I went and picked up my ECU today and installed after work. Removing the old ECU and installing a new one is a biatch!!! It was as if the car was built around the ECU.

Anyways I got it installed, prayed, and fired her up. She started without a hitch, but unfortunately for me, it's been raining all day and rain is expected to last thru mid-day tommorrow I knew I wouldn't be able test the setup out fully, but I just had to experience something. I got on an entrance ramp in 2nd and opened it up from 4000rpms. The tires spun a little 5000rpms, but hooked up again. I shifted at an indicated 6800rpms and shifted to 3rd nicely. The tires spun which is a bit unnerving at 70mph on a wet surface. Slow down, Dave!!! I continued down the highway in 3rd at 4500rpms and punched it. There's definately more power there. The car was hauling some booty, but I backed out at 80mph because that's as fast as I'll go on a wet surface. I got on a lone service road and layed into from 3500rpms in 2nd it started spinning around 5000rpms so I had to let off. See a pattern? I decidied just to experiment with tip-in acceleration from 3500+rpms to 5000rpms in 2nd and 3rd and there's definately more power there. The MEVI manifold now feels like the torque-rich US-spec manifold from idle to 4000rpms.

I'm pleased very pleased, I just wish I could push it harder.



Dave

 

Wow, congratulations man. It is about time you got an aftermarket ECU lol. Now, if I can just come up with the funds to get one, with my nitrous (or future turbo).....

 

 

congrats...you can now experience the full effect of the MEVI.

--Paul

 

Time to hit the track, good luck

 

Damn, you guys rock!


Make all of us 3.0 (and 4th Gen) guys proud and good luck at the track!!

 

ok, after my exhaust is the way i want it I know what I am saving up for.

 

I feel you on removing the ECU. Its not held in with bolts, just pressure. At least you don't have that giant automatic wiring harness to hold it down. My ECU is still crooked because of that.

 

Mine was held in with 2 10mm bolts plus the wiring harness connected to the ECU frame in four places. It wasn't fun.


Dave

 

Me jealous!!!!! I wish they come out with a ECU to fit the 98+. Anyways, great to hear.

 

Damn it. After reading this, I want to go with the JWT ECU. But I have a 97 automatic. I'm working on getting a nitrous setup right now for added power. But I'd rather get the ECU since you don't have to refill the ECU. And I really don't feel like paying more for a modded nitrous ECU. Decisions, decisions. Do I wait and see if JWT comes out with a 97+ ecu. 7200rpm must be nice. =(

 

Congratulations, it sounds like the MEVI is really not worth it unless you can get the raised rev limiter Good luck at the track.

Any plans to dyno? (I assume you already have a baseline) Any reason to think the midrange gains would be different on a US spec Intake manifold?

 

I have the VI w/o the raised rev limiter, although not for long. It is still worth it to have the VI by itself. It really rounds out the car. I feel like I am driving a whole different beast. This is how the car was ment to be.

 

Personally I feel the VI is not worth it for street use considering -

• It's high cost
• Low end power loss (I know it's small)
• Gains concentrated a very small RPM range
• Difficult installation

I know some (OK Most ) disagree with me, hence the - . If you (and anyone else who has one) like it then I am happy for you. The raised rev limiter makes this Mod much more attractive but it is still not for me.

 

Now that I've done both the MEVI and the JWT ECU, I believe it would be best to do the ECU first since you can take advantage of the gains. You're right in that the MEVI does little in terms of 1/4 mile performance without the ECU. My final ET/MPH didn't change at all, but the slips showed that with just the MEVI, I was slightly slower in the first 1/8 (gears 1 and 2), but after that the car was accelerating harder in the final 1/8 (3rd gear). What's this showing? At the top of 2nd and beyond, the MEVI without the ECU will out accelerate the USIM. It truely is a mod more highway fun. The way the motor feels changes completely when you install the MEVI. The motor is even smoother, the intake noise is lower, and the car just wants to rev.

