DCOE, DGAS, DFAV yadda yadda yadda.

[tigran]

I know everyone is completely obsessed with webers - I love them to bits, the noise, the spluttering - everything about them. However half decent ones cost a bloody arm and a leg, so whilst stripping the V8 with it's oversized (compared to a pinto) everything I was looking at the nnnnngggmahoosive twin SU's that feed it which got me-a-ponderin...

Why are there not more applications of large SU's instead of webers on tuned engines? They are apparently smoother providing a better flow of petrol to the engine so why not use them? Don't think I have ever seen a 4-pot ford engine being powered by large SU's. Seeing how I have the spare ones laying about from the spare V8 I think I will have a go at fitting them to the pinto in the capri once the hot cam is in.

Discuss!

[tigran]

p.s. surely it can't just be because they look goofy.

[bodieanddoyle]

twin su pinto manifolds are mega rare! they are supposed to produce mountains of torque.
webers flow more air than su's, but I reckon su's are better. limitless tuning with just a pillar drill and a piece of wet'n'dry. diy tuners dream (at least one who can't afford efi).

[penski]

Yup - they look like nipples.

*n

[burns]

There are a few reasons, but the only one I can remember form a book I was reading on tuning SUs is that they have worse throttle response due to having to wait for the needle to got sucked around by the vacuum. I'm pretty sure there were others, but I can't remember what:D.

[rustingdeathtrap]

Su's are a better option for economy and smooth running but you can make more power with webbers.
Oh yeah, and webbers look sexier ;D

And thats about all i know about carbs.
I'm sure someone cleverer will come along soon though.

Edit; See, they came while i was typing that ;D

[arthurbrown]

All in the fannymoulds, surely.

BL stuff had 'off the peg' SU tweakage available back in the day... Fords had Weber preferential treatment....

The same is true today.
T'other day me & Russell were researching Dolomite stuff.... brand new twin big SU's + fannymould for his beast... ~£350. Similarly proportioned Weber set up... £900

[Seth]

Well I'm a lot more familiar with SU's than the Webers but I think that for the same size carb throat a Weber will flow more air at what as it is a more straight-through design whereas the SU's have the hump to change the air pressure and get the needles working properly. That'd be why even BL type race cars ended up with Webers for race purposes (eg Spitfire Le-Mans cars).

As Jonny69 mentioned in the other Weber related thread last week if they're properly set up then they function as well as anything thoughout the rev range. My personal view is that they are more likely to need professional (rolling road) attention to reach that state. SU's are perhaps simpler for home tuning though they're still easy to muck up if you don't understand what you're doing.

What I would really like to get my hands on are some of the experimental twin choke SU's made for the Triumph TR racers! ££££££££!

[tigran]

Oh well guess i'll just have a go and see.

[jizzy gillespie]

how about 4x mini 850 su,s on a pinto, just for fun!!!! backwards retro tuning, curse word all these throttle bodies ;D ;D

[Deleted]

It's funny because over in the States they use 4-barrel Holleys on Pintos.

One thing with using 4 SUs on a 4-banger is it's four carbs that need synchronising and are likely to go out of balance, whereas with a DCOE it's only two. I reckon a quad of SUs would look and sound awesome though. Wouldn't be too hard to make up some adapter plates for a twin DCOE manifold.

What about 4 downdraught Solex or Zenith carbs? Cheap as chips

[Paul H]

Quad SUs? Nah - you want quad Amals!!!! ;D

[oldschoolgeezer]

Or how about quad mikuni's!! ;D

[slater]

Its all fashion driven relly. SUs are a great choice for a road car, webers are not but cous racing cars have webbers they must be better right! .

Bike carbs are just a modernised version.

[tigran]

I'll see how difficult it is to get a couple of the su's from the spare V8 mounted up. Can't be that tough...

[SeventyNine]

ive got a load of standard single port 1.3 crossflow carbs - 4 of them maybe?;D

[akku]

Mounting them shouldn't be too much of an issue. Making sure the inlet manifold is of an appropriate design might be a little harder.

A couple of tuners in the 60s liked SUs. Aquaplane, Alexander Engineering, Brabham, Blydenstien... all did conversions for Fords, Vauxhalls etc using SU carbs. Come the 70s the Webers seemed to get the drop.