17 replies to this topic

[DMLC71]

Remember to re locate your battery to the boot for webbers
Cheers

[warrenm]

Agree with Bomber, SU's are the go.

[Dodgey]

If you are still keen to investigate Webers, give Daniel a call at Weber Performance, Braeside Vic ph 03 9587 3277. (Triple Webers with linkage, trumpets, filters and set-up wont be cheap).

[I'm a Red Motor fiend]

You can go just as fast with SU's on the street. Bomber and Warren are correct. What are your engine specs? Head, cam, compression etc etc. if it's not built, it would be a colossal waste of money putting webers on.

[Dr Terry]

Slightly off topic, but what ever happened to Dellortos ? Weren't they the alternate 'quality' equivalent of Webers ?

 

Reading these various links, it seems that FAJS are Chinese cr@p.

 

 

Dr Terry

[jd lj]

As far as the fajs carbs go I have no experience with them myself but have been told the quote "even the fajs carbs can go alright if you replace all the brassware (jetting)". Doing that alone will cost you a few hundred dollars and you won't have much of a resale value in the future when compared to real webers or dellorto's.

Dellorto's are a good quality alternative to webers but the jets aren't quite as readily available. However atleast the dellorto engineers understood the physics of how to make emulsion tubes that work, I'll elaborate on this later.

[jd lj]

If your not scientifically minded then Su's or Strombergs may be a good alternative as the tuning isn't as involved as it is with webers. All these options will give very good performance, some people tend to have a stronger bias towards either Su's /Strombergs or webers/dellorto's. I think that it comes down to what you have experience with and who you want to listen to. There's always going to be people saying one is better than the other but they can all be made to work well.

[jd lj]

If you buy new dcoe's from "Weber Performance" you can discuss with Daniel what would be suitable jetting specifications as your starting point and exchange the jets that are fitted to the carbs when they are made with the preferred choice at a discounted rate.

If you buy used dcoe's expect to have to replace most of the jets to something suitable for your application. Quite often used jets have been drilled out and modified so you must check the aperture size and don't trust what is stamped on the side. If it proves to be different grind off the stamped number to avoid future confusion.

You also must ensure that the idle mixture screws haven't been over tightened as this can crack through into the barrel and make adjusting the idle mixture screws difficult, ask the seller for a photo of the barrel roof below the idle mixture screws.

Different models of dcoe's have different progression hole patterns and are not to be used as a set if they don't match, otherwise you'll have trouble tuning them. Again ask the seller for a photo of the progression holes on each carb to make sure that they match and beware that sometimes they've been modified. The lids of the carbs will be stamped with their size and model number but beware that the lids are mostly interchangeable between models and sizes. Most of the used dcoe's for sale tend to be 45dcoe152's or 45dcoe13's and various 40dcoe models. Some models of different numbers are made to be used as sets when they were fitted to their original cars. I think 40dcoe16's and 40dcoe18's are an example of this from memory along with the RT CHARGER 45dcoe75,76,77. These model numbers are just from memory some may need confirmation which I can check my notes if necessary.

If you don't intend to use your car for competitive purposes then 40dcoe's tend to be slightly cheaper than 45's when sold second hand. On a street car 34mm chokes will give you good torque in the lower rev range that you'll be using most of the time and they'll still let you rev beyond 6000rpm's, many people use chokes that are too big and then complain about poor low rev throttle response, but fit appropriate chokes and you'll grin from ear to ear. 40dcoe's actually have been shown to have better flow rates than 45dcoe's with up to 34mm chokes, anything bigger and then 45dcoe's flow better.

[jd lj]

If you choose to use dcoe's then most so called professional tuners (but not all of them) will balls it up because they don't really understand the physics involved, but they'll still take your money. Then you'll be on the forum or calling someone like myself and with the help of some diagnosistic equipment we'll tell you how to fix it.

Most people will tell you to use f2 emulsion tubes for a Holden 6 cylinder, they'll work to a degree but you'll most likely spend a lot of time trying to get rid of a hesitation at around 2500rpm's. If necessary I can explain why these are a unsuitable choice of emulsion tube in a dcoe on any engine, most standard emulsion tubes are.

There's much better performing tubes available made by a guy in the US called Keith Franck. I recently fitted my set to a friends car to show him the difference and he couldn't believe how much better it went. I have also just received the latest version of tubes which so far by all accounts are out performing anything used before and there's also a version for other weber types and dellorto's. I'll test these tomorrow.

I've probably made all this sound overwhelming but if you approach webers methodically they are easy enough to tune.

[jd lj]

https://www.webstore..._id,other_items

Here's where to get some real dcoe parts.

[LC-GTR-1969]

I love webers and love SUs... I have both and have run both... the webers are good but as JD said, be prepared to learn how to tune and refine them as most tuners will only get you in the ball park- they will get max power sorted on a chassis dyno but low down drivability will not likely get a look in... 

 

SUs are cheaper but to be honest they still add up, but the tuning price should be cheaper than the webers. 

 

Be prepared for about $1200 for 1 3/4 SUs with good linkages and rebuild on a decent manifold. Then about $800 for dickin around and tuning on a dyno. Or a few hundred if your prepared to self tune. 

 

As for a street car, I tend to agree, the SUs give better street performance from my comparisons, although the webers are also quite good if you run conservative chokes. There is not a heap of difference, just that the webers have a fixed choke setup which means you need to comprimise with either the bottom end or top end... you pick a power band and choose the chokes accordingly- ie 3000-7000rpm. The SUs are more forgiving due to their variable venturi design. 

 

From my back to back comparisons (bum dyno only as yet) the webers excel at higher rpm. My SUs pull off the line much better than the webers. I can see why the webers are the pick for circuit cars as they spend all their time between 4000-7000rpm and this is where the webers will excel. 

 

The SUs should give a better 60 foot time in a street type drag car (launching at say 3000rpm), hence why I imagine the drag racers seem to run the SUs. 

 

Furthermore, the drag guys would also lean towards the SUs as its a right pain in the jatz crackers running webers on methanol as you need huge main jets and it causes tuning gremlins...  SUs can be adapted for meth a fair bit easier. 

 

If you are keen on webers, dont bother with the FAJS- no resale value and only marginally cheaper... I would run a FAJS carb if they were half price but theyre not, so stick with the genuine as you will regret buying the FAJS imho. 

 

You could buy some 1 3/4 SUs in good nick and throw them on, at the end of the day if you dont like them you can sell them and the whole exercise will not cost you much. 

[jd lj]

I need to amend my earlier post about the dcoe models of different numbers that make up matching sets.
Rt charger =45dcoe 53,54,55,56
I think 40dcoe18,19 are a set as are 40dcoe 27,28 and 40dcoe31,32 and 40dcoe76,77.

From my notes 40dcoe44,45 are both pollution models that you want to avoid if used for performance applications, I can't remember the difference though.

42dcoe8's are another option and use the same chokes, auxiliary venturis and ram tubes as 40dcoe's. However the 42dcoe8's have only two progression holes in an unusual pattern and may need some modifications.

As for webers not suiting the lower rev range that just depends on your choke size. With the appropriate chokes a webered engine will pull very strong from idle to redline, but it's true that you have to select chokes to suit your preferred rev range. I'm not saying that they are better or worse than Su's but just that they are capable of whatever you want if tuned correctly.