How does your GS430 feel with a 3.76 LSD compared to stock?
02-06-11, 08:35 AM
#1
How does your GS430 feel with a 3.76 LSD compared to stock?
For those that have done the Supra TT auto LSD with 3.76 gearing, how does your GS430 feel driving?
Is your highway cruising RPM much higher? Does the transmission still shift butter smooth like with the stock gearing?
I'm just wondering how the tranny would react to the new gearing, I hope there won't be any funny business like hesitation to be in the right gears and so forth...
Is your highway cruising RPM much higher? Does the transmission still shift butter smooth like with the stock gearing?
I'm just wondering how the tranny would react to the new gearing, I hope there won't be any funny business like hesitation to be in the right gears and so forth...
02-06-11, 09:05 AM
#2
For those that have done the Supra TT auto LSD with 3.76 gearing, how does your GS430 feel driving?
>> less hesitation, it's like the car is more 'awake' (for the lack of better word).
Is your highway cruising RPM much higher? Does the transmission still shift butter smooth like with the stock gearing?
>> highway cruising rpm is higher. transmission still shifts smoothly
I'm just wondering how the tranny would react to the new gearing, I hope there won't be any funny business like hesitation to be in the right gears and so forth...
>> it'll be fine. the only complaint I kiiiiiiinda have is that when you're stuck in traffic at crawling speeds (I90 in the morning) the transmission sometimes feels like it doesnt know if it wants to be in 2nd or 3rd. but thats an easy problem solved by selecting 2 in M. Also it's so minor you probably won't notice it unless youre stuck in traffic everyday.
>> less hesitation, it's like the car is more 'awake' (for the lack of better word).
Is your highway cruising RPM much higher? Does the transmission still shift butter smooth like with the stock gearing?
>> highway cruising rpm is higher. transmission still shifts smoothly
I'm just wondering how the tranny would react to the new gearing, I hope there won't be any funny business like hesitation to be in the right gears and so forth...
>> it'll be fine. the only complaint I kiiiiiiinda have is that when you're stuck in traffic at crawling speeds (I90 in the morning) the transmission sometimes feels like it doesnt know if it wants to be in 2nd or 3rd. but thats an easy problem solved by selecting 2 in M. Also it's so minor you probably won't notice it unless youre stuck in traffic everyday.
02-07-11, 06:50 AM
#5
However, it is faster at any other speed...because if you would race say...a stock GS4XX to 65mph you would be a good amount ahead. Or if you race to only 55mph, you will be ahead. But to exactly 60mph...you would most likely lose by a hair. The car will accelerate much faster at speed due to the aggressive gearing.
As a side note, you will lose 1-2mpg of gas. At 80mph you will be at 3000rpms as opposed to 2600rpms with the stock gearing. Also, top speed is now mechanically limited to around 132mph, instead of 147mph (electronically limited).
02-07-11, 11:17 AM
#6
Lexus Champion
As rock points out this change in gearing requires shifting to 3rd to reach 60mph and this adds the slow shifting time to the count so the net difference is about equal.
The change in gearing gives MORE torque at the rear wheels in every gear at any give RPM. The TWIST is that with a hard rev limit of 6300rpm this improvement comes at a COST... As noted with the 3.77 ratio the car shifts out of 2nd gear at 59mph while with 3.27 ratio the same shift happens at 68mph. These numbers are calculated at 6150rpm which is realistically the highest consistent shift point without hitting the limiter.
Looking at the 1st to 2nd shift the respective speeds are 38mph and 44mph.
2nd to 3rd are 59mph and 68mph.
3rd to 4th are 91mph and 105mph.
4th to 5th are 129mph and 149mph.
What do these numbers mean for REAL world driving performance?
From 0mph to 38mph the 3.77 has the torque advantage.
From 38mph to 44mph the 3.27 has the torque advantage.
From 44mph to 59mph the 3.77 has the torque advantage.
From 59mph to 68mph the 3.27 has the torque advantage.
From 68mph to 91mph the 3.77 has the torque advantage.
From 91mph to 105mph the 3.27 has the torque advantage.
