4th gen exhaust differences

The "S" express · Post by **honda-hardy** » Thu Oct 03, 2013 10:37 pm

ok. my mrs has a 2.0i bb3 ukdm and i have to replace the mid and rear sections. i have the opportunity of picking up a stainless mid and rear from a jdm bb4 that wiggs is selling. so what are the differences? what modifications to the flange or length are required?

'92 Si VTEC · Post by **jjmartin349571** » Thu Oct 03, 2013 10:46 pm

I believe the mid section will be too long if it's from a BB4, as they have stumpy cats compared to the UKDM's and the mid section is lengthened to account for this. When I took my BB4 to an exhaust shop with a drokked mid section they offered up a pattern part for a UK car and it was too short

If you can get the JDM cat as well you should be alright though??

All this is assuming that the donor BB4 hasn't previously had an exhaust and cat from a UK car donated to it at some point of course

*edit

Ooh I just realised you said 2 litre btw... My knowledge is based on purely on VTEC 4g exhausts

Also I think the flanges on JDM/UKDM cars are at slightly different angles now I think in depth more

I think a mid section/cat combo is the best bet if you're swapping JDM/UKDM bits

The "S" express · Post by **honda-hardy** » Thu Oct 03, 2013 11:14 pm

just had this pm from newkid.

back boxes are the same, the difference is the jdm has a longer midsection and smaller cat, with a jdm cat you will be able to fit but you may have to elongate the cat to down pipe holes.

so, @W1ggz could you measure the outer diameter so i can get a sleeve for it.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Thu Oct 03, 2013 11:56 pm

Newkid is of course spot on there.

Pics of jdm vtec cat studs lined up against ukdm vtec downpipe holes;

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Thu Oct 03, 2013 11:59 pm

Jj's also right that there's a slight difference in the angle of the cat flange, but that isn't an issue, the flexi can accommodate it. I noticed a couple of months ago that my ukdm has a jdm cat and catback on it (has done all the years I've had it, without me knowing it!)

W1ggz · Post by **W1ggz** » Fri Oct 04, 2013 6:31 am

There's not really any need to worry Sam you will see when I send you the pic when I get to work the flange at the end of the mid section that meets the cat has previously been cut off and some one has then clamped in the correct flange to fit the cat on the bb4 so you should be able to simply unbolt this flange and bolt in one to fit your car at the required length. What length is the uk cat as the one currently on the car looked quite Long so there is a chance it's a Ukdm figment already.

Post by **Merlin** » Fri Oct 04, 2013 8:55 am

I am not sure if the UK 4th 2.2 & 2.0 use different size mid sections, they have different part numbers

http://www.ludegeneration.co.uk/wiki/in ... n_exhausts

W1ggz · Post by **W1ggz** » Fri Oct 04, 2013 10:00 am

Could that be down to a different bore size?

Post by **Merlin** » Fri Oct 04, 2013 10:02 am

In think all 4th and 5th gen exhausts are 2.0" with the exception of the Type-S/S-Spec which is 2.25".

They have different CAT part numbers too.

W1ggz · Post by **W1ggz** » Fri Oct 04, 2013 10:12 am

The cat that was on with this exhaust is 35 cm long dunno of that helps Sam

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4th gen exhaust differences

4th gen exhaust differences

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