SU Carb Needles/Jets

[Redneck Rocket]

Hello all. I considered posting this in racing technology but it didn't seem terribly technological and I thought I might find more expertise here! I've finished the engine build on my Spitfire and driven it about 100 miles on the road. I upsized to 1.5" SU's from 1.25" that were on the car. It has a 280 degree cam, full 4-2-1 manifold & exhaust, fan replaced with electric, head skimmed to give 10:1 compression and 3 angle valve seats. I'm concerned that it is running too rich and needs different jets and needles. Not being a rich man I can't afford to take it straight to a rolling road and pay them for an hour of their time, although I will have to pay someone to set the ignition timing correctly. Does anyone have any practical tips for setting up the carbs and getting the right needles/jets?

[terence]

It would help to know what needle/jet sizes you have now. To spend ,say 60 quid now could possibly save a rebuild in a few races time.

[Redneck Rocket]

Is there anywhere in the London/SE area that I could go? I think its worth spending a little bit but I don't want to drop the car off and come back later to find that I'm getting billed for 4 hours time. I just want to get the right needles & jets put in and have it set up properly.

[275 GTB-4]

Originally Posted by Redneck Rocket

Is there anywhere in the London/SE area that I could go? I think its worth spending a little bit but I don't want to drop the car off and come back later to find that I'm getting billed for 4 hours time. I just want to get the right needles & jets put in and have it set up properly.

You could run the program first and make sure you have needles that are in the ball park...then the dyno fella (the rolling road fella) can get it spot on with his expertise and few file cuts

Don't forget to check the springs as well.

A useful site for selecting and comparing needles is http://www.mintylamb.co.uk/suneedle/

The needle matching program is called "WinSu" - do a google search.

[Brendan Roberts]

Southern Carburettors in Wimbledon are very good and have a rolling road. Unit 6, Nelson Trading Estate, Morden Road, Wimbledon SW19 3BL - 020 8540 2723. Not sure of costs but I have always found them very sensible and competitive.

[TorqueWench]

Hey Brendan - have you finished my father's old Elite yet???

I'll be racing the 18FJ at Combe this weekend, and John will be racing it at the Gold Cup! Will you be there?

[MGDavid]

Another well-satisfied customer of Southern Carbs
Give them a call to check the hourly rate, Dave is the r/r operator so ask for him, mention me if you like, he sets up my Midget. If you ask nicely and sign the visitor's waiver book, they will let you stay in the workshop and watch. Don't forget to take a notebook and write down all the settings, needles, etc, so you know the spec when it's finished.

[TorqueWench]

Originally Posted by Redneck Rocket

Is there anywhere in the London/SE area that I could go? I think its worth spending a little bit but I don't want to drop the car off and come back later to find that I'm getting billed for 4 hours time. I just want to get the right needles & jets put in and have it set up properly.

Are you going to be racing it Redneck??? (I feel a plug coming on...)

[Brendan Roberts]

TorqueWench, Elite is in the paint shop, most of the major components are on my garage shelves, rebuilt and waiting to be fitted and the engine was collected by the engine builder at S'stone, so hopefully making real progress at last. Been sharing Steve Hill's car this year.

Will be at Castle Combe spectating whilst my wife and children visit Granny! See you there!

[MGDavid]

where's the Mod when you need one ?

[John Turner]

I'm here, I'm here ...... and trying to show tolerance!

On the other hand ....

[esper]

Originally Posted by terence bower

It would help to know what needle/jet sizes you have now. To spend ,say 60 quid now could possibly save a rebuild in a few races time.

if you live remote , i would say , buy a haynes manual and get your hands on a decent lambda/ co box!!!!

[Tim Falce]

You could get the Burlen Fuels book on SUs or the Veloce book on tuning SUs, both very helpfull and not too expensive. Dont forget the jets will be the same, you only change the needles and springs.

[TorqueWench]

Originally Posted by Brendan Roberts

TorqueWench, Elite is in the paint shop, most of the major components are on my garage shelves, rebuilt and waiting to be fitted and the engine was collected by the engine builder at S'stone, so hopefully making real progress at last. Been sharing Steve Hill's car this year.

Will be at Castle Combe spectating whilst my wife and children visit Granny! See you there!

Good choice!

[Redneck Rocket]

Thanks for the advice guys.

I've contacted Southern Carbs and they said £150-225 for a rolling road session + £20ish for needles if they are needed. Does that sound reasonable?

Sarah, I'm definitely hoping to race it. Considering a few places but the CSCC is definitely one of them - I might have a few friends along to have a go with me. In fact, I think you know my friend Jamie Harfoot?