From 105mph to 128mph the 3.77 has the torque advantage. (top speed reached for the 3.77)
From 128mph to 149mph the 3.27 has the torque and speed advantage.
So, if the race started at say 90mph the stock geared car would be significantly ahead of the 3.77 car at 105mph.
The 3.77 car should catch and likely pass the 3.27 car to 128mph and then of course the 3.27 car would run away from the speed limited 3.77 car.
The BEST part about the gear change is the FEEL of the car is snappy and quicker even though in actual timed performance the difference is minimal. Of course if you also recieved the torsen or LSD differential you should have an advantage off the line... unless the "stock" car has the "free" lsd mod
BTW, do not dismiss the FEEL component above as it makes driving much more fun and is certainly one of the reasons I talk about it so often with regards to exhaust mods.
Note: the stock ratio is 3.266 which rounds to 3.27. The Supra ratio is 3.769 which rounds to 3.77. Most will recognize 3.76. Another way to think about this would be 3.3 vs 3.8. The 3.3 multiplies the engine driveshaft torque by 3.3 times, and, you guessed it... the 3.8 multiplies the driveshaft torque by 3.8 times.
The driveshaft is of course the tranny output and the transmission multiplies the engine torque by whatever gear is being used PLUS whatever the torque converter has multiplied. These numbers can get impressive and can be as high as 3000 pound feet at the wheels. Yes, I said 3000 pounds of torque AT the wheels.
The change in gearing gives MORE torque at the rear wheels in every gear at any give RPM. The TWIST is that with a hard rev limit of 6300rpm this improvement comes at a COST... As noted with the 3.77 ratio the car shifts out of 2nd gear at 59mph while with 3.27 ratio the same shift happens at 68mph. These numbers are calculated at 6150rpm which is realistically the highest consistent shift point without hitting the limiter.
Looking at the 1st to 2nd shift the respective speeds are 38mph and 44mph.
2nd to 3rd are 59mph and 68mph.
3rd to 4th are 91mph and 105mph.
4th to 5th are 129mph and 149mph.
What do these numbers mean for REAL world driving performance?
From 0mph to 38mph the 3.77 has the torque advantage.
From 38mph to 44mph the 3.27 has the torque advantage.
From 44mph to 59mph the 3.77 has the torque advantage.
From 59mph to 68mph the 3.27 has the torque advantage.
From 68mph to 91mph the 3.77 has the torque advantage.
From 91mph to 105mph the 3.27 has the torque advantage.
From 105mph to 128mph the 3.77 has the torque advantage. (top speed reached for the 3.77)
From 128mph to 149mph the 3.27 has the torque and speed advantage.
So, if the race started at say 90mph the stock geared car would be significantly ahead of the 3.77 car at 105mph.
The 3.77 car should catch and likely pass the 3.27 car to 128mph and then of course the 3.27 car would run away from the speed limited 3.77 car.
The BEST part about the gear change is the FEEL of the car is snappy and quicker even though in actual timed performance the difference is minimal. Of course if you also recieved the torsen or LSD differential you should have an advantage off the line... unless the "stock" car has the "free" lsd mod
BTW, do not dismiss the FEEL component above as it makes driving much more fun and is certainly one of the reasons I talk about it so often with regards to exhaust mods.
Note: the stock ratio is 3.266 which rounds to 3.27. The Supra ratio is 3.769 which rounds to 3.77. Most will recognize 3.76. Another way to think about this would be 3.3 vs 3.8. The 3.3 multiplies the engine driveshaft torque by 3.3 times, and, you guessed it... the 3.8 multiplies the driveshaft torque by 3.8 times.
The driveshaft is of course the tranny output and the transmission multiplies the engine torque by whatever gear is being used PLUS whatever the torque converter has multiplied. These numbers can get impressive and can be as high as 3000 pound feet at the wheels. Yes, I said 3000 pounds of torque AT the wheels.
Last edited by JBrady; 02-07-11 at 11:25 AM.
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02-08-11, 06:20 AM
#9
As rock points out this change in gearing requires shifting to 3rd to reach 60mph and this adds the slow shifting time to the count so the net difference is about equal.
