Gear ratios...
#136
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I've driven the GT4 back to back against the Cayman R and 997.1 C2S, all 6-sp manual. On the road, the latter two feel significantly peppier than the GT4, despite having less power and peak torque, whereas the exact opposite should be the case. This can only be explained by the torque curves and how they work with the gearing in each car.
The 991S has more power,less drivetrain loss and better traction. One thing I've noticed in the GT4 that I didn't notice in the 991 S is wheel hopping. If you throw the Powerkit in you're talking 45HP more than the GT4. You feel that! The talk we hear during GT cars presentation about " GT horsepower " is just marketing talk. The GT4 makes exactly what it is rated for. Same goes for the GT3. It's been proven on the dyno.
The only complaint I have is the 2nd gear,that's it. If you want to go to the redline and shift it takes a while... But I've learned to live with that. Most drivers don't have that fine tuned sensibility. Perhaps I'm most drivers... And that's ok...
I wouldn't risk losing the warranty for the " gains " I'm reading about here.
One thing that the GT4 is not it's " sluggish ". Pete,this thread combined with your other one and I'm starting to believe your GT4 is defective...![Confused](https://rennlist.com/forums/images/smilies/confused.gif)
The only complaint I have is the 2nd gear,that's it. If you want to go to the redline and shift it takes a while... But I've learned to live with that. Most drivers don't have that fine tuned sensibility. Perhaps I'm most drivers... And that's ok...
I wouldn't risk losing the warranty for the " gains " I'm reading about here.
One thing that the GT4 is not it's " sluggish ". Pete,this thread combined with your other one and I'm starting to believe your GT4 is defective...
![Confused](https://rennlist.com/forums/images/smilies/confused.gif)
Mark brings something important, as others have, in that to fix the feeling, we need to look at some numbers. A simple, digestible comparison of the effective gear ratios in 1-5 and 6th between a manual 991S and a GT4 would be very interesting—as would the max speed in each gear. That may be a bit above my pay grade, or involve that pesky stuff called math. From there, it would be easier to chart a road to fixing the feeling so many of us don't like. And that's that "sluggish" you speak of. I feel like I can set the time on my wristwatch while waiting for the GT4 to wake up in second gear. I can set it and your wrist watch's while waiting for 5000 rpm in third. ![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
We're talking about how the power delivery of the car feels on the road, in comparison with other manual Porsches. No theoretical argument can override that empirical experience. If it feels sluggish, it feels sluggish. The question is how to fix that, not how to rationalize the problem away.
That's what we need to do. I lost a lot of that type of info when I left Pano, as I left it with the club. I can do some digging for speeds in gear, or someone may have it handy. Per Porsche, the gear ratios are:
991S (PDK in parenthesis)
1st 3.91 (3.91)
2nd 2.29 (2.29)
3rd 1.55 (1.65)
4th 1.30 (1.30)
5th 1.08 (1.08)
6th 0.88 (0.88)
7th 0.71 (0.62)
F/D 3.44:1 (3.44:1)
981S (PDK in parenthesis)
1st 3.31 (3.91)
2nd 1.95 (2.29)
3rd 1.41 (1.65)
4th 1.13 (1.30)
5th 0.95 (1.08)
6th 0.81 (.88)
7th -- (0.62)
F/D 3.89 (3.89)
This info may have appeared earlier in the thread, but maybe it can be filled out with the maximum speeds in gear, and perhaps even a better way of comparing the effective gear ratios given the 3.44 vs 3.89 final drives. I suspect that means that, since custom gears would be required, those gears could be made to take into account the difference in final drive between the two while trying to create effective parity with the 991S in gears 1-5 plus 7. If, of course, that was the goal. It would be mine, and I suspect it would be a good setup for a lot of GT4 owners. Or maybe it could be optimized from there if a gear expert laid out a better plan to maximize acceleration and flexibility in gears 1-5 with a nice, tall cruising cog for 6th.
