07-03-2012, 12:57 PM
In driving them you would feel differently, but technically, you will get the biggest boost in power all over the rev range with a stage 1 tune, and all for the lowest outlay in money.
A good way to look at it is this:
Motorway cruising at 60mph in 5th gear, about 2750rpm iirc. At 2750rpm on a standard engine you have about 70bhp at the wheels.
You have about 12bhp loss due to the aero dynamics, you have about 3bhp from tyre drag, so about 15bhp losses.
That means at 60mph in 5th gear on the motorway, you have about 55bhp left to accelerate you forwards.
Once you have remapped the car to stage 1 (basic tune is the best thing to call it), you have more like 90bhp at the wheels at 2750rpm, so with those same losses taken away, you have 75bhp left to accelerate you forwards.
So 75bhp from 55bhp is a 35% improvement in power, which means 35% more acceleration, which is quite a lot really!
And that is the worst case scenario because it's near peak power of the standard car.
The remap to stage 1 adds more power at higher rpm, so in 4th gear at 3000-4000rpm, you have about 50% more acceleration than you do as standard, which is loads more!
So in the worst case, you have about 30% more acceleration, in the best case you have about 60% more acceleration, so lets say on average you will feel it to be about 45% more accelerative!
A stage 2 tune, with the associated intercooler and all the other mechanical work, doesn't offer the same gains from the stage 1 tune. It's close, but when you look at bang per pound, it's nowhere near.
An intercooled HDi though is getting into the realms of a genuinely nippy road car, and they are well worth having a go with! I wish I'd never sold mine now
Dave
A good way to look at it is this:
Motorway cruising at 60mph in 5th gear, about 2750rpm iirc. At 2750rpm on a standard engine you have about 70bhp at the wheels.
You have about 12bhp loss due to the aero dynamics, you have about 3bhp from tyre drag, so about 15bhp losses.
That means at 60mph in 5th gear on the motorway, you have about 55bhp left to accelerate you forwards.
Once you have remapped the car to stage 1 (basic tune is the best thing to call it), you have more like 90bhp at the wheels at 2750rpm, so with those same losses taken away, you have 75bhp left to accelerate you forwards.
So 75bhp from 55bhp is a 35% improvement in power, which means 35% more acceleration, which is quite a lot really!
And that is the worst case scenario because it's near peak power of the standard car.
The remap to stage 1 adds more power at higher rpm, so in 4th gear at 3000-4000rpm, you have about 50% more acceleration than you do as standard, which is loads more!
So in the worst case, you have about 30% more acceleration, in the best case you have about 60% more acceleration, so lets say on average you will feel it to be about 45% more accelerative!
A stage 2 tune, with the associated intercooler and all the other mechanical work, doesn't offer the same gains from the stage 1 tune. It's close, but when you look at bang per pound, it's nowhere near.
An intercooled HDi though is getting into the realms of a genuinely nippy road car, and they are well worth having a go with! I wish I'd never sold mine now
Dave