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Why would you not use an EFI Hardware DCOE throttle body's being they are manufactured here in Australia? I will say though Webber DCOE style carburetors are the closest thing to injection due to the way the fuel travels into the chokes & into the cylinder head. EFI hardware throttle bodies are a lot more direct & simpler design. By the looks of things the efi throttle bodies your using look very complicated.

Man miss my LJ it was a import from Oz to here in New Zealand put a JP 202 in it had a 350 2 br Holley then a 465 4br holley bit soft down low and a 2 br weber off a V6 Capri for long trips or daily ,holley for Fridays and weekend ,semi hi stall converter frankinstein Trimatic guy built me at work from HQ,HX,VB bits he had lying around had to buy new seals and few other little bits and a cut down EL Xr6 LSD 3.3 maybe fast sorted car ,commo front brakes big sway bars ,gtr wheels on 225 low and fast with a cheesy XU1 rear spolier,early 90s they wernt worth alot lol got rid of it for a Yamaha FZR1000 that i got into heaps of trouble getting chased by cops losing licence uuug should of keep the Torana it was a happy car

I have run with Dellorto Carborators 48mm Chevy 356cui 0.40 borr 4 bult block.Corvette 1974 No no transbrake run 10sek taimes 1992 1600kg car.Th400 (Aut) 201M 6.9sek Real Street car..I Build Twin Turbos 95-96 Efi Vems In may Corvette.Hope com tou The Streets 2025...Real Street car offcors..Turbos are smal K27 Have k29 if I want more flow...I tink thes K27 are god.Have Bigger Rear end 12 bult 31 splains.Toms parts..

I have A Deceleration fuel Cut out system in my 750 demon carburator !!! These Webber style carburetors Have so many adjustments that you can get the correat fuel ratio at all Engine demands More so than a Holley Style carburetor !!! IT CAN BE DONE !!! If you have $8000( My friend wants to buy one for his Subaru) to buy an Aftermarket ECU for your fuel management by all means go for it to each their own ! 🤷‍♂️

What about the fact the efi bodies don’t run chokes and the Webber do run chokes, did you think the over all size of the throttle Bodie bore where too Leigh in diameter , Been here done this! Been a engine builder/ tuner for a very long time, car engines and bike engines, fuel control via efi is always better, you just need to make sure your intake air speed is correct for the engine, the fact you needed to speed up the air flow with the carby ram tubes is telling me , with the chokes in the carby increasing air speed, the throttle bodies bore size was too big. After all this is a street car with a small cam, I have the best results by choking Webbers down to 38mm and seen power losses when going to Webber style throttle bodies cause of the slower air speed due to larger bore size

great video by the way, keep up the good work

the most interesting part, how much stronger did the engine get? its torque that matters

I don't see a problem with running different trumpets with the efi compared with the carbs. That's all part of it. Each system needs its own special parts and equipment. It would be a bit like saying we will run fuel injection but we won't use injectors because the carbs don't have them. That's silly, each system has its own parts it needs that will be different to the other system. If the combination of parts in the injection system gives you more power or it drives more to your liking, then that is the superior system for you and whatever combination of parts it consists of works for you.

Very hi psi injection via fuel pumps and injection can make a increase in Hp. Very costly for a top notch system. A cold air box on that application would also pick up around 10 or so Hp

Good on you. Thanks

Would have been interesting to see what happened with the throttle bodies spaced off the head

Much difference in fuel economy?

That’s not fair 🦣🦓🐆🦒

Very interesting video. But have to ask, the car is very similar to the Opel Ascona A here in Europe, is it the same?

Charge cooling from carbs. You're getting the effect of phase change in the Venturi since at WOT Venturi vacuum is inversely proportional to manifold pressure. In this low depression the fuel tends to boil due to pressure drop around the boosters. There isn't really enough time for it to properly boil per se because manifold pressure = atmospheric pressure at WOT (minus air cleaner restriction but close enough) the constant phase change in the Venturi area is having an effect on power by increasing air density slightly. In injection systems the fuel is injected but the system doesn't require a Venturi, but it seems you've compensated by playing with ram tubes positively varying volumetric efficiency.

