Which hi flow cats?
Which hi flow cats? Hi,
So I need a bit of advise, I'm planning to add LT with hi flow cats to my 2001 TA with a GMMG catback.
I am not sure if I will pass our UK emmisions test, so want the best filtering cats available.
I guess they may restrict the flow a little, I'll just have to live with it.
I need cats which filter the most pollutants, to reduce the possability of failing the test.
Which brand do you recommend??
So I need a bit of advise, I'm planning to add LT with hi flow cats to my 2001 TA with a GMMG catback.
I am not sure if I will pass our UK emmisions test, so want the best filtering cats available.
I guess they may restrict the flow a little, I'll just have to live with it.
I need cats which filter the most pollutants, to reduce the possability of failing the test.
Which brand do you recommend??
On The Tree
Joined: Oct 2007
Posts: 185
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From: San Jose,Ca
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Thanks for the link 2000ssowner
Hmm, interesting, I didn't realise that.
So all hi flow cats filter about the same??
I see some cats have different materials on the inside, does that not make a difference to flow??
any set of cats will do, its the tune that will either make or break the e-test
So all hi flow cats filter about the same??
I see some cats have different materials on the inside, does that not make a difference to flow??
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Tech Resident
Joined: Jan 2006
Posts: 5,117
Likes: 3
From: Philly
tsp sells a hi flow catted y. heres a link.
http://texas-speed.com/shop/item.asp...d=189&catid=45
http://texas-speed.com/shop/item.asp...d=189&catid=45
Tech Resident
Joined: Jan 2006
Posts: 5,117
Likes: 3
From: Philly
What you want to get are Magnaflow 59959 cats. They are bullet-style metallic core cats. They flow very, very well, take up very little space and aren't too expensive. They're only around ~$100 each, significantly less than other brands. I strongly recommend you do a search on them. Note that if you purchase them, you will have to either construct your own y-pipe as a custom application or buy a y-pipe without cats and weld them in. Most catted y-pipes give you crappy cats. I had a custom y-pipe made with those cats specifically because they're so good.
Yeah, I'm bringing my car over there. I'll be stationed at Lakenheath AFB.
There are some 'friendly' garages around here regarding test.
I'm hopeing to move abroad, so want to comply with the laws regarding emmisions to help make the move easier.
At least untill I get to know where the foreign 'friendly' garages are.
Thanks for the info ChocoTaco369.
I have herd Magnaflow cats are the way to go, but always like to get a 2nd opinion.
Yes I do intend to have a custom y pipe made up, as importing a y is quiet expensive, and the LT's I'm looking at don't have a y pipe option.
Just what I was fishing for, thanks for clarifiying that.
Magnaflow cats it is then.
Thanks for the help.
I have herd Magnaflow cats are the way to go, but always like to get a 2nd opinion.
Yes I do intend to have a custom y pipe made up, as importing a y is quiet expensive, and the LT's I'm looking at don't have a y pipe option.
If you want good cats, you want metallic core bullet-style cats
Magnaflow cats it is then.
Thanks for the help.
Any details on how they test there? Its all over the board in the US as far as emissions testing. There is everything from no testing to, simple OBDII PCM checks, to full on visual inspections where any modifications that change the location of stock exhaust emissions components would be a fail.
Hmmm,
I have last years emissions pass certificate here.
I don't know what it all means, but here ya go:
Fast idle test : Pass
Limits
Engin speed 2500/3000
CO - 0.20 0.02 (%vol)
HC - 200 1 (ppm vol)
*? Limit 0.97 - 1.03 1.012
Natural idle test : Pass
Engin speed 450 - 1500 (Not checked)
CO - 0.30 0.11 (%vol)
*? = symbol I cant rember, it looks like a upsidedown 'y' in the mirror
Thanks for taking a look.
I have last years emissions pass certificate here.
I don't know what it all means, but here ya go:
Fast idle test : Pass
Limits
Engin speed 2500/3000
CO - 0.20 0.02 (%vol)
HC - 200 1 (ppm vol)
*? Limit 0.97 - 1.03 1.012
Natural idle test : Pass
Engin speed 450 - 1500 (Not checked)
CO - 0.30 0.11 (%vol)
*? = symbol I cant rember, it looks like a upsidedown 'y' in the mirror
Thanks for taking a look.
Last edited by taws6; Dec 15, 2008 at 04:41 PM. Reason: added
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
Another option is the Magnaflow/Carsound cats. They quiet the car more than the metallic core bullets. They are also cheaper because they have a ceramic core and are bulkier. I would suspect that they might clean up the exhaust a little better because they are somewhat more restrictive.
I had them installed in my Y-pipe to help kill the rasp with LT's/GMMG.
I had them installed in my Y-pipe to help kill the rasp with LT's/GMMG.
ahh looks like they do a full running test. From what you posted it looks like they test the way used to do here in Chicago before the politics kicked in and they eliminated the rolling test for a simple check the PCM or codes and readiness test. For sure get some Magnaflow Metallic cats minimum. don't get too cheap of a cat though because I had some really cheap $80 a piece spun metallic cats (don't remember the brand) but I failed the rolling test a while back and the cats were only a month old!
"hi flo" cats are a myth. The best cats tested a few years ago were actually stock GM truck cats(3in made for GM by carsound) and even that was marginal. They all flow with in a few percent of each other. There is no need to spend a ton of extra money on anything special
realistically depending on your cam the cats arent going to help you. Im running a 224/228 114+2 and I passed the running tests(barely) but failed the idleing test. Keep it in the 224 range with a high(114 or higher) and you should pass, but if you go with a big cam your probably out of luck.
Magnaflows are decent quality, I think Dynomax's is comparable as well...they did an EXCELLENT job cleaning up the exhaust on my 95 LT1 b-body...but I think the entire shells and inlet/outlet pipes on magnaflows are stainless, and on the dynomax I think the inlet/outlet might not be stainless...I can't remember.