The change in gearing gives MORE torque at the rear wheels in every gear at any give RPM. The TWIST is that with a hard rev limit of 6300rpm this improvement comes at a COST... As noted with the 3.77 ratio the car shifts out of 2nd gear at 59mph while with 3.27 ratio the same shift happens at 68mph. These numbers are calculated at 6150rpm which is realistically the highest consistent shift point without hitting the limiter.
Looking at the 1st to 2nd shift the respective speeds are 38mph and 44mph.
2nd to 3rd are 59mph and 68mph.
3rd to 4th are 91mph and 105mph.
4th to 5th are 129mph and 149mph.
What do these numbers mean for REAL world driving performance?
From 0mph to 38mph the 3.77 has the torque advantage.
From 38mph to 44mph the 3.27 has the torque advantage.
From 44mph to 59mph the 3.77 has the torque advantage.
From 59mph to 68mph the 3.27 has the torque advantage.
From 68mph to 91mph the 3.77 has the torque advantage.
From 91mph to 105mph the 3.27 has the torque advantage.
From 105mph to 128mph the 3.77 has the torque advantage. (top speed reached for the 3.77)
From 128mph to 149mph the 3.27 has the torque and speed advantage.
So, if the race started at say 90mph the stock geared car would be significantly ahead of the 3.77 car at 105mph.
The 3.77 car should catch and likely pass the 3.27 car to 128mph and then of course the 3.27 car would run away from the speed limited 3.77 car.
The BEST part about the gear change is the FEEL of the car is snappy and quicker even though in actual timed performance the difference is minimal. Of course if you also recieved the torsen or LSD differential you should have an advantage off the line... unless the "stock" car has the "free" lsd mod
BTW, do not dismiss the FEEL component above as it makes driving much more fun and is certainly one of the reasons I talk about it so often with regards to exhaust mods.
Note: the stock ratio is 3.266 which rounds to 3.27. The Supra ratio is 3.769 which rounds to 3.77. Most will recognize 3.76. Another way to think about this would be 3.3 vs 3.8. The 3.3 multiplies the engine driveshaft torque by 3.3 times, and, you guessed it... the 3.8 multiplies the driveshaft torque by 3.8 times.The driveshaft is of course the tranny output and the transmission multiplies the engine torque by whatever gear is being used PLUS whatever the torque converter has multiplied. These numbers can get impressive and can be as high as 3000 pound feet at the wheels. Yes, I said 3000 pounds of torque AT the wheels.
The change in gearing gives MORE torque at the rear wheels in every gear at any give RPM. The TWIST is that with a hard rev limit of 6300rpm this improvement comes at a COST... As noted with the 3.77 ratio the car shifts out of 2nd gear at 59mph while with 3.27 ratio the same shift happens at 68mph. These numbers are calculated at 6150rpm which is realistically the highest consistent shift point without hitting the limiter.
Looking at the 1st to 2nd shift the respective speeds are 38mph and 44mph.
2nd to 3rd are 59mph and 68mph.
3rd to 4th are 91mph and 105mph.
4th to 5th are 129mph and 149mph.
What do these numbers mean for REAL world driving performance?
From 0mph to 38mph the 3.77 has the torque advantage.
From 38mph to 44mph the 3.27 has the torque advantage.
From 44mph to 59mph the 3.77 has the torque advantage.
From 59mph to 68mph the 3.27 has the torque advantage.
From 68mph to 91mph the 3.77 has the torque advantage.
From 91mph to 105mph the 3.27 has the torque advantage.
From 105mph to 128mph the 3.77 has the torque advantage. (top speed reached for the 3.77)
From 128mph to 149mph the 3.27 has the torque and speed advantage.
So, if the race started at say 90mph the stock geared car would be significantly ahead of the 3.77 car at 105mph.
The 3.77 car should catch and likely pass the 3.27 car to 128mph and then of course the 3.27 car would run away from the speed limited 3.77 car.
The BEST part about the gear change is the FEEL of the car is snappy and quicker even though in actual timed performance the difference is minimal. Of course if you also recieved the torsen or LSD differential you should have an advantage off the line... unless the "stock" car has the "free" lsd mod
BTW, do not dismiss the FEEL component above as it makes driving much more fun and is certainly one of the reasons I talk about it so often with regards to exhaust mods.
