emax02

iTrader: (1)

I just came up with this idea out of shere bordem . 2002 owners probably can do this and then get a fed spec aftermarket Y-Pipe. I just need to touch base on this whole idea and I would appreciate input from all of you.

My beta plan is to first find out if the header gaskets are the same part # from 2000 to 2002. Can anyone help me out with this info?

Seeing that the engine is externaly identical(to my knowledge) in shape to the 3.0 the fed spec headers should bolt on very nicely.

Now from there it is a little hazy with all the electrical gremlins, I have heard a few different theorys on this topic. Some people say that the o2 sensors work fine when they are mounted in the fed spec pipe but other's insist that the o2 sensors need to be mounted south of the main cat. Whats the truth behind this? Do I have to have my B-Pipe drilled and my o2 sensors mounted back there?

If all this works out which it should we would be able to put any aftermarket Fed spec Y-Pipe on and we should see some awesome gains!


Please help me out and let me know what you think of this idea? Total projected price is under $500 doing my own labor. Gains should hit about 20 FWHP.

sleepermax

iTrader: (5)

I don't know about the '02's but I've done this on both my auto and 5-speed 2k1's. Initially I though it was worth it but now I'm convinced it's a waste of time. I did this after installing a Cali spec Stillen y-pipe with the fed-extension peiece. The "gains" are very, very minimal, if any, and there is a loss of low end torque. The main reason I did this was because I was concerned about any negative long term effects of removing only the rear pre-cat and leaving the front pre-cat in place. But the Fed-spec 2K's come stock with only a pre-cat after the front manifold. So aparently this doesn't have any negative effects, if Nissan does this stock.

I've since put the front pre-cat back on and returned the O2 sensors back behind it (you do have to relocate them behind the main cat if you remove both pre-cats, otherwise you'll get a CEL).

Having played around with many different exhaust set-ups on both Max's I can tell you I don't think a y-pipe will help on 2K2's. Nissan has redesigned the stock y-pipe and pre-cats. The rear pre-cat definitely looks to be a much better flowing design than 00's and 01's and the stock y-pipe is of equal lenghts. The front pre-cat was already a very free flowing design on 2K's, 2K1's and now 2K2's. This means that both cylinder banks are experiencing similar back-pressure, with minimal restriction from the pre-cats, thus maximizing power and torque. It really is an EXCELLENT design now.

I'd say about the only thing you could do for gains exhaust-wise would be to remove the crimp on the b-pipe behind the resonator. You will feel slight gains but not much to get excited about.

I'd spend money on other stuff first, like a pulley, intake, synthetic engine and tranny oil, and even an engine oil cooler (helps maintain spark advance longer), before doing anything with the exhaust.

emax02

iTrader: (1)

Thank you for the very informative reply. I can't help but think that removing the 2 precats will show very good gains though. As you probably know there are no Y-Pipes available for the 2002 so the comparison would be 2 pre-cats VS none. I still think I may try this. If I put my o2 sensors into a Stillen Y-Pipe what exactly would the effects be? Would the only problem be that the MIL light will go on or will my car run funny too? Thanks for the help

y2kse

iTrader: (1)

There's your problem in a nutshell, emax95. Stop thinking! Sleepermax is right.

emax02

iTrader: (1)

If every one had that logic were would we be today? Ahh heck I'm going to go put some 265/40 17's on my stock rims

BioMaxDDS

iTrader: (1)

i'm stupid
what is cali & fed spec?
what's the difference?

y2kse

iTrader: (1)

Yeah, yeah. That'll work!

nm

emax,
from what I remember from the writeups about this that were done a while back, you have O2 sensors, 2 in each bank (see manual for which is which), 1 is for A/F controll and the other one is an emissions check , all it does is look for an emissions drop and that is the way it checks if the precat is working. The A/F sensors have to stay in their particular bank, but since you don't have the precats anymore you need to fool the emissions check sensors into thinking the pre-cats are still there, so you move them behind the main cat, now they see an emissions drop and think everything is ok, and no CE light.

hope this helps,

nm

emax02

iTrader: (1)

The only thing you need to know is if we made are car's "fed spec" we could put a Y-Pipe on


nm, thanks for the reply. The thing I am wondering about is what will happen to my car in regards to running well(in terms of HP out put) if I put the o2 sensors back into the Y-Pipe, will the car still run well? I am not really concerned with emmisions. I recall someone saying that with o2's not relocated the car would go into limp mode, is that true?


Thanks for the feedback, please keep it comming

Can anyone check the gasket part #'s for me?

emax02

iTrader: (1)

I calculated the final cost of this. I can get 2 oem fed spec headers for $70, a stillen Y-Pipe for $340 and gaskets for about $40. All together it will cost me $450. The installation will however be quite diffucult, luckly the bolts should come loose fairly easlaly since the car is so new.

nm

That's correct, the car might go into limp mode if you do not relocate the emissions O2 sensors (2 of them, one from each bank), you put the other 2 A/F O2 sensors in to the Y-pipe because they have to stay where they are now, close to the manifold to get proper A/F readings, the emissions sensors go behnd the main cat to fool the ECU into thinking youre still cali spec (you have to make 2 holes in the B-pipe and weld in the sensor receptacles) then the car should run well because the ECU doesn't know that anything's different and you get the full benefit of a cat free and free flowing y-pipe.

