I don't think it means this

What does it do? drop 3rd further into 2nd and make 3rd the looooooooooooong gear?

If I can rebuild a motor can I get my 3rd flipped?

Thanks

I think what you're refering to is a flipped fifth in third gear. This is a somewhat common change that gives a shorter third gear, especially on cars with a longer fifth gear. So, some people get a new 5th gear (like an H for a V8 car), drop the flipped 5th down to 3rd and toss the 3rd gear.

you drop 5th into third and flip the gears...

makes a short third gear... then you need a shorter 4th to make that shift pleasant, otherwise youll be below powerband in fourth....

QUOTE (Aaron Cox @ Sep 27 2005, 04:47 PM)

you drop 5th into third and flip the gears... makes a short third gear... then you need a shorter 4th to make that shift pleasant, otherwise youll be below powerband in fourth....

What forth would you recommend and where do I get it because I have that issue right now. 3rd - 4th bogs.

QUOTE (olav @ Sep 27 2005, 06:07 PM)

QUOTE (Aaron Cox @ Sep 27 2005, 04:47 PM) you drop 5th into third and flip the gears... makes a short third gear... then you need a shorter 4th to make that shift pleasant, otherwise youll be below powerband in fourth.... What forth would you recommend and where do I get it because I have that issue right now. 3rd - 4th bogs.

original SIX trans?

A GA N V Z (stock six)
A F N V ZD (stock 4)

how short of a 3rd/4th/5th would you like?

some bitchin setups out there (racing and all)

QUOTE (Aaron Cox @ Sep 27 2005, 09:09 PM)

A GA N V Z (stock six)

A GA N V ZA

QUOTE (ArtechnikA @ Sep 27 2005, 06:25 PM)

QUOTE (Aaron Cox @ Sep 27 2005, 09:09 PM) A GA N V Z (stock six) A GA N V ZA

correct. ZA. Z is even shorter than ZA
thanks rich

QUOTE (qa1142 @ Sep 27 2005, 04:26 PM)

What does it do? drop 3rd further into 2nd and make 3rd the looooooooooooong gear?

What you do is: You take a 3rd gear set from a spare transmission--hopefully a low one, like an "H" gear. You remove 5th gear from your transmission, and instead you put the 3rd gear gears on in the place of 5th. However, you swap which shaft the gears ride on--so what would have been the drive gear becomes the driven gear, and what would have been the driven gear becomes the drive gear.

This has the effect of inverting the gear ratio for that gear. So the "H" 3rd gear, if I read the chart correctly, is 19:32, or a 1.684 ratio. Instead, you wind up with a 32:19 gear, which is a 0.584 ratio, much taller than the tallest regular 5th gear (about 0.7 ratio).

Does that make sense?

Note that you can only "flip" 3rd, 4th, and 5th gears. 1st is unique, and 2nd is a part of the mainshaft so it cannot be changed. (Not unless you get the $$$$ 904 mainshaft, but that's a discussion for another day and another person's wallet.)

--DD

again - dave is better at explaining than anyone

Dave
What did Aaron just say?

hey dave; can you do the conversion to the standard gear ratio's from the porsche code, idon't get they're gearing numbers.

i have a 1975 914 1.8

A 1 11 : 34 (3.091)
F 2 18 : 34 (1.889)
N 3,4,5 23 : 29 (1.261)
V 4,5 27 : 25 (0.926)
ZD 4,5 31 : 22 (0.710)

and the ring and pinion is a 7 something to 1?

QUOTE (messix @ Sep 27 2005, 08:05 PM)

and the ring and pinion is a 7 something to 1?

7:31

so 7:31 x .710 = 5.19 is the final drive ratio? and my tires are 22" tall, i'm suprized i'm not turning 9,000 rpm at 70 mph.

QUOTE (messix @ Sep 27 2005, 08:32 PM)

so 7:31 x .710 = 5.19 is the final drive ratio? and my tires are 22" tall, i'm suprized i'm not turning 9,000 rpm at 70 mph.

no way you have 22" tires.....

I think there is a lot of confusion here.

