3" cat replacement pipe needed ASAP!

[Race__24]

hey,

if your cat pipe made f*** all difference i'd be putting the thing back on, big fine if you get caught. Around the $10k mark i think.

[Nozila]

be careful driving it on the road without a cat.

[Bl4cK32]

Its not the pipe that didnt make *** all difference, its the fact the cars timing is off. Its 1 tooth out or so on the timing is why it didnt make any more power.

The new exhaust with the cat replacement pipe did help it make more in the top by about 10 - 15rwkw....

[skyline]

To ALL,

It was noted several years ago that a high flow cat will flow exactly the same as a race pipe,this was tested by Martin Donnon in zoom and done courtesy of someones flow bench here in adelaide.FOOD for thought!

Regards,

SKYLINE (Kym)... :werd:

[sky30]

I had a 3" high flow cat on my car, by replacing it with a straight through pipe it made an extra 15rwkw....

I dont think it is posible for any cat to flow aswell as straight through pipe, this is very obvious when looking inside a cat.

[Chris32]

A flow bench, as far as I know, can't pump through stinking hot expanding exhaust gas, so a flow bench test on a straight thru pipe vs a high flow cat is about as helpful as tits on a bull.

Makes a good magazine article though

A good example is forum member Roy, by replacing his 'high flow' cat with a straight pipe, he picks up about 20dd rwkw from memory

[Bl4cK32]

The only reason i went with the cat replacement pipe was a time vs. cost factor. IE the $40 the pipe cost (thanks nightcrawler ) or the $550 odd for the highflow cat.

Can anyone really tell a 10-15 rwkw difference (seat of the pants) driving their car?

[Chris32]

Sure, take 3 degree's timing out on your H/C, see how flat it feels that should represent a power drop of around 15odd rwkw

[Bl4cK32]

no worries....point taken

[Chris32]

lol! So hows it sound now mate? Saw you the other week, pulling out of BP down near noarlunga way, I was on my way down to victor

[Bl4cK32]

Sounds damn fine now. Not much louder than before. It doesnt even drone too much either. Im very pleased with it actually. Has a nice rumble to it.

I wish i had it all running properly...was supposed to have it to 200kw @ the wheels already...

[Chris32]

Mine is quite loud now, especially when you are flat out. Not external-gate loud, but still quite loud

Did you end up going the twin 2.5"s?

Its not to droney on the open road though, or I have gone tone deaf, not 100% sure

It will get there mate, is it a timing problem? If it is, have you checked to see if your CAS has all the teeth on it. Shaun had one in there a while ago that I ended up having to pull the exhaust cam and CAS of my spare motor for.

The problem sounded the same, down on power all over, but when it was swapped over it made a extra 25rwkw

How much boost are you running? Whens the big turbs on the cards!!

[Bl4cK32]

Yup twin 2.5" system on and running

Definitly a timing problem (i hope thats all). It should have all the teeth on the cas, as it was working when i had the rb20det still in there.

Shaun fitted a set of STR adjustable cam gears for me when he got my car up and running, so i guess it may have happened then. Joel and my engines were built at the same time, and timing belts were fitted and set by the engine builder. Joels runs fine, where as mine....

From memory Shaun had trouble with it idling (q45 afm), and the cas is fully retarded....hopefully when it goes back next week, it can pick up the extra 50rwkw it was missing

Oh yer only running 0.8 bar atm. The big turbs....well saving for a house deposit is sort of killing me atm as well as far as mods go

[Chris32]

Definatley sounds like its a tooth out on the timing, with the CAS fully retarded etc.. should pick up some power when thats fixed

I know what you mean about trying to saved cash up, its hard hey!

[Bl4cK32]

Definatley sounds like its a tooth out on the timing, with the CAS fully retarded etc.. should pick up some power when thats fixed

Tuned yesterday, but more problems came up will let you know....

Check the r33 rb30 thread for more details etc....