Carb needles and engine specs
Turbo Mini Forums

So then guys who is running what needle with what engine spec.

Useful information would be;

cc
CR
cam

then

needle
carb spring

what fuel pressure

also if you know it

advance curve or at least max advance on and off boost.


Just trying to make a matrx of who has done what with what degree of success. I have just done a search and there is a lot of information there but not all in one post, hopefully this will help people by being a central reference.....

No matter how close you think a needle is you must still get it set upon a rolling road or engine dyno. Even if by some chance the fueling is spot on you might be frightened by how far out the ignition is....

Edited by RogerM on 19th Nov, 2006.

Every day is a school day ...........

How fast and how expensive ...... the same question...

Everyone I know with a TM uses a modified BDD (which is the standard turbo needle).

None of the "factory SU" needles with codes are much use on tuned turbo motors.

i use an avonbar 8psi needle it overfuels at 12 psi so far though

Thank you for your replies.

I would be very supprised if you did just grab one off the shelf, have always used Mech Repairs rolling road as even though the guy makes more noise than a SC box when he's faced with an SU carb he does have a feel for them.

What might have been more useful as a question would have to asked......

what is the thickness of your needle at various points along it..........?

Not sure most people would have measured them though.

I also forgot to list fuel pressure on the original post ......

Every day is a school day ...........

How fast and how expensive ...... the same question...

This week we tested my new AEM wideband lambda on Benross' mini, as he has just started running hsi new engine and wanted to check the fuelling was somewhere in the right ballpark.

Well, this AEM gauge is a GREAT! piece of kit, and actually showed us that the standard BDD needle was fine fuelling wise when running up to approx 10psi on Benross' car!!!

However DO NOT take this as gospel on any other engines!

10 psi V std bdd
starting at shoulder

0 2.48 2.48 (0)
5 2.37 2.37 (0)
10 2.21 2.24 (.03)
15 1.92 2.03 (.11)
20 1.76 1.86 (.10)
25 1.62 1.75 (.13)
30 1.54 1.65 (.12)
35 1.45 1.58 (.13)
40 1.36 1.51 (.15)
45 1.31 1.46 (.15)
tip 1.28 1.43 (.15)

So the standard 10psi avonbar needle is approx .004" thinner in the middle and .006" at the pointy end

Metro turbo weekend driver,Mini turbo in the making again!

Heres the pics at 50X on the shadowgraph

Metro turbo weekend driver,Mini turbo in the making again!