Corvair DiagramCorvair Photo
Corvair Center
home forum corvairs calendar links Corvair Podcast
California Corvairs
Clarks Corvair
Clarks Corvair
“Performance
“CORSA"



Chevy Corvair License Plate
Chevy Corvair Chrome Wheel
Corvair Center Forum :  Corvair Center Phorum The fastest message board... ever.
Corvair Center 
Weber 45 DCOE Turbo Tuning
Posted by: JimBrandberg ()
Date: August 05, 2017 12:02PM

I have a Weber with vacuum progressive I'm installing. It has 4.5 auxiliary venturis, not sure what that translates to in millimeters. It's got Inlet tube drilled from 2 to 275, 180 Main Jets, F16 Emulsion Tubes and 65 F8 Idle Jets.
It will only idle with 3 + turns out on the mixture screws which would call for richer idle jets. My supplier Pegasus shows 65 being the richest F8 jet with F9 being the next step, starting a new progression at 50. Normally a Corvair starts with a F8 55 so I'm already 2 steps richer than usual.
With it wanting all this richness, I considered a vacuum leak but spraying brake cleaner around the gaskets surfaces did not change the engine speed. It didn't come with base gaskets so we made some from gasket paper, I'm planning to order a pair along with some idle jets.
It was running good with the Carter YH so I'm certainly not going to fiddle with anything els at this time.
I did Search but didn't find much.
Anyone have some Weber wisdom and recommendations? Thanks,
Jim Brandberg
Isanti, MN
CorvairRepair.com

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: Leon ()
Date: August 05, 2017 12:15PM

I've been having to rejet a ton of Weber carbs lately with larger than normal jets just to get them to idle due to ethanol, might not have anything to do with yours as I don't know the composition of your fuel.

Last one was a XKE V12 with six 45 DCOE carburetors, that was fun hot smiley

Star NC
1965 Monza Coupe, turbocharged 140/4spd, Carter AFB 4bbl, E-flow Crown turbo, water/meth injection, driver
1965 Corsa Coupe, 140/4spd, future project
1966 Monza Coupe, 110/4spd parts car
1966 Monza 'vert, 95/PG parts car
1985 Dodge W350 4dr turbocharged 440/4spd



Edited 1 time(s). Last edit at 08/05/2017 12:21PM by Leon.

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: JimBrandberg ()
Date: August 05, 2017 12:38PM

V12 is certainly sexier but you can't beat a Jaguar big 6. I heard mounting Lucas coils in the heat of the V 12 valley isn't so good either. In my opinion the XKE is one of the loveliest cars ever made. It was funny on "Mad Men" when the guy tried committing suicide with one and it wouldn't start. But I digress... Hate to run my own thread and idle jet inquiry off the rails.
Jim Brandberg
Isanti, MN
CorvairRepair.com

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: 63turbo ()
Date: August 05, 2017 01:43PM

Jim- I think you are going to want to go to F9's on the idle jets... some
do well with 50f9's others need 55f9's. I was never very happy with any of the
f8 combinations that I tried- 50f8, 55f8, and 60f8. For my engine, 50f9's worked pretty darned well- I seem to recall the mixture screws were out around
1 3/8 with those jets in. Weber's on turbo Corvairs seem to like more timing at idle, and a higher idle... be happy with a 1000- 1250 idle. Forget trying to run the stock 850rpm idle!

The other thing- what are the choke sizes again? I found that the weber rules
worked pretty well for main jet sizing- in other words, if you have a 32mm choke, then the main needed to be 4xthe choke size, so 4x32= 128., and then the air corrector needed to be 30 to 40 bigger than the main number... so
for example, if the main was 128, then the air corrector= 40+128= 168.
You can and should stagger your main jet sizing if you are running a smaller
primary choke than secondary. For a very long time, I ran a 32mm primary, and
a 34 or 36... depending on how much peak boost I was after. The secondary main jet sizing ended up being a bit richer than the rules.

I got MUCH better throttle response with a 29mm primary, and ran that for a long time also... but it did cause the light load cruising to be stupidly rich,
no matter how lean the jetting. I think once I found that out was about the time I started wanting to go to EFI...

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
engine less 62 Spyder
Canadian 64 Monza Parts car






Edited 1 time(s). Last edit at 08/05/2017 01:50PM by 63turbo.

