How could i get more, bearing in mind i dont have the carbs yet? I am considering some on a 1.3 mkII though, but have heard you dont get much low down power. Supercharging is an option

Sorry if this isa repost, but i haven't seen anything addressing this particular issue

Opinions more than welcome

H&S

Super charging is an option but an expensive one. Bike carbs will give you more power everywhere if set up properly with complementary mods.

Could get a bigger cc bottom end, ABD. Or a complete bigger engine if you are worried about torque. AEEs 1600's give VERY good torque and fit right in.

Super charging is an option but an expensive one. Bike carbs will give you more power everywhere if set up properly with complementary mods.

Could get a bigger cc bottom end, ABD. Or a complete bigger engine if you are worried about torque. AEEs 1600's give VERY good torque and fit right in.

The cost isnt of too much of a worry (not that i have loads of money!) since its either this or a g40 eaton. I like the idea of the build challenge though tbh. Plus i have the basic engine already. Any engine i get i will rebuild anyhow, so if I'm going to do the work, i want something fun at the end of it (not that an eaton wouldnt be fun!)

How do you mean complimentary mods? I was thinking GT inlet myself (more torquey right?)

Why do you say it would be expensive?

H&S

Surely if you are running bike carbs you wont be using a GT inlet?

Complimentary mods such as 4 branch, chip (if you are using standard management), cams, etc I'm guessing..

umm well if money is no issue, i'd be looking at (well i wouldn't, but the options are) a high spec g40

Or a very worked AEE with twin 40's

Or a very worked AFH (1.4 16v), 1.6 16v (don't know the code) with twin40's

Depends what you want from it really...

45s on an AFH for reference....and the twin weber manifold is super rare.

Surely if you are running bike carbs you wont be using a GT inlet?

Complimentary mods such as 4 branch, chip (if you are using standard management), cams, etc I'm guessing..

Since i'm considering a supercharger, i was going to use the GT inlet, bolt charger to that, and then attatch bike carbs somehow

Not too interested in twin 40's. though i said money was no option, these can be a little pricey. Its not as if i have unlimited funds, so maybe i should have said money is not a restriction, within reason.

And high spec G40 sounds nice, but i want to do the work myself, i'm kind of set on bike carbs now, after doing the research. Also, i have 2 spare engines that need something doing to them!

Oh, and its a carb engine, so no ECU, making things much easier!

Cheers guys, keep it coming!

H&S

If you want more low down torque then bike carbs are not your answer, their venturis are to big

you could try a supercharger, but i doubt any of the bike carbs will be capable of handling boost without modification

sticking on a 4 branch manifold will NOT help either, in fact do the opposite

Standard road cars generate low down torque by having long inlet manifolds to increase entry air speed and emulsification, softer cam profiles to ensure a definite exchange of inlet/exhaust gases and also give the correct cylinder filling, narrow exhaust manifolds and small exhaust bores

but like twin40racer said, you won't get much low down torque from the 1.3 engine anyway. step up to 1.6 and you have more to play with and it will respond better

Thats what i thought with the bike carbs, there's no torque, just a lot of revs! I have been doing some investigation, and there are supercharger conversions for bikes, i even found one utilising an eaton!

Yeah, I'm aware as standard they dont generate too much. Since its an old engine, and the bores are probably oval now (!) i was considering a re-bore.

My ideas were; MH block and head, G40 pistons, Standard G40 cam (for the softer profile), GT Inlet, G-lader (or similar) charger with one large bike Carb (with a 40mm-ish choke). Probably change the valves for G40 ones too. I understand (especially after writing it there!) this looks like a G40 engine. Essentially, I'm looking for a way to supercharge an engine without faffing around with an ECU. So if there's an easier way, please, let me know!

