[alfski]

My car is a 91/2 on a J plate so does not require the catalytic converter which is fitted. It also has a hole/ crack in the join somewhere in the centre of the system. There are many systems available but I wondered if anyone had fitted a non cat single silencer system? More free flowing and hopefully a little louder? I don't want a droning thrum but it won't do much motorway mileage so a little noise would be good. I was hoping to liberate perhaps five/ ten extra horses in the process?
My question really is has this been done before and is there a well trodden path to follow or is it a get a system made by a specialist? Thanks, John.

 

[spiderserie4]

If you do decide to remove the cat the O²/Lambda sensor needs to be put back on the exhaust.
....as you know from an earlier post of yours on this same subject.

I doubt you'll get 10 horses!

I'd keep the cat....our already contaminated air will thank you, as will your kids

If you want extra power fit a squadra chip and for a slightly louder rasp, replace the rear silencer section with a straight through section.

but each to his own, of course.

 

[alfski]

Extra horses from the cat removal was not the primary reason for deleting it. A more free flowing system with a better sound is the primary objective. Deleting the rear silencer for a straight through pipe appears to be the simplest solution from my brief perusal under the car.
I looked on the bay of evil for a squadra chip that you mentioned but non listed? Is this a specialist company? Worthwhile modification? Power is not the real goal but a few more horses are always welcome.

 

[swq4]

Squadra are Dutch - see Spider 2.0 i.e., Alfa Spider type 4 - Squadra Tuning

 

[alfski]

So a small increase in bhp but a more useful increase in torque. Looks a good thing. Standard air filter set up looks more than up to the job power wise. Is there an alternative people use to the standard that improves flow or are the after market air filter set ups just for show and induction roar?
With a cat removed, free flowing straight through/ small centre silencer and a chip from squadra it should be possible to see a 12 bhp increase in power- or ten percent, which will probably put my 100,000 mile engine back to pushing something near its original power figure when it was made allowing for the wear and tear.

 

[FrenchSpider]

Alfaholics claim an addition 10 bhp from their stainless exhaust system.

Alfaholics Stainless Steel Sports Exhaust System 1750/2000 - LHD Shallow Floor & All RHD

 

[Joe90GT]

Alfaholics claim an addition 10 bhp from their stainless exhaust system.

Alfaholics Stainless Steel Sports Exhaust System 1750/2000 - LHD Shallow Floor & All RHD

9% increase - that's quite a jump however you've still only got 125 bhp, is it really worth it unless your going racing, bet its sounds nice tho

 

[Joe90GT]

So a small increase in bhp but a more useful increase in torque. Looks a good thing. Standard air filter set up looks more than up to the job power wise. Is there an alternative people use to the standard that improves flow or are the after market air filter set ups just for show and induction roar?
With a cat removed, free flowing straight through/ small centre silencer and a chip from squadra it should be possible to see a 12 bhp increase in power- or ten percent, which will probably put my 100,000 mile engine back to pushing something near its original power figure when it was made allowing for the wear and tear.

After market air filters will only make a tiny difference on way or the other but they do sound rather nice and that must be worth at least 20 mph .........

 

[alfski]

The stainless exhaust looks lovely and I'm sure it has some bhp gains but there are gains to be had considerably cheaper in steel and free flowing with one silencer and no cat. Combined with a squadra chip and the removal of the belt driven fan for the radiator and replacement with an electric one I think maybe 15 bhp perhaps a little more could be released for less than four hundred quid. Each change is reversible. The little extra power will make the car just a little more brisk. The air filter would be cheap but without gain in power and probably not much improvement in sound as the exhaust will be louder.

 

[spiderserie4]

Combined with a squadra chip and the removal of the belt driven fan for the radiator

although one presumes your S4 already has two electric fans....

 

[alfski]

You are absolutely correct. I was thinking of a different car altogether......