exhaust Q's

Firstly, are you planning to use pre-made bends or weld up your own exhaust?

pfft all being done at home, got a pipe bender to hand as of the weekend :)

Yer average pipe bender 'will' crimp / collapse exhaust pipe on the inside of the bend. Machine mart type hydraulic benders only work with pipe of the thickness you would find in scaffolding etc. Of course, you could be borrowing a mandrel bender - but that's very possibly not the case, yes ?

not too fussed about it being spot on, plenty o sand and a lot of heat, ffs its only a crappy punto so i'm not needing anything near perfection :)

Dry sand remember.

thing is the actual fabrication isnt the question i can mig tig and gas fine :)

its in whats going to happen to the running with the removal of bits.

its a revvy little s**te with all the power above 5k and wondering if a few removed parts will impact on this and maybe make it a bit more useable

Yes if you remove the engine, the power to weight ratio will improve no end

Especially if you stick a Rover V8 in there...

-- JackH

What the *f*ck* is the point?

OEM middle box is 45 quid, rear box 35 quid.

Why f*ck about for the best part of a weekend making something that looks s**te, makes the car run s**te, and *will* mean an MOT fail when the OEM bits are so cheap?

Firstly if its still running the stock cast manifold then 1-2bhp. The only gains from an exhaust point of view is with the manifold. Get a decent 4-2-1 and then worry about whats behind it.

Removing the cat will yield you 1-2bhp at most, 0 at worst. Modern cats are not restrictive. If you do remove it, you must retain the 02 sensor in place, and connected.

Tim..

Get a cheap system from KWIK FIT.

Why?

You will get absolutely *NO* performance increase unless you throw the

1.2litre engine in the nearest bin and fit a much bigger one. Or just buy a faster car.

That will probably slow the car down and make it sound different. But why have a car that sounds great but has rubbish performance.

It will make it go slower! If you can imagine a 1.2punto being any slower than it is before some Barry has tarted it up.

No difference whatsoever. It will just make the car fail the MOT.

Oh dear, I would prescribe some tablets for you to start taking immediately.

You obviously didn't learn much. The biggest money maker now is a market that targets thick people, mainly teenage boy racers. Tell them something will make their crappy little car quicker and they will not only buy it, but believe in it and convince others. Look in any car magazine. The horrific claims of "extra 20BHP" will have the idiots taking bank loans. If they sat back and thought of all the money they wasted, they could have saved and bought a faster car.

I hope you manage to grow out of it soon. If you do want a custom exhaust, I'll sell you one for £3500 that will give you an extra 500BHP, also an air filter that will give you 20BHP and windscreen washer bottle good for another 30mph top-end.

maybe i worded that wrong, i'm not interested in gaining power, just moving it down the rev range somewhat

As long as you don;t go mental on the bore size, it should be OK. Anything over a 2" bore all the way down is going to kill it.

Change the cam then.

If you want more mid range with less top end then the general approach is to increase speed of flow either by fitting straight thru boxes and/or a narrower pipe and/or smoothing out the joins and bends ...but I doubt you'd want a narrower than standard pipe on a 1.2. In the old days on Minis the trick was to remove the centre box but I think that would be for ultimate power not for moving it down the rev range.

As everyone else has pretty much said if you've got a 1.2 punto you're pretty much buggered but if you want to have a play why not try a few things and see what happens?

I'm not sure if Rob's Punto is a "Sporting" or not, if it is, it puts out about 85-90 revvy-l'il-bugger bhp as standard, which is a lot for a

1.2 anyway. I think the fun thing about driving 1.2 Punto Sportings apart from the chuff all body roll and the rediculously short go-kart style steering, is the power delivery. The engine begs for revs, but the car is a PITA to drive for long distances or to sustain any sort of high constant speed.

Personally, I think if Rob really wants more mid range, he should buy a car that has it built in rather than arsing about with the exhaust on his car.

If, as I suspect he just wants to rip a car apart and play with his new pipe bending machine then I think he should just experiment away but I think it will inevitably lead to the car either having the standard exhaust back on, or Rob paying someone to make him up a nice stainless one or something.

We shall see.

(c:

Having a slightly higher backpressure, i.e. more restrictive exhaust may help - might be worth lashing up a slight blockage to see.

Alternatively you could have a look at resonant tuning. The idea behind this is that the exhaust gasses are expelled in pulses of increased pressure, two per engine rev for a 4-cyl. The pulses travel along the exhaust over a short period of time. At the exit of the exhaust, there is a partial reflection of the pressure pulse, which travels back up the pipe. If you can tune the length of the pipe such that the pressure pulse travels down and back in half the time between the pulses, then you actually get _lower_ than atmospheric pressure at the exhaust manifold at the next pulse, so you get both reduced exhaust losses and improved scavenging.

The reflection at the end of the exhaust depends on the pipe diameter - smaller reflects more back up the pipe, so don't get a bigger pipe than absolutely necessary for the peak power you want.

its 2 1/4 bore stock

and yes it is a sporting

its a bloody pita for driving at anything less than 10/10ths

Flog it and buy something more suitable.

You're never going to get much in the way of low down power from a peaky

1.2 16v.