Different gears for HPDE?
#1
Burning Brakes
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St. Jude Donor '15
Different gears for HPDE?
After reading various threads on gears, 410's seem to be preferred...but they always seem to be relevant to drag racing.
I only have been to HPDEs and will continue to do so. Recently, the car has developed a really loud whirring sound and I'm convinced it is from the gears. Driving the car hard has likely worn down the gears significantly. I'm having it checked soon to confirm.
While I'm at it...I figured this may be a good time to switch gear ratios if I have to replace them anyway, but only if there's a benefit.
Essentially, I'm looking to take advantage of the max torque...which for my car doesn't start till about 3K RPM. Since' I'm still an intermediate driver and need more seat time, I'm wanting to know if changing the gears out will help with acceleration. Since I am losing momentum too much sometimes, different gears may be a helpful crutch for me to get back up to speed quickly on the exits.
I firmly believe that simply having more seat time and learning the car/track will drastically help in the long run, but if gears give me a little bump while I'm still learning...I'd like to make that mod.
So, will a gear change help me? Which gears should I go to?
I only have been to HPDEs and will continue to do so. Recently, the car has developed a really loud whirring sound and I'm convinced it is from the gears. Driving the car hard has likely worn down the gears significantly. I'm having it checked soon to confirm.
While I'm at it...I figured this may be a good time to switch gear ratios if I have to replace them anyway, but only if there's a benefit.
Essentially, I'm looking to take advantage of the max torque...which for my car doesn't start till about 3K RPM. Since' I'm still an intermediate driver and need more seat time, I'm wanting to know if changing the gears out will help with acceleration. Since I am losing momentum too much sometimes, different gears may be a helpful crutch for me to get back up to speed quickly on the exits.
I firmly believe that simply having more seat time and learning the car/track will drastically help in the long run, but if gears give me a little bump while I'm still learning...I'd like to make that mod.
So, will a gear change help me? Which gears should I go to?
#2
Safety Car
Changing to lower gears is a two edged sword. Yes, it will give you more torque in the gear you select. However, you're probably going to find a lot of instances where you will run out of RPMs with the lower gears at just the wrong times. You redline and it's still 500 ft to the shut down markers so suddenly your choice it to upshift and then have to make a double downshift for the corner or just maintain redline for another 500 ft while the guy with the higher gears goes past you. As you get faster I think you will find the stock gear ratio will work pretty well for you.
#3
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It depends on the track you are running on but overall I doubt changing gears will help all that much. They will also increase the oil temp since you will be running the engine at higher rpms for longer periods of time. There is only so much torque that can be applied to the rear tires as you accelerate off an apex. If you aren't using Wide Open Throttle in the gear you currently select to do that then going to a higher gear ratio for increased torque will not provide any benefit.
I know people with C5Zs that went with 3:73 rear gears since that made 5th gear usable on long tracks. Without the 3:73s the engine wasn't in the proper rpm range to continue to accelerate strongly in 5th after a shift from 4th.
Bill
I know people with C5Zs that went with 3:73 rear gears since that made 5th gear usable on long tracks. Without the 3:73s the engine wasn't in the proper rpm range to continue to accelerate strongly in 5th after a shift from 4th.
Bill
#4
Burning Brakes
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St. Jude Donor '15
Hmm, OK guys thanks!
It sounds like there is no sure fire guarantee that it will improve my performance on the track. I'm not going to bother if it's not a definite upgrade that will give me what I'm looking for. Looks like I'll just need to be patient and improve myself to get what I want.
FYI: I did recently install an oil cooler because of on track oil temps. They were right at 2905ish...now they're down to 250 or so when I'm hitting it hard. It cools down quickly when I'm off it and back to 210 during the cool down lap.
It sounds like there is no sure fire guarantee that it will improve my performance on the track. I'm not going to bother if it's not a definite upgrade that will give me what I'm looking for. Looks like I'll just need to be patient and improve myself to get what I want.
FYI: I did recently install an oil cooler because of on track oil temps. They were right at 2905ish...now they're down to 250 or so when I'm hitting it hard. It cools down quickly when I'm off it and back to 210 during the cool down lap.
#5
Le Mans Master
I would think your current/ planned hp would be a big factor. I mean if you are running big tracks with only 330 rwhp the acceleration improvement might be very significant.
If you run 430+ hp however, it would seem to be pretty hard to put down any more power.
Good Luck!
If you run 430+ hp however, it would seem to be pretty hard to put down any more power.
