Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Phil]

Like I said, I'm not mechanically minded and I don't get that bit either!

Autos are a pain on a rolling road but not impossible. You won't get such an accurate "power at the crank" figure because the coastdown can only be done in "N" and you don't see most of the losses in the gearbox, but rolling road figures are only really useful as a before and after comparison anyway. TBH, unless he's actually going to tweak the map on the rollers and burn you a custom chip I'd say there's little point in using a rolling road except to generate a figure to brag about down the pub.

Cam change is the best route to more power, with a cjhip as well if you feel inclined. Quite an involved job but can be done in a day no problems.

Ignition and induction system are reckoned to be perfectly adequate as standard.

Kevin

The coast down is done in the same gear, and it creates extremely high transmission losses, thats the problem, when i went on the rollers with Sir Sideways last year we were both getting near 90bhp transmission loss.

The other problem is you cannot lock it in one gear, you need '3rd' to get the magical 1:1 and as soon as you plant the right foot to do the power run it kicks down, and as stated below you have to start again.

The berk at Northampton motorsport was going to pull the fuse for the gear box to stop this!!  

[Kevin Wood]

The 3.0 cams will work with the 2.5 engine management but you'll obviously get more out of them if you chip it too, as the maps in the 2.5 will be to suit the milder cams.

I'd expect the idle quality to degrade a little and perhaps for the fuel consumption to increase a tad.

Obviously, which you're there, you should clean the breathers, change the cam cover gaskets, camshaft oil seals, cam belt and tensioners if it's anywhere near due, as that all has to come off. Probably a good time to change the plugs if they're due too.

Kevin

Idle seems to be equally as good and fuel economy seems to be down to the right foot!

There is nothing wild about the 3.0 cams!

Just re-iterating ClarCE's findings. More temptation for the right foot probably doesn't help fuel economy. After all, you need to "test" any upgrades!

Kevin

[al and omega]

Hi there, looking at what everyones put all seems fine for what your looking for i've done nearly everything to the engine i'e gas flowed heads, cams, lightweight flywheel clutch, exhaust etc, the 1 st thing i did after making sure the engine/car was up to it were magnecore ignition leads 8.5mm (the red ones) Ngk irridium spark plugs and an uprated fuel pressure regultor from 3bar to 4bar. i did these jobs whilst doing the cam cover gaskets, its a relativly straight forward job and definatley made the car more responsive. Further mods like a free flow air filter and exhaust etc came later but try the leads, spark plugs and fuel regulator 1st a see what you think, if happy just carry on from there hope that helps a bit!

[Kevin Wood]

Like I said, I'm not mechanically minded and I don't get that bit either!

Autos are a pain on a rolling road but not impossible. You won't get such an accurate "power at the crank" figure because the coastdown can only be done in "N" and you don't see most of the losses in the gearbox, but rolling road figures are only really useful as a before and after comparison anyway. TBH, unless he's actually going to tweak the map on the rollers and burn you a custom chip I'd say there's little point in using a rolling road except to generate a figure to brag about down the pub.

Cam change is the best route to more power, with a cjhip as well if you feel inclined. Quite an involved job but can be done in a day no problems.

Ignition and induction system are reckoned to be perfectly adequate as standard.

Kevin

The coast down is done in the same gear, and it creates extremely high transmission losses, thats the problem, when i went on the rollers with Sir Sideways last year we were both getting near 90bhp transmission loss.

The other problem is you cannot lock it in one gear, you need '3rd' to get the magical 1:1 and as soon as you plant the right foot to do the power run it kicks down, and as stated below you have to start again.

The berk at Northampton motorsport was going to pull the fuse for the gear box to stop this!!  

That's right. Coast down in gear and you've got engine braking and some porridge-stirring in the torque converter to contend with so the losses will be high. Coast down in "N" and very little of the gearbox is turning. You might as well just look at the "at the wheels" figure. After all, the important thing is that you get some idea if you are improving matters or not. Relative measurements don't really need accurate compensation.

With a manual box, of course, you can just declutch at the top of the run and all of the drivetrain continues to spin during the coastdown. You can get a very accurate power at the crank measurement with care.

You should be able to get as near as damn it to full throttle before kickdown, especially at higher RPM. Not fun when they kick down, though especially when they were close to climbing out of the rollers beforehand!


Kevin