How do I pick a TC??
It's slow all right but I think NOT as low as 600 ,lol.
It's lumpier that my 230cam, that's for sure, I'll guess one or maybe two sizes bigger, so 237 to
[email protected], but a slow idle always makes a cam sound bigger that it really is.
BTW; Good job getting the idle into the basement! like that.
I think CCP (cranking cylinder pressure) is a bigger indicator to selecting a stall.
If yur running 190 psi, with those 4.10s, she won't need much of a stall at all.but
If yur running 145psi, with 3.23s; oh lordy .
Plus since the beast is already on the road, I think
@12many said it best.
I couldn’t get any faster than mid 14s.
What was the mph, car weight, and elevation of the track? These numbers can be translated into horsepower. From the power numbers and weight, an approximate fastest ET can be generated. Then you just have to spend,spend,spend, to get close to it.
I like to putt around town, drop the hammer every time no one is around and run it at the strip a handful of times a year.
This is an exercise;
In First gear, with 4.10s, and 27s, 30mph is already 3750@zeroslip, say 4150@WOT . A stall of 4200, from this point on, is not gonna make a difference, especially if it spins.
In First gear..... 20mph is 2500@zero-slip, say 2800 @WOT. I'd be surprised if the tires didn't spin, the CCP would have to be pretty low. So again, a stall would Not help much if at all.. But if the tires don't spin well then , a higher stall might help. The thing is that in less than a second, your rpm will be thru the roof as the car finally does break traction.
Now, the 727 has a very wide 1-2 split of .59. Lets say you have a power peak of 5400 and are shifting the 1-2 at 6000. At the shift, your rpm would drop to 3540. So a stall of Less than that will help you nothing, on the shift.
That cam will have a powerband of about say 4200 to 5700=1500rpm.
Whereas the the rpm drop from First to Second is 6000 less 3540=2460. So on the shift into Second, the transmission drags your rpm way way down into the basement, and "off the pipe/cam". In this case you might consider a TC stall of closer to 5400 less 1500=3900, but up to 6000less 1500=4500
But I can almost guarantee you that with the 4500, she is gonna bust the tires loose, after hitting 6000 in first gear, which with 4.10s is only like 40/44 mph.
Now, the 2-3 split is only .69, so your shift rpm can be say 5800 on a 5400 power peak. Therefor, on the shift at 5800, the Rs will drop to 4000, so a 4000 stall will be about right. And she ain't likely gonna break traction at 70mph (5800 in Second).
Conclusion; the 4000 is about right for the track ....... for "the handful of times a year", that you might go.
But on the street, WOT with a 4000TC, will result in nothing but tirespin in two gears, so "dropping the hammer" is sortof a thing of the past..... unless you swap out that 750DP...... lol. Ima thinking 500AVS or a small TQ; these are adjustable Air-Valve Secondary carbs, with which you can soften the hit, and slow things down, for less tirespin.
I mean that car sounds like it could do Zero to 60 in about 5.2 seconds. What's the difference if it goes 5.2 spinning and sideways, or 5.4 straight as an arrow.
Caution, all the above numbers are fictitious and bear no resemblance to anything in reality ...other than the 727 ratios which are 2.45-1.45-1.00.. This is just an exercise.
