Hey all

Had abit of a look around to see if there was any threads on downpipes but didnt have any great success.

Wanted to see if anyone has tried the aftermarket bolt on parts available, be it the ebay specials vs genuine gear.

I normally prefer the genuine stuff but it can be pretty pricey by time it lands here in WA Aus.

Here are both the genuine and ebays one im looking at:
FEED SONIC FP Stainless Front Pipe - FD3S RX-7 - RHDJapan

Stainless Steel Downpipe Down Pipe 93 97 Mazda RX7 RX 7 FD3S 13B REW Turbo FD | eBay

Obviously a genuine is always the go but my question is do you think the ebay one will be still nearly as good (and an improvement over stock).

The thing is the ebay one comes with a mid pipe which is handy and easy because I can cut and put a 100cell Cat in, (cat needed by law here) and I can then attach to my catback section, which is a nice mandrel bent system that come with the car.

Biggest concern is the expansion type chamber on the genuine one, does this make much of a difference? and any reason behind it. Every other car I have built ive just made direct 3 inch dumps off the turbo and has always worked well with response and flow.

You thoughts and knowledge is much appreciated!!

Even better if someone here in Western Australia had something to sell me?

-Matt

 

I haven't put an Ebay one on an FD, but my friend bought the Ebay downpipe/midpipe and when I picked the pieces up they were REALLY light.

Light is good, but it will be louder in the car than a heavier gauge DP/Midpipe.

I do have the Ebay catback on my FD, its ok. Not as high build quality as anything Japanese.

 

Thanks mate

How did it go for your mate? Did it bolt up ok and work alright?

It should sound fine because its just the front section I am replacing, then its got a good catback system on it.

I guess once I chop and weld it will show me how good it actually is haha.

Genuine always the best although some of that cheap Chinese made stuff can look alright with tidy welds etc

 

He hasn't used the Ebay pieces yet.

 

Racing Beat provides very good exhausts... I'd look into that.

 

Thanks mate, I have looked at racing beat before, looks like they have some good stuff but no front pipes, only catbacks, which ive got already. I also run into the problem of it being in the states, where as I am down under. Western Australia seems to be the furthest place from anywhere for parts.. However I did know this when I started, all part of the fun..

 

Rotary exhaust is ALOT hotter than the average piston engine. And changing the DP is a bit of a PITA. I'd recommend a proven brand of DP (Ebay is not an option) and a hi-flow cat unless you're a bit of a masochist. For a DP, look for thick flanges and the mounting ear for attaching it to the transmission bracket at the downstream end. They don't all have them. You have a RHD, HKS comes to mind. Have it heat-coated or at least header-wrap it before installation. Makes a significant difference in under-hood heat. And I recommend springing for the MAZDA gasket too. A little pricey, but you don't want to do it a second time fighting a leak.
For a cat, not many aftermarket ones will stand the heat and energy and fail in short order. And if it's your plan to pull it after inspection and reinstall just a test pipe/midpipe, read the FAQ stickys in the 3rd Gen. section about BOOST CREEP first. BONEZ makes a durable and good flowing hi-flow cat for the FD. I've been running one on my car for 12+ years. No experience, but have heard a lot of good on SMB as well.

 

Thanks mate

Im thinking I bite the bullet and order something out of Japan, or go SMB, there pricey but atleast theres a local source for them. Im not skimping out anywhere else on the build so I might splash out abit more on the exhaust to get something im happy with first time round.

Im stiil in debate about 3" or 3.5" but running a 100 cell hi-flow is on the list, even tho it wouldnt past emissions its best to have here because if caught without you can be find up to $10,000 per cylinder!? (gets into more trouble arguing the fact its a rotary). Then cat back exhaust with a cannon style muffler.

Yeah iv read about the boost creep, not sure if it will come into play on my set up. Going to see if porting of the wastegates is an option. Plus I intend to run them at near capacity (1bar) so not sure if at that pressure boost creep will affect me.

 

If you have a RHD FD you must use the Japanese or Australian downpipes that have the thin wide section just off the turbo.


Biggest concern is the expansion type chamber on the genuine one, does this make much of a difference? and any reason behind it. Every other car I have built ive just made direct 3 inch dumps off the turbo and has always worked well with response and flow.

Its not expansion so much as a way to snake around the steering shaft with the minimum restriction to exhaust flow.

Go SMB. I bought a 2nd hand SMB catted midpipe and it is amazing quality. The only exhaust I have seen that is better than the Japanese brands.

Go with the catted 3.5".

 

I have a 3inch HKS wrapped downpipe it's a thick metal piece and it's bolt-on the stock turbos