cartech fmu to lower the afr to 11.5:1 after 5500 rpm. How did JWT end up being so far off (I was told they would program for 11.5:1)? I guess they are still figuring the VQ engine out. After all is said and done, though, I like being able to adjust afr myself, which I might not have been able to do if they had actually hit 11.5:1.

Incidentally, JWT is absolutely dead set against using the SAFC for corrections. They maintain that it screws up timing, since the timing maps are referenced to maf voltage and throttle position.

Long term impressions:
1. Overall, I am pleased with the JWT ecu, if only for the 7200 rpm fuel cut. With the MEVI and PF throttle body, the engine really comes alive at high rpm, and its good to have more than just 1000 rpm left after the MEVI opens.
2. Driveability under NA conditions is great, except for item 4 below. No hesitation, no bogging.
3. I have not detected any detonation at high rpm and WOT.
4. On hot days after the engine is heat soaked, I get light to medium pinging under partial throttle acceleration, especially when climbing a hill or when just barely boosting. My wideband O2 is showing an afr of 16:1 under these conditions. A lean afr is good for power, but I think the timing may be a bit too aggressive under these conditions. But when the air is cool and the engine isn't hot, the power and responsiveness at partial throttle is great, so I am loath to have JWT pull timing. I think maybe the J&S Safeguard is a good solution in this case. The pinging goes away as the afr lowers and the timing is pulled when I floor it.

 

NICE feedback~! You've been a great asset here and keep it coming. Dyno that bad boy ALREADY.

Also, that light to medium pinging is "okay" IMO, however my bet is that your charge temperature is too high for your 93-octane. High loads and low RPM up to the peak torque are prone for detonation especially. A way to enrich the mixture with fast TPS changes no matter what RPM would be a nice way to combat the detonation(JWT should be able to fix that~!). An intercooler could be an option to raise the point at which your detonation occurs, but you have to weigh the benefit-to-costs.

Does it occur at any speed or just lower speeds? How about at higher speeds, but lugging it in say 5th gear?

One thing you might try is to determine if there is a TPS % that this occurs above, say 30% or more, and then use your low/high SAFC threshold setting to toss in some extra fuel in that region only. However, we know that also indirectly adds advance, so it might get worse.

I've got the same light throttle detonation problem on my POS Sentra especially anytime it gets hot out with 91-octane fuel. Nissan even released a TSB for it with a countermeasure MAF for areas over 100*F. I'm looking for a cheap AFC to attempt to solve this issue rather then cough up $300+ for the new MAF.

BTW, 150K+ miles and she's still chugging along somewhat, so Nissans' can handle a decent amount of detonation...at least NA.

 

Oh...btw welcome aboard.

 

So all in all you would recommend a JWT setup ??

-matt

 

so did rich it out to 11.5:1 or 12:1 result in no more detonation?


did you just end up using the cartech's ability to add pressure at higher rpm's only?

what FP's are you seeing since the ecu install vs. the cartech only method?

how many hp did it feel like on the "butt" dyno after the chip install?

 

Thanks for the compliments. I'm going to dyno again this fall. I'm just about to make some changes to the intake path that should result in cooler air without resorting to an intercooler. I'll post results next week, probably.

The pinging occurs mainly in higher gears (but it will do it in second and third if it is hot enough) and at throttle settings below 50-60%. Above 60% and the ecu starts to enrich the afr and/or starts to pull timing and the pinging goes away.

 

I would recommend it. The raised redline is great, and the increased torque (as far my butt dyno can tell) is nice, too. The pinging at partial throttle is annoying but isn't serious, and it only happens in hot weather anyway.

 

couldn't you just run the cartech to add a very tiny bit of fuel all over the rpm band to get rid of the pinging? and then adjust it to add even more when the mevi opens...so you don't turn lean...??

or is this something that should be addressed to JWT when they program the chip and thus it will be corrected hopefully...

