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Twin Webers DCOE Tuning
Posted: Tue Aug 27, 2024 1:14 pm
by Nigelsdolly
Hi all
Just bought a sprint with twin DCOE Weber Carbs on it. Problem is that the car idles at very high revs and was looking for someone or a Gge who can help. Have a few other issues as well. I am based in north London. Cheers
Re: Twin Webers DCOE Tuning
Posted: Tue Aug 27, 2024 8:57 pm
by MIG Wielder
Congratulations on your new acquisition.
Did you get any history with with vehicle ?
The reason I ask is that if it is running Webers then it may have had other mods done like a very light flywheel and a hot cam to make it more like a track-day car. And you need the very fast idle to stop it stalling at idle.
If its anything like my Lotus which runs Dellortos there is a clever idle screw which is also used to set the "suck" on the carbs;
You need an air flow meter to set up the balance.
For the Sprint the jetting should be similar to the Lotus; as both as 16V 4 cylinder arrangements.
Hope that helps initially.
Tony.
Re: Twin Webers DCOE Tuning
Posted: Wed Aug 28, 2024 9:28 pm
by B8WLY
I set mine up again only last week.
Get the airflow on each carb as similar as possible. On an air Mine are set around 5 on the meter.
Once the airflow is balanced it’s simply going through the mixture screws and getting these balanced. I normally screw mine in fully, unscrew one complete turn then adjust each one listening to how the engine sounds and responds.
This is all assuming you have the correct jets already installed in the carbs,
Hope this helps.
Richard.
Re: Twin Webers DCOE Tuning
Posted: Mon Sep 02, 2024 5:07 pm
by dursley92
B8WLY wrote: ↑Wed Aug 28, 2024 9:28 pm
I set mine up again only last week.
Get the airflow on each carb as similar as possible. On an air Mine are set around 5 on the meter.
Once the airflow is balanced it’s simply going through the mixture screws and getting these balanced. I normally screw mine in fully, unscrew one complete turn then adjust each one listening to how the engine sounds and responds.
This is all assuming you have the correct jets already installed in the carbs,
Hope this helps.
Richard.
Having just got the car it would be worth checking the jets and chokes are correct, or at least somewhere near, before trying to set the carbs up. Lots of folks just buy a set of Webers and fit them expecting miracles but they can be miles off. Are they 40s or 45s etc etc
Re: Twin Webers DCOE Tuning
Posted: Mon Sep 02, 2024 5:16 pm
by dursley92
Nigelsdolly wrote: ↑Tue Aug 27, 2024 1:14 pm
Hi all
Just bought a sprint with twin DCOE Weber Carbs on it. Problem is that the car idles at very high revs and was looking for someone or a Gge who can help. Have a few other issues as well. I am based in north London. Cheers
Be worth taking the jets out and have a look what they have fitted with. See this extract from the Triumphtune book to get a starting point.
Re: Twin Webers DCOE Tuning
Posted: Mon Sep 09, 2024 1:48 pm
by Nigelsdolly
Cheers Russ, will check it out....apologies for the late reply but was away.
Re: Twin Webers DCOE Tuning
Posted: Mon Sep 09, 2024 1:56 pm
by Nigelsdolly
MIG Wielder wrote: ↑Tue Aug 27, 2024 8:57 pm
Congratulations on your new acquisition.
Did you get any history with with vehicle ?
The reason I ask is that if it is running Webers then it may have had other mods done like a very light flywheel and a hot cam to make it more like a track-day car. And you need the very fast idle to stop it stalling at idle.
If its anything like my Lotus which runs Dellortos there is a clever idle screw which is also used to set the "suck" on the carbs;
You need an air flow meter to set up the balance.
For the Sprint the jetting should be similar to the Lotus; as both as 16V 4 cylinder arrangements.
Hope that helps initially.
Tony.
Hi Tony
cheers for the info...got lots of "work done" history and back in 2015 had a small fortune spent on it.....recently acquired for a tv show, recommissioned, tidied up a bit, and then bought by me...again for a small fortune!
The twin 40's now idle around the 1000/1100 mark...all on their own! will still set them up once i get hold of an air flow meter.
Re: Twin Webers DCOE Tuning
Posted: Wed Sep 11, 2024 12:52 pm
by shaunroche
Be worth taking the jets out and have a look what they have fitted with. See this extract from the Triumphtune book to get a starting point.
Wow, that's very useful, I'll keep that sheet for future reference!
I have both fully working 45's and 48's that have been fitted so next time I'm at the workshop I'll open them up and see what chokes etc. I have fitted.
I have 48's on the track sprint with I think the STR0091 cam fitted and that is perfectly tractable on the road.
I have the idle set to 1200 ish as when the oil is warm, the pressure can drop to about 10/15psi if idling at 750 ish...at 1200rpm it's around 30psi...