At least the few folks I've talked to are happy to finish the 1/4 in 4th. My question is why not embrace the mechanical advantages of an additional gear or is the risk of an extra shift just not worth it?

Clearly, you'd need the correct gear set all the way through the box, so you run out the top wound tight in 5th, not 4th. Runs about $800 as near as I can tell. And I spend 1/2 of my run in 4th, just ******* it out (relatively speaking).

a shift (for me) seems to take about .2-.25 seconds, and I'm in 4th for 4-5 seconds. one extra shift for a gain in mechanical advantage (all the way through the run) seems like a decent trade off to me, especially on top.

Don't know, maybe it's already common practice... I'm the only Honda guy in a 300 mile radius, so I don't see what others are doing, first hand.

Just curious.

 

The handcuff for one, and the fact that that extra gear change does add so much time to the run. Especially on boosted cars, once strain gaging is more common and trannies become designed better I can't see why a 5th couldn't be put into play but I like my 3 gear changes, less to mess up

To not 'dog out' in 4th, that's simple. Make more power!

 

5th is a granny shift to it take some practice ive had to do it a few times its sucks but after 3 trys i nailed it! but its not like 5th is a noraml shift like 2nd to 3rd you really have to push to the right to speed shift for all motor car!

 

I would rather have a 3 spd.

 

better have some torque for that 3 speed.

we aint trapping high enough mph for a 5 speed. wasting to much time shifting

 

Do a normal run then a run shifting to 5th. Compare the data for both runs and you'll see how bad shifting to 5th hurts you. (assuming you have some kind of data acquisition)

 

I don't know that I completely believe that. Anybody doing high 9's to low 10's has made 3 shifts to get to 4th and that happens in the first 5 seconds. You've got a lot of time on your hands riding out 4th in a 10 second pass. That's a pretty big loss of mechanical advantage at a time when you're fighting MASSIVE aerodynamic drag. (how much horsepower does it take to get a wide nose Civic to hold 145mph?)

Mind you, as it was mentioned, "just get more horsepower".... In lieu of that, I'm of the opinion that an $800 gear set is pretty cheap in the big picture. and something fun to try. I'd rather ride the limiter for a touch on the top end, than in 1-2-3 where getting to speed is more critical.

The question is, even if the 4-5 shift is slow, say .4 seconds (where the car has stopped accelerating at let's say 110-115mph). could you gain more than .4 seconds back, over the course of the next 5 seconds through increased mechanical advantage. And the mechanical advantage of much less RPM drop per shift.

Silly chart I made. I'm of the opinion that you wouldn't mph any higher, you'd just get to your best mph, quicker. if you're running 10.0@146, I'm thinking you might run 9.7@146.

I truly don't know. Just doing some bench racing with ya'll.

 

Car has to be re-geared to do it. and the data would look like the above image.

If going from 3 speed is seen as a disadvantage because it's ineffective gearing, why do you feel 5 wouldn't net the same improvement that 3 is said to ruin (compared to 4)? The time you're giving up on the shift is .25 seconds. the mechanical advantage of more favorable gearing is seen through the whole pass of say 10 seconds. you're potentially giving up .25 to gain improvement continuously over 10 seconds. the real question is whether or not the mechanical advantage can overcome the .25 over that period. To be a real pessimist one might say that perhaps only the last 5 seconds would show improvement. Even then, could you overcome the .25 seconds in 5 seconds? I say it will.

I like this kind of bench racing.

 

there is a old video game for pc called IHRA drag racing, by bethesda soft, it allowed you to build every aspect of a chassis and drive line, i used to build all kinds of trannies and gear ratios, from 1 speed to 8 speed , and as this guy states the more gears typically the better et at the same mph. i know it was only a game but it was pretty good at simulation.

 

Let me tell you a little story, in my young days. LOL

I had this sand rail with a VW 1835cc motor, once a year I would go to the beach and take on the heavy hitter, it was this sand hill called competition hill. The guys I would go against would have 2180 cc or turbo engine, and I WOULD get hammered every time. So I said to myself, how can I get back at them, go to a bigger motor or wait turbo YES that would solve all my problems, Right? Wrong, and this is what I did. I changed out my first gear to a low granny gear you know like a 1940 pick up truck, and second gear was like in between first and second. This way I would only have the tranny in second gear and that would be one less shift I would have to make. Well it worked and I never got beat again with my 1835 cc motor.

I think if you add a gear it's going to hurt you, especially in drag racing. Maybe not with a automatic because it's going to be a smoother transition, but who knows.