991S (PDK in parenthesis)
1st 3.91 (3.91)
2nd 2.29 (2.29)
3rd 1.55 (1.65)
4th 1.30 (1.30)
5th 1.08 (1.08)
6th 0.88 (0.88)
7th 0.71 (0.62)
F/D 3.44:1 (3.44:1)
981S (PDK in parenthesis)
1st 3.31 (3.91)
2nd 1.95 (2.29)
3rd 1.41 (1.65)
4th 1.13 (1.30)
5th 0.95 (1.08)
6th 0.81 (.88)
7th -- (0.62)
F/D 3.89 (3.89)
This info may have appeared earlier in the thread, but maybe it can be filled out with the maximum speeds in gear, and perhaps even a better way of comparing the effective gear ratios given the 3.44 vs 3.89 final drives. I suspect that means that, since custom gears would be required, those gears could be made to take into account the difference in final drive between the two while trying to create effective parity with the 991S in gears 1-5 plus 7. If, of course, that was the goal. It would be mine, and I suspect it would be a good setup for a lot of GT4 owners. Or maybe it could be optimized from there if a gear expert laid out a better plan to maximize acceleration and flexibility in gears 1-5 with a nice, tall cruising cog for 6th.
it would be interesting to see the trade offs VISUALLY. this the ONLY way to reallly have a logical discussion of what is "better" vs all the feelings that have been posted. so far the only logical information , that is based on feelings , is as true as it gets.. on the hyway, running the car at 5% lower RPM is better in top gear for cruising.. i think most of us agree here. there is no performance advantage... just a feeeling based on engine RPM sound and possibly engine efficiency... but thats an entirely different reason for the debate and discussion ehre... after all, matt at GTGears doesnt want to touch 6th because he feels the max theoretical speed is high enough as he said. so, the question becomes what are the gains to be had by going back and forth between the 991S and the GT4?? and by the way, i dont have any axe to grind with Matt and have no dog in the race either... I just like the subject matter. He knows his stuff and is very active in giving relevant information here on gears and costs............ the main thing that the group has to understand though, is " what will be accomplished " by a gear change .. what are teh advantages vs disadvantages, as matt knows, there are ALWAYS trade offs.
#137
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Yes, I see ring and pinions wear out all the time. In fact, until the GT4 3rd gear failures, it was ALWAYS the failure point on the Cayman racecars. And since Porsche won't sell you a ring and pinion, when it happens you have to buy a new gearbox. In the 996 and 997 Cup Cars a ring and pinion lasts about 80-100 hours. For the Club and GT3 Challenge and Pirelli Driver's Cup racers that's 2-3 years. In IMSA we generally replace them after Daytona and put the used one in the spares pile and can get most of the rest of a season out of a new one.
![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
i guess the major issue i have with the pinion gear discussion , is that 5% is not going to change the wear factor that much.. in fact, its seeing less torque at the gear face when spinning faster, so it should last longer, but the bearing should wear out faster , right? but if its spining faster and wearing out, due to speed, maybe better lubrication should be looked at or cooling . clearly, if its wearing out, its due to gear spline friction and 5% changes are going to make 5% change correct?
Mark,
The gearbox has been using the same ratios since the 987.1 S engine. They didn't optimize anything for the GT4. They pulled from the parts bin. Though, as has been pointed out here, the 2.7 was given shorter ratios than the GT4. Don't confuse the GT4 with the Clubsport racecar. The Clubsport is a PDK and has very good ratios, ratios that are better optimized for the track.
The gearbox has been using the same ratios since the 987.1 S engine. They didn't optimize anything for the GT4. They pulled from the parts bin. Though, as has been pointed out here, the 2.7 was given shorter ratios than the GT4. Don't confuse the GT4 with the Clubsport racecar. The Clubsport is a PDK and has very good ratios, ratios that are better optimized for the track.
Lets post the top MPH vs gear ratio for what is looked at for a change. that way it all will make much more sense one way or another.
#138
Nordschleife Master
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Mark,
we aren't talking about a 5% change. The options for cayman are 3.89 and 4.55. I suggest you re-read the thread from the beginning. It is all there. You on going confusion is just distracting from the core discussion.
we aren't talking about a 5% change. The options for cayman are 3.89 and 4.55. I suggest you re-read the thread from the beginning. It is all there. You on going confusion is just distracting from the core discussion.
