'91 305 TBI T5....got a tach today to replace my factory that doesnt werk.

Whats the best rpm to shift at? 4500?

 

TBI makes that a fairly difficult question, in truth. TBI unfortunately has a difficult time "breathing" well at higher RPM's, so it'll depend on your car's setup.

 

Stock.... what are the STOCK rpm shift points that work best?

 

most people see their best results shifting at or around 5000 with the stock cam.

later
tim

 

With the stock peanut cam and heads that can't flow past 4500rpm, I beat the most people shifting at 3500rpm. It might seem a bit low, but it brought the engine back into the torque peak.

 

teh best use your senses way is to let the engine pull through the rpm band (dont go past 5500 rpms at most) and concentrate on how the engine feels. When the engine stoppes pulling and the accel. drops off, your past the point where the power band peaks and begins falling off. Shift at the point right before the accel. seems to die off and you should be hitting your peak power output.

 

I've been playing with it and 4500 seems about the best.

 

with the mods I have, first gear seems to pull good until 5000, then I shift at about 4600, and about 4600 again for third, I have an auto and very few mods, if you shift before 4000 I'd say that it is a waste of time

 

What do you feel the best shift point is now with the new cam and heads?

Darrell

 

Well it doesn't have Ultimate TBI mods, AFPR or modded chip and I generally shift at 6000rpm because it seems the most comfortable. It will pull to 6500.

 

If I remember you still run the stock intake don't you?

 

Yup, but I have an Edelbrock waiting to be installed when I get some free time.

 

this sounds like a butt dyno festival
i think we shoudl keep this to people who have track comparisons of what shift points worked for them.
my comparison worked out the same when my car was stock and when it was modded. it shifted itself around 4400-4500 for both shifts, when i shifted at 5000 for both shifts i ran 2.5-3 tenths quicker with a slightly higher mph, maybe 1mph.

later
tim

 

with my old mods I ran a best of 15.854, shifting at 5000 then 5000 again, at about 4400 (second shift) I lost a tenth and a half

 

my car has GTeched faster shifting at 5000 manually

 

5600 is where my shift point is....don't know if that's what my tach is reading but it works for me. You want to go past your peak torque/power but before it nose dives (from not having strong enough springs and/or the lifter hydra-rev setup). If you've taken enough calculus you can understand the whole integral thing. You don't want to shift according to torque (that's more torque converter specific), you want to shift so that you've got the most area under your hp graph from when and where you shift to where it falls back down too.
Example: well I'm too tired, if you need me to show you visually just say so or else I'll asume you all understand what I'm talking about. nap time...zzzzzzzzzz

 

Hooray for area under graphs! Hooray for integrals! Hooray for Calc 1, 2, and 3!

I run about .1 faster when I let my engine spin to 5000, but I let it shift automatically for consistancy. Got an auto, minus well use it.

 

zzzzzz.....that's what reminds me of Calculus class....zzzzzzz