I have a 2000 5 Speed Federal Spec with JWT Intake and Cattman Y-pipe as a my performance mods.

First Pull:
Max Power= 168.7
Max Torque= 191.6

Second Pull:
Max Power= 171.1
Max Torque= 195.3

WTF is wrong with my car. My car is missing about 30hp to the wheels. My car makes its Maximum HP at 4800rpm and stays flat till 6400rpms, when it drops sharply. I think that there is something wrong with my variable intake manifold. All the 5th gen dyno graphs I have seen make power all the way to the redline. Can anyone help me out here?? I seem to be having a similar problem like MAX_Gator is having. I will post the graph when my friend gets to scanning it.

BTW....Nealoc187 and BEJAY had a stellar day at the dyno, in sure they will be posting results ASAP.

 

Your torque is there, but I don't know what happened to the HP. 5th Gens are supposed to make peak HP right at or near redline. You lost over 40 HP (compared to stock crank numbers). You should definetly be making more than that with an intake and y-pipe.

 

Yep my car SHOULD have made its peak hp aroung redline, but instead it happened around 4850. I will post the dyno graph once my friend scans it. I dont have a clue where the missing HP is. I am begining to think there is something wrong with the Variable Intake. BTW I took my car to the track with the mods listed above last summer and could only produce a 15.3 @ 90 mph. I even let another Maxima owner take about 3 runs and he couldnt do any better.

 

Assuming you are a good 5spd driver...I'd say something is definetly wrong with your top end if you could only pull a 15.3
I got a 15.4 with my automatic GLE with only an intake (which I hope to get better at). Maybe you should let Nissan take a look at it.

 

Your variable intake runner is not working. Your car is only using it's short runner for low end power and it is not switching over to the long runner. Your car should be making right around 200 FWHP. Check to see if there are any loose or disconected plugs near your intake manifold. Most likeley the sensor that switches the runners is not working and should be replaced pronto. Your going to be in for a real shock once you get your manifold working! Right now your car is like a 4th gen with an extra 150 Lb's of dead weight

 

Actually, you've got it backwards The long runners make the lowend torque and the short runners make the topend power. Either way, his variable intake is not switching over at 4800-4900rpms like it should.

This is seems to be a new problem occuring in the variable intakes of the 5th gen. Maybe it's carbon buildup problem? I know the SHO/SVT Contour guys pull apart thier intake manifolds every 40K or so to clean out the carbon buildup on the butterflys and runners.

Dave

 

I knew that No really I did

 

Thats what I believe is wrong with my car. My peak hp occurs at around 4800 rpms and just stays pretty much flat until redline. Mt torque numbers are there, now I just gotta find whats wrong with the hp. Either way I amm gonna have a fun time getting this fixed at the dealer. They don't like me very much as it is. I am gonna go out and look at the manifold and mess around with it later on this afternoon. Is there any sensor I could disconnect to throw a CEL so I can get the dealer to seriously look into this??

 

I only have 27k miles on my car. If there is enough carbon buildup to make the Variable intake malfunction. Then that is a poor design IMO.

 

I searched for a lot of dyno posts, but only saw numbers (usually peak) posted.

I'm real curious to look at a (5th gen?) newer 3.5L 6-speed dyno chart. Stock, or one with typical bolt ons, etc.

If anybody has one posted, or a link to a thread on here with one posted, or a webpage, I would appreciate it. Thanks!

 

here's a stock 2k2 dyno....It's the only one I had the time or inclination to dig up...

https://maxima.org/forums/showthread...light=2k2+dyno

 

Also check your Y pipe flex section. It might have collapsed.

I wonder how much I'm slowin down my own car (4th gen) with my 2 15" subwoofers and stereo equipment in the back. Probably a good 130 pounds right there. The absolute worst position for a FWD car as well, especially with stock suspension.

 

I was also going to recommend you look into the condition of your y-pipe (esp flex section), but the variable intake problem sounds like a winner.