The previous owner of my car had installed a JDM downpipe back when he did the engine rebuild with a JDM motor. I spoke with him and also read on here that the JDM downpipes don't have the pre-cat section that the US models have so there's no need to worry about the problems they cause.

I still however did want to find out further what you guys thought about keeping the JDM downpipe or replacing it anyway with an aftermarket one? I just wanted to know what would be the goods and bads about keeping it or replacing it?

The only mods on the car are a greddy PE exhaust, and a JDM y-pipe. Other than that the engine is stock. Thanks in advance

 

keep it.....

 

The JDM downpipe is a bit funky in that it is squished into a weird shape in order to avoid the steering column (as the steering is on the right).
While the JDM dp doesn't have a pre-cat, their funny shape means that an aftermarket one is probably worth it.

 

It is a different shape but I didn't notice a difference changing my jdm dp to a regular aftermarket dp.

I'd say keep it.

 

If your car is rhd then keep it, if its lhd get a usdm downpipe that is not bent in for the steering column. While you may or may not feel the difference, the usdm has to flow better with less restriction which will be better in the long run as you progress with modifications to your fd.

 

Keep it for now and spend your money somewhere else.

 

The car is a standard US LHD. I did notice the funky shape of it when I got under the car. I was mostly concerned about it being a reliability issue, but If it's only a very minor air flow change because of the shape, I think I'll end up keeping it for now until I do some bigger engine upgrades. Since the cars basically stock I don't think I would notice any difference.

Thanks for the help

 

I doubt you'd see any performance difference if your car is mostly stock. If there's no other reason to remove it now, leave it. If you have have to pull the motor or remove it for some other reason, get a North American version and have it heat-coated and/or wrapped.

 

I don't mean to thread jack, but I've searched and could not find a clear answer.

I drive a RHD car with stock down-pipe(j-spec DP). Would it be best to leave mine and bolt an aftermarket mid-pipe on it or get an HKS one and use a midpipe on THAT, I already have a MazdaSpeed cat-back.



this is just for now as I will be going Single within the next year.


Thanks in adavance,

 

Pulling an RHD downpipe with the engine in has to be one of, if not the most, frustrating thing to do with the engine in.

the JDM stock one is not restrictive and has it's own heat shields on it so there's no reason you HAVE to replace it. If the engine is out and you change it to an aftermarket one you'll need to at least wrap it to keep the heat down. While my engine is out I'm having everthing ceramic coated including the dp, manifold and heat shields. Hopefully that will work better than wrap.

Long story short, I'd leave it unless you're planning on pulling the engine or theres a problem with exhaust leak or something.

 

keep it the main reason to replace it would be to remove heat caused by the pre-cat since the j-spec did away with the precat nothing to worry about.. keep it use the money in other places

 

could you splice it with a US version and have the best of both worlds?

 

If your interested I have a downpipe on sale $50.
These wont work with the stock cat, but fit fine with a midpipe or high flow cat.

http://www.rx7store.net/product_p/dpfd3s.htm

I have about 4 of these in stock.

 

Thanks for the answer guys. So, midpipe it is!

 

If you haven't already, don't forget to read up on boost creep. I know your planning on moving to a single and presumably an adequately sized waste-gate, but until then..........

 

I have read up on it already. Thanks. I'll either be getting the restriction plates to put in the exhaust line and possibly port my waste-gate.