Great if it all works out, the first set of bike carbs we tried didn’t work, we wasted days on them . Eventually they were sorted and will be coming in another video
@@PenguinMotors they work brilliantly and better than any webers I ever had on my old Alfas,, but they do take a bit of work and a wideband to get them right
Yes, the Mikuni´s definitely need longer stacks. It is actually quite visible in the lower rpms. The fuel stand off is not getting caught back up, also the intake length is too short which increases the dip in the torque curve in spite of the 4-2-1 header. That said, they will most likely still loose to the 45´s with 38 venturies, but there is a good chance that the torque pattern will be even better than with the Webers. (Not more, just better)
i think the thing missing here is that the bike carbs are optimised to work with an air box or plenum if you prefer, in my experience they fuel much better than either 40's or a 32/36 especially when balanced properly
Great test Graham. I'd call that a win for the Webers, and if you bring 'style' into the equation nothing beats the look of a pair of DCOEs on a crossflow/pinto. Have a similar setup to this in the Capri and you've just reiterated how badly I need to swap out my 36 chokes for 38s!!
It doesn’t show up as horsepower on the dyno but the smaller chokes allow you to hit the throttle harder faster lower down on the Rev range. I’ve got at set of 37,s to try sometime
Coming from the motorcycle tuning world, I would say, fitting an airbox much like you see on a motorcycle those carbs came off, making volume of the box the same and the air intake snorkel similar, you would see more power for less fuel used. The other point here is notice the reversion on the bike carbs, most of that is being lost , where as with the Webber less is lost due to the length of the ram tubes, ease of tuning, I would also give that to the bike carbs and the cost and availability again to the bike carbs, Your old school it seems, still doing stuff I was doing in the 1980s, some of us evolve and adapt while others are left back in the 1980s, never learning the secrets of good airbox design . Maybe it was my time around dyno tuning race bike engines and race car engines . I am trying to get into your channel, but it’s like the rocky horror picture show! Stuck in a time warp. 1992 I had a datsun 1600 with a z18et making 400 rwhp with a basic screw driver adjustable microtec ecu , garret turbo and a front mount intercooler. It made well over double the hp my previous engine did and used half the fuel and was a reliable every day car, in like that temperamental Webber & camed L20b . It opened my eyes to technology . Made my career jump all over those dinosaurs that would not advance past the carbs.
You only see what’s on the channel, my own race car and a number of my customers cars run modern engine management systems. It’s just the Old Ford world is mostly stuck in the 1980’s so that’s where the real interest with my viewers is.
The carb piston wasn’t lifting fully at lower / middle rev range it was fluttering on number 1 cylinder. The power curves are much of a muchness until 5500+rpm in reality unless the car is being used on a track the benefits of bigger chokes will seldom be used. Do the bike carbs suffer as they’re only being used at 50% of their delivery capacity (12,000rpm)? Viewers may find it interesting to see some runs in low or no light, it’s informative to see an exhaust manifold under full load.
theoretically just like an SU carb the piston shouldn't be fully up until the top of the rev range, true a pinto is only reving to half the rpm of a bike engine, but its twice the size which should offset the lower revs
Need to setup the bike carbs better, the slides should be lifting according to vacuum demand. At the start of the pull they were almost up all the way, that's why your torque suffered and why you can see them flutter so much. When correct they'll "hum" looking almost stationary and how they open will be almost linear from idle (fully down) to redline (fully raised). You'll need to play with different springs to adjust the slide behavior better (currently too weak), you're lucky you can sit in the dyno with a camera because fine tuning vacuum slides in a machine with only the open road as your test bed is a pain in the rear. Also need more time syncing the carbs and tweaking the engine to allow that, #2 slide lifts erratically compared to #1 before the pull.
