New Crate GT-40 Webers Carb setup

[bmace]

Pleased to find your CC site.....here goes 1st post

Im running a Crate GT40 T56 6 speed and have prob with the low end off idle
with my IDF48's on base setting idle is fair except when temps are running hot then it becomes rather crappy. I then get backfiring through the stacks off & on untill I reach approx 2500-2800 & then it pulls steady & smooth.

I'm still reading all the redline/Inglese stuff but was wondering if anyone has been through htis in hopes you might recommend idle jet sizes along with any other help . much appreciate any adv Sincerely bmace

[zrayr]

Originally Posted by bmace

Pleased to find your CC site.....here goes 1st post

Im running a Crate GT40 T56 6 speed and have prob with the low end off idle
with my IDF48's on base setting idle is fair except when temps are running hot then it becomes rather crappy. I then get backfiring through the stacks off & on untill I reach approx 2500-2800 & then it pulls steady & smooth.

I'm still reading all the redline/Inglese stuff but was wondering if anyone has been through htis in hopes you might recommend idle jet sizes along with any other help . much appreciate any adv Sincerely bmace

is your cam Weber friendly?

Z. Ray

[Brent Mills]

That's either the cam with too much overlap as Z. Ray suggests or it's a lean condition. The only reason I shy away from it being too lean is because you note that it starts happening after things are warmed up, which tends to make the A/F ratio go more rich. Maybe post your cam specs and your carb specs (idle/main jets, chokes, correctors, etc, etc).

[bmace]

Originally Posted by Brent Mills

That's either the cam with too much overlap as Z. Ray suggests or it's a lean condition. The only reason I shy away from it being too lean is because you note that it starts happening after things are warmed up, which tends to make the A/F ratio go more rich. Maybe post your cam specs and your carb specs (idle/main jets, chokes, correctors, etc, etc).

Sorry.....idle jets are 55ml,air corr 180m, main 150m, chokes 40m

[68gt500]

I would recomend gtting a wide band o2 sensor setup, like the Innnovate LC-1.

It takes away most of the rich lean guessing and allows you to pinpoint the sources of drivability issues.

Do you have the 3rd transition hole drilled ? On my setup it made a world of a difference.

[bmace]

Originally Posted by 68gt500

I would recomend gtting a wide band o2 sensor setup, like the Innnovate LC-1.

It takes away most of the rich lean guessing and allows you to pinpoint the sources of drivability issues.

Do you have the 3rd transition hole drilled ? On my setup it made a world of a difference.

68GT500
Pardon my ignorance..........pls explain "drilling 3rd transition hole" thks bmace

[zrayr]

Originally Posted by Brent Mills

That's either the cam with too much overlap as Z. Ray suggests or it's a lean condition. The only reason I shy away from it being too lean is because you note that it starts happening after things are warmed up, which tends to make the A/F ratio go more rich. Maybe post your cam specs and your carb specs (idle/main jets, chokes, correctors, etc, etc).

Brent,

do you know the cam spec parameters for using Webers ?

thanks,

Z. Ray

[G.R.]

Ideally a 50/50 camshaft is recommended. Not to say that if you have a "hot" cam with a lot of overlap, a thumpty-thump sound when at idle, that Webers won't work, they'll just be a PITA to get into tune and run properly though if it is a "radical" cam as some people run you may never get Webers tuned up.
I have a 289 with a mild cam just slightly hotter than stock and Webers.

[ENTDOC]

40 chokes are too big for a small block,go with 37's max, this should help your low end and off idle characteristics

[Terry Brown]

Would you think 40s are too big if the SB is stroked to 408 or 427?

Tks

[bmace]

Originally Posted by ENTDOC

40 chokes are too big for a small block,go with 37's max, this should help your low end and off idle characteristics

Thks Entdoc for the choke adv. I agree as local weber gurus
have mentioned similar ideas. much appreciate you input.

Sincerely
bmace

[ENTDOC]

Terry, 40's may be fine for those applications at least for the 427 stroker. Many feel 40's are too big for even a stroked 427so,that has not been my experience at all and seems to cure the over rich situation . I do think they are too big for 302's however.