pre-avon help needed, trying to figure out my RR graph.
Turbo Mini Forums

had my car on the rollers today so i could get it checked over and up the boost to 15psi for avon but things haven't turned out too well really.

The car went in with around 110 banana's @ 5700rpm but after 4k rpm the torque just dropped right off which i've noticed while driving it. You got a bit of hesitation as it was about to boost then a big pull as it came on boost then it just felt flat after that.

After changing the needle cos it was leaning out top end and winding it up to 15psi its all gone a bit weird tbh and i cant work out if its down to fuelling, timing or maybe even something like cam timing. Now theres a big drop in power as it comes on boost then at 3300rpm it goes mental and pulls up to 135 banana's and 165lb/ft, but then at 4300 rpm both the hp and torque drop right off whereas before it was just the torque.

Here's the graphs from before and after, see what you make of em and if anyone could give me some advice it'd be appreciated. I'm thinking it's gotta be something major like cam timing being out maybe? cos when you floor it while cruising there's a lot of hesitation and lots of popping/banging and sounds like its firing back through the carb then it gets to about 10psi and takes off spinning the wheels etc...

before
http://img.photobucket.com/albums/v175/bud666/RRbefore.jpg

after
http://img.photobucket.com/albums/v175/bud666/RRafter.jpg


Anyone got any suggestions on what to look for? I'm tempted to get up early and attempt to check my cam timing. Or am i just being a gobshite and its all down to setup?

Cheers, Nick :)

hc to co ratio is a good way of indicating cam timing, i.e if the hc's are high and the co is low then your cam timing maybe out by a significant amount.

only other thing i can think of is ignition timing (if the fueling is surficient at the top end)

maybe best to wait for the more experianced lads

I've seen the future and tbh its Pie

bud , the poppng nd banging sounds like a lean patch , is yuor fuel pressure regulator keeping the fp above boost at that point ? the torque its putting out at 4500 seems good and would not suggest bad cam timing ,do you know what the mixture was on the rollers after 4500 ? ,do you have points or electronic dizzy ,have you closed the plugs up to say 20 thou to eliminate spark faliure and tried that ?
regards robert.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

cheers chaps, i'll check out the fuel pressure later and make sure its all ok and rising with boost.

I'm running a megajolt robert, got a new set of plugs here to drop in aswell and see if they change anything.

Just got back from work and had the opportunity to look at the graphs....

tbh wtf! where did you take it? Did you alter ignition timing? Did they alter the needle?

I've seen the future and tbh its Pie

after you have tried out all the above budd

my suggestions would be............

fueling, fueling,

advance curv on the megajolt
ask nic for his 18 psi boostmap

check the plug rating also as your lifting the boost champion N7YC are agood start

and the RR sesion its got to be peter baldwins

Edit:good luck

Edited by BENROSS on 14th Jul, 2006.