i am getting a new dynomax exaust and a new cat, but i was wondering does the cat have to go from a smaller stock pipe into a bigger 2.5 inch or is the pipe that goes into the cat 2.5 allready?

 

I think"!THINK"! the dyno will bolt to the stock converter. BUT NOT POSITIVE. I made the mistake of putting on a high flow cat, and lost ALOT OF POWER. I am waiting untill this summer when I make another set of headers AND Y Pipe for my car before getting a universal replacement that is 2.5".

 

the thing is that i need a new cat, so i was wondering what size openings that i need. And what do you mean by you lost power what kind did you get? Has this happened to anyone else?

 

the thing is that i need a new cat, so i was wondering what size openings that i need. And what do you mean by you lost power what kind did you get? Has this happened to anyone else?


There might be some confusion, i am getting everything new from the cat back including the cat everything from the engine to the cat not including the cat is stock.

 

I have to get a new cat, mine is shot and i was wondering what size to get? and what do you mean you lost power? what kind do you have? Has this happened to anyone else?


I think there might be some confusion. I am getting everything new from the cat to the tail pipes includeing cat. everything from the engine to the cat, not including cat is going to stay stock.

The pipe coming from the back of the car into the cat is 2.5 inches but i wanted to know what size comes into the cat from the front?

Thanks!!

 

wow sorry tripple post????

 

Anything worth saying once.... well, that's still overboard!

Anyway, C_H_C lost some low end torque (that I still think should have been made up for in high end power - perhaps a better intake?)

'88 2.8, same size in as it is going out. Just look under the car, you should be able to notice any difference!

 

I lost more then just "low end"; I klsot the entire freggin ban! I used to be able to chirp THIRD!, noe I can hit 2nd hard and break it. and thats it!.
Top end, is negliably better, but I perfer low end thanks.

As for the intake system, 3" PVC, the actual manifold IS ported.

But to the question, go 2 1/2 universal replacemtn, NON HIGH PERFORMANCE.

 

what brand cat did you buy?

 

sorry, im just glad i live were i do!, small town in canada BC, no tests or anything, i dont use a cat, it is basically only illegal if a cop decides you have to much black smoke coming out the pipes lol. im sure if i ran a v8 i would get a cat for the environment and all, but right now even without a cat i could prob pass emissions in LA, my car runs really good n clean, about the pipe sizes, yea just look... you can tell the diff of 1/2 an inch and ask werever your ordering from what size you are getting or just tell em you need a cat to conect to 2 1/2" pipes

 

C_H_C - So you're saying after I install your headers and have a Y-pipe fabricated that I should still not use an performance aftermarket cat? And instead go with a generic "stock one" so to say? Thanks.

 

yes i think he is saying that, the preformance cats let air through faster, which means less back pressure, with a v6, you want back presure, also the stock, non high flow, are cleaner. Also as far as pipes go... i think it would be better, on a 2.8l engine, to use 1 1/2 or 2" pipes, the 2 1/2 and 3" ones are too big even for the unmoded 305.

 

I will put it this way. I still have stock manifolds on, and with the tock 'vert on I had MAD trq.

Now with same manifolds, and catco cat, I have NO trq. And I even have pretty $hitty tires that "can" loos traction in a heartbeat.