Carb set up for 21 pund boost??

[CHUNK The Goonies]

Hi chaps current carb spec is unknown im fitting an lm 1 and wanting to know what jets I need for a starting point, ive all different sizes? Cheers! .

[Nottswoody]

I'm running 1.3 2nd stage 0.9 ac blasted down the private road at 120 and all was good 12.5 on the afrs on full throttle went to 10s then 11.5 back off the boost no higher than 13.5 I was quiet happy with that unless you guys can tell me different?

[rs250nut]

I'm running 1.3 2nd stage 0.9 ac blasted down the private road at 120 and all was good 12.5 on the afrs on full throttle went to 10s then 11.5 back off the boost no higher than 13.5 I was quiet happy with that unless you guys can tell me different?

Sounds a little rich off boost, depends if your bothered about fuel economy though, did it hold 12.5? if so maybe a little lean

[rs250nut]

Hi chaps current carb spec is unknown im fitting an lm 1 and wanting to know what jets I need for a starting point, ive all different sizes? Cheers! .

Carb type ''group a'' or standard venturi? What turbo? What boost? .............

[Nottswoody]

Sounds a little rich off boost, depends if your bothered about fuel economy though, did it hold 12.5? if so maybe a little lean

It didn't really hold anything these were the most frequent numbers i saw but full chat it was 11.5 ish

[tubbyG]

Im at 21ps on a t28, lingering about 12.1afr. Carb spec is; 1.4 second stage, 0.9 ac and 2mm needle valve. Running an efi fuel pump also.

What fuel pump you using? My phase 1 pump maxxed out about 18psi.

[Mart]

Hi chaps current carb spec is unknown im fitting an lm 1 and wanting to know what jets I need for a starting point, ive all different sizes? Cheers! .

Good starting point: Standard venturi, standard aux venturi, standard (or <) main jet, standard a/c jet, standard acc' pump jet, standard idle jet, standard (or <) 1st stage enrichment jet.

Just the 2nd stage jet & cct to 'adjust', and probably need to improve the fuel supply to the carb at that level of boost (to eliminate the float chamber from emptying).

[Ashy]

I think 18 psi is probably going to be more realistic to start with, his carb is standard in terms of the Venturi hasn't been messed with... It's running a t25 turbo....

Good point about the fuel pump, I haven't had a look but guess its a std phase 2 :crap: so that might need to be replaced....

So sounds like the std setup is the best place to start, it's been ages since I've messed with a carb, can someone confirm what the standard sizes actually are?

Is the second stage jet the one that's removable in the side or the non removable one?

Thanks.

[SCHWARTZ]

Non removable one iirc

[tubbyG]

Non removable one iirc



:agree:

[Brigsy]

Start by enlarging the 2nd stage in increments to 1.3mm. For more fuel make the air corrector smaller. You will probably need 0.9 or 1mm air corrector.

You will also need minimum of a 2mm needle jet or an adjustable fpr to ramp the pressure up with standard needle jet.

[CHUNK The Goonies]

Carb type ''group a'' or standard venturi? What turbo? What boost? .............

Standard venturi, T25, poss 18 psi :)

[CHUNK The Goonies]

Cheers for all the help chaps. Looks like ill get a uprated fuel pump, maybe a cosi one. (Mr ash I think I saw one glistening in ur parts cave) :laugh: on the RR it went leen at 5rpm , still hit 170 bhp so looking to "up" that a little bit more :laugh: safely :cooter:

[Ashy]

Mr ash I think I saw one glistening in ur parts cave

You did, its now on the raider :cooter: