TRE final drive gears.
Jun 23, 2005, 03:32 PM
#46
Originally Posted by GEARS
Yes.
Not hard at all if you have all the proper tools and all the small parts that REALLY should be replaced any time that you are in the transmission.
Jon@TRE
Not hard at all if you have all the proper tools and all the small parts that REALLY should be replaced any time that you are in the transmission.
Jon@TRE
Do you have a 5th gear replacement that would be around .79 in size sitting on a shelf ready to sell? That would narrow the gap nicely between 4th and 5th and when combined with your 3.84 final drive would give a cruise speed of 75 mph at a nice round 3,000 RPM. I think a lot of people would be interested in this when doing a transmission rebuild.
Keith
Jun 23, 2005, 03:33 PM
#47
Newbie
iTrader: (1)
Join Date: Apr 2004
Location: Bakersfield
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
Damn those trannys are CHEAP, I paid 5k for my STi 6 speed. I'm now thinking of selling my WRX and getting another Evo and build that one instead! (Our current Evo is my wife's)
Last edited by eljefe; Jun 23, 2005 at 03:38 PM.
Jun 23, 2005, 03:41 PM
#48
Evolved Member
iTrader: (9)
Join Date: Sep 2003
Location: South FL
Posts: 1,070
Likes: 0
Received 0 Likes
on
0 Posts
So just replacing the final drive would lengthen the gears? So they don't seem to "fly by" and would cause the car to feel less hyper active. LOL My dad that drives a C5 vette claims my car to drive like "hyper active child" compared to his because his gears last for ages and his power is so linear. Just a mod to think of in the future.. The car does not seem all that hyper to me but I do notice that 1-2 in particular last for seconds.
Jun 23, 2005, 05:30 PM
#49
Originally Posted by eljefe
Damn those trannys are CHEAP, I paid 5k for my STi 6 speed. I'm now thinking of selling my WRX and getting another Evo and build that one instead! (Our current Evo is my wife's)
Jon@TRE
http://www.teamrip.com/Evolution.html
Jun 23, 2005, 06:17 PM
#50
Originally Posted by ThEHiTMaN
So just replacing the final drive would lengthen the gears? So they don't seem to "fly by" and would cause the car to feel less hyper active. LOL My dad that drives a C5 vette claims my car to drive like "hyper active child" compared to his because his gears last for ages and his power is so linear. Just a mod to think of in the future.. The car does not seem all that hyper to me but I do notice that 1-2 in particular last for seconds.
When you have over 400 wheel HP it will be way more hyper seaming than it is now
Keith
Jun 23, 2005, 11:11 PM
#52
Evolved Member
iTrader: (17)
Join Date: Apr 2004
Location: 41° 59' N, 87° 54' W
Posts: 6,224
Likes: 0
Received 0 Likes
on
0 Posts
Ok, I finally got some free time and did some number crunching and have come up with a bunch of graphs for the lot of us. I used dyno charts from a stock Evo and then from my Evo to calculate the actual amount of torque the wheels put down in each gear.
Initially I was just curious about where the optimal shift points would be, which immediately turned into optimal shift points on a stock Evo vs my Evo (Vishnu stage 1 + w/ HKS 272/272 cams), which then turned into ... hmm, I wonder how that would change when using the TRE final drive. At this point I just have one thing to say ...
Ugh ... my head hurtz ...
Please feel free to correct me if my conclusions are wrong, but here's what I've come up with:
1.) someone at
did their homework, the 5 speed gear ratios are damn near perfect on a stock Evo
2.) optimal shift points on a stock Evo seem to be
1 - 2 -> ~7400 rpm
2 - 3 -> ~6900 rpm
3 - 4 -> ~7000 rpm
4 - 5 -> ~7000 rpm (aka ... who cares!)
3.) My stage 1+ with 272 cams pushes the shift points up to:
1 - 2 -> ~7600 rpm
2 - 3 -> ~7400 rpm
3 - 4 -> ~7200 rpm
4 - 5 -> ~7500 rpm
4.) Adding a final drive of 3.84 doesn't change the shift points per-se, but man does it lower torque @ the wheels ... I'm sure for drag racing it wouldn't matter that much, since the benefits of being able to run w/out shifting into 5th should outweigh any potential loss in the lower gears. But what really throws me noggin for a loop is when I try to envision the impact on a circuit, because now I'm going from having a 3rd gear with a nice wide powerband putting down ~ 1700 ft-lbs to having a wide powerband putting down just under 1500 ft-lbs. Granted the new gearing would have me going faster, but I'm not sure if that would offset the loss of torque on the pavement.
