problem with mixture(i think)
Turbo Mini Forums

I have a problem with the tune of my car i seem to have a miss fire on cruse at between 3500 and 4000 rpm right where i need to be to cruse at between 60 and 70mph what the problem is is that at this speed and rpm the turbo is spooling up this is causing problems to get the mixture correct. Everywhere else the mixture is perfect and the car runs a dream but try sitting at between 60 and 70 on the motorway and it will pop and miss


The current setup is as follows:

Med 1293cc engine
1.5 rockers
T3 cam
T2 turbo on mirage manifolds 12psi boost
Ford rs intercooler
Metro turbo dizzy

One idea I have is that could the part throttle lean off be causing the issue and would removing it help?

Any suggestions as to what I can do to fix this issue

"Tuning should be a compromise between what is possible and what is necessary"

10)Thou shalt always quest for more power

what do you mean by t3 cam

I think he means a morspeed t3 cam?

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


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Hi,
What's the inlet air temp?
Carb may be icing up try covering the I/C see if it improves.
Cheers
Gavin :)

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It'e be the MED T3 if he has the MED bottom end, that's basically an Avonbar PH2.

Def not icing (id say) I had it in a temperature controlled dino and it still did it at the given rev and speed it is only when it is on part or light throttle.


However this morning it was worse with the cold weather. My reasoning behind this is that as the air is colder and therefore denser it will make the car run leaner and if at this point it is to lean already it would be worse (correct me if I’m wrong)


yes it is the MED T3 cam

Edited by turbominij on 4th Oct, 2008.

"Tuning should be a compromise between what is possible and what is necessary"

10)Thou shalt always quest for more power

have you the part lean off pipe connected up? if so you could try cutting it in half and blocking each end up see if it improves.

133.5 bhp 123 lb torque 116mph @6640rpm 9.5psi
Shakespear RWYB 14.995 91.83mph

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Do you guys have any trick setups for this, any with ease fitment of the auld "t" piece. (chopin the lean off pipe, which i take is the carb to manifold loopy bit of pipe)

before you block them off mate and possible disrupt the needle/set-up, as if it still has the lean-off pipe on it will have been set-up to incorporate this, put a new peice of pipe on. There only has to be slight pin pricks in this pipe and it will send you chasing things.

is it the original shiney pipe? if so def change it. if not change it anyway and see if there is any difference.

is it the original shiney pipe? if so def change it. if not change it anyway and see if there is any difference.[/quote]in in

Put in new pipe, no difference.
However, within the next week, i am sorting a narrow band lambda. that should help matters!

Not to highjack the other chaps threah, sorry

regards
Colin

1972-ANGUS = highjacker


hi yes the lean of pipe is still connected and yes it is still the shiney one and is brand new as is the rest of the carb (well now 5 months old)

ok i will try a new bit of pipe worth a shot for the sake of £1

i had thought about running a solonoid connected to a switch for cruse on the moterway so when i want to cruse i hit the switch seeing as the mixture is perfect the rest of the time that way around town i would beable to bennifit from the part throttle lean off (only an idea dont no if will work or there is any point)

will give it a shot with the lean off pope blocked off
and with a new pipe

Edited by turbominij on 5th Oct, 2008.

"Tuning should be a compromise between what is possible and what is necessary"

10)Thou shalt always quest for more power

Yeah, thats a good idea and should work perfectly, you just have to remember to switch it if you want to accelerate on boost.

133.5 bhp 123 lb torque 116mph @6640rpm 9.5psi
Shakespear RWYB 14.995 91.83mph