I do have plans to dyno and I have dynoed multiple times. Here's the run down:

WSP y-pipe, UDP, HKS intake, B-pipe = 183fwhp/192fwtq (14.68@97.79mph)
WSP y-pipe, UDP, HKS intake, B-pipe, MEVI = 189fwhp/186fwtq (14.70@96.9mph)
WSP y-pipe, UDP, HKS intake, 2k muffler, MEVI, ECU = ?


I will probably go to the track before I get to the dyno. March 30 will be opening day at the track and my track just got completely resurfaced arty:


Dave

 

I wonder if JWT couldn't eek out a little more optimizing FOR the MEVI.

I know they optimized for the US, but maybe JWT might be able to customize further for those with MEVI and the different limiters.

 

congrats Dave... now get to the track!

between your and Neals' posts I am getting more and more frustrated about the lack of 97+ ECU....

 

You read my mind. But I think its remote that they will develop new code for variable intake people. They may say they will but it won't happen. Unless its a really quick fix that doesn't require R&D.

 

JWT's stance on everything is "The normal program will work". I tried to inquire multiple times about optimizing for MEVI or optimizing fuel and timing maps for more power. I have 94 octane available and it's well known that JWT tunes on the conservative side, the only response I ever got was "Our normal program will work fine." I just wanted to say I know it will work fine but I want MORE. I bet if they would cooperate you could squeeze another 5hp and 5ft-lb out of the ECU but who knows.

 

I'd say that's conservative especially up in the 6000-7000(7200) range, but who knows.

I can't believe JWT wouldn't allow somebody with MEVI to stop by and do some tuning. Once they determine what advance/fuel is needed for different RPMs, it would be just as easy to reprogram.

I know Turtle went by for tuning, but that didn't turn out good.

 

I got to do some real testing today. The conditions still suck, the air is drenched in humidity (100%) and there's still a nasty low pressure system lingering (pressure ultra low at 29.40), but the streets are relatively dry and the temps are nice and cool (upper 40s).

I wrapped it out in 1st and shifted at an indicated 7100rpms and barked the tires big time. Usually with my sticky 17s I only chirp the 1-2 shift and sometimes it doesn't even do that. This time it was "barrrrrrrkkkk". I didn't hit the limiter either. I know the tach is off and I estimate I had to be close (I have the 7000rpm fuel cut). When I landed in 2nd, the "soft" area was gone because:

1) My shifts land 500rpms higher landing at 4800 instead of 4300
2) The ECU has restored lost power in the midrange

Getting on the highway, I wrapped out 2nd. Again, I wound it to 7000-7100 (didn't hit the limiter). I shifted the 2-3 fairly quickly and the rpms fell back to 5000rpms and I was hauling. The car has a rush of urgency it's never had. It is very weird to see your tach deep in the redline, but the motor shows no signs of protest.

IMO, I think the ECU still needs some time to learn my car's setup. I use to think the ECU didn't do any learning, but lately I've noticed that when I reset the ECU or unplug the battery the car felt slower for the first few days. As the days wore on, the intake got louder and the acceleration became more snappy. Since the JWT ECU has sat without power for a long time, I can only assume my car may get even quicker. I've already noticed my intake is getting louder. I hope Neal can verify this also.


Dave

 

i envy all of you with the JWT ECU. I want one!

 

OH wow.. this is awesome man.. congrats on your new ECU !!
It would be interesting to see you and requin6 run side by side on the track. You two have to be the fastest NA 4th gens. NA stands for naturally aspirated AND North America ! hahaha.

 

Neal has the fastes NA 4th gen.

 

I can't wait to see the times you and Neal get at the track. Congrats! Z28 WHAT?!

 

Dave you also have the 7200 rpm rev limiter?

 

I told you guys the JWT ECU kicks ***. Also outside of running more agressive ignition timing, there shouldn't be any difference in the fuel/timing curves between MEVI and USIM. But then again we would need someone to have the A/F logged during the dyno. While having someone with a CONSULT doing a timing sweep. However I'm betting there isn't much gain in tuning because of the stock cams. Change the cams and it is a whole new ball game.

