2.73 Ring and Pinion in G28/11
08-18-2015, 12:27 PM
#47
Rennlist Member
One time tax when it's sold, it's a sliding scale, and the tax rates have changed a bit since '85. Today, a combined city/highway MPG of just under 22.5 is taxed at $1,000 and under 12.5 MPG is $7,700. Trucks and SUVs are exempt for some stupid reason.
08-18-2015, 12:44 PM
#48
Drifting
Thread Starter
If I can find a G28.10 Ring and Pinion or a complete G28.10 Transmission at a reasonable price in the near future, I will buy it and try it.
If I don't find one soon, I will button the system up with the LSD + 2.20 stock ratio and drive that, but keep my eye out for g28.10 hardware to buy for future use.
I am not going to follow up on trying to fit a non g28.10 R&P into a G28.11 box.
08-18-2015, 12:49 PM
#49
Drifting
Thread Starter
You have the distinct advantage of being able to replace syncho's in your sleep. And if I lived closer to your shop, I might shift my priorities, knowing that when the syncho's wore out, you could rebuild quickly and correctly.
08-18-2015, 01:52 PM
#50
Rennlist Member
did you not read my last post to you ?? its speed ranges. ive said it time and time again. and by your post here, it seems you miss that point entirely.
a 2.2 is good for some tracks and HP ranges (AND DRIVER ABILITY as thats a factor too) and a 2.75 is good for others too.
again, it DEPENDS on the speed ranges used and the time spent at those speed ranges
08-18-2015, 02:09 PM
#51
Rennlist Member
gear spacing is near the same for all gear boxes... thats key
in speeds above 1st gear (ingnoring launch in drag situations)
if im goinig to run my car at 45mph, you with a G05 will be in 2nd (lugging) and ill be in 1st , ready to party! you see, its trade offs along the entire speed range of the car. (untlil 5th and we all know thats a overdrive for the 2.2 boxes and thats a given... but who needs non-luggy perfornmance in 5th, when 4th goes to 150mph!
) What Kibort is trying to make into a "Law" only applies to closed course racing, where one is already moving....and there is ample torque to be able to only use a couple/three gears (like with a V8 engine.) I completely understand what he is saying regarding his scenario. However, his argument is just that....arguing for the sake of arguing, for this thread's topic.
Once a "broad" torque range starts to go away and an engine makes higher rpm horsepower, instead of midrange torque, shorter/closer ratio gears become mandatory. If you own a 906, with a very limited torque range...Kibort's "my ideas fit every scenario" are completely wrong. You better have short enough gears to keep the engine in the power range, or you are going to be terribly slow around a closed course! Simply stated, you need the short gears/closer ratios to keep the engine in the effective power range. You leave the "highest" gear completely unused and the next one down only effective through half of the rpm range....and you are going to be very slow around a closed course.
Take this idea "one step further" and think about a Formula One engine or an Indy car engine....which make even less torque and more high rpm horsepower. They figure out their top speed possible on a given course and then gear their tallest gear to be at the peak horsepower (which is very close to redline.) All of the other ratios are calculated backwards, from that gear! There's no way they would gear their cars to not even use the top gear, like Kibort does at Laguna....that would be very slow "way" around any race course.
And, of course, as soon as one leaves the "closed course" racing situation, everything changes. If you are doing a "standing start slalom" course (where speeds very rarely get above 75mph)...a very "tall" ratio gearbox (like the G28/11), is most likely going to be a disadvantage to a "shorter" gear ratio gearbox (like the G28/05 or the G28/10.)
Street driving is almost always more fun, with "shorter" gear ratios. Almost all cars will accelerate quicker, from a standing stop, with shorter gear ratios.
Porsche didn't built the G28/10, for Europe, because they ordered the incorrect ring and pinions and had to use them up....it was intentional! Most Europeans would have never purchased the "slug" of a gear ratio that the US cars had!
