I finnally got my Vi installed and working this weekend. I am very satisfied with the results even thought I need to get a ECU upgrade, so far I have yet to notice and loss in power from 3-4k rpm which I heard that was a common occurrence because of the VI, however I do feel a little lag between about 1K-2K. I think that is where I may have loss some power at that range I won't know for sure until I have the $$ to dyno my car and compare it to my old dyno results.

 

um....congrats thanks for letting us know

 

Congrats on your successful install. I don't 'feel' a lag at 3K RPM either... but wait until you hit the dyno. I think I was hit the hardest... I lost an average of about 10hp/15lb.ft in my midrange. But then I gained over 30hp at redline

It did affect me at the track (I THINK)... but I am yet to race in similar weather to when I ran my PB before the MEVI. Without the JWT ECU, you are in that midrange in 1st gear and also in part of 2nd. That is all out of 3 gears in the 1/4. JWT ECU is a must I think.

 

I felt some loss. the stock manifold had a surge of power in the middle of the gear (felt it most in 1st and 2nd) but the vi was smooth power throughout the whole gear instead of surging

 

MEVI actually gains a slight bit of hp and tq from 2000-3000rpms (at least mine did), but from 3000-5000rpms the MEVI lost a good bit of hp and tq. I can't remember exactly what I lost, but it was something like 10-12fwhp/fwtq (maximum). The MEVI made my torque curve nearly flat, but it did take a away a bit of the mid range punch. The reason you slow down so much without the JWT ECU is two-fold:

1) 1st gear has slightly less power and may be more prone to a little bog. In my car I noted that my 330' were noticably slower by .2 of a second which tells me my 1st gear and 2nd gear weren't as strong. When you hit 2nd, you land at around 4000rpms if I remember correctly. That means you're having to dog along from in the underpowered 4000-5000rpms. It doesn't sound like that long, but it does seem to affect the 1/4 mile. I noticed a bog on the 1-2 shift prior to the JWT ECU. A shift into 3rd should land around 4600-4700rpms which means you get stuck in the bog again. Since 3rd is longer, you accelerate 4600-5000rpms longer therefore the bog is more deterimental. Don't get me wrong about the loss of power with the MEVI alone. It's not like you're going to say "where did all my power go", but you will notice that VQ is slightly slower to react in the lower rpms.

2) The JWT gains hp and tq from 3500-7000rpms. More power is always a good thing, especially with the MEVI's lack of midrange punch. With the JWT ECU, my car drives like it did with the US-spec manifold except it doesn't have that turbo-like torque surge from 3500-3800rpms.


Dave

 

Here's my dyno:

Mods:
Blue lines: y-pipe, b-pipe (186HP, 197TQ) - Feb 2003
Red lines: y-pipe, b-pipe, JWT cone, MEVI (186HP, 180TQ) - June 2003

The USM owns the MEVI in midrange (massive loss in my case) but the MEVI gave gains of about 36HP higher at redline!!! I hope the JWT ECU can fix my midrange.

But that's still a lot of midrange to give up... the loss shows up in the 1/4 mile... but if I was to race off a roll on the highway, that loss in midrange is not a factor... MEVI truly owns then!

It is interesting to note that those dynos were performed on dynojet machines, but different ones.

 

I bet your cone intake has something to do with that, HAI never helps low-end

 

actually, on a dyno jet machine, the cone intake wouldnt hurt the low end. a CAI only has better torque because it gets power at the low speed, where a HAI doesnt get cold air until the car gets going faster, in a shop with his hood up, there would be no CAI advantage, and less piping is a better flow of air...especially when holding still

 

The good news is I don't think you lost that much power. The bad news is you've wasted money because you should NEVER DYNO ON DIFFERENT MACHINES! A dyno is a tuning tool and they ALL read a little differently it is extremely important to use the same dyno every time or you end up introducing a completely new variable. Using different dynos is a big no-no because gains/losses can not be easily compared.

Example:

Nealoc is only making something like 178fwhp with bolt-ons, MEVI, and a JWT ECU yet he's run 100mph on street tires. My Maxima made 189fwhp WITHOUT the JWT ECU (haven't dynoed with the JWT yet) and I've ran 99.5mph on street tires. We're pretty much making the power even though the dynos are saying otherwise. Different dyno read differently and comparing your numbers between machines or some other guy's dyno numbers 5 states away is meaningless.



Dave

 

well your trap speeds could have to deal with your launches, track temps and altitude right?

 

Get that JWT ECU and you will love it. I can't imagine what it would be like to go from stock ECU stock IM to JWT ECU and MEVI at the same time... the difference would be incredible.

Anyhow, I lost 17ft-lb at peak but like dave mentioned, these 2 dynos were done on different machines, in different states even, so they don't mean much. Dyno numbers only serve to throw me off. My car dynos low but still does well where it counts. At the track.

 

Yes I agree. I am now settled with the last dyno place that I have dynoed at. I've always wanted to only go to one place. The first shop here actually sold their car dyno... the second shop, where I did my non-MEVI dyno above is run by the largest moron on the planet, so I WILL NOT go there again... and now I am at the current dyno shop - my third one, and I have gone back there 3-4 times already.

Some people believe that this guy's dyno reads low, but it doesn't matter to me as long as I can get comparative results. JWT has been playing with my ECU for over 2 months now. What's the big deal with them??? I even ordered through Avalon Racing. Track season is almost over.

 

I'm not sure that even using the same dyno is all that consistent. If it is then I've got something wrong with my car. Before midpipe, catback, and ECU I made 184hp and 172 ft lb, now with those things added I made 185hp and 175 ft lb, same dyno machine.

 

it only matters if you want to have a known basis for your comparison....