I don't know about poloshow actually, apparantaly I should?

try a bigger idle jet, the carbs using only that jet until 1/3 throttle

from 1/3 to 2/3 the needle coms in play along with the main jet

from 2/3 to full trottle it s only the main jet

Bigger pilot jet would make it even richer?

sorry smaller

Haha, thought that's what you meant :p

My pilot jets are an emulsion tube too? Surely there's massive variations?

Got 40's in at the minute I think, only others I have are 42's

i think i run 45 , don't know for sure

i dont have to look at emission norms mine polo is to old for that

Edited 14 April, 201214 yr by sander_beer

so you have 45 pilots, 135 mains, air screws fully in...what about needles? Also, how you running such small mains? Do you have a small amount of holes in emulsion tubes or blocked off secondary air jets?

Haha.

Btw yoof. I'm gonna beat you at the track day thingy, even at pod if you like, you know naffinnnnnn.

I love a reaction

Your coming Poloshow aint you? i'll give u an irection As I'm sure will mr chicken holder.

ahh yeeee!

so you have 45 pilots, 135 mains, air screws fully in...what about needles? Also, how you running such small mains? Do you have a small amount of holes in emulsion tubes or blocked off secondary air jets?

45 pilots 135 main blocked airjets stock needles air screws +- 3 turns out

I have 40 pilots, 125 mains, blocked air jets, air screws 1.5-2 turns out, standard needles with no shims & is still a bit rich haha.

As you have 900cc carbs, do your needles have like a thin section on the pointed end, about 10mm long?

Also just out of interest, do you know what your cam is timed up to?

I very very much doubt you'll get it through a cat test on the carbs unless you run it very lean. I still stand by my comment earlier in the thread, it really would just be easier (and kinder to your engine!) to have a friendly MOT.

If you really want to keep it above board then I really see no option other than to fit the original EFI!

I think realistically it boils down to two options,

1. Dodgy MOT

2. Put the EFI and CAT back on for the test, as Yoof suggests.

Otherwise you're going to spend a ridiculous amount of time tweaking and hoping mate. Not too bad if you've the ability to read all tested emissions, but with only a wideband AFM you could never guarantee that all your hard work was for nothing.

Oh yeah tbh I dont think youd get it to pass one anyway, unless you spent a lot of time optimising ignition timing and such to suit emissions, theres no adaptation for loading like with EFI.

just generally got interested in other peoples setup really haha :)

tbh PPM & lambda arn't too bad, the HC is whats high.

lambda needs to be 0.97-1.03 at fast idle (2500-3000) HC below 200 and ppm below 0.200% i think

natural idle is 450-1500rpm and HC below 200, i think, maybe muddled up.

but anyway, carbs dont seem to hold as steady an AFR as injection so would be a game just to keep it within the tolerance (around 14.26 - 15.1 :1 AFR)

I thought you passed the MOT last friday? what were the emmisions like on the printout?

i cant remember what i did this morning haha, dunno where print out is, it wasnt tooo bad

Last MOT.

This was just after changing the stem seals as i had a slight blue smoke issue and was still burning off the deposits.

CO = 2.32 (Limit 3.50)

HC = 1188 (Limit 1200)

This was a cold engine with shit fuel and quickly timed up after doing the head seals.

Your Limit is 1200 on HC. Mine is 200. Lool.

Ye. lol.

Ill get the emission details for the mk2 on weber 32TL that had its MOT test today up when i get them.

It failed on back brakes being ineffective.

Oh yeah tbh I dont think youd get it to pass one anyway, unless you spent a lot of time optimising ignition timing and such to suit emissions, theres no adaptation for loading like with EFI.

just generally got interested in other peoples setup really haha :)

tbh PPM & lambda arn't too bad, the HC is whats high.

lambda needs to be 0.97-1.03 at fast idle (2500-3000) HC below 200 and ppm below 0.200% i think

natural idle is 450-1500rpm and HC below 200, i think, maybe muddled up.

but anyway, carbs dont seem to hold as steady an AFR as injection so would be a game just to keep it within the tolerance (around 14.26 - 15.1 :1 AFR)

Excessive levels of hydrocarbons in the exhaust emissions is indicative of an incomplete burn. So in your cylinder(s) (it might not be all of them) the mixture isn't burning effectively, and this could be down to over-rich mixture, poor sparking leading to misfires or low compressions/leaky valves.

Have you changed the plugs from standard specification? There's no real need and I doubt you need anything colder than a BP6ES (NGK). Are the plugs coming out black or discoloured in anyway?

You say you have changed the camshaft, is the overlap too great? Excessive overlap will reduce compression and allow burnt/waste gases to remain or be drawn back into the cylinder at low RPMs.

Ignition timing you say is set about 16 deg. static? I would say a typical figure for a 'clean' burn would be more like 18-24, but it depends. The ignition is advanced to allow more air to be added to the mixture as it burns slower than fuel, hence requiring an earlier spark. You say you've had the distributor re-curved, but without the car/engine? I can't say thats possible, well it is but I doubt the re-curved is anything near suitable for the engine you are trying to build....

Erm 268/268 cam.

I'm running iridium plugs. They seem to give a cleaner burn than standards, I tried a colder plug due to higher comp but was too cold to still on 6's.

Yeah I was confused about how on earth they can reprofile a dizzy but yeah, beyond me.

Better than a 1.3 8v dizzy running a totally different cam and such.

The Dyno time for modding the dizzy right would probably be equal costs to fitting mappable ignition anyway haha.

Anything this threads irrelevant now :)

I had pics of plugs somewhere, they're fairly clean tbh. Just a struggle to get the AFR right with no load. Therefor it's rich and without a lot of advanced it probably wouldn't reduce the HC enough.

IMO the emissions test is utter shit anyway