Cat Converter Flow

[silverr34gtt]

Hi Guys,

Iv got a r34 making around 250Kw @ the wheels.

My exhaust is 3 inch turbo back, HKS dump, HKS front pipe, jjr cat, Trust PE 2.

Would the jjr cat be ok for this application. Has anyone had a problem with a jjr cat?

Its the only chinese part on my exhaust and i was wondering if i should upgrade it.

Cheers

[khunjeng]

Hi Guys,

Iv got a r34 making around 250Kw @ the wheels.

My exhaust is 3 inch turbo back, HKS dump, HKS front pipe, jjr cat, Trust PE 2.

Would the jjr cat be ok for this application. Has anyone had a problem with a jjr cat?

Its the only chinese part on my exhaust and i was wondering if i should upgrade it.

Cheers

do they quote CFM or flow? that will answer ur question, if ur stressed take it off and de-cat...get some flames.

[silverr34gtt]

They say they tested it to 570 cfm.

[khunjeng]

They say they tested it to 570 cfm.

some brands quote some big numbers, saw some tests ages ago somewhere...most we're not as high as they quote. CATCO or Metal Cat were pretty good from memorym Metal Cat are pretty much the premium..

Assuming they are full of shit (better than 75% chance) and 570 isnt a huge number in the scale, you could do better,

[godzl1975]

sorry abit off topic, but how can you tell when a cat is gone????

[Blitz]

Hi Guys,

Iv got a r34 making around 250Kw @ the wheels.

My exhaust is 3 inch turbo back, HKS dump, HKS front pipe, jjr cat, Trust PE 2.

Would the jjr cat be ok for this application. Has anyone had a problem with a jjr cat?

Its the only chinese part on my exhaust and i was wondering if i should upgrade it.

Cheers

I think you will find they are X-Force Cats, not JJR that Just Jap offers with the 570cfm rating.

[WazR32GTSt]

i think you will find not much (if any) difference between any cat on the market

unless your cat is actually blocked or stuffed in some way then changing form one type of cat to anther will do absolutely nothing

..you may go slightly faster because the car is lighter from the loss of money in your wallet, that's about all..

[limpus]

I actually went from an X-force cat to a metalcat and i got a fair power increase at the same boost level after a tune...202rwkw to 211rwkw...its all because my tuner was able to dial in about 4 more degrees of ignition timing with the better flowing metalcat...if its bothering you just upgrade it...it won't be a downgrade anyway....

[WazR32GTSt]

I actually went from an X-force cat to a metalcat and i got a fair power increase at the same boost level after a tune...202rwkw to 211rwkw...its all because my tuner was able to dial in about 4 more degrees of ignition timing with the better flowing metalcat...if its bothering you just upgrade it...it won't be a downgrade anyway....

fine, but 100% of the upgrade came into the tuning of the car

i'm sure you could have dialled more timing into the original system and still have seen a power increase

that, and 10rwkw can be accountered for between days and intake temps.

i'm not convinced.

[Munkyb0y]

I actually went from an X-force cat to a metalcat and i got a fair power increase at the same boost level after a tune...202rwkw to 211rwkw...its all because my tuner was able to dial in about 4 more degrees of ignition timing with the better flowing metalcat...if its bothering you just upgrade it...it won't be a downgrade anyway....

i had a similar experience. went from an xforce ceramic high flow cat to a stainless internal highER flowing cat.

my tuner also said he got more power coz of less restriction. there was an immediately noticeable midrange gain when driving it right after the tune.

if you ask me, it makes a substantial difference.

Edited October 15, 2007 by Munkyb0y

[WazR32GTSt]

dyno graphs?

the flux capacitor i installed in my V35 made heaps more midrange but you'll have to take my word for it

Edited October 15, 2007 by WazR32GTSt

[Munkyb0y]

dyno graphs?

the flux capacitor i installed in my V35 made heaps more midrange but you'll have to take my word for it

dyno numbers, temps, settings etc aside...

there was an immediately noticeable midrange gain when driving it right after the tune

get my point? thats not something you can fudge on the dyno

Edited October 15, 2007 by Munkyb0y

[limpus]

Here is the dyno graph as proof...final power was alittle more because boost was turned up even more after the initial 211rwkw run...

Now...fair enough the concrete visible power gain came from the tune...but i did immediately notice a gain in midrange after the new cat...and that was with a large resonator put in at the same time...as for being able to dial in more timing...well...thats the thing...we couldn't...it would just start detonating...we were scratching our heads on this one for awhile...and i bit the bullet and changed the cat as i was suspicious of it all along...anyway...take what you will from this...i'm just saying that its not that inconceivable...and i know i'm convinced...

[WazR32GTSt]

you've admitted that

a) you've upped the boost

b) you've had a tune

i appreciate that you have the graphs and at the end of hte day if your old cat didn;t enable to you tune it properly then its fair enough

and as i said in post #7 "unless your cat is actually blocked or stuffed in some way" which is clearly what yours was if it was causing the car to detonate

but i strongly believe for someone with a working cat of any brand, changing to a different one isn't going to do squat. obviously changing from a 1" cat to a 4" cat is going to but that's not what we're arguing here. we're arguing same diameter cats but one of a different brand with a slightly higher cfm rating..

yet to see solid proof in my 4 years having a skyline and browsing the forums

i went from a 3" GUTTED cat to a 3" x-force and noticed NO difference in power whatsoever.

Edited October 15, 2007 by WazR32GTSt

[666DAN]

MetalCAT brand cats are only good for about 100kms though aren't they? I've seen 5 of them delaminate from the internals with a minor misfire on the dyno.

Magnaflow metal substrate all the way!!!!

I'm with Warrren, going from a 3" highflow ceramic to 3" highflow metal did didly on the squat meter...didn't notice a thing.

[BAMR33]

i went from a 3" GUTTED cat to a 3" x-force and noticed NO difference in power whatsoever.

Just wondering metal or ceramic?

[WazR32GTSt]

no idea, it was a 3" x-force "high-flow" if it helps

[limpus]

I see where you're coming from too mate...the thing about my Xforce cat is...the guy who took it off asked me why i was changing it because it was in perfect nick and apparently a "high flowing" item as well...even without a retune i immediately noticed a increase in midrange and the car came on boost so much quicker...so in my case...even though the old cat was in perfect nick...the metalcat still made a noticeable difference...i personally wish i didn't have to spend almost $400 for the metalcat but at least it was worth it in my case...

[Munkyb0y]

lol, limpus i swear i'm not copying you. but i had the same experience. when i put the xforce ceramic on, my car actually felt laggier, less responsive, and developed a crazy drone around 2k rpm. i took it off, went back to the old one. then replaced that with a stainless internal highflow, and bam, better response, better everything. thats my personal experience, not my opinion.

[limpus]

Glad to know at least a few other people have had similar experiences...the difference to me was noticeable even though i had a slightly restrictive resonator put on at the same time...not to say the Xforce cats are bad...but when chasing bigger power it makes sense to get the highest flowing item on there...then again...we could always decat the thing but thats illegal so i won't suggest it...lolz...

Edited October 15, 2007 by limpus