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SU or Stromberg?


nick69

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Hi guys,

Ive just bought a rebuild kit for my CD150s and went to sell an old pair of HS6s. Now im thinking whether I should rebuild the SUs and put them on??

Whats peoples opinions on SUs on GT6s???
I see some people are having problems setting them up!!

Nick :)

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STROMBERGS!!!!!!!!!

They are fantastic carbs, the only thing the SU cack has over them is needle choice.
But Strombergs are great!

Only weakness is the diaphragms, replace them every 2-3 years. £5 quid and 5 mins!

SUs eat thier spindles quickly, tempermental too, they go out of tune quickly - thats why there are so many books on them, you need the help!

Rebuilding old Strombs is pee easy too!

SUs are only so popular as cars with more cache than a Triump, like Jags and Austin Healeys had them.

Strombergs are even suitable for Aero engines.

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Ah right so good, rebuilt and set up strombergs are more suited to our engines?

I dont really fancy getting into replacing the front dash pot tbh. If it was an easy swap out and they were as good then I might have done it.

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Isn't there a theory that was never really proved? SU's gave you slightly more power but worse economy. Strombergs the other way around. Hence why they never put Strombergs on Spitfires.
Although, didn't some US spec Spitfires have Strombergs? A very very small number.

Or is that just an old wives tale?




When I put twin SU's on my engine I did notice an improvement in torque. But then, I only put them on because the Stromberg was knackered so can't really comment.

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There's only more documentation on them because they were used on more cars - and more needles means more choice when it comes to tuning them. They're fine if you have a totally stock car - but not so if you want to mod it. Also more people tune SUs so know what they're doing.

SU's don't go out of tune any more than a Strombergs... and the spindles don't wear quickly - it's just most sets are knackered by now and need redoing.

There are arguments for both...!

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The bit about the books was tongue in cheek James.

But I firmly believe, that so many people want SUs or switch to SUs because of the old fallacies that a 'real' sports car has SUs.

They DO wear their spindles quickly, I've had it confirmed by a trader, you get blow by through the bushes after about 40k miles, Strombs regularly make 100k

My own experience is with 2 sets of HS2s. One less than 10k old the other nearly 35k old.
The newer pair go out of tune on a monthly basis, whilst the older pair sometimes last 3 weeks. The latter pair however need rebushing as they are gone!
Having experience those, I wouldn't touch any SU but the later Metric ones

In terms of needle selection, you are correct SUs can't be beat

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On both my 1500 and my Mk3 the SUs never went out of tune... if they go out of tune that quickly then there is something wrong with them...

The reason they are the choice for sports cars is because of the needle selection and the number of people able to tune them properly... if people are building modded motors you're not going to go for a carb that isn't flexible enough to do what you want.

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Quoted from jcarruthers

SU's don't go out of tune any more than a Strombergs... and the spindles don't wear quickly - it's just most sets are knackered by now and need redoing.

There are arguments for both...!


I'll hang my overalls up then! SU's have kept me busy in the workshop for the past 30 years, very nice source of income thank you very much. Not scientific by any means but on average SU's (at least on Triumph's) need a set of spindles/butterflys every 30-40,000 miles. Needles and jets can be worn out in less than that. For Strombergs double those values at least. Our Chicane is about ready for another carb rebuild it's Strombergs were treated to a full rebuild at 100,000 miles. Now at approaching 300,000 miles it's time again. If it had been fitted with SU's they would have been on there sixth rebuild now.

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And another thing! Strombergs tolerate wear much better than SU's. A worn set of Strombergs can still be tuned to give decent idle/economy etc. Try tuning a worn set of SU's and they would go out of sync, have an erratic idle, and be using the juice again within a few days.
Don't get me wrong I'm not anti SU (one of the better things to come out of Austin Morris) I'm just saying in practical day to day terms Strombergs live approximately twice as long as an equivalent SU.

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Jesus, I think Dave P agreed with me!  :o :o

Absolutely Ferny, get the SU/Stomberg manuals pack from Burlen, its about £13 and covers each and every part, and also has technical sections. Well worth it IMO

PS> I'm not trying to say rip the SUs off your car, far from it they are fine carbs, just trying to relate my experience and stick up for poor old Strombergs!
SUs got Austin Healeys, Jags, Spitfires, Sprints, etc - whereas Stromberg got stuck on Volvos!

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No, what I meant was that when I put my new air filter on with my SU's I had instant access to ideas on what springs and needles to use.
When I got the car it had a single Stromberg and a K&N. The general knowledge was that I needed to change the needle but I couldn't find out any info as to what to change it to. Looking in articles in the Courier simply said "best to use a rolling road" and there was nothing I could find on-line.


The Stromberg which if it had been on the car since new and the speedo was correct  had only done 83k miles and wouldn't stay in tune. ;)
Although I know the engine was replaced in the 80's so have no idea on when the carb was last fiddled with or rebuilt etc. So assume it had done a lot less miles.

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I concede to superior experience - I just never had a problem with my SUs running them over 15k or so...

It still seems to be SUs are easier to tune with regards random needles and modifications.

I was in talks with Burlen a couple of weeks back as they wanted me to make them a bespoke SU-needle-comparer-thingy - don't know if anything will happen from it - but perhaps I can suggest it to include Stromberg needles too...

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I agree with the general opinion; Nowt wrong with Stroms, a much maligned carb (by some). Mine were overhauled 50,000 + miles ago and are still doing a grand job.

But if you want to mess about with different needles etc. then SU are the way to go as you are very limited in choice/availability with Strombergs and will always end up compromising. (I'm not trying to contradict vastly more knowledgeable people on here, I'm just talking form my experience).

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