My GS400 = 4.76 0-60mph! G-Tech RR
12-17-09, 03:21 PM
#31
I'm not questioning others' reliability, but the 1/4 mile times stated by others as having achieved in the past could needless to say be affected GREATLY by 20" steel wheels, slicks, temp, tuning, car condition, driving technique, etc. etc.
I bet a guy could dream up a circumstance where Rock's tuned, N/A car could keep up with a stock GS4 with a supercharger (maybe the FI car's belt is slipping, is only running 3-4psi, traction issues, heavy wheels, needs a tune-up/tuning, etc.)
My point is that I wouldn't give a CRAP what other's times are, I'd take 'er to the track. Can't argue with a timeslip.
I bet a guy could dream up a circumstance where Rock's tuned, N/A car could keep up with a stock GS4 with a supercharger (maybe the FI car's belt is slipping, is only running 3-4psi, traction issues, heavy wheels, needs a tune-up/tuning, etc.)
My point is that I wouldn't give a CRAP what other's times are, I'd take 'er to the track. Can't argue with a timeslip.
12-18-09, 10:00 AM
#32
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What gear are y'all running through the traps in for a 1/4 mile pass? What rpm? Just curious.
I think Dumped GS said that 3rd and 4th have long legs so the 4.08 would get you into each gear sooner if that would be a benefit, depends on power delivery related to rpm. On the flip side it will hurt your off the line traction that much more so DR would be more nec. Say the car is passing through the lights in 3rd now with a 3.76, but with a 4.08 it has to shift to 4th just before the lights then your car would likely be faster with the 3.76.
Someone mentioned the importance of gearing as it relates to power delivery, not peak power, but delivery and they are dead on.
For a better 1/4 time, if an IS350 has a better rear end ratio and better shift points based on its power delivery, and even similar power to weight ratio to a warmed over GS then it will be faster than the GS because of the unfavorable gearing on the GS, at least for 1/4 use. So even with less power, less torque, less area under the curve, if its similar, and the shift points are better matched, it would be the faster car for 1/4 use.
I think Dumped GS said that 3rd and 4th have long legs so the 4.08 would get you into each gear sooner if that would be a benefit, depends on power delivery related to rpm. On the flip side it will hurt your off the line traction that much more so DR would be more nec. Say the car is passing through the lights in 3rd now with a 3.76, but with a 4.08 it has to shift to 4th just before the lights then your car would likely be faster with the 3.76.
Someone mentioned the importance of gearing as it relates to power delivery, not peak power, but delivery and they are dead on.
For a better 1/4 time, if an IS350 has a better rear end ratio and better shift points based on its power delivery, and even similar power to weight ratio to a warmed over GS then it will be faster than the GS because of the unfavorable gearing on the GS, at least for 1/4 use. So even with less power, less torque, less area under the curve, if its similar, and the shift points are better matched, it would be the faster car for 1/4 use.
12-18-09, 12:04 PM
#33
Lexus Champion
What gear are y'all running through the traps in for a 1/4 mile pass? What rpm? Just curious.
I think Dumped GS said that 3rd and 4th have long legs so the 4.08 would get you into each gear sooner if that would be a benefit, depends on power delivery related to rpm. On the flip side it will hurt your off the line traction that much more so DR would be more nec. Say the car is passing through the lights in 3rd now with a 3.76, but with a 4.08 it has to shift to 4th just before the lights then your car would likely be faster with the 3.76.
Someone mentioned the importance of gearing as it relates to power delivery, not peak power, but delivery and they are dead on.
For a better 1/4 time, if an IS350 has a better rear end ratio and better shift points based on its power delivery, and even similar power to weight ratio to a warmed over GS then it will be faster than the GS because of the unfavorable gearing on the GS, at least for 1/4 use. So even with less power, less torque, less area under the curve, if its similar, and the shift points are better matched, it would be the faster car for 1/4 use.
I think Dumped GS said that 3rd and 4th have long legs so the 4.08 would get you into each gear sooner if that would be a benefit, depends on power delivery related to rpm. On the flip side it will hurt your off the line traction that much more so DR would be more nec. Say the car is passing through the lights in 3rd now with a 3.76, but with a 4.08 it has to shift to 4th just before the lights then your car would likely be faster with the 3.76.
Someone mentioned the importance of gearing as it relates to power delivery, not peak power, but delivery and they are dead on.