Once a "broad" torque range starts to go away and an engine makes higher rpm horsepower, instead of midrange torque, shorter/closer ratio gears become mandatory. If you own a 906, with a very limited torque range...Kibort's "my ideas fit every scenario" are completely wrong. You better have short enough gears to keep the engine in the power range, or you are going to be terribly slow around a closed course! Simply stated, you need the short gears/closer ratios to keep the engine in the effective power range. You leave the "highest" gear completely unused and the next one down only effective through half of the rpm range....and you are going to be very slow around a closed course.
Take this idea "one step further" and think about a Formula One engine or an Indy car engine....which make even less torque and more high rpm horsepower. They figure out their top speed possible on a given course and then gear their tallest gear to be at the peak horsepower (which is very close to redline.) All of the other ratios are calculated backwards, from that gear! There's no way they would gear their cars to not even use the top gear, like Kibort does at Laguna....that would be very slow "way" around any race course.
And, of course, as soon as one leaves the "closed course" racing situation, everything changes. If you are doing a "standing start slalom" course (where speeds very rarely get above 75mph)...a very "tall" ratio gearbox (like the G28/11), is most likely going to be a disadvantage to a "shorter" gear ratio gearbox (like the G28/05 or the G28/10.)
Street driving is almost always more fun, with "shorter" gear ratios. Almost all cars will accelerate quicker, from a standing stop, with shorter gear ratios.
Porsche didn't built the G28/10, for Europe, because they ordered the incorrect ring and pinions and had to use them up....it was intentional! Most Europeans would have never purchased the "slug" of a gear ratio that the US cars had!
so, you want to optimize hp over any speed range or ranges. the short or tall gears will have trade offs ,, just as you have with the 2.2 vs the 2.75/2.72 gear boxes and this is the same for any car, v8 or not. that 4 banger that peaks at 8k and has no torque but 200hp, will want to have its driver operate it at near max HP as much as possible. depending on the speed the driver can operate the car at , on a course, that will determine what gears he will require. it might be the tall version or the short version. BECAUSE there is a speed range for operating a car on the track for the straights, turns and exits. tall or short gears is NO guarantee that it will work best. it depends on other factors that are very obvious if you understand the concepts.
the "broad torque" range has NOTHING to do with it.. most low torque engines have very flat torque curves.... its the peakiness of the hp THAT is trying to be utilized . close ratios do this .. short or tall gears are desired depending on the speed ranges.
as far as formula one cars and their gearing.. .they are doing exactly what i am doing. i dont care what you call the gear. .("4th , or 5th) as long as i get a gear that peaks out at near redline on the most critical straight. this is the kind of race craft , behind the scenes that wins races. ..... I cant help it that i cant use 5th gear , since the gear spacing is fixed, it doesnt mattter. if i have 3 gears to work with, then i want that last gear to be at near redline on the longest straight, or make sure that the middle gear is used to redline for most of the course. there are some trade offs..... its all about maximizing HP-seconds. you should know this. to your AutoX point , again, you miss the point. if your speed range is up to 75, you want the 2.2 gear box. it can have 2 gears that can redline at just under 80mph. perfect for the course and even more perfect if you can actually use 1st in some of the mid speed turns. a 2.75, might have to shift in to 3rd during a autoX straight and not be able to use 1st gear in some mid speed turns.... thats a great example......... you have to think about HP-seconds and get off your "flat torque curve" kick... that means nothing but a rising HP curve.....
It is impossible to state it any better than this! Spot on!
Of course, I'm in the minority of people which really love the pre-Borg Warner transmissions. I love the way they feel. One gets feedback from every shift. You miss a shift and stick the transmission into the wrong gear....you know it way before you let the clutch out....way before you even get the shifter all the way into gear.
The Borg Warner transmissions were made for doctor's wives to be able to drive.....transmissions for girls to be able to drive Porsches. They are like moving a joystick around on a computer game....zero feeling.
