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Carb Accelerator Pump Tuning Question

Posted By: tywebb2

Carb Accelerator Pump Tuning Question - 05/24/09 03:25 AM

I have been wrestling with tuning my 825 Mighty Demon for a while now (in hopes of making it to the track this month?). I have a pink cam in the primary and green in the secondary with 35 squirters. Cruising down the road I floor it for WOT#'s and I get a short trough in my AFR graph that dips down into the mid 10's. Would you say that means I should drop the squirters back to the stock 31's or switch back to the more gradual pink cam on the secondaries....or something else?

By the way...any opinions out there on what WOT and idle (in drive) AFR#'s I should be shooting for. I think I am close with 13.0-13.2 WOT and 13.8-14.2 @ idle in drive.
Posted By: CJK440

Re: Carb Accelerator Pump Tuning Question - 05/24/09 09:44 AM

With a quick stab of the throttle to WO, the overload spring in the pump linkage compresses while the diaphram "catches up" so the cam change won't show much change if at all on your meter. Drop the squirters down and see what happens.

In the end its all how the car behaves.
Posted By: VanishPt

Re: Carb Accelerator Pump Tuning Question - 05/24/09 11:57 AM

Been down this road before..I think you are on the right track. Try 31's.
Posted By: Cab_Burge

Re: Carb Accelerator Pump Tuning Question - 05/24/09 04:44 PM

Quote:

I have been wrestling with tuning my 825 Mighty Demon for a while now (in hopes of making it to the track this month?). I have a pink cam in the primary and green in the secondary with 35 squirters. Cruising down the road I floor it for WOT#'s and I get a short trough in my AFR graph that dips down into the mid 10's. Would you say that means I should drop the squirters back to the stock 31's or switch back to the more gradual pink cam on the secondaries....or something else?

By the way...any opinions out there on what WOT and idle (in drive) AFR#'s I should be shooting for. I think I am close with 13.0-13.2 WOT and 13.8-14.2 @ idle in drive.


I would use and do use the squirters to get the best 60 ft. times, my current motor idles at 14.8 to 15.3 AFR. Nice clean idle: thumb: WOT is a little above 13.1 to 13.3 AFR currently, I still need to experiment with the jetting to find what AFR is best for the fastest for the best 1/4 MPH
Posted By: 67HEMI

Re: Carb Accelerator Pump Tuning Question - 05/24/09 06:50 PM

My car seems to have the best performance at 12.6 to 12.8 in the lights.
Posted By: tywebb2

Re: Carb Accelerator Pump Tuning Question - 05/25/09 02:26 AM

I tried the 31 squirters today and they seemed to help. I will probably put the pink cam pack on the secondary side as well because there is still a little dip down to a low 11..but not bad at all. Wouldn't even notice it if I didn't have the laptop hooked up to it.

I also bumped my HSAB's down to .034 from.039 today and that got my WOT to 12.6-12.9 (started in 14-15 range before timing, jet, and hsab change)so I think I am ready for the track now
Posted By: VanishPt

Re: Carb Accelerator Pump Tuning Question - 05/25/09 10:48 AM

what unit do you have? I use the LM1
Posted By: Georg

Re: Carb Accelerator Pump Tuning Question - 05/25/09 10:52 AM

Quote:

I have been wrestling with tuning my 825 Mighty Demon for a while now (in hopes of making it to the track this month?). I have a pink cam in the primary and green in the secondary with 35 squirters. Cruising down the road I floor it for WOT#'s and I get a short trough in my AFR graph that dips down into the mid 10's. Would you say that means I should drop the squirters back to the stock 31's or switch back to the more gradual pink cam on the secondaries....or something else?

By the way...any opinions out there on what WOT and idle (in drive) AFR#'s I should be shooting for. I think I am close with 13.0-13.2 WOT and 13.8-14.2 @ idle in drive.




When it`s Demon carb, I suggest to call Don to FBO Systems. He`s the man of Demon carbs and ignition tuning!
www.4secondsflat.com
Posted By: tywebb2

Re: Carb Accelerator Pump Tuning Question - 05/25/09 12:33 PM

I have the Zeitronix AFR Meter.

Don sold me the 10* bushing for my MSD distributor so I could get my initial timing up. I actually sent him an email last night with my specs and carb AFR#'s to get his opinion on if it may be a touch on the large side for my set-up. We'll see what he says?
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