Tuning the 38DGAS on stock 1.9L

[G54B-GT]

PO had installed a 38 DGAS on an otherwise stock 1.9l 72 GT Automatic.
Read somewhere that this is too much carb for a stock motor.
Scanned the thread about the emulsion tubes and the power valve, but don't want to invest time into all that if this is just the wrong carb to begin with.

Anyone know if the 38DGAS can be effectively tuned on a stock motor????

[opelwasp]

It is a pain to tune for a stock motor, it is way too much for it. But it is a good excuse to get a motor that can handle it.

[tomking]

Or I will trade you for a good Solex.

[jvandyke]

That 38 is probably worth at least $200, I watched the market all summer and ended up getting one off ebay for $170 and considered that a good deal. I suggest seeing about trading it for a 32/36 and a bag of chips.
BTW
I lost the electric choke "gasket" plate (plastic disk that fits between choke element housing and carb body). What's a good source for a part like that?

[RallyBob]

It's not 'too much' carburetor, I've done a ton of 38 DGAS' on stock engines, even with automatics and low compression, dating back to 1984.

But it is significantly tougher to tune on a stock engine. The automatic amplifies any bad tuning, it has to be 'just right' or it will be a PITA to drive.

Bob

[G54B-GT]

Originally Posted by RallyBob It's not 'too much' carburetor, I've done a ton of 38 DGAS' on stock engines, even with automatics and low compression, dating back to 1984. But it is significantly tougher to tune on a stock engine. The automatic amplifies any bad tuning, it has to be 'just right' or it will be a PITA to drive. Bob

For a rookie opeler would you recommend a different carb?
This car ultimately will be driven by my mother who will not be comfortable in a tempermental car.
I was looking to switch to a 32/36 for driveability and reliablilty.

Thanks for your input.

[RallyBob]

Originally Posted by G54B-GT For a rookie opeler would you recommend a different carb? This car ultimately will be driven by my mother who will not be comfortable in a tempermental car. I was looking to switch to a 32/36 for driveability and reliablilty. Thanks for your input.

A 32/36 is simpler by far. Unless you have the box of jets, time, knowledge, and patience to rejet the 38 DGAS properly, then I'd suggest the 32/36 DGV instead. But I was just trying to clarify that the 38 DGAS is a viable option and can be made to work, even if it's not the correct choice for everyone.

[opellane]

I owned my GT now over 13 years, and had C & R Small Cars ( Bob) install a Weber 38 on a nearly stock motor.( Thanks, Bob) I like it because dual butter fly action. both barrels open at the same time for increase power. I installed electric fuel pump to stop vapor lock. and jetted down the mains to 135 and the air corrector 160 and been running great for years. Would never go back to 32/36
This is as much power you can get without going FI.
I would Trade you for a nice 32/36 if your 38 is not in too bad of shape.
Mike

[G54B-GT]

Thanks for all the feedback, I have been working with hrcollinsjr (opeler) on a swap for his 32/36.

If this were mine I would tune the 38 for max. power and run with it, but for my moms little grocery getter she doesn't need the extreme.

I Will let you all know how it works out as well as posting pics of the build up on her car!

[oldopelguy]

You know, in Denver you might actually have a better chance of it running well than those of us down low would. Not that I could help you tune it, but it makes sense that if you were going to use that carb on a stock motor anywhere, it would be up high where less actual would get sucked through it.

[G54B-GT]

Originally Posted by oldopelguy You know, in Denver you might actually have a better chance of it running well than those of us down low would. Not that I could help you tune it, but it makes sense that if you were going to use that carb on a stock motor anywhere, it would be up high where less actual would get sucked through it.

I was thinking that the problem would be not enough air here. Since the 38 is not sequential you are just dumping a "ton" of fuel in with not enough air to mix with.

I assumed a sea level guy with the added atmospheric air pressure would have a better chance.

Is there a flaw in my logic??

[opelnut_1]

G54b-gt, I am in colorado as well an had a place in Boulder called slipstream auto tune duel 40's on a volvo. you might see if there still around I think they can set up any weber on any car for any application. just a thought

[G54B-GT]

Originally Posted by opelnut_1 G54b-gt, I am in colorado as well an had a place in Boulder called slipstream auto tune duel 40's on a volvo. you might see if there still around I think they can set up any weber on any car for any application. just a thought

Thanks for the tip! If I get stuck I'll look 'em up!

[RallyBob]

Originally Posted by G54B-GT I was thinking that the problem would be not enough air here. Since the 38 is not sequential you are just dumping a "ton" of fuel in with not enough air to mix with. I assumed a sea level guy with the added atmospheric air pressure would have a better chance. Is there a flaw in my logic??

Sort of...a 'bigger' carburetor is bigger in the sense of larger throttle plates. Therefore it administers more air. Fueling is strictly an issue of jetting. In other words, I can make a stock Solex run pig-rich if I wanted by rejetting, and at the same time I could stick a 4-barrel Holley 850 double pumper on there and make it run lean on a stock Opel just by changing jets.

Extreme examples, yes, but the thing to remember is a bigger carburetor means more air, not more fuel. Fuel is always adjustable regardless of the carburetor size, whereas the air is restricted by the carburetor size itself.

Bob

[G54B-GT]

Originally Posted by RallyBob Sort of...a 'bigger' carburetor is bigger in the sense of larger throttle plates. Therefore it administers more air. Fueling is strictly an issue of jetting. In other words, I can make a stock Solex run pig-rich if I wanted by rejetting, and at the same time I could stick a 4-barrel Holley 850 double pumper on there and make it run lean on a stock Opel just by changing jets. Extreme examples, yes, but the thing to remember is a bigger carburetor means more air, not more fuel. Fuel is always adjustable regardless of the carburetor size, whereas the air is restricted by the carburetor size itself. Bob

I understand, thanks for the help.
If I had lots of time I would like to play with it, but I just need to get it ready for my mom ASAP so I will just swap the carb and try that.
Again, thanks.