there are some common miss conceptions when it comes to the su. I will try to settle them. weber guys please dont flame me, they have their uses 3-9000 rpm,I am only trying to inform not slam.

Ok here goes,

1: they don't produce power.
have you driven a stock 1200 lately the stock down draft chokes the engine down to the 60 or so H.P. they make.

2:they are hard to tune
again not so. there is a system to tuning an su. once learned you can tune a new set in minutes flat.

3: they are not reliable.
HELLO nissan, jaguar, triumph, rover, and tvr would not put these on anything if they were not reliable.

4: fuel milage will tank.
again not true if tuned properly and driven reasonably they will equall or beter the stock setup.
e.g. I have a datsun 1600 wagon with a 2100cc L-20 and 38mm su's I get between 29-32mpg that is a US gallon.

I hope that this has helped out some
I am aware that the weber is the ticket for top power, but how often do you drive around town at 5000 rpm honestly!

Phil
su owner since 1990

Quote:Then how do you explain british car's electrical problems? Could be a myth also ... british cars are the one kind I've never owned.

#1 is demonstrated by the fact the A12GX race cars used the SU-type Hitachi carbs.

For me, they are hard to learn to tune.
I can't figure out what position the piston and needle are in under various driving conditions. I think i understand what the positions on the needle are and how the piston spring and plunger/oil affect its movement but what is the piston ACTUALLY doing while I drive around.
One of these days I'll rip the hood and air cleaner off and mount a video camara to the fender.
I cant afford to put this on a dyno. Do you have any suggestions?

Im not sure that Im entirely convinced, especially after point 3 being introduced as evidence. Ok Nissan is cool but the rest of those British heaps of junk leads me further away from an SU setup. Please dont get me wrong, if a set of SU's were given to me for an A series setup I would endeavour to use them to their fullest. Nutcase, since you are now our resident SU expert, please post some technical info on tuning etc etc as there are plenty of SU's out there...and plenty of keen Datsun owners. We just need educating. Do me a favour though and dont use bad language on the site again....words like Jaguar and Triumph arent acceptable!!!

I'm no expert on SU's nor webbers neither. My coupe when I bought it had twin Su's on an A14, and they were nothing but trouble they started out pretty good, nice bit of power, but then they started palying up and tuning them didn't work, then it was one thing after the other, until I finally bought an A15 with twin webbers(40's). Much better performace due mainly to bigger carbs and displacment and also engine had alot of work done to it.
But with webbers they have never played up on me, I am slowing getting the hang of tuning them, with SU's tuning them was a pain especially getting the mixture right as it would be sounding good but then they would go all wrong after driving for a little bit,
I think Su's would be good if I had a good set and I was actually shown proper tuning. (nothing beats being shown something rather then reading it)
Well thats my 2 cents

Cheers
Damo

im goin to stick to my dellorto's they may use #### loads of fuel and only work in certian rpm rane but there performance is 2nd to none i mean why did the datsun 1200SSS come out with 40 ml dellorto's they gave them a very mild cam aswell and found 89hp