 

What causes the pinging ??

 

I have played around with the Cartech and done exactly that, but I haven't gotten it to the point where all pinging is eliminated. JWT could probably program it out completely with some timing changes, but then cold weather performance would suffer.

Matty - the pinging is caused by a lean condition along with hot intake air and combustion chamber, and timing that may be a little too far advanced.

 

Stephen... u da man...great info on the write up like I always said B4 u guys are awesome with with your shared knowledge...to recap on the heat soak...how much difference would it be if you put water injection..I got it but too lazt to install and don't drive too much to even consider... since are talkin about heat soak and such
thanx stephen

 

so just call jwt you think and tell them to back off on the timing slightly and also program a richer A/F then they gave you would work?

 

wait, i know i didnt read what u said correctly but i'm surprised u only got 285 hp when u have mevi and path throttle body AND pushing 11.5 psi. I thought i would be at 300 @ the wheels with my 10-11 psi and mevi and NO jwt ecu but now i see thats impossible....

 

I thought 10psi and 5spd tranny with full exhaust and intake would make around 300@wheels before jwt ecu and dyno tuning and mevi and headers....atleast that's what I thought....wouldn't 11.5 psi, jwt ecu, mevi, and dyno tuned, would put down about 350@wheels I would think....

 

i know brian v was putting down 290 before mevi and before jwt ecu and before dyno tuning...he just used the crappy vortech 8:1 disk...and 3.125 pulley on a 5spd with full exhaust and a custom cai...

 

Yeah, I was a little disappointed about that, I was expecting 300. There are a few extenuating factors, though. First, the dyno operator only took it up to 6550 rpm. The V1 makes about 10 psi at that rpm with a 3" pulley (at least mine does). My test pipe at the time was only 2.25" diameter, and I was running the stock 4th gen muffler, so my exhaust was choked at high rpm. I believe that is the real culprit.

 

Another thing I should point out is that I don't think anybody that knows is under the illusion that you will get the absolutely most powerful setup with the JWT ecu, and I didn't choose based on that. What you will get (aside from the extended rev limit, which is icing on the cake) is a fuel management system that, overall, delivers excellent driveability across the power band and is pretty much worry free.

The fact that I get pinging under certain and infrequent circumstances just means that they tried to get as close as they could to optimizing partial throttle performance, and that doesn't really bother me. Like I said, that just means more power when the weather isn't hot.

 

Here's an overlay of my dyno with a dyno of Jay25's when he was supercharged to 10 psi. He had a full catback exhaust at the time, I believe. You can see that I am clearly making more torque in the midrange (almost 25 ft-lbs at 4 krpm), thanks to the JWT ecu, and that I start to get choked from my restrictive exhaust at about where the MEVI opens at 5200 rpm. (Makes me wonder if my MEVI did open???) My dyno is the thin black lines, Jaime's is the thick blue lines.

 

I believe it did open, since torque doesn't plummet like the dynos I've seen with a broken MEVI.

 

Yes, that's what happens with NA engines when the mevi doesn't open. But the torque of a supercharged engine without mevi doesn't drop after 5000 rpm, it just levels off. Take mardigrasmax's comparison of mevi open and mevi closed, for instance. His mevi closed dyno looks exactly like mine, although he still manages to get to 300 hp.

http://members.verizon.net/~vze4yqyk/NitrousDyno.htm

 

You're right......

 

That is pretty much why I am choosing to go the JWT route...I am set in my mind that JWT has the most worry free fuel managment with plug and play performance that is very solid and that is said after researching this forum for a good 4-5 months

-matt

 

I agree about the exhaust. It's killing your HP/TQ.

Is there another dyno you did that same day that looks different? Like the MEVI opening?

 

I did three in a row, they all look the same. But as I recall, I was going through some funkiness with the Harlan switch and relay at that time. I had a loose connection at the relay, which I discovered a couple of weeks after the dyno.