Note: the stock ratio is 3.266 which rounds to 3.27. The Supra ratio is 3.769 which rounds to 3.77. Most will recognize 3.76. Another way to think about this would be 3.3 vs 3.8. The 3.3 multiplies the engine driveshaft torque by 3.3 times, and, you guessed it... the 3.8 multiplies the driveshaft torque by 3.8 times.The driveshaft is of course the tranny output and the transmission multiplies the engine torque by whatever gear is being used PLUS whatever the torque converter has multiplied. These numbers can get impressive and can be as high as 3000 pound feet at the wheels. Yes, I said 3000 pounds of torque AT the wheels.
Also, as an aside...I messed around with a stockish GS4XX a long time ago when I just had an intake, exhaust, TC and the 3.73 LSD; we were on the highway so the TC didn't really do anything and let's put it this way it was NIGHT and DAY and he didn't EVER have a chance! This is a real world example, so with what you write things don't seem to be in-line with what I have experienced. Oh, and we are talking about automatics here so I don't want to hear, "perhaps he mis-shifted"
lol. I know you are a Lexus "purist" meaning you feel that it is impossible for a company to make better designs from OEM (such as with your OEM "Y" pipe threads; which THERE I happen to agree with you though) but IMHO the Supra LSD with the more aggressive gearing is just a better unit for the enthusiast; and since it came from a TT Supra I am sure it is a little more heavy duty than the stock GS diff aswell!
Point is there should be NO back and forth with, one has the torque advantage then the other now has the torque advantage now the other has the greater torque advantage. If something is multiplying the powersource 3.7 times versus 3.2 times then this will always remain constant. Different speeds shouldn't matter.
...and if you are talking technically, where the OEM diff has the torque advantage it is merely because one is either starting or coming to the end of their shift points and...OF COURSE then one will have the advantage over the other because the shift points are different.
For anyone thinking of buying this unit, I am telling you right now...unless you race a stock GS4XX from EXACTLY and ONLY the below mentioned 10MPH stints, then yes, it would be a very close race In this tiny window but who the hell does this?
From 38mph to 44mph the 3.27 has the torque advantage
From 59mph to 68mph the 3.27 has the torque advantage
From 91mph to 105mph the 3.27 has the torque advantage
If both hit WOT from 20, 30, 40, 50, 60, 70 or 80mph I assure you the car with the 3.73 LSD will blow the other car away. period. Oh, and when "torque advantage" is mentioned I WILL BET ANYTHING that it is not directly proportionate!
For example, let's say the 3.73 has the "torque advantage" given a certain speed interval as J mentions and it is producing 270wtq and in the SAME INTERVAL the 3.23 is producing 220wtq. Now, let's say the 3.26 has the "torque advantage" given a certain speed interval as J mentions and it is producing 250wtq and in the SAME INTERVAL the 3.73 is probably producing 240wtq. So, if you look at the above you will notice that when the 3.73 has the "torque advantage" it REALLY has a torque advantage (+50wtq) and when the 3.23 has the torque advantage it only has an advantage of say +10wtq. So, the NET EFFECT is during a TYPICAL roll race the car with the more aggressive gearing will prevail; no ands, ifs or buts about it. The ONLY down fall is yes, when the car with the more aggressive gearing reaches its MECHANICAL top speed limit...obviously the other car would pass it by; while the other is bouncing off the rev limiter.
Last edited by Rock-a-Lex; 02-08-11 at 06:26 AM.
02-08-11, 08:41 AM
#10
Lexus Champion
Rock,
First off I NEVER use the word impossible (except to say I never use it
)
With regards to improving upon OEM it is ALWAYS possible especially when the owners goals differ from the factory goals. Regarding Y pipes it is definitely possible... just MUCH harder than most imagine as MOST have a hard time understanding how a larger pipe can reduce performance.
Regarding your question(s)... rebut...
Here is how it works.
