My 1986 WS6 TA has the code F TPI engine. The car is 99% original with 30K actual miles on it. The car looks 100% stock, and runs normally. The car also looks like no one has ever touched it, espically the exhaust system. The car mostly rides around in a trailer to shows and car events. We have owned the car since 2006, and have put 4200 miles on it in eight years. A few days ago the mechanic who did work on the car for the original owner, who is now deceased, told me that the Cat had been gutted when the car was about three years old. We live in NC, where the inspection of vehicles built before 1996 is all visual. It does not matter to the inspectors if the emissions work or not, only that all of the parts are there. I have read that a gutted cat will mess up the exhaust flow, trapping gasses in the Cat, and will cause issues for the tunning. I have no way to test the thing unless I take it apart, and don't like to take things apart unless they are broken. If the Cat needs to be replaced, I will need to find one that is an OE style, as the car shows as a stock original. The judges will count off for an aftermarket cat.Just for kicks and giggles, a couple of years back while attending a show in Atlanta, we took the car to an inspection station that belongs to a friend. The car was borderline, but barely passed, however due to the age of the car he could not determine that the car was altered or not. He said that it could be caused by it being a mostly original old car. Any thoughts? Thanks, Charles

 

So the post is long... Sorry.

My main question is if the Cat was gutted, will it damage the engine to drive it like that?

 

Has anyone installed a direct fit Magnaflow "high flow" converter? It is a 49 state legal and EPA compliant part. Will a high flow unit such as this cause any issues with the fuel mixture on the TPI?

 

JMO, a gutted cat will not hurt your engine. see what a few others say, but i vote no.

 

Thanks Joe, That is the same as what I am thinking. The turbulant air flow caused by the empty can can't cause any more back pressure then the engine having to force the exhaust through the "brick" inside of an intact cat. If the car had another sensor past the cat, it would be getting a faulty signal, but since the o2 sensor is on the left side exhaust manifold, it should not make much difference in engine tuning. It turns out that we are going to get to see inside of the thing after all. The fuel tank has to be removed this winter to fix a crack in the seal on the filler neck. The factory service manual says to disconnect the exhaust system at the flange, and let it sit on top of the rear axle which will have the shocks disconnected to allow room to R&R the tank. If the cat has been gutted, I will probably install a Magnaflow high flow unit as a replacement.

 

You'll be fine if it's gutted. You'd be better off if a straight pipe was in the cat instead of it just being a gutted shell. Either way you're fine.