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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

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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.

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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

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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.

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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

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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

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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



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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)

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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

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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

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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

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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



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Re: Weber 45 DCOE Turbo Tuning
Posted by: JimBrandberg ()
Date: September 23, 2017 05:30AM

I thought I'd follow up with how it came out in case someone does a search.

Regarding the idle circuit. Most Webers use 1 1/2 turns out as a starting point for idle mixture screws. With research we found our Model 152 and another model were okay with 3 turns or more out. Our carburetor came with F8 65 idle jets, They may have been okay but I drilled them out a little and they were then too rich. We tried F9 50 and they were too lean, much hesitation when trying to get underway. We settled on F9 60. The Weber idle circuit has 2 more progressions so it is responsible for more than just idling.

For Main Jet circuit we were advised that a rule of thumb to begin is Air Correction jet numerically 30 higher than Main Jet. We went with 160 Main Jets and 190 Air Jets. We changed from F2 Emulsion tubes to F16.

With the vacuum secondary conversion we were advised that idle stop screw on Secondary only was sufficient for both. We added one to the Primary too. We got it idling at low RPM with no contact on the idle stop screws by adjusting the mixture screws only. They're both at about 3 1/2 turns out but as stated 1 1/2 turns neighborhood is normal for most Models. When we got the best idle with the mixture screws, we added just a bit with the stop screws to bring the idle RPMs up a bit. It didn't take much, maybe 1/2 turn. There is a screw on the bottom of the Secondary "box" to adjust the spring, I didn't fiddle with that but the owner did a little.

I wish I knew why were getting fuel out of the Main Jet circuit when it should have been just running on the Idle jet circuit. All of a sudden it just started working. I think switching from F2 Emulsion Tubes to F16 helped but I can't be certain. While happy with the outcome my analytic mind is not satisfied, you know the old try one thing at a time and record the outcome thing.

The owner is going to do some more tuning, he is experiencing pinging under boost. Probably richer on the Secondary would be the next step. It was running okay and making boost with the Carter YH. It is running better with the Weber and making more boost easier even in 2nd gear with the vacuum progressive Weber. He also has a Safeguard and O2 sensor.

We made a steady bracket from the carb base to the top shroud. I think the assembly is flimsy with just the turbo pedastal and 2 bolts on the head around #5. The Carter YH uses the air cleaner to steady it up. We used the wider K&N filter and drilled a hole in the front for PCV, there just wan't room on the base from behind.

The carburetor does not have a cold start circuit. It was purchsed on Ebay and sent for the progressive conversion which doesn't necessarily include a thorough rebuild and investigation. I believe this particular carburetor had something wrong with it that we somehow corrected during disassembly and investigation, we just don't know what that was.

I kept the original gas filter with return to the tank. I added a Holley pressure regulator with one in and two out. Going from 1/8 NPT on the filter to 3/8 NPT on the regulator required 2 fittings. On one outlet I installed a 1/8 NPT pressure gauge. On the outlet to the carb I went with 6AN Aeroquip. The Holley regulator adjusts with an allen wrench and locknut. I think we're at about 3#s fuel pressure. A fellow could remove the gauge and install a plug if the cheap gauge made him nervous.

I say "we" because my older brother was helping me. He has Weber experience with Caterham 7 Vauxhall and HP Honda. There was a time when he "taught me all I know". I stayed with Corvairs and he decided there were other things.
Beginning Specifications, same on Primary and Secondary:
Weber 45 DCOE Model 152 #0136 Made in Spain.
Venturi 36mm.
Auxiliary Venturi 4.5.
Idle Jet F9 60.
Main Jet 160.
Air Correction Jet 190.
Emulsion Tube F16.
Pump Jet Primary 45 Secondary blocked.

Jim Brandberg
Isanti, MN
CorvairRepair.com

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Re: Weber 45 DCOE Turbo Tuning
Posted by: gnvair ()
Date: September 23, 2017 05:44AM

What a/f ratio are you seeing under boost? I have found stock Corvair turbos to be very lean with a/f ratios over 12.5:1 which can aggravate the tendency to ping. I like it under 12.1:1 and prefer closer to 11.5:1 this especially if you are increasing the boost level away from stock levels on pump gas.
They may not make max power there but they will be a lot less likely to ping, run cooler and safer. You can run them leaner on the jetting at the carb and add alcohol or methanol injection on top and which also makes a very nice difference. This can lower the a/f a full point or more. Straight water doesn't do it for me.

Lee J



Edited 2 time(s). Last edit at 09/23/2017 05:47AM by gnvair.

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Re: Weber 45 DCOE Turbo Tuning
Posted by: tboltkc ()
Date: September 23, 2017 01:07PM

I don't want to hijack this thread, but I am also working on tuning my 45 DCOE.

Engine is 0.030 over with TB-20 cam, I believe an e-flow impeller and crown housing.

This is a new engine on which I am reusing the Weber and turbo. My problem is that it goes super lean - like over 20 - when I snap the throttle open from idle (not driving just sitting there).

