8T1-7T9 BIONIC VETTE

Installed a shift light today with pills from 5200-5400-5600-to-5800.....Engine is max RPM 5800....should I use 5400 pill and be safe, or 5600 pill and play dangerously, or go straight to ludicrous with the 5800 pill? :D :seeya

nunus79

Cappy
Did you get the tach w/playback feature? If you did, see how fast your shift reaction is when playing back. If you shift like me, use the lowest pill :D

63Banshee

Don’t be concerned so much with max rpm as peak HP if you are looking for the best performance. To answer your question, 200 rpm should be plenty of safety margin.

ZD75blue

they make parts to fix em... just make sure you have a blow proof bell housing, gernaded clutches like feet, and if you like yours you'll get one if you dont already have one :jester

ZD :cheers: nice tack

8T1-7T9 BIONIC VETTE

nunus79,
Sorry I did not answer your question...no I did not get the tach.....only the shift light, with pills from 5200-to-5800....I'll try the lowest and work my way up to the explosion....I'll also check out my dyno sheet....should I look for peak torque and hp on the sheet as a shift point? :seeya

7Bob3

Cappy,
Take it out and romp on it in first gear. Watch the tach. You'll pull hard to xxxx Rpm then then it will fall off. Light 200 before it falls off.

8T1-7T9 BIONIC VETTE

Okay 7Bob3,
If I take it to the fall off point will it self destruct? :confused: :seeya

nunus79

Cappy
The forum gurus have said if we keep it under 6000 rpms then we shouldn't be flying parts all over the place. The way that I have been figuring out shift point is by ET. Increased shift points each run until the ET starts to drop. The problem is my ET kept on increasing until I hit my self-imposed 5500 redline. Now that the gurus said I can run till 6000, I'm going to experiment somemore.
Norris

8T1-7T9 BIONIC VETTE

Nunus79,
And here I thought there was some sort of science to this Tach/shift light thing :D

Red73

Where did you mount your shift light? Here is where I put mine. Current pill is 5400.




:cheers: :cheers: :cheers: :cheers:





[Modified by Red73, 9:39 PM 12/5/2001]

7Bob3

No, redline on your cam card is where you will float valves. You will fall out of the power band long before then.



[Modified by 7Bob3, 5:53 PM 12/5/2001]

CDaniel525

I redline around 6000, and shift at 5800 RPM with my shift light which also uses the pills. Id have a 6000 RPM pill in there if i had one, but thats cause im :crazy: whats more fun is powershifting @ 3500 RPMs (WOT) into 2 second gear and doing a burnout like most hotrods do off the line :D






[Modified by 74VETTE, 8:29 PM 12/5/2001]

8T1-7T9 BIONIC VETTE

Red73,
I mounted in the same place as 7Bob3.....Thanks for all the info guys....now lets go out there and blow up some engines :D :seeya

Captain Morgan

I see most of you guys are using a shift light only. Does this shift light work with stock ignition or do you need to buy an aftermarket ignition setup? I still have the stock HEI but I would like to have a shift light if possible.

8T1-7T9 BIONIC VETTE

sharklover,
Green wire to tach wire on HEI....black to ground.....red to any 12 volt power source......You already have Tach then all you need is light. I need light because our track is dark at night. Over 80 mph in the dark...I prefer keeping my eyes on the track ahead and not on the tach for shift point. Things get real spooky at 100 mph in the dark. :seeya

Vetterodder

The purpose of a shift light is to let you know when to shift during a race without having to watch the tach. It should be set at your optimum shift point. The optiimum shift point is the point that provides the best acceleration and doesn't necessarilly have any thing to do with the engine's red line. If an engine has a 6,000 rpm redline but makes peak power at 5,000, it's best shift point is probably closer to 5,500 unless it's power is rapidly falling before then. The only truly accurate way to determine optimum shift points is by making timed runs and experimenting with the results. You may be able to get close by comparing torque and hp graphs vs gear spreads but only actual runs will show the effects of rolling resistance, drivetrain losses, wind resistance, etc.. Also, because the spread between gears may not be the same at all shift points, i.e., 1-2, 2-3, etc., and because rolling resitance and wind resistance are changing as the car increases speed, the optimum shift point may be differerent from one shift to another.

Keep in mind that the recommended "max" rpm as given by the mfg applies to an unmodified engine in good condition. In a stock high performance engine with a high rpm solid lifter cam, their limiting factor might be the limits of the bottom end. In a stock standard engine with a mild hydraulic cam, the limiting factor might be it's valve train's ability. Once those factors have been modified, it's up to the user to use good sense to determine what a reasonable red line is.