Thanks for the input

H&S

rule of thumb wise (there are obviously rules to this exception)....

bigger bike carbs = power high up, smaller bike carbs = power lower down

short intake manifold = power high up, longer intake manifold = power lower down

and whilst what redroller said is VERY true for the most part, how can ALL bike carbs have to big venturis? surely you get carbs with venturis to compliment? ie bike carbs on a 2ltr pinto need around 36-38mm chokes so at a guess, a 1.3 might want 30-32mm chokes? there are table for deciding what webber DCOE's you need, these are a good way of working out what choke size you need. (note webber 45's don't have a 45 mm choke)

sorry if that sounds a bit muddled, i know what i mean but I'm having trouble wording it today!

you can also slightly tune the torque curve by using different lenght/diamter trumpers

rule of thumb wise (there are obviously rules to this exception)....

bigger bike carbs = power high up, smaller bike carbs = power lower down

short intake manifold = power high up, longer intake manifold = power lower down

and whilst what redroller said is VERY true for the most part, how can ALL bike carbs have to big venturis? surely you get carbs with venturis to compliment? ie bike carbs on a 2ltr pinto need around 36-38mm chokes so at a guess, a 1.3 might want 30-32mm chokes? there are table for deciding what webber DCOE's you need, these are a good way of working out what choke size you need. (note webber 45's don't have a 45 mm choke)

sorry if that sounds a bit muddled, i know what i mean but I'm having trouble wording it today!

you can also slightly tune the torque curve by using different lenght/diamter trumpers

No, that makes sense :-)

The reason i was going to go for a large choke was for the supercharger, as its obviously going to need more fuel right? And this is what the larger choke should allow.

Please correct me if i'm wrong

H&S

Not too interested in twin 40's. though i said money was no option, these can be a little pricey. Its not as if i have unlimited funds, so maybe i should have said money is not a restriction, within reason.

if twin webers are too expensive for you then you might as well stop thinking along the lines of superchagers too as that would work out a shit load more expensive

there was a photo posted on here ages ago where some one was trying to use bike carbs and a superchager together, never heard any thing else of it tho so guessing it didn't work. the thing is bike carbs ain't designed to have air forced into them so you'd probably just blow all the seals as soon as you tried to start it. although saying that some super bikes do get turbo's retro fitted to them (and a few fitted from the factory), maybe they use throttle bodys tho? i'm not sure but that could be an option for you? but you'd still need to run some kind of engine management i would of thought. the problem is cost, just buying all the parts and getting the engine built to take it is going to be very expensive, and that's before you add the cost of all custom fabrication and the cost of getting it set up and running right. even supercharging your engine using G40 parts would work out more expensive and probably less reliable than just fitting a G40 conversion.

also you would still need to run the G40 ecu on your engine to control fueling, what about using a carb off a R5GTT? then use the ignition off of a carbed polo? that would get rid of the need for an ECU, but you'd still have to get a inlet manifold fabricated to get it to fit on your engine. not sure how well that set up would work together tho, just thinking out loud...

Seems that in all this speculation,some people have completely lost sight of the fact that bike carbs are very good for high torque at low rpm.

Where people are going wrong is by imagining that the airflow through the carb is very slow at low rpm,and so the mixture is crap.

Wrong.

They are not 40's,they are a different design,and cannot be theorised in relation.

They have diaphram trailing throttles - inlet vacuum controlled flat slides that only allow fuel and air in of a volume that the engine can use,and the fuel outlet (plugged by a tapered needle,which is also controlled by the slider) is directly behind its opening. So even if i have the pedal on the carpet at 2k rpm in fifth gear,my carbs are not 36.5mm. They're only about 10-15mm. And the resulting high-speed air flow is firing directly at the fuel,causing the fuel to atomise into a fine spray form.

This is why bike carbs are still very efficient even when you've got your foot on the carpet all the time at low rpm - as long as they're set up properly.

Speculation aside,I've personally ran these carbs in a MK2 on a 1.4 8v,1.6 8v,(and 1.6 16v engine-only) - and the torque has been far more than the chassis can handle with both driving engines.

Midrange,i got wheelspin in fourth gear at approx 60mph with the 1.4.

At under 2k rpm i got wheelspin in third gear with the 1.6,first gear was utterly redundant,and it broke two gearboxes in 500 miles.

In both cases,the clutch was not being used - they just pulled out of traction. Traction at low rpm has always been an issue,though the 1.4 was far more useable - and usually more fun.

