Catalytic Converter Deletion

[944turboS]

I had split the back of the cat where it tapers back down last Saturday at Donnington, was gutted to have to remove rather than replace the restriction due to financial constraints.

 

[Diver944]

Anorak alert [8|]

Pictures please []

 

[charles.y]

Hi Graeme,

I too want to replace the silencer with a straight thru pipe as you did. I wonder of you noticed any differences with/without cat.

Charles

 

[944turboS]

First impressions are improved exhaust note under acceleration & still comfortable at cruising speeds.
Was another pony liberated? The car certainty feels a little quicker, seems to start to pull a little lower in the rev range. The "Rollers of Truth" will reveal the reality later this month.

On the Dyno the car made 206bhp with no other mods. It was the highest rated car on the day.

 

[zcacogp]

ORIGINAL: 944turboS

On the Dyno the car made 206bhp with no other mods. It was the highest rated car on the day.

Excellent. My S2 made 203.5 the other day, with the centre silencer (in place of a cat on non-cat cars) in place.


Oli.

 

[944turboS]

So I got a real 2.5bhp for £65, or put another way £300 less than a new cat & no power gain. []

 

[zcacogp]

ORIGINAL: 944turboS

So I got a real 2.5bhp for £65, or put another way £300 less than a new cat & no power gain. []

And (more importantly) have a car whose engine is in very good condition.

When I took my S2 to a rolling road (the pork vs. beef one run by Pistonheads), it lined up with a load of new and nearly-new 911's, and a stack of TVR's. The guy running the session asked what BHP figure I was hoping for. I said I would be happy with anything over 190. The expression on his face suggested I was optomistic ... when it showed over 200 on three runs he was impressed that it was doing so well after 120,000 miles.

I'm not sure what is typical from an S2 of this age, but I was pretty pleased. Bravo with your figure.


Oli.

 

[charles.y]

Am I right that the de-cat/mid pipe replacement that ESS offers is a direct cat replacement with a silencer (the pic in their web-site seems to indicate that). As I want to remove the midbox sillencer, therefore a straight thru pipe (like Graeme did) seems more beneficial (less restriction) and cost effective?

Charles

 

[944turboS]

Oli
All the graphs from Weltmeister (The Rollers of Truth) are here
http://www.cannell.co.uk/944%20UK%20League.htm

Charles
You are correct, the details for the outfit that did mine in Walsal are in the original posts.

 

[charles.y]

I wonder if there are places in the SE will do the similar job like MIJ. Walsal is bit far for me.

Charles

 

[charles.y]

Just had the silencer in the front pipe on my S2 cab replaced by a straight thru pipe by the guys in Longlife down in Basingstoke yesterday. It took them more than an hour to do the job and for a merely £50 all in.

My immediately feelings straight after the replacement are ...
- The old rattleing noise on the old silencer is gone and so the annoying noise on the gear lever because of that
- The car seems accelerates better and the gas pedal is lighter, more lively and more responsive
- Its is not that much louder and sounds a bit better

The guy said taking out the silencer may gain 2-3 bhp but the car should feels more lively which I proved that's right after driving the 944 back to work. So £50 very well spent.

 

[Diver944]

Result []

Thanks for the feedback Charles.

 

[944turboS]

That's exactly how I felt after getting the same done to my Cab.

 

[jez_anderson]

"high performance cat replacement can with racing pipe"

Anyone heard of one of these? and what it does?

Longlife exhausts in Leeds have mentioned it following an enquiry I made to them about decating. Cost about £70 as opposed to £30 /£50 for a straight pipe.

 

[charles.y]

Jex,

That wasn't on offer when I had mine done in Longlife Basingstoke. I just went in and asked specifically for the old silencer to be removed. Did they mention what kind of performance gain over the straight thru pipe?

Charles

 

[Fen]

It's going to be a silencer pipe instead of a cat. Less gain than a straight through for more cost and less noise is my guess.

 

[Indi9xx]

Just to confirm something, during the last two years VOSA have declared several models of car after K reg as cat exempt... I am not sure why they have done this, but we have had several 968's over the last year which had faulty catalytic converters which have passed the MOT due to the VOSA database showing these particular cars as cat exempt when their details are entered into the VOSA computer at the MOT station.... A quick call to VOSA has confirmed that these particular cars have been deemed cat, cat test and roadside emissions exempt.

I think they may be phasing in cat exemption for cars after K reg which do not recieve the tax benefits for low emissions, but VOSA will not confirm or debunk this... interesting though.

 

[jez_anderson]

ORIGINAL: charles.y

Jex,

That wasn't on offer when I had mine done in Longlife Basingstoke. I just went in and asked specifically for the old silencer to be removed. Did they mention what kind of performance gain over the straight thru pipe?

Charles

Having seen one now I think it is what Fen says. Its about 12" long and about 6" in diameter, narrowing at either end to fit into the exhaust system. The inside has what looks like rifling inside which I guess is to help the exhaust fumes spin easily through it.