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I noticed that on my 1989 GTA, recently bought (Italy), they removed the double-cats. Have a look at the picture below.
I would like to ask you whether I'm correct, that is, they actually removed the cats, or if I'm missing something.
Again, is it safe to assume that in this way I gained something like 10hp?
Emissions equipment is going to depend on the original country of destination.
(A Middle East destination car would tend to have less emissions control equipment than a car for 50-state U.S. use. And Canada and U.S. cars in the early 80s could have no-ECM carburetor, and ECM controlled carburetor respectively, for example.)
You can determine original equipment by the RPO codes. A GM dealer might be able to look up the RPOs by VIN.
Yes that is about where they would have been, if they had been there; a little to the rear, actually.
No you're not 10HP ahead. The cats that were used on cars like these have very little restriction. I doubt you could measure the with/without difference on a dyno. I'm pretty sure the normal variation from one run to another would be greater than the with/without change. It's even possible that a car with cats might have MORE HP, with all else equal.
That's an .... interesting .... way to support a car. Glad it was you taking that pic, not me.
ok but stock the GTA came with at least one cat, maybe two in 1989, right?
I can't believe removing it doesn't give me any hp
Originally Posted by sofakingdom
That's an .... interesting .... way to support a car. Glad it was you taking that pic, not me.
HAhahaha !!
Yeah, they used the wood arm because they were not sure about how to lift the car. But when we put the two supports in the middle, it was pretty safe
stock the GTA came with at least one cat, maybe two in 1989, right?
In the US, yes. As stated above, export versions are not always the same though, and none of us here knows for sure how cars that were sent to Italy were equipped. So, maybe yes, maybe no.
I can't believe removing it doesn't give me any hp
Sure. And at one time people couldn't believe the Earth is round. Everybody knows it's flat!
Why can you not "believe" this?
Your failure to "believe" something that's a fact, doesn't change the fact.
In the US, yes. As stated above, export versions are not always the same though, and none of us here knows for sure how cars that were sent to Italy were equipped. So, maybe yes, maybe no.
Well, actualy this car was imported from USA to England, then Italy. Im sure it has the cats.
Why can you not "believe" this?
Your failure to "believe" something that's a fact, doesn't change the fact.
It's a way of saying It's like "I know it's likely to be true, but it's hard for me to believe".
I reasoned this way: if splitting one cat to two cats (like they did in 1989) gave 10hp, then I gotta think that a single cat somehow restrict the engine power by obstructing the gas. Two cats provide less resistance, then more hp. Now, it's reasonable to think that removing the cat through and through should reduce even more the gas resistance, facilitating the engine.
This could be wrong, but it's through and through reasonable.
Depends when it was imported.Europe believe it or not has less strict rules about CO2 .Basically US in the 80s had the rules we got in early 2000 so if the car was imported in the 80s or early 90s it didnt need a cat. ...heck it even uses less fuel and one less part to change
talking about cliches and myths like how "advanced" european cars are
btw Euro 1 ....and so to Euro 6 is also bs because a E1 car can produce less CO2/km than a Euro 6 Lamborghini made in 2015...but hey don't tell the idiots in the EU parlament they are too busy taxing the air in the engines and talking about electric cars like everyone who lives at 10th floor in a apartment block can throw a cord out the window and charge their Tesla.
Last edited by FirebirdUSX; May 12, 2015 at 07:20 AM.
Below is a diagram for a 1989 Firebird Trans Am GTA with 350 cu. in. L98 VIN 8 equipped with the dual cat system (RPO N10).
Source: my 1982-92 Pontiac F-Body Parts & Illustation catalog.
GM probably sold the car in regions that didn't require cats.. so even if it left the factory with cats and got exported to a region that didn't require them, it's just a simple matter of going to GM and getting a Y pipe without cats.. i'm sure a little research could find a GM part number for the pipe.. or maybe it was an "off road only" "test pipe" that someone used to sell for race cars and what not.. i know i can get one of those for my 84 Regal T Type from a few different sources...
!!
