Originally Posted By: wirelessF
Someone should loan you a early-90's Ford diesel for you to test, just to test the max limits.
The GM LS (LQ4) 6.0L no-battery test at NOCO's website is too easy. GM LS engines don't require a lot of cranking power since the compression isn't too high (trucks 9.5:1.) Test it on a high compression engine then it might have a hard time.
Since they specifically say it's for up to a 6.0 engine, i am guessing they did some R&D to know it does have limits around that size.
I would venture to say it could start a larger engine that is low, but not really low on battery. Like maybe one that cranks slowly on its own battery, but not one that just goes "CLICK CLICK"