Decat Dyno Results - With Or Without Cat? Power Gains?

[l_uk3y]

True. But we do have a fairly solid track emphasis on this site with a lot of people either using their cars part time on the track or building full time track cars. The comparison is definitely warranted as not everybody wants to do the wrong thing by using no cat on the street. If they do, Bad luck if you get caught.

[Duncan]

oh yeah I forgot to mention, flames and pops are cool. we are all kids inside, some just hide it better than others.

[Cartman]

great power gain results hypergear, but you failed to mention the 6psi boost difference between runs, and i'm suprised no one else mentioned it...

[MBS206]

My car melts cats... Lucky I stick to the track!

The comparison also, for those doing non cat, to cat testing should be done with a brand new cat.

A mildly collapsed cat will rob massive amounts of power!

[GTR Grey Ghost]

This was a good upgrade over the factory cat which was replaced as it had signs of internal cracking, also the sound opened up nicely.

[NSNPWR]

Yeah, I should add, my previous ride was quite alot louder aswell after decat!...

[GTR-32U]

This was a good upgrade over the factory cat which was replaced as it had signs of internal cracking, also the sound opened up nicely.

Nice looking bit of gear.....Who is it made by ?

[geraus]

im running a gutted cat as well feels a bit more louder .. hmmm

[GTR Grey Ghost]

Nice looking bit of gear.....Who is it made by ?

Hi there NSNPWR, the cat is a Metal Type X-Force which works well, reiterating this is the Canon Version, I would not even consider the flat bodied at all. I the original pics you will see the heat shield, well if you purchase this be aware that the heat shield faces up toward the car as it should, cheers

[GTR Grey Ghost]

Hi there NSNPWR, the cat is a Metal Type X-Force which works well, reiterating this is the Canon Version, I would not even consider the flat bodied at all. I the original pics you will see the heat shield, well if you purchase this be aware that the heat shield faces up toward the car as it should, cheers

Part Number <LI>ES-NS-13-CAT-B3 metal hiflow cat [32cm long / 4 1/2" round]

http://www.bestmufflers.com/bshop/index.php?cPath=329

[femno]

great power gain results hypergear, but you failed to mention the 6psi boost difference between runs, and i'm suprised no one else mentioned it...

exactly my thought. the boost should have been turned back down for a true comparison.

having said that ive seen ~5kW gain at peak power and 500rpm boost response left shift doing back to back runs on a ~280kW setup, having turned the boost down to match the first run.

[GTR Grey Ghost]

I had a look at the dyno again, you are referring to the manifold boost pressure, nothing wriiten on the second run relating to boost? maybe I am reading it wrong

[noone]

Wouldnt dynoing with a decat give more acurate results as far as AFR's go

or do cats actually do nothing to effect what come outa the tail pipe ???????

[GTR Grey Ghost]

Wouldnt dynoing with a decat give more acurate results as far as AFR's go

or do cats actually do nothing to effect what come outa the tail pipe ???????

Yes pretty sure that with the CAT the AFR would be more accurate, however the question was .....how much power is achieved without it, we are not talking about tuning the car without the cat but merely identifying the robbing power effect from hang it and if some had removed it for interested on the dyno and what difference / increases if any did they achieve.

Under not circumstances are we suggesting that a Cat be removed off of a road car, was a topic of conversation between mates is all, read the initial post, cheers

[MBS206]

Wouldnt dynoing with a decat give more acurate results as far as AFR's go

or do cats actually do nothing to effect what come outa the tail pipe ???????

A better place for AFR reading is actually in the dump pipe. With and without a cat, the AFR readings vary from front to rear of the exhaust.

My car is tuned with the AFR taken around 2 to 3 feet after the turbo.

And from a good quality, good condition high flowing cat, to no cat, there will be a minimal power gain (Talking 5RWKW max) but others will say "But I got 50RWKW from removing mine!" but they fall into the category of either:

Too small of a cat

Low quality cat

Non Highflow cat

Partially collapsed cat (Bad condition)

[noone]

Yes pretty sure that with the CAT the AFR would be more accurate

so the cat has no effect on emissions then an is pointless???

Sorry if you thought I was off topic an I guess I was

was just interested to see if others thought Decat was a worthwhile thing to do during tuning runs

A better place for AFR reading is actually in the dump pipe. With and without a cat, the AFR readings vary from front to rear of the exhaust.

My car is tuned with the AFR taken around 2 to 3 feet after the turbo.

Agree this is the best way however most are done from the tailpipe

[r32gtr92]

guys bit off topic but saw the 20k fine and wanted to ask? my car is currently on defect and im going to regency soon (adelaide defect inspection place ), now im pritty sure my cats been gutted cause a flame or to has come out my zorst, if they find out that it infact has been gutted will i get fined straight away?

sorry to highjack the thread :{

cheers

[MBS206]

guys bit off topic but saw the 20k fine and wanted to ask? my car is currently on defect and im going to regency soon (adelaide defect inspection place ), now im pritty sure my cats been gutted cause a flame or to has come out my zorst, if they find out that it infact has been gutted will i get fined straight away?

sorry to highjack the thread :{

cheers

Change it before going for inspection.

Put a compliance cat in.

You want it 100% legal when you go for an inspection.

[GTR Grey Ghost]

guys bit off topic but saw the 20k fine and wanted to ask? my car is currently on defect and im going to regency soon (adelaide defect inspection place ), now im pritty sure my cats been gutted cause a flame or to has come out my zorst, if they find out that it infact has been gutted will i get fined straight away?

sorry to highjack the thread :{

cheers

I am starting to regret starting this thread and reiterate UNDER NO CIRCUMSTANCE RUN YOUR ROAD CARS WITHOUT A CAT.....if you are running without one, put a decent one back on and stop skimping on cash, most of the lads I know are making some decent power and if they loose a few KW from (legal compliance with a CAT) they could not care a less, reiterate they could not care a stuff if they lost 25KWATW, this would be a different story on the track where every KW matters, not on the street......NOT on the street

BUY A DECENT CATALYTIC CONVERTOR..........and do not attend inspection centres without one, remember that its the minority that makes it bad for the majority us, think of the HOON stigma, just a few dipsticks out there make it bad for all of us!

[Kaido_RR]

Video option did a back to back dyno test of an r34 gtr (may have been the top secert gtr can't remeber) with no cat then apexi high flow cat, no cat only made 7hp more. I try and find the video link. Btw this was no light tune gtr it was making upwards of 600hp