CYAL8R

hey guys
i already have a downpipe so i have no pre-cats, but im looking to lose the main cat now. can i just take it into a muffler shop and have them weld on a straight piece to replace the piece with the cat? or do i need a brand name piece? will this make a big difference in performance? thanks

Ryde _Or_Die

A muffler shop can do that for you. IF they will is another question. Some shops won't do it. It should give you a very noticeable gain.

baix2

good luck with the back fire

RX-7 GT

whats wrong with backfire? shouuunds scheewweeet

Rx_treme

yeah mine doesnt backfire anymore, except after i let off on fuel cut. i'm pissed.
~~~~~~~~~~~~~~~ 86 GXL ~~~~~~~~~~~~~~~~
~Series 4 J-Spec ~Haltech E6K ~Apexi N1 Dual
~Turbonetics T04b, Super V-Trim, P backside, .69 A/R
~2.5" Down Pipe ~2.5" Straight Pipe ~Bonez Intake
~3" TID ~AVC-R ~Perma Cool 16" E.Fan ~8mm Wires
~Blue silicon lines ~TB mod ~TB Polished ~No Emissions
~GReddy A/F w/ 4 wire o2 ~Whole Exhuast Thermowrapped
~Tokico Illumina 5 ways ~HKS Super Form Springs
~17" Konig J-specs ~245/45/17 Kuhmos ~T2 Tranny/Clutch
~Phoenix Gold Stereo ~Recaro Race Seats ~Debadged
~Tinted Windows ~New paint ~2700 lbs.
--------In the mail-----------
~GReddy FMIC ~Blitz Super Sound BOV
~Walbro Pump ~800cc Secondaries~ ~HKS POV
--------Up Next-----------
~Racing Beat Sways ~Strut Tower Bars
~Camber Plates ~Camber Links

snoopster76

isn't that what you mean just kiddin. what's the plan for this weekend? also, check out the six port question. is that the guy with the white one?

org post
yes you can, just need to find a shop that will. makes a big difference in performance too.

spinner26

I did it to my '86 GXL. The muffler shop told me that it was not emmisions legal and I told them I didn't care. That seemed to be good enough for them.

After it's done you will backfire more but it's not too bad. I get a louder exhaust note and some of it reverberates through the floor as the straight pipe runs down the middle of the car.

6-ports...Mine may or may have not worked before I got the straight pipe, they assuredly did not after the straight pipe. You can buy pre-made straight pipes with enough backpressure to blow them open or save the $$$ and do a web search to find the way to rig your ports up to the airpump (which is what I've done)

So, for the $50 it cost for the straight pipe and 15 minutes to rig up the 6-ports it's a pretty good mod with pros and cons.

Pro - Faster, louder, economical

Con - 6-port conundrum, stinky



--Mike

PraxRX7

I asked a muffler shop to replace mine with a straight pipe...they can do it, however i have decided just to buy a whole new exhaust system

CYAL8R66

what is this back pressure you talk about? well i might buy a Bonez pipe that replaces the downpipe and straight pipe...would this be worth the extra money? i want use of all 6 ports

CYAL8R66

whats the deal with the backfiring? im not sure i know what that is.....

Redwood

The "backpressure thing" that he's talking about applies to 86-88 n/a's (at least, I don't think it matters on 89-91, could be wrong). The 5th and 6th ports were opened by exhaust backpressure. If you replace something in the exhaust system, you could (in this case, will) lose the backpressure necessary to open the remaining ports and, thus, lose power. To remedy this, you can use a little tubing and some t-pipes to open the ports. <--There is a really good write-up about this on here that was posted a few days ago. Do a search for it.

The Bonez pipe seems like a good idea, if you want to spend the $$$. I imagine the only real advantage it would offer is a bit quieter. Other than that, the muffler shop method is the way to go.

Backfiring is (to the best of my knowledge) when a little unburned fuel passes through the exhaust system and then combusts when it contacts the air. Happens mainly on shifts and slowing in gear. Pretty cool actually, and this is the famed flame-throwing that 7's are famous for.

Ryde _Or_Die

I am interested in the way to make your 5th & 6th ports open. You use the air pump right? Where is the write up so I can see how hard it will be? Thanks.

t_mak@mail.plymouth.edu

Backfire doesnt always mean flames. I've been running with no cats for the past year. I get loud backfire, especially with new mufflers, but still no flames. Damnit. I get the backfire mostly when i back off at high RPM, bt sometimes in the low rpm after i hold it for a while

baix2

my car does that too...say u in 3rd gear and push it up to around redline (u problaby wanan do that on the freeway,3rd gear redline is about 80mph)...let off the throttle for about 3-4 secs...and then if i kinda like punch the gas pedal..it will constantly backfires...can backfire about 5-6 times in a row...and flames also...(i never actually seen the flame in person, but my friend saw it when he was behind me), and sometimes when the car backfires at night, from the mirror i can see some lights from the fire. and i think higher gear, higher load on engine, bigger flames

and RX-7 GT: there's nothing wrong with the backfire...i used to love it...that was kinda like the whole point of me getting straight pipe. backfires are fun..and this one time i actually felt the backfire on my back from my recaro spg...scary..and it gets kinda pointless after a while..it's cool to see it though
i haven't heard anyone saying that backfire is bad for the car, except if u r running extremely rich...

but anyway, good luck with the car

CYAL8R

well if i do get the straight pipes, how do i know if the 5th and 6th ports are opening or not?

Ryde _Or_Die

Thats my question CYAL8R, I know they open with the siliencers so I guess I will have to buy those.

Rx_treme

heres my write up of it.
http://www.geocities.com/rx_treme/6portactuation.jpg
any ?'s
Jason

MaxRX7

flamage is VERY

Ryde _Or_Die

Where does the exhaust fit in that pic? I mean where is the needle valve actually at on the exhaust? And where does the "cable tie" go? Thanks.

Rx_treme

thats the beauty of it, it has nothing to do with the exhuast. you just use the pressure from the air pump.this way you dont need the pipe running from your air pump to the exhuast, you can just run a single pipe. the reason you zip tie that cable is so it doesnt swing around and catch on fire on your exhuast manifold.
Jason

oh by the way for anyone out there i have one for sale, 2.5" pipe from exh. manifold to the cat-back. $75+shipping

Ryde _Or_Die

Well how hard is it to do all that? Where do you start, the back of the air pump? Do you have any pics on the car at all? Thanks.

Node

iTrader: (1)

page is not available

Prowla RX7

what page?

CYAL8R

yeah that page doesnt work....

RXTASY1

Go here.
Also, if you don't need your main cat anymore, just gut it!


http://home.rmci.net/panther/6PortSolution.htm