Of course, I'm in the minority of people which really love the pre-Borg Warner transmissions. I love the way they feel. One gets feedback from every shift. You miss a shift and stick the transmission into the wrong gear....you know it way before you let the clutch out....way before you even get the shifter all the way into gear.
The Borg Warner transmissions were made for doctor's wives to be able to drive.....transmissions for girls to be able to drive Porsches. They are like moving a joystick around on a computer game....zero feeling.
08-18-2015, 02:37 PM
#52
Nordschleife Master
08-18-2015, 03:17 PM
#53
Rennlist
Basic Site Sponsor
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again, you must have missed what i explained in detail here.
gear spacing is near the same for all gear boxes... thats key
in speeds above 1st gear (ingnoring launch in drag situations)
if im goinig to run my car at 45mph, you with a G05 will be in 2nd (lugging) and ill be in 1st , ready to party! you see, its trade offs along the entire speed range of the car. (untlil 5th and we all know thats a overdrive for the 2.2 boxes and thats a given... but who needs non-luggy perfornmance in 5th, when 4th goes to 150mph! )
glen.... its NOT a "formula" its an equation, derived form two identities.
Greg, you almost have the information understood, but you miss the mark considerably... especially with your example. this is not an argument to "argue" its fact and physics. yes, closer gear ratios will help with making sure any car, even the "906" but shorter gears do not. what i mean by that, is depending on the "closed course" or any kind of street use, the gear box is the HP optimizer. the closeness of gears optimize better for all speeds, and the shortness optimizes for speed ranges... its that simple.... understand??
so, you want to optimize hp over any speed range or ranges. the short or tall gears will have trade offs ,, just as you have with the 2.2 vs the 2.75/2.72 gear boxes and this is the same for any car, v8 or not. that 4 banger that peaks at 8k and has no torque but 200hp, will want to have its driver operate it at near max HP as much as possible. depending on the speed the driver can operate the car at , on a course, that will determine what gears he will require. it might be the tall version or the short version. BECAUSE there is a speed range for operating a car on the track for the straights, turns and exits. tall or short gears is NO guarantee that it will work best. it depends on other factors that are very obvious if you understand the concepts.
the "broad torque" range has NOTHING to do with it.. most low torque engines have very flat torque curves.... its the peakiness of the hp THAT is trying to be utilized . close ratios do this .. short or tall gears are desired depending on the speed ranges.
as far as formula one cars and their gearing.. .they are doing exactly what i am doing. i dont care what you call the gear. .("4th , or 5th) as long as i get a gear that peaks out at near redline on the most critical straight. this is the kind of race craft , behind the scenes that wins races. ..... I cant help it that i cant use 5th gear , since the gear spacing is fixed, it doesnt mattter. if i have 3 gears to work with, then i want that last gear to be at near redline on the longest straight, or make sure that the middle gear is used to redline for most of the course. there are some trade offs..... its all about maximizing HP-seconds. you should know this. to your AutoX point , again, you miss the point. if your speed range is up to 75, you want the 2.2 gear box. it can have 2 gears that can redline at just under 80mph. perfect for the course and even more perfect if you can actually use 1st in some of the mid speed turns. a 2.75, might have to shift in to 3rd during a autoX straight and not be able to use 1st gear in some mid speed turns.... thats a great example......... you have to think about HP-seconds and get off your "flat torque curve" kick... that means nothing but a rising HP curve.....
