Holding back when coming onto boost
Turbo Mini Forums

I have a problem where as the engine comes onto boost it just jerks and doesnt produce any power.

Going downhill is less of a problem, it makes boost and pulls ok. going uphill is another matter i have to be very gentle to keep it in the N/A range or it dies.

I have a new reg set to 4psi at idle, pressure increased as i blew on the pipe.
Plenum gasket has correct hole, replaced balance pipe, anti run on and vac advance blocked.

Dashpot level is 1 inch from threads with 3 in 1 oil. Single spring, standard needle.

Im not quite sure where to go from here, i am running megajolt but i am not 100% convinced that the map i have is good. it is the boosted mini one on the autosport library. his setup is similar but with a lower comp ratio. It seems very different from the metro turbo map which i am going to try.

Any ideas?

Are you sure that the part throttle lean off pipe (or as you reffered to it 'balance pipe') is in good condition and has no splits etc?

I ended up blocking this off as I could find no other solution to cure the problem you have described above.

In the 13's at last!.. Just

i had this when i introduced a bleed valve, i ran with an adjustible actuator in the end. as it leaned out like crazy.
what pump are you running, a facet red that did this on a mates car.

edit spelling

Edited by 1972-ANGUS on 19th Apr, 2010.

I put a new piece of pipe on for the part throttle lean off, but it is held on with jubilee clips which dont feel brilliant.
what have you clamped yours with, was there any side effects from blocking it?

I havent fitted my bleed valve yet, its a t2 off a cherry with the standard actuator. Fuel pump is std metro turbo.

Use a decent clip and a shouldered bolt to block it off.

In the 13's at last!.. Just

what afr's are you getting?

ah ive been saving some snapped drills, just need to get some decent clips.

My wideband gives 14.5/15 at idle drops between 10 and 12 when i start to pull away and start spooling, then as it starts to jerk i saw it go upto 19 when i first tried driving it.
if i dip the throttle as it starts to lean it goes richer again and i can gradually bulid up momentum

Blocked hole in carb to plenum gasket? The one that pressurises them fuel bowl?

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

Find a basic map off here for your megajolt, and get it running correctly. Then monitor your afrs as you are driving. Thus should give you some idea If it's a fuelling or timing issue.

sounds like you need to re-profile the needle to me - if your seeing an AFR of 19 ish then its too lean, there is a great guide to where and what to remove.

Ive blocked the lean off pipe and its a completely different car, now when the turbo kicks in it pulls like crazy and the afr stays down.
I still have a slight flat spot just before it generates boost but im hoping this will be ironed out with a new needle,spring and a session on the rollers
Thanks for your help.