ACT Stainless manifolds w/sport CATs - Perfrmance increases?

[Shorty123]

Anyone fitted these items, with or without the cats? is there any noticable performance / sound increases than the standard items?

Ta Shorty

[Zippee]

I've got the de-catted ACT stainless manifolds on my Chim.
No power change from what I can tell and TBH no change in noise either. They do look nice through the bonnet slats when polished up though.

Some people do believe the de-cats make the exhaust louder but I couldn't tell the difference.

[2Munkys]

If you're talking about the ACT 1 5/8" bore manifolds then 'yes' they make a difference. There's an increase in torque, especially in the mid-range. They were an improvement on the original Magnex items which I had non-reverse-coned too. I've seen the comparisons on the rolling road but I can't quote you exact figures. Without the pre-cats there is a slight hike in noise but it sounds fine.

I'm waiting for the catless 'Y' piece to complement the above and after speaking to V8D last Friday they see increases of between 2 and 5 BHP on their 5.4's. Dunno what the effect on a smaller capacity engine would be. I'm just hoping to God that it aint gonna sound overly loud. There's a huge difference between sounding 'good' and sounding 'loud'.

[Shorty123]

2Munkys said:

If you're talking about the ACT 1 5/8" bore manifolds then 'yes' they make a difference. There's an increase in torque, especially in the mid-range. They were an improvement on the original Magnex items which I had non-reverse-coned too. I've seen the comparisons on the rolling road but I can't quote you exact figures. Without the pre-cats there is a slight hike in noise but it sounds fine.

I'm waiting for the catless 'Y' piece to complement the above and after speaking to V8D last Friday they see increases of between 2 and 5 BHP on their 5.4's. Dunno what the effect on a smaller capacity engine would be. I'm just hoping to God that it aint gonna sound overly loud. There's a huge difference between sounding 'good' and sounding 'loud'.

I am talking about the bespoke stainless manifolds with the new Y peice and removable CAT cans, not the polished OEM items. i think the entire setup from ACT including 2 race CATs comes to £1285+VAT


A torque improvement would be good to give better driveability, im not expecting a big hike in power. would love to know what the CATless system sound like and how easy the interchangeable units are fitted in time for the MOT.

Ta

[Wildfire]

I have the full system on my car with the ACT Cherry bomb system and it sounds excellent and the car really does go well.. Thenick has converted to the same and there is definitley an increase in noise when switching out the Pre Cats and Main Cat. To get the bypass pipes out and the cats in for the MOT, you're talking a 10-15 min job. 5 17mm bolts per unit.

Why don't you ring Tim Lamont at ACT to ask about the performance? There is Rolling Road data that shows that the car gets a performance increase with the manifolds, but I can't remember what it is.

[Shorty123]

Wildfire said:

I have the full system on my car with the ACT Cherry bomb system and it sounds excellent and the car really does go well.. Thenick has converted to the same and there is definitley an increase in noise when switching out the Pre Cats and Main Cat. To get the bypass pipes out and the cats in for the MOT, you're talking a 10-15 min job. 5 17mm bolts per unit.

Why don't you ring Tim Lamont at ACT to ask about the performance? There is Rolling Road data that shows that the car gets a performance increase with the manifolds, but I can't remember what it is.

Thanks wildfire i'll give Tim a call

[2Munkys]

Yup, sorry Shorty, I recognised we weren't talking the same thing after I hit the send button.

I think the manifolds are pretty much the same however and the reduction in bore is where the benefits lie enabling the motor to scavenge more effectively.