Mark: I don't "miss points". I'm the one making the "points" up. Everyone here understands that you are trying to eliminate shifts and just use the torque of the engine. You have a tractor with really long gears, for a race car and think that's the "hot" ticket". We all get it. But here you are (again).....trying to make a "law" from one example. Let's say that same slalom course only got to 60mph.....then you would benefit from a shorter ring and pinion, which would allow one to use all of the "shorter resulting gear". And.......almost no one really "wants" to use 1st gear.....the torque multiplication generally upsets the car too badly. Almost everyone would rather be in 2nd gear, even if it meant being slightly of the "power curve" (BTW a shorter ring and pinion would increase the rpms in 2nd gear.) In the end, gearing totally depends on the course and the torque of the engine that you are running (which was my only point). You making generic statements that a 2.20 ring and pinion is better than a 2.75 ring and pinion is absolutely silly.
i agree... but for racing, it sure makes it one less thing to think about when you are rowing the gears especially for downshifts. street driving, i have to agree with you.
gear spacing is near the same for all gear boxes... thats key
in speeds above 1st gear (ingnoring launch in drag situations)
if im goinig to run my car at 45mph, you with a G05 will be in 2nd (lugging) and ill be in 1st , ready to party! you see, its trade offs along the entire speed range of the car. (untlil 5th and we all know thats a overdrive for the 2.2 boxes and thats a given... but who needs non-luggy perfornmance in 5th, when 4th goes to 150mph!
) glen.... its NOT a "formula" its an equation, derived form two identities.
Greg, you almost have the information understood, but you miss the mark considerably... especially with your example. this is not an argument to "argue" its fact and physics. yes, closer gear ratios will help with making sure any car, even the "906" but shorter gears do not. what i mean by that, is depending on the "closed course" or any kind of street use, the gear box is the HP optimizer. the closeness of gears optimize better for all speeds, and the shortness optimizes for speed ranges... its that simple.... understand??
so, you want to optimize hp over any speed range or ranges. the short or tall gears will have trade offs ,, just as you have with the 2.2 vs the 2.75/2.72 gear boxes and this is the same for any car, v8 or not. that 4 banger that peaks at 8k and has no torque but 200hp, will want to have its driver operate it at near max HP as much as possible. depending on the speed the driver can operate the car at , on a course, that will determine what gears he will require. it might be the tall version or the short version. BECAUSE there is a speed range for operating a car on the track for the straights, turns and exits. tall or short gears is NO guarantee that it will work best. it depends on other factors that are very obvious if you understand the concepts.
the "broad torque" range has NOTHING to do with it.. most low torque engines have very flat torque curves.... its the peakiness of the hp THAT is trying to be utilized . close ratios do this .. short or tall gears are desired depending on the speed ranges.
as far as formula one cars and their gearing.. .they are doing exactly what i am doing. i dont care what you call the gear. .("4th , or 5th) as long as i get a gear that peaks out at near redline on the most critical straight. this is the kind of race craft , behind the scenes that wins races. ..... I cant help it that i cant use 5th gear , since the gear spacing is fixed, it doesnt mattter. if i have 3 gears to work with, then i want that last gear to be at near redline on the longest straight, or make sure that the middle gear is used to redline for most of the course. there are some trade offs..... its all about maximizing HP-seconds. you should know this. to your AutoX point , again, you miss the point. if your speed range is up to 75, you want the 2.2 gear box. it can have 2 gears that can redline at just under 80mph. perfect for the course and even more perfect if you can actually use 1st in some of the mid speed turns. a 2.75, might have to shift in to 3rd during a autoX straight and not be able to use 1st gear in some mid speed turns.... thats a great example......... you have to think about HP-seconds and get off your "flat torque curve" kick... that means nothing but a rising HP curve.....
Mark: I don't "miss points". I'm the one making the "points" up. Everyone here understands that you are trying to eliminate shifts and just use the torque of the engine. You have a tractor with really long gears, for a race car and think that's the "hot" ticket". We all get it. But here you are (again).....trying to make a "law" from one example. Let's say that same slalom course only got to 60mph.....then you would benefit from a shorter ring and pinion, which would allow one to use all of the "shorter resulting gear". And.......almost no one really "wants" to use 1st gear.....the torque multiplication generally upsets the car too badly. Almost everyone would rather be in 2nd gear, even if it meant being slightly of the "power curve" (BTW a shorter ring and pinion would increase the rpms in 2nd gear.) In the end, gearing totally depends on the course and the torque of the engine that you are running (which was my only point). You making generic statements that a 2.20 ring and pinion is better than a 2.75 ring and pinion is absolutely silly.
i agree... but for racing, it sure makes it one less thing to think about when you are rowing the gears especially for downshifts. street driving, i have to agree with you.
