I noticed while making a Z vid that some soot comes out of my exhaust when getting to about 3500-4000 revs. Its not smoke its deffinatly soot. What can this mean? Is it just soot from inside the exhaust? Or could it mean I am running rich?

 

 

Stuart

I reckon mine used to do that and I think it was soot that builds up in the cats. Most turbo engines do run a little rich anyway but mine has definitely improved after replacing the cats and replacing the PCV valves. Fuel comsumption is also reduced but part of that is also due to ther manual box. About a 10% increase I reckon, must try with Optimax one day ...

You must try Optimax. I wasnt taking all the hype, but my engine runs smoother, I get avout 2-5mpg more, depending on long/short drives.

I used it for a few weeks when it first came out and thought it was good, but went back to unleaded. About 4 months later I tried Optimax and with in a few miles the car was running smoother and more responsive. Now 95% of the time I use Optimax. Only time I dont is when I cant find a Shell Garage!

 

I suggest you try it.

 

StUART

well the Optimax thing has been proved already by EVO magazine. Bck to back testing.

 

I think its just running a bit rich , maby because of the launch control?

 

I've used Optimax for quite a while and to be quite honest I don't see any difference. One time I filled up with Q8 standard unleaded the car drove smother and more responsive. I own a 94 tt u.k specs. So why does everyone hype up Optimax?

I ran Optimax for a few weeks. Did seem to be more responsive..but did notice more black deposits building up quicker on tips of exhaust to standard unleaded.

Mind you I run an Import 300TT...I did hear that because it's an import I should run a higher octane fuel like Optimax cos the standard UK fuel can reduce the BHP up to 20HP...think Luke at Z centre mentioned that.

If you think you could be running rich you might as well do the O2 sensor test, only take you a few mins. See twinturbo.net tech section. Otherwise I think it's normal to get a bit of soot if you don't blast the car often enough.

 

Jez.