For a better 1/4 time, if an IS350 has a better rear end ratio and better shift points based on its power delivery, and even similar power to weight ratio to a warmed over GS then it will be faster than the GS because of the unfavorable gearing on the GS, at least for 1/4 use. So even with less power, less torque, less area under the curve, if its similar, and the shift points are better matched, it would be the faster car for 1/4 use.
Stock redline on these engines is 6300rpm and the tranny generally shifts early. If you hold it in gear you can get closer IF you shift soon enough to not hit the rev limiter which is tricky. The engine also gets torque pulled prior to shifting. I have not driven the IS350 but the reports are that the tranny shifts fairly crisply whereas the 5 speed cars do not. The IS350 also looks to have a 6600rpm redline which is another benefit and peak power at 6400rpm. This allows staying in a lower gear longer taking more advantage of the torque multiplication.
Here are the multiplied gear ratios tranny times final:
GS4xx ------ IS350
1st: 10.96-----14.36
2nd: 7.12-----8.32
3rd: 4.65-----5.71
4th: 3.26-----4.08
5th: 2.46-----2.94
Last edited by JBrady; 12-18-09 at 06:43 PM.
12-18-09, 12:05 PM
#34
Just curious at a probable 1/4 mile trap of 100mph - 104mph would a GS4 be in the same gear with the stock 3.23 gears versus the 3.76 Supra TT gears? If so then to the 1/4 mile it will benefit because it will be more into the gear at those speeds.
However, I can see how the 0-60 times would suffer with the 3.76 gears because they make the GS4 shift to 3rd exactly at 58mph (like many have mentioned previously). So maybe from 0-58 it would be faster than a GS4 with the stock 3.23 gears but to 60mph with that extra shift would/could lose close to .4 seconds.
It's obvious that the extra shift to 60mph hurts the 0-60 but does the addition of the 3.76 gearing ALSO hurt 1/4 mile times? Or at that speed it wouldn't matter anyway because you would be in the same gear by then with either rear end?
However, I can see how the 0-60 times would suffer with the 3.76 gears because they make the GS4 shift to 3rd exactly at 58mph (like many have mentioned previously). So maybe from 0-58 it would be faster than a GS4 with the stock 3.23 gears but to 60mph with that extra shift would/could lose close to .4 seconds.
It's obvious that the extra shift to 60mph hurts the 0-60 but does the addition of the 3.76 gearing ALSO hurt 1/4 mile times? Or at that speed it wouldn't matter anyway because you would be in the same gear by then with either rear end?
12-18-09, 12:42 PM
#35
From what I can remember that I have read on the forum, is that the higher rear end (3.76) gearing does not improve 1/4 mile times. Something to do with the transmission not shifting at the optimum RPM any longer. The Butt DYno will feel it.
Can someone chime in?
Can someone chime in?
Last edited by GSJake; 12-18-09 at 05:03 PM.
12-18-09, 04:01 PM
#36
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Its interesting to note that I have seen that the guys that are getting the best times in the IS350s are doing it with the trans in normal mode, not ect, and not shifting it themselves.
12-21-09, 08:54 AM
#37
i got the same 1/4 time shifting myself (e-shift) and leaving the car in drive wtih pwr mode on. my car did however slow down with leaving the trans in its normal mode. it was only a couple tenths though (dont remember exactly) i wish someone made an aftermarket trans ecu....i still say thats the limiting factor in making our cars go faster.
12-21-09, 09:46 AM
#38
Lexus Champion
i got the same 1/4 time shifting myself (e-shift) and leaving the car in drive wtih pwr mode on. my car did however slow down with leaving the trans in its normal mode. it was only a couple tenths though (dont remember exactly) i wish someone made an aftermarket trans ecu....i still say thats the limiting factor in making our cars go faster.
12-22-09, 08:22 AM
#39
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I also got the fastest 1/4 times running in drive in power mode letting it shift itself. I also wish for a trans ecu. I like the factory programming for less than full throttle performance but would prefer rapid full throttle shifts without the ignition retard. I would like to see what these cars would do under these conditions with 6500rpm shifts (would require engine ecu changes). Makes me jealous that the Corvette guys can modify the factory ecu to their liking and we cannot change anything
12-22-09, 09:39 AM
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Dyno sheets are another excellent piece of data that can be used to determine shift points as well. This is one from my car:
99 GS4
SRT intake/wiring
Magnaflow replacement rear mufflers only
stock wheels/tires
99 GS4
SRT intake/wiring
Magnaflow replacement rear mufflers only
stock wheels/tires
12-23-09, 05:14 AM
#41
Well, I'm really not good at "reading" dyno charts.
