racerfoo

Is there any reason (besides being insanely loud) that I shouldnt remove my midipipe/catback and run an open downpipe for a run or two at the drag strip? My wastegate is heavily ported (bigger flapper than stock, bigger hole).

Snook

iTrader: (12)

if you can control the boost I don't see why not. I think you are on the stock ecu though arent you? You may be pushing the limits of the stock map doing that even at 10psi.

EpitrochoidMan

If your wastegate is heavily ported and you don't have smog to worry about, and don't mind the noise (or the pretty smell) there is no reason not to run an open exhaust.

1QWIK7

iTrader: (33)

^^unless the track he runs at requires muffled vehicles unless it can make a pass for a certain time..

adam c

iTrader: (2)

Since our cars shoot flames at times, an open downpipe will shoot flames under your car. This will create a significant fire hazard.

Bad idea.

EpitrochoidMan

^^true, I just realized he meant he was ONLY going to run a DP

1234rotor

iTrader: (1)

A two second flame is not going to hurt anything. Unless you have something under the car that shouldn't be there stock. the fuel lines are on the driverside of the car. The stock ecu would be my only concern.

It isn't any louder than some hot rods with Flowmasters that i have heard. I ran mine for two days with just the downpipe. Everything else was bone stock. It's not real loud because the turbo and pre cat muffles it a good bit. Since then I have eliminated the pre cat. Yours may be loud if you don't have the pre-cat though. Most dragstrips don't have a muffler law, unless it has changed since i used to drag in the late 90's.

1QWIK7

iTrader: (33)

i kinda agree with the above, i mean maybe 1 or 2 passes wont hurt but theres still a risk.. all the top pros with their starlets running open dp shoot flames during the 2 step..kinda scary when you see a wide row of fire rather than some quick flames..

racerfoo

thanks....and im not on the stock ECU anymore. I'm shooting for 11s on stock boost, if I cant shave the extra tenth or two off w/ a better launch, then i'll unbolt the exhaust. If that doesnt work, screw it....boost gets turned up!

Snook

iTrader: (12)

You'll have to get the midpipe out of the way not just unbolt it if you want good flow and I'm not sure if you can just remove it especially launching like that you don't want your catback to fly off...

also it's ok to have flames under the car for a couple seconds at a time. I use a cutout at the track and I've been told it shoots lots of flames but everything is fine. Mine points toward the ground though.

what ecu are you on now?

user 9348703

I assume you will be runnng a small pipe to shoot the flames towards the ground right? That would be smart.......

If the flames really bother you, just extend the pipe and make them exit towards the side of the car and back.

Personally mine shoots the flames at the ground if there is any..

jeremyb

I suggest to just buy a cutout. An efficient and very nicely designed one can be found here. www.quicktimeperformance.com . just keep your stock piping after tour downpipe on so when you pass the cops they dont know your running like a crazy guy. cause ull have it closed. sounds just like stock =) but when ur about to run a v8... and u open your cut-out, they hear a supposedly stock rx7 turn into a growling (one of them) vehicle. And its just like running open downpipe when its open. The priceless moment is seeing the face of the ppl at the lineup when they hear your car suddenly raise its decibels at idle by 50.

marix1521

i ran mine with the cat cut completely out for 2 days... it sounded like ***, smelled like ***, and got hot as hell. as long as you can put up with it, i dont see why not.... my boost was fine. i'm running my car bone stock right now.....

bigmack000

i was thikning even with my 3inch strigth pipe. the pass side of hte car got WARM!. now think of just stoping, the pipe rigth under the pass seat. you cabin is goin ot heat up like oven.
just take the cats off and run a 3inch pipe to the back lol
joel

Snook

iTrader: (12)

umm he already has a full exhaust
simple question but we are getting many retarded answers here

racer you know more than the people here, you're better off just going with what you think is best

bigmack000

my post was more toward if he kept it off for good. i ran with just my downpipe for 2days on the street and i would never do that again. got hot and was ear bleeding loud. for a day at ther track dont see harm in it.

user 9348703

I miss-read this. OK my question is what is the point???

I thought we were just talking about an open air wastegate.

EKTwin93

I've run with my DP and MP only, and it was insanely loud, which was kind of satisfying, but I started getting worried about having my exhaust exiting right before my fuel tank. But the turbos did spool very easy, and loud, compared with having my catback on. I've got everything back together now, but I'm think about getting a custom pipe made to run from the MP out the back just for peace of mind, and my Greddy power extreme catback is just too quiet.

racerfoo

I planned on a cutout, but the last track event is friday and I wont have time to get it in and put on. Its only going to be unbolted for the evening at the track. Midpipe and catback will be removed....save some weight too

Surge, I'm running the PFS ecu now and pretty much have left it alone except for adding a little bit of fuel in and pulling a little timing to keep it safe. I know its still on 10lbs but its flowing a TON more than stock. If it doesnt rain this Friday hopefully I'll have an 11 second timeslip to show people who were wondering "whats the point".

adam c

iTrader: (2)

Be sure to take a fire extinguisher, just in case

racerfoo

C'mon I drive an RX-7......I never leave home without it