(The 16v is running,but it's not yet on the road. I have concerns that it'll be frustrating to drive).

Obviously a bike-carb'd 1.3 will not be comparable with a 'charged 1.3,and i doubt anyone would suggest so. But to suggest that low range torque is a bike carb weakness? Not just completely wrong but ironic,when i dont know of any other normally aspirated set-up that will give more on the same engine.

Seems that in all this speculation,some people have completely lost sight of the fact that bike carbs are very good for high torque at low rpm.

Where people are going wrong is by imagining that the airflow through the carb is very slow at low rpm,and so the mixture is crap.

Wrong.

They are not 40's,they are a different design,and cannot be theorised in relation.

They have diaphram trailing throttles - inlet vacuum controlled flat slides that only allow fuel and air in of a volume that the engine can use,and the fuel outlet (plugged by a tapered needle,which is also controlled by the slider) is directly behind its opening. So even if i have the pedal on the carpet at 2k rpm in fifth gear,my carbs are not 36.5mm. They're only about 10-15mm. And the resulting high-speed air flow is firing directly at the fuel,causing the fuel to atomise into a fine spray form.

This is why bike carbs are still very efficient even when you've got your foot on the carpet all the time at low rpm - as long as they're set up properly.

Speculation aside,I've personally ran these carbs in a MK2 on a 1.4 8v,1.6 8v,(and 1.6 16v engine-only) - and the torque has been far more than the chassis can handle with both driving engines.

Midrange,i got wheelspin in fourth gear at approx 60mph with the 1.4.

At under 2k rpm i got wheelspin in third gear with the 1.6,first gear was utterly redundant,and it broke two gearboxes in 500 miles.

In both cases,the clutch was not being used - they just pulled out of traction. Traction at low rpm has always been an issue,though the 1.4 was far more useable - and usually more fun.

(The 16v is running,but it's not yet on the road. I have concerns that it'll be frustrating to drive).

Obviously a bike-carb'd 1.3 will not be comparable with a 'charged 1.3,and i doubt anyone would suggest so. But to suggest that low range torque is a bike carb weakness? Not just completely wrong but ironic,when i dont know of any other normally aspirated set-up that will give more on the same engine.

Wicked. I wanted advice from people who have run the set up, so this is mist welcome. I ont want masses of torque, but i wasnt a usuable car, daily runner.

Still, would love to see someone who has charged one!

H&S

sticking on a 4 branch manifold will NOT help either, in fact do the opposite

Strange that, i have always known a well designed 4-2-1 to increase torque upto its maximum point along its rpm and then increase bhp after max torque. Longer headers and better collector designs

..I ont want masses of torque, but i wasnt a usuable car, daily runner.

A 1.3 will probably need a bit too much kicking for that.

The 1.4 8v ABD was a great daily,though.

Had a higher top speed than the 1.6,as it sat at higher revs in fifth. It sounded sweet,was smooth and flexible,quick enough,and very good on fuel.

A GT cam would make it more sporty,but the 1.4 16v AFH must be far better for that. Best person to ask would be Max_crox because he's running a bike carb'd AFH.

The 1.6 8v is more suited to a Golf,or driver who prefers using a lower rev-range. It does climb,but not so progressively,and whilst it will go to 6k there's not really any benefit in doing so,because you get more shove by changing up a gear by 5k.

..I ont want masses of torque, but i wasnt a usuable car, daily runner.

A 1.3 will probably need a bit too much kicking for that.

The 1.4 8v ABD was a great daily,though.

Had a higher top speed than the 1.6,as it sat at higher revs in fifth. It sounded sweet,was smooth and flexible,quick enough,and very good on fuel.

A GT cam would make it more sporty,but the 1.4 16v AFH must be far better for that. Best person to ask would be Max_crox because he's running a bike carb'd AFH.

The 1.6 8v is more suited to a Golf,or driver who prefers using a lower rev-range. It does climb,but not so progressively,and whilst it will go to 6k there's not really any benefit in doing so,because you get more shove by changing up a gear by 5k.

