A friend of mine will be making a midpipe with a dumptube for me very soon, and I was wondering how many people would be interested in buying one. For those of you that dont know, a dumptube is a bent piece of piping that would send exhaust out before running thru the rest of the exhaust. Its loud and its great for the track. They will be priced around $180-$200 USD. as for specs. of it, I am unsure, but i will know soon. He specializes in VW and Audi parts and makes his own turbo back exhaust systems for them and has alot of experience in exhaust fabrication. The picture is not for an rx-7 so i dont wanna get flamed up the *** about that, but its to give u an idea of what it will look like.

 

Where is this guy's shop at in Miami?
I wouldn't be interested, but I AM curious where his shop is at.

 

his shop is in coral springs, www.unforgettablesnp.com.
Hes a maniac with the 1.8t.

 

Is it wise to shoot flames out all over the underside of your car?

 

what is the point of this thing? why not just take out the catback?

 

i was told not to do this... do to no back pressure

 

because that would loud as hell and you wouldn't want to drive around like that everywhere you go, this way it can dump out at the midpipe at the track, and you can block it off when you are on the street.

or atleast thats what i think

 

That's exactly what it's for. You go to the track, remove the plate held down by 3 bolts, and you got an instant open exhaust.

The trick is our engines. Whoever buys these things would have to make sure they are running rich enough with the open exhaust but not to the point where when you close it back up that it will run rich dirty like a ****. You also need to consider about the fact that Boost will have to be controlled in some type of way.

It's not just bolting it up and jumping to the track for us. We gotta make sure we aren't going to lean out either by insufficent amount of fuel or by over boosting. This would give an extra headache to Boost creep for those with the stock wastegate.

 

Just as yuo can easily remove the 3 bolts to take the plate off, you can easily just add a pipe to that same flange to safely exit the exhaust out of the side of the car and even have it pointing downward to ensure you get as little flammage on the body as possible.

 

thats why the end is pointed down. Flames come out my exhaust and i have a hi flow cat, it causes nasty updraft and my bumper is discolored, better on the pavement than my bumper

is that easier than unbolting 3 bolts?

When blocked, the dumptube retains some backpressure, but not as much as a cat would. When open, retains basically no back pressure and is loud as hell. Im not putting it on untill i get the AVC-R unit. Then you get a chance to hear a real screaming rotary whenever you want.

 

I knwo a guy with one on his RX-7 single turbo, but his has an actuator that only opens up above a certian RPM at WOT, this is to improve backpressure in the low RPM range and thus give more low end torque. His is actually on the DP though, which I found odd, and IMO not very safe due to flamage, but it seems to work. Very loud.

 

Quick 93 FD, you shoot flames with a high flow cat?? Whats your setup and what manufactorers?

 

would this be too little restriction with possible boost creep. i mean whether or not you are using a controller. i saw bost creep, with a profesionally tuned avc-r, and was worried abput engine damage. the lack of restriction IS something to worry about...especially with stock twins and not having the wastegate slightly plumbed to bleed more boost..

 

Thats a pretty good idea for track use. Although personally I would rather have it on the downpipe so I could run a high flow cat for daily use, then open up the pipe for extreme power. Not much different than my wastegate, which throws flames under the car anyways.

 

Malachi151, I think you are referring to an open wastegate. The pipe from the wastegate is let out into the atomosphere instead of being route back into the downpipe.

David

 

most dsm cars have this and at wide open throttle it is loud as hell at full boost and they have it on there down pipe.

 

I have a greddy stock mount intercooler, hks downpipe, Magnaflow hi flow cat, hks super drager cat back, upgraded fuel injectors, reprogrammed ecu, thast about it. Yeah, i used to be able to throw flames just by revving up to about 7k in the school parking lot, but now its running a little less rich. THeres also a black spot on the curb when i park every day, lol. Ive heard that ive shot flames a little less than a foot long when dragging on a closed road, but ive never seen it, i did see, when my friend revved it, a fireball that never really went all the way out of the muffler, but it looked sweet. heres a pic of the super drager
https://www.rx7club.com/forum/attach...&postid=644983

 

The domestic guys do this all the time, with something called an exhaust cutout. Turn a lever, voila! instant exhaust dump.

Look into one. Kudos if you manage to find a 3" wide one that isn't cast iron. I guess domestic guys aren't as sensitive about weight as we are.

 

the one that will be made will be 3" steel.

 

Yeah, domestics have been doing this stuff for eons. I tend to agree with Flybye on this stuff about fuel, etc. You'd either have to dyno tune your ride with the dump open to get your maps all set up (would help to be able to quickly load them via datalogit, if you have a PFC), or you can try tuning on your own. The latter choice is risky as you won't be able to see if you're leaning out (whereas you could go wideband on the dyno and know for sure).

It's a neat idea, but unless you plan on tracking your car all the time, probably not worth the time and effort required to ensure you don't pop your motor.

 

it would be cool if the dump could reach all the way to the side of the car or close anyway so that the flamage would be shot outside from underneath. kinda like nascar and any other racing for that matter.

 

could be done easily. the 3 bolt pattern is a standard size and u can get the piping at home depot. but i like my motor and i dont wanna blow it, if he makes me a midpipe, ill prolly tell him its a no-go on the dumptube and ill have him make one w/o dumptube.