What is included in the box when purchasing a new HKS downpipe for the FD? What type of hardware should I buy or need for this install. Gaskets needed?

 

If you're buying it new, then the vendor should be able to tell you for sure.

You should also get an answer from HKS:
http://www.hksusa.com/products/?id=661&rsku=3793

 

Re: gaskets and hardware, I'd replace them.

If you simply pull the same downpipe and reinstall it the same way, it should be ok to reuse it if you put things exactly where they were. That's not the case here.

Some folks have had good experience with copper exhaust nuts and exhaust studs. They're much less expensive than stock.

 

How many nuts and studs will I need? How many nuts and studs for the upper portion and lower portion?

 

4 nuts 4 studs and 2 of the big nuts. ill get you the part numbers in one minute you can order them from ray from malloy mazda. All the hardware came out around $80 not including the gaskets.

 

(4)9YA9-21-008 Stud
(4)JE10-40-355 Nuts to Stud
(2)JE11-40-355 Nuts to middle section

These are the OEM parts from mazda and quanity needed. If you get the turbo to downpipe gasket from mazda it should be about $80-$90. I bought my gasket from pineapple racing (made by pineapple racing) for $30.

Hope this helps.


~chris

 

Take care with the pineapple gaskets at the upper end of the downpipe. Unless they've changed the material since last year, they're not designed to handle the backpressure of an exhaust containing a catalytic converter. Mine lasted about 5k miles doing a bunch of autocrossing. My car has a stock cat.

The one between the downpipe and main cat is much more affordable. I'm using a copper one from SCE gasket that seals in the presence of slightly warped flanges.

 

Forgive my ignorance, but when taking my old downpipe off, will the studs acutally be in the upper portion of the downpipe?

 

(2)JE11-40-355 Nuts to middle section
Are you referring to the nuts that connect the downipe to the cat?

 

Did you buy a new gasket between the downpipe and cat?

 

When removing the downpipe, the studs may come out when loosening the nuts that bolt the downpipe to the turbo. It is normal that the studs do come off during this process.

Youll have 4 studs. two up top and two on the bottom.

 

and yes the 2 nuts are the ones that go to the cat.

 

yes replace the front and rear gasket. The prices that follow are from ray crowe of malloy mazda. By far the best place to get your OEM parts.


Front gasket $83.68
Rear gasket $8.34


If you order your hardware from him it should cost $10 for shipping. Usually get my stuff across the country in 2 days.