okay, so i have an excel sheet that tells me the top speed in each gear for any B-series tranny, hydro or cable. so i took that information and decided to use it to find what engine speed you would land on in the next gear if you upshifted 1 gear. i negated any slowing of the vehicle during shifting (i assumed instant shifts) because that would make it very difficult, although that would have minimal effects on the numbers i wanted. i wanted to know what transmission would be the longest you could get and still keep your engine in its powerband. the shift RPM is variable, ie, all i have to do is replace my LS's 6900 with 8000 or any other number i want and the whole table changes. the table has my LS's ratios with 4.40 gears, hydro GSR gears, '98-spec JDM ITR gears, and hydro B16 gears. here is what i found:

upshift #, followed by RPM in next gear
GSR
1-2, 4999rpm in second
2-3, 6076rpm in third
3-4, 6467rpm in fourth
4-5, 6470rpm in fifth

'98-'00 JDM ITR
1-2, 5540rpm in second
2-3, 5895rpm in third
3-4, 6027rpm in fourth
4-5, 6464rpm in fifth

Hydro B16
1-2, 5533rpm in second
2-3, 5888rpm in third
3-4, 6453rpm in fourth
4-5, 6510rpm in fifth

all this is with shift at 8500. what i found interesting is that all GSR 4.40 and ITR 4.785 seem to be very similar. here is the formula is used for 1-2 shift, others similar:
(shift speed of engine)*(top speed in gear 1)/(top speed in gear 2)

1)anybody spot a mistake?
2)is this a revolution in which gears are better
3)does shift time make that much of a difference. every tranny would be shifted at the same time, but shorter trannies would be shifted at lower vehicle speeds meaning it would decelerate less. if #3 is right, shorter gears don't make a damn bit of difference except that you go slower in each gear so you lose less vehicle speed between shifts because there is less rolling and air resistance.

ponder, if you will.

 

interesting

 

isn't it though? it almost seems that the GSR is every bit as close as the '98+ JDM ITR, and the B16 is even better.

 

my .02:

This idea is probably the culprit. VVV

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95lstegman &raquo;</TD></TR><TR><TD CLASS="quote">every tranny would be shifted at the same time</TD></TR></TABLE>

Though your calculations are likely correct, it would seem to me the apparent near equalness of the transmissions is due to not considering when and at what vehicle speed the shifts are occuring. As long as the ratio of (top speed in gear 1)/(top speed in gear 2) remains relatively constant among the transmissions, you will find similar (rpm in next gear) numbers.

Example (made up numbers):

Let's say a b16 hydro from 1st to 2nd is 40/60 or .6667,
and a gsr is 45/67.5, also .6667.

They appear to be equal right? Not entirely. You have to consider the time it takes each transmission to transition from (rpm after a shift) to (top speed in that gear). At 65 mph, the gsr transmission is just nearing the shift point in 2nd, while the b16 transmission is already in the bottom of the powerband in 3rd.

So even though all transmissions are landing in a similar part of the powerband after shifts, the shorter transmissions (ITR, b16) are moving through that powerband, toward the shift point and the next gear, more quickly.

That's my take on the situation. Hopefully that helps clarify why they appear so similar in your calculations, yet are actually quite different.

If I'm way off base with anything I said, somebody please set me straight.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by OBD1Kenobe &raquo;</TD></TR><TR><TD CLASS="quote">
Example (made up numbers):

Let's say a b16 hydro from 1st to 2nd is 40/60 or .6667,
and a gsr is 45/67.5, also .6667.

They appear to be equal right? Not entirely. You have to consider the time it takes each transmission to transition from (rpm after a shift) to (top speed in that gear). At 65 mph, the gsr transmission is just nearing the shift point in 2nd, while the b16 transmission is already in the bottom of the powerband in 3rd.

So even though all transmissions are landing in a similar part of the powerband after shifts, the shorter transmissions (ITR, b16) are moving through that powerband, toward the shift point and the next gear, more quickly.

That's my take on the situation. Hopefully that helps clarify why they appear so similar in your calculations, yet are actually quite different.
</TD></TR></TABLE>
well, you can't move through the powerband faster than the next guy if you both landed at the same engine speed in the next gear unless one car is going slower than the other in the next gear, in which case that car will have less wind resistance and more of its power goes into accelerating the vehicle and less goes into overcoming aerodynamic drag.

basically, it all comes back to my #3 possiblity, which i find very interesting. if this really is true, it means that aerodynamics OWNS us all. so, instead of getting a shorter tranny, what we really need is underbody diffusers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95lstegman &raquo;</TD></TR><TR><TD CLASS="quote">
well, you can't move through the powerband faster than the next guy if you both landed at the same engine speed in the next gear unless one car is going slower than the other in the next gear, in which case that car will have less wind resistance and more of its power goes into accelerating the vehicle and less goes into overcoming aerodynamic drag.

