will the compression ratio not be fucked up by swapping the heads? although the bolt patterns are the same, they may have different decks... and you mention bike carbs and then turbo charging? I can agree with the bike carbs on a little 1L that revs it's nuts off, but when you turbo you would be best to get an injection throttle boddie to handle it... so the bike carbs will be rendered useless!

Not only that, but you will seriously need stronger pistons, rods, bolts and crank to handle turbo power, but not just that, decked pistons to lower the CR for the turbo, else your motor will just go bang! and that will cost shit loads!

Not only that, but once turbo'd, valve size isn't much of a factor as the air/petrol mix is forced in, not sucked through atmospheric pressure... so head wize don't matter, just the cam?

If you have addressed all thouse issues and have a competant solution to them, then good luck fella... i quite like a tiny screaming engine... but this sounds a bit optimistic?

ps. not here to criticise, just offer some advice before you embark on something that may end in tears!

fit bike carbs + elec fuel pump + regulator

GT Cam

GT exhaust manifold

GT Head

Home made 4-2-1

then i will think about electronic ignition, i know it doesnt add more power as such, but the way it delivers the power is much smoother

just had a re-read... what you are proposing here sounds like a good idea! I would suggest getting them all done at the same time, rather than one by one.... and leccy ignition would be a must, you are right about the fact it doesn't really add numbers to a bragging down the pub figure, but would really benefit a set up like this in the real world... especially since you are the adjusting timing and fuelling so much. make sure once it's all done you take it to a rolling road to be set up properly, else it will run like shhhiiiiiittttttt! and take spare jets as most car places won't stock bike jets

the reason for not doing them all at once is you will need to constantly re-set up every mod you make, do it in one go, all set up in one go... all working in harmony

don't go to big on the home made 4-2-1, you will loose power! no more than 1.25 inch primaries would be needed on an engine of this size, followed by about 1.5/1.75 secondaries and all collected in a 2 inch/2.25 inch exit?

good luck mate, should be a screamer!

Edited 4 March, 200917 yr by richie_stix

thanks for all the comments guys, the turbo would be in the future, i doubt the bike carbs would handle the boost without spraying petrol all over the engine bay

i think i mentioned earlier changing to some dellorto carbs when/if i turbo

the bore of the exhaust manifold would have been my next question, i'll probably go for the smallest possible to try and retain as much torque as i can, no point having the power but no torque!

as for whacking it all on at once, i dont like the idea, for 2 reasons

1) it will be my daily driver, i'll have the weekend and only the weekend to do whatever mods i have planned

2) if something doesnt work, if its the only thing i put on, i'll know straight away what it is, if i put it on all at once i will have a lot more fault finding to do!

polo d, you mentioned a swirl pot, how are you planning on plumbing this in, seems to be a lot of extra work when you can just route the excess fuel from the regulator back to the tank? the only reason i can think of for the swirl pot is to prevent fuel starvation during heavy cornering, but i doubt you'd need to worry about that too much unless you were building a track car?

Id keep the 1.0 head if your using it as a daily! The 1.3 head is simply to big for any sort of drivabitlity under 4000rpm.

Try a mix and match, use the valves off a 1.3 in a 1.0 head? Probably not ideal but seen as your giving evrything else a go

i'll probably end up buying a "spare" 1l head to play with, possibly even the whole engine, they seem to go cheap enough.

that way with a spare head to play with i can port/polish/ larger valves, skim it a bit to raise compression a little, that sorta thing, and dont have to panic if it all goes wrong

its all a bit of trial and error really, ideally i'd like to get it "breathing" nicely first, so inlet and exhaust system is the main priority, then once thats sorted i can try some larger valves, i dont want the fuel economy to suffer too badly so the inlet valves i dont want too big, so its just a case of finding the optimum balance between fun and funds

If you dont wanna go bike carbs why not try multipoint injection like on a gt.

Just use a smaller bore g40 inlet and port match the inlet to the head.

I'm sure someones done that before?

