1978 308GTS Hyper-Flow Catatylitc Question

It's actually cars that are 1975 and older that are exempt. 1976's still have to SMOG. Water under the bridge, though, as it makes no difference to your situation.

I am doing the same thing as you with my '79 308GT4. I don't have Hyper-Flows on my Ferrari, but I run a comparable brand (Random Technology) hi-flow cat on my '96 Corvette. Same deal -- i.e., 5% difference from straight pipes. They flow very, very well, and I just passed SMOG with them last week.

The reason I run straight pipes throughout the year on the Ferrari, and then swap in cats for testing, isn't for performance. It's to prevent the $450 replacement cats from being burned up by the car, thus requiring me to replace them bi-annually. I think you'll find the same thing would happen if you put in the pricey hyper-flows...the car will pass SMOG fine, it will run as if you've got pipes on it, and in 2 years it will fail SMOG miserably. When you pull the cats, you'll see that they're hollow.

IMO, just keep on doing what you're doing.

Best regards,
Aaron

 

I just swapped to a Hyperflow from test pipes and I can't tell any difference except now I no longer have that strong exhaust smell. I am very happy. (308 QV)

 

Tommy are you willing to sell your test pipe? And wil it work on my 84 QV ?

 

Sure. Mine is an 84 too. I had Stebro make it. I'll go $100 plus actual shipping if you really want it. PM me if you are serious.

 

Is there any historical basis for this or speculative?
My 78 had 29K+ miles on it with the original cats (based on build date on the cans) and they looked great when I peeked inside. I know cars have melted cats, but how many owners ignored Slow Down lights? Is there some reason to be suspect that there's a mode of failure on these cats that isn't due to high cat temps?

Dubious Don

 

At least for my car, there is historical basis - not speculation. The previous owner of my car had it for ~7 months. When he purchased the car, he SMOG'd it and it passed. When it came time for transfer of ownership, he had a very difficult time getting it to pass SMOG again. Ignition was tweaked, carbs tuned, plugs changed, etc., etc., but no pass.

The shop pulled the exhuast, and the cats (that were fine 7 months prior) were completely hollow. New ones were ordered, installed, and the car passed just fine. It was suggested to me by the mechanic that I might want to swap back to avoid the same ordeal (i.e., ordering new cats) in 2 years.

 

I would be interested in buying a set (new or used) Hyperflow Stainless Test Pipes or Stainless Hyperflow cats. Jim <[email protected]>

 

First place to go is Daniel Pass at FChat sponsor www.RicambiAmerica.com -- that's where I got mine at a good price with great service.

 

Very quick to answer emailed questions
Fast shipping and no charge for shipping on Hyper-Flows

Andrew

 

So... does anyone have a used set of stainless steel cats or test pipes they can sell me for my '78 carbed 308 GTS???? Jim <[email protected]>