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: JimBrandberg ()
Date: August 06, 2017 06:19AM

Thanks for the replies, both here and private. I've printed them off and certainly would be happy for more.
Jim Brandberg
Isanti, MN
CorvairRepair.com

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: JimBrandberg ()
Date: August 07, 2017 06:17AM

I can't get it to idle at less than 3 turns out on the mixture screws.
Started with F8 65 idle jets which was #70 drill bit. Opened up to 69 then 68 with no change. Changed to F9 60 idle jets, still the same.
It's a progressive vacuum secondary conversion but I haven't moved past the idle problem yet. The owner got it off Ebay and sent it in for conversion and doesn't know the history of it.
There's a pressure regulator, I went from 4 #s to 3 to 2 with no change in the idling characteristics.
Part of the conversion has the idle stop screw on the secondary side. I'm trying to get an idle at 1/2 turn down to stay out of the transition circuits as per the instructions. The idle speed is responsive to the stop screw located on the secondary side.
When I say no change I mean it won't keep running at less than 3 turns out on the mixture screws. You can smell the richness in the exhaust.
The idle doesn't change with brake cleaner sprayed around the gasket surfaces. It ran fine with the Carter YH so I'm reluctant to mess with the rubber hose or gaskets to the head at this time.
Jim Brandberg
Isanti, MN
CorvairRepair.com

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: 63turbo ()
Date: August 07, 2017 07:47AM

Be clear on this: both throttle plates MUST be set with the back edge just
visible on the first progression hole!! The back edge of the throttle plate
is the side of the plate facing the air cleaner... you may have to do some
tweaking to get the butterflies exactly parallel to one another so that both
are set just visible at the front edge of the first progression hole... but
whatever, that is how those butterflies need to be set for a good idle... it will cause a higher idle speed (1000-1250) but that is how that carb has to
be set to idle right!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: Melb-Mike ()
Date: August 07, 2017 08:48AM

At the risk of telling you something you already know, Bob Helt's book, The Classic Corvair 10th edition, has a section on Webers and recommendations for jetting. Forgive me If this is redundant, I know absolutely nothing about Webers. Good luck.

64 Greenbrier
64 Spyder (needs restoration)
65 Corsa 140, restored
66 Corsa turbo, restoring now
66 Corsa 140 "RR" code coupe fully restored
67 Pontiac GTO restored
69 Corvette 427 convertible restored
2004 Caterham R400 (Lotus super7)my race car
2015 Porsche Panamera S
2015 Corvette Z06
1965 AC Cobra (Factory Five)

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: JimBrandberg ()
Date: August 07, 2017 09:31AM

Things seem to be way different this morning. It seems to be way rich on the Primary, perhaps through the accelerator pump circuit.
Even though the air going through the secondary is minimal, it won't hardly run when I block it off with the palm of my hand.
There's no fuel filter in the inlet, I wonder if that might affect the Weber's sensitivity to fuel pressure.
I will certainly follow up when I know more for folks who Search later. Thanks for help so far.
Jim Brandberg
Isanti, MN
CorvairRepair.com

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: thewolfe ()
Date: August 07, 2017 10:01AM

Do you have a wideband o2 sensor? If not I would recommend installing one. It will make tuning that weber much, much easier. The idle speed will need to be over 1k. You won't be able to make it idle well under that. At least mine never would. Both primary and secondary idle circuits are used even with the progressive mod so if you block one it is going to have an effect. Try turning the idle screws in some so it isn't so rich and keep that idle speed up.

Nate Wolfe
Portland OR
65 Corsa 180

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: JimBrandberg ()
Date: August 11, 2017 04:56PM

It's way rich through the Main Jet circuit when it should still be in Transition circuits. It's actually dribbling fuel. I believe the fuel pressure and float (bowl) level is okay.
I'm waiting for an old Weber guy to get back to me. I'm trying to be patient since I'm pretty much a charity case.
One thing I see different from Corvair people's recommendations is F2 rather than F16 Emulsion tubes. Anyone have something to weigh in concerning that?
I can't help but think that running 6 cylinders of air through a throat designed for one would make for some pretty different calibrations from whatever it was used for in it's original life.
I wish I would have just ordered some F16 tubes a few days ago.
Jim Brandberg
Isanti, MN
CorvairRepair.com

Options: ReplyQuote
Re: Weber 45 DCOE Turbo Tuning
Posted by: 63turbo ()
Date: August 11, 2017 06:46PM

F16 emulsions on both the primary and secondary is fine. I guess you have F2's?
that would probably explain the richness at idle, assuming both throttle plates
really are level with one another. I was never able to get a good stable idle
by using only the secondary to move both plates, as there was always a little
bit of tweaking of the secondary throttle stop. It was much easier to open the
caps that cover the progression holes and simply set both throttle stop screws
so that the back edge of the throttle plates were at the front edge of the first progression hole. Then start the car, and fiddle with the idle mixture screws. Those F2 emulsions might be frustrating your attempts to get the idle right though... they really will turn the main circuit into a on/off light switch, requiring hardly any vacuum to come on. To test that idea, you might try temporarily blocking the main circuit on the primary side. I think all it takes to do that is to remove the locking screw that holds the primary venturi
in , and rotate the venturi enough to block the hole in the carb body. See if it will idle then!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote


Sorry, only registered users may post in this forum.
This forum powered by Phorum.