I can't even begin to estimate how many race engines I've repaired that have been "stuck" in the incorrect gear on a shift, because of the Borg Warner transmissions.....certainly dozens and dozens.
Borg Warner style transmissions allow really stupid downshifts, with virtually no feedback.
I can't ever recall this happening on vehicles with transmissions equipped with "Porsche style" synchros, because if you tried to get the transmission into 2nd gear, instead of 4th gear, on a downshift, the gearshift lever let you know, instantly, that you were making a huge mistake.
One of the really great improvements (and major "cost" reducers of Porsche racing) was the introduction of the sequential gearbox.....this single change reduced the "overrev" engine damage by hundreds of thousands of dollars in the Cup Car program, alone. And this happened simply because the Borg Warner gearbox transmissions were so easy to get into the wrong gear, whereas the sequential gearbox eliminated this problem, if the driver was smart enough to be able to count.
The reality is that he Borg Warner style transmissions were great for "easier" street driving and absolutely sucked as a race transmissions, simply because of the lack of "feel" from the gearshift lever.
I won't go any further into the other reasons that Borg Warner style transmission sucked for race use....but if you look at where the gearbox oil needs to "travel" to cool down the synchro surface, compared to the Porsche style synchro, it becomes very obvious why this style transmission "crunched" the synchros so badly, once the transmissions got hot. I had to replace entire gear sets, after almost every event, because the cone where the synchro hits on the gear would get destroyed, from heat and the resulting metal transfer, on the "professional" race cars which ran these transmissions. This NEVER happened on the transmission with Porsche style synchros.....the "hot friction surface" was on the very outside of the gear, sloshing through the cooler gear oil!
__________________
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
Last edited by GregBBRD; 08-18-2015 at 03:35 PM.
08-18-2015, 03:27 PM
#54
Rennlist Member
I NEVER come always back to road racing... Im talking ANY and all variants of speed ranges and uses. one gear box is NOT best. thats the point.
did you not read my last post to you ?? its speed ranges. ive said it time and time again. and by your post here, it seems you miss that point entirely.
a 2.2 is good for some tracks and HP ranges (AND DRIVER ABILITY as thats a factor too) and a 2.75 is good for others too.
again, it DEPENDS on the speed ranges used and the time spent at those speed ranges
did you not read my last post to you ?? its speed ranges. ive said it time and time again. and by your post here, it seems you miss that point entirely.
a 2.2 is good for some tracks and HP ranges (AND DRIVER ABILITY as thats a factor too) and a 2.75 is good for others too.
again, it DEPENDS on the speed ranges used and the time spent at those speed ranges
Can't you just accept the fact that a 928 with a lower rear ratio would be more fun to drive on the street?? Geez!
i have to ask...... why?
Glen says the differneces are noticible, but it depends on the speeds you usually travel at and when you "pass a car" do you always pass from 40-50mph or do you pass from 55 to 66, or do you pass from 65 to 75mph...... depending on that answer the 2.2 might be best, OR the 2.75 might be best.
NOW, (glen read this please) if you are only changing the ring and pinion, you change NOTHING, except for getting a super LOW 1st gear.... the rest of the gears actually are almost the same, except for 5th , which would be much higher reving for the freeway speeds , and a closer ratio to 4th. aside from those two differnces, there is really no reason to swap out the rear end
the difference of 5th is 24% vs the 2.73. this means all gears are shifted 24% lower, and since the gear spacing for the 2.2 is already near 25% per shift, what did you acomplish?? nothing!!!!!!!
