Gears or more boost?
Thread Starter
Banned Scam/Spammer
Joined: Apr 2020
Posts: 322
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Gears or more boost?
My current mods on my 03 base are:
TSP longtubes (catless)
Corsa Indys
ECS 1500 base kit with included blower pulley
Tuned by Doug at ECS
550 whp / 487 wtq
The car runs great, but i wish it could get into the powerband much quicker from a roll. I want everyone's opinion on what to do. Should i put 3.73 or 3.90 gears in it? Or should i pulley down, add meth and add more boost? Gaining power is not a primary concern, i just want it to get moving faster from a roll. Im currently not having any issues with traction due to the tune, my driving style (i dont mash it, i squeeze it) and my tires. Im running Nitto NT 05s. Great tires. My gut is saying gears but i wouldnt know what set to pick.
If it were your car, what exactly would you do??
Thanks.
TSP longtubes (catless)
Corsa Indys
ECS 1500 base kit with included blower pulley
Tuned by Doug at ECS
550 whp / 487 wtq
The car runs great, but i wish it could get into the powerband much quicker from a roll. I want everyone's opinion on what to do. Should i put 3.73 or 3.90 gears in it? Or should i pulley down, add meth and add more boost? Gaining power is not a primary concern, i just want it to get moving faster from a roll. Im currently not having any issues with traction due to the tune, my driving style (i dont mash it, i squeeze it) and my tires. Im running Nitto NT 05s. Great tires. My gut is saying gears but i wouldnt know what set to pick.
If it were your car, what exactly would you do??
Thanks.
Safety Car
Joined: Oct 2007
Posts: 4,204
Likes: 1,074
From: South Florida
The lower the gear ratio numerically, the faster the vehicle capability, the better it can utilize high end horsepower and top speed it will have
I would never increase the gear ratio numerical in your position. always add power, not gear. Gearing is for making up for lack of power.
I would never increase the gear ratio numerical in your position. always add power, not gear. Gearing is for making up for lack of power.
Intermediate
Joined: Nov 2015
Posts: 48
Likes: 26
I think going with gears would perfectly solve your issues. Years ago, I had a 2009 GT500 with a twin screw Whipple set up making 700 hp at the wheels. That car was heavy. I had the exact same complaints as you regarding off the line performance. I put in lower gears and it really transformed the car. It accomplished everything I wanted it to. Not too expensive either.
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
Id go with the gear as well. If youe engine is running well with your mods, I'd leave it alone. Your gear swap will put you in a better gear band ratio damn near instantaneously. This is a true SOTP improvement.
Melting Slicks
Joined: Dec 2004
Posts: 2,847
Likes: 1,144
From: Sleepy Hollow- NJ
My current mods on my 03 base are:
TSP longtubes (catless)
Corsa Indys
ECS 1500 base kit with included blower pulley
Tuned by Doug at ECS
550 whp / 487 wtq
The car runs great, but i wish it could get into the powerband much quicker from a roll. I want everyone's opinion on what to do. Should i put 3.73 or 3.90 gears in it? Or should i pulley down, add meth and add more boost? Gaining power is not a primary concern, i just want it to get moving faster from a roll. Im currently not having any issues with traction due to the tune, my driving style (i dont mash it, i squeeze it) and my tires. Im running Nitto NT 05s. Great tires. My gut is saying gears but i wouldnt know what set to pick.
If it were your car, what exactly would you do??
Thanks.
TSP longtubes (catless)
Corsa Indys
ECS 1500 base kit with included blower pulley
Tuned by Doug at ECS
550 whp / 487 wtq
The car runs great, but i wish it could get into the powerband much quicker from a roll. I want everyone's opinion on what to do. Should i put 3.73 or 3.90 gears in it? Or should i pulley down, add meth and add more boost? Gaining power is not a primary concern, i just want it to get moving faster from a roll. Im currently not having any issues with traction due to the tune, my driving style (i dont mash it, i squeeze it) and my tires. Im running Nitto NT 05s. Great tires. My gut is saying gears but i wouldnt know what set to pick.
If it were your car, what exactly would you do??
Thanks.
