General Punto 75 Engine tuning

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General Punto 75 Engine tuning

StoneNewt

Scandinavian Passion....
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Any estimates on how much power a 75 would produce with this little lot?
* 268º Cam
* BMC CDA induction kit
* Custom ECU remap
* Supersprint Exhaust manifold, decat/centre section & back box

I'm aiming for about ~100bhp when finished, I'm just wondering about how far will that get me?
 
A fella on in another section races a punto 75, and hes had to spend over £1000 alone on the ECU, as he said the standard one couldnt produce what he wanted, or it couldnt be mapped. In fact, here, this is what he sent me when i enquired about the enigne is was using, interestign fella, real good of him to spend the time and reply in such amazing detail to my questions:

Originally Posted by jimbro1000
Quote:
Originally Posted by punto_jr_sx75
Hi, I have a n MPI punto also, just wondered what you've used to get your car over 100bhp? im struggling on paper to find somethign to get it over without a turbo (which i dont want) I would really appreacite your help :)

Thanks

A and R
Jordan



You need a number of factors - first of all you need to overbore a 1242 block and some proper forged pistons which raise the compression ratio. The bottom end needs lightening and balancing to relieve stress and allow the engine to rev. The head needs careful flowing and the inlet valves increased in size. Cam profile will be down to what level of performance you want and whether or not you want to run it in a road car everyday. A race cam is likely to prove hard to live with.

The induction system needs a short trip to the waste bin and replacing with a fabricated manifold to mount throttle bodies. The exhaust also needs throwing away and a properly fabricated tubular manifold fitted instead.

You will need an oil cooler installation with an oil-thermostat as the engine will be struggling to dispose of excess heat. An uprated (preferably aluminium alloy) radiator will assist in the matter.

The engine management is also going to be thrown away and an aftermarket system (I prefer DTA) used as a replacement.

You now have a system that will happily rev with an increase in both capacity and compression ratio. You'll need to run it exclusively on super unleaded unless you are careful *not* to increase the CR too much. Power will be dependent on how much you spend on the above jobs. If you have to do it on the cheap you will likely struggle to get past 100bhp simply because half of the hardware listed above is fairly expensive (expect to pay about £1500 just for the engine management). Even if you only get 100bhp though you will have a lot more torque consistently across the rev range and the car will be much faster than the peak power would suggest.

The engine I've had built for me goes way beyond what I've mentioned above. I do not know all of the details but it has all been very carefully done. The work is very extensive though - not a single component has been left in standard form.

If I wanted to go for a full race configuration the engine would likely be good for about 190bhp but I would have to compromise the engine in several places to achieve it.

The other alternative is to incorporate a nitrous kit but again you need the forged pistons and the lightened, balanced bottom end so it is not necessarily substantially cheaper.

What you do need to avoid is the 16v head - you can get some very impressive performance but it is not cost effective (not that any of it is cheap).

Beyond the engine you will need some reinforcing to prevent the engine ripping itself out of the engine bay. An upper and lower strut brace in the front is essential to this. If you like lots of repair bills you can do without a head stay but if you only want to do the job once you will need a restraint system fabricated and installed. This will prevent the engine rocking in the engine bay under the new higher levels of torque. It isn't a simple modification and I don't have any details of what you will need to do (yet) as this is the last piece of the puzzle for my car. Other cars with 100+bhp all tend to suffer from damage as a result of the engine moving around (in particular the water pipe the runs across the front of the engine).

then he sent after more questions:eek: :

Originally Posted by jimbro1000
Jordan,

I wasn't joking when I said there was a lot of work envolved in getting my engine where it is now - and it still isnt finished. The specification is based around a full race-setup but with concessions to road use. Ironically those concessions have increased the cost rather than decreased it but such is life.

If you are going for a simpler approach to the modifying on one of these engines I would strongly recommend the larger inlet valves as a basic change along with the porting and flowing. You really won't regret it and it will probably have a far greater effect than the camshaft.

The throttle body on the standard manifold is very much just plain dire and a serious limit on what you can hope to achieve. Enlarging it or better still ditching it altogether in favour of a more adaptable device is essential. It will sound much nicer too :)

If you know what size valves you want to use I'm sure we can offer some advice on where to obtain them.

I've had the gearbox on my car quite extensively modified to handle the extra power - and the addition of a handy limited-slip diff to control the delivery. Driveshafts were custom made by a reputable supplier (they provided the driveshafts for my 300bhp race setup).

I only tend to post in the cinq/sei and x1/9 forums simply because those are the cars I have that are of interest here. Once the engine is up and running (might just be today on a long shot) I will be posting up more pictures for sure ;)

:eek: :eek: :eek: :worship:

Hope that helps?

Jordan
 
punto_jr_sx75 said:
Hope that helps?

Jordan
Yes, but kinda not really as most of that I'd worked out already, however from what he's said the route that he's taken is much more 'developed' (& expensive) than I'm really considering.
 
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