(excpect an unusally low 1st gear and a higher reving 5th)
so, in the end, there is NO logical reason for doing such a change, unless you are Glen and you like being at 4000rpm at 60mph in 2nd vs being 4000rpm at 60mph in 3rd.... (as a rough example) both cars are at 60mph and running 4000rpm.... does it really matter what the numerical gear name is??
Glen says the differneces are noticible, but it depends on the speeds you usually travel at and when you "pass a car" do you always pass from 40-50mph or do you pass from 55 to 66, or do you pass from 65 to 75mph...... depending on that answer the 2.2 might be best, OR the 2.75 might be best.
NOW, (glen read this please) if you are only changing the ring and pinion, you change NOTHING, except for getting a super LOW 1st gear.... the rest of the gears actually are almost the same, except for 5th , which would be much higher reving for the freeway speeds , and a closer ratio to 4th. aside from those two differnces, there is really no reason to swap out the rear end
the difference of 5th is 24% vs the 2.73. this means all gears are shifted 24% lower, and since the gear spacing for the 2.2 is already near 25% per shift, what did you acomplish?? nothing!!!!!!!
(excpect an unusally low 1st gear and a higher reving 5th)
so, in the end, there is NO logical reason for doing such a change, unless you are Glen and you like being at 4000rpm at 60mph in 2nd vs being 4000rpm at 60mph in 3rd.... (as a rough example) both cars are at 60mph and running 4000rpm.... does it really matter what the numerical gear name is??
08-18-2015, 04:00 PM
#55
Archive Gatekeeper
Rennlist Member
Rennlist Member
When are you guys going to understand that Kibort is terminally differentiated, and that you'll never get him to acknowledge a point, ever? If you want to reply, write out a long seasoned response, and then delete it before posting. The net effect will be the same, except that you won't have engaged.
08-18-2015, 04:12 PM
#56
Rennlist Member
by the way. formula is a mixture . equation is is a mathematical representation of a concept.
think of a formula is like the ingredients of something
an equation would have an "=" sign in it.
08-18-2015, 04:24 PM
#57
Rennlist Member
Greg, you condescending PxxK! (and i mean that in the most friendly way, because i do like you and respect the things you DO know about. )
Ive been racing competitively more than 20 years, have more race miles and successful race miles on the 928 or any other single racing platform that most anyone around, and you don't even have a college degree and think you are going to school me in physics?
as far as the gear box..... look at my countless videos... see any missshifts?... thats amature hour.. if you cant shift a car flawlessly with maybe a .001% chance of a miss shift, you dont belong in a race car unless you have a big check book
all your ' repairs" are from guys that probably are not the smoothest around. nothing wrong with that, but thats the nature of racing. i cant tell you of how many "pros" ive seen that man handle and misuse race cars. 20 years, and lots of wheel to wheel racing against seasoned pros, in money pit cars as well as those on par with my racer. many of the driver in any series shouldnt really even be out there. many are just dangerous, and certainly dont have top ability in keeping their equipment safe.
I understand that the borg warner gear box was almost too good for its own good, allowing for some bad misshifts, but, having raced the plaform for many many years, and having more races in the platform than anyone around, i can safely say, ive never had a high reving misshift. plus the layout makes it near impossible. 3rd to 2nd upshift?? pretty hard to do. 4th to 1st... impossible.
3rd to revers... also impossible. its not like the BMW where this happens ALL the time.. and i dont know what kind of snchros they have but that is a common occurrence for new racers. (and the engine blows almost always )
)Ive been racing competitively more than 20 years, have more race miles and successful race miles on the 928 or any other single racing platform that most anyone around, and you don't even have a college degree and think you are going to school me in physics?
as far as the gear box..... look at my countless videos... see any missshifts?... thats amature hour.. if you cant shift a car flawlessly with maybe a .001% chance of a miss shift, you dont belong in a race car unless you have a big check book
all your ' repairs" are from guys that probably are not the smoothest around. nothing wrong with that, but thats the nature of racing. i cant tell you of how many "pros" ive seen that man handle and misuse race cars. 20 years, and lots of wheel to wheel racing against seasoned pros, in money pit cars as well as those on par with my racer. many of the driver in any series shouldnt really even be out there. many are just dangerous, and certainly dont have top ability in keeping their equipment safe.