basically, it all comes back to my #3 possiblity, which i find very interesting. if this really is true, it means that aerodynamics OWNS us all. so, instead of getting a shorter tranny, what we really need is underbody diffusers.</TD></TR></TABLE>

True, aerodynamics play a big part and no one thinks about it. Also though gears do play an important factor, so does engine stroke, weight of internal parts(rotating assembly), wheel diameter and weight, and vehicle weight! Im sure there are a few others that I missed, but these will all play a part in how an enine will flythrough the rpms!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95lstegman &raquo;</TD></TR><TR><TD CLASS="quote">well, you can't move through the powerband faster than the next guy if you both landed at the same engine speed in the next gear</TD></TR></TABLE>

Sure you can. The gears are different. Shorter gearing makes it possible.

Imagine two tegs at a strip - identical in every way execpt one has a gsr transmission, the other has a b16 transmission. Now, are you trying to tell me the guy driving the car with the b16 transmission wouldn't have to shift sooner???

Of course he would. Because of the b16 transmission's shorter gearing, the engine in that car would arrive at the shift point (8500rpm in your example) sooner. That should be obvious.

Q: How did it arrive at the shift point sooner?
A: The shorter gearing moved the engine through the powerband faster.

If that wasn't the case, you could get through the powerband to the shift point just as quickly in 4th as you could in 1st...

 

[QUOTE=95lstegman]

upshift #, followed by RPM in next gear
GSR
1-2, 4999rpm in second
2-3, 6076rpm in third
3-4, 6467rpm in fourth
4-5, 6470rpm in fifth

'98-'00 JDM ITR
1-2, 5540rpm in second
2-3, 5895rpm in third
3-4, 6027rpm in fourth
4-5, 6464rpm in fifth

Hydro B16
1-2, 5533rpm in second
2-3, 5888rpm in third
3-4, 6453rpm in fourth
4-5, 6510rpm in fifth

1)anybody spot a mistake?
2)is this a revolution in which gears are better
QUOTE]

Check out this site, i am pretty sure it is as accurate as you can get, when i had my GSR tranny and shifted at 8000 RPM, i landed at like 6000 RPM, not 5000.
just my 2 cents

http://www.autocrossing.com/cgi-bin/gearcalc.cgi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by OBD1Kenobe &raquo;</TD></TR><TR><TD CLASS="quote">Now, are you trying to tell me the guy driving the car with the b16 transmission wouldn't have to shift sooner???</TD></TR></TABLE>
i am saying that yes it would have to shift sooner. the B16-geared car would be faster ONLY because when that car shifts a given upshift, it is going slower than the other car during the same upshift, and since it it going slower, it will have less air and rolling resistance during the shift which will slow the car during the shift, and this is why the B16-geared car is faster. not because of anything directly related to the gears.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4DooRGiSzer &raquo;</TD></TR><TR><TD CLASS="quote">
Check out this site, i am pretty sure it is as accurate as you can get, when i had my GSR tranny and shifted at 8000 RPM, i landed at like 6000 RPM, not 5000.
just my 2 cents
http://www.autocrossing.com/cgi-bin/gearcalc.cgi</TD></TR></TABLE>
1-2 shift is most cars is much longer than the other gears. reason being that gear 1 is for getting you moving, it's not a driving gear. the other gears are closer to keep the engine in the powerband, if you prefer that way of saying it, or to keep wind and rolling resistances to a minimum during shifts if you like my method here. these calculations are also imperfect, with at least 2 important variables left out, so if you could lend a hand and produce a formula to include one or more new variables it would be appreciated.

 

After looking at that calculator, I wonder if I should switch out my GSR tranny 2nd gear for a B16 second gear? B/C 2nd on a GSR sucks just as bad as an LS eventhough the GSR has a 4.40 FD. 3rd and 4th kick *** though!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95lstegman &raquo;</TD></TR><TR><TD CLASS="quote">instead of getting a shorter tranny, what we really need is underbody diffusers.</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95lstegman &raquo;</TD></TR><TR><TD CLASS="quote">the B16-geared car would be faster ONLY because...it is going slower than the other car during the same upshift, and...it will have less air and rolling resistance during the shift...not because of anything directly related to the gears.</TD></TR></TABLE>

<FONT COLOR="blue">For clarification, let's make sure we are both speaking the same language and draw a distinction between speed (velocity) and quickness (time).</FONT>

I understand where your line of thinking is coming from, but to think that aerodynamics has more effect on acceleration than gearing does, is erroneous. Unless you are talking about top speed runs at the salt flats, you are giving entirely too much weight to aerodynamics. Even in the case of a top speed run, it is gearing that determines how quickly the vehicle reaches a speed where aerodynamics begin to play a significant role.

