NEW PERFORMANCE EXHAUST KNOCKING

[martinc92]

HI ALL

I have installed a new 2" sportex performance exhaust as part of my restoration, just got it on the road after 18 months, but the exhaust is knocking on my offside leaf spring AGGHHHHH.

I have fitted new spax gas shockers and ramped them to their hardest then back 5 clicks, but I still have the knocking!!!!

I have approx. 25mm gap between spring and exhaust.

The leaf springs are original and look fine but after other advice I have not installed lowering blocks for this reason.

does anyone have any tips please??

[Terra-Kotta]

Centre box should have two short rubbers. Rear box should be a longer rubber.

Generally these Ashley/sportex/uncle Tom cobbley exhausts take a bit of bending and tweaking to get to fit right.

The only exhausts I've come across that are really any good are janspeeds.

[Bug]

The only exhausts I've come across that are really any good are janspeeds.

Can't beat 'em !

[jimmyted]

Mine took some dicking around to get it right too.

Try swapping the rear hanger so it slots into the rubber the other way round. I think I had mine the wrong way round to begin with and had same problems as you.

[jimmyted]

Wait, i just realised it's on a 2.8.. mine was for a 4 cylinder, it could be totally different!

[-JC-]

The only exhausts I've come across that are really any good are janspeeds.

Can't beat 'em !

No issues with mine - other than joining up my 2nd hand manifold, but I expected that (expected it to be a lot worse tbh!)

[Andrew 2.8i]

Mine took some dicking around to get it right too.

So did the Sportex on my 2.8. Exactly the same symptoms you described. The main bit of jiggery-pokery that solved the issue was to slide the backbox section up at the join with the centre section.
This gave a little more clearance where the exhaust passes closest to the spring.

Andrew.

[martinc92]

all

cheers for your comments,

typical i've put exhaust paste on the joints, its a bxxxxxd to split once hard, but ill try raising it as Andrew says.

[Terra-Kotta]

2 and a qtr inch tube is way too big for a 1.4 3 cylinder engine.

[Andrew 2.8i]

2 and a qtr inch tube is way too big for a 1.4 3 cylinder engine.

Hi,
That's probably true. I believe that the stainless Janspeed system has a smaller size tube (1 and 3/4?). However, for most people it's simply a question of finances. The Sportex complete system, including manifolds is £432 and the equivalent Janspeed system is £701.

Andrew.

[Terra-Kotta]

When I took off the Ashley from the orange one and fitted the smaller bore janspeed I noticed it gained a huge chunk of torque. And a very slight loss in top end Bhp. Felt quicker and probably was because torque is what matters most of the road.

[Andrew 2.8i]

Hi,
I'll just mention that I found that the join between the tailpipe section and the centre section of the exhaust had an overlap of about 160mm, so there was plenty of room to slide the rear section up and clamp it in position.
Another point I'll mention is that I've just fitted new springs and they make they top of the rear wheelarch 595mm from the ground. How does that compare to yours? If your springs are original, they may be sagging a little. Although from the photos on your restoration thread it looks fine, but at least you now have a point of reference for comparison.
Don't you find the ride a little hard with the Spax set as they are? I have mine set about five or six clicks from the softest position, which suits me fine for road use.

All the best,
Andrew.

[martinc92]

Andrew,

Thanks for the info, ill check the measurements and come back to you. ride is a bit hard but just tried to get a happy medium between softer ride and exhaust knocking, to hardening the shockers to limit this.

cheers

mart

[martinc92]

Andrew

removed my rear silencer exhaust section tonight raised it 25mm up on the centre section silencer box joint, this gave me a 12mm increased gap between leaf spring and exhaust pipe. Knocked back the spax shockers 5 more clicks, hey presto knocking vanished with a better ride.

cheers for advice mate.

Mart

[Andrew 2.8i]

Hi Mart,
I'm pleased that you've sorted your knocking exhaust. That 12mm increased gap is about the same as I managed to achieve and it makes the world of difference!
That's the beauty of this forum, whatever issue somebody may have with their car, there is always somebody who has had the problem before and can pass on the solution. Sorted!

All the best,
Andrew.

[Terra-Kotta]

I have not had the problem. I used janspeeds.

[Andrew 2.8i]

I have not had the problem. I used janspeeds.

Hi,
You're right in saying that the quality of the Janspeed is much better then the sportex. I have heard, as I'm sue you have, this complaint often with the Sportex system. Perhaps it's because of the larger tube used makes the exhaust too close to the leafspring.
For the money, the Sportex seems to be a decent enough compromise and sounds fruity without making too much of a drone at high speed.
Terra, can you recommend another performance exhaust system for similar money to the Sportex, or do you suggest that it's best to save up for the Janspeed instead? I have heard it said that the quality of Janspeed has suffered since the components are shipped in from Malaysia, or somewhere. Any truth in that, in your experience?

Andrew.

[Terra-Kotta]

Il be honest. All the sportex Ashley and cci ones I'm convinced come from the same factory. The bore size is just to big and hurts mid range power.

[Andrew 2.8i]

OK, thanks Terra.

[Andrew 2.8i]

Il be honest. All the sportex Ashley and cci ones I'm convinced come from the same factory.

Hi,
You're probably right. I doubt that there are many manufacturers of exhausts in this country that can cope with a production run, as opposed to one-off builds.
The CCI systems used to be made by T.I. Bainbridge in West Yorkshire, but I think that company is no longer trading. Does anyone know who manufactures the exhausts for CCI now?

Andrew.