Ok, I have a 5th gen, honda tuned the tranny so the rpms stay in vtec when shifting. When I redline in 3rd and shift into 4th the rpm are a few hundred above vtec activation. Now, shifting so the rpms land at the torque peak gives the best acceleration...right? And the torque peak on the H22A4 is at the onset of vtec...right? I found if I shift at 130km/h(don't know what that is in miles/h) rpms land right on the vtec activation point.
What Im tying to say is if you shift earlier in 3rd at 130km/h will you get better times. Has anyone tryed this or even noticed.
I notice the shift hits harder this way

 

From what I've heard you should shift where the torque numbers of the gear you are in and the next gear up are equal. So if on a dyno sheet you have 100 trq at 5500rpm in 2nd gear and you have 100trq at 7300 rpm in 1st gear you should shift at 7300 rpm in first gear. This is what I've heard, has anyone else heard the same? Personally, I just redline the gears.

 

I assume taking the car to near fuel-cut is optimal.


[Modified by Mike95lude, 4:05 PM 1/14/2002]

 

The stock redline is 500 rpm after the stock hp peak though.

 

Are you sure Lauphin? I know mycar will pull all the way up till redline, thats where I shift, peak power is right around 7500rpm, and our tachs are off by a few hundred rpm, so on the tach you shouldnt run out of power until almost 8000rpm. I dont know for sure, just what I have experienced and heard.

 

Its not that H22 run out of steam before redline, its that, in 3rd shifting early makes the rpms land right on the torque peak...at 5250rpm or something like that. I notice it hits harder this way. See what im saying?
....are you the toretto!? its an honor to meet you sir!

 

I'm not sure, it's just what I've heard. Let this post stay at the top for a couple days and we will get some more opinions.
Edit: I don't have my lude on hand to test out this theory either. Does someone else want to try it?


[Modified by laughin2.2, 5:55 AM 1/15/2002]

 

***** please.....

 

If you shift at 7300 though you're very likely to fall out of VTEC. Personally I shift at 7500 (on the TACH) for so-so races, for serious races I shift at 8000 on the TACH.

 

With my experience....On the 1-2 shift I usually shift right at redline, give a 100 RPMs. With some slight wheel spin I can usually manage to keep my car roughly around 5600 RPMs. The 2-3 shift, just before redline, the 3-4 shift maybe 200 RPMs before redline. From what I've heard from my honda buddies, our cars won't make any HP gains once it gets so close to redline (it just makes it easier to stay in the higher RPMs)-- it's almost pointless to take it that high after you've made the 1-2 switch. While your car isn't making any gains for that fraction of a second, the other driver could be making a slightly earlier shift getting a power gain, which puts him ahead that much more over you Best thing you can do is take it to the tracks. The slips tell all....

 

do you own a 4th Gen Prelude S? (Lude w/Accord motor) or a 4th/5th Gen VTEC?
have you taken your car to the track yet? all the people I've known that manage to get 14.5x or 14.6x with just I,H,E drive it *hard* like I described.

the whole idea of shifting at a higher RPM (7400-8000 for VTEC's) is so you'll still be in VTEC when you shift into next gear. If you fall out of VTEC even once it could cost you that extra .2-.4 seconds in the 1/4 mile.

you're right though, you probably wont get anymore power running it at a higher RPM. but look at what your power is when you are at below VTEC RPM's.

example:
shift at 8000 RPM
next gear RPM will at 6000-6500 RPM

shift at 7000-7200 RPM
next gear RPM will be at 5000-5200 RPM

even though you're in VTEC in the second example your HP is pretty low? your peak of 200 HP occurs at 7000? RPM (or is it 7200?).

EDIT: BTW the above numbers are just an exaggerated example, they may or may not be the actual number, but they are very close.

does any one know where I can find a Dyno graph of a stock 4th or 5th Gen VTEC 5 speed?


[Modified by BlueShadow, 3:33 PM 1/17/2002]

 

a little knowledge about how gearing works will help...

take it to the redline in each gear. Gearing multiplies torque. If you make 100 ft/lbs at redline, you are making more POWER AT THE PAVEMENT then you will at peak torque in the next gear.


so even if your torque curve peaks at 5400, then you will pull harder at redline, one gear lower.


I don't have time to get more detailed right now - if you guys don't get it, I'll try to go more in depth later this morning



[Modified by JDM LUDE, 3:10 PM 1/17/2002]