For Autocrossing, you can create a longer 3rd, and shorter 5th by switching and reversing 3rd and 5th, from the same transmission.

A "Standard" 4 cyl:

A 3.091:1
F 1.889:1
N 1.261:1
V 0.9259:1
ZD 0.8097:1

Now flip and reverse 3rd and 5th

A 3.091:1
F 1.889:1
(ZD) 1.4090:1
V 0.9259:1
(N) 0.7930:1

3rd, 4th and 5th gears are now much closer in ratio.

Is this good? If you have an engine with a narrow high power band, it may help. If you have an engine with a wide power band? Nope.

QUOTE (Aaron Cox @ Sep 27 2005, 08:38 PM)

QUOTE (messix @ Sep 27 2005, 08:32 PM) so 7:31 x .710 = 5.19 is the final drive ratio? and my tires are 22" tall, i'm suprized i'm not turning 9,000 rpm at 70 mph. no way you have 22" tires.....

just measured them.... 21.5" tall 195/50 15" khumos

QUOTE (messix @ Sep 27 2005, 09:13 PM)

QUOTE (Aaron Cox @ Sep 27 2005, 08:38 PM) QUOTE (messix @ Sep 27 2005, 08:32 PM) so 7:31 x .710 = 5.19 is the final drive ratio? and my tires are 22" tall, i'm suprized i'm not turning 9,000 rpm at 70 mph. no way you have 22" tires..... just measured them.... 21.5" tall 195/50 15" khumos

this says 22.67"

tire size calc

i measure loaded diameter. it does have an effect on tire rotaion per mile

not all tires match the calc. like ummm hoosiers

A .710 gear would be overdriven by 29%. For every one rpm, the gear ration feeds 1.29 rpm to the pinion.
4.4/1.29= 3.43 effective ratio.

some how these ratios don't add up

i used this gearing calc. to try your numbers and if i have that final drive ratio of 5.19/1 my rpm at 70 5,548rpm?

http://www.novak-adapt.com/knowledge/gearing.htm

try this out

i think my rear gear ratio is closer to 4.10/1

QUOTE (messix @ Sep 27 2005, 09:45 PM)

some how these ratios don't add up i used this gearing calc. to try your numbers and if i have that final drive ratio of 5.19/1 my rpm at 70 5,548rpm? http://www.novak-adapt.com/knowledge/gearing.htm try this out

its off by a few hundred rpm.....

A .710 gear would be overdriven by 29%. For every one rpm, the gear ratio feeds 1.29 rpm to the pinion.
Actually it's 4.42:1.29 or a 3.43 effective ratio.

i thought the ring an pinion was 7.31/1?

so 7.31x .71= 5.19/1

James and all...
I've heard of a flipped ZD called a:

K/L

because the ratio comes out between what a K gear is and an L gear is.

brant

QUOTE (messix @ Sep 27 2005, 08:55 PM)

i thought the ring an pinion was 7.31/1? so 7.31x .71= 5.19/1

7 teeth on the pinion, 31 on the ring gear=4.42 & change

QUOTE (J P Stein @ Sep 27 2005, 10:03 PM)

QUOTE (messix @ Sep 27 2005, 08:55 PM) i thought the ring an pinion was 7.31/1? so 7.31x .71= 5.19/1 7 teeth on the pinion, 31 on the ring gear=4.42 & change

JP - look at my chart. its a few hundred rpm shy of where it really is....

why didn't you guys say that .....jeeeezzzzz you got all frustrated

QUOTE (Aaron Cox @ Sep 27 2005, 10:05 PM)

QUOTE (J P Stein @ Sep 27 2005, 10:03 PM) QUOTE (messix @ Sep 27 2005, 08:55 PM) i thought the ring an pinion was 7.31/1? so 7.31x .71= 5.19/1 7 teeth on the pinion, 31 on the ring gear=4.42 & change JP - look at my chart. its a few hundred rpm shy of where it really is....

err.... im wrong. my excel sheet says 78 mph at 3500 for me.....

so i did my calcs right....

thanx Aaron

QUOTE (messix @ Sep 27 2005, 10:10 PM)

thanx Aaron

im just another Zit on the Butt of life.....

