Who makes the best downpipe???
 

I am interested in purchasing a new downpipe and I need to know what your opinions are on the best one for the job. Thanks a lot for the input

I'm looking for one too. I hope you get some responses. I'll keep my eye on this thread.

Jeff
'93 R1

They are all very good, and similarly priced. Just make sure to get a stainless steel one. Pettit's is widely used and liked, I have the one from RX-7 Fashion, which is the only one to retain the exact same dimensions of the stock precat flange. This allows for more gasket sealing surface with the exhaust manifold. The drawback to it though is that it is more difficult to install, and now I have a problem where I cannot remove or install the O2 sensore without removing the whole pipe.

I have the HKS pipe and from the looks of it, the design doesn't appeal to me as very flow friendly. I've seen the M2 DP and it looks like more of what I'd want now, but I have the HKS, so no need in switching. Just my .02

Most all of them are very similar. I went with the M2 DP because of the SS construction(a must), --perfect-- fit(and no one else had reported any problems) and ease of install(no removal of the turbo manifold studs)

I'm using the Bonez downpipe. It was a kit for the downpipe and high-flo cats..

I don't drag at a track or anything, so I stayed with the street legal stuff for my area:

http://www.rx7.com/cgi-local/3catalog.cgi?cat=4&part=1

I have the Bonez racing midpipe constructed of stainless steel from RX7.com it has a 3" piping. Excellent fitment.

i liike the rx7fashion one.. its got the exact flange as stock...and the pipe is 3in all the way to the flange...u have to see it to understand..very nice construction....to change the o2 u just need to jack up the car and u have easy acess 2 it..


im selling mine for 200 if anyones interised..

i personally like the Pettit one... Its stainless steel and not too hard to install.

1FAST7

I could be wrong, but I'm almost 100% certain that downpipes are 50 state illegal... unless you live in an area that has no emissions requirements.

Not that anyone would be able to tell you have one unless they stuck their head under your car, but they are illegal all the same.

As far as best... as everyone has said, as long as they are stainless steal, they are all about they same... I've heard that mild steal flanges may be better than stainless flanges because they don't expand and contract as much due to heat - most SS DPs have MS flanges. So beyond that, the only thing to take into consideration is ease of installation. M2 seems to have the best in that category... you don't have to remove the retaining bolts, and are therefore less likely to break something while pulling out the old one.

-Brian

First off, I live in Michigan and thank god they don't have emissions testing here. But really I think that the Pettit and the Bonez sound pretty good. Thanks a ton.

Todd

Honestly I'm not quite sure, but Bonez does have this on their full exhaust replacement system:

Note: These systems are EPA Legal for Street Use.

I'm not 100% sure, but I believe, at least in my area it's mid-pipes that are illegal, not downpipes.

eh hem... and I quote:

"...The best way to state this is that any changes to the exhaust from the cataytic converters forward (or intake) system will alter the emissions of the engine and are therefore illegal on all public roads anywhere in America. The only legal change is the rear muffler and the pipe in front of it...."

and, direct from rx7.com's downpipe page: "Note: Racing use ONLY! Not recommended for Street use."


HOWEVER - on the complete system page (which I believe is what you're refering to), they mention that it is street legal even tho it has a downpipe.... My guess is that somehow they figure that the cat takes the place of both the pre-cat and the main cat.... if you live in CA, I would double check because I can't see how a high temp cat would be able to heat up fast enough to pass cold start emission. (but again, not like anyone's every going to find out anyway)

Downpipes are not street legal. Period.

There are thousands of cars out there with illegal exhausts. It's not the end of the world.

IMHO, the best downpipe is M2's. High quality, no more expensive than any of the others, stainless steel. If you love your car you'll get it Jet Hot 2000 coated as well. My engine bay is noticeably cooler.

BTW, I researched downpipes for months. Just trying to save you the trouble...

I have the Bonez mild steel down pipe from rx7.com. I love it. It was a little bit hard to install, but i was kind of my fault. The kit comes with new studs so I put the studs in before I installed the pipe. When I went to put the pipe on it would not fit between the studs and the side wall of the car! My friend had to pull the engine over while I slid the pipe in. Then every thing worked fine. The O2 sensor is very easy to get to. Guess they make use of all the space they can to make a smoother turn down? This is why it was tight. If you put the studs in after you put the pipe in place the fit would be almost too easy.:rolleyes:

I just purchased and installed an HKS unit. Bought it for $200 (cheap!) and was damn easy to install. Its is not as straight lined as the otheres as it is set up for right hand drive cars in Japan, but I think you guys are splitting hairs now. I think the difference between the HKS and any others is maybe 1hp, I could be wrong though. I would go with HKS, best bang for you buck IMO.

Can't agree with that more... it is the best bang for your buck and was a snap to put in.

you shoudl put a poll up so i can see what people like the best and then read their comments later, its to confusing to try to count how many people recommended each type of downpipe