i wont be swapping motors till winter, what is the best rpm to shift at and luanch at in my 91 lx 5speed

 

probley the highest it can go

 

once it past 5600 the car dosnt accllerrate any more just contiunes to climb the rpm band, so im gussing around 5600 is where i should shift

 

If it doesnt accelerate past that RPM, thats the right time to change gears I'm pretty sure. Unless there would be some benefit to revving it higher that way when you shift it keeps it in vtec because the revs are higher? Im not sure.

 

When i'm trying to keep v-tec engaged i tend to come down on the gas harder after the gear to keep the revs high then i start up at about 4 grand through every gear? Is this the wrong way to go about things? I also launch at about 3 grand? is that generally where everyone else does. I'm sure there are probably a million and 1 "correct" ways to do it. but i'm just curious...

 

his car has no vtec, shift your accord around 6.5

 

Kevin is correct…A 1991 Honda Accord LX was <U>not</U> VTEC.
It produced (stock) 125 hp @ 5,200rpm
It produced (Stock) 137 lbs of torque at 4,000rpm, …

@ 5,252 rpm, the engine should be producing about 125ftlbs of torque and 125hp (theoretical mathematical model) dropping @12 ft lbs of torque from 4000 to 5,250 rpm. After that, your torque will usually begin to wane very rapidly. (Hence your quoted feeling that it is not accelerating any longer.)

Therefore…I suggest launching @4,000-4,500 ...that should give you a max-torque launch … if you don’t loose traction and I doubt(?) that you will bog.
So, you might want to try that as a ballpark figure and go from there with some trial and error. Note that most max rpm (Banzai!) launches usually only serve to spin your tires and eat up your stock treads…You are going nowhere – fast!…You are getting no traction and that in itself will reduce your times accordingly. You need to 'hook-up! '– A little '‘chirp will usually suffice on stock engines and tires as long as you can remain within the maximum portion of your torque curve.

The gear ratios (if my sources are correct) are:
3.288, 1.777; 1.193, 0.903 and 0.685…(with a final of 4.062) BTW: you don’t need the final gear ration in your calculations.
The actual exact shift point question is beyond the scope of this forum at this time with the given information because you will <U>need</U> a ‘dyno chart’ of your engine to accurately produce those figures.( If someone has a dyno or torque curve chart for this or a similar engine…get them to post it or send it to you !

Then …See http://www.prestage.com/carmath/dynochart.asp

In the interim…
When you do shift, you want the engine to be hitting a point within the maximum (power range) portion on the torque curve in the <U>next</U> gear (with the least percentage of reduction in overall torque).. probably 3,500-5,200(?) - one can only guess at this point. This means that you may not necessarily have to be at red-line for that particular shift. (Your gear ratios will have a lot to do with that…the wider the spacing, the more’fall off’ and usually the less torque produced. I do notice that the 1-2 ratio is 'quite' wide, whereas the 2-3 is bit closer. You may have to wring it out a bit more in 1st, but your guess of 5,600 seems pretty good for the 2-3 and 3-4. Just my opinion!
There was also a minimal discussion of torque vs horsepower in this forum .
https://honda-tech.com/zerothread?id=665934
Good luck!

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"I see it all perfectly now! There are two possibilities, one can either do this or do that. My honest opinion and friendly advice is this: do it or do not do it, you will regret both." . ~Kierkegaard

Modified by Curmudgeon at 1:57 PM 4/15/2004


Modified by Curmudgeon at 2:01 PM 4/15/2004