im not sure if this been talked about but i was wondering if there would be any benifits of having a mid pipe that splits into 2 pipes and then back into one again. one pipe being a strait pipe and the other w/ a hi flow cat. then where the 2 pipes split up there would be an exaust valve that controls the amount of exaust that goes through the strait pipe. i think this would be useful so u wouldnt have to unbolt ur mid pipe all the time to put a cat on it. with the flip of a swich u could run a hi flow cat or a strait pipe. ive included a ghetto drawing on paint so u guys can understand what i mean better. lemme now what u guys think!!!

 

i dont know if theres room down there for two 3" midpipes. its only 4 bolts to change out midpipes id be content just owning two.

 

move to florida, no emissions---thank god.

 

yea u guys are lucky

 

Yeah, really lucky...

 

It is a neat idea, but it's so easy to remove the 4 bolts and swap back and forth that it's a moot point.

Dale

 

oh yeah you have to detach the airpump too :p

 

you still wouldnt pass emisions in ca if you go to a testing station(that is unless you have a lazy technician not wanting to look under the car for a cat).

 

I think it'sa cool idea, but there really isn't enough room under the car. Cool concept though!!

 

I've seen this done on the TV Show Trucks! before. The only way I can fathom it being possible on an FD is to run a straight pipe custom out the side of the car before the cat and put the valve there.

 

Great minds think alike. You know this is the exact idea I had for my custom exhaust set-up also. I believe this will work really great because the exhaust always exits the rear, plus the cat will also lower the exhaust noise some when in use. You could get the best of both worlds with an exhaust like that. The only thing I was going to do different than your drawing was to use two 90 degree bends to and from the cat. The sharper bends will lower the noise more. Also if you go with the sharper bends to the cat, don't worry about the slight loss in power because obviously you have the strait pipe side to compensate.

 

There's plenty of room if you get creative.

 

thanks t-von i was hoppeing i was up to something!!! well my drawing isnt really exact ya no? be it 45 degree bends or 90 it will serve the same purpose, and the noise level is exactly what i was getting at! i wouldnt have a problem swiching back to the stock cat to pass emissions but when ur just drivin around and u need/want 20-30 extra horses then y not?maybe i can try and get an exaust shop to produce one for me???

 

I'm going to make my own. Just need to gather all the parts ect.

 

i wolud but i dont have accsess to a welder im gonna try and find a used one some time... i wonder if there would be a big demand for them?

 

Should be room with the new metal core cats. FYI, PFS did make some protortype midpipes that split into two then back into one before the catback, helped keep the noise levels down.

 

This has been discussed before, one of the issues is that the valve to control the flow has to be able to withstand the really high exhaust temps of a rotary and the one you can buy off the shelf didn't hold up.

 

hmm thats interesting... do u no of one that u can buy that can with stand the heat?

 

Well Jedon some people just give up to easily. The simple solution is this.... the newer Electronic valves have a good heat rating. You can also have the valves heat ceramic coated. There are no excuses for this not to work.

Ok the next concern would probably be tuning. Simple! You tune the engine on the straight pipe side, then once the valve is close and the exhaust is diverted through the cat, the A/F ratio will automatically lower because of less flow and slightly more back pressure.

 

where in the heck do u even buy these valves ive seen em befor but i completely forgot where can some one help me???

 

Wouldn't a standard cut out vaulve work like the ones the LS1 bastereds use?
http://www.quicktimeperformance.com/QTEC/

 

Ooops!

 

Those cost a bit. I forgot the web page that had some for around $130.00. There are also some on ebay for cheap but, I'm not sure of the quality.

http://cgi.ebay.com/ebaymotors/Elect...spagenameZWDVW

 

ya i wonder if those ebay ones are good enough... does any one else have any sites in mind????

 

won't the air take the path of least resistance? how much will really flow through the cat?