First of all many people do not realize that rwtq (rear wheel torque) is NOT what a dynojet reports. While a dynojet DOES report rwhp (rear wheel horsepower) the torque number is actually recalculated back to engine RPM. This makes for a more understandable number from an ENGINE performance standpoint because rwtq CHANGES with EVERY gear change the transmission makes.
For simplicity sake lets use ENGINE torque of 300 lb/ft.
For simplicity we will ignore the torque changes as RPM changes.
For simplicity sake we will not include the effect of the torque converter.
For simplicity sake we will not include drivetrain loss.
The engines torque is fed into the transmission.
First gear has a ratio of 3.357 to 1. The torque exiting the transmission has been multiplied and is now 3.357 x 300 = 1007 lb/ft
This 1007 lb/ft now is multiplied by the differential gearing. At 3.266 the torque to the wheels is now (3.266 x 1007) = 3289 rwtq
When the transmission shifts into 2nd gear with a ratio of 2.180 the WHEEL or RWTQ drops accordingly. 300 (engine) x 2.180 (trans 2nd gear) x 3.266 (diff) = 2136 rwtq
With a 3.769 ratio the two above numbers are 3796rwtq in 1st and 2465rwtq in 2nd gear.
BUT... with the 3.769 ratio and a 6150rpm shift point the car shifts into 2nd gear at... you guessed it... 38mph.
With the 3.266 ratio the car STAYS in 1st gear until... yup... 44mph.
So, at the gear change, at 38mph the 3.769 car has 2465rwtq
The 3.266 car at 38-44mph has the HIGHER 3289rwtq. An advantage of an impressive 824rwtq. Yes, 824rwtq MORE than the 3.769 car. This occurs again and again as the 3.769 car shifts earlier and earlier vs the 3.266 car.
You can't argue with the BIG deal...
Uhhh... wait a minute... does can't mean impossible...
First off I NEVER use the word impossible (except to say I never use it
)With regards to improving upon OEM it is ALWAYS possible especially when the owners goals differ from the factory goals. Regarding Y pipes it is definitely possible... just MUCH harder than most imagine as MOST have a hard time understanding how a larger pipe can reduce performance.
Regarding your question(s)... rebut...
Here is how it works.
First of all many people do not realize that rwtq (rear wheel torque) is NOT what a dynojet reports. While a dynojet DOES report rwhp (rear wheel horsepower) the torque number is actually recalculated back to engine RPM. This makes for a more understandable number from an ENGINE performance standpoint because rwtq CHANGES with EVERY gear change the transmission makes.
For simplicity sake lets use ENGINE torque of 300 lb/ft.
For simplicity we will ignore the torque changes as RPM changes.
For simplicity sake we will not include the effect of the torque converter.
For simplicity sake we will not include drivetrain loss.
The engines torque is fed into the transmission.
First gear has a ratio of 3.357 to 1. The torque exiting the transmission has been multiplied and is now 3.357 x 300 = 1007 lb/ft
This 1007 lb/ft now is multiplied by the differential gearing. At 3.266 the torque to the wheels is now (3.266 x 1007) = 3289 rwtq
When the transmission shifts into 2nd gear with a ratio of 2.180 the WHEEL or RWTQ drops accordingly. 300 (engine) x 2.180 (trans 2nd gear) x 3.266 (diff) = 2136 rwtq
With a 3.769 ratio the two above numbers are 3796rwtq in 1st and 2465rwtq in 2nd gear.
BUT... with the 3.769 ratio and a 6150rpm shift point the car shifts into 2nd gear at... you guessed it... 38mph.
With the 3.266 ratio the car STAYS in 1st gear until... yup... 44mph.
So, at the gear change, at 38mph the 3.769 car has 2465rwtq
The 3.266 car at 38-44mph has the HIGHER 3289rwtq. An advantage of an impressive 824rwtq. Yes, 824rwtq MORE than the 3.769 car. This occurs again and again as the 3.769 car shifts earlier and earlier vs the 3.266 car.
You can't argue with the BIG deal...
Uhhh... wait a minute... does can't mean impossible...
Last edited by JBrady; 02-08-11 at 08:45 AM.