Anyways, here's the graphs. Stock Evo first...
l8r)
Initially I was just curious about where the optimal shift points would be, which immediately turned into optimal shift points on a stock Evo vs my Evo (Vishnu stage 1 + w/ HKS 272/272 cams), which then turned into ... hmm, I wonder how that would change when using the TRE final drive. At this point I just have one thing to say ...
Ugh ... my head hurtz ...
Please feel free to correct me if my conclusions are wrong, but here's what I've come up with:
1.) someone at
did their homework, the 5 speed gear ratios are damn near perfect on a stock Evo2.) optimal shift points on a stock Evo seem to be
1 - 2 -> ~7400 rpm
2 - 3 -> ~6900 rpm
3 - 4 -> ~7000 rpm
4 - 5 -> ~7000 rpm (aka ... who cares!)
3.) My stage 1+ with 272 cams pushes the shift points up to:
1 - 2 -> ~7600 rpm
2 - 3 -> ~7400 rpm
3 - 4 -> ~7200 rpm
4 - 5 -> ~7500 rpm
4.) Adding a final drive of 3.84 doesn't change the shift points per-se, but man does it lower torque @ the wheels ... I'm sure for drag racing it wouldn't matter that much, since the benefits of being able to run w/out shifting into 5th should outweigh any potential loss in the lower gears. But what really throws me noggin for a loop is when I try to envision the impact on a circuit, because now I'm going from having a 3rd gear with a nice wide powerband putting down ~ 1700 ft-lbs to having a wide powerband putting down just under 1500 ft-lbs. Granted the new gearing would have me going faster, but I'm not sure if that would offset the loss of torque on the pavement.
Anyways, here's the graphs. Stock Evo first...
l8r)
Jun 24, 2005, 06:05 AM
#54
Ludikraut, most people love the feel of the stock gearing with the stock engine power, and some even consider that gearing too short. If you look at the stock EVO chart you made compared the chart you made for your car with the 3.84's you will be putting more torque to the ground in each gear than you were stock. On a road course that means the car will fell more like it did when it was stock, but still feel more powerful.
Keith
Keith
Jun 24, 2005, 01:40 PM
#55
Evolved Member
iTrader: (17)
Join Date: Apr 2004
Location: 41° 59' N, 87° 54' W
Posts: 6,224
Likes: 0
Received 0 Likes
on
0 Posts
I don't see how you could put down more torque in each gear with the TRE final drive. If you compare the torque, gear to gear, you will put down less torque in each gear. However, having said that, if you also calculate your speed into the equation, things get a little bit more complicated, because while the RPMs that you shift at remain the same, the speed increases with the higher final drive.
I decided to make another graph, comparing the torque vs mph, with some VERY interesting results. It looks like you are pretty much going to put down almost the same amount of torque at any given speed past 1st gear, which means that you're not really going to accelerate any faster. All you've managed to do is to move your shift points further down the road so-to-speak. That may save you from having to shift into 4th/5th depending on your power level and will probably be the only time savings in a 1/4 mile run. For circuit racing it looks like the penalty really will depend on what kind of circuit I'm running on, because if it ends up having me shift more than the stock gearing, I'll probably lose some time, not to mention the extra wear on the tranny. So the TRE final drive could be awesome for a track like Road America, but too tall for something like Gingerman ... interesting stuff.
I didn't bother charting the HKS final drive, since it will just fall between the stock and TRE curves... If you want to see what changing the actual gearing would do, lemme know. Now that I have my spreadsheet setup, the graphs are easy to do.
l8r)
I decided to make another graph, comparing the torque vs mph, with some VERY interesting results. It looks like you are pretty much going to put down almost the same amount of torque at any given speed past 1st gear, which means that you're not really going to accelerate any faster. All you've managed to do is to move your shift points further down the road so-to-speak. That may save you from having to shift into 4th/5th depending on your power level and will probably be the only time savings in a 1/4 mile run. For circuit racing it looks like the penalty really will depend on what kind of circuit I'm running on, because if it ends up having me shift more than the stock gearing, I'll probably lose some time, not to mention the extra wear on the tranny. So the TRE final drive could be awesome for a track like Road America, but too tall for something like Gingerman ... interesting stuff.
I didn't bother charting the HKS final drive, since it will just fall between the stock and TRE curves... If you want to see what changing the actual gearing would do, lemme know. Now that I have my spreadsheet setup, the graphs are easy to do.
l8r)
Last edited by Ludikraut; Jun 24, 2005 at 01:42 PM.
Jun 24, 2005, 02:18 PM
#56
Originally Posted by Ludikraut
I don't see how you could put down more torque in each gear with the TRE final drive. If you compare the torque, gear to gear, you will put down less torque in each gear.