I used what I had, but I think the comparison was reasonable, the bike carbs fell in between the two different choke sizes of the Webers, so we actually compared a commonly used bike carb against 2 commonly used weber set ups. But what ever way you look at it a comparison between two totally different carb and manifold setups is never going to be apples to apples
Such carburettors taken straight from the motorcycle need an airbox with an air filter because without it they get too much air and the engine will not have the correct torque curve. I service such motorcycles and I have noticed many times that without an airbox the engine is reluctant to rev up. This carbs was manufactured to work with an airbox of the right volume with an intake hole of the right diameter
Maybe. I’m not sure that motor would of given even more power, what I was actually doing was evaluating the bike carbs for the clients engine, I just used my Webers to run the engine in an get a baseline power figure.
I enjoyed watching this, but as an old fart who has been testing engines since 1964 ...... I don't actually get the point! All this testing was done at Wide Open Throttle (WOT) which is OK. With any fuelling system you can put in the right amount of fuel for maximum power. The carburation variables that effect power and torque are the diameter and length of the intake tract and any restrictions along the way. To make a meaningful comparison between Webers and Mikunis, as far as max power is concerned, it would be necessary to test all carb / choke sizes and all inlet tract lengths on both systems. In my experience the difference between the two optimised systems would be insignificant. For anything other than race applications what would be far more important would be driveability and fuel consumption. In that comparison I suspect that the Webers would win hands down (Assuming that in both cases the carbs were expertly optimised). (Smiley face).
These videos are not really meant to be the be all and end all and definitive testing of all the options. To do that would cost an absolute fortune and take forever and you got to ask who would pay? I get asked a lot about what sort of power differences there are between various setups all I’m doing is giving a light hearted insight.
I had a 74 celica with a 1750 12/1 Toyota 2t engine , fully ported big valve engine. I used zzr1100 carbs. Couldn’t flow enough fuel over 6000rpm made 130 bhp. I had the air correctors blocked and all sorts to try to get them good, and being a bike mechanic, I know my way Around a set. Would be ok on a lower output engine The bike made 125 ish originally, but with more revs and smaller cylinders. Bike carbs are for bikes , small cylinders high rpm. I think I’d have had more luck with bike throttles and an ecu but the car got knicked
If you ask my opinion the best place for bike carbs are on bikes! yes They can be made to work well on a pinto but its not always the walk in the park everyone thinks. i personnal wouldnt be swapping 40 DCOEs for bike carbs even if there was a bit of a power gain. if you want more power 45 dcoe are the answer
Thank you for your response was thinking of it cause I'm in the process of rebuilding a pinto using your guidance in your videos but the dcoe prices where I'm from are not reasonable
@@PenguinMotors Pfft. I bought a parts motorcycle for $50. It came with 4 Mikunis. How much those DCOEs and manifold cost you? Plus, They don't even make a manifold to use with DCOEs for my old Toyota.
hi after seeing most of your vid`s on the 2lt pinto the brisca f2 stock car boy`s recone thay get 150bhp from thare slightly tuned pinto running a twin chocke weber i find that hard to believe now [ wat bhp do you think there running ? ]. if your engine`s are running say 130 bhp on the dyno wat do you think you lose through the g/box , dif [ real BHP at the wheel`s ]
the F2 boys use a pretty hairy cam plenty of compressin and limited head mods. Having run an F2 cam i would say a good one would scrape 150bhp, with a pretty nasty power delievery completely unsuited to road use. you say real bhp at the wheels, you know you can change that by simply changing tyre pressures? its also different whether you have a twin or single roller rolling road, add in a few other variables whats real?
@@PenguinMotors thank`s for that reply , just confuse us a bit more i run a mazde 6 mps in british trim a good std engine is said to do 256 bhp but on a rolling road dyno it get`s to 210 bhp that`s a loose of 46 bhp i know it going through a gearbox , active diff , 4 wheel drive system , 4 tyre`s but to me in this day and age with good machining that seem`s like a big loose ? . iv done a bit of work on my engine and on the rolling road it hit 254 bhp running slighty lean at high rpm [ might hav it remaped for the AFR ] so to me that engine should make 300 bhp ? , a guy in the STATE`S has spent a lot of money on his engine and it`s running 800 bhp at the wheel`s
@@PenguinMotors I have also always used RL31 with forged pistons but all was rally engines with 11:1 or little higher CR, if I remember correctly up to 11,5:1 CR. Some RL31 grinds seem to be different than others over the time and producing less dynamic CR
I've got 38mm mikunis on my Zetec 2.0. The massive advantage over Webers is they cost £25.