02-08-11, 08:53 AM
#11
Forum Administrator
iTrader: (2)
The one negative thing that hasn't been mentioned here (and should be aware of if you're considering buying) is that some owners with the 3.76 gearing have complained about is hitting and bouncing off the rev limiter at wide open throttle after upgrading especially in the 1 - 2 shift.
It most certainly does not happen to everyone, but it does happen to some and you don't know until you have it in your car. Sometimes doing a valve body upgrade and using a good synthetic fluid (Amsoil) helped reduce the issue, sometimes it didn't.
The only other negative from this I've read about is loss of MPG. Higher RPM = more fuel and if this is your daily just know its going to cost you more at the pump.
It most certainly does not happen to everyone, but it does happen to some and you don't know until you have it in your car. Sometimes doing a valve body upgrade and using a good synthetic fluid (Amsoil) helped reduce the issue, sometimes it didn't.
The only other negative from this I've read about is loss of MPG. Higher RPM = more fuel and if this is your daily just know its going to cost you more at the pump.
02-08-11, 08:59 AM
#12
Lexus Champion
Regarding torque converters and HORSEPOWER. A decent amount of the loss in a drivetrain is related to inertia. Lighter parts take less POWER to accelerate and therefore have LESS impact on drivetrain loss. The larger the diameter the higher the leverage and impact weight will have on drivetrain loss. This is ONE great reason to use the LIGHTEST tire/wheel combination for performance as they take less power to accelerate leaving more power to move the vehicle.
I have not measured a Precision Industries torque converter but if it is smaller in diameter and/or lighter than the stock converter it WILL increase RWHP at any speed and in any gear even when in full lock mode.
This is just one of the differences that help explain surprising car performance. That said the very FIRST S&S header set went on a GS400 that had 3.769 gears. That particular car picked up the usual 15rwhp. Great right? Sure. Problem is when raced against a STOCK GS400 it LOST!!!
The "reason" was not proven one way or another as this was just one instance and was not repeated. I will say that some cars are STRONGER than others period. Even racing classes that use "spec" cars that are all built to the exact same "specs" end up with some cars that run "better" and some that run "slower". The reasons are too complicated for this post but include and are complicated further by our ECU action that can/does/will effect the real power the car will make. My LS400 went from 14.9 bone stock on my first track day down to 14.5 on my next time out with NO changes to the car except more agressive driving (causing the ECU to adapt). This is equivilant to 40rwhp. I was able to drop this to 14.22 with my airbox mod, 80 pounds less weight and 40 degrees cooler track temperature. This is the equivilant of 70rwhp difference.
I have not measured a Precision Industries torque converter but if it is smaller in diameter and/or lighter than the stock converter it WILL increase RWHP at any speed and in any gear even when in full lock mode.
This is just one of the differences that help explain surprising car performance. That said the very FIRST S&S header set went on a GS400 that had 3.769 gears. That particular car picked up the usual 15rwhp. Great right? Sure. Problem is when raced against a STOCK GS400 it LOST!!!
The "reason" was not proven one way or another as this was just one instance and was not repeated. I will say that some cars are STRONGER than others period. Even racing classes that use "spec" cars that are all built to the exact same "specs" end up with some cars that run "better" and some that run "slower". The reasons are too complicated for this post but include and are complicated further by our ECU action that can/does/will effect the real power the car will make. My LS400 went from 14.9 bone stock on my first track day down to 14.5 on my next time out with NO changes to the car except more agressive driving (causing the ECU to adapt). This is equivilant to 40rwhp. I was able to drop this to 14.22 with my airbox mod, 80 pounds less weight and 40 degrees cooler track temperature. This is the equivilant of 70rwhp difference.
02-08-11, 12:33 PM
#13
Regarding torque converters and HORSEPOWER. A decent amount of the loss in a drivetrain is related to inertia. Lighter parts take less POWER to accelerate and therefore have LESS impact on drivetrain loss. The larger the diameter the higher the leverage and impact weight will have on drivetrain loss. This is ONE great reason to use the LIGHTEST tire/wheel combination for performance as they take less power to accelerate leaving more power to move the vehicle.
I have not measured a Precision Industries torque converter but if it is smaller in diameter and/or lighter than the stock converter it WILL increase RWHP at any speed and in any gear even when in full lock mode.
