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Old 06-23-2020, 11:17 AM   #1
StompNDump
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Default RPM drop while on Stop

Running an APD Max Speed carb with built in stop and ive noticed on my logger that the car will drop roughly 100 to 120 RPMs while on the stop. Is this normal or has anyone else had this issue.
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Old 06-23-2020, 12:04 PM   #2
J&S Racing
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Default Re: RPM drop while on Stop

Max speed a great piece but very finicky imo..

Are you running a 02?
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Old 06-23-2020, 12:40 PM   #3
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Default Re: RPM drop while on Stop

Not running an 02 just yet, have a set up coming.
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Old 06-23-2020, 12:51 PM   #4
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Default Re: RPM drop while on Stop

Does the RPM drop coincide with the shift?
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Old 06-23-2020, 12:55 PM   #5
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Default Re: RPM drop while on Stop

It doesn't appear to coincide with the shift.
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Old 06-23-2020, 01:18 PM   #6
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Default Re: RPM drop while on Stop

Quote:
Originally Posted by StompNDump View Post
Not running an 02 just yet, have a set up coming.
02 is a absolute must for this carb!!! Make sure you place them 12ish” off the head.

More than likely its your front jets.
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Old 06-23-2020, 02:16 PM   #7
StompNDump
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Default Re: RPM drop while on Stop

Whats your recommendation of what I should try with the front jets?
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Old 06-23-2020, 04:50 PM   #8
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Default Re: RPM drop while on Stop

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Originally Posted by StompNDump View Post
Whats your recommendation of what I should try with the front jets?
I don’t have my log book handy and I only made a few hits last year so I Just can’t remember what way you gonna go for the loss of RPM. Really need to see what the A/F is doing on the stop.

Until you get the O2s I’d play it safe and start by giving it more fuel and see what it does. If it gets worse go down a few sizes from what’s in there now.

For the most part the front jets control what its doing on the stop then you tune the restrictors behind the power valve and rear jets for down track.
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Old 06-23-2020, 04:52 PM   #9
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Default Re: RPM drop while on Stop

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Old 06-24-2020, 01:02 PM   #10
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Default Re: RPM drop while on Stop

need to go smaller on front jet

what is your current setup? main jets front and rear and restrictor sizing in front?

Last edited by sully3358; 06-24-2020 at 01:04 PM.
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