Great if it all works out, the first set of bike carbs we tried didn’t work, we wasted days on them . Eventually they were sorted and will be coming in another video
@@PenguinMotors they work brilliantly and better than any webers I ever had on my old Alfas,, but they do take a bit of work and a wideband to get them right
Yes, the Mikuni´s definitely need longer stacks. It is actually quite visible in the lower rpms. The fuel stand off is not getting caught back up, also the intake length is too short which increases the dip in the torque curve in spite of the 4-2-1 header. That said, they will most likely still loose to the 45´s with 38 venturies, but there is a good chance that the torque pattern will be even better than with the Webers. (Not more, just better)
Would be great if you could try 40-42mm bike carbs.
There might be something to be gained by experimenting with longer tubing or intake between the bike carbs and motor, might smooth out the torque
Exactly this, pointless test without testing all equal, including inlet tract length.
Excellent channel, pure noise and old skool engines :)
It's weird but watching that Pinto rev I can smell the engine.
Sure brings back memories of the Cortina era
i think the thing missing here is that the bike carbs are optimised to work with an air box or plenum if you prefer, in my experience they fuel much better than either 40's or a 32/36 especially when balanced properly
I know from my bike days that bike carbs do not like having there original factory air boxes messed with or removed.
Great test Graham. I'd call that a win for the Webers, and if you bring 'style' into the equation nothing beats the look of a pair of DCOEs on a crossflow/pinto. Have a similar setup to this in the Capri and you've just reiterated how badly I need to swap out my 36 chokes for 38s!!
It doesn’t show up as horsepower on the dyno but the smaller chokes allow you to hit the throttle harder faster lower down on the Rev range. I’ve got at set of 37,s to try sometime
@@PenguinMotors Always a trade off! Tempted to try it given the increase in torque/hp. Will report back.
I never did mess with bike carbs , nice result and the webers look the part now dont they !
Bike carbs looks to have shorter intake runner length. I wonder if runner extension on bike carbs would improve the torque curve.
it probably would
I'd like to see some kehin fcr,s tested instead of CV bike carbs
Bike carbs need ram pipes to create vacuum over pistons an work well and smoother!!!
These had there original factory ram pipes, what the didn’t have was there air box which is what they really want
Coming from the motorcycle tuning world, I would say, fitting an airbox much like you see on a motorcycle those carbs came off, making volume of the box the same and the air intake snorkel similar, you would see more power for less fuel used. The other point here is notice the reversion on the bike carbs, most of that is being lost , where as with the Webber less is lost due to the length of the ram tubes, ease of tuning, I would also give that to the bike carbs and the cost and availability again to the bike carbs, Your old school it seems, still doing stuff I was doing in the 1980s, some of us evolve and adapt while others are left back in the 1980s, never learning the secrets of good airbox design . Maybe it was my time around dyno tuning race bike engines and race car engines . I am trying to get into your channel, but it’s like the rocky horror picture show! Stuck in a time warp. 1992 I had a datsun 1600 with a z18et making 400 rwhp with a basic screw driver adjustable microtec ecu , garret turbo and a front mount intercooler. It made well over double the hp my previous engine did and used half the fuel and was a reliable every day car, in like that temperamental Webber & camed L20b . It opened my eyes to technology .
Made my career jump all over those dinosaurs that would not advance past the carbs.
You only see what’s on the channel, my own race car and a number of my customers cars run modern engine management systems. It’s just the Old Ford world is mostly stuck in the 1980’s so that’s where the real interest with my viewers is.