#139
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
i read this thread from beginning to end.. many have different perspectives and the confusion is in that there are so many options, so many goals and so many perceptions. thats why i suggested to just put the stock gears that are being discusses, and their related top speed in each gear and match them up with the "options" available.
GT4 = speed in each gear at redline
GT4 CS = speed in each gear at redline
CarerraS = speed in each gear at redline
GT3cup car= speed in each gear at redlne
cayman = speed in ead gear at redine.
then, we cna discuss advantages and disadvantages.
for example.. early in the discussion , there is a perception that the big spread of 1st to 2nd is a problem. this is done on purpose... the Aston martin and maseratti do this with their granzano gear boxes. why? (and it makes perfect sense) because you use 1st just to get out of the parkinglot out of the paddock,etc... you dont really use 1st on the street or track that much. the AMvantage 1st gear i think is 12:1..... i think its perfect. you can chug along in traffic witih minimal clutch wear and full clutch release at slow speeds. (redline is 7700rpm) then, there is a big drop to 2nd and the rest of the gears to 6th are very close. why?? to keep the car in the powerband. making a shorter 2nd gear that has redline speeds of 40mph or 45mph is not optimal.. why, because its tough to downshift into such a low gear on the track, AND many of the turns,( when driving at good -lap --time- clips) are around 45mph, so 2nd gear is the gear of choice anyway.... you are traction limited in 2nd initially, so its ok that it starts out at a little less hp range, but on the exit, you are full tilt and in the max HP range. 5500rpm to 7700rpm. this is the goal usually.
75 to 80mph 2nd gears are quite normal.... 100 to 120mph 3rd gears work well and 4ths from 130 to 155 work well too. most only have 3 gears to play with at the track , but if you can get 4 or 5 gears used to stay in the HP range , then thats all the better at the cost of rowing the gear box more.
so, if you really want to see what will work best, we need to see the 3 to 4 options of max MPH in each gear on a matrix . the trade offs willl be obvious.
also , keep in mind. this alll changes with the Hp available, and the track are street use your using the car for too. in other words, as the car gets more HP by design or improvements, the top speeds on any give straight will change, this requires the gear set changes to keep optimal. sometimes individual gears need to change... other times, rear end ratio needs to change. its a moving tartget!
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
#140
Nordschleife Master
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Mark,
I'm not moving the goal posts. I gave an example, with math, about why a shorter ratio wears out more quickly. That's all it was. You are the one who has latched on to the particular ratios and started making arguments for or against. Hell, you started with saying that I was defending the 3.44 as better, which was so far off in the weeds.
Since you haven't read the original final drive thread, which was bumped, and aren't paying close attention in this thread I'll spoon feed you. There are two options for a Cayman R/P, 3.89 (stock) and 4.55 (German aftermarket). Pete has the opinion, which I agree with, that the 4.55 F/D isn't a good solution, for a number of reasons, one of which is accelerated wear. And now you are caught up since you can't seem to be bothered with the hard details, like which final drives and which gear ratios are actually in these cars. You keep going on about how there is no universal best and that you need to know this and that. We know this and that. You are the one in the conversation who doesn't seem to get it.
The parameters for where Pete, and others here, are seeking "best" performance, and to improve upon the stock gearing are pretty clearly defined. Get with the program.
On second thuought, nevermind. I'm hiding your posts again. It was a mistake to give you another chance. I'm done wasting my time on you.
I'm not moving the goal posts. I gave an example, with math, about why a shorter ratio wears out more quickly. That's all it was. You are the one who has latched on to the particular ratios and started making arguments for or against. Hell, you started with saying that I was defending the 3.44 as better, which was so far off in the weeds.
Since you haven't read the original final drive thread, which was bumped, and aren't paying close attention in this thread I'll spoon feed you. There are two options for a Cayman R/P, 3.89 (stock) and 4.55 (German aftermarket). Pete has the opinion, which I agree with, that the 4.55 F/D isn't a good solution, for a number of reasons, one of which is accelerated wear. And now you are caught up since you can't seem to be bothered with the hard details, like which final drives and which gear ratios are actually in these cars. You keep going on about how there is no universal best and that you need to know this and that. We know this and that. You are the one in the conversation who doesn't seem to get it.