As a gross generalization, there are two ways to gear for "performance" in a car:
1. Long gearing for top speed. Here is where aerodynamics becomes crucial. At very high speed, yes, aerodynamics owns.
2. Short gearing for quick acceleration. When buzzing around town, or even at the strip, gearing is the crucial factor.

I'm not sure I can make my point any clearer, and I fear I may start repeating myself.

Do you really believe that the velocity-based drag on a vehicle, for the split second that the engine and transmission are disengaged during shifts, would have more influence on the outcome of a race than gearing would?

If you are still holding on to this idea, I don't think I'll be able to convince you otherwise. To that end, I will not try. I feel I've made my point, and I'm certainly not going to e-argue about the issue. It's good that you took the time to crunch some numbers and attempted to draw conclusions from them, but it appears you are trying "to rewrite the book" based on ill-formed ideas and illogical assumptions.



Respect and adios.

 

thank you. i was trying to find somebody who would explain why these numbers do not agree with actual acceleration tests. i don't feel that you have explained the reason however.

as a side note, aerodynamic resistance combined with rolling resistance is a huge factor. on the interstate, it consumes about 1/4 of our cars' horsepower. for a 200hp integra, that's 50hp. that's a lot to sweat about.

 

I have a formula to calculate loss of horsepower due to aerodynamic drag and the drag coefficient for most cars. I will post it up when I get home!

usually I do not notice a huge loss until around 85-100 mph! My car at 60 mph only has a 9-11 hp loss due to aero drag.

 

HP loss due to Aerodynamic Drag is approximately
equal to:

Cd * A * (V3) / 150,000

Cd = drag Coefficient
A = frontal area in sq. ft.
V = Velocity (speed) in MPH

Drag coefficients and Area can be found here:

http://www.teknett.com/pwp/drmayf/tbls.htm

Enjoy!

 

thanks, i've calculated mine before, although i don't like the frontal area method. in any case, i think i found mine at 55 to be 11hp. it was a while ago, stock ride height, ITR lip and wing, decent tires, no splitter or underbody spoilers.

 

Alright look at it this way:

Two identical engines, one with a B16 tranny, one with an LS tranny. Both take off at the drag strip. The one with the B16 tranny will accelerate faster due to the fact that it takes less power to turn the shorter B16 gear (though physically a taller gear) to a faster speed than the longer (though physically shorter) LS gear. Assuming that each driver takes precisely the same amount of time to shift, then by the end of the race, it's possible for the car with the B16 tranny to have gained half a second (or more or less depending upon the setup) over the LS equipped car due to this principle.

Put it another way, if the gearing in one tranny is 20% shorter than in another, then the motor equipped with the close ratio tranny will have to work 80% as hard as the other motor in order to achieve the same acceleration results as the car equipped with the longer ratio tranny.

Yet another illustration: Do you accelerate faster in 2nd gear or 5th gear? Of course you accelerate faster in 2nd gear because the motor has to work much harder to accelerate in 5th gear. Same thing when you're dealing with say a B16 first gear and a GSR first gear, the B16 first gear will accelerate faster because it requires more power to turn the GSR first gear.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">After looking at that calculator, I wonder if I should switch out my GSR tranny 2nd gear for a B16 second gear? B/C 2nd on a GSR sucks just as bad as an LS eventhough the GSR has a 4.40 FD. 3rd and 4th kick *** though!</TD></TR></TABLE>

Should I do this or would it not be worth it and possibly mess up my 2ndto 3rd transition.

 

really, don't bother. either get B16 2-4 gears or leave it alone. mixing and matching gears is for somebody who really has a problem with their gears. if you're staying in powerband, get a set like that. Honda matches their ratios pretty well to keep the engine in the same powerband for each shift. the LS doesn't do this quite so well, but it keeps me in the powerband. plus, i have a 4.40 final drive in mine.

 

Now i need a b16 tranny.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95lstegman &raquo;</TD></TR><TR><TD CLASS="quote">really, don't bother. either get B16 2-4 gears or leave it alone. mixing and matching gears is for somebody who really has a problem with their gears. if you're staying in powerband, get a set like that. Honda matches their ratios pretty well to keep the engine in the same powerband for each shift. the LS doesn't do this quite so well, but it keeps me in the powerband. plus, i have a 4.40 final drive in mine.</TD></TR></TABLE>

Yeah but when I shift from 1st @ 8000 rpms into second, im at 4800, and fallen out of my powerband and I feel such a lag, but 3rd and 4th are so strong that I am happy. I may get a B16 tranny again but I do not want to switch LSD's over when I can just switch over 2nd gear. I think the 2nd gear would suit me better! 2nd gear for the GSR is the same as the LS, which is the gear I hated most but I always loved the 2nd gear in my B16 tranny.