Good morning! I have the downpipe shown in the photos attached. When I bought it (EBay, 10 years ago, yes, I know...), it was listed as a Pettit. Would anyone be able to confirm this? It's 36" x 3" with 1/2" flanges and weighs about 8#. I've sent Jet-Hot a request for quote for coating.

From searching the forum, it sounds like I need bolts to replace the stock studs. Any advice appreciated. Do I really need a new $100 turbo/downpipe gasket? Yikes.

I'd like to have all my ducks lined up before I attack this, pay for coating, and not be screwing around with fit issues. Thanks for any replies.

On the other hand, maybe I should just wrap the pipe? Believe it or not, I have had the following items in my cart at Amazon for 10 years
https://www.amazon.com/gp/product/B0039Z1UHA/
https://www.amazon.com/gp/product/B000MY1RB0/

 

It's most likely a Pettit. It's definitely an American-made exhaust, that exhaust won't fit a RHD car. Looks well made.

I can't recommend Jet-Hot enough, I've had multiple downpipes coated by them on my car and friend's cars and it's crazy durable and crazy effective. Yes it costs more than doing a header wrap, but IMHO it's so much better quality-wise. I can't stand janky looking itchy header wrap.

All that said, the Pettit downpipe is a little iffy with fitment. As stated you have to use bolts in some spots and studs/nuts in others and getting to the fasteners is tricky. HKS's downpipe on the other hand fits awesome and you have a straight shot with a ratchet on all 4 fasteners. Picture so you have an idea -



The only other thing I recommend with downpipes is having a 2nd bung added for a future Wideband O2 sensor. I typically put them on the end of the downpipe just before the main cat, they are a little bit off straight up, it will go between the trans tunnel and the trans. Best way is to test fit the downpipe on the car, use a sharpie to mark where the sensor should be, then have a local muffler shop weld a bung on that has a plug. Have the whole thing coated and you can run the plug or have the sensor installed for a Wideband gauge. If you aren't needing or planning to run a wideband (just staying stock/near stock) I don't know if I would bother.

All that said, personally I would get one of the Japanese downpipes like the HKS since fit is so much better. Pettit generally works well but it's hard to get at 2 of the fasteners, sometimes the nut or bolt hits the downpipe and they want you to use a socket head bolt which sucks, etc. etc. It's a lot of compromises. And the HKS downpipe is reasonably priced and easy to get - Banzai Racing has them new for $240.

As far as the gasket, if the gasket is solid, not blown out or damaged, it's totally re-usable.

Dale

 

Thanks for the reply, Dale. More to stew about... :/ Does anyone ever just gut the pre-cat? Just spitballing here.

I don't intend any radical mods, just reliability.

 

I think the pre-cat is worth some serious money in scrap nowadays. Definitely not worth gutting.

It's also a giant chunk of cast iron even when gutted. Just simply going to a plain downpipe helps in underwood heat, ceramic coating even more so.

IMHO I would get a ceramic coated HKS downpipe and bolt it on and be done. Sell the Pettit downpipe. Don't worry about the wideband port and stuff.

Dale

 

no! save it for the people that need it! in California we have to run it

 

yes please! I've had a bonez dp sitting in my trunk for nearly a year because I'm due for smog soon and just didn't want to risk it. I know some folks have passed with an aftermarket dp but last time I smogged numbers were a little high.

Grant it.. smog is every other year but I'm not sure I want to be switching between dp that often in preparation for smog. IDK, is it worth it? My car is all stock.

 

yeah its like 50/50 if the tech lets it pass the visual.

 

The smog shops I have used in the South OC area always look very hard at my JDM Mazda downpipe, but it looks like it belongs there (it is OEM, after all) and they can't tell if there is a catalyst inside or not. I have no doubt that I would have failed smog check with an aftermarket downpipe on any of these inspections.

 

I'll offer an alternative to Dale's advice, with a disclosure: I took his advice with the HKS dp and got it ceramic coated for more power and the wideband.

1. Jet Hot offers a lot more options in coating, but they are not the only kids on the block. I went with Calico Coatings, because their turn around time was faster, they were a little cheaper, and they are from my home town. https://www.calicocoatings.com/index.php The downside with Calico is that they only offer in one color, but no one sees the downpipe anyways.
2. If heat management is your only concern you can always pick up a RHD OEM downpipe for much cheaper. Plenty of people scrap them for a performance downpipe or go single turbo. They already have a thermal barrier shield in place.
3. Installing a downpipe is a huge pain in the a$$. Dale is right, it is much easier to install a RHD pipe in a LHD car than the US made pipes, but it is still a pain. There is very little room to work with and the bolts are always stuck on the studs. If you plan on pulling the engine soon, wait until then to replace the downpipe and use what you have on hand.

Here is a picture of my Calico Coated HKS pipe next to a RHD OEM pipe.

 

I wish I could make another thread like this of auto exe vs Mazdaspeed intake. Unfortunately the Mazdaspeed continues to evade me.