Congrats to our New President Anguss!!
Remember to like us on Facebook!! - https://www.facebook.com/skylinesdownunder

Author Topic: Catalytic Converters - to remove or not to remove  (Read 1564 times)

ph1

  • Guest
Catalytic Converters - to remove or not to remove
« on: June 10, 2001, 03:30:05 AM »
Dave Kemps
Registered User
(6/6/01 1:11:47 pm)
Reply  Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 hi guys just wondering if i should remove my catalytic converter. I've got a R32 GTS. The exhaust is around 3 1/2 - 4 inch from the cat back and got a straight through HKS muffler so i reckon that its causing heaps of restrictions.

my only reason for not doing it is because i heard somewhere that all kinds of oily muck can come out the back if u remove it and it ends up on the back of ur car! is this true??

does it make ur car more prone to backfiring? hope so cause mine does it occasionally already!


 
BABY R
Registered User
(6/6/01 2:32:49 pm)
Reply
  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 Yes, all the muck will get fired through and will stick onto the rear bumper of your car and its hard to clean off too! Yes you will get more backfire and poping sounds too.

3 1/2~4" exhaust...hmm isn't a bit too big for a non turbo?

Boost it up and rev to the red!
BABY R
 
Dave Kemps
Registered User
(6/6/01 2:36:15 pm)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 yeah i know, it huge! already had it when i bought the car, well is there some way of removing the converter but not having the crap on the back of the car??

Edited by: Dave Kemps at: 6/6/01 2:37:59 pm
 
BABY R
Registered User
(6/6/01 2:40:17 pm)
Reply
  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 it really depends on the design of the exhaust system, on my GTR i got a trust power extremeII exhaust which featured a 4" pipe, a racing cat and no resonators in between, thats why the rear ends of my car is always dirty with carbon and its really really hard to clean off.

but my old exhaust which is a trust item also is a 3" system, got a racing cat and got one resonator before the muffler, which helped to eliminates plenty of carbon deposits on the rear ends.
Boost it up and rev to the red!
BABY R
 
nustad
Registered User
(6/6/01 3:33:35 pm)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 If you did take out the cat then I would consider putting a resonator back in - just to maintain some backpressure.

I would be guessing that size exhaust would be hurting your torque curve......talk to Al's mufflers.

If your car is properly tuned then it shouldn't shoot crap out the back. I have a GTS25 which is not properly tuned but it still leaves the rear bumper clean.

Cheers

GM
 
Dave Kemps
Registered User
(6/6/01 4:11:57 pm)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 i put a resonator in the end of the exhaust normally, this keeps the noise down. i sometimes take it out and power and torque improve quite a lot. this is why i reckon i should take out the cat. my car is well tuned so hopefully it shouldnt spit crap out the back. prob should ask a exhaust specialist tho, they might know about my exhaust, if its too big or not and if i should take the cat out.
 
WDRacing
Registered User
(6/6/01 4:23:31 pm)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 Well it's not like the 4 bolts are hard to remove and reinstall. I'd take it out and if you don't like it put it back in. I was also wondering what an NA was doing with such a big exhaust. I figure it would kill any low end torque.

WDR
 
Dave Kemps
Registered User
(6/6/01 10:50:59 pm)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 well, the exhaust is standard from the cat forward so many that restriction is why the low down torque is ok. i dunno really tho, it seems the car goes fine and has heaps of torque!
 
forsteen
Registered User
(6/6/01 11:01:21 pm)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 Hey WDRacing, how hard is it to get past JCI w/o the cat. The guy I bought the car from said that there is a plate he puts in order to basically hide where the cat would be. I also heard that they lift you car to check and also put a emission probe down your tail pipe to check emissions. Is any of this true. Gonna need it. My JCI due this month.

Thanks
Forsteen

Hey!! Where are my pants!!??
 
WDRacing
Registered User
(6/7/01 1:59:00 am)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 We don't JCI our cars. Get with me in person on this topic or email me. It'll cost you a little money but you can leave all the mods on.

WDR
 
forsteen
Registered User
(6/7/01 2:08:26 am)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 Ok, I'm listening. My e-mail is Forsteen@Hotmail.com

Or we can meet this weekend. Whatever is easier.

Gettin giddy.
Forsteen

Hey!! Where are my pants!!??
 
WDRacing
Registered User
(6/7/01 5:51:19 pm)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 Lets hook up this weekend. I'm pulling the head off my spare eng. Then I'm going to try my first head port by myself. Should be interesting....

WDR
 
forsteen
Registered User
(6/7/01 11:36:16 pm)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 Yeah, I'm not doing to much this weekend anyway. Gotta save up for the INSPECTION. We can set a up a time and place or I can meet you where ever. I ordered a Master Cylinder kit so I gotta do that anyway.
Forsteen

Hey!! Where are my pants!!??
 
xvenomousx
Registered User
(6/8/01 1:47:42 am)
Reply  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 remove your catalytic converter, chances are its not doing its job. alone they can knock 5-10% off your bhp, and your economy. you also want to ditch the 3" for a a nice 2.25" system since you have a no turbo DE. you should gain 8-10kw from a good exhaust on GTS.

I driven a RB30 holden with a 2.5" and no cat since i first got my licence and never had that problem.
following a diesel truck on the motorway for 5 minutes is the real way to put carbon deposites on your car.

Cat's don't work after about 60,000km anyway.



Edited by: xvenomousx at: 6/8/01 1:57:14 am
 
Razor GTSt
Registered User
(6/8/01 5:09:39 am)
Reply
  Re: Catalytic Converters - to remove or not to remove
--------------------------------------------------------------------------------
 This is an interesting subject. One that I can already see can go either way. Ok so I will put my nose into this one as I have documentation.
When I purchased my 91 GTSt it had @58,000kms on it. I had done a dyno run in stock trim. The produced 105.3 kw @ the wheels on a local dyno.
I put a K&N panel filter in the factory airbox. Back I went and it went up to a staggering 107.4!

This topic we are on here now has come up so many times in the past. I had my cat removed an a piece of straight pipe put in place. Back I went. Well guess what. My power went backwards!!!!!! 105.9kw

The cat was removed at @66,000 kms. It did not look blocked or bad either. Remember now I have the turbo version of yours. Any restrictions will hurt me even more as I have not only the normal exhaust streaming through it plus when I come on boost the waste gate also dumps into the same piping. This would even add more volumne of air being forced down the exhaust pipe.

When I had my GTS I put on a 2 1/2 inch custom system. It was too big for my 2 litre. I should have went to a 2- 2 1/4 inch system.

Everything I have done as far as performance mods have been documented with a dyno run on the same dyno from the word get go. This is something I wish others had done but hey at least I am doing it so others can see real time results for each thing done. No guessing. If you want to see more check out my site. razorgtst.esmartweb.com



Vincent Sala
SDU Sponsor Liaison
Skylines Downunder Car Club Inc.