So I put in my 00vi Manifold about 5 months ago. Car is running decent, so I thought. I went to the tracks on Wednesday (15.2 @ 92.2mph) slow top end, I know. Before the manifold was put on I hit a 15.3 at 93mph. I got the RPM switch hooked up (triple checked the wires, green light kicks in). I have had a CEL since the manifold was put in.

Now the set up is a bit different than I have read (my shop made it happen).
It consist of the 5th gen UIM, 4th LIM (rotated), 5th gen TB with 5th gen IACV, 4th gen fuel rails/injectors, and EGR blocked off with a block plate. NOT TUNED (if that matters in this situation).

So after the night at the tracks, the following day I went to dyno my car to finally see the difference. I will be detailed as well. My previous dyno (mustang dyno) was done at about 70 degrees...numbers were: 173hp, 184tq. Now with the current dyno...numbers were 154hp, 163tq, A LOSS OF ABOUT 20HP!!!

Now with that said, how can I make less power but run a faster time? My wife said my driving got better, haha. But honestly, I expected to make more power than before. I have a CEL like I mentioned, only code it is throwing is the MAP sensor. Could this be the ultimate factor?

Please chime in and be harsh, I want all possibilities on the table here. I paid so much to get where I'm at and I'm going crazy! (sorry so long!)

 

Oh also!!!!......like I mentioned earlier, do I need a tune? Because at the tracks, I go to the full 7k redline, on the dyno, it taps out at 6400, everytime.

I haven't researched this either, but is the 5th gen ECU ok to use with my setup? I'm thinking no because of the injectors I'm using, but please let me know

 

arent those first numbers a bit low too?

 

was it the same dyno?

with regards to the improved time with "less power" - your driving probably got a little better.

That said, I doubt you'd be able to trap 92mph with only 154whp. I'd take that dyno number with a grain of salt. Not enough data to really come to a conclusion here. Just enough to raise more questions.

 

Can you post the dyno graphs?

The 5th gen what?

 

You need to be more clear and detailed if you want some help bro. What exact code is your car throwing?

You couldn't have lost 19 hp and 21 tq and ran a tenth faster.

Also, I would check the vias it really sounds as if its not opening up, remember regardless of the rpm switch you have to make sure the cup that turns the rod to open the valves isn't broken. The linkage is known to fail and won't open up the valves anymore check this link for details http://www.vqpower.com/v2/articles.php?article_id=21

 

In order by replies:

1) to GGenius, this may be low on a dyno to dyno comparison, (from the numbers I've seen by other Maxima's in my town, I prevail)

2) to Neal, it was the same dyno, and what more info should I provide? I'm not a noob at this, but I want to know what I should provide by your terms, would NEVER hurt my situation, just ask and I'll respond.

3) to schmellyfart, I'll put up the dyno at some point later, prolly the picture of my sheet will be taken with my phone (i peak at 5400rpms by the way)....AND the 5th gen ECU, sorry about that!

4) to Maxima king, the code is 0105, the MAP sensor, and I'll look into the "cup". Personally I dont think the hp/tq loss and time is relavent....just that I did both within two days.

 

If thats your peak on the 00vi dyno, then your vias is not working properly.

5th gen ECU is a no go, well not easily anyways. Hell, there aren't many people that swap in the ecu when doing a 3.5 swap.

 

Ok, yeah I thought so, just double checking

I'll look into my VIAS shortly...

Any idea on the code I am throwing though? A/f issue?

 

http://www.boredmder.com/ecucodes/in...1999&DTC=P0105
Check there for the code.

 

Was this on the same dyno? Different dyno's produce different results. How many runs were done?

 

As mentioned earlier, same dyno

I've done maybe about 15-20 runs overall at this dyno.

 

Even the same dyno can produce very different results, depending on time of day, if the drum was just serviced and the operator. I've done hundreds of dyno runs, albeit on race bikes, but have seen huge differences even on the same dyno. Operator is usualy the single biggest factor on results.

Additionally, can the 5th gen ECU take a new map?

 

Thanks Mac, I'll keep that in mind. However, this is a brand new dyno, I was one of the first to be dyno'd on it.

Also, when I dyno'd 173hp, this is on the stock manifold, not the 00vi. That's why I am baffled at the power loss. The manifold should have made power, but still dies off after 5400 rpms.

 

i'd like to know all the 1/4 mile times and traps (and 60' times) you ran on both trips to the track, whether or not it was the same track both times, and the atmospheric conditions both times you were at the track as well. 2 times listed without 60' and without context doesn't really tell us much since it's conceivable to see 4mph trap speed variations from extremely good to extremely bad DAs at the same track alone, let alone different tracks.

for instance I went to the track once back in the day and trapped 102mph when it was like 40-45 degrees out with a good baro. 2 weeks later it was 90 degrees at the same track with a crap baro and I couldn't break 98 or 99mph. my car didn't get slower because of something mechanically wrong with it, it was just a massive difference between the good air I had on one occasion at the track, and the bad air I had on another. the same thing can happen with dynos too.

the fact that you say your power still falls off after 5400rpm though leads me believe (without seeing the actual dyno) that your VIAS is not opening. just because the RPM switch is working does not mean the VIAS opens, unfortunately. many of us who pioneered the MEVIs back in the day learned this through much trial and error.