So is it worth it to do this on a mostly stock 2.0 used for general driving?

QUOTE (ws91420 @ Sep 27 2005, 10:14 PM)

So is it worth it to do this on a mostly stock 2.0 used for general driving?

nope.

unless you want 0-60's like a freight train and a new fourth gear.... Oh... and a larger gap between 4th and 5th

QUOTE (Aaron Cox @ Sep 27 2005, 09:05 PM)

JP - look at my chart. its a few hundred rpm shy of where it really is....

EH???
Sorry, but I don't understand. "it's (ughknown).blabla...of where it really is..." (ughknown also) what's the meaning of "is"

Can we try again?
While we're at it, what chart? You talkin' about that calc sheet?

OH, you got all fingered out?
Slow typin' has done me in before, but I'll post this to show ya just how confused you had me

QUOTE (J P Stein @ Sep 28 2005, 05:45 PM)

QUOTE (Aaron Cox @ Sep 27 2005, 09:05 PM) JP - look at my chart. its a few hundred rpm shy of where it really is.... EH??? Sorry, but I don't understand. "it's (ughknown).blabla...of where it really is..." (ughknown also) what's the meaning of "is" Can we try again? While we're at it, what chart? You talkin' about that calc sheet? OH, you got all fingered out? Slow typin' has done me in before, but I'll post this to show ya just how confused you had me

yep...massa JP, all figured out.

but it WAS calculated, and WAS a few hunderd RPM short of where it REALLY is in REALITY

I'm so confused....................
Bob

QUOTE (Aaron Cox @ Sep 28 2005, 04:52 PM)

but it WAS calculated, and WAS a few hunderd RPM short of where it REALLY is in REALITY

Sure, that makes perfect sense, Bill....ah Aaron.
.

So if I understand this right I can make an overdrive fifth gear by taking a spare third gear and place it in place of fifth, but backwards???

Would this be a good choice to get my rpms down on the freeway in a Buick V6 powered car? On the freeway the V6 is much too buzzy for my likes, an over drive fifth would be great, are there other options (for the stock 914 tranny) of gear ratios that would be useful for a V6 application, (especially if they are stock gears, as i have a spare tranny to select parts from)

Whats possible???

QUOTE (MattR @ Sep 27 2005, 05:46 PM)

I think what you're refering to is a flipped fifth in third gear.  This is a somewhat common change that gives a shorter third gear, especially on cars with a longer fifth gear.  So, some people get a new 5th gear (like an H for a V8 car), drop the flipped 5th down to 3rd and toss the 3rd gear.

Matt's right on, on that one. With that kind of differential ratios a 6 or V8 likes that over driven 5th gear.

I've got the H in the 5th place. 1st is removed (the weakest gear) (too low for high torque engines anyway) and i'd be comfortable cruising any distance. 355 cid V8.

Then when I finally race AX I will start in second and only get to third which will be a quick trip. =-)))

Doods with big lathes can just machine the mainshafts.. huh?



Miles

QUOTE (redshift @ Sep 29 2005, 12:37 AM)

Doods with big lathes can just machine the mainshafts.. huh? Miles

nah, you just go buy a 904 main shaft from Otto's for a removeable 2nd gear. But who needs that!

I am switching my gears around to get a better 2-3-4 ratio and leaving 5th a ZD for freeway drivin.

QUOTE (qa1142 @ Sep 27 2005, 04:26 PM)

I don't think it means this What does it do? drop 3rd further into 2nd and make 3rd the looooooooooooong gear? If I can rebuild a motor can I get my 3rd flipped? Thanks

If you want to stay in CS check the rules, I think this wouldn't change your class.

Check out this chart.

My feeling is that the flipped 5th into 3rd is ok for a only AX box but its a little bit short for street. Withit thou you can drive around the street just in 3rd with tons of power as it right in the torque band

Long rpm drop when you shift to 4th thou......

so locate a shorter 4th and do the swap at the same time.

chart