 

Nope. The gains from a 7200rpm limiter is on the order of 0.03 seconds (not tenths, hundredths). JWT told me that raising my limiter to 7200rpms could cause valve float and that they wouldn't be responsible for that damage. I decided to go with the 7000rpm program.


Dave

 

Congrats!So Dave did you check and see if you got any cel.

 

That was a primary concern of mine when I decided to go with the ECU. Ben at JWT had informed me that some of the late model 96s (like mine) might get a CEL for some EGR related equipment because of unknown conflicts with the programming. While the car would still run perfect, a constant CEL would be kind of annoying, but I could deal with it I guess. The ECU I bought was from the same exact product run as my car's OEM ECU. I'm happy to report that I have not had a CEL yet (knock on wood). I've driven my car on 8 different occassions with seat time ranging from 10-30 minutes. I would have figured if there was a problem, it would have shown itself by now.


Dave

 

Dave,
By no CEL, do you mean you pulled codes and there were none (05 05), or that the CEL is not illuminated? Just curious.

 

Like JWT would be "responsible" for ANY damage from the 7000rpm limiter or even a ECU with a normal rev limiter.

That's the biggest BS I've heard yet. Not you, from JWT.

 

In their opinion, raising the rev-limiter any higher than 7000rpms does introduce the possibility of valve float which could very deterimental to the motor. They were just saying that the 7000rpm limiter is safe and won't cause valve float. A 7200rpm limiter is riding a fine line that their not comfortable programming without putting in a clause saying they're wouldn't responsible for damage resulting from valve float.


Dave

 

ECU...nice you just wanted to put another car length on me at the track this month....


..I think I might need a chemical advantage.




Dale

 

Have you tried pulling for codes? I haven't got around to it yet...I'm just assuming a smooth install w/o a CEL showing up right away is good enuff

 

It isn't BS. I have a set of ported VG30 heads that experienced valve float on the stock ECU. All my valves were bent and I broke #2 exhaust valve in half, along with putting a hole in the piston and breaking the rocker arm in half. My problem was I held the engine in the redline for way to long during a topspeed run.

 

I know from personal experience that the 4th Gen VQ30 will float the valves right before 7500 RPM

Have you tried new valve springs or just shimming the springs by 1 or 2mm's?

 

But all other things being equal, SOHC will float valves before a DOHC because SOHC valvetrain mass is greater. This is why most high-rpm engines use a DOHC setup.






















Ouch!!!

 

Outside of my being stupid it wasn't the motor's fault. My 87 maxima appearantly has a mechanical governor that doesn't allow a 3-4 gear upshift at WOT. Before the heads + cams I could only make it to 5800-6000rpm on the tach in 3rd gear (so that was my topspeed). After I did the heads and cams I did the same test but it pulled to 6400rpm. The problem was I held it at that rpm way to long and the valves floated. Keep in mind this was on a spare set of heads I got from a junkyard, who knows how many miles were on those springs . If I would have bought stronger valve springs there wouldn't have been any problem. However that little mishap destroyed a good engine. Now I know better than hold an engine in the redline for an extended period of time. Here is a pic of where the 6500rpm rev limiter is on my tach below click and save it.
http://www.prism.gatech.edu/~gte671n...revLIMITER.jpg

 

I wasn't referring to "valve float" with the 7200rpm limiter. I was commenting that JWT would NOT be responsible FOR ANY damage that occured no matter what ECU they sell you. Their "...wouldn't be responsible for that damage." line for the 7000rpm vs. 7200rpm limiter comment was what I was calling on.

Even with the STOCK rev limiter, they wouldn't be responsible if anything was damaged.

Again, they were talking out their azz. Why they care how you kill your engine is beyond me. If you want 7200rpms or 9000rpms, it wouldn't make a difference as far as them being "responsible".