The parameters for where Pete, and others here, are seeking "best" performance, and to improve upon the stock gearing are pretty clearly defined. Get with the program.
On second thuought, nevermind. I'm hiding your posts again. It was a mistake to give you another chance. I'm done wasting my time on you.
#141
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Matt, sorry i got lost in the conversation then.... i tried to follow it best i could, but from the start there were several options and options for the gearing situation. thanks for laying it out clearer. i was mainly addressing that the gear ratios and their shifts come with trade offs that are not usually apparent at first glance. so, yes, it seems that the 4:5:1 gear box would definitely give more wear and probably require new gears as well, because that would a substantial change to overall ratios. (thatk's where you come in with new gears i would think).
anyway, gearing is always a lengthy discussion and what makes it more involved is the varied use cases.... track, which track, hyway, change of power, economy for the hyway, and of course "driveability", which comes into all street conversations.
anyway, ill let you and the others take it from here.
Mark
anyway, gearing is always a lengthy discussion and what makes it more involved is the varied use cases.... track, which track, hyway, change of power, economy for the hyway, and of course "driveability", which comes into all street conversations.
anyway, ill let you and the others take it from here.
Mark
Mark,
I'm not moving the goal posts. I gave an example, with math, about why a shorter ratio wears out more quickly. That's all it was. You are the one who has latched on to the particular ratios and started making arguments for or against. Hell, you started with saying that I was defending the 3.44 as better, which was so far off in the weeds.
Since you haven't read the original final drive thread, which was bumped, and aren't paying close attention in this thread I'll spoon feed you. There are two options for a Cayman R/P, 3.89 (stock) and 4.55 (German aftermarket). Pete has the opinion, which I agree with, that the 4.55 F/D isn't a good solution, for a number of reasons, one of which is accelerated wear. And now you are caught up since you can't seem to be bothered with the hard details, like which final drives and which gear ratios are actually in these cars. You keep going on about how there is no universal best and that you need to know this and that. We know this and that. You are the one in the conversation who doesn't seem to get it.
The parameters for where Pete, and others here, are seeking "best" performance, and to improve upon the stock gearing are pretty clearly defined. Get with the program.
On second thuought, nevermind. I'm hiding your posts again. It was a mistake to give you another chance. I'm done wasting my time on you.
I'm not moving the goal posts. I gave an example, with math, about why a shorter ratio wears out more quickly. That's all it was. You are the one who has latched on to the particular ratios and started making arguments for or against. Hell, you started with saying that I was defending the 3.44 as better, which was so far off in the weeds.
Since you haven't read the original final drive thread, which was bumped, and aren't paying close attention in this thread I'll spoon feed you. There are two options for a Cayman R/P, 3.89 (stock) and 4.55 (German aftermarket). Pete has the opinion, which I agree with, that the 4.55 F/D isn't a good solution, for a number of reasons, one of which is accelerated wear. And now you are caught up since you can't seem to be bothered with the hard details, like which final drives and which gear ratios are actually in these cars. You keep going on about how there is no universal best and that you need to know this and that. We know this and that. You are the one in the conversation who doesn't seem to get it.
The parameters for where Pete, and others here, are seeking "best" performance, and to improve upon the stock gearing are pretty clearly defined. Get with the program.
On second thuought, nevermind. I'm hiding your posts again. It was a mistake to give you another chance. I'm done wasting my time on you.
Last edited by mark kibort; 12-05-2016 at 05:45 PM.
#142
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Dam nit GTgears
Even so I can't see his posts (but see he is posting) its obvious that this thread has now been "kiborted".
Even so I can't see his posts (but see he is posting) its obvious that this thread has now been "kiborted".
![banghead](https://rennlist.com/forums/graemlins/banghead.gif)
#143
Rennlist Member
Join Date: Jan 2016
Location: On a pygmy pony over by the dental floss bush
Posts: 3,309
Received 618 Likes
on
422 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I believe you are right. I'm thinking about 4 years down the road when most of the warranties on GT4s are expiring, there may be more numbers of enthusiasts wanting a custom gearbox in their cars.
