tr7triumph.com

My car is pretty standard (as far as I know) but has a tubular exhaust manifold. The air filter is still stock panel type. I do find that, although it is supposed to be a high revving engine, it does not seem to like to go much above 4.5-5k. In normal driving I only use 3-3.5k anyway but occasionally overtaking etc it seems to run out of breath. The current needles are standard BDM and I was looking to change to BAL to try and get some more upper end performance. The carbs are SU HS6 waxstat type (and never given me a problem).

Finally getting to the point, the Burlen site lists two:

BAL: .100 Jet Needle (spring) CODE BAL
and
Needle BAL CODE CUD1110 (currently out of stock)

Both are the same price but what is the difference? I can get the CUD1110 from others (ie Robsport) and it seems to be listed for all years so is it OK?

I had my needles changed during a session on the rolling road which improved the power output by about 20%. The car revved better and didn't run out of puff at higher RPM so would suggest this is the way to go.

Cheers

Howard

You are probably stranded in no mans land. If your tubular exhaust is a good one you are half way towards needing the BAL needles. Fitting them will not give you any improvement if you don't remove the inlet strangulation of that awful filter.

Throw out that air filter, & fit something that can breath, & the car will tell you to fit the BAL needles. Combined with decent breathing they should give you about 15 to 20% increase in power over the stock set up.

This does not necessarily respond all that much better to high revs, but will improve performance considerably. I don't use higher revs much more than before, as the better breathing has improved lower end performance so much it is not needed in roads driving. From about 80 Km/H, [50 MPH], I find overtaking in top is just as quick as using lower gears.

I came to BAL by trial & error. After fitting a good exhaust & easy breathing filters, the thing would not rev past 3750 or there about. It simply flat lined. Figuring the problem was lean mixture, I went up in 3 stages through slightly richer needles each time, until I got to the BAL, which worked beautifully.

Some time later I proved them on a wheel dyno.

Hasbeen

Thanks all, I am aiming to fit BAL needles and will then look at the breathing side. It is probably more mid range torque I am looking for as I am used to turbo engines in my other cars. I don't tend to rev the head off (after all, it is old like me).

However, can anyone explain the difference between the two needles offered by Burlen? Just want to make sure that if I get the CUD1110 ones from Robsport (who are normally good anyway) I am not going to be getting the wrong ones for my carbs.

Might be of interest. Thread from 2009 on SU needles.

viewtopic.php?f=2&t=11089&p=78820&hilit=Triumph+adversity#p78820

Looked in my SU needle book for the needle details, you can see the different profiles at each stage.

Standard BDM needle here:-


Optional BAL needle here:-

Thanks, had seen that elsewhere and it clearly shows the difference.
I had a chat with Robsport and they could not tell me what the difference was but only ever fit the CUD1110 so I ordered two. Ordered Monday afternoon and delivered yesterday (Tuesday) which was pretty good. I am sure it will take me much longer to get around to fitting them as I have to get things done on the other two cars but will report back when I have them in.

A friend put on headers/sport exhaust (from S&S I believe), changed out the Stroms for SU's and had a K&N air filter. No problem reving after that. He eventually went the Sprint engine route but ultimately (after a missing oil bung and electronic ignition failures) had a thrust washer problem that he ignored until engine was wrecked. Now putting in a tuned Rover V8 which is where he should have went in the first place.