Here is the deal guys. I have done this on a 99 mercury cougar (which I understand is a different car). Since header options for our cars seem to cost an insane amount of money I am committed to coming up with an alternative method for getting more power out of the exhaust manifolds. I will pay for the dyno before and after and any other costs I run into along the way. All I am asking for is a spare set of stock exhaust manifolds (probably from somebody who has replaced them with headers) so my car wont be down for the duration of the testing.

My current plan:

1)Dyno test car to get baseline numbers
2)Remove all cat material from both manifolds
3)rig O2 sensor dummy wires to prevent a CEL
4)Gasket match openings of manifolds to match heads and y-pipe
5)Dyno test car again

If there is no interest in this then I guess I will just keep it to myself, but if I am not the only one out there that is wondering how to squeeze out and extra 5-10HP out of these engines then please step up and help the cause...

Thanks,

Mark Lupiani

 

Hi Mark,
If you are going to gut the cats, then you might want to think about sending the manifolds to Extrude Hone to have their process done. I've heard it produces fantastic results with exhaust manifolds! Not only does it open up the cross section of the runner it smoothes and polishes the runners which lets the hot exhaust gases flow easier. This process has made some decient flow improvements on aluminum intake manifolds, and most of there automotive advertising is done using the mustang 5.0L intake.
Here's a link to the price list for Extrude Hone:

http://www.extrudehone.com/price_list2.pdf

It looks like it'll run about $575 to do V6 exhaust manifolds.

Tom

 

org member Juice has gutted his stock stuff and I don't think he showed any gains from that...he ended up going stillen headers after all

 

Might as well buy the headers for that price.

 

how do you plan to do this? do you mean relocate the O2 sensors behind the cat or a fake signal? If you have a way of making a fake signal i would like to know!

ps -- i dont think gutting is really worth it. Didnt sr20den and juice do this and get basically nothing?

 

i was considering the same thing this past summer... it sounds like a good project, if you can do the work yourself, saves some $$ too. Hope ya find a set

 

Didn't Don in Texas do this to his 4th gen?

 

I have two gutted cats for u...check your PM

 

2KGLE - You can fake a signal. Search around http://www.fastcougar.com/forums/ for a how-to. I would like to hear from some more people who have possibly done this mod and have feedback. Headers for the 02 maxima are extremely overpriced. The stillen headers are a waste of money (for that price you can get a 100 shot system of nitrous). Even the Hotshot headers are way overpriced. When they come down to about $500 or so I will buy them. Maybe a group buy will help but they want WAY too much money. The price for the technosquare ECU is way overpriced too. You look at the price of a computer chip upgrade for any other car and it is around $200-300 (and 99% of chips do everything the technosquare does).

If anybody else has info on header alternatives please speak up. That extrude honed idea is a good one.

 

I read something on a maxima site where this one guy ported and polished his exhaust manifolds and only got like 1/2 horsepower and a tenth more torque to the wheels. It doesn't seem worth it to me.

 

Search e-bay someone is selling some for like 15 dollars. You will not get any HP from it though.