[R555]

Hi Guys,

Something James May said on Top Gear last week got me thinking, he said something along the lines of its not about how power you've got, but how much power you can use... Now I know alot of the newer 2WD hot hatches are coming out with 250 - 300+ BHP but in our FN2's (with a LSD) does anyone know at what limit does power in the FN2 become useless? I remember going out in Tim's CT supercharged car before TDI installed boost by gear and it really was an animal and seemed to struggle to put all the power down.

Would say 250BHP be better than 290BHP?

 

[stoney]

It's not just that imo, its the delivery of power and the torque vs revs gain.

Thats where the Rotrex seems to be so friendly, it's bhp rises uniformly with revs with no sudden torque loading low down, helping grip and wear and tear of valvetrain and geartrain etc.

Boost by gear works on the same principle, keeping the torque down until the ability is there to give it grip.

 

[coste1l]

i think with bbg its all useful maybe not in the first 3gears but above that its all useful surely? i know you are chasing more torque but is that sensible at the expense of traction? i dont know what can be achieved with mapping on a n/a car?

sent from my phone

 

[pablolimey]

It's not just that imo, its the delivery of power and the torque vs revs gain.

Thats where the Rotrex seems to be so friendly, it's bhp rises uniformly with revs with no sudden torque loading low down, helping grip and wear and tear of valvetrain and geartrain etc.

Boost by gear works on the same principle, keeping the torque down until the ability is there to give it grip.

This must be the cleverest forum in the world. I love learning here!

 

[stoney]

Just to add TDIs turbo system seems up there too, Very Flat torque curve right to the limiter

 

[tdi-north]

We have a customer with an EP3 running 600bhp on the road and with the boost by gear it is devastatingly quick as you dont see full power until 5th but each gear has the preset and ramped boost for that gear to maintain traction. Its a very strange feeling when the acceleration gets harder and harder as you go up through the gears!

 

[stoney]

Higher gear faster acceleration lmao

 

[tdi-north]

On the other hand, my car has 380bhp on the wastegate (i need another to drop the boost more) and in the dry, 3rd gear will brake traction and 4th will grip and go but in the wet it brakes traction in 5th when the VTEC and boost comes in.

As soon as i get another WG on there i can drop the boost to 3/4 psi for the first few gears and properly utilise the BBG, its night and day difference.

Ben

 

[Dave84]

How does the traction of a charged fn2 compair to a focus rs?

 

[Relic]

Celtic tuning done a piece comparing various remapped cars they did.
They did a modded civic turbo diesel version with 228bhp 336 lb/ft.
http://www.celtictuning.co.uk/pages/publications/Honda_Civic_2.2%20iCTDi%20Stage%203.pdf
But its the torque that was the main thing.
It had similar acceleration times as remapped st as the ST simpy could not put the power down with 285bhp 294 lb/ft.
http://www.celtictuning.co.uk/pages/publications/Ford_Focus_ST 2.5 Turbo 221bhp.pdf
BBG is excellent...its a shame we cant go the whole hog and have 100% mapping by gear too for things like ramair.
[note 0-anything upto 70]

2nd gear in mine too much throttle simply brakes the tyres away.
In the wet 3rd and sometimes 4th gear will go too.
Perhaps we need wet and dry maps

 

[coste1l]

i dont have the same traction issues mick? in a straight line or out of a corner?

 

[Relic]

Straight line
Corners ??? anic:..I sooooooooooooooo need FRS and Eibachs .... ooh and LSD

Thats the differnce between a smooth progressive power curve with peak torque at 2800rpm
and an aggressive map with peak torque at 2000rpm and 3250rpm

Celtic hit 316 lb ft at 2650rpm
You hit peak at 2800
I hit 316 at 2000

...well...I did in june 2011 anyway.

 

[Dave84]

How does the traction of a charged fn2 compair to a focus rs?

anyone?

 

[pulpmelon_r]

^As above, torque is the factor that gets a fwd car out of shape.

regarding focus rs / charged fn2

The focus was designed for that power level the civic was not, you will need supporting chassis mods eg LSD

 

[civi08]

You'd need to find someone who's driven both. Fat4y might be the best guy to speak to, however with the RS's revoknuckle technology i imagine it holds the road and manages to put the power down better than a supercharged fn

 

[stoney]

I've driven a modified RS and it surprised me how well it put it's power down, but as said its designed with more power from the factory plus bigger and wider wheels etc.

 

[coste1l]

Straight line
Corners ??? anic:..I sooooooooooooooo need FRS and Eibachs .... ooh and LSD

Thats the differnce between a smooth progressive power curve with peak torque at 2800rpm
and an aggressive map with peak torque at 2000rpm and 3250rpm

Celtic hit 316 lb ft at 2650rpm
You hit peak at 2800
I hit 316 at 2000

...well...I did in june 2011 anyway.

ahh!

sent from my phone

 

[Dave84]

You'd need to find someone who's driven both. Fat4y might be the best guy to speak to, however with the RS's revoknuckle technology i imagine it holds the road and manages to put the power down better than a supercharged fn

Just checked you build thread mate, car looks amazing with the bonnet and wing, not to sure about the wheels IMO.

Does it handle fairly well compared to a standard FN2 with the LSD?

 

[civi08]

Just checked you build thread mate, car looks amazing with the bonnet and wing, not to sure about the wheels IMO.

Does it handle fairly well compared to a standard FN2 with the LSD?

thanks, it handles really well with the LSD, also eibach springs and FRS. its a dream to drive. You just have to not get carried away in gears 1-3 by flooring it or you'll be leaving rubber on the road, i need to sort boost by gear then it'll be better still