It's a progressive with the following setup currently:

Primary Secondary
Choke 32 34
Idle Jet 55-F9 55-F9
Main Jet 135 145
Emulsion 170 175
Accel Jet 45 blocked

AFR looks fine if I rev it slowly, only have the problem when going wide open from idle. Seems like that indicates an accel pump issue, not giving enough fuel, but if you look at the attached picture the one on the right is what I have installed, the other is another one marked 45 that I had. So it looks like someone drilled it out to give more fuel, and I do see a squirt when I look in there. But it seems like a lot of fuel, but just kind of dribbles in there.

Any suggestions?

My setup before was

Primary Secondary
Choke 32 38
Idle Jet 50-F6 55-F8
Main Jet 195 205
Emulsion 160 155
Accel Jet 45(same as pic) blocked

Which seems really wacky but id didn't exhibit this condition but idled at about 9 AFR IIRC.



-Travis


'65 Corsa; '63 Convertible; '62 Wagon; '65 4 Door
Heart of America Corvair Owners Assocation (Kansas City, MO)



Edited 1 time(s). Last edit at 09/23/2017 01:16PM by tboltkc.

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Re: Weber 45 DCOE Turbo Tuning
Posted by: tboltkc ()
Date: September 23, 2017 01:18PM

Having a hard time getting the pic to show.



[1drv.ms]

-Travis


'65 Corsa; '63 Convertible; '62 Wagon; '65 4 Door
Heart of America Corvair Owners Assocation (Kansas City, MO)



Edited 3 time(s). Last edit at 09/23/2017 01:22PM by tboltkc.

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Re: Weber 45 DCOE Turbo Tuning
Posted by: tboltkc ()
Date: September 23, 2017 02:34PM

I looked down the primary barrel while moving the throttle with the ending running. It looks like the fuel from the accel pump is hitting the back of the butterfly. That doesn't seem right or adjustable.

-Travis


'65 Corsa; '63 Convertible; '62 Wagon; '65 4 Door
Heart of America Corvair Owners Assocation (Kansas City, MO)

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Re: Weber 45 DCOE Turbo Tuning
Posted by: 63turbo ()
Date: September 23, 2017 02:46PM

Travis- I had the same problem with mine- the issue with the weber being used on the turbo has to do with how the main circuit and aux venturi are designed to operate vs how the circuit actually comes on. The weber main circuit is designed to work well when the carb is attached close to a intake port on a naturally aspirated engine- theres considerable pulsing with this arrangement,
so the aux venturi is designed with this pulsing in mind. The aux venturi will
not signal the main to come on if the pulse is backwards (from the port through
the carb to the air cleaner) like when reversion is taking place, but if the pulse is going towards the intake port, and there's enough of these "forward" pulses, then the aux venturi signals the main to come on, because there is sufficient pressure drop within the venturi to start siphoning fuel from
the main circuit. Once this siphoning starts... boom! the main circuit dumps fuel down through the aux venturi and the fabulous strong weber main circuit
is in full control. The problem though is that the turbo is slow to react, so
the main circuit on the weber is reacting to airflow and load conditions that were basically present a few nano seconds earlier, not what the engine and turbo could use RIGHT NOW. The solution that I came up with was to more or less
force the main jet on the primary side to come on much sooner than it would normally would by using a much smaller primary, even though the weber rules
would tell you not to go there! on my car, 29mm is what I ended up with- I did
this by taking a 32mm choke and pressing a sleeve in it that had a 29mm id, and a o.d. that was sufficient to produce a slight interference on a 32mm choke. After I did that, the main on the primary was on at only 2000 rpm, and pretty much gave as good a throttle response as could done with a carb. The "delay" in A/F readings when the throttle position was changed was considerably reduced!
On your car, (bigger engine) you might want to try a 30mm choke on the primary
with a 120 or 125 main.
With the accelerator pump jets, the one on the secondary should be blocked the primary hole is normally drilled to be roughly double the area of a single 45 accelerator pump jet- this is done because theres not always enough air flow
on the secondary side to carry gas from the squirt, but there always is enough on the primary. I think that the modified 45 accelerator pump jet would probably work a lot better if it had 2 small holes vs the large single hole that is normally used.

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

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



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Re: Weber 45 DCOE Turbo Tuning
Posted by: JimBrandberg ()
Date: September 24, 2017 06:24AM

I may have missed something but why did you go 60 points lower on the Main Jets?
Jim Brandberg
Isanti, MN
CorvairRepair.com

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Re: Weber 45 DCOE Turbo Tuning
Posted by: 63turbo ()
Date: September 24, 2017 09:39AM

JimBrandberg Wrote:
-------------------------------------------------------
> I may have missed something but why did you go 60
> points lower on the Main Jets?
> Jim Brandberg
> Isanti, MN
> CorvairRepair.com

He said his AFR's were fine when revving it slowly with that set-up, and that
set-up more or less is following the rules for main jet vs choke size... main
jet= 4xchoke size so 4X32=128, and he has 135, which is just fine, and his AFR's when revving it slowly demonstrate that. The weird set-up was what he had
"before" with a 195 main jet with the 32mm choke, and the 50f6 idle jet which probably explains the sick rich idle AFR that he had 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



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