SH || NC

John, did you go with a straight pipe for now or gutted factory cans?

DHI

John,
How much mileage does your car have?

CT03911

The meter man was in fact present at Lime Rock when I ran. I did not see him but my assumption was he would have heard my car. I only ran two sessions as my goal was to test the car.

I really don't think the car is appreciable louder but I just wanted to be clear, he was testing but I do not know if he tested my session on track.

Another point to emphasize, people keep mentioning straight pipes. You cannot put a straight pipe in the place where the factory cat is. Look at a cat. The holes are not on opposite ends of the cat cans.

If you decide to cut the cat out you will end up with a shop having to fabricate a jig to hold the entire piece, cut the cat out and weld in a BENT pipe. That or just fab up a pipe for the whole cat section, but it will have to have various bends too.

This is not actually simple or cheap. Of course Fabspeed has a solution but it is $800.

If you guys meant "straight pipe" in the "no cat" context, then I understand but we may be confusing the term to some.

JohnPG

Scott, just gutted the cans for now. Had been planning on addressing exhaust this winter. Still on that schedule. Will need to put together a system which will accomodate straight pipe and mufflers for the sound restricted tracks.

Dave, car has 42,000 miles.

It was good meeting you at Calabogie, looks like I'll see you again at Mont Tremblant in Sept.

BTW, off topic, the fuel pump didn't die at Calabogie it was one of the hoses attached. Not the one which had failed on Scott's car last year. My mechanic hasn't sent a pic of it yet.

When I get the pic I'll post. Going forward I'll have a spare pump in the trailer.

SH || NC

Yeah, when I say straight pipe I mean 'straight through'.


Sorry to hear it John. Yeah, having a whole pump assembly (the revised 996 unit) would be great as a whole fix at the track, then you could repair the damaged unit at another time.



The modular exhaust system sounds like a great idea where you encounter different restrictions; all VB clamps makes for easy 'remove & replace' swaps.

I don't have to worry about that too much for teh tracks I visit, but if I did, I would consider the following setup:

• sport exhaust with valving kit
• cat bypass
• a set of equal length headers to complete it perhaps

Quiet(ish) when you need to be; loud when you don't, and push-button convenience. Not cheap, but would be nice.

SH || NC

Just stumbled across this post as well John. Near you; perhaps worth checking out. They have turn down tips as well; modular. (link)

DHI

Speedtech can make any number of variations wit/without cats or cans... here is some info from the other forum...

http://www.6speedonline.com/forums/g...ml#post3605830

StevoUK

Just re-read this, the startup rattle could be the timing chains tensioners - the chains rattle until the oil fills up and tensions the chains - leave the car a few days and the oil drains out of the tensioners and causes the rattle.

It goes away in a few seconds.

JohnPG

Stevo,

The start rattle was definitely the cats. Once they came out rattle was gone. The rattle sound like a couple of tin cans knocking around.

Dudley

The owner of Speedtech is a Rennlister, John D II.
A great guy.

JohnPG

Thanks Dave and DHI,

I'll certainly check with Speedtech this winter. A track friend of mine just got an exhaust from them this year. If you go to their site his car is the silver Mk1 in the videos. I'll be with him at WGI on the 24th and take a closer look at the system. What ever I end up with will have to accomodate an open setup and a mufflered setup, most likely using the VB type clamps Scott refered to.

DHI

I just had my stock cats with 26,000 miles checked (boroscope) and all is good.

Ur20v

A better answer is that dust is the insulation material from between the inner and out cat casings as these are double skinned and use the insulation for three reasons, noise, quick cat monolith light up times and lastly to reduce surface and radiated heat to minimise the chance of setting fire to grash/scrub if parked in a field.

Have a look at the photo and the 'tan' coloured filling.

Cheers
Jay

CT03911

I figured a quick update to this thread might help. I did this cat mod last fall. I am not positive how many track days I ran after it but it was a good number.
I have not had and CEL lights. The car runs strong again. I have not been black flagged at our crazy noise sensitive LRP.
From under the car, or in the engine bay, this setup looks stock. I just went to CT emissions testing and had no issues.
I am a bit surprised I never got a CEl all last fall. I do drive some around town, down to get gas after a track wash etc etc. I guess I don't drive it enough around town to trigger a code.
For now, the car has a CT emissions check and is running like new so I am good to go for 2013 season.
I suppose for those of you who drive more street miles this may not work if it eventually throws a code but for me the cat gutting and radiator cleaning last fall has worked really well.
Time will tell this season if I throw a code eventually but getting the performance back and through emissions was my concern.
So far, so good.
I have the original O2 sensors still too.

Wayne K

I have a noise in the exhaust on cold start for usually less than a minute but was told that it was an air pump for emissions.