Yet I miss the responsiveness the 4.10 gear provided. Especially at low and midrange driving speeds. HOWEVER, when I jump into the gas with the current power I'm through the gears with the 3.42s really quickly.
I debate going with a 3.90 as this is the equivelant of an M12 with 3.42s. Which guys running procharged Z06's rarely ever complain about not having enough gear. The 3.73 in my opinion isn't enough gear to make the transition from 3.42s.
Safety Car
Joined: Jul 2010
Posts: 3,950
Likes: 386
From: Chandler AZ
My current mods on my 03 base are:
TSP longtubes (catless)
Corsa Indys
ECS 1500 base kit with included blower pulley
Tuned by Doug at ECS
550 whp / 487 wtq
The car runs great, but i wish it could get into the powerband much quicker from a roll. I want everyone's opinion on what to do. Should i put 3.73 or 3.90 gears in it? Or should i pulley down, add meth and add more boost? Gaining power is not a primary concern, i just want it to get moving faster from a roll. Im currently not having any issues with traction due to the tune, my driving style (i dont mash it, i squeeze it) and my tires. Im running Nitto NT 05s. Great tires. My gut is saying gears but i wouldnt know what set to pick.
If it were your car, what exactly would you do??
Thanks.
TSP longtubes (catless)
Corsa Indys
ECS 1500 base kit with included blower pulley
Tuned by Doug at ECS
550 whp / 487 wtq
The car runs great, but i wish it could get into the powerband much quicker from a roll. I want everyone's opinion on what to do. Should i put 3.73 or 3.90 gears in it? Or should i pulley down, add meth and add more boost? Gaining power is not a primary concern, i just want it to get moving faster from a roll. Im currently not having any issues with traction due to the tune, my driving style (i dont mash it, i squeeze it) and my tires. Im running Nitto NT 05s. Great tires. My gut is saying gears but i wouldnt know what set to pick.
If it were your car, what exactly would you do??
Thanks.
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Pro
Joined: Oct 2020
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From: Columbus, MS
What have you done with the suspension? Your better move for overall speed may be to be able to better put the power down through the rear wheels. If you're still on stock suspension it might be worth looking into upgrading that before adding more power
Thread Starter
Banned Scam/Spammer
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I'm contemplating the same decision. I ran a 4.10 gear for many years in my last H/C/I build. I blew the diff at Island Dragway and swapped my 3.42 diff back in. I then procharged that H/C/I build with 3.42s. My car makes 634rwhp/568rwtq.
Yet I miss the responsiveness the 4.10 gear provided. Especially at low and midrange driving speeds. HOWEVER, when I jump into the gas with the current power I'm through the gears with the 3.42s really quickly.
I debate going with a 3.90 as this is the equivelant of an M12 with 3.42s. Which guys running procharged Z06's rarely ever complain about not having enough gear. The 3.73 in my opinion isn't enough gear to make the transition from 3.42s.
Yet I miss the responsiveness the 4.10 gear provided. Especially at low and midrange driving speeds. HOWEVER, when I jump into the gas with the current power I'm through the gears with the 3.42s really quickly.
I debate going with a 3.90 as this is the equivelant of an M12 with 3.42s. Which guys running procharged Z06's rarely ever complain about not having enough gear. The 3.73 in my opinion isn't enough gear to make the transition from 3.42s.
Last edited by 2003_Coupe; Jul 31, 2022 at 03:44 PM.
Thread Starter
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Melting Slicks
Joined: Dec 2004
Posts: 2,847
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From: Sleepy Hollow- NJ
Thread Starter
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As long as you dont launch the car the diff will be perfectly fine and happy. If you want to abuse it there is always the option to rebuild the internals and output shafts with beefier parts. If i ended up changing the ring and pinion i would do that while i was in there anyway. It all comes down to how you want to drive it.
Melting Slicks
Joined: Dec 2004
Posts: 2,847
Likes: 1,144
From: Sleepy Hollow- NJ
It's the long legs of the 3.42 that doesn't help. I forgot how much I hated the 3.42s until I swapped the diff back in. My cam loves a steep gear. With the procharger lag it seems it wants it even more when just moderately getting in the gas. Especially when doing small rips in the car. But when I dump the throttle I'm blowing through gears mighty quick.