Edited 4 March, 200917 yr by shaun_89

fair enough, but what induction/fuel provider are you starting with... carb, injection what? you should only need a swirl pot if you are running injection, even then you can just block off the fuel return pipe on the bike carbs and fuel tank? loads of old skool ford owners run bike carbs with out a swirl pot, just the fuel pump from the bike?

i would make electronic ignition an early purchase as possible, as well as a timing light, that way as and when you make your mods, like carb and cams, you can at least re-time the ignition to suite at home

the size of the primaries on the exhaust manifold can 'tune' your powerband... basicly, the bigger you go, the further up the rev-range the power kicks in

a 1.3 head would only be worth while once the bike carbs are on and coupled with a GT cam i would think, as it would help produce the power better over the entire rev range, the larger posts/valves would then help flow all the extra fuel and air and be much more worth-while!

i wasn't planning on a swirl pot myself, was just interested as to why he's chosen to use one?

the bike carbs will go on first, electornic ignition will have to wait unless there is something similar to petronix that you guys use? its basicaly a switch that replaces the points, and is a hell of a lot cheaper than megajolt/megasquirt

once the fueling is sorted and running sweet i'll wait a few months while i collect parts for the rest of it, proably go either ignition or exhaust after

yeah, what i meant was something you convert the dizzy with.... akin to this http://www.hot-spark.com/

try H&H ignition, thats who i used for the dizzy on the capri... 125 +VAT, they refurbished and rebuilt my dizzy, and set the weights and advance to the spec of the engine and fitted their electronic ignition module!

megajolt and the like are crank sensor triggered ignition and use coil packs rather than the usual hight/low tension circuits! good luck mate, i will be very interested to see the results!

ps. primaries need to be roughly the same lenght on the exhuast side of things

yeah, fairly familiar with basic exhaust design, back pressure = torque

so the back pressure needs to be equal on all cylinders :)

the petronix stuff is this:

http://images.autopartsway.com/8wgv1rnk.jpg

it replaces the points in the stock dizzy with what is basicaly and electronic on/off switch, and at about £50 a go, if it works, it should be all good, much stronger spark (you need to upgrade the coil and leads) and no need to adjust points gaps as it doesnt wear down

hey man, just found this and I am going down a similar but slightly less ambitious route with a mk3 1 litre, I have sourced aload of GT parts and am gonna fit them to it. So far I've got-

GT Inlet mani with injector rail

GT Airbox

GT cam

GT wiring loom and ecu

All the vacuum hoses I need to get it running

just need a fuel pump and I'll have everythign I need to make it a 1 litre mpi.

The 1 litre block has a shorter stroke, so I am hoping that it will 0-60 on a par with a GT once all this is on, and I'm aiming for 65bhp.

Good luck with your project dude, and keep us posted.

sounds like you got it all planned out

good luck with the FI side of things, never got on with it myself, prefer a meaty set of carbs

65 bhp in a loon with full interior would give me a power to weight ratio of around 85:1 :D:D:D

good times

if i can get the weight down to 700kg the power to weight would be at 93:1,

better times

i would be happy with 65bhp, more would be better but i think it would start creeping into the realms of race only, i need to spend 2 hours in traffic 5 days a week

65-70bhp would be just about right

a power to weight ratio of 100:1 would be lovely

Sounds very interesting!!!!!! I'll be watching this.

I'm going for

- GT CAM

- 1.3/4 throttle body

- 1.3 manifold.

- 1.0 chip possibly

What power is possible from this do you think? 50-55bhp? sorry to steal your thread!

dont know to be honest mate, never had to deal with chips and ecu's and what not

can't say it enough that chips are a bit of a con! they have pre programmed computer data in them, how can that possibly match your exact engine? you need a piggy back chip/mappable ecu set up on the rollers

the CR ratio will also be higher in the 1.0, so more advance on the ignition = more power but you will need to run this sorta thing on higher octane fuel to stop the engine 'pinking'!

Edited 4 March, 200917 yr by richie_stix

can't say it enough that chips are a bit of a con! they have pre programmed computer data in them, how can that possibly match your exact engine? you need a piggy back chip/mappable ecu set up on the rollers

i dont fully agree there. most of these chips use a map that has been created when a similar car has been rolling roaded. in fact when a place like superchips do a car, they will use one of these maps as a base to start tweaking from. now seing as we are talking about small cc engine, your only gonna be missing out on a tiny amount of extra power, which simply isnt worth the expense of a rolling road and remap session.

if you were talking about big bhp forced induction cars then i would agree with you

I'm pretty sure all 1.0 are designed to run on the German grade fuel, 91ron.

So you could advance the ignition to suit our unleaded 95ron

polo d, you mentioned a swirl pot, how are you planning on plumbing this in, seems to be a lot of extra work when you can just route the excess fuel from the regulator back to the tank? the only reason i can think of for the swirl pot is to prevent fuel starvation during heavy cornering, but i doubt you'd need to worry about that too much unless you were building a track car?

well the only reason i wanted to use one is that i`m not sure what pump i`m using yet and i`m not spending money on a regulator, so it would just let any excess pressure back to the swril pot then the tank . and i do drive like a nutter so stopping fuel staving is a precaution :-) plus i`m making it for free :-)

Id keep the 1.0 head if your using it as a daily! The 1.3 head is simply to big for any sort of drivabitlity under 4000rpm.

