Just had hi-flow cats fitted and these are my thoughts
Discussion
Hi Guys
I've just had a pair of high flow cats (200 cell) custom fitted to my Monaro VXR LS1 by EMP Performance (formally known as Top Gear) of St Albans, Herts. They cost £500 fitted. I expect that I could have got them cheaper if I'd shopped around but EMP are very local to me. The cats are made by Power flow.
My Monaro is standard apart from a Wortec cat back exhaust. I just fancied fizzing up the sound a bit but not too much as it's my daily drive and this seemed like a sensible option. What I've found is that with the hi-flow cats, the exhaust is more raspy between gear changes and on the overrun which I love. It pops and bangs just the same as before but a bit louder. The overall volume of the exhaust has increased slightly with the note having a slightly harder edge. Regarding the boom characteristics, the classic LS boom at 1800rpm has increased in proportion with the rest of the exhaust sound level but the boom point at 1000rpm i.e. when driving in grandad mode in 6th gear at 38mph has vanished!! Of course it took me quite a few days to discover the latter.
For me it's been a very worthwhile mod.
A big thanks to Wozza and Mikeyb1987 who gave me some very sound advice (they both have high flow cats on their Monaros).
Jon
I've just had a pair of high flow cats (200 cell) custom fitted to my Monaro VXR LS1 by EMP Performance (formally known as Top Gear) of St Albans, Herts. They cost £500 fitted. I expect that I could have got them cheaper if I'd shopped around but EMP are very local to me. The cats are made by Power flow.
My Monaro is standard apart from a Wortec cat back exhaust. I just fancied fizzing up the sound a bit but not too much as it's my daily drive and this seemed like a sensible option. What I've found is that with the hi-flow cats, the exhaust is more raspy between gear changes and on the overrun which I love. It pops and bangs just the same as before but a bit louder. The overall volume of the exhaust has increased slightly with the note having a slightly harder edge. Regarding the boom characteristics, the classic LS boom at 1800rpm has increased in proportion with the rest of the exhaust sound level but the boom point at 1000rpm i.e. when driving in grandad mode in 6th gear at 38mph has vanished!! Of course it took me quite a few days to discover the latter.
For me it's been a very worthwhile mod.
A big thanks to Wozza and Mikeyb1987 who gave me some very sound advice (they both have high flow cats on their Monaros).
Jon
Looks slightly tapered from the header which I wouldn't be happy with in truth. Might be something to chat to them about.....
Also for the 'free-flowing' cat boys, we found in racing that actually removing the cats lost us power and speed overall. Weird but a fact!!!!
Also for the 'free-flowing' cat boys, we found in racing that actually removing the cats lost us power and speed overall. Weird but a fact!!!!
Edited by TheLeatherman on Saturday 11th October 08:26
TheLeatherman said:
Looks slightly tapered from the header which I wouldn't be happy with in truth. Might be something to chat to them about.....
Also for the 'free-flowing' cat boys, we found in racing that actually removing the cats lost us power and speed overall. Weird but a fact!!!!
Not sure about the zero-cell cats, but I got the impression the centre-box delete cost me power, so I can believe it (in an NA application).Also for the 'free-flowing' cat boys, we found in racing that actually removing the cats lost us power and speed overall. Weird but a fact!!!!
Edited by TheLeatherman on Saturday 11th October 08:26
Jon Jon said:
Hi Guys
I've just had a pair of high flow cats (200 cell) custom fitted to my Monaro VXR LS1 by EMP Performance (formally known as Top Gear) of St Albans, Herts. They cost £500 fitted. I expect that I could have got them cheaper if I'd shopped around but EMP are very local to me. The cats are made by Power flow.
My Monaro is standard apart from a Wortec cat back exhaust. I just fancied fizzing up the sound a bit but not too much as it's my daily drive and this seemed like a sensible option. What I've found is that with the hi-flow cats, the exhaust is more raspy between gear changes and on the overrun which I love. It pops and bangs just the same as before but a bit louder. The overall volume of the exhaust has increased slightly with the note having a slightly harder edge. Regarding the boom characteristics, the classic LS boom at 1800rpm has increased in proportion with the rest of the exhaust sound level but the boom point at 1000rpm i.e. when driving in grandad mode in 6th gear at 38mph has vanished!! Of course it took me quite a few days to discover the latter.
