Cat replacement pipe for my Hachi (in the UK) - Weird

[Ian.G]

Hi folks,

my hachi (for some weird reason) has a cat pipe installed. I don't know why this would be the case as it was not a legal requirement 19 years ago. This was installed on the car when it came from Japan.

I need to get a replacement pipe made for this as I'm sure the CAT is robbing my engine of power.

The rest of the exhaust is a Trust Tubular Manifold and an Apexi N1.

I tried to talk to a PowerFlow exhausts dealer but they won't make any kind of cat replacement pipe (its their new rules). Even if they would it would mean grinding the flanges from my existing cat pipe making it unuseable.

I've also spoke to Fensport and they are most confused about a cat being present on my car. They don't appear to have anything that will mate up the 2 bits of my exhaust.

Anyone have any more ideas about where I could get one ?

[Ivan141]

Damn..making some flanges and welding a piece of pipe to them cant be all that hard..keep searching. BTW, Japan has different emissions laws, so it isnt all that weird that your JDM car has a cat.
You need someone who knows how to work with steel and tubing, knows how to weld. You can cut flanges from thick metal plates (lets say 6-8mm thick), and tubing isnt all that hard to find either (use an old exhaust if you must).

[86jay]

It would be easiest to order a proper cat pipe from either Japan or the USA it will be a direct bolt in fitment with no messing about. I have a feeling that T3 do a race "test pipe".

Jay

[Ian.G]

yeah - was considering taking the angle grider to the existing pipe and welding a new one - I don't want it to be a bodge. Think the T3 pipe is quite cheap so probably best.

I have a friend who can make me one - gonna see him tomorrow. He is a great welder. Hes made some really nice pulse tuned manifolds/extractors for many westfields - they are a proper work of art.

my friend half built this car for the barbados rally canival last year. Its soooo light you would not believe it. They had to carry so much balast - least they could keep it low down in the car. That R1 engine makes about 180bhp - the car weighs about 410kilos. LOL

[NoHachi]

Wow, nice carbon work.
I'm not totally understanding the exhaust on that thing. Is there just one widened section per exhaust runner or are there more? Difficult to judge from the photo. The exhaust builder must have extensive experience in building two stroke exhausts. Interesting..

..Why did they just make a tubeframe chassis with carbon layovers? Looking at the shapes in the picture it would be a perfect candidate for a full carbon tub. Box sections are pretty easy to make and calculate in carbon. We did it for a formula car, 80bhp (restricted, 65Nm torque..)@130kg, though it had a lot more carbon bits

[Ian.G]

Yeah.

the exhaust sure does look weird. He tried to explain in laymans terms why it was like that. It causes a pulsing of gas in the extractor that actually helps to suck just expelled gases from the head. Its weird ... but it works.

As for the car. It is based upon a Westfield SEi spaceframe. They are all tubular steel. It wasn't so much a design from scratch - it was more to do with seeing how much weight could be saved. The way the carbon is bonded onto the frame also creates a bit of extra ridigity.

[Ivan141]

Hmm..interesting exhaust indeed. Many dutch guys are a bit familiar with expansion exhausts since lots of us used to tune mopeds before we were old enough to drive cars. On a two-stroke the exhaust shape makes a HUGE difference in performance since getting the exhaust pulses just right ensures that exhaust gasses get out as fast as possible and incoming fuel mixture (which overlaps exhaust gas escaping) is optimised by the backpressure wave.
I havent thought it through for a four stroke, but it would only help to get the exhaust gasses out of the head faster. If that helps performance a lot, then I would like one of those masterpieces on my 4age.

[KristianAE86]

those exhaust are both rare & very expensive & also some of the very best ever made.


Kristian... former motorcycle mechanic.

[NoHachi]

The standard 4ag manifold already incorporates the pulse or scavaging effect. About every manifold out there does..This is a bit more complicated, looks like multiple sections are widened..don't know yet..

[Ian.G]

here is a different view...



didn't get to see him in the end Will drop him a mail in the week and try and find out a little more on the manifolds.

I think I just need to figure out all the bits I want and speak to T3.