has anyone got or had any experience with 'performance' exhausts, i.e stage 1 tuning kit.. http://minisport.com.au/prod71.htm

does a good set set of extractors and good exhaust make a difference??

cheers,
Craig

Yep, can make a bit of difference. In my opinion Mini's do need some back pressure. So big pipe does not always mean big HP. I use Janspeed headers and they seem ok. Maniflow seem quite popular too. There are some cheaper copies out of China that some people swear by also. I would recommend a 1 3/4 inch pipe with a 2 inch muffler straight system with good headers.

A 3-2-1 system would be better than the one shown in your link.

Just fitted a similar kit to my mini. Specs change for these sorts of parts when you buy them separtley, but as a bolt on stage 1 kit they are good value in my opinion.

depending on what you car already has will depend on the result.

if you car is all stock then yes you will see a gain and it will drive a little nicer - meaning it will breath/rev a little better-, and to top it off it will sound great!

good luck

_________________
'66 BRG Morris Mini Deluxe 60HP ATW

I have LCB extractors with a 2 inch pipe with a big baffled muffler to soften the note. Last year at hay the system departed from the extractors and it lost a considerable amount of power and missed a lot so a little back pressure is desirable.

_________________
Dean Hutton's first car was a Mini.

It's not actually back pressure you are after, it's gas flow. You need to make sure the gasses flow freely to aid in "scavenging", back pressure does not help you at all. The faster the gasses flow, the easier your engine will clear the cylinder on the exhaust stroke, meaning the motor does not need to use the the momentum from the power stroke to push the gasses out. This does not mean a massive pipe will mean better flow. Think of it like your garden hose. If you had a 4" hose with the normal amount of water flow, it will dribble out the end and not be a steady flow. When you use the correct size hose, the water flows out much faster and steadier. This is what you want to achieve. If you put your thumb over the end of the hose, the water cannot escape as easily so comes out at a higher speed, but the actual water flow slows down because of the restriction. This would be "back pressure" and is not good.

This can also be taken to a whole new level by tuning your exhaust to the extent of it creating a vacuum and actually sucking the exhaust gasses out of the cylinder, sometimes referred to as negative supercharging or vacuum supercharging. Read here for more info http://www.impulsengine.com/

But yes, a premade set of extractors and exhaust system like that will allow you engine to breathe better and you will notice a difference. Getting your carb/s tuned at the same time will aid more in performance and economy, Especially as your intake manifold will be changed as well.

Cheers,

_________________
-Wasabi
1972 Clubman - Daily Driver
1962 850 - EW1 Powered

Extractors are aptly named as they do 'extract' the remains of the exhaust for the cylinders. As said above, you will need to keep the flow, and if it's flowing there will be a bit of suction left when the piston has pushed all the way up.

You can't really go wrong with one of these setups (well, not too wrong anyway). I have LCB extractors on my 998, which isn't ideal, but there is still a noticeable power increase. Just look around and check what's best for your situation (like I didn't).

As I understand it, LCBs are best for big bore or race small bore engines, and the freeflows are better for small bores. LCBs are also a little harder to fit.

The change in exhaust and extractors also made the car much quieter for me, but you hear of mixed responses about this. If you're still running your 30+ year old exhaust, you'll probably come out a little quieter, but with a nicer note too.

thanks for all the replies,
current exhaust is relatively new..got it second hand and figured after rebuilding engine should look at renewing exhaust
engine is a single 1.5carb, 1340cc

Ill let you know this weekend, im chucking on a set of extractors and a sports exhaust on saturday