This is just one of the differences that help explain surprising car performance. That said the very FIRST S&S header set went on a GS400 that had 3.769 gears. That particular car picked up the usual 15rwhp. Great right? Sure. Problem is when raced against a STOCK GS400 it LOST!!!
The "reason" was not proven one way or another as this was just one instance and was not repeated. I will say that some cars are STRONGER than others period. Even racing classes that use "spec" cars that are all built to the exact same "specs" end up with some cars that run "better" and some that run "slower". The reasons are too complicated for this post but include and are complicated further by our ECU action that can/does/will effect the real power the car will make. My LS400 went from 14.9 bone stock on my first track day down to 14.5 on my next time out with NO changes to the car except more agressive driving (causing the ECU to adapt). This is equivilant to 40rwhp. I was able to drop this to 14.22 with my airbox mod, 80 pounds less weight and 40 degrees cooler track temperature. This is the equivilant of 70rwhp difference.
I have not measured a Precision Industries torque converter but if it is smaller in diameter and/or lighter than the stock converter it WILL increase RWHP at any speed and in any gear even when in full lock mode.
This is just one of the differences that help explain surprising car performance. That said the very FIRST S&S header set went on a GS400 that had 3.769 gears. That particular car picked up the usual 15rwhp. Great right? Sure. Problem is when raced against a STOCK GS400 it LOST!!!
The "reason" was not proven one way or another as this was just one instance and was not repeated. I will say that some cars are STRONGER than others period. Even racing classes that use "spec" cars that are all built to the exact same "specs" end up with some cars that run "better" and some that run "slower". The reasons are too complicated for this post but include and are complicated further by our ECU action that can/does/will effect the real power the car will make. My LS400 went from 14.9 bone stock on my first track day down to 14.5 on my next time out with NO changes to the car except more agressive driving (causing the ECU to adapt). This is equivilant to 40rwhp. I was able to drop this to 14.22 with my airbox mod, 80 pounds less weight and 40 degrees cooler track temperature. This is the equivilant of 70rwhp difference.
Unfortunately, many like to mod there cars FIRST without making sure everything is properly maintained. Why do you think that I make the most power (or one of the most) on these boards for an NA setup (excluding Nitrous and Meth injection)? Many on here have the same mods as me and cannot deliver the same figures; and I'm sure their cars don't feel the same as mine...I really got to post up some videos for everyone. My dyno's weren't performed on the "pleasant" dynojet either; it was on a DynoDynamics AWD dyno (like a mustang dyno). People feel that although they show lower numbers they are a little more accurate than Dynojets.
Very good information you got there John as far as the gearing goes. So, your figures 1st gear the 3.73 gearing has 3796 rwtq and drops to 2465 rwtq in 2nd gear. Wheras, the 3.26 gearing has 3289 rwtq and drops to 2136 rwtq in 2nd gear. At some small, certain moments at gear changes, yes the 3.26 gearing is making more power. But just look at the differences between all the max rwtq numbers.
Throughout first gear, the 3.73 gearing made 500+ rwtq more than the 3.26 gearing BUT the 3.26 gearing still has room left on the tach when the 3.73 is shifting to 2nd gear.
Then, throughout second gear, the 3.73 gearing made 300+ rwtq more than the 3.26 gearing BUT the 3.26 gearing still has room left on the tach when the 3.73 is shifting to 3rd gear.
When everything is netted out, I am telling you on a normal roll race the 3.73 gearing provides greater acceleration eventhough it shifts sooner throughout each gear change.
I am still a firm believer that If I run someone with all the same mods as me (excluding the 3.73 gearing); I will come out on top.
We can agree to disagree...
06-27-11, 10:47 PM
#14
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Do they make less gear for the GS 430. lets say a 273:1. how did the 376 gear change inpact the speed0??? did it read a high reading on the dash than the car was travleing?
06-27-11, 11:20 PM
#15
They are talking about something else. I went with the stock gear on my LSD. I plan to reduce weight and add power. If you want a different gear, you would have to search around the internet. Maybe call up jawsgear for a lead.