I understand that the borg warner gear box was almost too good for its own good, allowing for some bad misshifts, but, having raced the plaform for many many years, and having more races in the platform than anyone around, i can safely say, ive never had a high reving misshift. plus the layout makes it near impossible. 3rd to 2nd upshift?? pretty hard to do. 4th to 1st... impossible.
3rd to revers... also impossible. its not like the BMW where this happens ALL the time.. and i dont know what kind of snchros they have but that is a common occurrence for new racers. (and the engine blows almost always )
You are young and have very limited experience, which always shows, when you talk about anything related to racing. You have this tiny little "snapshot" of what is reality and have almost no clue what the "bigger picture" is. It's really humorous to read and watch you try to turn your tiny little experience into "laws" that fit everything.....while your own reality only fits in your own little tiny "pond".
I can't even begin to estimate how many race engines I've repaired that have been "stuck" in the incorrect gear on a shift, because of the Borg Warner transmissions.....certainly dozens and dozens.
Borg Warner style transmissions allow really stupid downshifts, with virtually no feedback.
I can't ever recall this happening on vehicles with transmissions equipped with "Porsche style" synchros, because if you tried to get the transmission into 2nd gear, instead of 4th gear, on a downshift, the gearshift lever let you know, instantly, that you were making a huge mistake.
One of the really great improvements (and major "cost" reducers of Porsche racing) was the introduction of the sequential gearbox.....this single change reduced the "overrev" engine damage by hundreds of thousands of dollars in the Cup Car program, alone. And this happened simply because the Borg Warner gearbox transmissions were so easy to get into the wrong gear, whereas the sequential gearbox eliminated this problem, if the driver was smart enough to be able to count.
The reality is that he Borg Warner style transmissions were great for "easier" street driving and absolutely sucked as a race transmissions, simply because of the lack of "feel" from the gearshift lever.
I won't go any further into the other reasons that Borg Warner style transmission sucked for race use....but if you look at where the gearbox oil needs to "travel" to cool down the synchro surface, compared to the Porsche style synchro, it becomes very obvious why this style transmission "crunched" the synchros so badly, once the transmissions got hot. I had to replace entire gear sets, after almost every event, because the cone where the synchro hits on the gear would get destroyed, from heat and the resulting metal transfer, on the "professional" race cars which ran these transmissions. This NEVER happened on the transmission with Porsche style synchros.....the "hot friction surface" was on the very outside of the gear, sloshing through the cooler gear oil!
I can't even begin to estimate how many race engines I've repaired that have been "stuck" in the incorrect gear on a shift, because of the Borg Warner transmissions.....certainly dozens and dozens.
Borg Warner style transmissions allow really stupid downshifts, with virtually no feedback.
I can't ever recall this happening on vehicles with transmissions equipped with "Porsche style" synchros, because if you tried to get the transmission into 2nd gear, instead of 4th gear, on a downshift, the gearshift lever let you know, instantly, that you were making a huge mistake.
One of the really great improvements (and major "cost" reducers of Porsche racing) was the introduction of the sequential gearbox.....this single change reduced the "overrev" engine damage by hundreds of thousands of dollars in the Cup Car program, alone. And this happened simply because the Borg Warner gearbox transmissions were so easy to get into the wrong gear, whereas the sequential gearbox eliminated this problem, if the driver was smart enough to be able to count.
The reality is that he Borg Warner style transmissions were great for "easier" street driving and absolutely sucked as a race transmissions, simply because of the lack of "feel" from the gearshift lever.
