So having car tuned, showing pumps at 100% duty cycle at 3k rpm, looking at the log I see the voltage is at 12.88v at 3k rpm and gets no higher then 13.02v when I let off at 4500. Any higher then 4500 rpm and car falls on its face like it’s out of fuel. Car is full bolt on with 2.76 upper 9.1” lower and has as far as I know aftermarket pumps in the tank, as tuner tried with stocks pumps for first baseline tune and car was very unhappy. Fan low voltage cause the issue I’m having? I read in a different forum that it can, but only one person made the comment no one else. Let me know what you guys think!
What’s your Voltage at wot during a pull
- Thread starter bschuetts92
- Start date
Yeah. Low voltage can cause the issues you're seeing. I think mine stays above 14 the whole time. I'm running KMJ 250 amp.
Thank you! I’m gonna look into that alternator!
A good alternator will be 14v+ during a pull. Upgrade your alternator for sure. You may still need a fuel system but the increased voltage will help.
I have a fuel system and kb 2.8lc on the way as well, but wanna do this at the same time just as insurance to nip all bs out lol
Has the body ground from battery to radiator support been upgraded?
I found on ours battery voltage was different from on battery reading 14.1 to 12.8.-13.3 on inside car reading .
Upgraded wire did fix it
I found on ours battery voltage was different from on battery reading 14.1 to 12.8.-13.3 on inside car reading .
Upgraded wire did fix it
Old log, but see attached. I have volts and RPM checked. Basically 13.7V.
I’m actively working out how to address this problem preemptively on my cobra as well. I’m deciding to run a Nation’s 200 amp alternator. Has an external Voltage Regulator to prevent premature alternator failure as the OEMs and most basic ones (PA performance is a common brand that has a mixed success rate) have internal Voltage Regulators which get hot due to alternator location and lack of cooling. It’s just a flaw of the era.
It also seems that once you cross the 200 amp threshold you have to consider the big 3 upgrade kit. Basically a bunch of 0 gauge wiring that replaces your ground wire on the chassis, power wire and ground from battery to chassis. That combination of modifications seem to ensure the elctrical system will run as required to keep voltage at 14V at WOT and prevent lean conditions from lack of power to the fuel system. From there recommendations as stated above like FPDM wiring upgrades would help bulletproof the fuel system electrically speaking.
It’s a bit of a rabbit hole but one that I consider vital to ensure the car is getting the power it needs for the car to keep fuel flowing under all conditions to keep the motor safe.
It also seems that once you cross the 200 amp threshold you have to consider the big 3 upgrade kit. Basically a bunch of 0 gauge wiring that replaces your ground wire on the chassis, power wire and ground from battery to chassis. That combination of modifications seem to ensure the elctrical system will run as required to keep voltage at 14V at WOT and prevent lean conditions from lack of power to the fuel system. From there recommendations as stated above like FPDM wiring upgrades would help bulletproof the fuel system electrically speaking.
It’s a bit of a rabbit hole but one that I consider vital to ensure the car is getting the power it needs for the car to keep fuel flowing under all conditions to keep the motor safe.
I’m doing a fore fuel system and a larger alternator as well as a kb 2.8
JMO, but even a stock alternator can benefit from the big 3. At least that's what I told myself when I did it to mine.
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I can see similar voltages with nations and j2 with upgraded cables (sensing wire in stock location). You have enough voltage to make a clean pull, ur pumps are junk (Probably not turbine style duty cycle pumps) and or not getting enough voltage (get a BAP). Get some proper pumps/BAP or go with a return style setup.
I did the fore return style system! Thank you for the into! Greatly appe
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