http://forums.maxima.org/showthread....51#post3026751

I know we don't have 3.5 VQs, but I found this post very interesting and imformative about the gains of headers over an aftermarket y-pipe that's far more restrictive than our aftermarket y-pipes due to the precats being left in place. The y-pipe vs header dyno was done on the same car. If the 3.0 VQ behaves anything like the 3.5, it looks the headers do make some gains, but you won't really be able to exploit it on the track.

 

you can get wsp y-pipe for $160 and cattman headers are what $700 -$650 or so and idk how much the hotshot are but I can't justify paying that much more money for headers and maybe 5 hp over a normal mandrel y-pipe if you are lucky. Our stock exhaust manifolds for the 3.0 are fine for most people. Well if you have a 99-01 which the y-pipe doesn't get rid of the front precat you might possibly gain more. I could possibly understand for forced induction but then you should get 3" exhaust and they don't make 3" headers for the maxima.

 

Right. Having 3" headers isn't that good from what I heard. Hell my buddy's dad has 1.75" headers on his GTO. Our headers are under 2" and the y-pipe is only 2" until the flex section.

 

The engine is completely different (VI/intake manifold/etc design). I dont see that graph helping 4th gens out much at all

 

But the Y-pipe curve and header curve are from two different cars. Could be more gains, could be less.

 

How about with rasied rev limits?

 

It doesn't matter because the headers aren't making anymore power after 6300rpms than the y-pipe.

The graph is for the same Maxima, y-pipe vs headers. The "stock" dyno was a different car.


One of these days someone will do a before and after dyno The more I read about headers, the more information I read that says full long tube headers are the way to go. Unfortunately neither the Cattman or Hotshot headers are a longtube design. I know that on the 5.0 and 4.6 Mustang, people are told not to waste their time with shorty style headers because the gains are ~5whp over the stock log style manifold (much like ours). Same goes for the LT1/LS1 F-Body guys. Longtube headers make big power gains on the LT1/LS1 and when they say longtube, they are VERY long in comparison to the stock manifolds. The primaries on the LS1/LT1 longtubes are about 26-28" long. The primaries on the Maxima headers appear to be about 12-14" long.

 

Or milleniums. . . .

It's almost like the MEVI, it took a long time to compare USIM dynos with MEVI dynos, i seemd like the thing to do was dyno with it open and closed.

As far as design, what would 3-2-1 headers do for us, comapred to the 3-1 design currently out there?

 

No, go back and read the last sentence of the first post. Green line and red line were different cars. The base blue line and the and the Greeen header line are the same cars.

 

Hey Caesar, have you noticed any increase in engine bay temperature since installing the headers?

 

I think he got confused because here is the 2nd and 3rd sentence of the first post:

"The stock run was not my own, but borrowed from another member as i had no access to the runfiles for my own baseline. However I used it just to illustrate the differences in the power curves."

I asked him why he didn't use his stock run (which he has posted on his website) and he said the data wasn't in the runviewer format. His stock dyno was 205whp/213wtq.

 

Then again, their intake manifolds are tuned for mid-range power so the headers wouldn't help THAT much on the top-end anyway. The intake manifold is the bottleneck like he mentioned in his thread.

I personally think a USIM+Cattman header dyno vs. USIM+aftermarket y-pipe dyno will be pretty useless. Like the JWT cams, the headers need to be used in conjunction with the MEVI (or DE-K VI) to exploit their top-end characteristics if any. With the USIM we'll never really know.

MEVI+Cattman header dyno vs. MEVI+aftermarket y-pipe dyno is the way to go IMO.

 

+ JWT ECU

 

bump......it to the top.