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[JamesV6CDX]

has anyone ever put a car on a dyno before and after 3.0litre cams been fitted? i`ve always been dubious about the power gains from just fitting cams, cant see how they can bring the power up so close to the 3.0litre engine which already has those cams fitted!

id be interested on that as well. i dont understand how putting 3.0 cams in the 2.5 will give good gains. the 3.0 will always have more torque and bhp is rpm x torque so how can the 2.5 get to similar power to the 3.0  :-?

More valve lift....

[Marks DTM Calib]

has anyone ever put a car on a dyno before and after 3.0litre cams been fitted? i`ve always been dubious about the power gains from just fitting cams, cant see how they can bring the power up so close to the 3.0litre engine which already has those cams fitted!

id be interested on that as well. i dont understand how putting 3.0 cams in the 2.5 will give good gains. the 3.0 will always have more torque and bhp is rpm x torque so how can the 2.5 get to similar power to the 3.0  :-?

Bhp = (torque x revs)/5252.....if you want more bhp, juts move the existing torque further up the rev range (exactly what motor bike and F1 engines do).

The cams do work and there are dyno plots around to prove it, its more popular on Vectras and Cav/Calibras though.

The cams offer extra lift and longer duration......I suspect that the 2.5 might have been slightly throttled to give better low end torque and to make sure there was a decent differential between teh 2.5 and 3.0.

And as already said, this is exactly what was done to the 190bhp Vectras......

[Arebee]

Bhp = (torque x revs)/5252.....if you want more bhp, juts move the existing torque further up the rev range (exactly what motor bike and F1 engines do).

The cams do work and there are dyno plots around to prove it, its more popular on Vectras and Cav/Calibras though.

The cams offer extra lift and longer duration......I suspect that the 2.5 might have been slightly throttled to give better low end torque and to make sure there was a decent differential between teh 2.5 and 3.0.

And as already said, this is exactly what was done to the 190bhp Vectras......

Would this be achieved best by chipping the car ??  i have some sports cats and an induction kit on order and am looking to have it chipped anyway to allow it to run to its best capabilitys so could incorporate it all in one go ??

Anyone know of a really good place in the south west that do chips, re-mapping etc...

[Kevin Wood]

Would this be achieved best by chipping the car ??

It's the cams that determine how the engine breathes and it's how the engine breathes that determines where it makes the torque. The chip / ECU is just there to pour the right amount of fuel in and set the ignition timing so it's the cam change that'll make the most difference.

Certainly change the cams before you get it remapped or you'll have to start again. The rest of the induction / exhaust system is not a bottleneck on the 3.0 (save for the exhaust manifold which isn't great) so it will be less so on a 2.5.

I suspect that the 2.5 might have been slightly throttled to give better low end torque and to make sure there was a decent differential between teh 2.5 and 3.0

May well have had a worthwhile effect on fuel economy on the 2.5 too. Milder cams will give better intake velocity leading to more efficient fuel atomisation and combustion.

Kevin

[JamesV6CDX]

May well have had a worthwhile effect on fuel economy on the 2.5 too. Milder cams will give better intake velocity leading to more efficient fuel atomisation and combustion.

Kevin

Does that mean my fuel efficiency is going to go to the Dogs, once I fit my 3.0 cams?