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Thread: High Flow Cats - M400

  1. #1
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    Default High Flow Cats - M400

    For those that have done this I would like to hear your impressions.
    I have heard some going with no cats, but I'm not sure if it would pass TX Inspection like that so I thought I would be safe to atleast do the high flow ones if it is worth while.
    Better throttle response? More power? Better sound?
    Thanks

  2. #2

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    Quote Originally Posted by GHOSTRIDER
    For those that have done this I would like to hear your impressions.
    I have heard some going with no cats, but I'm not sure if it would pass TX Inspection like that so I thought I would be safe to atleast do the high flow ones if it is worth while.
    Better throttle response? More power? Better sound?
    Thanks
    The current cats are high flow. However, Carsound makes some high flow cats as well if you want to try another manufacturer. If you could get better flow, your advantages would be some extra HP, and better throttle response.

  3. #3

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    Quote Originally Posted by S.J.Morgan
    The current cats are high flow. However, Carsound makes some high flow cats as well if you want to try another manufacturer. If you could get better flow, your advantages would be some extra HP, and better throttle response.
    As SJ said, the stock are already metal matrix, which are some of the most efficient on the market. They're much better than the ceramic monolithic cats you find in most OEM vehicles.

    For the aftermarket, Carsound does seem to make the best, flowing even better than the Random Technology ones (another popular choice), yet costing 1/2 as much. Carsound's 59920 Series is the one you'd want to get. It's their top of the line, highest flowing series. If you decide to stay with the stock 2.5" exhaust tubing, which would be the easiest, you'd want to go with the Carsound 59926.

    http://www.magnaflow.com/richard/NEW...LIC%20CATS.pdf

    My friend just picked up the 3" one and it costed $99 shipped from here:

    http://www.hottexhaust.com/search_re...2&txtCatName=2

    You may want to call them and ask if they have the 59926 in stock.
    RacePrecision GotApex

    "Be ashamed to die until you have won some victory for humanity." ~ Horace Mann

  4. #4

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    The UK boys who have dyno'd with and without Noble cats say it has marginal effect on HP but does reduce noise quite a lot.
    Regards
    Paul C

  5. #5

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    Quote Originally Posted by Paul Cundy
    The UK boys who have dyno'd with and without Noble cats say it has marginal effect on HP but does reduce noise quite a lot.
    Regards
    Paul C
    About 11hp and 12 lb/ft of torque gain on a 3R was I believe what they said.

    http://www.pistonheads.com/gassing/t...6&t=239058&h=0

    I think there was a second thread too that said about 10hp, but I'm not positive. My memory is getting pretty bad.

    M400 should be a few hp up from there.
    RacePrecision GotApex

    "Be ashamed to die until you have won some victory for humanity." ~ Horace Mann

  6. #6

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    Quote Originally Posted by OnyxM400
    About 11hp and 12 lb/ft of torque gain on a 3R was I believe what they said.

    http://www.pistonheads.com/gassing/t...6&t=239058&h=0

    I think there was a second thread too that said about 10hp, but I'm not positive. My memory is getting pretty bad.

    M400 should be a few hp up from there.

    I would guess a max of 10 HP, but the reality is actually half of that, at best, if the car is in proper tune. Sometimes, there is a loss of bottom end torque. Tuning is getting pretty sophisticated, and cats don't cost much HP at all.

    The main advantage to removing them is the reduction of heat in the engine compartment, and the weight reduction. Otherwise, I would leave them alone. Nothing like lots of HP and clean air.

  7. #7

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    Quote Originally Posted by S.J.Morgan
    I would guess a max of 10 HP, but the reality is actually half of that, at best, if the car is in proper tune. Sometimes, there is a loss of bottom end torque. Tuning is getting pretty sophisticated, and cats don't cost much HP at all.

    The main advantage to removing them is the reduction of heat in the engine compartment, and the weight reduction. Otherwise, I would leave them alone. Nothing like lots of HP and clean air.
    SJ I agree. I think Trevor Jasper from Rousch says they loose as little as a couple of Hp. Certainly not as much as 10. The loss with them in really is insignificant. One problem with them is that the early ones tended to dissintegrate and then when they blocked the exhaust there was a severe Hp penalty! Maybe thats where the myth comes from.
    Regards
    Paul C

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    I have a exhaust which has bolt in/out CATs. Currently it's without the CATs, the logic being that there's less to go wrong when they're not fitted plus more heat goes out of the pipes rather than into the engine bay.
    --
    Richard

  9. #9

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    Quote Originally Posted by chillidog
    I have a exhaust which has bolt in/out CATs. Currently it's without the CATs, the logic being that there's less to go wrong when they're not fitted plus more heat goes out of the pipes rather than into the engine bay.
    --
    Richard
    I ran cats on my race car for 14 years. The first set lasted about 8 years when my modification program required high flow cats. The OEM cats never had a problem with over 2000 miles of testing at Willow Springs, and the Carsound high flow cats didn't have any problems over the next 3000 miles of high speed testing. Add to that over 120,000 miles total daily driving (same vehicle) and I reached the conclusion that cats are pretty reliable provided that there are no great errors in the fuel/air ratio.

  10. Default

    Quote Originally Posted by S.J.Morgan
    I ran cats on my race car for 14 years.
    and had they failed on you during a race you'd have been better with them not fitted in the first place.
    --
    Richard

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