#144
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Way back in the day, when I was seriously racing an MGB in SCCA, I had 6 different ring and pinion sets. These were 3.90 (stock), 4.11, 4.30, 4.55, 4.88, and 5.12. I bought the 5.12 when I was into hill-climbing but found it useful at tracks with short straights such as Marlboro (really dating myself) and Waterford Hills. I switched them out depending on the track I was racing hoping to red line 4th gear just before the end of the longest straight. At the SCCA Run Offs at Road Atlanta I changed for the "Wet" qualy. Guess which destroyed itself first? The 5.12 which for sure had the least miles on it.
#145
Nordschleife Master
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
To Bill's point the main reason Porsche Motorsports dropped the 5.00 Cup cwp was because they only lasted 15-20 hours. People were trying to race certain 24 hour races and dnf-ing because of gearbox failures. Not good press for a company with such an endurance pedigree.
#146
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Wow! What a discussion. But I am totally confused now. Everyone has been complaining that 2nd is too tall. .. 80+mph at redline! .. not peppy enough in 2nd .. don't get to use the gears .. and so on.
And now that there seems a pretty straightforward way of reducing max. speed in 2nd into the same range where most other P-cars are (996 GT3 was 75mph IIRC), the argument moves to -- all wrong - the gears are just fine ??
FWIW, I am in Dallas and the straights on the local track require 4th, but not close to max. speed. F1 tracks may be different, but from my vantage point, less tall-ness would result in more power-delivery on average.
And now that there seems a pretty straightforward way of reducing max. speed in 2nd into the same range where most other P-cars are (996 GT3 was 75mph IIRC), the argument moves to -- all wrong - the gears are just fine ??
FWIW, I am in Dallas and the straights on the local track require 4th, but not close to max. speed. F1 tracks may be different, but from my vantage point, less tall-ness would result in more power-delivery on average.
#147
Rennlist Member
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Holy thread gone off the tracks. I think this thing got drive-by'd.
The good news is I think it covered a lot of good ground and had a lot of good inputs and perspectives. The only thing missing from my standpoint is to figure the right set of ratios to mimic gears 1-5 and 7 from the 991-1S in light of the GT4's stock R&P. That would also leave people with 2-3 sixth-gear ratios to choose from between the stock 6th and GT's offerings.
The result is an evergreen thread with info waiting for a time when 20 (?) GT4 owners are willing to step up to fully re-gear their GT4s...which may be a matter of warranty window above all else.
The good news is I think it covered a lot of good ground and had a lot of good inputs and perspectives. The only thing missing from my standpoint is to figure the right set of ratios to mimic gears 1-5 and 7 from the 991-1S in light of the GT4's stock R&P. That would also leave people with 2-3 sixth-gear ratios to choose from between the stock 6th and GT's offerings.
The result is an evergreen thread with info waiting for a time when 20 (?) GT4 owners are willing to step up to fully re-gear their GT4s...which may be a matter of warranty window above all else.
#148
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Wow! What a discussion. But I am totally confused now. Everyone has been complaining that 2nd is too tall. .. 80+mph at redline! .. not peppy enough in 2nd .. don't get to use the gears .. and so on.
And now that there seems a pretty straightforward way of reducing max. speed in 2nd into the same range where most other P-cars are (996 GT3 was 75mph IIRC), the argument moves to -- all wrong - the gears are just fine ??
FWIW, I am in Dallas and the straights on the local track require 4th, but not close to max. speed. F1 tracks may be different, but from my vantage point, less tall-ness would result in more power-delivery on average.
And now that there seems a pretty straightforward way of reducing max. speed in 2nd into the same range where most other P-cars are (996 GT3 was 75mph IIRC), the argument moves to -- all wrong - the gears are just fine ??
FWIW, I am in Dallas and the straights on the local track require 4th, but not close to max. speed. F1 tracks may be different, but from my vantage point, less tall-ness would result in more power-delivery on average.