I am going to get re-tuned as the shop has tuned only 2 gs' before....Mine last year (the first time) and CL member clivej.
What do you guys think of my latest run in April? How do the curves look?
I am going to get re-tuned as the shop has tuned only 2 gs' before....Mine last year (the first time) and CL member clivej.
What do you guys think of my latest run in April? How do the curves look?
12-23-09, 08:19 AM
#42
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Your car would absolutely Goldberg tackle mine.
You can really see the flare of the converter there too.What rpm does it fall back to on gear change?
Now I need to do a search on how to lock this thing in a gear to see my numbers at lower rpms.
12-23-09, 09:11 AM
#43
Lexus Champion
Do you have a sheet with your AFR on it?
Your car would absolutely Goldberg tackle mine. You can really see the flare of the converter there too.
What rpm does it fall back to on gear change?
Now I need to do a search on how to lock this thing in a gear to see my numbers at lower rpms.
Your car would absolutely Goldberg tackle mine.
You can really see the flare of the converter there too.What rpm does it fall back to on gear change?
Now I need to do a search on how to lock this thing in a gear to see my numbers at lower rpms.
Regarding Rocks dyno sheet; VERY strong. Interesting that he gets that much torque at 3300rpm because his torque converter is supposed to stall at 2900 and should no longer show a big gain above stall.
ROCK, do you have a baseline dyno of the car in stock condition? Other stages of upgrade? I know you did pre-header runs and pre-tuning.
I haven't dyno'd my car and would also like to know any tricks for getting readings at the lowest possible RPM.
12-23-09, 12:29 PM
#44
In answer to your previous question: yes, I definitely drove it aggressively in the days before the runs. It does make a difference. I always leave the tranny in power mode but shift points still vary. If I have been driving slowly for a couple days or more and then go full throttle the car takes longer to respond to the throttle imput as well as runs slower and shifts sooner. The opposite is also the case.
Regarding Rocks dyno sheet; VERY strong. Interesting that he gets that much torque at 3300rpm because his torque converter is supposed to stall at 2900 and should no longer show a big gain above stall.
ROCK, do you have a baseline dyno of the car in stock condition? Other stages of upgrade? I know you did pre-header runs and pre-tuning.
I haven't dyno'd my car and would also like to know any tricks for getting readings at the lowest possible RPM.
Regarding Rocks dyno sheet; VERY strong. Interesting that he gets that much torque at 3300rpm because his torque converter is supposed to stall at 2900 and should no longer show a big gain above stall.
ROCK, do you have a baseline dyno of the car in stock condition? Other stages of upgrade? I know you did pre-header runs and pre-tuning.
I haven't dyno'd my car and would also like to know any tricks for getting readings at the lowest possible RPM.
No baseline dyno available but I have attached my 2/2/08 dyno for your review. It is when I had the TM spark plugs, K&N FIPK intake, Borla exhaust and the Apexi Neo. I ALSO had the high stall torque converter and 3.76 gears at this time as well. I think the tuner mentioned I was somewhere in the mid 240's as far as WHP goes before the tuning started (where the Neo was completely disconnected). I remember him saying that when they connected the Neo and tuned it to my mods I gained around 18whp and around 25wtq.
4/11/09. Then when I added the headers and had the neo re-tuned it produced ~282whp and ~306wtq.
12-23-09, 01:29 PM
#45
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In answer to your previous question: yes, I definitely drove it aggressively in the days before the runs. It does make a difference. I always leave the tranny in power mode but shift points still vary. If I have been driving slowly for a couple days or more and then go full throttle the car takes longer to respond to the throttle imput as well as runs slower and shifts sooner. The opposite is also the case.
Regarding Rocks dyno sheet; VERY strong. Interesting that he gets that much torque at 3300rpm because his torque converter is supposed to stall at 2900 and should no longer show a big gain above stall.
ROCK, do you have a baseline dyno of the car in stock condition? Other stages of upgrade? I know you did pre-header runs and pre-tuning.
I haven't dyno'd my car and would also like to know any tricks for getting readings at the lowest possible RPM.
Regarding Rocks dyno sheet; VERY strong. Interesting that he gets that much torque at 3300rpm because his torque converter is supposed to stall at 2900 and should no longer show a big gain above stall.
ROCK, do you have a baseline dyno of the car in stock condition? Other stages of upgrade? I know you did pre-header runs and pre-tuning.
I haven't dyno'd my car and would also like to know any tricks for getting readings at the lowest possible RPM.