Ok, i understand that on a stock 88 305 tpi it might cause a slight gain of maybe 3 hp.

However i was wondering if it would be worth putting a high flow cat in now that i have done the following

1/ the free mods
2/Good set of Headers
3/Hooker cat back system
4/Slp runners
5/Edelbrock tpi base intake.

Now as far as the current cat converter, all i know is that it is old. It does not get red so it is not clogged however that is not to say that is free flowing


So, any feedback is very much appreciated.

high flow cat....

sonds good but i would prefer to actually know if you feel a difference as in wow

my car with the old L69 305 in it went from a 15.9 to a 14.7 from just deleting the catalytic converter......when i posted this a lot of people thought i was lying....but i posted the time slip to show the truth.....and then i was told my car was a freak and that those gains are not usual.......here is the 14.7 timeslip again....

Your car is def not normal. You can't gain that time just by removing the cat. Everyone would know about it, and it would be the first upgrade everyone would make. Congrats on having a frankenmonster though!

How did you put headers and a cat-back on there while leaving the stock cat? Ugh, that must be a huge restriction there. Open that sucker up with a 3" outlet y-pipe, a 3" Magnaflow catalytic converter, and 3" cat-back exhaust pipe.

It is 3" and so is the cat back. I know i should have changed it from the begining. I guess that is the next step then

thanks,

Sam

No...

A high flow Pipe....

Best idea yet is the pipe....If you have visual inspection, gut it.

Ok so i guess an original cat will be just as good as the high flow? I mean +- 2 hp is not worth the extra cash.

thanks

Sam

How can I gut my cat?

I am sure they mean take a bar and smach all the internal out the other end or you can do that and then put a pipe staight through and weld it on both ends then put it on the car....

Is it a good idea to just gut my stock cat?

If your state has visual inspections for emission control then yes gut it. Some say to run a pipe through it but to me it wasn't worth the trouble. Theoretically it would flow better with the pipe through it. I removed the rear pipe from the cat and used a long drill bit and sucked the crap out with a shop vac or blow it out by starting the car. Get it ALL out. You could remove the cat and beat on it with a piece of rebar or something but my way is easier, I have done it both ways.
Bill

THANKS BILL!

Another good thing about using the long drill bit is you don't have to cut the air pump tube that dumps into the cat. Besides the factory squeezes the crap out of the front ypipe to cat connections to the point you have to heat with a torch and wiggle it off. Go the easy way with the bit, I had a bit left over when I built my house, the electrician or the alarm guys were using it and it looked like it would be handy some day so it got misplaced so to speak. ...lol

i also did the drill bit when i gutted mine and it made it REAL easy!! drilled the crap outta it and strated it up and reved it up.....hopefully you dont break any of the bolts! good luck!

I could possibly belive it though if the stock cat was plugged up or something

aren't the l69's already in the low 15 high 14 second range as is if the car is in good running shape and has a good driver?

it seems like most of what happened is you went from lg4 performance to l69 performance :P


also could be other factors like weather traction at the strip from one day to the next or maybe the driver just SUCKED on that first run

all the cars I own that came with a cat have had it removed. thank *** for no visual inspection here in caldwell, idaho. if I Was going to leave the cat on I would run a straight pipe through it myself due to the better flow that would be gained as such vs just the open chamber of the cat.

not good for the enviroment though but my mazda never was good for the envrioment anyway I don't think and having the stock thermal reactor and 3 cats on my little 1.3L was never good for performance so it had to go. guess I will be off to plant a tree now to help make up for my difference

A friend of mine has a '93 RX-7 twin turbo, fast as hell. When I ride with him , I fall into the thing it feels like my *** is 6 inches of the pavement and I am on a roller skate from hell. Damn thing pulls so hard it is scary, to me it always scary in a fast car if I am not driving, something about being in control I think. We gutted his cat and put on a cat back exhaust and upgraded his air intake all at once. I mean to tell ya' that car is wicked. Some guy from our work had a BMW of some type. We were working in the engine overhaul shop at TWA in KC before American bought us and as you can guess most guys there were gear heads. This guy with BMW which was his wife's car was telling us how all the bolt ons like cold air and aftermarket muffler and chip added all this hp. He was claiming 40 hp from the chip, we just looked at each other and smiled. My friend's RX-7 came from the factory with 250 hp and it weighs about 2200 lbs give or take. They went back and forth and soon a a case of beer was bet and after work
they started from rolling 60, stupid on the BMW guys part because the RX-7 turbos are well spooled at highway speeds.
My friend nailed his RX-7 by 100 we now longer could even see the BMW .
We had a few on his dumass that night. lol . I hate ricers but the RX-7 was a monster and there are tons of extra hp which can be
bolted on with an upgraded turbo and chip tuning. Much like our 20th Anniversary TA with the 3.8 turbo which is comparable in power to the RX-7 and OBVIOUSLY better looking.I keep telling my friend about them, he don't believe, someone have a 20th TA I could borrow to kick his ***....LOL

What was the MPH of each run? Comparing e/t isn't very useful. On my old formy, I could run low 14s, or low 12s at 119mph. Just depends on how I took off.

I'd be interested to see what MPH increase you got, if any. Thats more directly related to HP.

-- Joe

The top two are from when i just had the K&N air filter and the hooker cat-back.....top right was when my car had vapor lock issues because the stock cooling fan doesnt kick on til 220!!...but i soon fixed that .....


The bottom two were after i gutted the cat......bottom right is my 14.7 but u just cant read it.....but i do remember it being at 92mph......

picture doesn't work

sorry....hopefully it will work now

wow....u left the stock cat on there? How big was your stock pipe?

holy crap, +8 mph in the quarter!!!

I'd be willing to bet you had the clogged cat from hell.

looks to me like a traction issue in the first run...you got a full second faster on your 330 ft times......it's your story tell it like you want.......I'd have to see it.......doesn't matter much you now run better with more horse power.........

Well, sorry to change the subject a lil bit but, I ordered a new hiflow cat from Catco, or so they say. A few people from this site told me to drill out the stuff in it, so I did. Hiflow my @$$!!!! That friggin thing was like a behive! I tried to blow air using my mouth through a small piece, and I almost passed out. I can see how easy ot is to get a cat clogged!

Alright, I want to cut off my cat(s). Do I need to worry about any O2 sensors at all? If so, would a resistor work to bypass it?