5 replies to this topic

[george91]

Ok so I understand just how many exhaust threads there are but I just couldn't find my answer in any of them and i need the opinion of someone with some experience if possible, I have a 1275 carb motor with the equivalent of a stage 1 kit, and I have a maniflow manifold and link pipe to the cat with a dtm cat to back exhaust, this came with the car and I don't like as its a bit chavvy for me looks wise and unnecessarily loud.

The plan was for me to get a cat removal pipe with a cat to back system so I can put the cat back in for the mot's (mines a 1993 car so I need to have the cat for the mot, correct?), so I found the playmini 3" cat to back system but I was unsure if this was standard bore until the box then into a 3" rear pipe or not, and whether this would give me enough back pressure and not to end up reducing power.

Link to the exhaust: http://www.minisport...MSLPM40-44.html
If anyone can help me this would be great. Thanks, George.

Edited by george91, 28 November 2009 - 03:14 PM.

[R1minimagic]

That link pipe has a flange on the end the same size as the catalyst so i would imagine it is standard size pipework and then just 3" on the exit pipe.

It doesn't really matter if you go too large diameter in that region of the exhaust, the important part is to get the sizing correct in the manifold area. Going too large there can reduce power as you need to make sure flow rates and gas speeds are optimised

I have used the Play Mini exhaust on quite a few cars now and the power was always as expected on the rolling road.

Edited by R1minimagic, 28 November 2009 - 03:44 PM.

[Sherlock]

The 3" measurement only refers to the tailpipe, which may slow down the exit gas velocity a bit, but unless you're into serious competition & looking for the last possible couple of bhp, you probably won't notice it & it should be better than what you already have on there.

[george91]

That link pipe has a flange on the end the same size as the catalyst so i would imagine it is standard size pipework and then just 3" on the exit pipe.

It doesn't really matter if you go too large diameter in that region of the exhaust, the important part is to get the sizing correct in the manifold area. Going too large there can reduce power as you need to make sure flow rates and gas speeds are optimised

I have used the Play Mini exhaust on quite a few cars now and the power was always as expected on the rolling road.

Great thanks for your help R1minimagic, i was worried as i didn't want it to have the opposite effect, i have the correct manifold its a maniflow lcb and link pipe specifically designed for carbureted mini engines so that gives me good peace of mind, it should only be LB from the cat to back.

Edited by george91, 28 November 2009 - 04:05 PM.

[george91]

The 3" measurement only refers to the tailpipe, which may slow down the exit gas velocity a bit, but unless you're into serious competition & looking for the last possible couple of bhp, you probably won't notice it & it should be better than what you already have on there.

Thanks Sherlock, yeah thats what i was thinking glad you can clarify that for me, i think anything should be better for back pressure than my dtm box i have atm, i'm not after a 110% perfectly suited exhuast as the spec on the engine is going to be built up slowly and it should suit the exhaust better once its how i want it to be.

[Sprocket]

I would leave the cat on, you wont gain much removing it other than the hassle of having to put it back on for an MOT