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Dhla 40 Jets For A 1300


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i emailed a bloke asking about what jets i should use for my 40's which are soon to be going on my mk2 golf 1300, he reccomended as a starting point;

chokes 30

mains 115

airs 200

em.tube f11

idles 45f8

pump 35

n/valve 150

do you think these sound more or less right? I'm going to get it RR'd but i dont want them to tell me I've done it all wrong and have to buy another set of jets etc.

my golf is fairly standard bar a full powerflow system and i will be adding a GT cam.

thanks in advance, konrad.

Edited by konradmk2
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twin40racer

It will run fine on them, but maybe a little rich i'd have thought.

I used 29mm chokes on a 1400 and got 95bhp, so 30's are probably oversized. you could use 28's or 26's and then jet it from there. - 28's probably best.

A general rule that i've read is to get the choke size and multiply by 4 for the main jet size, so 28mm chokes with 110's would run fine. Then air corrector size of 200 sounds ok. 33pumps would be fine. 7772.5 tubes would be fine and needle valve 150's fine. Then the RR tune for the best power.

Edited by twin40racer
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what carbs are they?? if they have a letter after DHLA40 then you will find that you cannot fit 7850.n idle holders and are restricted to 7772.8,.10,.11 emulsion tubes. the idles will have to be increased to 58s or 60s.

if thats the case then you want to get a set of 7772.8 emulsions as they're the earliest starters and hold the strongest mix.

keep the airs and the mains

you've been quoted weber numbers

45 idle 7850.1 idle holders

reduce the size of the air corrector to about 170

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what carbs are they?? if they have a letter after DHLA40 then you will find that you cannot fit 7850.n idle holders and are restricted to 7772.8,.10,.11 emulsion tubes. the idles will have to be increased to 58s or 60s.

if thats the case then you want to get a set of 7772.8 emulsions as they're the earliest starters and hold the strongest mix.

keep the airs and the mains

you've been quoted weber numbers

45 idle 7850.1 idle holders

reduce the size of the air corrector to about 170

they have a 'H' after the dhla40.

thanks.

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  • 7 years later...

Found this 1971 spec for twin cam 1290cc Alfa Romeo Giulia Super 1.3 which I think is 100+ BHP 9:1 compression ratio

1971

http://www.carfolio.com/specifications/models/car/?car=100034

1972

http://www.carfolio.com/specifications/models/car/?car=37125

 

Chokes 28mm

Main 110

Emulsion .5

Air corrector 200

Idle 48/7850.1

Pump 33   (4cc per barrel per 20 strokes)

Aux venturi .1

Starter 70/7840.1

alfa1300dhlajets.jpg

 

Edited by dvderlm
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In contrast the single cam 1298cc 87bhp Vauxhall Nova Sport 1.3 in road trim used Weber DCOE (143&144 matched pair)  - compression ratio 9.2:1.

Choke 28 mm

Main jet 100
Emulsion tube F47

Air corrector 160
Pump 40
Idle jet 59f21 (4x1.10 mm bleed)
 

Edited by dvderlm
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Lancia Fulvia 1.3 coupe (sport and zagato)

http://www.viva-lancia.com/fulvia/qanda/carbs/dellorto.php

 

Used similar smaller than DHLA40 twin carbs Called DHLB35. some parts interchangeable, but sizes interesting as this was an upgrade on Solex C32 PHH twins rated 87bhp.

 

Chokes 31mm

Main 112

Emulsion 7772.4

Air corrector 200

Idle 45/ and 1 x  1.2mm air

Pump 45   (2.5 +-0.5cc  per barrel per 20 strokes)

Aux venturi 8178.1

Starter 70/7482.2

Edited by dvderlm
7772.04 dellorto was almost a googlewhack
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Renault Alpine A110 1300S (R8 Gordini type 804)

(120 BHP  compression ratio 12:1)

Weber 40DCOE (29&30)

 

Chokes 33mm

Main 130

Emulsion F15

Air corrector 200

Idle 50f8

Pump 35 

Edited by dvderlm
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Lancia Fulvia 1.3 HFR Variante 1014 (122 BHP @ 7200rpm?, 9:1 compression ratio)
(according to Solex S.p.A. Technical Bulletin No. 71/October 1967, supplied by the Lancia Competition Department)
http://var1016.blogspot.co.uk/2006/12/fulvia-thoughts-6.html claims 132bhp, but most sources say that's 1.6HF power) 
 
Solex C. 40 DDHF
 
Choke 34
Main Jet 145
Air Corr Jet 155
Idle jet 50
Edited by dvderlm
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  • 2 months later...

If you speak French there's a mec called Jean-Christophe Nieutin who has done tuning on Lotus7 1600 and Alpine A110-1300. He likes Webers, so much so that he's created an Excel spreadsheet for calculating optimal jet sizing

(and loads of other info...).

http://a110a.free.fr/SPIP172/IMG/xls/Carburateurs_Weber_NIEUTIN.xls

 

It works with LibreOffice.

 I edited for my GK which I think prefers lean as 11:1 compression.

I adjusted the fuel coefficient (cell C1) down to 94% 

It's ONLY 1263cc (cell B6) according to the Farhzeugbrief, I think because the piston bowl is smaller. 

I set the bore to 75.0mm (D6)and it worked out the stroke as 71.5mm.

I chose Souplesse=flexibility over Performance/"puissance" (cell B8).

I guessed the idle jet has 4x1.10mm air holes (B2 and B2) and it reckons a single 2.2mm air hole is as good.

I aimed for max power at 5500rpm.

 

and it suggests

 

idle 40F8

chokes 26mm

main 100

air corrector 160

pump jet 30 to 35

emulsion F11 rich or one of F16, F15 and F9 to weaker.

