Zack342

iTrader: (89)

I was wondering if anyone had pictures of the Exhaust system of a Fed Spec Maxima. I am trying to gather information on using a Fed Spec Manifold on my 1999 which has california emissions. I was originally planning on getting headers but based on the advice of Dave B. I would like to look into this route since there is no definitive gain in HP from the headers. From what i can tell all that would be needed is a front exhaust manifold and fed spec Y pipe. I would also need to add a new Bung for my 4th 02 which is in the cat on the Manifold currently.
Here are some pictures of the front Manifold on my car with the pre-cat. It has 2 O2 sensors in it. One on the bottom and one on the side.
From top

From Bottom


this is the engine System Diagram showing the diffrences between my calispec 1999 and regular 1999's
can anyone tell me if the regular 1999 exhaust is setup the same as all 95-99 fed spec cars?
Fed Spec

Cali Spec

sterlingmaxima

iTrader: (16)

props to you for looking deeply into this matter good luck to you maybe your on to something who knows.

SR20DEN

iTrader: (7)

If you're asking if this can be done then the answer is yes. You pretty much have the info you need. However I personally would spring for the (Cattman) headers anyway. The Ebay cheapie headers arent going to gain anything at all. They'll just look purdy.

Zack342

iTrader: (89)

well i was going to wait for the hotshot headers since they would be $300 cheaper. then Dave B suggested that i just forget headers all together since they haven't really shown any noticeable performance gains on 4th gen maximas. He sighted that Cesar and I30Tmike have not seen any diffrence in Et or Trap speed. I assumed that if i were to ject convert my 99 Cali Spec exhaust emissions to 99 fed spec emissions i should gain a few Hp since i would remove this precat.i have thought about it. and $825+$install isn't worth the 7-10 hp that the headers my provide. But maybe if i could find someone who is selling a front exhaust manifold and a fed spec ypipe i would be a little better off than i would be with my cali exhaust emissions. My main question was regaurding where i would need to place the extra O2 sensors that i have and fed spec cars don't and also if all the exhaust manifold for all 4th gen maxima's were the same.
Anyone have a pic of a 4th gen with fed emissions and y pipe installed?/

DaEnigma

http://forums.maxima.org/showthread....456#post248456

Though I think this one really sums it up best.

http://www.desertpearlmax2.homestead.com/Fed_YPipe.html

My guess is the same will be true for the 99 cali spec due to being so similar...

goodhead

iTrader: (4)

sorry for OT but...

zack342 did you get my last pm about your pf Tb??? lmk

Zack342

iTrader: (89)

yeah sorry man HarrisH had dibs and he payed me... its sold..


DaEnigma....thank you.... thank you...... thank you.

Zack342

iTrader: (89)

Does anyone know where i can get 02 simulators?

DaEnigma

NP I was looking into the same thing until I read that...

Zack342

iTrader: (89)

you changed your mind?

DaEnigma

Well seeing as it added only minimal HP/TQ (3HP/TQ from ~4k-6k) and the ammount of work related was more than I cared for I decided at this time it was not worth the effort. Also the general concensus was that the front precat being ~3" in diameter did not hinder flow very much and the main power gain (97%+) was due to the elimination of the very restrictive rear precat with an aftermarket YPipe not the removal of the front down pipe/precat. Keep in mind that if you were to go forced induction/nitro then you may want to do the mod though I am no expert on that subject. From what I understand NA did not seem to see much and the peak HP was the same. If you wanted to do a mod that would help although with alot of work... look into doing the 00VI mod...

Dave B

If you look at the graph, there is a decent amount of power gained throughout the curve. That is key. Another thing to consider is the wildly high correction factor of the dyno the day he dynoed the Cali-spec y-pipe. That does make a difference. If he would have dynoed under better conditions and a more accurate CF, he would seen lower numbers with the Cali spec y-pipe. High CFs almost always show more power than is really there. The closer you are to 1.0, the more accurate. 1.08 is way high for a CF.

DaEnigma

I agree and Dave B is a very well known and respected member here and this is the only dyno of this type of mod I know of. I just felt for the ammout of work (Keep in mind I already have a cali spec Y and I did not want to purchase another) it was not worth it. I may think about this later when I do my clutch/flywheel, SS brakelines, STS, and SFC which have been collecting dust in storage...

Zack342

iTrader: (89)

well i think i will give it a shot and dyno to see what it does. my Greddy Sp alread has an O2 sensor bun after the cat which i am not using. so all i need to do is exten one O2 Sensor. I have a calispec Y pipe and i am purchasing the other piece of a stillen Y pipe like he used. The main concern for me is how hard is it removing the front exhaust manifold.What desert pearl did was he moved 2 O2 sensors to after the cat and i will only move one since there is room for the other in my calispec y pipe. All i have to do is find an org member who will let go of his front exhaust manifold cheap. 3hp and 3tq is alot in the mid range. I only gained 3-5hp from the UDP and i paid $100 for that. Also his car was an automatic so i don't know if that makes a diffrence or not but i think this is worth it.DaEnigma thanks again for the link.
Dave B is right no one has proved that headers make more power than a Y pipe with stock manifolds so what is the point of spengin $825+$400 for install? its only going to give 5-10 more whp over just y pipe.From what his data suggest i can get 3whp and 3wtq for about $100 and a couple hours labor. Not a bad deal if you ask me

Zack342

iTrader: (89)

Can anyone in here describe what is involved with removing front exhaust manifold?