I won't go any further into the other reasons that Borg Warner style transmission sucked for race use....but if you look at where the gearbox oil needs to "travel" to cool down the synchro surface, compared to the Porsche style synchro, it becomes very obvious why this style transmission "crunched" the synchros so badly, once the transmissions got hot. I had to replace entire gear sets, after almost every event, because the cone where the synchro hits on the gear would get destroyed, from heat and the resulting metal transfer, on the "professional" race cars which ran these transmissions. This NEVER happened on the transmission with Porsche style synchros.....the "hot friction surface" was on the very outside of the gear, sloshing through the cooler gear oil!
08-18-2015, 04:31 PM
#58
When are you guys going to understand that Kibort is terminally differentiated, and that you'll never get him to acknowledge a point, ever? If you want to reply, write out a long seasoned response, and then delete it before posting. The net effect will be the same, except that you won't have engaged.
08-18-2015, 04:35 PM
#59
Rennlist Member
Below is your first post in this thread: The OP wants lower gears in a street car, and you jumped on him saying there is no logical reason to do so (your words). Now you backtrack and say lower rear ratios are better for certain situations. And also in your first post you state that 1st and 5th will have the biggest changes with the middle gears not so much? The transmission ratios stay the same! I think you are getting confused...
Can't you just accept the fact that a 928 with a lower rear ratio would be more fun to drive on the street?? Geez!
Can't you just accept the fact that a 928 with a lower rear ratio would be more fun to drive on the street?? Geez!
the reason is that driving on the street, by definition, will have a infinite amount of speed ranges.. this means that one gear box wont solve any issues or make it any more fun to drive because those speed ranges will always bee different. I conceded that the shorter ratio gear box will give a very low 1st gear but it also changes 5th, so that it, being not ever needed for performance driving, a ratio that is not great for overdrive purposes. So, the reason that the 2.2 is generally ideal, is that you get the good efficiency 5th and all the other gears are quite usable. in fact, ironically enough, 1st becomes more usable because it is good until 50-55mph.
again, you have to understand that the acceleration range of the car will be over varied speeds. and there is overlap. this overlap negates any performance gains unless you have a specific range of speed you want to operate at.
example.... say you want to run an autox course that has a top speed of 65mph.. this would be better for the 2.75.... if that same course had a top speed of 75mph, the 2.2 would be the better choice.
street example.... say you want to have the most punch from 55 to 80mph.... iin that case the 2.2 is the best gear box.... if you want 45 to 75 the 2.75 would be the best gear box. personally, ive driven both and i like being in the meat of 2nd gear from cruising at 40 to 45mph and acceleratring hard from speeds of 50mph to near 80mph. I also like being in 1st driving slow up to 40 mph.... if i jump on it at 40-45, a 2-75 next to me would be in 2nd and be lugging around.
its all personal preference , but i hope you get the point
example drag...... if you could get traction out of the hole with slicks and the power was fairly low in your car... the 2.75 might be best. if you have tall street tires and a lot of power, the 2.2 might work best... (these all can be proved in any drag simulator by the way.... you will be surprised how close the reality of the ET's will be by changes of the gear box.
In summary.... gear box selection, if done properly, needs to have a goal of a speed range or series of speed ranges to determine which will work out best..... this is not my idea, or my discovery, this is commonly excepted racing, physics.
so, remember gear boxes don't give you power, or even torque at any particular speed ( synonymous) it only optimizes the torque or power you have available at the rear wheels for any desired speed operating range.
08-18-2015, 04:49 PM
#60
Yes, of course Mark. Please, after over 10 years of your bull****, why don't you cop a squat on YET another rennlist thread that has any relation to a transmission.
BTW - have you EVER fvking once taken the time to tune your free engine properly?
When given the opportunity, F1 engineers made the transmissions so they could be tailored to each track visited.
That is the end of anything you can state here. Discussion over.
BTW - have you EVER fvking once taken the time to tune your free engine properly?
When given the opportunity, F1 engineers made the transmissions so they could be tailored to each track visited.
That is the end of anything you can state here. Discussion over.