OH MY GOD! WORSE THAN A DIESEL!
Turbo Mini Forums

Lads,

This carb is killing me! What the heck is happening here!!!
Look at this pic from the drags



It went well on the night but not as good as it should have - ran a 16.1 1/4 mile.
I put it down to the rev limiter being at 6000rpm

Graham Russell just called me (he saw the pics before me) and said what the hell has happened or what have you done??
Its worse than a deisel!!

That A/F on launch must me like 5:1 :S !!!

Its ridiculous!

So, the A/F before the drags was approx the following
on boost 13.5:1
off boost 11-12:1



Ideas so far that I am thinking of
1. Could be that the choke seal is shot and dumping in raw fuel (you can actually smell it now, the sick smelling raw undleaded fuel)
2. Presurising fuel bowl - ie/ I know its meant to be boost + 3psi but it might be alot more...

Any other ideas why it would blow so much smoke? Its on launch AND during the run.
Sometimes when I start it, it will backfire through the carb and not kick over but then I kick it over and smoke puffs out.

Because of the Megajolt and the coil packs - I think its still running because the ignition is strong - if I had a coil + dizzy I think it wouldnt run at all :S

Help!

Pete

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

One thing that may cause it to run very rich under full throttle would be the carb dashpot piston sticking.

It would increase the air velocity over the bridge and create a high negative pressure that would pull fuel out of the bowl.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Hi
Choke seals could be a favourite here...
Cheers
Gavin :)

VEMs Authorised Installer / Re-seller. K head kits now available!

WB/EGT gauges. Click here for customers write-up

Visit www.doyouneedabrain.co.uk

My Mini build diary

Im going for choke seals too.

Edited by matty on 20th Oct, 2008.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

if you are not sure about fuel pressure I guess it would be rather easy to check that first to be sure...

Like the others have said do the choke seals and check that the piston is freely moving in the carb, Could also check to make sure the needle valve is sealing. What wheels is the mini running in the other lane they look rather large!

just overhaul the carb, probably could do with it anyway.

no longer a series, but still 1.3 turbo.

Ok, looks like we have worked it out - watching the video and more pictures it blows when I hit the rev limiter.

So its the extra fuel being dumped that causes the smoke...

Hrm...

Pete

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

CORRECT! ... Dump the rev limiter and use you own judgement!... a tad over 6k and change

I sat down with Graham and he started writing some figures and charts and we worked out I was only in peak power (ie 16psi) for a VERY short time and then due to rev limiter dropping back into very low RPM (close to off cam and before spool) so we have ditched rev limit, just need to test her out.

Will go over there on Sat to tinker a bit more, triple check A/F and possibly mess with needles and throw her on the dyno.

Without a doubt it should have seen much quicker 1/4 mile times...

Pete

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

your fuelings way out of line

your on the right track