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g27builder · New user Joined: 05 May 2008 Posts: 3

Hi all,

I have a Ginetta G27 with a 2 litre Pinto and twin 45 DCOE's. I am having a problem with the mid range, the car idles fine and above 3,000 rpm it pulls like a train but cruising in traffic it's as lumpy as hell, spitting back through the carbs and the car almost stalls when accelerating from anywhere less than 3,000 rpm.

The 45 DCOE's appear to be a matched pair judging by the numbers stamped on the bodies and have the following jets etc.:

36 mm chokes
150 main jets
170 air correctors
F16 emulsion tubes
50f8 Idle jets
50 pump jets
100 Pump bleed
Pump stroke 14 mm
225 Needle valve

I have balanced the carbs with a synchrometer and the static timing is set at 12 deg BTDC at an ide speed of 950 rpm. I have tried timing anywhere between 4 and 20 deg BTDC without any significant change in performance.

Any observations of the above setup or advice in general on setting these up would be much appreciated as I'd hate to have to go back to my single downdraught carb as the air filter doesn't fit beneath the bonnet.

g27builder · New user Joined: 05 May 2008 Posts: 3

I assume from the large number of views but lack of responses that the jetting looks OK. So here's another question.

Would excessive fuel pressure and low fuel volume cause this type of problem. I have a Facet electric fuel pump that I think delivers around 4.5 psi pressure but it's only the small pump and the volume may be quite low. I would have thought that this would be more of an issue at full throttle but could this be the source of my mid range problem?

I could temporarily go back to the mechanical fuel pump which will deliver nowhere near enough fuel for full throttle but may test out any theory that fuel pressure is an issue up to 3,000 rpm

admin · Site Admin Joined: 03 May 2007 Posts: 19

Hello. I did manage to find a calibration that has apparently been successfully used for 45DCE on a 2.0 Pinto. This is

38mm Chokes
F11 E Tubes
150 main jets
45F9 idles
185 Air correctors
40 pump jets

I wouldn't have thought the chokes would be the problem so maybe try idles and air correctors first , then change the E Tubes. You also may want to check the needle valves and float height.

g27builder · New user Joined: 05 May 2008 Posts: 3

Thanks for that. I have spare 45f9 idle jets and f11 emulsion tubes so I'll give them a go. I'll also order some 185 air correctors.

In my spec I've given above I quote pump bleeds of 100. I've been told 50's would improve things but dont really know what these are or what they're officially called as I cant see them listed as spares.

admin · Site Admin Joined: 03 May 2007 Posts: 19

Hello. Our understanding is that the pump bleeds supplied in the standard 45 DCOE (40) work fine, so the 100s are likely to be too large and you should probably drop to 50 as recommended.

bigjim5551212 · Posted: Tue Jun 03, 2008 5:15 am Post subject:

your fuel pressure is too high. No more than 3.5 psi.
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