Twin 45s on standard pinto

[Mk2Neil]

Hi all,

Currently running a 205 injection Pinto engine in my mk2 Escort with a lightened flywheel and a twin choke carb, Aldon ignition and an Ashley four branch and system. I have recently bought a new twin 45 carb set up for a very good price as ive always wanted a set on the car. I know its probably overkill on a standard engine, and i would see better suited gains with a worked head and decent camshaft, but it is just my weekend toy so im not too fussed about fuel economy, just would like to experiment to see if i can use these carbs on the current set up. If i can downsize the jetting and choke sizes currently so i am in a right ball park, would this work? Enough to get me to a local dyno to have it properly dialed in. At least i would have them ready for future tuning. Would anyone be able to recommend the jet and choke sizes that would get me near?

Current carb set up is,

45 DOCE 152G

Choke 45
Idle 55 F8
Corrector F16
Mains 145


Again, i know they are large carbs on a standard lump, but hoping i can make them work somehow.


Thanks,

Neil

[Mk2Neil]

Sorry, typo! Chokes are 36mm








Neil

[Graham]

i have back to back tested 40's and 45' on the same standard injection headed engine, upto 5200rpm there was no difference but after that the 45's held on better as it went another 400 rpm before dropping off, power was only up 3bhp but the longer rev range would probably be a bonus.

so on the face of it 45's are a win, but i had to be noticeably more gentle on the dyno throttle when loading the engine up, compared to the 40's so clearly at low speed anyway they would be a bit less flexible on the road> the engine was also much more fussy about jetting, both aspects improved considerably when i swapped from 36 to 34mm chokes and power went up slightly. if i had them i would of tried 32 or 33 chokes.

what your calling a corrector is the emulsion tube, the air corrector is in the top of the tube, you expose it when you pull the jet holder off the top of the tube.

ignoring the missing jet info 36 chokes and 145 mains will work, but i strongly suggest swapping to 34 chokes, on the dyno i used 135 main 155 air i found 55F9 idles too lean and used 55F6 with both choke sizes

[Mk2Neil]

Thank you Graham,

You have made my day as I was thinking that it was not feasible. Will order some 34mm chokes, 135 mains and 155 air jets plus some 55F6 idle jets. I'd better get a fuel regulator as well now too!


Neil

[Graham]

Thank you Graham,

You have made my day as I was thinking that it was not feasible. Will order some 34mm chokes, 135 mains and 155 air jets plus some 55F6 idle jets. I'd better get a fuel regulator as well now too!


Neil

on the 32/36 the engine had 107bhp i finished up with 120bhp on 45's so a good gain, upto 4000 rpm you wont gain anything over the 32/36

[Mk2Neil]

That's not bad, I take it that was with a standard cam?

[Graham]

That's not bad, I take it that was with a standard cam?

yes, engine was totally standard pinto fitted with an unmodified injection head, in the future i will re run the tests with an upgraded cam

[Forest_rallying]

yes, engine was totally standard pinto fitted with an unmodified injection head, in the future i will re run the tests with an upgraded cam

I hope you aren't giving away too much of your Media information too soon Graham.

I once knew of a Man in the early eighties that slapped a set of 45's off his Road Rally car onto his then Girl friends std RS 2000 and when and won the Rally. I can't imagine he even bothered with the jetting.

[Graham]

I once knew of a Man in the early eighties that slapped a set of 45's off his Road Rally car onto his then Girl friends std RS 2000 and when and won the Rally. I can't imagine he even bothered with the jetting.

the 45's were brand new out the box with weber supplied jetting, 145 main 36 chokes, they actually worked ok, all be it with a LOT of fuel standoff, some of that was probably me loading the engine up at only 2000 rpm, but you could of certainly used them like that. but it was so so much nicer with 34 chokes, and thats on the dyno, on the road it would of been chalk and cheese. im sure i could of gone smaller on the chokes without loss of power

[Forest_rallying]

the 45's were brand new out the box with weber supplied jetting, 145 main 36 chokes, they actually worked ok, all be it with a LOT of fuel standoff, some of that was probably me loading the engine up at only 2000 rpm, but you could of certainly used them like that. but it was so so much nicer with 34 chokes, and thats on the dyno, on the road it would of been chalk and cheese. im sure i could of gone smaller on the chokes without loss of power

It's very similar to what I have now on my Car, GTS 4 cam with all the trimmings but still retaining 36 mm ckokes on the Weber 45's. The Car's all finished but still not yet been out on the Road. How times have changed, 40 years ago I would have been straight out in it regardless of Road Traffic Laws regarding MOT's and Tax.

[Graham]

. How times have changed, 40 years ago I would have been straight out in it regardless of Road Traffic Laws regarding MOT's and Tax.

it was a different world back then, in my younger days it was rare we had mot, tax or insurance, to have all three was highly unusual, i did once get prosecuted for No mot, the fine was about the same as the mot test itself, and way less than getting it to actually pass the test would of been. Between my mates we probably clocked up a million motoring offenses a year, almost all of which we got away with, but always moaned about the old bill pulling us over! but it was a fair cop!

[Mk2Neil]

34 chokes and jets all ordered, plus filter regulator, throttle cable etc.Quite excited now! As long as I can get a syncrometer in there on the trumpets to sync both carbs, we should be good to go I recon before a dyno.

[Graham]

34 chokes and jets all ordered, plus filter regulator, throttle cable etc.Quite excited now! As long as I can get a syncrometer in there on the trumpets to sync both carbs, we should be good to go I recon before a dyno.

i have a syncrometer but 90% of the time balance them by ear using a 1/2 bore length of heater hose

[Mk2Neil]

Good call! Thank you Graham 😊

[Mk2Neil]

Just another question, I'm running a manual fuel pump so would I still need a regulator to get the pressure around 3psi or can I plumb the pump straight to the carbs?

[Graham]

Just another question, I'm running a manual fuel pump so would I still need a regulator to get the pressure around 3psi or can I plumb the pump straight to the carbs?

it will probably be ok without

[wildo105e]

Just another question, I'm running a manual fuel pump so would I still need a regulator to get the pressure around 3psi or can I plumb the pump straight to the carbs?

Lotus twin cams ran a manual pump no regulator.


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[Mk2Neil]

Thankyou Gents

[Graham]

back in the 80's a regulator was a must have thing on everything, but if your needle (float) valves are in good shape there really isnt any need for one on a manual pump