Best of luck,

SlicksMH

 

I don't have a data logger, but I've tried just about every gearing setup possible for the D series. I'm very low power NA. Hitting 5th gear caused me to run slower every time. This was with a 1.000 5th gear. I ran faster by winding it out past peak power in 4th (1.259).

If running a shorter gear set and hitting 5th was faster, the fast guys would be doing it (Tony, Miller, Cort, Cunha, Steve, Jake, Lisa, etc).

If you feel 4th is too long, drop down to a smaller slick size if you can manage the traction.

 

I've always loved Erick's 5th gear performance in this video:

http://www.youtube.com/watch?v=luDgWR6IgYg

 

I remember that game, and I did the exact same thing....haha

 

oh man stormer haha good idea though

 

If you could stay in 4th and finish the wrong, the gearing is not acceptable to make it work. You need to be done with 4th and have to grab 5th and then run 5th out on the limiter to see the mechanical advantage work in your favor.

The fast guys have 1000whp... horsepower solves a lot of problems with gearing. The rest of us with beer budgets need to look around for ideas.

 

You may find ideas. But what you need is money for someone to build you the ideal tranny. Hey the guy's in F1 have there trannys optimized, but I'm guessing most of us don't have that budget. So you/we have to sork with what's out there.

That's why most prople do whatever the fast guy's, miller and tony do.

Unless you have the cash, move onto something else that you can afford that will help you.

Sorry if I put a damper on your thought process. Have a good day.

 

No problem , just bench racing. no damper on this party!

I'm confident I could swing a $1000 transmission upgrade. especially if it got me say a 9.6-9.8 for my efforts. It's that or I have to find another 50-100whp minimum. Which one is cheaper? Watch the video posted above. Look closely at the datalog that I ran a 10.0 with and the modified example with 5th added and the gearing moved around.

Mfactory makes everything necessary, nothing custom required. so that should also point to the fact that it's a decent idea, at least in theory.

Just compare these 2 transmissions, it's do-able.
http://www.teammfactory.com/gearcalc...ission+1+%26+2

I will say this. I think it would probably NOT make the best 1/8 mile transmission if you're running 6.5-6.8, as it would add a shift to 4th at the end. not as versatile in that respect. UNLESS, you're crossing the line at say 10,200 or more. Then, maybe.

 

The MFactory close gear sets would be useless for a decent power turbo setup, and they're the standard gears, not the PRO gears.

There is no advantage to running in 5th IMO. Smaller gear to break more easily, another shift (long shift at that) dampening the momentum of the car. Unless you were to run a different (not OEM) trans you're not going to make the 4-5 shift fast enough to not upset the car. If you could what is the point? 4th is long enough to finish out in and short enough to not bog down. You're not going to have any more power available shifting to 5th and if you have the 4spd setup properly you're not going to gain back the time/speed lost from adding a 4th shift.

Let me ask you, what is your current trans setup now?

 

I play that game everyday on my ps2. Set NEDW as my hometrack and everything, so far i got the fuelie 2 runing 5.4 @ 280mph, like .9xx 60 foot. Love that game.

 

the most important part of your quarter mile et is how quick you can get the car moving. the closer the gears the more possibe acceleration you will have. so you are telling me that a car with a 3.07 2.105 1.458 1.107 will accelerate better than a 3.07 2.105 1.695 1.384 1.13? not true. perfect example agian is this video here. http://www.youtube.com/watch?v=luDgWR6IgYg

the only advantage to 4 gears is a high hp turbo application.

 

I think it's a good consideration for all motor cars. The longer you can keep the motor at the top of it's power curve (high rpm generally), the better. Another gear would allow that. For what it's worth, pro stockers like it

Oh, and it's hard to argue with pullin 5th after watching the video of Erick

 

X2! but all pro stocks run the 5spd...

 

but all pro stocks run the 5spd...[/quote]


that's what i meant

 

Wait a second... Just how old is this story? Didn't you sit behind Jesus in 1st grade?

 

You can't assume that shifting to 5th costs you a lot of ET, if any at all. At the point you are going to 5th you are at high speed and covering so much ground that the time spent shifting that gear does not have the same effect as it does in gears at lower speed. If it takes you .3 to shift...what do you lose in ET at xxx mph?

I have tried both in my EVO, running 4th out to 8500 or running my normal rpm range and going to 5th at 7800 and the car ran better going to 5th. There are so many variables.

The way I look at it...it is one more gear to miss, one more gear to break. It might be different if we were working with a Liberty pro stock tranny or something.