Right so I've read through nearly every bike carb thread i can find, and i know this is getting tedious now

but MikeyMKs AEE keeps popping up with vacuum hose and top hat flanges attached to the block using o rings?

has anyone or Mikey done this and has a picture of it off the car, as i have no clue how this method would be created especially the top hat flange bit?

and haven't really got money for boggbros to make me one

sorry if this has been explained, i just cant find it

no matter how much i look

thankksss

Edited 2 June, 200917 yr by Gageyo

the ports arent circlular and taking additional metal out of the head is not ideal, the last thing you want in a step in the intake. best option is a plate cut to the dimensions of an intake gasket and tubing squashed and crimped to the shape of the port, no steps, just a smooth transition between the circular bike carb and the squared off ports.

You could use weld or filler/liquid metal in a round pipe to get the correct shape.

Not as good, but maybe cheaper and easier for the home DIY-er.

http://www.clubpolo.co.uk/forum/index.php?...mp;hl=flowbench

http://www.clubpolo.co.uk/forum/index.php?...25&start=25

Edited 1 June, 200917 yr by varnish

the flange method seems easier to achieve,

but MikeyMK produced his own flanges on a lathe, which i dont have access to

any idea where I could get some?

Even the Bogg Bro's manifold leaves a huge step,but the flow drops off of it instead of flowing into it.

The drop-steps are very small on mine in comparison,as seen in the drawing above.

Also shown in the drawing is the way the tubing is stretched over the carbs and flanges,which helps keep the internal shape good for flow. This was achievable because the tubing i used is spira-wire reinforced instead of braided (correct for vacuum,as braided is for internal pressure) and i heated the tubing before twisting it on.

The carb and flange are both about 44mm around the outside,and the internal diameter of the tubing i used is 40mm.

Braided hose,only for use on tubular manifolds,probably wont stretch that far so it'll need an ID of 43-45mm. But if using a manifold,id use the standard bike ones instead.

I didnt get a good pic of the flanges i used this time,although there's a great pic of the brass ones i made for my 1.4 8v somewhere in this forum,posted possibly sometime last spring.

I'll try to find it,but its locked in photobucket which i cant use with this phone.

Here's the only shot i got of my current ones..

Edited 25 August, 200917 yr by MikeyMK

I don't think it's necessary to use a lathe.

Mikey what did you use the lathe for?

I think you could make something similar with a mig welder and a black and decker with a few drill bits and couple of grinding stones.

i have access to a mig welder

so basically, make up a plate with circular steel rods attached, that match up to the ports, by removing some of the metal from the head so that it is also circular?

then attach that beefy piping so none of the bending and crimping of steel tubing is needed?

Or weld pipes to a flange plate made from an inlet gasket as a template, then attach the carbs to the pipes.

Just make sure the angles for the pipes are so the carbs can attach cleanly.

with welding the pipes though will i still have to remove some metal from the head?

therefore not being able to return the car to standard, using original inlet due to the change in bore?

You could add meterial to the pipe and port match that way.

Or use thicker walled tube and port match the round tube.

but that way would each pipe not have to be exactly identical?

never ported anyhting and could provide a problem

Loving how this forum has suddenly come alive with technical knowledge in the last few days!

sarcasm much?

NO, it actually wasnt, its nice to have some informative reading instead of the usual pants threads asking the same questions over and over (you know the sort)

So actually it was more of a thankyou :-)

I've done my manifold using top hat flanges made from block of aluminium on a lathe. Could be done without a lathe but I had access to one so was the easiest option.

Luckily for me, the ports on a mk4 head are round, so did not have any of the above problems.

but that way would each pipe not have to be exactly identical?

never ported anything and could provide a problem

More of a problem than cutting large amounts out of the cylinder head?

The pipes wouldn't have to be identical to each other. Just matched to the inlet port face on the cylinder head.

I've done my manifold using top hat flanges made from block of aluminium on a lathe. Could be done without a lathe but I had access to one so was the easiest option.

X2.

I'm sure there are various other ways,but this is just the way i figured to do it,based on the materials and tools i had access to.

My ports were round on the first engine,though (AEE).

As for porting the head,it'll still take a standard manifold,its not like I've written the head off - but i have written the standard manifold and induction off. Why would i ever use it when its inferior in every way?

i take back my comment about the non round ports, on an AEE

all of the 1.05, 1.3 and 1.4 heads i have seen are 0 shape

Edited 1 June, 200917 yr by polopete

as for the different methods of making the manifold, they all seem to be pretty succesful on a low budget

I want to have a go at this myself

would this method work,

make a base plate to fit the head, using an inlet manifold as a template so the ports match up

mig weld four cylindrical sections of steel to the base around the ports, these wont be too long say around 2cm

then metal filler the tubes from the top of the cylinder, down to the ports so that it creates a smooth flow with no great steps

then stretch some hose (mikeyMK stylee) around these flanges to then fit to the bike carbs

i figured that this would eliminate the need to massacre the head and would also not be too difficult to manufacture

if anyone can see any faults with this then please let me know

btw i think I'm going to run cbr600 carbs on my mk3 gt as they seem to be quite popular

again i know this has been asked a million times but there doesnt seem to be a definitive answer

R6 carbs or CBR600? or does it not really matter as I've seen both used and wondered what the advantages and disadvantages of each are

Edited 2 June, 200917 yr by Gageyo

I would use a gasket as a template. Not the manifold.

I think the runners will have to be longer than 2cm. Like five to ten times that length.

The longer the runners are the better the low down torque will be (I think. I may have that backwards).

Also 2cm is a bit mean when trying to hang a (relatively) heavy of of carbs. Esepcially when supporting them with only a jubilee clip and some hose pipe.

Also, the carb spacing will not be the same as the port spacing, so you'll have to take that into account. 2cm may not be enough to take up the difference.

See photo:

The runners are not straight, but angled to meet the carbs.

I'd make the runners as long as would easily fit in the engine bay, and use the head as a jig to weld the pipes into place.

yeah sorry meant gasket and not manifold

and as for the runners, the proposed 2cm would only be flanges to attach the industrial hose to, so the hose would be the same length as those shown in the picture above but would also eliminate the need to remove metal from the head as the flanges moulded to shape using metal filler would match the ports of the head

I would also not have to weld the pipes at angles as the industrial hose would bend and create a curve to match up with the bottom of the carbs

also are the ports on the GT head the same as the 1.3 head?

as I've got a 1.3 head spare that i could mockup on as I use the GT as a daily and dont wanna take it off the road if i can help it

My worry would be the hose not being strong enough to hold the carbs over that kind of length. Esepcially when heated up in a hot engine bay.

But I suppose if its the reinforced stuff it might be okay, but I would use as short as piece of hose as possible. Literally almost butting the manifold runner and carb together, with the hose only there to make an air tight join.

I think difference between the 1.3 head and the GT head is just valve train stuff i.e cam and valve springs.