Bf Mk2 06/06 Or Fg Motor

[Brendan XR6-T]

I was going to see c v tomorrow to get it checked out again but I changed it for another day plan is to upsize from 42lb injectors to the 60's and get a walbro I figure might aswell make the visit worthwhile. Hoping to get between 320-350rwkw I know the bottom end will be abit of grenade but I'll cross that bridge when I get there.

Hey matty your right with 3rd to 4th when on the rollers provided all the gear ratios have been set in properly so I'm told. I asked him y he dyno'd it in 3rd but he told me he accidentally wrote 3rd in and the numbers on the top left are just a reference.

I don't know accidentally this and that I'm lookin forward to seeing cv performance they have a winter special on for there tunes which should save a couple of pennies...

[mattyb]

350kw in a BF should be pretty safe... that's about the norm. Keep us posted as to how you go.

[Panda Eyes]

320kw @ the rollers in third is the same as 320kw at the rollers in 4th... The power is being read at the back wheels. the car is still putting 320kw to the ground only some put the 330down while in 3rd gear, and others get it down in 4th gear.

most dyno runs are done in 3rd as that is closest to a 1:1 ratio of engine speed to back wheel speed. less chance of discrepancy.

changes in dyno readings can just be ambient differences on the day. my 320rwkw reading went down to 308rwkw when getting a base reading for the next mods aboutto be done. same dyno, same operator.

[mattyb]

what I was saying is that the dyno reads what is being put out at the wheels... as the wheels spin. my 350 at the wheels, in third is just as true as the next guys 350 in 4th, as they are both measures at the wheels... the only difference would be in torque delivery. But me and brendan are running the ZF6 speed, so I'm pretty sure that 4th seems to be the norm, although my tuner uses 3rd and his tunes have been unbelievable.

[Brendan XR6-T]

Like you said matty the torque went up but he upped the boost to from 14 to 16psi but I dont think its 16 all the way through he had to back something off up the top end coz he was getting alot of pinging so as you can c from the dyno sheets it makes more power and torque up to about 3500-4000rpm but tapers back down. He reckons its just not getting ennough fuel and theres definetly more in it but he couldnt get enough fuel. I actually printed one dyno sheet on top of the other today and it makes it alot easier to make out I'll post it up later. Looking forward to bigger squiters pump and cv tune ill let you guys know how everything went in my next post when it is all done.

Thanks for all the reply guys Brendan

[ratter]

We have found the ZF will show more power when run in 3rd gear as opposed to 4th, it shows more so in lower power cars. I spoke to my dyno supplier about this and he also belives that the power should remain constant no matter what gear is used but torque will be higher, but when I explained my findings the best outcome he could come up with is the different gears are producing differentr wheel speeds for the same given rpm, with this higher wheel speed comes more windage loss, a lower power car will be affected more so than a higher power car due to the higher power car being able to turn the wheels easier so it does not show the loss as much. Roller windage loss is accounted for in the dyno's calculations but it can not take into account the wheel windage loss.