Would be interesting to see the fueling graph on the bike carbs, they didn’t look happy low down.
They weren’t overly happy low down but then again the engine had a cam that isn’t suited to full throttle running low down.
This is the best video I've been wondering
The carb piston wasn’t lifting fully at lower / middle rev range it was fluttering on number 1 cylinder. The power curves are much of a muchness until 5500+rpm in reality unless the car is being used on a track the benefits of bigger chokes will seldom be used. Do the bike carbs suffer as they’re only being used at 50% of their delivery capacity (12,000rpm)?
Viewers may find it interesting to see some runs in low or no light, it’s informative to see an exhaust manifold under full load.
theoretically just like an SU carb the piston shouldn't be fully up until the top of the rev range, true a pinto is only reving to half the rpm of a bike engine, but its twice the size which should offset the lower revs
Need to setup the bike carbs better, the slides should be lifting according to vacuum demand. At the start of the pull they were almost up all the way, that's why your torque suffered and why you can see them flutter so much. When correct they'll "hum" looking almost stationary and how they open will be almost linear from idle (fully down) to redline (fully raised). You'll need to play with different springs to adjust the slide behavior better (currently too weak), you're lucky you can sit in the dyno with a camera because fine tuning vacuum slides in a machine with only the open road as your test bed is a pain in the rear.
Also need more time syncing the carbs and tweaking the engine to allow that, #2 slide lifts erratically compared to #1 before the pull.
you make a lot of interesting points, the only thing i can add here is the carbs were supposed to be plug and play!
Good stuff 👍
Shame you didn't use the 40mm R1 carbs as a proper comparison as the 38mm ones are just too small to compare apples to apples
I used what I had, but I think the comparison was reasonable, the bike carbs fell in between the two different choke sizes of the Webers, so we actually compared a commonly used bike carb against 2 commonly used weber set ups. But what ever way you look at it a comparison between two totally different carb and manifold setups is never going to be apples to apples
@@PenguinMotors I think you're right. Thanks for posting the vids. Keep up the great work
Something was playing up on the cylinder 1 bike carb.
Such carburettors taken straight from the motorcycle need an airbox with an air filter because without it they get too much air and the engine will not have the correct torque curve. I service such motorcycles and I have noticed many times that without an airbox the engine is reluctant to rev up. This carbs was manufactured to work with an airbox of the right volume with an intake hole of the right diameter
Yes I’m well aware of that, these carbs belonged to the client and were supposed to of been modified to suit the application
you had the opportunity there to stick 40mm chokes in and see even more top end !!
Maybe. I’m not sure that motor would of given even more power, what I was actually doing was evaluating the bike carbs for the clients engine, I just used my Webers to run the engine in an get a baseline power figure.
He lives for his catchphrase 😁
It came about by accident, my wife hates it, I’m bored by it, but I get complaints when I leave it out!
@@PenguinMotors can’t please all the people all the time
i swapped zx9 carbs out for delorto 40's on the pinto. whoops
I enjoyed watching this, but as an old fart who has been testing engines since 1964 ...... I don't actually get the point! All this testing was done at Wide Open Throttle (WOT) which is OK. With any fuelling system you can put in the right amount of fuel for maximum power. The carburation variables that effect power and torque are the diameter and length of the intake tract and any restrictions along the way. To make a meaningful comparison between Webers and Mikunis, as far as max power is concerned, it would be necessary to test all carb / choke sizes and all inlet tract lengths on both systems. In my experience the difference between the two optimised systems would be insignificant. For anything other than race applications what would be far more important would be driveability and fuel consumption. In that comparison I suspect that the Webers would win hands down (Assuming that in both cases the carbs were expertly optimised). (Smiley face).
These videos are not really meant to be the be all and end all and definitive testing of all the options. To do that would cost an absolute fortune and take forever and you got to ask who would pay? I get asked a lot about what sort of power differences there are between various setups all I’m doing is giving a light hearted insight.
