engineermike
Well-Known Member
- Thread starter
- #1
2018, whipple stage 2, a10, whipple cal only.
Has anyone played much with true pump gas and pullies? My results are as follows....this is on straight 93 with no octane booster, 4th gear pulls.
On the supplied 3.875 pulley and stock thermostat, my timing hits 17 deg at about 5300 rpm. It might bump 17.5 at 6000, and sometimes touch 18 at 6500. I guess heat takes over and it usually starts pulling timing from there. By 6700 it falls to 17-17.5. It might hold 17 to redline, or it might drop to 16.5.
On a 3.75 pulley and 160 thermostat, I see identical timing up to about 6000 rpm (17). From there up, it runs 1/2 to 1 deg less timing vs above, dropping to 16, maybe even 15.5 by redline. I do find it harder to get a clean log with this pulley, as it breaks the tires loose in 4th when it comes into the mid-range.
What are other folks finding? At what point does adding boost not add power due to loss of ignition advance? Is it worth trying the 3.625 on 93? Would it still be safe if I got a bad tank of gas or had to use 91 in a jam?
Thank,
Mike
Has anyone played much with true pump gas and pullies? My results are as follows....this is on straight 93 with no octane booster, 4th gear pulls.
On the supplied 3.875 pulley and stock thermostat, my timing hits 17 deg at about 5300 rpm. It might bump 17.5 at 6000, and sometimes touch 18 at 6500. I guess heat takes over and it usually starts pulling timing from there. By 6700 it falls to 17-17.5. It might hold 17 to redline, or it might drop to 16.5.
On a 3.75 pulley and 160 thermostat, I see identical timing up to about 6000 rpm (17). From there up, it runs 1/2 to 1 deg less timing vs above, dropping to 16, maybe even 15.5 by redline. I do find it harder to get a clean log with this pulley, as it breaks the tires loose in 4th when it comes into the mid-range.
What are other folks finding? At what point does adding boost not add power due to loss of ignition advance? Is it worth trying the 3.625 on 93? Would it still be safe if I got a bad tank of gas or had to use 91 in a jam?
Thank,
Mike
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