Broaner

iTrader: (10)

Its very easy. Just some bolts. I'm not sure if the gasket is reusable. Removing the radiator might be required for clearance but it seems like it should take less than half an hour.

Zack342

iTrader: (89)

anyone who recently installed headers wanna sell me their front manifold and heat sheild

goodhead

iTrader: (4)

im assuming if you want to get to the rear exhaust manifold however, droping the engine/tranny is requried?

Broaner

iTrader: (10)

Dropping/pulling the engine isn't required. SR20 has done many header installs and he doesn't pull the engine.

Desert Pearl

It's good to see my old write up regarding the Cali-Fed conversion is still getting some discussion. I just finished reading this thread and am adding my .02 worth.

Regarding my dyno results, I believe the correction factor to be correct. These dyno's were done at the same shop, but separated by a month or so. The correction factor is an easy way for non-legit shops or tuners to make their modifications look better than they are for marketing reasons, but I had no such motives. No changes were made to "standard" conditions or sensor locations or settings to the best of my knowledge.

The only thing I don't like on the dyno is that the final pull (after the conversion) is that the ramp-up at the start of the pull isn't accurate. The car kept wanting to downshift and the person that did this run eased into the throttle more than on previous runs.

My opinion of the mod hasn't changed since I created the page linked to above. I think the gains are fairly small, in fact they might not even be noticable to the butt-dyno. Sometimes you see things that you want too also, but I tried to remain objective as much as humanly possible. I recall there being a very slight decrease in torque down low (~2-3k), but do recall small gains through the remainder of the powerband. This also seems consistant with the dyno results (except they only show from >3k). I believe that the diameter of the Stillen front-pipe is slightly larger than the effective diameter of the precat, which would explain a slight torque drop down low, but gains in higher rpms. Remember all other things remaining constant... smaller exhaust piping = more exhaust velocity = more torque down low, but less top end.

Anyhow, here are my opinions on your situation...

When researching front-side Federal-spec exhaust manifolds, I found that they are the same on all 4-5th gen Maximas. I bought mine from www.car-parts.com. I just checked their site and there are several places selling the manifold you need for $25-30 plus shipping.

I believe that you will need to relocate both of your downstream O2 sensors to after your main cat if you wish to avoid CELs. On California emission cars, the rear precat is eliminated and the downstream O2 sensor on that side is relocated to after the front-side precat, so both downstream sensors still "see" a precat so the ECU is fooled into thinking everything is normal. If you remove the front precat and relocate only one sensor, the remaining sensor will now see that the precat is missing and should throw a CEL.

I have a write up on the O2 sensor relocation too, which has some useful information which should pertain to your install as well. My only additional comments are that the O2 bung is just an 18mm nut with 1.5mm thread pitch. Also, I had to use crimp-on connectors for the wiring because I couldn't get solder to stick to the wiring. I tried several kinds of solder and flux, but had no luck. Actually this was fine with me anyways because I wasn't even sure this mod would work and wanted it to be easily reversable. As it turns out I never had to undo it until I decided to trade in my car.

So, I wish you the best of luck and if I can be of any more assistance, don't hesitate to ask.

Zack342

iTrader: (89)

Do i need to relocate both of the O2 sensors to after the cat? Since my Y pipe has provision for 1 of the rear O2's fron the rear manifold? If you look at the systems diagram and the pictures that i took you will see what i am talking about.
I have been search for bungs for O2 sensors and i can find 18mmx1.5mm does this sound correct?
I think i will still go through with this . i got the front half of a stillen y pipe for $38 and the manifolds i can find locally on car-part are $50 so i think for less than a $100 2-3hp is good. PLus my car is 5speed so maybe i will feel this more than you or maybe i may get more power cine i have a couple more mods. anyway thanks for the help

Desert Pearl

Yes, the 18mmx1.5mm sizing is correct for an O2 bung.

I am a bit confused from your y-pipe pictures because I can't find one O2 sensor... namely the rear downstream sensor. Did you move it to the open bung after your main cat in your Greddy exhaust??? The blue one and the one closest to the block on the rear side don't move at all. The white one and the mysterious missing one should be installed after the main cat. See the following diagrams:



should be modified to look like so...



By doing this, your ECU will be fooled into thinking that you still have two precats remaining. The only potential problem I see is if you are in a very cold environment where the main cat doesn't heat up quickly enough to satisfy the emissions control.