Exhaust system's

Level 10 User Joined: 18 Jun 2004 Posts: 614

Right had to re-fit the Cat today, due to MOT soon. Well i've lost some of my top end power i.e 5000 rpm plus. but I've gained more torque lower down 2500-5000 rpm. Seem's to make the car quicker where you need it. I took Ben for a little ride in it last night before I re-fitted the Cat. Did'nt get room to fully open it up, Only 3rd Rolling Eyes

. And the road's had naff all grip with all the damm salt Mad

. But why does the engine make more torque lower down when it got something to work against in the exhaust system ?

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

In effect the back pressure prevents the cyls overscavenging.

It acts as a blockage so less raw fuel goes down the exhaust at lower rpm's.

Level 10 User Joined: 18 Jun 2004 Posts: 614

Ah bit more fuel in the cyls to burn at low rev's then.

Site Subscriber Joined: 10 Jun 2004 Posts: 2317

I take it your keeping the cat on then?

Level 10 User Joined: 18 Jun 2004 Posts: 614

Yep Had a year of fun. So might be selling a stainless De-Cat soon.

Site Subscriber Joined: 07 Oct 2004 Posts: 2281

Keeps the burn in longer!

Site Subscriber Joined: 10 Jun 2004 Posts: 2317

So in thoery mpg should go up a bit..

Level 10 User Joined: 18 Jun 2004 Posts: 614

If I get good perfprmace I don't care about MPG. But something like the old man 2.0 sierra when he had it. the Pinto one. Load's of fuel and naff all performance. Come on Ben your the only one on here who as heard the car before I put the cat back on. Valver's with just one back box on sound awesome.

FCS Event Manager Joined: 04 Jan 2005 Posts: 3680

Mad Pierre wrote:

Yep Had a year of fun. So might be selling a stainless De-Cat soon.

let me know if u do, i'll have it off ya

Level 10 User Joined: 18 Jun 2004 Posts: 614

Heh will do. But if your exhaust is loud now. It be mega loud with a De-Cat.

Site Subscriber Joined: 10 Jun 2004 Posts: 2317

I found that a decat didnt do much to increase the noise of my exhaust..

FCS Event Manager Joined: 04 Jan 2005 Posts: 3680

It's loud, stainless steel from the cat back at the mo.
Not a stupidly oversized bore on the backbox, 2 inch pipe, can't stand those huge 4 inch big bore efforts.

Site Subscriber Joined: 13 Oct 2004 Posts: 4722

is it me...or is your "19" logo a bit scewwiff?

FCS Event Manager Joined: 04 Jan 2005 Posts: 3680

never noticed it being skewiff when looking at the back of the car, maybe its the lighting in the pic makes it look odd.

Level 10 User Joined: 18 Jun 2004 Posts: 614

Then it will sound a bit like this.

http://www.madpierre1.plus.com/vids/VALVER/pierre.wmv

Right click save as

FCS Event Manager Joined: 04 Jan 2005 Posts: 3680

Nice!!

so more about the vid.

mods to car and time for the 1/4 mile was ?

Site Subscriber Joined: 04 Mar 2005 Posts: 116

sounds good

Level 10 User Joined: 18 Jun 2004 Posts: 614

that was 16.5. I have done 15.8 with seat's removed. the 17's do slow it down.