Performance on a 2.2 or 2.1 F4R

[Eros]

I´ve read mani threads on increasing engine capacity on the F4R. They say that it reduces the power peak, that means the car´s top speed would be less ? (with a remap and an otherwise standard engine).

After reading the other threads it still unclear to me if it is the same increasing bore and increasing stroke.

 

[Clioman51]

More displacment must be good?

 

[RichMcc]

Hell of a lot of work and cost, it would need to be re-bored, new pistons not to mention labour of removing and stripping and rebuilding the bottom end.
Probably be cheeper to stick ITB's on!

 

[edde]

I´ve read mani threads on increasing engine capacity on the F4R. They say that it reduces the power peak, that means the car´s top speed would be less ? (with a remap and an otherwise standard engine).

After reading the other threads it still unclear to me if it is the same increasing bore and increasing stroke.

If you's looking at bigger Cc engine then its not simple cheap work. But it would assuming normal spec just make the wheole engine more powerful. However since this sort of mod is donw with cma head work ITB's etc then yes it will make a way more powerful engine plus you'd often look at a stronger bottom end for more revs.

Bore is the diameter of the distons the stroke is the amount it moves up and down.

 

[Eros]

I´ve read mani threads on increasing engine capacity on the F4R. They say that it reduces the power peak, that means the car´s top speed would be less ? (with a remap and an otherwise standard engine).

After reading the other threads it still unclear to me if it is the same increasing bore and increasing stroke.

If you's looking at bigger Cc engine then its not simple cheap work. But it would assuming normal spec just make the wheole engine more powerful. However since this sort of mod is donw with cma head work ITB's etc then yes it will make a way more powerful engine plus you'd often look at a stronger bottom end for more revs.

Bore is the diameter of the distons the stroke is the amount it moves up and down.

I know what is each thing, what I´m asking is that if it´s the same to bore or to increase stroke regarding the car´s performance. I think that if you bore it, the engine will be more revy and if you increase stroke it will be more torquey from the bottom.

 

[Batman]

I´ve read mani threads on increasing engine capacity on the F4R. They say that it reduces the power peak, that means the car´s top speed would be less ? (with a remap and an otherwise standard engine).

After reading the other threads it still unclear to me if it is the same increasing bore and increasing stroke.

If you's looking at bigger Cc engine then its not simple cheap work. But it would assuming normal spec just make the wheole engine more powerful. However since this sort of mod is donw with cma head work ITB's etc then yes it will make a way more powerful engine plus you'd often look at a stronger bottom end for more revs.

Bore is the diameter of the distons the stroke is the amount it moves up and down.

god you have alot of posts i'll play catch up

 

[GordonD]

If you's looking at bigger Cc engine then its not simple cheap work. But it would assuming normal spec just make the wheole engine more powerful. However since this sort of mod is donw with cma head work ITB's etc then yes it will make a way more powerful engine plus you'd often look at a stronger bottom end for more revs.

Bore is the diameter of the distons the stroke is the amount it moves up and down.

I know what is each thing, what I´m asking is that if it´s the same to bore or to increase stroke regarding the car´s performance. I think that if you bore it, the engine will be more revy and if you increase stroke it will be more torquey from the bottom.

Increasing the stroke will make the car more torquey at the bottom end - it'll get to a slightly maximum torque and maximum power at slightly lower revs - but may require reducing the maximum revs for an engine that's already as long-stroke as the Renault.

With with increasing the bore its a bit different. An engine designed from the start to be bigger bore and shorter stroke can be made to be more revvy than another that isn't. But if you take an existing engine design and increase the bore it doesn't make it more revvy because you're still breathing through the existing head that necessarily has smallish valves to fit them inside the standard (small) bore size. Increasing the bore size on an existing long-stroke engine will also tend to lower the revs at which maximum power is produced. Unless the head was over-engineered as standard you simply get the point at lower revs where the maximum amount of air the head can flow is reached. You will get more power, but not by as much as you'd think, because that's require everything to be sized up, and the valves and head passages usually can't be.

The difference is that providing you fit lightweight pistons, ones that are no heavier than standard ones, increasing the bore doesn't have any bad effects. But even if you fit lightweight pistons when you increase the stroke you will still have increased piston speeds.

The Corolla 1.8 engine is an interesting example of all this. They have a standard version that revs out to ordinary sorts of revs. But because like the Renault it is already as big in capacity as they could stretch it, and fairly long stroke they had to do something pretty innovative for the high performance version. And they did. They shortened the stroke and removed the cylinders liners to increase the bore to end up with an engine that would rev harder. And because the removal of the liners meant the pistons were running directly in the alloy of the block they changed the alloy they cast it out of to one that contained silicon. And so it still had decent bottom end torque they fitted "intelligent" variable valve timing. And despite all that they ended up with a car that pretty much everyone thought was a dog because it only had as much torque as the standard Corolla, but had more weight, so it was actually slower unless you revved the living bejeezes out of it. But the very same people think its a great engine when it comes in the Lotus, because there the lack of torque is made up for by the car's lower weight.

 

[Eros]

My engine head is a work right know, my idea is to bore it, put forged pistons and taking it maybe to 2.1. With the boring I´m not supposed to loose any top speed right ? maybe gain a little bit ?

 

[Fred@BTM]

i wouldn't bother touching the block, more hassle than its worth

 

[edde]

god you have alot of posts i'll play catch up

Dont you end up with no life.

 

[Eros]

Any idea of the aproximate bhp gains ?

 

[gr1340]

I had a 1975 1275cc (about 75bhp) mini and had it bored to 1340cc. MG Metro head (so I could run unleaded), 1275 GT gearbox, new pistons, valves, piper fast road cams, balanced everything, 2 1/2 inch straight through s/s exhaust and a K&N. It then ran about 100+ bhp and was pretty fast.
I think it cost about 1k for everything but that was with my dad doing the labour and a local place bored the engine block balanced it (they drilled holes in the flywheel - looked cool).
All that bhp for an extra 65cc
I would guess you would be over 200 bhp for a 2.2 but I think it would have more guts to it than just bolting on some mods (exhaust, induction etc).

 

[edde]

Any idea of the aproximate bhp gains ?

Would depends on spec.

 

[RichMcc]

A good set of cams and a remap of the standard ecu would give you comparable gains for a lot less money and effort, the labour on bottom end work would be incredible.

Unless you were going for major engine work including reboring, cams, rods, pistons standalone ecu etc etc for the maximum you could squeeze out of the engine then its not worth touching the bottom end. The same gains could be achieved for a lot less cash and effort than simply reboring a standard lump.

 

[Eros]

My idea is to just bore a little bit and keep the bottom end standard. Maybe some cams to run with just a remap, not standalone ecu. The thing is I´m in Argentina, that sort of work is not so expensive here, and I don´t want to loose traction control (don´t ask why I just like it).
I can get cams but the only ones I can get are very wild (250 bhp to run with ITB and standalone ecu) I don´t want that.