For example, in 3rd gear on the stock EVO with stock gearing you are putting down 875 lb-ft of torque at the start of the curve with 1,375 at the highest peak and 850 lb-ft at the end of the curve. Your Vishnu stage 1+ car with TRE gears you would have 1,150 lb-ft at the start of the curve, 1,500 lb-ft of torque at the peak, and 1,000 lb-ft of torque at the end of 3rd gear. That means that your Vishnu stage 1+ car with TRE gears will feel faster and accelerate harder in each gear than a stock EVO on stock gearing. Now, if you don't consider the stock gearing "frantic" at your power level, then stick with the stock gear set.... but if you feel like you are rowing for all you are worth and the extra shifting is what is holding you back the TRE gears are the way to go.
Keith
Jun 24, 2005, 02:43 PM
#57
Evolved Member
iTrader: (17)
Join Date: Apr 2004
Location: 41° 59' N, 87° 54' W
Posts: 6,224
Likes: 0
Received 0 Likes
on
0 Posts
Ah, ok, got it. Yeah, I noticed the massive torque increase between stock and modded. I'll post another set of graphs once the AMS kit is installed and tuned. It will be very interesting to see how the stock gear ratios do when pushed to 9000 rpm. 
l8r)
l8r)
Jun 24, 2005, 03:45 PM
#58
Originally Posted by Ludikraut
I don't see how you could put down more torque in each gear with the TRE final drive. If you compare the torque, gear to gear, you will put down less torque in each gear. However, having said that, if you also calculate your speed into the equation, things get a little bit more complicated, because while the RPMs that you shift at remain the same, the speed increases with the higher final drive.
I decided to make another graph, comparing the torque vs mph, with some VERY interesting results. It looks like you are pretty much going to put down almost the same amount of torque at any given speed past 1st gear, which means that you're not really going to accelerate any faster. All you've managed to do is to move your shift points further down the road so-to-speak. That may save you from having to shift into 4th/5th depending on your power level and will probably be the only time savings in a 1/4 mile run. For circuit racing it looks like the penalty really will depend on what kind of circuit I'm running on, because if it ends up having me shift more than the stock gearing, I'll probably lose some time, not to mention the extra wear on the tranny. So the TRE final drive could be awesome for a track like Road America, but too tall for something like Gingerman ... interesting stuff.
I didn't bother charting the HKS final drive, since it will just fall between the stock and TRE curves... If you want to see what changing the actual gearing would do, lemme know. Now that I have my spreadsheet setup, the graphs are easy to do.
l8r)
I decided to make another graph, comparing the torque vs mph, with some VERY interesting results. It looks like you are pretty much going to put down almost the same amount of torque at any given speed past 1st gear, which means that you're not really going to accelerate any faster. All you've managed to do is to move your shift points further down the road so-to-speak. That may save you from having to shift into 4th/5th depending on your power level and will probably be the only time savings in a 1/4 mile run. For circuit racing it looks like the penalty really will depend on what kind of circuit I'm running on, because if it ends up having me shift more than the stock gearing, I'll probably lose some time, not to mention the extra wear on the tranny. So the TRE final drive could be awesome for a track like Road America, but too tall for something like Gingerman ... interesting stuff.
I didn't bother charting the HKS final drive, since it will just fall between the stock and TRE curves... If you want to see what changing the actual gearing would do, lemme know. Now that I have my spreadsheet setup, the graphs are easy to do.
l8r)
Excellent work Ludikraut!!!
The whole trick to the gearing is you will knock time off your E.T. because you can stay in 1st gear longer before you have to shift.
As we all heard, "The race is won in the first 60 feet.", and this is true unless you have an assload of power to chase down what just left you at the tree and can rev it to the moon in 4th gear.
With the lower ratio'd gears you can stay in 1st gear longer allowing you to get up to a higher speed before you have to break power for the 2nd gear shift and you don't have to rev it way past your power curve at the big end of the 1320 because 4th gear goes forever.
Another thing to note is the lower torque output coming out of the transmission. However, if you are trying to cut the same short time as you would with the OEM final drive you will be putting more strain on the gearing upstream of the final drive to obtain the same rate of acceleration.
But the EVO transmission has a couple things going for it especially when compared to the older DSM/EVO 1-3 transmissions. The shaft center spacing and the gears are substantially wider and all this translates to a much higher torque capacity.
Even with that said, you should still take it easy in first gear instead of bouncing it off the rev-limiter and side stepping the clutch. First gear is narrower than the old DSM transmissions by 2mm but the metal is pretty tough and wears out our tooling quickly so even with the reduction in width it'll probably hang in there as long as people don't shock load it with abusive clutch dumps.
Thanks for the space!!!
Jon@teamrip.com