Where does the 1.6 or 1.4 come from? is it a straight drop in? And could it be carb'd and not need an ECU?

H&S

The 1.6 was the AEE engine from a 6n,and needed an engine mount adaptor made for it.

The 1.4 was the ABD from a MK3 Golf and bolted straight in.

The 1.6 16v is a hybrid,made of AFH/AEE/BCB parts and needed the engine mount adaptor.

All engines use/d carbs from a '00 Honda CBR600F-X. Starter motor and flywheel from an AFH/ABD. Electronic ignition system from an '88 Polo Coupe S.

Quick question to Mikey - you mentioned that a GT cam would make a 1.4 more sporty, so I'm assuming that a 268 style cam would make things even more sporty? Or would the overlap eliminate low down torque? (Which is what i'm experiencing now with Newman 270 cam in GT engine...)

I plan on carbing my GT at some point, but am waiting for a fair priced abd block to pop up...

sticking on a 4 branch manifold will NOT help either, in fact do the opposite

Strange that, i have always known a well designed 4-2-1 to increase torque upto its maximum point along its rpm and then increase bhp after max torque. Longer headers and better collector designs

i think what he is saying is by putting on most aftermarket 4-2-1's you move the torque band higher, so loose the low down torque, the bigger the primeries, the more this effect happens (it is to do with valve timing & gemoetry and all sorts of other complicated gas dynamics only found in engines)... this effect is even worse when using a 4-1 manifold!

and don't forget bhp is only a figure derived from a calculation of torque.... (torque [lbft] x RPM)/5252 so i don't know what you were trying to explain by increasing bhp after it reaches the max torque? And if when looking on a rolling road print our torque and bhp don't cross at 5252 rpm, someone is telling porkies!

forgot to say BIKE CARBS FTW!

cheap option over webbers (installing and running)

I have to say my Bike carbed AFH is an absolute rocket. Standard apart from the Lightened flywheel, SS manifold and exhaust and the bike carbs. I don't really know the torque or the BHP figure but I know its pulls away like a V8, stick it in any gear and there are no problems.

What I would highly recommend is getting them properly set up by people who know what they are doing and have the gear to do it. Mine ran fine from just putting the engine in an eyeing up the dizzy. Southam Mini & Metro Centre (quick plug there!!!) Re-jetted them and set the fueling and timing and it ran so much better.

tbh the power and torque that this engine is putting out is about as much as the chassis can handle. There is torque steer but its not too bad but its how it puts the power out that's just rather amazing. Its so liner and it just keeps going to way past 7000rpm.

Looking forward to a track day to see how it copes... I'm thinking an LSD might be next on the list but the engine will be staying as it it.

Quick question to Mikey - you mentioned that a GT cam would make a 1.4 more sporty, so I'm assuming that a 268 style cam would make things even more sporty? Or would the overlap eliminate low down torque? (Which is what i'm experiencing now with Newman 270 cam in GT engine...)

I plan on carbing my GT at some point, but am waiting for a fair priced abd block to pop up...

I dont have any experience with long-duration cams,but the GT cam has been used by others in the ABD and predictably the reports are that it livened it up a treat. Better induction only amplifies that.

How that particular engine (with its dimensions,close valve-piston margin and hydraulic tappets) responds to a cam cut for high rpm,i dont know. Other mods may be needed for it to deal with revs,or even just run without bending valves.

And you'll almost certainly loose some low down torque over the standard cam. You may even loose a touch with a GT cam.

You'll already know more than i do on all this because the ABD is the same engine as your GT but with a lower compression,milder cam and longer stroke.

Its likely to be a very sweet medium as a bike carb'd 1.4 ABD with GT cam though,i think its been done (Pete?),and maybe you should try both that and the standard cam first before deciding to spend hundreds on a higher-revving cam.

I have to say my Bike carbed AFH is an absolute rocket. Standard apart from the Lightened flywheel, SS manifold and exhaust and the bike carbs. I don't really know the torque or the BHP figure but I know its pulls away like a V8, stick it in any gear and there are no problems.

