Picking the shift light setting...

[Paul Workman]

I just installed my Raptor shift light - getting ready for the Crown Point Corvette Challenge on Saturday (hint, hint). Given the dyno graph, picking a shift point rpm seems elementary, no? No.

The dyno graph suggests 7100 as the shift point. However, after setting the light to trigger at 7100, before you can blink, the rev limiter kicks in (I'm guessing it must still be at 7200).

So, question: Those familiar with the characteristics of a 450-500 hp LT5, and you wanted to have the shift occur near 7100 rpm (for now), at what rpm would you set the shift light to allow for human reaction time?

TIA

P.

[LGAFF]

Paul for you I would set it at about 5200

[XfireZ51]

You need your chip re-done with a higher fuel cutoff. I have shift light set for 7200rpm with a 7500rpm fuel cutoff.

Lee,

Are you coming Saturday?

[sammy]

i set mine @6800 rpm which seems to work best for me

[Paul Workman]

Originally Posted by XfireZ51

You need your chip re-done with a higher fuel cutoff. I have shift light set for 7200rpm with a 7500rpm fuel cutoff.

Lee,

Are you coming Saturday?

Higher cutoff setting: Roger that! Still pullin' like a freight train when I hit cutoff! (7500 sounds like a pretty good spot!)

I'm assuming if you set your trigger at 7200 that you are shifting at...something north of 7200...unless you just die your hair silver and have the reflexes of a 14 year old girl??

As for Saturday...I'll ABSO FRIGGIN LOOTLY B there...unless it rains And, Pete is coming and said he'd be talking to Al and Kevin and Bob G later that day (yesterday), & Marc Haibeck said he's planning on being there. Jimmac is "iffy" at this point; no word yet from Lee or Kenny or HDZ Bob. Jeff can't make it, but I haven't made contact with our Austrian extension of the FBI (Jochen and the guys) yet - I doubt they can make it by Saturday, but we'll be wishing they were there, Hans...the one member of the Kalifornia extension of the FBI might not make it (but is always welcome!) I'd say the ZR-1s have a shot at that traveling trophy - good as anybody - better 'n most I recon!

P.

[Paul Workman]

Originally Posted by sammy

i set mine @6800 rpm which seems to work best for me

Thanks for the input, Sammy.

The light I got was out of another 500 hp LT5 car and I believe it was set at 6700...which seems a bit "short" to me. But, I suppose that depends on individual reaction time and rate of rpm acceleration. My reaction time ain't like it was when I was 17, but contrary to my dear friend Lee's suggestion of 5200... I might have gray hair but my reactions ain't that bad...at least not yet!

P.

[sammy]

my pleasure to try to help. at 57 my reflexes have turned to molassis so by shifting where i do it ends up being around 7000-7100 on my gtech pro which i can download a bunch of stuff to my computor to try to improve my times. plus it has a built in shift light . i can see wheel spin off the line launch rpms ,who long i take to shift each gear . its kinda a fun little gizmo. you guys rip their hearts out and have a blast

[XfireZ51]

Anecdotally, my best trap speeds have come from shifting when tach indicated 7000rpm. Based on my observation of shift light v tach seems to be tach is ~200rpm below light. So 7200 shift light sounds about right. Based on my last dyno run, motor is down a few hp from peak at 6750. So a drop of 1000rpm during shift should put me at about 6300rpm and climbing back up power curve.

[Paul Workman]

Originally Posted by XfireZ51

Anecdotally, my best trap speeds have come from shifting when tach indicated 7000rpm. Based on my observation of shift light v tach seems to be tach is ~200rpm below light. So 7200 shift light sounds about right. Based on my last dyno run, motor is down a few hp from peak at 6750. So a drop of 1000rpm during shift should put me at about 6300rpm and climbing back up power curve.

I suspect you are close to ideal; my being at 7100 wouldn't be that much difference, except that fuel cutoff occurs a split second after the timing light comes on...and the rpm slam the cutoff too, I might add. I recon I'll have to live with it tomorrow, but moving the cutoff to around 7500 as you did seems to make a lot of sense!

As always, thanks Dom for your expertise. BTW...Remind me to bring that friggin starter with me tomorrow!!

P.

[BlackWidow#2]

I hope the weather is better this week. I wish I could be there! ;^)
George