Test Pipes.

[jaffaz32]

What year test pipes do i need?

My car is a 1997.

However i will be ordering from the US which their years differ from ours which i found out.

Would my 97 have sensors in the cats?

When you go test pipes surely i need to refit these sensors or the ecu will get false readings.

What about the Taitec test pipes?

[Sudesh]

If your in the UK then more than likely you will fail MOT with test pipes, unless your prepared to swap them out every year.

Your cars a 3.2? so you need the 3.2 pipes

Yes you have 02 sensors, your car is OBD2 II so you have 4 O2 sensors. The ECU will throw you a code, I think 0420/0430 code "catalyst effeciency out of range" and some reported the car went into limp mode and trigger CEL light; unless you can get some type of 02 simulator, or I have seen people with test pipes with holes for the OEM sensors to go back in, to pick up the down stream and up stream flow.

Not only that but you will see allot more black soot around your bumper too and exhaust typically smell more rich.

Personally I would look at high flow cats




What year test pipes do i need?

My car is a 1997.

However i will be ordering from the US which their years differ from ours which i found out.

Would my 97 have sensors in the cats?

When you go test pipes surely i need to refit these sensors or the ecu will get false readings.

What about the Taitec test pipes?

[NSXGB]

The Taitec test pipes have the threaded insert for the o2 sensor.

Interesting to read Kaz's take on the removal of Cats - no real power gains & sometimes a small loss but slightly more free revving and slight weight saving.

Worth bearing in mind before you remove them.
Also, as mentioned, unless you have an understanding MoT inspector you'll have to refit them briefly every year.

[Sudesh]

Yeah totally agree. I dont think I would change out my cats for the reasons Kaz mentioned and also I recently upgraded my exhaust and I like how it sounds and rear end stays clean. I looked at and worked on NSX's that had test pipes and they were extremely loud.

Not sure how the High Flow cats sound with aftermarket exhaust?

[NSXGB]

Agree with the increase in volume but not noticed excess soot on the rear of my car.

[NSX 2000]

Not sure how the High Flow cats sound with aftermarket exhaust?

A tiny bit louder, but still not enough to fail a track day noise limit test. When Noel drove off this morning it did sound very nice but then again I'm biased :D

[jaffaz32]

My car is a 3.0 5 speed.

I think it was one of the late NA1 models before they become the 3.2's

I thought about high flow cats.

That is all so confusing.

There are Prospeed and SOS with Random Technology cats.

Prospeed list 400CFM

SOS list 300CFM

however random technology list 617CFM i think.

But this is the confusing thing, SOS use random technology cats so sure it should be the same as random technology list?

I personally like loud exhausts, well lets define that a lil. French cars/small engines big exhausts = Meh! not good. But Sound of a *** car running a nice loud exhaust sounds pretty awesome.

I was going to go decat and swap over for mot's. It's only once a year.

I think i was mainly looking at it from a performance and sound point of view. Ok you might save some weight, i know every little help but the amount saved is hardly any.

So that leaves performance and sound.

I'm still bit confused why SOS and Random Technologys list different flow ratings although SOS use random technology cats.

SOS http://www.scienceofspeed.com/products/exhaust_airflow_products/NSX/Random_Technology/high-flow_cat_converters/

Random technology http://www.randomtechnology.com/index.html

prospeed http://www.nsxprime.com/forums/showthread.php?t=133876


Can someone please clarify.

What is best for performance?

What is best for sound?

Can you use factory O2 sensors with any of these test pipes or high flow cats?

Mentioned, was stated the Taitec have the plugs for o2 sensors, what about the other two.

Anyone got any idea why sos and rt list different CFM? As Prospeed flow more than sos but rt flow more than prospeed. according to figures quoted on the web.

[Senninha]

Without back to back testing on the same car / same day then which performs best will end up being someones personal view. You should also bear in mind that if someone has just invested some money in either t/pipes of high flow Cats, they are unlikely to say that they haven't improved performance.

On my NSX I have the following set-up

- H&S cat back exhaust
- OEM 3.2 headers
- Prospeed high flow Cats
- ProCar CF intake and scoop

This combination allows smoother revving and delivers power a few hundred RPM earlier in the rev range as shown on the TDI rolloing road.

Power was up from stock to 301 and I've not tested again since installing the Cats so at this time (and as per my earlier comment) I'd like to think they have added more than just a little soot to the rear bumper :).

Overall sound of my NSX is more subtle than other after market systems, most of which are far too loud for my liking. The H&S systems offers a deeper more rounded sound compared to the higher pitch produced by most of the A/M systems.

HTH

Paul

[NoelWatson]

Can you use factory O2 sensors with any of these test pipes or high flow cats?



You should be OK, but the 02+ cars are having issues with CEL being triggered and power being curtailed at the top end (although this may be due to dirty air filter)

[jaffaz32]

I just realised something!!

I got under my car today to see what is going on there.

I was under the impression the O2 sensors go into the cat pipes. Which they don't they go into the manifolds.

When you order manifolds do you get the pipe also which goes between the cats and manifolds? I have cantrell ones on order

[NSXGB]

I just realised something!!

I got under my car today to see what is going on there.

I was under the impression the O2 sensors go into the cat pipes. Which they don't they go into the manifolds.

When you order manifolds do you get the pipe also which goes between the cats and manifolds? I have cantrell ones on order

Might be worth a look here:
http://www.scienceofspeed.com/products/exhaust_airflow_products/NSX/ScienceofSpeed/exhaust_adaptors/

[AR]

Should have waited for my system and test pipes. :)

SOS will find it confusing as UK and US vary and even UK and UK vary. Some 1997/1998 cars have the adaptors added to a 1994 OEm muffler from Honda.

[jaffaz32]

after some googling i found this little diagram here on nsxcb

http://www.nsxcb.co.uk/testvb/attachment.php?attachmentid=5559&d=1243433658

From what i saw it looks just like this one underneath.

[AR]

Looks then just like a regular 1990 to 1994 exhaust.

[NoelWatson]

Should have waited for my system and test pipes. :)



How are you planning to stop CEL being triggered?

[jaffaz32]

How are you planning to stop CEL being triggered?

Good question, would be keen if anyone has any ideas?

The easy option is AEM EMS but... before i go down that route there are a few bits i would like to do first.

Any other suggestions?

Another option would be. Say no to test pipes and go for 100Cell cat pipes, but there is no clear answer that 100cell will stop the cel light, the next ones up 200cell are apparently confirmed to stop the cell light but then were getting further and further away from the test pipes.

[AR]

Must be an LEV thing as from 99 down never had a problem.