carbies

[crystalmeths]

Hi all just wanting to know which is the better set up in carbies , weber , holley , twin mikunies , for performance more than economy thanks for any help regards Chris

[75glnt]

As far as I know. A weber is a good performance carb. Those dcoe carbs.

[turbosigma]

That efi mani ya have would be another option.

Go grab a efi Magna loom/computer from pick-a-part. Done....

[geezer101]

Define 'better'? Weber DCOE side draughts are a good carby for top end power, but not great for street use and are not light on fuel (and in pairs can be pigs to tune, and aren't cheap...). The Weber 34 ADM down draught will flow better than a stock Mikuni carby and won't sacrifice drivability or economy too much but has to be tuned to run on your engine (ideal for a 2.6 astron). A 2 barrel Holley - nobody talks about these so no idea. The stock Mikuni carby isn't a bad bit of kit but needs to be lightly tweaked to get gains in midrange and smooth out idle (this depends on what type of Mikuni - older ones are easier to mod). Then you can also go down the path of quad carbies (look up Superscan's work on the site to get an idea of what's involved). They can deliver great performance and fuel economy gains but are not a simple bolt on option. It comes down to how much you're willing to invest versus what you are trying to achieve. If you're handy with a spanner and can pull down a carby (without having anything left over) you've got options.

[davetrees]

What sort of engine are you running ? If it's basically stock, then twin sidedraughts are a waste of time ... you need the headwork & cam to take advantage of them, or all you will do is use more fuel. They are not a "bolt-on performance upgrade".

For a street engine, probably a single downdraught Weber or similar would be the go, as geezer suggests, unless you go the EFI route.

[crystalmeths]

That efi mani ya have would be another option.

Go grab a efi Magna loom/computer from pick-a-part. Done....

Steve they went missing five seconds after i got it home mate

[natosig]

Im running a single 45 mm side draught delorto it not bad for street use still stock engine so much better than stok carb to make the most out of the carb a cam upgrade would be good

[crystalmeths]

What sort of engine are you running ? If it's basically stock, then twin sidedraughts are a waste of time ... you need the headwork & cam to take advantage of them, or all you will do is use more fuel. They are not a "bolt-on performance upgrade".

For a street engine, probably a single downdraught Weber or similar would be the go, as geezer suggests, unless you go the EFI route.

i am running a 2.0 litre with oversized pistons , crow cam stage two , and balance shafts removed

[75wagon]

Regarding carbs, I'm pretty sure the 180 Holley is just a Weber.
Yes, a correctly jetted and tuned down draught weber will increase performance over a stock mukini (not a lot, but it will happen).
Modifying to Fuel injection would (or should) increase gains, but the quad motorbike carbs correctly jetted sound horny as hell, and perform better and more effieciently then twin sidedraught webers in all parts of the rev range. Superscan811 has also proved they run cleaner then EFI as well, so they should pass emissions testing with no problems. And yes I have put my money where my mouth is, I just need to get a car sorted to put them in, and finish making that damn intake manifold (so many things I have on the go, and not enough time to do them).

[davetrees]

I'm pretty sure the 180 Holley is just a Weber

Yep, it's basically the same carb as a Weber 32/36 DFV. A much better, more easily tunable carb than the stock Mikuni but performance gain on a 2L would probably be marginal at best (seeing the 32/36 originally came off a 2L Ford motor anyway).

Something worth considering in simple(ish) downdraught carb conversions could be a Weber 38 DGS (bigger bores, synchronous opening of both barrels) ... fits same baseplate as the 32/36 or Holley. You would still have to spend some tuning time getting the jetting etc right though.

[Scorpma82]

the last model Magna to run carbs is essentially a bigger version of the sigma mikuni...they run bigger venturies and jets from factory...so they bolt on the same way as factory

(best way to picture these two carbs is comparing a 450Holley and 600Holley)

[geezer101]

the last model Magna to run carbs is essentially a bigger version of the sigma mikuni...they run bigger venturies and jets from factory...so they bolt on the same way as factory

Do these have the integrated EGR 'bullet' that goes into the manifold? It's actuated off a linkage on the carby and opens the the exhaust gas gallery into the plenum in the manifold base. If that's the case the only way you can use this carby is with the whole manifold - then you're left dealing with the thermostat housing being at the wrong end of the head.

[Scorpma82]

to be honest, i can't remember,

All i remember when being shown the two carbies was that they looked identical...was some tme ago when i saw the comparison

[BAD-SIG]

the last model Magna to run carbs is essentially a bigger version of the sigma mikuni...they run bigger venturies and jets from factory...so they bolt on the same way as factory

Do these have the integrated EGR 'bullet' that goes into the manifold? It's actuated off a linkage on the carby and opens the the exhaust gas gallery into the plenum in the manifold base. If that's the case the only way you can use this carby is with the whole manifold - then you're left dealing with the thermostat housing being at the wrong end of the head.

These also came out on the GN Sigmas, so just use the Sigma manifold