Exhaust mods

T

TV8

0
Hi only my second post but my other half Moley has been on here a while.
I need to fit a new exhaust to her Commer highwayman "Brian" and have a few questions before I start work on it.

We have accuired a stainless steel silencer from a TR7. Its 2" bore and is straight through. Anyone know the diameter of the original downpipe from a 1600 engine as I need to adapt from this to the 2" silencer.

I also notice that the Mini systems used by a few of you have two silencers, do you think it will make the van too noisy if I just use the TR7 box?

Another interesting thing on Debs van is that the exhaust exits on the passenger side making it a really short system, anyone know of any issues with this as it makes cobbling up an exhaust really easy.

Providing I stick to the original exhaust bore size for the pipework does anyone envisage any back pressure issues with using the 2" bore silencer?

Cheers
Dave
 
First of all Dave, welcome to the madhouse[8D] if you read through the topic below it should at least give you some ideas....my downpipe is 38mm external and my RC40 is 48mm external so I will have to sleeve down...not sure if being a 1600 yours will be the same or not..

http://66.129.69.181/forum/topic.asp?TOPIC_ID=6023

there is another couple of links in the above of how I did smurfs and how Panky did his, although neither exited the nearside there might be something that helps

PS...any old Fords on the horizon:D:D

''COMMER'EnSayThat''
 
Hi Dave,

I also copied Panky's design on our van with great results [8D], here's a link to my construction pics http://66.129.69.181/forum/topic.asp?TOPIC_ID=3478 but this has a standard exit via the offside.

When I was playing around, the single straight through was noisier than the original, whereas the dual silencer about the same but just a nice, deeper note.

Not sure about just a larger silencer but IIRC CommerRacer (Tim) has said that 2" system will rob power and that a 1.75" system should be good up to something like 150bhp (imagine that in a Commer [:0], oh Admin has with his V8 ;))

HolbayLogo.jpg

'Hunny' our Commer Hi-Tor by TorCars
 
Hi Dave :)
I would think the 1600 pipe diameter is the same as the 1725 (too small)
It depends how much noise you can put up with, but i would think it would be a bit too loud for comfort on its own. All you can do is try it using suitable pipe adaptors. 2" bore is ok for the silencer as the bigger bore makes up for the internal drag/turbulence, so no worries about excess back pressure.
It can go out any side you like :)

4650583641_dba2503b41_o.jpg

"You,re only supposed to blow the bloody SLIDING doors off"
 
Tim........my RC 40 is 48mm external and about 58mm at the tail pipe but at the downpipe end is 38mm...in your opinion will that still give enough back pressure? ...its very simillar to smurfs set up and it worked beyond all expectations....

''COMMER'EnSayThat''
 
There still seems to be a common misconception about regarding back pressure, NO engine likes backpressure (except 2-strokes) it,s totally negative energy against the engine. The less the better ;)

4650583641_dba2503b41_o.jpg

"You,re only supposed to blow the bloody SLIDING doors off"
 
Alas, but, to contradict yourself, you said that a 48mm pipe would result in a lack of power? ......I'm not being awkward at all.......I just dont get it? sorry to seem thick!!

''COMMER'EnSayThat''
 
Yes, a PIPE diameter that big would lower gas velocity, but just a silencer that big will not, as the silencer has alot of internal drag and restrictions :)
Keep the pipe size to about 1 1/2" and fit a silencer with up to 2" bore ;)

4650583641_dba2503b41_o.jpg

"You,re only supposed to blow the bloody SLIDING doors off"
 
OK...my set up is 38mm downpipe leading to weldylump 48mm leading to silencer leading to 58mm outlet.....does that 'sound' ok?

''COMMER'EnSayThat''
 
Advanced Member



United Kingdom
4759 Posts
Posted - 31 Aug 2011 : 21:16:26
--------------------------------------------------------------------------------

2" bore is far too big, you would lose power with that



To qoute your previous comments Tim...........so you reckon I'm doing the right thing???

''COMMER'EnSayThat''
 
that was a cokcup of a reply but, you get the gist ya?
:D ....please dont get me wrong, ...I am not trying to be clever or nowt...just want to get it right....[8D]

''COMMER'EnSayThat''
 
Colin, the trick is to keep the pipe as small as you can get away with, but have larger bore silencers to minimize the restriction.
2" bore is too big for a PIPE size but not a SILENCER size :)

4650583641_dba2503b41_o.jpg

"You,re only supposed to blow the bloody SLIDING doors off"
 
..and finally the penny drops and I get it now:I:D:D thanks for being patient and explaining ...

''COMMER'EnSayThat''
 
Ah awesome, i have loads of 1.5 pipe that i didnt know what to do with! And loads of 2 inch bore silencers haha! 2 silencers, straight and short as possible exhaust, exiting on the manifold side rather than going under the gearbox...
 
Origonal pipe is 1.5" bore and too restrictive, 1.75" is just right ;)

http://www.commervanspares.co.uk/

http://www.yorkshireclassiccampers.co.uk/
 
PS...any old Fords on the horizon

No Colin I havent heard from the guy so Im guessing hes decided to keep it, shame really as I did like the look of that car. Probably for the best as Ive got enough on with the Stag and Debs Commer and Ive got nowhere to put another car:)

Thanks for all the info re the exhaust mods, next question is, is the exhaust manifold on a 1500 engine the same as the one fitted to a 1600 as I have a spare one for a 1500 and might go down the porting route if the manifolds are the same.
Martin are the downpipes you sell the original diameter or larger?

Dave
 
Larger, 1.75" Only available as complete system though.

http://www.commervanspares.co.uk/

http://www.yorkshireclassiccampers.co.uk/
 
You must log in or register to reply here.
Back
Top