10 replies to this topic

[swast4]

Hi,

As you may or may not know I have a SC VX with a 3" Tullet exhaust with decated straight through exhaust that I am trying to get track ready (hopefully before this year slips away).

 

I have done lots of reading and I am just about to repack my silencer with new ZT-1 (that arrived this morning) and get a repackable silencer made to take place of the decat pipe.

 

I was also about to take it to someone to have one of the exhaust tips welded up (and a dummy left in place) as I've heard it can be quite effective. I've just measured the inside of the exhaust tips and they are only 61mm diameter (x 2 tips), instead of the 73mm (inside diameter, outside is 76mm) diameter of the rest of the system. So my thoughts are that the area of 73mm is 41.85cm2 and the area of 61mm is 29.22mm. So by welding up one of my tips will give a restriction of 30%, so no wonder it quietens it down. 

 

Am I missing something or is this not a good idea if I'm wanting to keep it free flowing and all the horses available ? Or do people chop the Y piece off and have the 3 " tip and no dummy pipe.

 

Adam

[smiley]

How much HP is your system to begin with?

 

[siztenboots]

consider the new honda civic fk8 , the turbo K20C1 2.0l runs over 320 now and very small exhaust size, 50mm , 2inch , standard Jap size.

 

the rear section is interesting in that it runs 3 tailpipes , with the centre being a smaller size

 

[swast4]

450 ish

[smiley]

The SC noise is a combination of pipe size, cat option, back box filling quality and the end tip trumpet effect.

With your 450, a 2.5" system is out of the question. (which would shave off a big chunk)

 

Next is the straight pipe effect, which adds noise, and sends very hot exhaust gas straight into your back box filling.

 

In all honesty, i don't think that blocking one of your tips is going to make that much of a difference.

 

Not sure if anybody else is running high numbers with a 100 cells  HJS cat in a 3" system. that could step in here with advice?

[Nev]

A single 61mm exhaust tip will deffo make a fair bit of restriction.

 

To make 450 HP you need 19,125 litres of air per minute approx.

Pushing 19,125 litres/min through a 61mm diameter hole means it will have to flow at 243 MPH!

And this doesn't even taking into account the gas laws volume change due to heat expansion, which will increase this considerably further.

 

 

Edited by Nev, 24 April 2018 - 09:58 AM.

[swast4]

Thanks guys, I did think it wasn't right, I'm hoping that the extra silencer where the cat should help and also a bend pointing away from the track meters but thought this was going to be on one pipe not 2, the other issue here is how to mount the bends as the tips are set too far back as standard.

 

I was hoping to not put a cat in because of the cost and things I have read about melting them !!

[smiley]

All the melting cat stories are about the cat that tullett put's in there by default.

So far the (way more expensive) HJS cat seems to be doing fine up to 400. Just not read about a 450 system yet. Those are more rare.

 

[Arno]

consider the new honda civic fk8 , the turbo K20C1 2.0l runs over 320 now and very small exhaust size, 50mm , 2inch , standard Jap size.

AFAIK the 2" pipe is used on the smaller Civic 1.5T engine model, not the 2.0T in the TypeR? I think that's a 2.5". Triple end silencer exhaust is done for (interestingly enough) noise reduction. Setup is done so under part load the exhaust stream and noise is through the smaller center exhaust pipe with the most silcencing. As the gas flow increases the swirl in the center silencer becomes a blockade and the gasses are routed through the outer 2 silencers. Quite nifty to create a 'two stage' exhaust system without an active flappy system. Bye, Arno.

[siztenboots]

 

consider the new honda civic fk8 , the turbo K20C1 2.0l runs over 320 now and very small exhaust size, 50mm , 2inch , standard Jap size.

AFAIK the 2" pipe is used on the smaller Civic 1.5T engine model, not the 2.0T in the TypeR? I think that's a 2.5". Triple end silencer exhaust is done for (interestingly enough) noise reduction. Setup is done so under part load the exhaust stream and noise is through the smaller center exhaust pipe with the most silcencing. As the gas flow increases the swirl in the center silencer becomes a blockade and the gasses are routed through the outer 2 silencers. Quite nifty to create a 'two stage' exhaust system without an active flappy system. Bye, Arno.

 

 

iirc , its also oval section

[Exmantaa]

That exhaust tip is only a small length of the exhaust. And the gasses will have cooled down a fair amount compared to the manifold exit.. It will be fine and make less noise without the Tullett double trumpet.

 

Ps; 450HP is quite something. Have to read-up on your build.

 

Edit; You've bought Richards red Harrop VX; now I see..

Edited by Exmantaa, 24 April 2018 - 12:31 PM.