[Guest]

Well, the deed is done (for those that wanted to know), despite Co-ordsports best efforts.
I'd got a pipe from them as they did a stainless one that supposedly fitted my car for the same price as having one made.
Despite me informing them of the car model (Evo 1) and the full chassis number, they supplied me with the wrong parts.
I queried it as it didn't look right when I got it, they took the chassis number, part number etc and re-assured me it was correct.
Then on the day I was about to swap it they rang me up and said actually it was the wrong part number, and in fact they have no de-cat pipes that fit the Evo 1.
And they still have not refunded me on the bloody postage.

So I got an exhaust place to make one -Tony Law competion exhausts in Leeds - they also do full road legal Group N systems for evos, or can make them up from scratch, and fit it.

Results: Not the massive horsepower gains claimed by some,more like the 10bhp or so I thought I would gain...However as my car seems to have the only surviving standard system in the world

its hampered by the twists and bends in that.
The extra grunt is more noticable when I have family and associated crap in the car (pram etc).
The speedo needle definatly spins around the clock faster and the turbo spools up sooner and faster.
Good start for more mods... I'm thinking the small silencer to the rear of the system is ripe for junking, followed by a straight through backbox.

TonyC

 

[Guest]

The Coordsport parts cockup story sounds rather familiar.

Rearrange the following phrase:

elbow know they from arse don't their their

Hmmmm

 

[Guest]

Did you just remove the cat or did you go for a full down pipe? What size?

 

[Guest]

Just the cat ... I've about 500 other things to pay for at the moment....

Also noticed today that the top end doesn't peak out as much.
TonyC

 

[Guest]

You will see bigger gains if you change the whole down pipe.

 

[Guest]

I'll get there, I'll get there.......

TonyC

 

[Guest]

A bit of a wierd one this.....

I had a cat replacement pipe on my Evo4 plus a 5Zigen exhaust and I just stuck the cat back on for my MOT. The car seems quieter than before and it seems to pull better at low rpm. The top end hasn't changed that much but I have noticed that the peak boost amount has reduced when I looked at the screen of my boost controller. I have upped the boost ratio and removed some more silencer wadding from my exhaust tail pipe and its running better than ever before !!!.

I'm now not convinced that removing the cat gives a performance increase of any worth. The car seems more comfortable with the cat in place ???

Why is this ?

Jonathan

 

[Guest]

What do you mean by the boost ratio?

 

[Guest]

I too removed the cat from my ARC exhausted 4 and seem to have introduced a vibration or reasonance above 4000 rpm - anyone else come accross this problem ? Might put the cat back to see if it cures the problem. I have also done the grommit removal so maybe that has done something

 

[Guest]

Wreckleford,

I have a Blitz dual SBC which has the ability to alter the boost gain and ratio.

These functions allow the boost to be regulated so that you can have more lag but a kick in the pants when the turbo comes in, or less lag where the boost rises slower but keeps rising.

My car is much nicer to drive with the CAT in place. It seems more responsive at the bottom end and smoother when driven. The idle is also REALLY steady now. I would get the occasional misfire at idle before the CAT was put back on the car.

It seems as tho' the removal of the cat creates a sort of bottle neck in the system if a standard exhaust is still in place.

I spoke to a friend who has a complete exhaust system from turbo back and no cat, he said that the reduced back pressure will cause the ECU to run the car slightly rich. The back pressure seems to keep things balanced. He uses the APEX Super AFC to weaken his mixture. The only problem is that unless an exhaust gas temp guage is used, there is a risk that the engine will run lean and hot. This may result in engine damage due to detonation..

Dave 4.. Try replacing the cat and let us know whether it is smoother again. Do you really think that your car is faster without a CAT ? or just noisier ??

Jonathan

 

[Guest]

Well my personal experience with my Evo 1 is as follows:

Bought it with a 3 cat back exhaust.

Replaced the circa 2 dia. down pipe and the cat with a 2.5 mandrell bent pipe (catless). The boost as controlled by the ECU went up by 1 psi and the spoolup was improved. I did not notice any adverse change in idle quality, smoothness, driveability etc.

By the way, these cars run very rich from the factory, so I think it would be hard to say if the removal of the cat caused the car to run any richer.