Good test , thanks for doing it , I have a turbo EFI car and a turbo blow through carb car , no problems with either of them.

Good video and I like the car (I had an LC with a 202 at 11:1 on 36/72 with triple SU), it serves as a good reminder of what we used to know when aftermarket EFI was hitting the streets with Holley throttle bodies, that the main difference is you don't have to retune EFI every time you change elevation. A perfectly tuned multiple carb setup on dialled runners for the throttle response is basically the same performance as multiport EFI on the same ignition, except you have to pull over and retune if you drive up or down a mountain or lose power with altitude change. Seasonal weather too. Basically I had to retune the SUs and reset the valve lash every second weekend plus whenever I changed elevation, which was the difference between beating or losing to a Brockie. Different story but the same my now ride is an 80s Merc six with a big cam and that was on K-jet, tried a franken standalone but couldn't reconcile the Bosch system so that's getting EFI now. On the milder cam though you wouldn't have got any benefit, the K-jet is a remarkably adaptive closed loop for a narrow band, being a vacuum system, it'll self adjust and auto-retune for any mods you throw at it until you do significant valve overlap, then it goes haywire. For a mild power build K-jet is better than EFI with barely any sensors, no wonder Porsche and Ferrari used it.

EFI is great. The only thing that stopped me going EFI over my twin (a million hours to tune) webers is that I wanted to keep my car true(ish) to its 1970’s heritage. I already have modern EFI cars and I find the webers quite fun from an enthusiast aspect.

I do and I dont miss my LC, it was a 192 with tripples, when the SB barina GSI came out, it absolutely distoryed the LC lol Plus all the 12'a and 13b's went turbo, so I had no hope racing them anymore. Then i started playing with the 1986 60 series Landcruiser.12Ĥ-T diesel 250hprwhp and 650 NM of torque lol

Where did you get the wig from I need one :) Top vid by the way

no air cleaners?

nice fair comparison

Hi mate, I'm running triple 45mm webers. I'm interested in what you have done with the computer ignition set up, and also the throttle linkage. Can I get some help or info please

What model Haltec is that running ?

Good test. Have you ever heard of Keith Frank? He makes a replacement emulation tube that works on a totally different operating principle. He calls them Venturi Pump Tubes, or VP tubes. He is not great at marketing but i really want someone like you, with a dyno and weber ecperience to check them out. He also makes a bunch of other trick parts like idle jets with adjustable air bleeds.

Its interesting i have always had the thought EFI injectors were an odd design very clumsy when you consider the better part of 60 70 years of development went into carb design and we arrived at a Venturi to deliver fuel at the ideal position in the intake stream with little fuel Pressure (relative) Why move it and redesign the wheel then try to compensate with higher injection pressures Why not retool the carb body and use the efi injector to metre the fuel to the Venturi then you get the best of both worlds

Joes the best

Is that the customer who is banned from many workshops / machine shops in Sydney because he just hangs around like a bad smell? I think i met him at Dominator Engines one day

I always found carbies made more peak power then efi. I always put it down to better atomisation with a carburettor

Really good test. I think to make it better you could get someone to 3d print some new velocity stacks with an identical bell mouth profile and length to the webers big with a flange for the jenvey bodies.

Have you tried an Aussie Rotec ITB?

Great video and very informative. Thanks for sharing your knowledge with us minions.

Thank you for ALL your honest and easy to understand results with this test. I am just about to update from a 32/36 Weber (which has been running super rich) on my 1966 1500cc Isuzu Bellett to a 38/38 Retroject EFI Throttle body and Autronic ECU.....this is a great insight to the fact it is NOT going to make it into a horsepower monster. All I am trying to achieve is better acceleration and driveability, as currently it is a slug off the line. I am also aiming to turbocharge it next year to get just a little bit more get up and go. Thanks.

Great video gents.

Presents a lot of good points. I think you missed mentioning one of the key benefits, much cleaner emissions.