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Guennie

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Nr Newmarket, Suffolk

9th Jun, 2009 at 11:17:20am

Hi,

I've been driving about a bit in my mini now i've put my new engine in but have a small issue with it when cruising (not chav style cruising!!!).

Under acceleration and deceleration the engine is really very smooth and runs lovely, however it doesn't seem to cruise very well. It seems to be hunting a bit and is quite jerky. There are a few throttle positions where i can make it cruise nicely at 30mph but there is clearly something amiss that i can't quite put my finger on.

I'm running megajolt, but haven't had it rolling roaded yet. I thought it best to run it in first and try and get it running as smoothly as i could.

Any help on diagnosing and solving this problem would be great.

Cheers,

Guennie

100% BMW Free

Mini_Andy

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Swindon

9th Jun, 2009 at 11:20:07am

i would say put it on the rollers

Paul S

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Formerly Axel

Podland

9th Jun, 2009 at 12:09:39pm

There is a known problem with the transition from cruise to light acceleration with the SU in a turbo application.

Turbo Tel covers it is this post:

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."

chinlesswonder

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In the garage......again!!

9th Jun, 2009 at 02:28:05pm

I agree with Paul above, mine is exactly the same, chuggs a bit, but accelerates lovely, it feels like its got a big cam in making it cough, i put it down to air speed across the head with the large valve head i have.

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

Mr Joshua

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Luton Bedfordshire

9th Jun, 2009 at 03:23:46pm

I believe the last time this subject came up it was when the question was asked about the part throttle lean of pipe and the apparent massive flat spot it can cause when trying to accelerate gently.

Do you have this pipe still fitted. Its the pipe that runs from the front of the carb just infront of the dash pot to the left hand side of the carb just below the dash pot.

Own the day


Guennie

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Nr Newmarket, Suffolk

9th Jun, 2009 at 03:30:24pm

Thanks for the replies :)
From what you've said it sounds like a fueling issue then. I'd like to have it rolling roaded as soon as i can, but as i said i'm still running it in at the moment!



On 9th Jun, 2009 Mr Joshua said:

Do you have this pipe still fitted. Its the pipe that runs from the front of the carb just infront of the dash pot to the left hand side of the carb just below the dash pot.


Yes i have this pipe connected. Should i block both ends of it off? What do you suggest,

Cheers,

Guennie

100% BMW Free

Mr Joshua

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Luton Bedfordshire

9th Jun, 2009 at 05:18:21pm




On 9th Jun, 2009 Paul S said:
There is a known problem with the transition from cruise to light acceleration with the SU in a turbo application.

Turbo Tel covers it is this post:


This thread as well as the one Paul has given a link to may be of help infact the one paul links to is mentioned in here as well
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=286255

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chinlesswonder

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In the garage......again!!

10th Jun, 2009 at 10:21:13am




On 9th Jun, 2009 Guennie said:
Thanks for the replies :)
From what you've said it sounds like a fueling issue then. I'd like to have it rolling roaded as soon as i can, but as i said i'm still running it in at the moment!



On 9th Jun, 2009 Mr Joshua said:

Do you have this pipe still fitted. Its the pipe that runs from the front of the carb just infront of the dash pot to the left hand side of the carb just below the dash pot.


Yes i have this pipe connected. Should i block both ends of it off? What do you suggest,

Cheers,

Guennie


I think it works ok on some engines, not so on others. I had to cut mine and block each end off. Might be worth a try see if it improves the drive, you can always connect it back easily.

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

Guennie

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71 Posts
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Nr Newmarket, Suffolk

10th Jun, 2009 at 02:31:19pm

I'll give this ago tonight and see what what happens.

Thanks again

Guennie

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