1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Hi-flow cat or straight pipe?

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Old 09-18-01, 07:16 PM
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Lightbulb Hi-flow cat or straight pipe?

I have this rattling coming from my cat, i think its old and it needs to be replaced. I am thinking of getting a custom straight pipe, or a high flow cat, what do you guys suggest?

btw once i do that im sellin this rx7, i am planning on purchasing a rx2 or tII, im still in decision. If anyone might be interested ill get pics up, its a 1985 rx7, custom silver paint job, CLEAN, except for some chips in the paint. It runs smooth, the same brand oil filters throughout the life of the car, i got all recipts etc etc..
Old 09-19-01, 03:35 AM
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I opted to toss on a High flow cat, I picked it up from rx7.com, it replaces all 3 cats w/ a pre-silencer and a high flow cat. It keeps the car emissions legal, keep's my 6-ports working, and muffles the exhaust a lot. (I have a huge hole in the pipe infront of the muffler, and it's still quite bearable) You also keep a bit of low-end torque over a straight pipe.

Of course, with a straight pipe you get flames.

heh. rock! fire!
Old 09-19-01, 08:35 AM
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Are you sure the rattle isn’t a heat shield on the exhaust?

If your going to fix it you may want to see what the regulations are in Cali would imagine you’d need a Cat.

If you plan to get rid of it why don’t you save you pennies and just sell the car.
Old 09-19-01, 01:54 PM
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yeah.

Yeah im probably going to just sell it as is, i mean its a nice clean car that runs fine, just some cosmetics.
Old 09-20-01, 07:43 PM
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Jack up the car and see if it ain't the heat sheilds.
If you are going to sell it anyways and are worried that the buyer will frown on the noise. Yank off the cats and shake'm to see if the material has broken loose. The first two will likely be hollow by now anyways. If it is banging around, then take a long rod and hollow the rest of it out. No more worries.

Just the the next owner deal with the cats and smog.

A replacement cat will most likely cost less than the cat replacement pipe. www.discountconverter.com will sell you a stock bolt on replacement for around $100.
Old 09-20-01, 07:53 PM
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i had the same rattle under the car, especially when i shifted ...it turned out to be loose heat shield (as some of you are saying also)........fyi.................................. ..........................
Old 09-20-01, 09:46 PM
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yes.

Im no so worried about that sound, its my driveshaft that i need replaced. Theres no problem with the performance of it, but it makes alot of noise. I was going to just repace the U joints, but i dfound out in the 85 year they are welded onto the driveshaft. So.....i need to replace the WHOLE driveshaft in oder to fix the niose. Totalling up to 400 dollars, **** that.
Old 09-21-01, 12:46 AM
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Mazdatrix has a driveshaft that will fit, and has replaceable ujoints.

www.mazdatrix.com

2691-701.........DRIVESHAFT............83 ALL + 84-85 MAN....$ 242.00

--matt
Old 09-21-01, 01:23 PM
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ok

Yeah its less money, but im still pretty annoyed that i gotta pay 300-400 dollars for this. This is my final project, then everything will be running great.
Old 09-21-01, 10:23 PM
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just be glad that your final project isn't alot of bodywork like mine is. I'm expecting to spend a whole lot more than 400$ on that...



--matt
Old 09-21-01, 10:52 PM
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Yup, Bodywork's a bitch!

This apartment caught fire and my car was close enough to feel the heat.

Melted most of the rubber on the front of the car as well as made the hood/fender paint not stick to good anymore. Left it parked while I searched for blinkers and stuff to get it fixed, some kid hit the car with his head and helmet when he fell off his bike... One thing led to another now I'm at ~$3300 in "looks" repairs. That car sure is lucky I love her or else! Been driving my Miata around but I sure do miss 3rd gear at 70+mph. Wish I had a garage/house to pull the car in and do the main stuff myself. Oh well.
Old 09-22-01, 02:02 AM
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hmmm...

Im actually thinking about getting a driveshaft from a dismantlers.....
I know, it could be fucked, but i might get lucky, its worth a try i guess. Hopefully i can find a "good" one for a decent price, then get some crazy *** mechanic firends of mine to help me install. If u havent noticed Labor $ is a bitch these days.

Yeah so, ill be all fixed up once thats done. Then ill sell her, pix up soon.

btw im sellin cause im gonna buy a tII or a Rx-3 soon.
Old 09-22-01, 04:29 AM
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installing a driveshaft is easy. unbolt the shaft from the diff, let it angle down and slide aft out of the tranny (prepare to loose tranny fluid ) installation is opposite of removal.

ok, so it's an over-simplified explanation, but that's basically all you have to do.
so F labor, get some jackstands and do it yourself!

--matt
Old 09-22-01, 01:49 PM
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Thumbs up :)

Word.
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