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I hvae K&N filters on my car and I remember being told that BAL needles are better for this kind of setup. Does anyone know if this is right?

Phil, the "right" needle for any set up, is the one that gives you
the correct fuel mixture.

I have Ramflow air filters, which despite their name, are very good,
if you want minimum restriction to your air flow.

When I fitted them, with standard needles, the thing would not rev
past 3,500 RPM, due to the mixture being too lean.
After going richer in three stages I ended up with BAL needles.
Quite a few others have found the same needles suitable for their
set up.

However, unless your engine is running lean, there is no advantage
in fitting richer needles, & in fact, there would be some
disadvantage.

If you, or a trusted mechanic friend can "read" the spark plugs, you
should be able to see if you require a richer mixture.

If it is a bit lean, it will take quite a few miles to run without
any choke, from a cold start.

Because of the way the choke works in an SU carby, applying about
half choke is similar to going three needles richer. Does your car
go better with some choke applied?

Quite a few 7s, with K&N filters, have found BAL needles suitable
for their cars, so check yours, & if you're realy keen, tune it on a
dynamometer, [rolling road in UK speak].

Hasbeen

Hi Hasbeen,
My car when cold does runn a little better with the choke out, but I have found these days that she does not like the choke out as much as she did now. When I pull the choke out now she will start to splutter and does prefer the gass peddle now.

Phil, reading this, & your other post, on the Sprint engine, I think
your carbys may be flooding, or at least running with the fuel level
too high. It can happen when a new fuel pump gives more than 2 PSI
fuel pressure. This would give a rich mixture, but in a bad way,
causing your plugs to be sooty, as you mention.

I think you should check this, & correct if necessary. There is no
point trying to power tune, until the basics are right. Once you
correct thatever is causing the plugs to get sooty, you may then
require those BAL needles.

Hasbeen

<b><font color="green">Hasbeen, I do honestly think that this could be the issue with the new pump fitted as she was running sweet before that. Shows had bad the old one was lol.
Is it best to get it on to a rolloing road to sort this out of will me turning down the idle revs via the carbs help?</font id="green"></b>

Phil, you would only be wasting money on rolling roads, until you
have checked, & adjusted as necessary, your fuel pressure, & fuel
level in the float chamber of your carbs.

You require someone who knows SUs to do this, & there is no point
paying rolling road time, while its done.

If I were you, I'd talk to one, [or two] of the top UK TR7
specialists, that I keep reading about in here. From what I read,
they would have you sorted in a very short time.

I have found, many times, that a stock, or very near stock, engine,
running at its best, will give much better performance than a much
worked engine, which has not been properly tuned.

In the 60s, I found that because of rapid wear, re-bushing the
distributor of a 30,000 mile Morris Cooper would give a much greater
improvement in performance, than half the price of the car, spent on
hot bits. Infact I made quite a bit of money because of that knowledge.

Hasbeen