There use to be a link to a website with all of this info for a CAL2K1 to FED2K in the FAQ but the link is not there anymore, the bookmark I havd is a dead link now. Also, if you do decide to do this, remember to get the appropriate manifold heat shields too.

emax02

iTrader: (1)

I understand you now, thank you very much for the help. I should be able to drill a threaded whole however and then just screw my sensors in right? Welding would be a pian.

sleepermax

iTrader: (5)

Well emax, if you really are set on doing this..here's what I recommend: leave the front precat and front manifold in place. Just replace the rear precat and manifold. This will accomplish two things:

ONE - you won't have to relocate the O2 sensors behind the main cat. This is a hasle, although even if you just left them hanging free in the engine bay, for example, the only thing that will hapen is that you'll get a CEL. Drivability or performance won't be affected at all. I've tried this to see what would happen.

TWO - leaving the front pre-cat/manifold in place will enable you to use a cali spec Y-pipe so you'll have a very easy/convinient place to put both rear O2 sensors. Also, and most importantly, I have a very strong suspicion that this set-up (leaving the front pre-cat/manifold in place) results in more equal back pressure for both cylinder banks. You have to remember that although you'll remove the rear pre-cat, the distance that exhaust gas travels from the rear manifold to the main cat is significantly reduced when using an aftermarket Y. To put it simply the main cat is now much closer to the rear manifold - creating a backpressure pretty similar to that of the rear pre-cat. So I'm very certain both cylinder banks now "see" more equal backpressure. This in conjunction with using the y-pipe (which is larger in diameter and has smoother bends than the stock y) will likely result in pretty decent gains (I doubt 20 FWHP though). Keep in mind I'm not just speculating here - I've actually gone throught the trouble of trying this and a bunch of other set-ups on my 2K1's. I'm very certain this set-up will result in better performance in conjunction with our "green friendly" cali spec ECU's - it's a different story with Fed-spec 2K ECU's though.

If you feel comfortable with removing the rear manifold then I say go for it. I'm pretty sure you'll feel results but I'm not so sure it'll be worth the trouble. It all depends on how easily you can replace the rear manifold - this is key.

emax02

iTrader: (1)

Thanks again for the help! I don't know if a Cali spec Y-Pipe will even fit onto the front bank of a 2002 max though? The 2002's may be of a completly different design. I suppose when the time comes and I do this I will probably have a stillen Y-Pipe which works for both Cali and Fed spec(2 piece pipe).

I like your plan though, replacing just one header would be much easier and cheaper to do, I just hope it will fit.

psu max

was it this site?
http://www.desertpearlmax.homestead....aModsPage.html
and
http://www.desertpearlmax2.homestead.com/Fed_YPipe.html
?

WILLSE

hey man keep me informed! u got my interests up i would like to do this conversion as well! i will talk to my performance shop and see what they have to say and if it can be done and if the headers will even fit from a 2k max to a 2k2! good idea!

will

nm

yes, those are the sites, I guess I had very old bookmarks.

nm

I think you have to weld in the proper sensor receptacles because if you just drill the threaded hole it would not have the full thread depth of the proper receptacles and also it would not be uniform since the pipe is round which I think will give you medium/long term reliability problems. You can take a look at the photos on the website that psu max listed, that is the one I was talking about.

y2kse

iTrader: (1)

I remember Desert Pearl's CA/NLEV to Fed Spec conversion very well. I had just forgotten his handle.

I also remember the outcome of his conversion and his ultimate recommendation. What he said, in a nutshell, is that the conversion wasn't worth the time, effort, or money he expended.

But you know, some people simply have to learn the hard way.

emax02

iTrader: (1)

No, some people just want a Y-pipe to fit onto a 2002..

sleepermax

iTrader: (5)

Yeah - I definitely have to agree it's not at all worth the trouble on 2K1's. However for 2K2's it may be a different story since the main objective of this would be to fit an aftermarket y-pipe. Not necessarily to "convert" the car to Fed-spec. To put it much more accurately you'd be converting a 2K2 to the exact same set-up as a cali spec 2K1 with an aftermarket y-pipe. I can almost guarantee (short of trying it myself since unfortunately I don't have a 2K2!) this will reslut in some gains but I'm thinking more like 10 FWHP or so, not 20! Repacing the rear manifold may be more trouble than it's worth.
A lot of times it's good to try stuff even though the end result MAY moot because you learn a whole lot more along the way.....

y2kse

iTrader: (1)

OK. I get the point. I'll be interested to see how this works out.

emax02

iTrader: (1)

I'm going to try to get this project cooking next Tuesday. I have to shop around a little bit and buy a Stillen Y-Pipe and I am also going to get the part #'s checked out on Tuesday. I will keep you you updated! Dynoes will follow shortly after this project is completed If everything goes smooth I should have this all done in 2-3 weeks.


Thanks again for all the help guys, I really appreciate it Who ever's web site that is, thanks too!

Weasel

iTrader: (2)

Man, if Stillen really is making headers you're going to be kicking yourself for a long time after this. Hold out til you know for sure if they are or not.

emax02

iTrader: (1)

Bah, this is a few hundred cheaper and I don't have to wait . I don't know how stillen is planing on dealing with the o2 sensor gremlins, I bet well never even see headers, I could be wrong though.

sympatico

Monster Inc is being smacked!!!