Hello everyone,

I just wanted to see what the going preference for a downpipe is....I remember reading somewhere that the ceramic-coated ones were actually the best for thermal properties as well as corrosion resistance.
What are your preferences based on price, thermal properties, and corrosion resistance, performance gains, etc? (assuming they are all around 3")


Jon
'85 GSL-SE
'93 Touring

 

stainless seems to be the all around favorite because of its longevity. many also use the heat wrap that companies such as summit sell to further reduce under hood temps. hope this helps

 

well, they are all pretty much the same as far as performance goes... at least to the point where you won't be able to tell the difference between them by driving.

Mild steel pipes are more likely to corrode but expand and contract less than stainless. If stainless gets too hot, it turns into mild steel & corrodes.

Either way, the downpipe will more than likely outlast the rest of the car regardless of what you get or how you coat it (that being said, I went with a stainless steel & jet-hot coating - a bit of overkill, but oh well). So beyond performance and material, the most important issue is fitment. The M2 & HKS fit perfectly. I've heard that the pettit and Bonez fit well also, but I have no experience with either of them. The M2 is stainless and has a more direct path than the HKS (which is mild steel), but again, you won't be able to tell the difference.

I paid $250 for my M2 (it's normally $300, however) and $60 to coat it. One thing that isn't mentioned often is that the nuts that you remove are of a certain compound that doesn't last through many screw in & outs, so you should relpace those when you replace the DP - they are $4 each from Mazda.

Final note - it is possible to put it on yourself, however, it's not incredibly easy.... as a matter of fact, it's a supreme PITA... after a couple hours of trying, I took mine somewhere to get it done.

btw: this has been covered before, you should do a search

edit: you'll notice a very slight drop in very low end torque (assuming everything in your car is working correctly).... as in, under about 2800 rpm. But the decrease in under hood temps and the extra loud turbo suond is well worth it.