anyone put motorbike carbs on a car engine?

[petergoudie]

Use Su carbs. Cheap & plenty of spares and adjustment parts

[pandaah]

i would of chose 1400cc carbs for the 1.5 ltr d15 honda motor they were gunna go on, cant always jet them up from there least there not too far away from the mark, could only imagine the torquey response and air velocity would be a weapon..

was gunna be a project for me and my brother but he lost interest and so did i..

[George]

Sorry for the offtopic but why not consider EFI & chokes? I believe that this option require the same effort as multiple carbs. While the latter are quicker fit, efi is easier to get running really good and properly (afr, idle speed, cold starting just to point a few). You would also get better compromise between low rpm torque and high rev power. To my mind carbs are only good as a matter of style.

[ReQuieM]

The 'ITB' part of using the motorbike carbs is just a bonus. The carbs I was looking at offered something else I needed and a couple hundred cheaper. I've just brought a set of 4, and have my eye on another set. I'll try to remember to report back in once it's complete, which is admittedly a while away.

Bill because you have pm disabled I can't contact you with a could of questions regarding your setup, also you site requests no car related emails. So I'll just ask that if your interested/ able to help out with a couple of small questions I'd be really greatful.

[WDE_BDY]

Sorry for the offtopic but why not consider EFI & chokes? I believe that this option require the same effort as multiple carbs. While the latter are quicker fit, efi is easier to get running really good and properly (afr, idle speed, cold starting just to point a few). You would also get better compromise between low rpm torque and high rev power. To my mind carbs are only good as a matter of style.

Cost can be a significant factor, while the throttles are cheaper the computer to run it is not. Having said that I am currently investigating 2 sets of Honda VFR800 throttles for my V series V8. Generally the bike throttlles will run a much bigger engine than standard if the revs are dropped so overall air volume demand is similar. Say Hyabussa throttles will run a 2L engine as they will probably only see 7,000rpm compared to well over 10,000rpm on the bike.

Callum

[ReQuieM]

Yup, also my setup is going into a vintage vehicle so being somewhat period correct is a consideration of mine, altho the carbs are from an early 80's bike. A lot of old race cars (probably more amateur league) used to run bike carbs, so there is a precedent for it.

Finding the CFM capacity of a bike carb is a hard thing to achieve tho. I'm going by throat size as a ball park guide. I know its not that great of an idea but its about the thing I can go on atm.

[Billzilla]

Bill because you have pm disabled I can't contact you with a could of questions regarding your setup, also you site requests no car related emails. So I'll just ask that if your interested/ able to help out with a couple of small questions I'd be really greatful.

Go ahead and email, I'll try to reply in less than a month.

[smiley_666]

Finding the CFM capacity of a bike carb is a hard thing to achieve tho. I'm going by throat size as a ball park guide. I know its not that great of an idea but its about the thing I can go on atm.

the thing you have to remember about bike carbs is that most dont have a "choke" like webbers etc. - they are a CV type of carb.
most larger bike carbs will work - zx9r, R1, bigger CBRs etc. usually you can just block off the air jets and drill out the main jets.

also, most bike carbs run on 3psi fuel pressure. lots use the bike fuel pump mounted in the engine bay (they die pretty quickly when used for 'pushing' fuel)

[Billzilla]

also, most bike carbs run on less than 1 psi fuel pressure. lots use gravity feed from the tank to the carbies

Fixed.
The carbies I use (Mikinu flat-slides) need 0.7 psi, as do many others.

[smiley_666]

well, the ones with electronic fuel pumps run on 3psi.

[boxh34d]

Yup, also my setup is going into a vintage vehicle so being somewhat period correct is a consideration of mine, altho the carbs are from an early 80's bike. A lot of old race cars (probably more amateur league) used to run bike carbs, so there is a precedent for it.

Finding the CFM capacity of a bike carb is a hard thing to achieve tho. I'm going by throat size as a ball park guide. I know its not that great of an idea but its about the thing I can go on atm.

If CFM figures are hard to come by, can you not just try and match HP output. X amount of power basically requires Y amount of air. If quad carbs can supply enough air for 200hp on a bike, then they should do for around 200hp on a car engine - irrespective of RPM or engine capacity. Some differences due to efficiencies and cams etc, but it should give you a good general idea as a starting point.

[Billzilla]

well, the ones with electronic fuel pumps run on 3psi.

How many carby bikes ran pumps? I haven't seen a lot of carby bikes but so far none of them had a pump. They're pretty thin on the ground these days as well due to emissions regulations and so on.
I think my VTR1000 is probably one of the last with carbies.

[smiley_666]

lots of them did. the R1s, zx9r, zx6r, a few of the cbr's all ran fuel pumps. (the most commonly used carbs for cars)
it all depends on the bike. if it had an electric fuel pump it runs on 3psi fuel. if it didnt have one it will need miniscule pressure

[Shifty]

Bill, once this 18R/Hilux thing is done I'm still keen on the G13B setup we were talking about. If you happen to become learned about turbo setups on them at all, I'd be interested to know. turbo isn't my ideal route but a stressed 160hp vs a lazy 200rwhp starts to become an easy decision.

I'm thinking that turbo is a good way to achieve 200hp without really adding any extra weight or a lot of cost.

ANYWAY back on topic.

I'm shortly starting to adapt bike EFI to a car engine (EFI setup should be sitting in my doorstep today!) but personally I wouldn't bother with carburettor swaps but some of the later big-bore bikes have high resolution and reasonably-sized injectors. The beauty with EFI is you have stand-alone management for ease of tuning, whereas with carbs they are much more sersitive to variances in vacuum, fuel pressure, etc.

pandaah - starting to sound with vacuum reservoirs & pumps etc that this is way more complex than any performance/uniqueness aspect would warrant.

[Shifty]

If CFM figures are hard to come by, can you not just try and match HP output. X amount of power basically requires Y amount of air. If quad carbs can supply enough air for 200hp on a bike, then they should do for around 200hp on a car engine - irrespective of RPM or engine capacity. Some differences due to efficiencies and cams etc, but it should give you a good general idea as a starting point.

spot on mate