 

jc nieutin weber 40.PNG

 

If you have other choke sizes either side of 26, there are suggestions for these in row 8 and 9.

It chose the 100 from a list of available sizes for Weber rounding up from size 98 (cell B11)

Dellorto do a 98 jet!

 

It also works out the engine is Super Carré, which I think means over square so can manage 8811 rpm max, before piston speed exceeds 21 metre/second !

 

 

Edited by dvderlm
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  • 1 month later...
  • 2 weeks later...
dvderlm

Citroen Visa Rally 1285cc

http://www.citroracing-historique.org/Documents/WeberSettingsVisa.pdf

 

Weber 40DCOE 185

 

35 choke

140 mains

165 airs

F47 emulsions

59f21idles

35 pumps

4.5 aux venturi

 

Float lowered 1mm to 8.5mm from std 7.5mm.

ignition

Fixed advance 32° at 5000 rpm.

Others have 4.6° at 1000rpm and 30° at 5000rpm 

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  • 1 month later...
dvderlm

Sideways Forum

http://sideways-technologies.co.uk/forums/index.php/topic/5892-what-carburettor-race-1300-engine/page-3#entry78256

 

contributor DaveNotSoSideways (who I suspect is "Barry Scott crazy spitfire" blogger David Powell http://crazyspitfire.blogspot.co.uk/2006/06/days-like-these-make-it-all-worth.html)

 

suggests turning down a .7 emulsion tube in a lathe as .5 tube is too thin.

 

34mm choke

.1 venturi

33-40 pump

125-135 main

lathed custom .7 tube

150-160 corrector

idle 55 in 7850.1 holder.

 

Or to use a .6 emulsion tube:

 

34mm choke,

.1 venturi

35-40 pump

128-135 main

6 tube

120-140 corrector

idle 55 in 7850.1 holder.
 

But I also found why he likes large idle - his engine is run very cool

http://crazyspitfire.blogspot.co.uk/2005/01/weber-dcoe-dcom-jetting.html

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  • 1 month later...
  • 4 weeks later...
dvderlm

Talbot Samba Rally (90hp @6700rpm -not the 135bhp group-b )

 1219cc

 

33 chokes

130 main +-5

195 air +-5

F47 emulsion

55f21 idle +-10

with 110f2 air-bleeds

40 pump jet +-10

rallysamba.PNG.600dc751a568fb78e778924b6bd2af6f.PNG

 

 

 

Edited by dvderlm
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  • 2 weeks later...

Alfa GTA 1300 "Elaborazine Facetti"  (1972 race car)

95bhp @ 6000rpm 10.5:1

(or 178hp @ 9,300rpm with 11:1cr)

 

1290cc 78x67.5 bore x stroke

 

DHLA45!

40 choke

.1 venturi

165 main

.6 emulsion

170 air

50 idle

.1 idle holder

33 pump

volume 7.5cc +- 0.5/20 strokes (per barrel)

Edited by dvderlm
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  • 3 weeks later...

Simca 1000 Rallye 3 (1294cc)

103hp 13:1 CR

 

Weber DCOE 40 120/121

32 choke

6 aux

160 main

F41 emulsion

190 air

40f8 idle

40 pump

float lowered 7.75 and 8.25mm (front and rear carbs?)

Edited by dvderlm
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  • 4 months later...
On ‎04‎/‎11‎/‎2016 at 22:28, dvderlm said:

DHLB35 ... as this was an upgrade on Solex C32 PHH twins rated 87bhp.

which were jetted:

26 choke

107.5 main

180 air corrector

47.5 idle

40 pump

7cc per cylinder from per 20 strokes?solexc32phh.PNG.1f622df9465b6c86599e95465d4836b4.PNG

 

Edited by dvderlm
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  • 4 months later...
  • 1 month later...
dvderlm

http://la205rallye.free.fr/doc/noticecitroensportax.pdf

Citroen AX Sport 1.3

1294cc 94hp

9.2:1 CR

 

Weber DCOM 40

32 choke

115 +-5 maim

140 +-20 air corrector

F68 emulsion (very holey, hence small air corrector) 

58f21 idle (+-5)

35 pump +-5

(40/f9/130 starter circuit? or alternative idle stsck?)

float level 14mm (plastic) 7mm (brass)

 

or

 

Solex ADDHE 40 

32 choke

130 main

210 +-20 air corrector

A05 emulsion

55 idle +-5

50 pump jet +-5

1 to 2mm pump travel

( 140 starter fixed)

float level 43mm

 

I guess different temperature, altitudes, rally track surface are the reason for the +or-- values. But either carb types are suitable for exact same engine..  

Edited by dvderlm
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  • 1 month later...

Ford Capri/kitcar 1300 crossflow

https://fastroadcars.co.uk/store/index.php?route=product/product&manufacturer_id=11&product_id=390

 

Weber 40 DCOE 151

  • Choke 30mm,
  • Aux.venturi 4.5
  • Main 115
  • Air corrector 200 
  • Idle 45F9
  • Pump 40 Back bleed 50 
  • Emulsion tube F11
  • Needle Valve 175

39mm long trumpets

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Yes.

But where else would I create the best collection of twin carb 1300 data on the web?

 

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  • 4 months later...

Skoda S120 (Rallye ?) 

1300cc 111hp @7250 rpm

10.8:1 CR

DCOE 2

 

34 choke

145 main

180 air corrector

45 idle

80 pump? enrichment power jet??

 

with 320 degree duration cam.

 

This one is using DCOE45s and a Felicia engine

 

 

 

Edited by dvderlm
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