Tuning Improve 1.2 16 V engine

[MikeSalt]

It seems very restrictive, almost impossible to do any modifications. If you are allowed to use induction, get a GSR kit from OldSchool. Most of the competitors will never have heard of GSR and will end up running inferior induction kits such as K&N.

Being that modifications to the engine are not permitted, have you considered swapping the engine? Fiat engines are known to have a variation of a few bhp as they leave the factory. If you could dyno-run a few stock engines and find the most powerful, that will give you an advantage. Expensive option though.

 

[nedge2k]

you might also consider blueprinting the engine for those extra horses

 

[mmelo]

Do you know if the injectors IWP043 works in Punto mk I 1.2 16V? Do you know what are the original ones?

 

[fingers99]

IWP043 are off a Ducati 900 Monster. They'll fit, they'll fire. Without a remap I suspect you'll get monumental overfuelling.

 

[mmelo]

Now I'm think to improve the brake capacity of the car. I notice the car has a diagonal split brake system. Can any way explain me how the pressure is regulate between in same circuit in front and rear ? How a system like this can guarantee the front pressure are the same in both disks?

I'm thinking to install a brake bias (AP with two inlets and outlets) and also change the arrange of the connection put the front in just one circuit and the rear in the other with the brake bias. Should this setup improve the braking of the car. This tandem master cylinder already have, somehow, a way to controlling the pressure that goes to the front and rear?

Any one with experience can help me?

Regards,

MM.

 

[DaveMcT]

The best option is twin master cylinders with an adjustable balance bar. Simply re arranging the existing master cylinders will not work. They work in parallel so both pumps operate all four brakes. The hydraulic (pumping) ratio will be wrong if you simply reorganise the pipes.

Your cheapest option is an adjustable twin circuit bias valve that you install within the driver's reach so he can alter how much force goes to the rear brakes.

 

[mmelo]

Is not allowed, we must used the same brake system circuit. I would like to know how the master cylinder reduce the pressure for the rear wheels since it's a split circuit.

I will used higher friction pads, so I think I will install the bios valve (AP for split master cylinder) to the front brakes because it seems more tencency to lock these wheels, but everything I read normally they install it for the rear which should be the one to reduce pressure to avoid locking.

What do you think?

Regards,

MM.

 

[DaveMcT]

It probably wont work very well doing that because too much fluid will get pushed through. This makes the brakes feel "wooden* - not enough pedal travel. Race pads make brakes even more on/off.

One of my bikes had a 15mm master cylinder and brakes were always poor. I fitted a 12mm and the brakes were transformed. More "leverage" and more brake lever travel so a better feel.

Putting 2 brakes on a circuit designed for 4 brakes will be going in the wrong direction.

 

[mmelo]

It probably wont work very well doing that because too much fluid will get pushed through. This makes the brakes feel "wooden* - not enough pedal travel. Race pads make brakes even more on/off.

One of my bikes had a 15mm master cylinder and brakes were always poor. I fitted a 12mm and the brakes were transformed. More "leverage" and more brake lever travel so a better feel.

Putting 2 brakes on a circuit designed for 4 brakes will be going in the wrong direction.

Sorry but I didn't understood very well you answer. My idea is to used exactly the same brake circuit but using a bios valve. My question is, should it be install in lines that goes to the rear or in the lines that goes to the front disk? Because it seems the front ones have more tendency to block and I expect even worst with high friciton pads.

Regards,

MM.

 

[DaveMcT]

Always put the pressure limiter into the rear circuit. Just be careful to avoid 2x the fluid being pumped into the front brakes. The pedal will feel solid and have no power.

 

[mmelo]

Always put the pressure limiter into the rear circuit. Just be careful to avoid 2x the fluid being pumped into the front brakes. The pedal will feel solid and have no power.

