[Letsrock]

Working on 565 BBC, carb, methanol......trying to get this alittle more consistent, passes in the heat of the day with bad air & around 6000 DA car runs faster, we can't seem to get it to follow the air, good thru the afternoon till around 6:00 pm then its the witching hour, will run slower, ie... 9.16 thru the after noon ... then then throws down a 9.22..... hour later starts the other way .. a 9.18...... 60's are close, da is with in a few hundred, and temp is within 5.......also car is at close to 200 after the pass in the pits, could I need to go up on the jetting? maybe lean?
Running 202's now , any suggestions would be great

 

[Ryan Tucker]

What size carb? N/A, power valves?

 

[Letsrock]

Its an APD 1150, they just went thru it top to bottom, don't know what the PV's are, came back w/196 jets.......

 

[Uncle Paul]

With that DA a air bleed change might be called for,, Check with APD.

 

[The Bozman]

was it built for 6000 DA? how much humidity and when does it come in and leave?

 

[Letsrock]

was it built for 6000 DA? how much humidity and when does it come in and leave?

Have been on the phone with APD, last go around they suggested throwing out the fuel log and go direct to the carb ports, did that, same results, the carb is ok at 6000, which is pretty common here, when it throws out a slow number, not much or hardy any changes in humidity, we watch it pretty close, last weekend 3 rounds in the dead heat in the afternoon, same numbers, @ 6-7pm air is starting to get better, runs slower .......by 5 or more... its all in the 660ft -finish line where its changing

 

[acs55]

first off car wont follow the da unless its a drastic change .
fuel ,carb and manifold,run time to temp.#1
dew point /grains of moisture per cube of air they find a known stagnate point with alky cars . #2

if car picks up a ton if you keep it off/cold and force it to temp right at the water box your fat.
6000 DA should be 10 jets leaner than 000 .or more
if your not running enough timing for your chamber it will act goofy with moisture too

 

[Letsrock]

first off car wont follow the da unless its a drastic change .
fuel ,carb and manifold,run time to temp.#1
dew point /grains of moisture per cube of air they find a known stagnate point with alky cars . #2

if car picks up a ton if you keep it off/cold and force it to temp right at the water box your fat.
6000 DA should be 10 jets leaner than 000 .or more
if your not running enough timing for your chamber it will act goofy with moisture too

Running a gas primer down the staging lane to 185 on the temp, wack the meth pump on, burn out, make the run... return lane & at the pits temp is near 200....... w/32 deg of timing

 

[jpatt87]

That seems really hot for a car running meth isn't it.

 

[Uncle Paul]

How much timing and what do the plugs look like?

 

[Letsrock]

How much timing and what do the plugs look like?

32 on the timing, plugs look fine

 

[acs55]

how do you stop the carb from pulling fuel while on "primer" ?
i used a lean out ball valve .set idle at 1100 and valve was good to 2000 to put heat in it and keep signal to t-slot and idle circuit low .
have had some primer plus set ups on injected cars run with fuel shut off valve closed to build heat .
its time to read some plugs .you forcing it hot and putting it on alky right at the burn out .then it picks up 15* by the time your back?
does it spike this 15* at the stripe and wont cool off on return road while on alky?
sounds like its way lean but i cant see how with that da and jet . something is missing

 

[Letsrock]

how do you stop the carb from pulling fuel while on "primer" ?
i used a lean out ball valve .set idle at 1100 and valve was good to 2000 to put heat in it and keep signal to t-slot and idle circuit low .
have had some primer plus set ups on injected cars run with fuel shut off valve closed to build heat .
its time to read some plugs .you forcing it hot and putting it on alky right at the burn out .then it picks up 15* by the time your back?
does it spike this 15* at the stripe and wont cool off on return road while on alky?
sounds like its way lean but i cant see how with that da and jet . something is missing

Its like Ron's primer plus, but instead of the spacer, its tapped thru the manifold below the carb, I asked them the same question, said it wouldn't run fuel w/pump off, we run it dry before hitting the meth, doesn't spike, but doesn't cool back down on the return road
stop to pick up the ticket, back to the pits its 200.......our old set up (496) would cool down on the return rarely every saw 190 even in 95 deg weather & back to back rounds......sounds lean but already has alot of jet

 

[Horndog]

32 on the timing, plugs look fine

Seems a little low imo.

Is the water pump running the whole time the engine is?
Are you sure the water pump hasn't taken a dive?

 

[rosco15]

Working on tuning my Meth carb also. What is the best lambda reading as far as consistency goes?

One thing I've found on mine. 1/2 turn out on the 4 corner screws is 200 by the time i'm back at the trailer with the fan on. 1 full turn out and I'm right around 185 and I never have to run the fan.

 

[Horndog]

Tuned by water temp only. Have no clue what lambda reading is best or even if it can be used for alcohol.

What is the engine temp when you stage?

 

[Letsrock]

Seems a little low imo.

Is the water pump running the whole time the engine is?
Are you sure the water pump hasn't taken a dive?

I only run the pump & fan after the temp is in, usually just before the box, yea the pump is working , brand new

 

[Letsrock]

Tuned by water temp only. Have no clue what lambda reading is best or even if it can be used for alcohol.

What is the engine temp when you stage?

180-185 at the box

 

[Letsrock]

Working on tuning my Meth carb also. What is the best lambda reading as far as consistency goes?

One thing I've found on mine. 1/2 turn out on the 4 corner screws is 200 by the time i'm back at the trailer with the fan on. 1 full turn out and I'm right around 185 and I never have to run the fan.

This is the same way, haven't turned them out yet, my main problem is from 660 to the finish line, typical witching hour DA comes down 6-7 pm loses 4 numbers, really think its a fuel restriction problem, what regulator are you running?

 

[Letsrock]

What regulator is anyone using? We have a Holley on it now, thinking to change to a Magna Flow