Maintenance for muffler (?)

[GEN 3 SHO FAN]

Thanks Stephen. I ask that because from what I saw from dyno sheets (I printed some from V8SHO), it seems that deleting it, with some others mods sadly, seem to add around 5 hp...

If it really affect the performance, I think I kept the shell of the third cat which I could just replace it...

 

[RonPorter]

It wasn't a dyno run, which would be difficult to show midrange on an ATX.

And remember, dyno shops were not on every street corner like today.

IIRC, both Scottie Waters and Randy Smith reinstalled their 3rd cats, and discovered the midrange that they had lost.

Midrange torque is less than on the V6 ATX, and is sensitive to mods. Part of the reason I sold my 99, as it frustrated the **** out of me at the two road courses I ran it on. IMO, the best performance mod for a Gen 3 would be to swap in the 6-speed EcoBoost ATX.

 

[RonPorter]

Thanks Stephen. I ask that because from what I saw from dyno sheets (I printed some from V8SHO), it seems that deleting it, with some others mods sadly, seem to add around 5 hp...

If it really affect the performance, I think I kept the shell of the third cat which I could just replace it...

It may very well add 5 dyno hp, but that's useless. 5 hp at the top end isn't something anybody will feel. To get that supposed 5 hp, you give up midrange torque, which is the one thing that the V8 can't afford to lose.

It's just like adding big cams. Sure, they will show big top-end hp gains, but old ladies with walkers would beat you across an intersection.

 

[luigisho]

God I'm getting old-- agreeing with Ron more often! More power is fine but usually a trade off and you have to get the power where you want to use it. Salt flats run get all the high end you can. Driving in town and short highway runs, get it low and/or mid so you can put your car where you want it merging, changing lanes, and passing.

 

[GEN 3 SHO FAN]

Humm... Ok then, and if I would replace a cat there, there is alternative to the no more available 3th cat ? It's a summer daily driver, not an auto-cross thing. I try (most of the time) to manage her, it's an old lady now. I'm not searching to create a monster with it and **** out the trans. If I still have the shell, could it be repaired or it will be simplier to replace by another new with 2.25 inches openings ??

 

[rubydist]

buy another with the correct inlet and outlet sizes.

 

[stephen newberg]

I agree, it would be simplest to just pick up a cat of about the same size with the same in and out sizes. If you get desperate, let me know. I think I have a spare brand new one in my parts collection that is even the correct replacement part number that I picked up when I redid the exhaust system some time ago but ended up not needing as the old one was still good.

smn