nrichlen

Hi. Quick question. I have a single mod on my car: a Racing Beat dual tip catback. Numerous sites have said that the pre-cat can fail after awhile (my car has 110k miles) and destroy the catalytic converter. I have access to a shop next weekend and I decided now is a good time to install a downpipe. Am I in danger of hurting anything if I install the downpipe along with my catback? EVERYTHING else on this car is stock.

Thanks for your input.

Oliv

Hi, you should go through the search, I'm sure a lot of threads speak about this.

To my opinion, only good things can come out of this mod. Go on. You'll make your car more reliable and make the temperature in the engine bay go down! And you'll gain extra power!!

But leave the main cat on!

I'd suggest you to replace the OEM air filter by a performance air filter.

MDoe8

downpipe can only help you. Ive got one for sale if you're interested!

-Mike

RaPtOr-T

You wont be endangering anything, with the stock cat you wont be getting any boost creep. Also its not so much the CAT you should be worried about, its your engine! The pre-cat loves to clog and keep excessive heat in the engine bay. Downpipe is a must for every FD.

Mahjik

iTrader: (1)

https://www.rx7club.com/3rd-gen-archives-73/stock-ecu-10-psi-myth-308996/

prescription 7

iTrader: (5)

i love how the vet members here always have a thread as an answer to noob q. ....do u guys have them all memorized or what?

adam c

iTrader: (2)

A DP is a good mod. Combined with a catback, your boost will increase. Best to keep boost below 11 psi with stock ecu, and those mods.

Speed of light

iTrader: (8)

Downpipe was the first mod I ever made. I, too, was concerned about my high mileage precat (120+ k miles). As it turned out, the precat was fine, but I took it out anyway. Removing it made more of a difference than I expected--it really seemed to wake things up above 4500RPM. Will work fine with the catback. And it should still pass smog as well.

level7

iTrader: (3)

As a matter of fact we do. You read the same book over and over for 7 years you start to quote it like a priest quotes the bible.

"Thy new FD owner shall always inspect and replace the pre-cat, with an aftermarket downpipe, even if stock, or highly modified....."

Pre-cat 3:12

dgeesaman

iTrader: (7)

Isn't that from the Book of Armaments?

Anyhow, running a downpipe and cat-back is very common with everything else as stock, but like Adam mentioned, your boost may rise some. The key thing you need to watch is your boost levels, so you should also have a boost gauge added too. If your boost goes over 11psi (10psi is stock) then you should do something to get it down to 10 again. Usually though the dp and cb don't have quite that much effect, the 3rd flow mod is where boost tends to get a little wild.

lisaRX7infini

control the boost levels with a boost controller? apexi avcr?

nrichlen

People have said that a boost controller is a good option. Thanks everyone for your reply.

JConn2299

It's interesting to see that two owners report going over 100,000 miles with no apparant problems from the precat. It's almost become a matter of FD religion that the precat has to be replaced before 50,000 miles to avoid catastrophe. But as we can see, that is not always the case.

Like most people, I suppose, I became became alarmed by and paid the most attention to posts by owners who reported premature failures of the engine and its associated systems. Now, as the years have gone by, I'm paying equal attention to those who have high mileage engines with few or no problems. There's a lot to be learned there too.

AzEKnightz

iTrader: (24)

My pre-cat just failed and caused my car to run with NO POWER, so change the pre-cat with a downpipe is a good upgrade i suppose.

adam c

iTrader: (2)

I think most replace the precat to increase flow, and cool the engine bay. Failure is not a primary reason to replace
.

InsaneGideon

YMMV. Seriously, you're milage may only vary more than two or three more miles if you don't watch your boost.

I installed a CB and DP and went for a test ride. I saw the boost gauge fly past 13psi before the transition and let off throttle immediately. Funny thing is, the car often hit 11.5psi when completely stock. Maybe it's a '95 thing.

I parked the car and didn't drive it again until i got a boost controller on there.

White94RX

You have to have a boost gauge if you don't already!!! Just keep an eye on it, watching for boost creeping over about 10-11 psi. 10 psi is stock. Not sure if DP and CB will cause any boost creep or not.