Try a mix and match, use the valves off a 1.3 in a 1.0 head? Probably not ideal but seen as your giving evrything else a go

this is pretty pointless as the 1.3 head has bigger valves and ports so you dont have to mess about opening them up and the expence of getting bigger valves put in a 1ltr head . and it wont be to big as 1.3 one gets opened up for gt`s & g40`s without any problems , think of it as a big valve head for a 1 ltr

the CR ratio will also be higher in the 1.0, so more advance on the ignition = more power but you will need to run this sorta thing on higher octane fuel to stop the engine 'pinking'!

the compression will be exactly the same as the heads are flat , its the piston that will change the compression

and for the leccy ignition ,just use mk2 polo dizzy, modual and loom (its only like 4 wires or something)

Edited 4 March, 200917 yr by polo d

well, went to have a look at the saloon today, and it was better than i was expecting, only 1 downside (possibly upside?) its not a 1l, its the 1.4l

so, all the same rules apply, but slightly bigger, still aiming for 70bhp, which should be a bit easier now with the bigger engine

will probably still go with the gt cam and double coil valve springs (if they fit the stock 1.4 head)

will still be fitting the bike carbs (already bought them, so why wouldn't i )

and will still be making an exhaust manifold, but slightly larger bore, not much bigger mind, torque is still important

i do still have the option of playing with the 1l in the girlfriends bread van but as it'll be her first car, i dont want her to able to hit things quicker so it'll probably stay stock

this is pretty pointless as the 1.3 head has bigger valves and ports so you dont have to mess about opening them up and the expence of getting bigger valves put in a 1ltr head . and it wont be to big as 1.3 one gets opened up for gt`s & g40`s without any problems , think of it as a big valve head for a 1 ltr

the CR ratio will also be higher in the 1.0, so more advance on the ignition = more power but you will need to run this sorta thing on higher octane fuel to stop the engine 'pinking'!

the compression will be exactly the same as the heads are flat , its the piston that will change the compression

really, i thought the 1.3 was a 'stroker', as in same bore but different stroke to make the CC change, and this affected the CR? i thought the 1l was about 10:1 ratio and the 1.3l was about 9.5:1?

but a good way to think of a 1.3 head on a 1l is 'stage one' head... the injection pinto head is deemed 'stage one' over its carbed bredrin and is an easy way to better CFR!

This sounds very interesting.

Recently I've been thinking about getting another polo to do a project like this.

But I've got another project on at the moment that'll take a good few moths to complete.

I would go the same way as you (but for a 1300 engine):

1300 head, with double valve springs

Bike carbs (something form 600cc bike?) with homebrew manifold.

Home ported head

GT cam

MK2 polo electronic ignition style dizzy (re-curved)

And 4-2-1 DIY manifold.

Theres a lot of things you can do with the manifold to increase/shorten and move the power band around. Same with the intake manifold.

Sounds like a lot of fun.

Get pictures up.

as soon as parts start arriving/i start building i'll start up an engine build thread and stick a link to it on this thread

the guy is sticking a fresh mot and 6 months tax on the loon sometime soon, then we can swap cars (he wants something more modern and safer for his girlfriends first car, so he's having my golf as payment for the loon )

bike carbs should be here next week, then i can start on the manifold, using the engine in the girlfriends breadvan as a "template" so i dont have to strip out the loon till its ready to fit

still on the lookout for a decent GT cam and a spare head to play with, any ideas where to get them?

I'd try ebay or ask on (is there a wanted/for sale section?) here or other polo/vw forums.

been looking on ebay daily, everyone selling GT engine parts on here seems to want to sell it all together and the same goes for the 1.3 engines

may have to go raid the scrappy

really, i thought the 1.3 was a 'stroker', as in same bore but different stroke to make the CC change, and this affected the CR? i thought the 1l was about 10:1 ratio and the 1.3l was about 9.5:1?

but a good way to think of a 1.3 head on a 1l is 'stage one' head... the injection pinto head is deemed 'stage one' over its carbed bredrin and is an easy way to better CFR!

yeah they are a different stroke but both heads are flat and the blocks are the same , just the crank and rods are different the pistons come to the top of the bore in both 1.0 & 1.3`s

now so far my engine has cost me £15 and that was for a cam belt & head gasket , spec is 2g 1.3 head and block with gt crank , pistons & rods(gt bit free when i got a head for my g40) , 2g exhaust manifold (will have custom exhaust when i build it ) home made inlet and bike carbs . i need to get a gt cam but when one turns up free/cheap

been made up from bits out of the spares shed