What I would highly recommend is getting them properly set up by people who know what they are doing and have the gear to do it. Mine ran fine from just putting the engine in an eyeing up the dizzy. Southam Mini & Metro Centre (quick plug there!!!) Re-jetted them and set the fueling and timing and it ran so much better.

tbh the power and torque that this engine is putting out is about as much as the chassis can handle. There is torque steer but its not too bad but its how it puts the power out that's just rather amazing. Its so liner and it just keeps going to way past 7000rpm.

Looking forward to a track day to see how it copes... I'm thinking an LSD might be next on the list but the engine will be staying as it it.

Really? How would it compare to say, a G40 accel wise? My bro has a bike engine in his LoCost. And that bastard pulls, like you say, right through the rev range. But thats a bike engine. I wasn't too sure how it would work on an engine, i wasnt aware of how popular it was! Theres a good place at silverstone down the road from me that i would take it to, i've heard they are good. Is a RR session what you'd recomend? When you say southam though, do you mean in Southam in Warks?

How long would you say it took you to put the bike carb set up on? If everything was ready to bolt on? Also, whats this SS manifold? That from bogg bros? I was thinking of making my own, with some silicone hose an top hat flanges, like some folks do. Would work aye?

H&S

Really? How would it compare to say, a G40 accel wise? My bro has a bike engine in his LoCost. And that bastard pulls, like you say, right through the rev range. But thats a bike engine. I wasn't too sure how it would work on an engine, i wasnt aware of how popular it was! Theres a good place at silverstone down the road from me that i would take it to, i've heard they are good. Is a RR session what you'd recomend? When you say southam though, do you mean in Southam in Warks?

How long would you say it took you to put the bike carb set up on? If everything was ready to bolt on? Also, whats this SS manifold? That from bogg bros? I was thinking of making my own, with some silicone hose an top hat flanges, like some folks do. Would work aye?

H&S

Well I've never been in a G40 but this is the same if not a bit quicker than a 200sx Turbo which have 200bhp and a 0-60 of 7.5secs.

Yeah a RR session is well recommended. I don't really have a clue when it comes to setting it al up but as I said it ran ok without any setup at all (perhaps I was just lucky). Yep Southam in Warks. I was pointed to them by Stealth Racing in Southam as people who have done bike carbs before and they are really top guys.

It takes no time to put the setup on as there isn't much to it at all. you need a electronic fuel pump and filter/regulator but other than that, plumb in it and bolt it on.

Sorry I meant a Stainless Steel exhaust Manifold, but the inlet manifold was made by Bogg Brothers and they did a strip and re-jet of the carbs as well.

Yes it would work but the only downside would be is that there will be bumps and the like in the inlet manifold where the hose joins the top-hats. If you can get the proper joining rubbers for the bike carbs these have recesses in them so once fitted there is a smooth flow through the whole of the inlet. I'm not sure it would make that much difference as many people do it the way you have said and it does work.

You can have a look at my build thread

My Build Thread as it has lots of info of what I've done.

sticking on a 4 branch manifold will NOT help either, in fact do the opposite

Strange that, i have always known a well designed 4-2-1 to increase torque upto its maximum point along its rpm and then increase bhp after max torque. Longer headers and better collector designs

i think what he is saying is by putting on most aftermarket 4-2-1's you move the torque band higher, so loose the low down torque, the bigger the primeries, the more this effect happens (it is to do with valve timing & gemoetry and all sorts of other complicated gas dynamics only found in engines)... this effect is even worse when using a 4-1 manifold!

and don't forget bhp is only a figure derived from a calculation of torque.... (torque [lbft] x RPM)/5252 so i don't know what you were trying to explain by increasing bhp after it reaches the max torque? And if when looking on a rolling road print our torque and bhp don't cross at 5252 rpm, someone is telling porkies!

I couldnt think of a good way to explain what i was trying to say, but its not what youve said here. More so that it helps to increase bhp after the car has reached its maximum torque. Something like that. Basically a good 4 branch is worth it imo

Couldnt agree more with a 4-1 type!