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What carbs to use?

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bugedd

bugedd

Jedi Knight
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When I got my BE, it came with the Weber DGV conversion and the SU's in a box. The Weber is going to take some leaning out via jets to make it run right, and that made me wonder about putting the SU's back on. The motor is a stock 1275, and I may put a cam in it at some point, but that's probably about as far as I will go with the motor.
So what do you guys think, put the SU back on, or dial in the Weber? And should I determine which SU setup it has, and if so, how do I do that?
 
SUs. For sure.

My MGB came with a DGV and I got a set of SUs for it so that I wouldn't be ashamed to open the bonnet. :laugh:
 
It depends upon what you expect from the car, and how you plan to use it. If you're a boy racer, always in the upper rpm range and don't care about economy, go with the Weber. Get it dialed in and it's a done deal. You'll never have to reset it and it will serve you for years without attention. If you want low end grunt and plan to live in the lower RPM range, the SU's will serve you better while delivering better fuel economy. Once they are dialed in they tend to be be relatively maintenance free, but they do have more wear issues than the Weber.

Disclaimer:
At least that's what I've picked up from my readings, having no actual experience with Webers.
 
My 1098 MK1 came to me the same way, Weber 32/36 on the car, SUs in a box. I went back to SUs since the Weber wasn't dialed in and doing that well is a lost art IMHO that requires quite a bit of time money and fiddeling to get right and even then it's arguable if it's a better set up then the SUs anyway. I went through my SUs, put them on the car and sold off the Weber. My experience seems to confirm the conventional wisdom. Weber might have given a bit more at WOT but the low end stank, stumbled on tip in which was every time you touched the pedal, very annoying. SUs were fun to work on and car runs better and mileage went up, plus they look cooler and are "correct". No telling how well my Weber was set up though, so can't vouch for a comparison with a "spot on" Weber. I got to the point where I knew I needed rejetting and that's where it becomes $$ and time consuming.
 
Is there a way to tell if the su's I have are correct for the 1275 displacement?
 
They are, bolt em up and check em out.
 
Well I do drive the car hard, but not racing.
 
SUs hands down. Uber cool with a stock look.
I'm using twin HS4s on my 1380 and it is street-able
without throttle lag or stutter. It once had a single HIF6
and was much smoother on the street, had good gas mileage
and ran like a banshee at WOT.
The HS4s are maybe a bit much and aren't as "street" mannered as the HIF6....but......WOT with the 2xSUs is much more powerful.
HS2s are near perfect for a 1275 setup.

I don't race either...but I do flog a car now and then.
SUs work for me.
:devilgrin:
 
HS2's on a 1275. No question.
But they must be healthy.
Watch for leaking throttle shafts, etc.
If they are worn, you will be forever chasing your tail.

Many people curse SU's. Truth be told, I'm willing to bet
the people who have trouble with them never bothered the
freshen them before playing. Once set up right, you really
don't need to mess with them. Low speed driveability will
be great.

Paul
 
K, rookie here, how do I know if they are HS2's?
And where can I find info on rebuilding them so I can bolt them up and be certain I won't have issues?
 
measure the bore diameter - if is 1 1/4" they are HS2's, if 1 1/2" they are HS4's.

in terms of rebuilding, the most likely suspect is the throttle shafts, if you can wiggle them or do morse code with them, they are worn. If that is the case, you can rebush them yourself but, I'd suggest you get them properly rebuilt. I got mine done here in Canada but, the US go to guy is Joe Curto. If he doesn't know it about SU's, it isn't worth knowing. www.joecurto.com

getting my carbs rebuilt properly was some of the best money I spent on my car and transformed the way it runs.
 
HS2's are the only ones that will fit your stock manifold which I assume you have with the carbs and the stock manifold is the only one that fits your engine.(with 2 carbs). Could compare to whats offered on E-bay.

KA.
 
I went for a HIF44 on my otherwise standard 1275 It came with twin carbs but they were badly worn. my frogeye pulls from really low down & keeps going.
David Visard's book is "the bible" great tips on how to extract more power, many from slightly modified standard parts.
 
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