There was SO much talk on another GT4 racing discussion where 2nd was never used because they (some said) were scared to downshift into 2nd due to too much torque. NJMP turn 5 for example. it seemed obvious to me, and others that a downshift was needed there. Also, this was seeen around the "uphill /downhill" area of LimeRock. Folks were not downshfting and just bogging out of a turn in 4th where 3rd could have been easily selectred after big bend , and through uphill and downhill for an average HP gain of near 50hp for 5-7 seconds!....... the point is, if its street driveability goals, or auto x where you would be in the 30-70mph range for a lot of the time, sure, that calls for a change. I just dont see the need and would be interested in the top speed in each gear that is desired with the mix of 991 and GT4 ratios.
with the wide HP spread mated to the close gears, each gear keeps the RPM in the max HP range, so there is nothing to optimize after 3rd gear by changing a ratio. (racing perspective). the old GT3 had a very peaky HP curve..... closer gears were much more valuable, especially down at the lower speeds.. you could give up close to 100hp with a GT3 if you had GT4 gear spacing 1-2nd gear.
![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
I dont mean to argue any points here. just tossing some info out there because its an interesting topic to me and ive played around, extensively with gear ratio changes and seen how those changes effect lap time and racing strategy optimization.
#149
Nordschleife Master
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
There was SO much talk on another GT4 racing discussion where 2nd was never used because they (some said) were scared to downshift into 2nd due to too much torque. NJMP turn 5 for example. it seemed obvious to me, and others that a downshift was needed there. Also, this was seeen around the "uphill /downhill" area of LimeRock. Folks were not downshfting and just bogging out of a turn in 4th where 3rd could have been easily selectred after big bend , and through uphill and downhill for an average HP gain of near 50hp for 5-7 seconds!....... the point is, if its street driveability goals, or auto x where you would be in the 30-70mph range for a lot of the time, sure, that calls for a change. I just dont see the need and would be interested in the top speed in each gear that is desired with the mix of 991 and GT4 ratios.
https://rennlist.com/forums/racing-a...n-the-gt4.html
#150
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
You talked about a change of gearing by Porsche with the GT4 as it might hurt performance and create some model differentiation. You do realize that if you operate in the max HP range, there is no change of gearing that will increase rear wheel forces,, correct? In other words, if you go to the shorter 2nd gear, do you increase 2nd gear forces at the wheels? Most people think you do because you are getting more mechanical forces out of a shorter gear, BUT if you are already at max Hp levels, 55mph to 80mph, the rear wheel forces stay the same..... no gain! (seems couner intuitive, but it is true) And certainly every gear after that (3rd through 6th), if you are in the 6000 to 7700rpmm range, there is no gain possible by making any gear shorter. the closeness of the gears keep the RPM in the max HP range (6000rpm to 7800rpm) and that max HP range creates max torque at the wheels. this is a commonly forgotten principle of gearing and optimizing rear wheel forces.
what im saying above is my only point. there is a void, as the thread started out pointing out, from 1st to 2nd......it's at the top of a very short 1st gear and at the beginning of second.. around 45mph.... but after 55 and to 190mph, (if you can get there) there is no areas where the stock gearing doesnt fully utilize the max HP range of the car.
as far as lime rock or NJMP, there was debate on whether to use 2nd going into turn 5. it seems clear to me that in a GT4 it is a perfect gear for an extra 50-75hp punch out of that turn, with the wheels near straight. clearly at lime rock, going into "uphill" and through "downhill" could use 3rd as well, as the goal here is to keep the car over 6000rpm at all times. the gear box looks pretty optimal for these tracks and many others. (from strictly a track perspective, not the hyway perspective)
edit: Matt. I went to that link.. yes, that was an "interesting discussion thread" but its the message is typfied by one of my strongest critics in this post. the point is.... the GT4 is geared pretty welll for the track......and the changes discussed here might hurt overall performance, sans a change of 2nd, for reasons made very clear in that discussion . https://rennlist.com/forums/racing-a...l#post13620799
Last edited by mark kibort; 12-06-2016 at 12:58 PM.