What is a little bit complicate to understand is with a split master cylinder how the front pressure in brakes are equal or in the rear because it work in X (Front Right - Left Rear; Front Left - Right Rear). I think these systems are only for security proposes since at least 3 brakes in work in case one of the circuits will out of order, but have a worst performance than a convention in which one circuit to feed the front and other to the rear.

Regards,

MM.

 

[arc]

Do you know if the injectors IWP043 works in Punto mk I 1.2 16V? Do you know what are the original ones?

if you fit a fuel rail from a brava 1242 16v, then you can fit the injectors from a 1.4 16v stilo, panda, 500, 500abarth, tjet etc.

 

[MikeSalt]

As for the brakes, you are a bit stuck if you have to stick to the diagonally coupled system. In your current system, the master cylinder is actually two pistons stacked together in the same bore. This ensures consistent pressure between the circuits, but it is designed such that if one circuit leaks, the pistons actually push on each other to maintain the force in the other circuit. In these systems, there is a pressure reducing valve on both circuits to control the rear brake pressure.

In order to adjust the front-rear bias on a diagonally-split system, you need two variable pressure reducing valves. And these would have to be set independently (but set to be balanced left to right).

 

[mmelo]

As for the brakes, you are a bit stuck if you have to stick to the diagonally coupled system. In your current system, the master cylinder is actually two pistons stacked together in the same bore. This ensures consistent pressure between the circuits, but it is designed such that if one circuit leaks, the pistons actually push on each other to maintain the force in the other circuit. In these systems, there is a pressure reducing valve on both circuits to control the rear brake pressure.

In order to adjust the front-rear bias on a diagonally-split system, you need two variable pressure reducing valves. And these would have to be set independently (but set to be balanced left to right).

The AP is selling a bios valve (CP4550-1) for split system. But if a install it to the rear wheels I would like to take out the reducing valve of the main cylinder otherwise I will only reduce even more the rear pressure. It is possible?

Note with hight friction pads the car have tendency to block the front wheels not the rear ones.

Regards,

MM.

 

[MikeSalt]

Yes, you can bypass the load proportioning valve, just make up your own rigid brake hoses to go straight from the master cylinder to the load proportioning valve, rather than through the standard valve (which I think is near the back of the master cylinder, if you don't have ABS)

 

[mmelo]

Yes, you can bypass the load proportioning valve, just make up your own rigid brake hoses to go straight from the master cylinder to the load proportioning valve, rather than through the standard valve (which I think is near the back of the master cylinder, if you don't have ABS)

No


I don´t have abs. So at the exit of the master cylinder all the pressures are equal. Then for the rear there is a pressure reducer which is out of the master cylinder. I thought it was internally done this reduction, but like this is easier. I just can take out the pressure reducer and instal the bios valve.

Regards,

MM.

 

[MikeSalt]

That's right

 

[mmelo]

And I think where they are, right near the rear wheels.

Good. In this case I think I also change the master cylinder configuration. The main cylinder to the front brakes and the secondary one to the rear. With this conf. I think the pressures will be more equilibrate.

Another question anyone knows if there is high performance ignition coils available for the car? If they are exterior equal better.

Regards,

MM.

 

[DaveMcT]

The issue is that you are more likely to over brake the rear wheels than the fronts. which is why it needs a bias or pressure reducing valve.

But if you try to run one circuit to the front and the other to the rear you will have problems with the hydraulic ratios being wrong and the bias valve will not work properly - the excess pressure has to go somewhere. Normally its taken by the fronts with just enough allowed through to the rears so they dont lock.

You will need an adjustable valve so it can be changed according to the race circuit. Some need more rear bias than others.

 

[MikeSalt]

And I think where they are, right near the rear wheels.

EDIT: Previous information source was wrong

Do you have a mk1 Punto? If so, I think you are referring to the thing that looks like a valve on the subframe, with two metal pipes going into it. According to ePER, that is the brake pressure reducing valve. On higher models, this has a link between it and the anti-roll bar link that adjusts the pressure proportionally to the load on the back wheels.