 

Thank you for your input, I will collect all my data needed and post it up sometime either later today or tomorrow (I need to find my previous slips)

But my runs and dyno's have always been at the same locations (San Antonio, Tx) and the weather here is dreadful, so I will definately take that into consideration. It's low altitude (I haven't checked the number though). I'll put my info up later, it's pretty consistant though, other than weather constantly changing...maybe that's a factor....hmm

 

If you are really have that much of a power loss as other people said do the VIAS fix, you could also bypass your knock sensor for a run to see if that helps at all, at least you could rule that out. If the car is running well then those are the only two things that I know that would make you loose that much power (assuming you have good compression).

 

Night at tracks before 00VI install:
60' - 2.4
1/8 - 9.9 @71mph

1/4 - 15.3 @ 92.8mph

This time was done twice that night, with the exception of my 2nd time, trap speed was 92.2mph. Temperature was around 86 degrees.

Night with 00VI install:
60' - 2.4 (Yes I need a better lauch, just fixed my clutch line, so I'm getting used to the feel) Tempature that night was around 65 degrees.

1/8 - 9.8 @ 72.2mph

1/4 - 15.2 at 92.0mph

 

Oh, btw, can anybody tell me why everytime I have dyno'd it taps out at 6400 rpms?

 

were all your other runs both nights similar trap speeds (within 1mph, or did they vary)? do you know the dates of your runs? i can look up the DA to get a real feel for how good or bad the air was on both nights (there is more that goes into it than just temp).

do you have a JWT ECU or EMU? if not, your rev limiter is 6500rpm regardless of what your tach says.

 

well if your car is the same one in your sig, i.e., 99 SE-L then thats why you cant rev past redline. im actually not sure how you got past redline to begin with. have you done an ecu swap?

as for the 00vi, sorry i cant help. but people seem pretty certain your VIAS is bad. id have to agree since its acting like a stock manifold.

 

Exactly as Neal stated, just because you have a VI, doesnt mean you can rev past 6500 unless you actually raise the rev limiter by using a JWT ecu or EMU.

 

If you dont have a stand alone ECU? I recommend one. A good tune could add 20 hp

 

Neal, the speed is within 1mph, no more than that.

The night I hit my 15.3 was July 22nd, and the most recent one was on Oct 19th.

Dreamer, it is on stock ECU...and I'll look into the VIAS once I get a chance.

Flava, when you going to come to San Antonio and hang out?!! But is looking into a different ECU/ECM necessary?

 

if youre just going by the tach then it may appear that youre approaching 7k rpms, but its really only ~6500.

as for the power loss, another possiblility is that you may have the vias wired backwards. it opens at low end, and closes at top end. (you gotta look into that, i know its possible to do on a mevi by wiring the solenoid backwards, but not sure if you can wire the 00vi actuator backwards)

 

Nah, the VIAS solenoid will open/close regardless of polarity.

OP, set the rpm switch to open the vias at a lower rpm and rev it up while the car is parked and see if the arm is actually moves.

 

Man you sound just like me after my swap. Our before and after HP numbers are almost identical too. The 00VI was the first major thing Ive ever done to my car and since then I've learned that you cant do something as drastic as changing out your intake manifold and expect huge gains without tuning your car. I went to the track countless times after my swap wondering why my times werent improving and didnt find out what it was until my friend let me borrow his JWT ecu and I instantly dropped 5 tenths off my time in one night. Find you a reflashed ecu or get a piggyback system to tune your car with and extend your rev limiter and you'll be happy. Search through some of my threads when you have some free time.

 

Tis' the reason I was on the fence of buying your extra 00vi clint. I've read too many similar threads like this about a tune.

 

You should still buy mine

 

I have an extra 00VI sitting in my garage, and ONLY live about 2 miles from him

 

Thanks for the heads up, but just so I am clear on what your saying, the tune (or reflashed ECU/JWT ECU) will fix my power loss after 5400rpms?

 

No. You still need to get to the root of why your vias isn't activating.

 

Its broken,i would be willing to bet, 99% of the time thats the case....

 

You're the one with the broken vias

Plus mine comes with stickers, +5whp

 

So I'm bringing up this old thread because I have a small question. (I just noticed this btw....) is the RPM switch supposed to show a red AND green light at all times? Or just when the the RPMs hit the approximate number?

 

which rpm switch do you use?

mine shows red until the appropriate rpm then switches to green until i shift

 

Red indicates the switch has power, green means its activating at the set rpm.

 

Ok that's what I thought, noob question I know, just wanted to make sure.

Then, why do you think the red (for power obviously) and the green for the appropriate rpm lights are always on? What I mean, from the second the car starts, the green light is on as well, at all times.

 

That's what I thought, well stated in my above post, any idea as to why the green is on at all times? Is it possible the wires I have running to VIAS in the engine are backwards?

 

any updates guys? my search still won't work from a while back