Community Forums

Mitchyb · 07-08-2013, 09:28 PM

Hey guys, wanted some opinions from some fellow vintage owners, my 1990 460 with 60k miles on it seems to be a little under powered. I have changed plugs and wires etc and don't want to or will my wife let me install a Banks power pack so my plan is to remove the Cat. Now we have no smog testing here so I don't have to worry about that. It's a bit of fab work to go from 2 pipes to one but still only 100 bucks to chop it out. Has anybody done this and what kind of results were achieved? Thanks!!!

jmckinley · 07-09-2013, 05:21 AM

Once upon a time, I did this on a Bronco by unbolting the converter and punching out the insides with a broomstick. Then I reinstalled it. Cost = Zero.

Phobos · 07-09-2013, 04:46 PM

Quote:

Originally Posted by jmckinley

Once upon a time, I did this on a Bronco by unbolting the converter and punching out the insides with a broomstick. Then I reinstalled it. Cost = Zero.

The only problem with doing that is sometimes the unburned exhaust gases build up in CAT and cause backfires when decelerating.
The end result is usually nothing but annoying noise, but sometimes, if it's close enough, it will blow the guts out of the muffler.

Bilito · 07-09-2013, 06:53 PM

Quote:

Originally Posted by Phobos

The only problem with doing that is sometimes the unburned exhaust gases build up in CAT and cause backfires when decelerating.
The end result is usually nothing but annoying noise, but sometimes, if it's close enough, it will blow the guts out of the muffler.

That reminds me of something we did as teens in the 50's, got a pair of smitty steel paks (Straight thru's), poured some oil in each one, swirled it all around and installed them and ran the hell out of the engine, in about a half hour the oil burned out the steel wool in there and the sound was WOW, and the car seemed to have more power. Ah the good ol days

stink · 07-09-2013, 07:02 PM

I do not know about emissions laws in Canada but in California you can get a $20000 fine for removing or gutting a cat. Here we can install some high flow cats that have no back pressure and will not effect emmissions. If you can remove, a strait pipe in place of cat will give good airflow. Your muffler, if stock has more back pressure than your cat.

Phobos · 07-10-2013, 07:43 PM

I might also add that I highly recommend against removing emission control devices from any type of automobile.
They don't restrict performance as much as everyone is lead to believe and I personally like clean air to breathe. It makes living on this planet a whole lot easier.

jamesrxx951 · 07-10-2013, 07:58 PM

Many versions of the 460 did not even have a catalytic converter. I would also be surprised if a 23 year old coach would still be required to meet any emissions test any more. Maybe California but if some did not have the converter then.........

I think the biggest improvement would be lower exhaust temps. The exhaust is so restrictive on the 460. If I kept my 93 motorhome, I would going to remove the smog pump and the exhaust and go with a larger pipe. My biggest desire was to keep the exhaust cooler. From what I have read here, a better exhaust really helps with that haul up a large grade.

stink · 07-12-2013, 02:37 PM

Jamesrxx951 has a good suggestion to upgrade the entire exhaust for added performance. I would use the stock manifolds and 2 1/2 pipe, some high flow cats and three chamber flowmasters. I would not go with any larger pipe no mater what the exhaust shop wants as bigger is not better with exhaust pipe, smaller pipe pulls more exhaust from engine while larger pipe the exhaust gets stagnet and causes higher back pressure. NASCAR uses 2 1/2 pipe!

Adaycj · 07-12-2013, 03:18 PM

Quote:

Originally Posted by stink

I do not know about emissions laws in Canada but in California you can get a $20000 fine for removing or gutting a cat. Here we can install some high flow cats that have no back pressure and will not effect emmissions. If you can remove, a strait pipe in place of cat will give good airflow. Your muffler, if stock has more back pressure than your cat.

Not that you would get caught, but there is a federal law with steep fines too. On my 1992 454 I added a modern cat and ditched the pellet type cat. I got a noticeable performace increase at higher RPM, and it was really cheap for an old school 3 inch OBDI (not a 3 way catalyst). I got mine, all stainless, from the local auto parts store for $30. And by all accounts I polluted less with the new cat.

cb1000rider · 07-13-2013, 10:20 AM

I'd do a set of (non-Banks-$$$) long tubes. I've punched out converters on early 90s mustangs (302ci) and managed to create a car that would stink at idle with the windows down, tested 10X higher in unburnt hydrocarbons, and achieved no noticeable HP difference. These cars were rated at 205 or 225hp (depending on which year you believe).

Long tube headers will deliver a little more HP, which is what you're after...

The latest stuff that I worked on was building EFI systems for turbo motors. In these, I run a $75 high-flow catalytic converter. You can buy them at Jegs/Summit. Cheap, work great, legal.

Mitchyb · 07-16-2013, 08:16 PM

Well I removed the Cat and the power does seem a little better, it's a but louder under load but not abnoxious, I was able to accelerate up hill quite well and held 40mph in second gear with ease I think right now it was a good decision but ill keep you posted