10 replies to this topic

[Jumpinjacks]

1994 Mini Sprite 1275
Right, so i've been looking at all sorts of different exhausts recently, as I have a standard setup with a cat. And from what I can work out a 1.75" diameter will give the optimum power, but I read that about the 998 engine, would it be the same for the 1275 or should I go slightly bigger?
Also which manifold to go for, as I have seen some mixed opinions whether a LCB is better or the rc40 one on a 1275. I know maniflow is the best, but a little too pricey for me at the minute.
Is a centre exit single box the one to go for, or is a twin box side exit better?
Sorry for all the questions.
Cheers,
Adam.

[Bungle]

manaflow LCB with RC40 exhaust

[lolipop]

I used to have a cooper freeflow but changed to an Maniflow LCB, I think I lost some torque in the process so not sure it was worth it, had a single box RC40 which was noisy so added the centre box, made it quieter and got some torque back too. Side or centre exit wont make a difference.

[Cooperman]

I used to have a cooper freeflow but changed to an Maniflow LCB, I think I lost some torque in the process so not sure it was worth it, had a single box RC40 which was noisy so added the centre box, made it quieter and got some torque back too. Side or centre exit wont make a difference.

100% correct, and 1.75" internal diameter is the ideal size.

[Jumpinjacks]

Would a full 2" maniflow system be too big?

[Cooperman]

Would a full 2" maniflow system be too big?

Yes, a bit too big unless you are going to bore to around 1380 and use 7000 rpm.
For a 1275 to 1330 cc engine using up to about 7000 rpm, a 1.75" is best as it gives the optimum gas velocity down the pipe.

[MiniLandy]

I used a Sportex LCB (bought new through their eBay shop) and a single box RC40. Asembled with "Fire Putty" assembly paste, and with the lcb Y peice welded to the link pipe, it's fairly quiet and gives a good power/torque range.

[Jumpinjacks]

Would a full 2" maniflow system be too big?

Yes, a bit too big unless you are going to bore to around 1380 and use 7000 rpm.
For a 1275 to 1330 cc engine using up to about 7000 rpm, a 1.75" is best as it gives the optimum gas velocity down the pipe.

Is the 1.75" the internal diameter? As the guy selling the maniflow has said that he measured the backbox pipe external, and it was around 2"

[Kam]

The back box end pipe is always gonna be bigger than the main section, get them to measure the other end

And yes a 1.75" is what you need, its also what you get with the 1275 stage kits

[Ethel]

Pipe is measure externally, typically it goes up in 1/8th steps so it sleeves together (1/16th wall thickness). A 2 inch pipe shouldn't be too bad it might cost you a tiny bit of torque at lower revs.

[Jumpinjacks]

Thanks for the help guys, I have ordered a new cooper freeflow manifold, Rc40 downpipe and twin box exhaust all from minispares. Should do the job nicely