JDM Downpipe - Honda Prelude Forum

[SUB[EX] · 06-22-2003, 09:40 PM

Hey has anyone noticed how FAT the JDM downpipe it? The header is weak and the Downpipe is HUGE. Why is this?

Jon Like Wh0a · 06-22-2003, 09:42 PM

would you happen to know how much bigger it is than the USDM downpipe?

Zimmlude · 06-22-2003, 09:47 PM

I did notice that. I think it is because the runners are kinda squished to increase ground clearance. They have a kinda oval crosssection.

4bidden · 06-22-2003, 09:52 PM

Yea, I did notice my JDM was friggin huge. I guess its part of what adds the 7hp to the JDM engines eh?

[SUB[EX] · 06-22-2003, 11:27 PM

possibly, i dont see any reason to get a different downpipe. Most of the aftermarket ones i see are smaller.

Yea im curious what the size difference is compaired to the US one.

achemze · 06-23-2003, 02:49 AM

I saw this thread, and wanted to post 'get over the jdm craze' ... you mean something jdm is actually cool?

I'd definately be interested ... Couldnt us USDM guys swap the header/exhaust for a cool 3hp gain? I'd like to take that down pipe and saw it off into a straight-pipe.

AccordSleeper · 06-23-2003, 01:11 PM

the JDM downpipe is 60mm and it does make a difference.

why else is SMSP making a header with a 2.5inch collector?

a greddy header v. a JDM header yeilds virtually no change. the larger primaries on the greddy seem to make up for it's smaller downpipe.

alphajesse · 06-23-2003, 01:54 PM

Maybe that's why the spoon header is only the top half...

Zimmlude · 06-23-2003, 02:12 PM

Now that is funny. I was kicking myself for not getting a header when I did my swap and here I find out that the JDM is just as good as the Greddy anyway.

Some good info anyways.

alphajesse · 06-23-2003, 02:43 PM

The spoon upper section might do you a lot of good, then.

Zimmlude · 06-23-2003, 02:44 PM

And how much does that cost? I doubt I can afford it but I would like to see about it anyways.

[SUB[EX] · 06-23-2003, 09:08 PM

I have an extra but its got some nasty dents in it. I was keeping it around so i can use the bottom flange off it when i finally get better exaust. I have the SOHC flange welded on now.