Go Back   EcoModder Forum > EcoModding > General Efficiency Discussion
Register Now
 Register Now

Reply  Post New Thread
Submit Tools LinkBack Thread Tools
Old 12-20-2017, 10:40 PM   #1 (permalink)
EcoModding Apprentice
Join Date: Jun 2010
Location: Australia
Posts: 249

Delivery 'Boy - '86 Suzuki Mighty Boy
90 day: 37.15 mpg (US)

SkipSwift - '13 Suzuki Swift GL
90 day: 35.44 mpg (US)
Thanks: 0
Thanked 52 Times in 41 Posts
Questions about modifying venturis for better... everything? (Weber DGV)

So a friend of mine is about to re-install an old (but rebuilt) 1.6 Kent motor into his MK1 Cortina. I'm not sure on the specs, but it has a 2-barrel manifold and he's looking at upgrading from the 32/36 DGV he had previously, to a 38DGMS, so he probably has more than 100hp.

The 32/36 represents the primary and secondary throttle diameter (in mm), and it has 26/27mm main venturis respectively.

I was wondering what can be done to increase airflow without changing to a different carb type, as the 38DGMS opens both throats simultaneously, so he will most likely lose drivability.

Looking at the carb, it appears that the support legs for the boosters can be streamlined somewhat, and the boosters can be knife-edged. The booster design itself is... poor. Can they be internally modified to increase flow *and* increase or maintain vacuum signal?


Originally Posted by Crazyrabbit
In God we trust. All others: bring data
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

Old 12-21-2017, 02:41 AM   #2 (permalink)
Master EcoModder
gumby79's Avatar
Join Date: Dec 2014
Location: Butte, Montana
Posts: 717

little jona - '91 Dodge D 250 first gen cummins LE
Team Streamliner
90 day: 23.4 mpg (US)

Little Jona airo modded - '91 Dodge RAM 3/4 TON D 250 24 AUTO
Team Cummins
90 day: 18.5 mpg (US)

The Salted Hound Jenny. - '87 Dodge Ram 50/D-50 5sp 4X4
90 day: 20.24 mpg (US)

Jona Allison aero - '91 Dodge Ram D-250 Le
90 day: 21.86 mpg (US)
Thanks: 207
Thanked 418 Times in 271 Posts
32/36 is what is called for on my '87 Ram D-50 2.6 for the Webber conversation , 105hp. Without supporting modds ; intske , cam , header,and exhaust the larger carbs are just toomuch carb. So I've read.
Throw a vacuum gage on it .1-3" at wide open mid to red line and the carb is the point of restriction, and bigger is warnted. 0"of vac means just right or too big. Over size is only good at top end and compromises mid and bottom rpm.
My boss from years ago had a pair 42mm's on his 69VW bug . Poor thing would pull the front tires off the ground, catching second gear. He had to delete the viscosity stacks to get the carbs to fit under the hood with only a 3"offset. When he did he had to rejet to compinsate for less/ more turbulent air entering the carb.

1st gen cummins 91.5 dodge d250 ,HX35W/12/6 QSV
ehxsost manafulld wrap, Aero Tonto
best tank: distance 649gps mi 24.04 mpg 27.011usg
Best mpg : 31.32mpg 100mi 3.193 USG 5/2/20

'83 GMC S-15 Jimmy 2door 2wd O/D auto 3.73R&P
'79 Chevy K20 4X4 350ci 400hp msd custom th400 /np205. 7.5-new 14mpg modded befor modding was a thing
87' Hyundai Excel
83 ranger w/87 2.9 L FI2wd auto 18mpg on the floor
04 Mitsubishi Gallant 2.4L auto 26mpg
06 Subaru Forrester XT(WRX PACKAGE) MT AWD Turbocharged 18 plying dirty best of 26mpg@70mph
95Chevy Blazer 4x4 auto 14-18mpg
04 Chevy Blazer 4x4 auto 16-22mpg

  Reply With Quote
Reply  Post New Thread

Thread Tools

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com