Good Luck!
#6
Melting Slicks
Hmm, OK guys thanks!
It sounds like there is no sure fire guarantee that it will improve my performance on the track. I'm not going to bother if it's not a definite upgrade that will give me what I'm looking for. Looks like I'll just need to be patient and improve myself to get what I want.
It sounds like there is no sure fire guarantee that it will improve my performance on the track. I'm not going to bother if it's not a definite upgrade that will give me what I'm looking for. Looks like I'll just need to be patient and improve myself to get what I want.
You've just made the best possible and correct decision.
+ what Bill Dearborn said.
#7
Burning Brakes
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St. Jude Donor '15
I would think your current/ planned hp would be a big factor. I mean if you are running big tracks with only 330 rwhp the acceleration improvement might be very significant.
If you run 430+ hp however, it would seem to be pretty hard to put down any more power.
Good Luck!
If you run 430+ hp however, it would seem to be pretty hard to put down any more power.
Good Luck!
Agreed. In retrospect, I wish I would have never installed the supercharger and instead left if NA this early. The heat management is a lot to deal with and the extra power really isn't being used at my skill level. My single hope is to catch up to my car's capabilities in the next couple of years.
#8
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St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13
You need to figure out what you are going to see for approx top speeds at the tracks you run.
From there figure out what each gear is going to do for you.
Like they said above, you don't want to make it so you just have to hit a gear before a turn because you gained more RPM, but at the same time if you can get more gear advantage do so.
Remember a diff swap isn't going to change your splits just the max mph per gear...and a lot of people forget that when doing a swap.
A trans gear swap generally will do more for lap times by cutting down the drops between gears.
From there figure out what each gear is going to do for you.
Like they said above, you don't want to make it so you just have to hit a gear before a turn because you gained more RPM, but at the same time if you can get more gear advantage do so.
Remember a diff swap isn't going to change your splits just the max mph per gear...and a lot of people forget that when doing a swap.
A trans gear swap generally will do more for lap times by cutting down the drops between gears.
#9
Racer
BigMonkey37 here's a link that might help you out. You input the rear end ratio and trans ratio and it should give you a the MPH for given rpm.
I'd recommend you collect car/driver data before making any changes. You my want to try going thru the turns in a different gear to see if that might help, but with +500hp that could be hard to control coming out of a turn.
http://fitbodyshop.net/gear/index.php
I'd recommend you collect car/driver data before making any changes. You my want to try going thru the turns in a different gear to see if that might help, but with +500hp that could be hard to control coming out of a turn.
http://fitbodyshop.net/gear/index.php
#10
Le Mans Master
It's supercharged at 527RWHP right now. I have plenty of power, but don't know how to use it fully yet. I was hoping the gears would let me take advantage of more of that power....but it would seem skill is what I'm lacking...not more mechanical crutches.
Agreed. In retrospect, I wish I would have never installed the supercharger and instead left if NA this early. The heat management is a lot to deal with and the extra power really isn't being used at my skill level. My single hope is to catch up to my car's capabilities in the next couple of years.
Agreed. In retrospect, I wish I would have never installed the supercharger and instead left if NA this early. The heat management is a lot to deal with and the extra power really isn't being used at my skill level. My single hope is to catch up to my car's capabilities in the next couple of years.
On a 130 hp Miata, the net gain in speed offsets the slight loss of tractability exiting turns, but in a 400+ rwhp car, it seems to create more issues than it solves.
#11
Burning Brakes
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St. Jude Donor '15
I'm slowly leaning towards agreeing with you. If I had to start over, I'd have a dedicated '99 M3 as a track car and enjoy the Vette as my DD without some of the performance upgrades I've done to it.
I wish I had a track mentor before I jumped in with both feet!
I wish I had a track mentor before I jumped in with both feet!
#12
Drifting
To be honest, a 3:27 or even 3:08 gear would do you more good than a 4:10. It would help calm down the blower and make the power more manageable instead of coming on like a freight train.
#13
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This question really should consider the profile of your camshaft and which track is your favorite. I have a large cam that hits the rev limiter way before T5 at Putnam with the OEM C5Z tranny. A regular C5 tranny is better on that stretch. But, at the NCM MSP I find the C5Z tranny (different ratios) works better. Having tried both I am now back to the OEM C5Z tranny ratios. You may also consider short shifting on some portions of the track where RPM runs out. Even though the engine may feel like it wants more RPM you may find the torque gets you there quicker on those stretches.