I had a 74 celica with a 1750 12/1 Toyota 2t engine , fully ported big valve engine. I used zzr1100 carbs. Couldn’t flow enough fuel over 6000rpm made 130 bhp. I had the air correctors blocked and all sorts to try to get them good, and being a bike mechanic, I know my way Around a set. Would be ok on a lower output engine
The bike made 125 ish originally, but with more revs and smaller cylinders.
Bike carbs are for bikes , small cylinders high rpm.
I think I’d have had more luck with bike throttles and an ecu but the car got knicked
The bike carbs you put like 5 cm (its a metric engine😉) closer to the head. THAT'S where you loose your torq.
means the longer the runner, the better for torque range?
What would be the best set of bike carbs for the pinto engine and you say it will be better than 40dcoes.what jetting does it need?
If you ask my opinion the best place for bike carbs are on bikes! yes They can be made to work well on a pinto but its not always the walk in the park everyone thinks. i personnal wouldnt be swapping 40 DCOEs for bike carbs even if there was a bit of a power gain. if you want more power 45 dcoe are the answer
Thank you for your response was thinking of it cause I'm in the process of rebuilding a pinto using your guidance in your videos but the dcoe prices where I'm from are not reasonable
@@PenguinMotors Pfft. I bought a parts motorcycle for $50. It came with 4 Mikunis. How much those DCOEs and manifold cost you? Plus, They don't even make a manifold to use with DCOEs for my old Toyota.
Hello there
I want to bike carb my 2.4 22re using a smart carburetor will 40mm be enough?
Don’t know what a 2.4 22re is, what is a smart carburettor? If you are using one carb per cylinder it probably could work ok
Which are the specs on that engine, cr, cams, bore and stroke??
I didnt build it so i dont know all the details, this is what i do know. 93mm bore, standard 76.9 stroke, cam was kent rl31, cr was about 10.6
hi after seeing most of your vid`s on the 2lt pinto the brisca f2 stock car boy`s recone thay get 150bhp from thare slightly tuned pinto running a twin chocke weber i find that hard to believe now [ wat bhp do you think there running ? ]. if your engine`s are running say 130 bhp on the dyno wat do you think you lose through the g/box , dif [ real BHP at the wheel`s ]
the F2 boys use a pretty hairy cam plenty of compressin and limited head mods. Having run an F2 cam i would say a good one would scrape 150bhp, with a pretty nasty power delievery completely unsuited to road use. you say real bhp at the wheels, you know you can change that by simply changing tyre pressures? its also different whether you have a twin or single roller rolling road, add in a few other variables whats real?
@@PenguinMotors thank`s for that reply , just confuse us a bit more i run a mazde 6 mps in british trim a good std engine is said to do 256 bhp but on a rolling road dyno it get`s to 210 bhp that`s a loose of 46 bhp i know it going through a gearbox , active diff , 4 wheel drive system , 4 tyre`s but to me in this day and age with good machining that seem`s like a big loose ? . iv done a bit of work on my engine and on the rolling road it hit 254 bhp running slighty lean at high rpm [ might hav it remaped for the AFR ] so to me that engine should make 300 bhp ? , a guy in the STATE`S has spent a lot of money on his engine and it`s running 800 bhp at the wheel`s
What's the difference in price ?
Hi i want to know more . About swap from inyectores to weber on vw jetta mk4 2.0 8V.
Hi Graham, what was the CR on this RL31 engine ?
Im told its 10.65, and have no reason to doubt it, but i have never actually measured it
@@PenguinMotors thank you very much for your kind reply Graham. I imagine RL31 could do with a bit more CR, up to max 11.2-3:1, couldn’t it ?
i using go with around 11.1 or a little more, but not on an engine with cast pistons
@@PenguinMotors I have also always used RL31 with forged pistons but all was rally engines with 11:1 or little higher CR, if I remember correctly up to 11,5:1 CR. Some RL31 grinds seem to be different than others over the time and producing less dynamic CR
try with 4 carbs keihin fcr and you ll see