For me it's been a very worthwhile mod.
A big thanks to Wozza and Mikeyb1987 who gave me some very sound advice (they both have high flow cats on their Monaros).
Jon
Why not 100 cell!I've just had a pair of high flow cats (200 cell) custom fitted to my Monaro VXR LS1 by EMP Performance (formally known as Top Gear) of St Albans, Herts. They cost £500 fitted. I expect that I could have got them cheaper if I'd shopped around but EMP are very local to me. The cats are made by Power flow.
My Monaro is standard apart from a Wortec cat back exhaust. I just fancied fizzing up the sound a bit but not too much as it's my daily drive and this seemed like a sensible option. What I've found is that with the hi-flow cats, the exhaust is more raspy between gear changes and on the overrun which I love. It pops and bangs just the same as before but a bit louder. The overall volume of the exhaust has increased slightly with the note having a slightly harder edge. Regarding the boom characteristics, the classic LS boom at 1800rpm has increased in proportion with the rest of the exhaust sound level but the boom point at 1000rpm i.e. when driving in grandad mode in 6th gear at 38mph has vanished!! Of course it took me quite a few days to discover the latter.
For me it's been a very worthwhile mod.
A big thanks to Wozza and Mikeyb1987 who gave me some very sound advice (they both have high flow cats on their Monaros).
Jon
Hi James
I didn't go for 100 cell for 2 reasons;
Firstly, I only wanted a small increase in sound level owing to my car being my daily drive and 100 cell cats MIGHT have proved too loud for me,
Secondly, I wanted to be sure it got through the emissions part of the MoT as I understand 100 cell cats can sometimes cause problems in that area.
Jon
I didn't go for 100 cell for 2 reasons;
Firstly, I only wanted a small increase in sound level owing to my car being my daily drive and 100 cell cats MIGHT have proved too loud for me,
Secondly, I wanted to be sure it got through the emissions part of the MoT as I understand 100 cell cats can sometimes cause problems in that area.
Jon
Jon Jon said:
Hi James
I didn't go for 100 cell for 2 reasons;
Firstly, I only wanted a small increase in sound level owing to my car being my daily drive and 100 cell cats MIGHT have proved too loud for me,
Secondly, I wanted to be sure it got through the emissions part of the MoT as I understand 100 cell cats can sometimes cause problems in that area.
Jon
On issue with MOT and Cats is if Your Super charged I didn't go for 100 cell for 2 reasons;
Firstly, I only wanted a small increase in sound level owing to my car being my daily drive and 100 cell cats MIGHT have proved too loud for me,
Secondly, I wanted to be sure it got through the emissions part of the MoT as I understand 100 cell cats can sometimes cause problems in that area.
Jon
And even then you just have to get them hot
TheLeatherman said:
Looks slightly tapered from the header which I wouldn't be happy with in truth. Might be something to chat to them about.....
Also for the 'free-flowing' cat boys, we found in racing that actually removing the cats lost us power and speed overall. Weird but a fact!!!!
Myself and r8black don't have that issue.Also for the 'free-flowing' cat boys, we found in racing that actually removing the cats lost us power and speed overall. Weird but a fact!!!!
Edited by TheLeatherman on Saturday 11th October 08:26
TheLeatherman said:
Looks slightly tapered from the header which I wouldn't be happy with in truth. Might be something to chat to them about.....
Hi TheLeathermanEdited by TheLeatherman on Saturday 11th October 08:26
Good spot regarding the tapering! I hadn't noticed until you pointed it out. I have measured the the taper and it goes from 2 3/8" to the standard 2 1/2" diameter. This is far from ideal!!!!! I'll have a chat with them. One thing's for sure, I'm not going to use EMP Performance again!
Jon
Gassing Station | HSV & Monaro | Top of Page | What's New | My Stuff