ausmini :: View topic - Hesitation on part throttle acceleration

Not enough throttle? :roll:

What springs do you have in your SUs? Possibly a little too stiff?

slinkey inc wrote:

Not enough throttle? :roll:

What springs do you have in your SUs? Possibly a little too stiff?

Using the Cooper s springs, red I think. Slightly stiffer than the cooper Springs. Tried the blue ones, just didn't feel right, let the motor hunt a bit at constant revs. (very marginal hunting, I am picky).

There are times when i like to drive without using full throttle...... :roll:

I know you said refurbished SU's, did that include the throttle shaft bushes?

Air sneaking in there could be the cause.

don't forget change a spring change the Needle
also a reminder Check you fuel filter also

Author:	Matt68 [ Fri Aug 10, 2007 3:47 pm ]
Post subject:	Hesitation on part throttle acceleration
Hi, I was wondering if anyone has any bright ideas about why i have 'hesitation' or an unwillingness to go faster at slow acceleration (part throttle, low load). If I nail it it spins up to 6000rpm (my self imposed limit) very happily, no worries at all. Basically, it accelerates well under heavy load, full throttle conditions, not quite so happy just creeping up. What are the basic things to consider about this, where would the problem be? 1310cc Twin HS2 SUs, reconditioned, matched, in VGC as far as I can tell Maniflow inlet manifold and LCB "AH2" needles ('rich' cooper s needles) 20w monograde oil in dashpots, correct level ITG air filter on KC's ultimate filtration kit (stub stacks) Fuel regulator regulating pressure to a steady 2.5PSI Cheers Matt

Author:	Blokeinamoke [ Fri Aug 10, 2007 4:53 pm ]
Post subject:
overfueling or plug gap or coil

Author:	slinkey inc [ Fri Aug 10, 2007 5:03 pm ]
Post subject:
Not enough throttle? What springs do you have in your SUs? Possibly a little too stiff?

Author:	Matt68 [ Fri Aug 10, 2007 5:04 pm ]
Post subject:
Thanks BIAM, Overfuelling i will investigate, would it be the kind of thing caused by incorrect needle profile, or would it have to be 'bigger' such as needle valve, flooding essentially? The coil is a new GT40T, may be at fault, might have to sub in another, see if it changes anyhting. Plug gap is 35 thou I think, I also use a 123 ignition dizzy, so plenty of spark available. Keep the ideas coming people!! Matt

Author:	Matt68 [ Fri Aug 10, 2007 5:09 pm ]
Post subject:
slinkey inc wrote: Not enough throttle? What springs do you have in your SUs? Possibly a little too stiff? Using the Cooper s springs, red I think. Slightly stiffer than the cooper Springs. Tried the blue ones, just didn't feel right, let the motor hunt a bit at constant revs. (very marginal hunting, I am picky). There are times when i like to drive without using full throttle......

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Author:	hbr [ Fri Aug 10, 2007 5:33 pm ]
Post subject:
I know you said refurbished SU's, did that include the throttle shaft bushes? Air sneaking in there could be the cause.

Author:	slinkey inc [ Fri Aug 10, 2007 10:45 pm ]
Post subject:
Matt68 wrote: slinkey inc wrote: Not enough throttle? What springs do you have in your SUs? Possibly a little too stiff? Using the Cooper s springs, red I think. Slightly stiffer than the cooper Springs. Tried the blue ones, just didn't feel right, let the motor hunt a bit at constant revs. (very marginal hunting, I am picky). There are times when i like to drive without using full throttle...... Hmm, doesn't sound like springs then, Cooper S would be the correct ones.

Author:	gafmo [ Fri Aug 10, 2007 10:59 pm ]
Post subject:
don't forget change a spring change the Needle also a reminder Check you fuel filter also

Author:	Matt68 [ Sat Aug 11, 2007 12:49 am ]
Post subject:
hbr wrote: I know you said refurbished SU's, did that include the throttle shaft bushes? Air sneaking in there could be the cause. Hi Yep, brand new shafts, which removed 100% of the 'slop' in the shafts. Good idea tho! I've also checked manifold to head mounting etc, no leaks. Matt

Author:	Matt68 [ Sat Aug 11, 2007 12:53 am ]
Post subject:
gafmo wrote: don't forget change a spring change the Needle also a reminder Check you fuel filter also Hi Gaf, the current springs are the cooper s type, and the needles are the AH2 cooper s 'rich'. 'should' be suitable. I guess a dyno run would help, the motor is so far from standard that trying to use 'standard' needles etc is only ever going to be a starting point! Thanks!

Author:	drmini in aust [ Sat Aug 11, 2007 7:03 am ]
Post subject:
Try closing the plug gaps a bit, I find .032" better than .035" with the electronic Pulsar dizzy. At .035" it does that too when cold. It takes more energy to spark a lean mixture..

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