Kicking the Cat

[IanA2]

I'm thinking of dumping the Cat on my 92 500SL (beats the law by 3 months). Is this sensible? I've been told that it will improve fuel addiction by about 10% (not looking for the extra BHP you understand!). Is this a sensible move? Are there issues re engine management system etc? It's a good car and I don't want to drive it into an early grave, so if it's a silly idea, I'll leave it. It is tempting though. I'm looking at the SS Powerflow system. All thoughts gratefully received.

Thanks

Ian

 

[stwat]

It should be ok as long as you leave the lambda probe in place. That way the car can still adjust its mixture.

Stu

 

[Copiertech]

all the vehicles i`ve seen it done on run better with no bad effects. you may notice a slight rasp which IMO sounds brilliant.
even if your car is newer than 92 you can still decat it if your running lpg, you just adjust the idle mixture using the software so it passes the emissions test. contrary to popular belief you dont actually need a cat to pass the mot, your emissions just need to pass the yest, which most cars cant do without a cat. with a vauxhall 20XE on throttlebodies with a mappable ecu you can pass the cat test without a cat if its mapped right.

 

[IanA2]

all the vehicles i`ve seen it done on run better with no bad effects. you may notice a slight rasp which IMO sounds brilliant.
even if your car is newer than 92 you can still decat it if your running lpg, you just adjust the idle mixture using the software so it passes the emissions test. contrary to popular belief you dont actually need a cat to pass the mot, your emissions just need to pass the yest, which most cars cant do without a cat. with a vauxhall 20XE on throttlebodies with a mappable ecu you can pass the cat test without a cat if its mapped right.

Thanks for that, yes I've heard the resulting sound is awesome....especially with the top off !!

 

[Shude]

thread moved to engine section

 

[IanA2]

SS Manifold or not....

I'm about to get a stainless steel powerflow system. My mate says I should spend £500 more and get a ss manifold too. I tried asking MB for advice without a great deal of success. I am interested in performance and economy. I understand that by removing the cat I will increase the power a bit and also improve fuel consumption, is a ss manifold a good idea? Also anybody got any ideas about what kind of nice shiny pipes I should have a look at?

Thanks

 

[splang]

So, what does Ray think about this?!!!

 

[Ian B Walker]

So, what does Ray think about this?!!!

classic

 

[IanA2]

So, what does Ray think about this?!!!

Translation appreciated

 

[Ian B Walker]

Translation appreciated

Ray's name here is kickthekat does that answer the question.

 

[IanA2]

Ray's name here is kickthekat does that answer the question.

Many thanks....

 

[grober]

St/st stress fractures

Heard some stories about stress factures in fabricated st/st exhaust systems. Repaired without a problem but owners had to go back to the installer to get them fixed. Dont know if this applied to manifolds or not there are also anecdotal reports of "ringing" exhausts a sound which some people dont like.

 

[IanA2]

Spoken to Ian of Hayward & Scott (link posted by Portzy)

www.haywardandscott.com

He answered all my questions with good impartial advice, result being that I will get a better system than I originally envisaged (without the unneccessary expense of a ss manifold) but with two lovely twin shiny end bits!! With the ss exhaust this will cost less than an inferior single sytem with manifold! That's is what I call a result. They just got themselves a customer!

Thanks Portzy

 

[Shude]

He answered all my questions with good impartial advice, result being that I will get a better system than I originally envisaged (without the unneccessary expense of a ss manifold) but with two lovely twin shiny end bits!! With the ss exhaust this will cost less than an inferior single sytem with manifold! That's is what I call a result. They just got themselves a customer!

I would be tempted to use oem exhaust tips, if nothing else it will make the car look "original" . You could probably have some tips made up to look like the original style ones or I could get you some part numbers for oem accessory tips.

 

[IanA2]

I would be tempted to use oem exhaust tips, if nothing else it will make the car look "original" . You could probably have some tips made up to look like the original style ones or I could get you some part numbers for oem accessory tips.

Would there be any advantage/disadvantage in using oem tips (other than originality) if so then part numbers greatly appreciated.

Thanks

 

[Shude]

Would there be any advantage/disadvantage in using oem tips (other than originality) if so then part numbers greatly appreciated.

Absolutely no benefit other than aesthetic, and possibly ease of resale.

The only tips I could get you part numbers for would be modern oval tips as optionally fitted to the SL/CLK/SLK etc, with or without AMG on them. They are in some cases stupidly expensive though .

Even though your car is an older SL the shape didn't change much and the oval tailpipes became popular in the late 90s, I could dig up part numbers for those if you want.

 

[Alps]

I used hayward and Scott to re-do the front pipe which houses the CATS when they needed replacing, they did an excellent job, and I would def use them again! I chose not to de-cat.

 

[IanA2]

Absolutely no benefit other than aesthetic, and possibly ease of resale.

The only tips I could get you part numbers for would be modern oval tips as optionally fitted to the SL/CLK/SLK etc, with or without AMG on them. They are in some cases stupidly expensive though .

Even though your car is an older SL the shape didn't change much and the oval tailpipes became popular in the late 90s, I could dig up part numbers for those if you want.

Call me square, but I think I'd like the nice square ones! Many thanks for the offer on part numbers though.

 

[BTB 500]

I will also be giving H&S a try. I would like to replace my rear box with something that looks discrete and standard, but is a little bit louder

Just for fun I asked my local stealer to check whether there was a genuine MB / AMG part to do the job, and they thought not. Only option was approx. £1500 and intended for left hand drive vehicles (?), so they couldn't confirm it would fit without modification. So if you have a RHD SL60 AMG and the rear box goes presumably you're out of luck?!

Does anybody know whether a modified exhaust is likely to cause a big jump in insurance premium?

 

[Shude]

Just for fun I asked my local stealer to check whether there was a genuine MB / AMG part to do the job, and they thought not. Only option was approx. £1500 and intended for left hand drive vehicles (?), so they couldn't confirm it would fit without modification. So if you have a RHD SL60 AMG and the rear box goes presumably you're out of luck?!

If you have an SL60 and the exhaust box goes then you get a new SL60 exhaust box.

Try to remember that most stealership employees have no creativity or enthusiasm at all and therefore will only suggest either the stock item or an accessory item that will definitely fit the VIN supplied. Most of their work is standard servicing or warranty parts which must be 100% factory spec.

You could easily have the C43/CLK55 AMG box or something fitted to your car and that would be about £550 from the parts counter. Would need a few minor mods though probably - not really the kind of work stealerships are interested in.