carb jets

[jimmy_b]

ok my micro drill bits arrived, and i have found what i think is still a std carb.
before i remove the carb from my car i decided to have a practice with the std carb.

what i have found is

air corrector - 1.25mm (125)
main jet - 1.2mm (120)
1st stage - 1mm
2nd stage - 1mm

does this all match up to being a std carb?

[James5]

ok my micro drill bits arrived, and i have found what i think is still a std carb.
before i remove the carb from my car i decided to have a practice with the std carb.

what i have found is

air corrector - 1.25mm (125)
main jet - 1.2mm (120)
1st stage - 1mm
2nd stage - 1mm

does this all match up to being a std carb?


:agree:

[djinuk]

yuppers, u gota lm1 to check them afr's ?, might be best to post the results etc on here and get some help with what to begin drilling first, and when to stop etc :).

[jimmy_b]

i dont have a lc1 but i do have a aem wideband so i can keep a check on it.would it be worth while checkin the old jets or just start from scratch?

[djinuk]

set the boost, and see what its fueling like at the moment, out of interest what boost levels are you looking at ? if you check my previous threads you will see one where i did exactly what your doing, might offer some good advice on what order to change things and when :)..

[jimmy_b]

im plannin to run 20-25psi but that all depends if i can get the spike under control, but defo 20psi as i hope that should see 200bhp

[djinuk]

may be of interest, thsi was me fueling for 18psi

http://www.rtoc.org/boards/showthread.php?t=17611

its still a little rich , but i plan to give it another few hours of tinkering one day soon, just going to rebuild the carb first.

[James5]

Little bit of advice matey would be to set your tdc to full retard and get some det cans you don't want to do what me and Steve have just done :(

[djinuk]

out of interest james.. where do you buy them from, all the ones i see have like a 1meter cord, not longer enough to go inside the car..

[SCHWARTZ]

these seemed good for the price as opposed to a stethoscope may be a little bulky to have floating about the car all the time tho.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=180434397815&ssPageName=STRK:MEWAX:IT#ht_2001wt_905

[Markey Mark (BD)]

Little bit of advice matey would be to set your tdc to full retard and get some det cans you don't want to do what me and Steve have just done :(

Its not neccessarily full retard on the timing sensor mate, on my old engine it was only done alittle bit (about 1cm on the sensor bracket) although i have known few to have it pushed right back when using the VNT

[jimmy_b]

how do you retard the timing with the sensor?

[James5]

how do you retard the timing with the sensor?


http://www.rtoc.org/boards/showthread.php?t=4757

[jimmy_b]

ive just measured the jets of my current carb

a/c - 090 (0.9mm)
main - 130 (1.3mm)
1st stage - 100 (1mm)
2nd stage - 120 (1.2mm)

im thinking maybe change to a standard 120 main?

as soon as you touch the throttle pedal the afr's drop to 10

[James5]

ive just measured the jets of my current carb

a/c - 090 (0.9mm)
main - 130 (1.3mm)
1st stage - 100 (1mm)
2nd stage - 120 (1.2mm)

im thinking maybe change to a standard 120 main?

as soon as you touch the throttle pedal the afr's drop to 10

As you say stick a 120 main in there and see what afr's you are getting,

[jimmy_b]

jets are now

a/c - 0.9
main - 1.2
1st stage - 1.0
2nd stage - 1.2

in idle im gettin 13.6- 14.3 (guessin thats due to having a 285cam on std timing)
and the rest of the time im getting 10.0, even if you slightly touch the trottle and when cruising its just reading 10.0

it now has a hesitation also when first under load.

also i have tried to bleed off the boost abit more to hold 20psi but im not seein anymore than 17psi (20 spike) still at bottom of the carb

[SCHWARTZ]

have you adjusted it with a bleed valve? If so may be worth shortening the actuator arm a little see if that helps.

[jimmy_b]

have you adjusted it with a bleed valve? If so may be worth shortening the actuator arm a little see if that helps.

yeh its been adjusted with the bleed valve. i'll have another play with the turbo another eve and see if i can give it some more preload.

but as for the fueling i have no idea whats goin on?

[jimmy_b]

anyone?:scared:

[Woznaldo]

I'm running the same jets as you other than the 0.9 a/c (which I tried but found too rich for my 15 psi) and also have a really rich low boost area. I've just thrown in a 0.8 1st stage in but have yet to road test it. I'll give some feedback tomorrow. ;)

[jimmy_b]

could the accelerator pump have anythin to do with it? Im thinking i might need to rebuild a bog std carb and see how that reads on the afr's

[jimmy_b]

quick update, had the car running and looking down inside the carb you could see alot of fuel dripping from the venturi.
i rebuilt my carb using the body of my std carb with totally std jets through out and this seamed to solve the fuel problem at idle but ran very lean all the time.

now fitted a 130 main and .9 a/c. 1st and 2nd stage are still std 100.
idle - high 13's to mid 14's
cruise - mid 12's to low 13's
under boost (14psi) - drops to 10 initially, then when goes up to low 11's under full boost.

drives alot better but sometimes it seams to miss fire and pop under boost?

[djinuk]

maybe you could enlarge 2nd stage slightly to run slightly closer to 12 at wot ?

Im currently running the following

0.95ac
1.0 1st
1.2 2nd
1.2 main
at 18psi im getting constant 11.7 at wot on full load..

although my gentle cruising seems to be a bit rich so im going to go to 1.0 acc and see how that fairs.

[SCHWARTZ]

maybe try fitting a standard 120 main and enlarging the 2nd stage slightly.

[James5]

maybe try fitting a standard 120 main and enlarging the 2nd stage slightly.


:agree: