WOG92

Hey guys,

I'm in the process of doing a few things to my newly purchased RX7 FD3S. I'm looking at buying a SMB dump pipe to replace the standard dump pipe and therefore require a better flowing exhaust. If I were to buy this front pipe to replace the current restricitive front pipe do I need to get an aftermarket ECU or have it tuned? I remember reading that you can't change the front pipe and drive the car as it' not good for it. But I can't find that forum/post aymore..

Here is the front pipe I'm looking at getting:
http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT

All help much appreciated, Paolo

WOG92

It's a JDM FD3S if that changes anything.
I just need to know whether I can bolt it on and drive the car and everything will be sweet or if I have to get it tuned etc. This is my first rotary so new to these cars

MR_Rick

iTrader: (7)

That's a mid pipe on the link not a down/front pipe.

You should have a catless midpipe already though. JDM model came without the cat on the down/front pipe.

If you are looking to replace the midpipe, then the issue is boost spike from the free flowing exhaust. I would highly recommend that you port your waste gate and get a boost controller to prevent spike and damaging your motor. Also adding a straight midpipe will make the car LOUD if you already have a catless downpipe.

WOG92

Thanks for your input. Just looked at my mid pipe, it is already catless even though it's stock. Which confirms what you stated about the JDM being catless. However I was going to get the one on eBay as it's 3" therefore better flow due to it's size. I'm not sure of the size that is on the car now but I don't think it's 3".

I will be porting my wastegate as I'm doing the "Rich-Mans" non sequential conversion.. As well as using a Greddy electronic boost controller. So therefore, should be ok

MR_Rick

iTrader: (7)

I think you are getting midpipe and downpipe confused. Downpipe= front pipe. In your case it is catless but your midpipe isn't catless. The ebay link you posted is a midpipe.

WOG92

Ok, so I was getting confused. As the front pipe is also known as the dump pipe/down pipe. Too many terms for one pipe if you ask me..

Current front pipe = Stock JDM (Catless)
Current mid pipe = Stock JDM (Factory Catless) however it is fitted with an after market high flow catalytic converter (Therefore currently has a cat)

New front pipe = SMB catless front pipe
New mid pipe = eBay 3" catless mid pipe

The diff back exhaust is a 3" Jasma exhaust therefore will work well with the new setup..

WOG92

Is it worth upgrading the stock catless dump pipe?

The average price is $400 for a second hand brand name dump pipe. Would there be much gains?

Mahjik

iTrader: (1)

Depends on what you call "worth it". IIRC, the stock diameter is 2.5" where as an aftermarket replacement will be 3" so there will be more flow. If you increase the diameter of the dump/downpipe and remove the hi-flow cat midpipe in favor of a straight through 3" midpipe, you can open yourself up for boost creep. Not everyone experiences it, but it's a possibility.

WOG92

What I mean by "Worth it" - will I get much gains/if any?

Boost creep, I will be using an electronic Greddy Profec B boost controller to minimise boost creep along with a custom ported wastegate. If I still get boost creep then I will restrict the exhaust until the boost creep issue is solved.

Thanks for your help and advice, much appreciated!

arghx

iTrader: (3)

If the exhaust flows too much, the wastegate will be overwhelmed regardless of your method of boost control. The only solution is porting the wastegate or restricting the exhaust again.

WOG92

I'm doing the rich mans non sequential conversion which includes porting the wastegate. I am buying a SMB dump pipe first and installing it to see how I go. If I don't get boost creep, I will get the catless 3" mid pipe. If I still don't get boost creep then everything's good. If I get boost creep, I will get a more restrictive muffler..

MR_Rick

iTrader: (7)

I had the Old Proffec B on my last FD and it did a pretty good job on keeping the boost creep away without the ported wg. But every car is different though.

twinsinside

iTrader: (34)

Be careful with boost creep.

If you want to go wide open exhaust the cheapest way to combat boost creep is restrictor plates.

Is this a track car or street car? If it's a street car I'd just get a high flow cat. With a high flow cat you don't need to really worry about creep and you've ported the wg already. Plus you won't have to deal with the noise and smell.

WOG92

Where do the restrictor plates go? In the exhaust itself?

It will be a street driven track car if that makes sense. So basically making it for time attack/strip/autox etc but I will still be driving it on the street sometimes.

My mid pipe already has a high flow cat, the previous owner got one put in.. Should I just get the SMB downpipe and leave the standard JDM mid pipe with the high flow cat that's already in it? From the sounds of it, that might be the best option..

riwanika

iTrader: (1)

I didnt see an answer to the stated question here, or I'm not reading it right. Factory ecu usdm with the pre cat removed, and factory exhaust maintained, <--- does this require ecu tuning or will it be safe on the stock ecu? Right now it feels clogged and too restricted to allow my boost to hold over 5k rpm, it's 170,000 miles on completely factory exhaust

bigolsen

iTrader: (1)

Hello. If I keep the stock intake and do a bonez dp with high flow cat and stock cat back I shouldn't have to worry about boost creep yet right? I'm guessing the stock muffler will restrict enough.....

Double_J

iTrader: (28)

I've owned a jdm car, and changed the downpipe to a 3 inch pipe. I did not notice any improvement at the time. If you were planning on modding a bunch of things to increase the performance then I would get a larger downpipe as well.

Also because it is a jdm car not all downpipes will even fit. They might need to be flattened a bit so they can squeeze in, thus also causing a small restriction

Mahjik

iTrader: (1)

Every car is different. While you should be fine, you'll just need to monitor your boost.