exhaust

[hotrodder13]

i want a new exhaust for my 1275. i want an lcb but they are only 1, 1/2 pipe. i want a 2" exhaust. so i would use an lcb but use a reducer the other way. ive been told i need back pressure for any power. so would 2" be to big and should i stick with the 1,1/2
tom

[bmcecosse]

Don't overdo the size - although I think this 'back pressure' thing is somewhat overstated! If the lcb is 1.5" - then just put the next size pipe on it and carry that through to the rear. My exhaust has a single Cooper S 'straight through' silencer on it - and I have to say (and never thought I would hear myself say this!) - the noise becomes quite 'wearing' on a journey of any length! I suppose I must be getting 'old'!!!

[jonathon]

We often use the 11/2" with a reducer , back to front into 1.3/4". 2" is too big for a 1275cc

[hotrodder13]

well i was looking at your site for the bends i want to make my own so i can do it any size. thanks for info 1,3/4 is better then what i got.

[linearaudio]

The problem you will have with a "big boy" 2" exhaust is that the exhaust gas speed will be too low at the bottom end. The cam relies for efficient working on the exhaust gas moving fast enough not only to clear the combustion chamber, but to promote the fresh intake charge entering. If you want the ultimate proof of this, try running the engine with no exhaust at all, you will be lucky to get it to run, let alone smoothly!
At the other end of the scale a 2" bore is much more than is needed to allow the engine to breathe at the top end. So bigger isn't always better!

[Mogwai]

I'm using a Maniflow system on the minor. I think it's an 1-5/8" pipe & works well throughout its rev range
The Midget I have has a big system but is matched too the state of tune of the engine (overbore,big cam etc) it doesn't do a lot below 3000 rpm then it realy wakes up

[flowersGTR]

ive got the maniflow lcb and twinbox system, mines a 1 3/4"
i can recommend it

[hotrodder13]

were can i get the maniflow lcb from. how much is it

[Mogwai]

http://www.maniflow.co.uk/

[hotrodder13]

thanks for the link might have to give them a ring

[callyspoy]

i had the maniflow LCB on mine, it seemed pretty tidy. i had a different one before where the angle of the exit was pants, where as the Maniflow one really seemed to fit well. that is my 2pence word!

[hotrodder13]

i think im gona end up making my own. i can get the flanges and all the bends and i can learn how to weld stainless. unless i can get a nice 1" 5/8 manifold cheeper then the maniflow one.

[bmcecosse]

Good luck with that ! You're in for quite a job.

[hotrodder13]

i was always goin to make the after bit but not the manifold. my dad can show me how to do it hes made his own. just have to make sure i get the right bends

[bmcecosse]

And a decent silencer

[hotrodder13]

one silencer will do me. just a stainless mid box.

[jonathon]

Could I suggest an aluminised silencer as stainless is much louder and raspy, steel more throaty, they last an awful long time too
PM sent by the way

[bmcecosse]

I built a system last summer -using a NOS Cooper S straight through silencer - it works - but it's pretty LOUD!

[jonathon]

Ahhh you 'boy racers' will play

[bmcecosse]

Well - it was only £3 - and local to me so no carriage! Had it in stock for ages - was intended for my 1340 Mini. It does become a bit 'wearing' (no - not Ware -ing!) on a long journey. I do have a complete spare stainless twin box system for my TR7 - may have been better to modify and use that! May get to it - if summer ever comes round again...........