So it's the trade off of having less lag under moderately spirited driving conditions but dealing with the gears going by even faster under WOT.
That's what has got me on the fence.
Thread Starter
Banned Scam/Spammer
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Agreed. It's all a trade off. It's that slight lag that you are trying to reduce. I'm with you on that.
It's the long legs of the 3.42 that doesn't help. I forgot how much I hated the 3.42s until I swapped the diff back in. My cam loves a steep gear. With the procharger lag it seems it wants it even more when just moderately getting in the gas. Especially when doing small rips in the car. But when I dump the throttle I'm blowing through gears mighty quick.
So it's the trade off of having less lag under moderately spirited driving conditions but dealing with the gears going by even faster under WOT.
That's what has got me on the fence.
It's the long legs of the 3.42 that doesn't help. I forgot how much I hated the 3.42s until I swapped the diff back in. My cam loves a steep gear. With the procharger lag it seems it wants it even more when just moderately getting in the gas. Especially when doing small rips in the car. But when I dump the throttle I'm blowing through gears mighty quick.
So it's the trade off of having less lag under moderately spirited driving conditions but dealing with the gears going by even faster under WOT.
That's what has got me on the fence.
Le Mans Master
Joined: Nov 2003
Posts: 8,003
Likes: 249
From: Tampa Fl
St. Jude Donor '12-'13-'14
Assuming your a manual, adding 3.90 gears will feel like you adding 50 RWHP with no downside. You wont need an updated tune for the speedo, but with your power you'd probably want the tune scanned just to make sure your AFR numbers fall into place.
Melting Slicks
Joined: Dec 2004
Posts: 2,847
Likes: 1,144
From: Sleepy Hollow- NJ
I've run the 3.90s in a mostly stock NA C5. I've run the 4.10s in an H/C/I set up. The 4.10s (IMO) are a better gear. Especially in the 425rwhp or less range. The 3.73 isn't enough of a change from 3.42. Sooo...3.90 final answer!
Of course I can just remind myself to drive it more often. And when I do drive it...down shift more to get it into the powerband quicker vs. doing a rolling stab at low RPM and complaining about lag.
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3.90 is the route I'll go when I decide it's time. As mentioned above its pretty much like for like to the M12 equipped Z06. So I think it will be the sweet spot with my procharged MN6.
I've run the 3.90s in a mostly stock NA C5. I've run the 4.10s in an H/C/I set up. The 4.10s (IMO) are a better gear. Especially in the 425rwhp or less range. The 3.73 isn't enough of a change from 3.42. Sooo...3.90 final answer!
Of course I can just remind myself to drive it more often. And when I do drive it...down shift more to get it into the powerband quicker vs. doing a rolling stab at low RPM and complaining about lag.
I've run the 3.90s in a mostly stock NA C5. I've run the 4.10s in an H/C/I set up. The 4.10s (IMO) are a better gear. Especially in the 425rwhp or less range. The 3.73 isn't enough of a change from 3.42. Sooo...3.90 final answer!
Of course I can just remind myself to drive it more often. And when I do drive it...down shift more to get it into the powerband quicker vs. doing a rolling stab at low RPM and complaining about lag.
Race Director
Joined: Mar 2004
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From: Fort Wayne IN
2025 C5 of the Year Finalist - Modified
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At your power level, boost. Adding steeper gears will inevitably cause traction issues, even with the linear blower powerband.
Le Mans Master
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I wish I had traction issues!
With the 3.90s you’re multiplying wheel torque by ~15%, which may affect your traction. It sure as hell will increase the fun factor!
Another way to look at it is less stress on the engine and transmission, since the rear end is using a longer lever to lift the rock, so to speak. If you want quicker revs and more snap off the throttle, these gears will deliver. Even on a stock engine the 3.90s match up well to typical posted speeds, and even in the freeways. These should have come on the car to begin with…
With the 3.90s you’re multiplying wheel torque by ~15%, which may affect your traction. It sure as hell will increase the fun factor!
Another way to look at it is less stress on the engine and transmission, since the rear end is using a longer lever to lift the rock, so to speak. If you want quicker revs and more snap off the throttle, these gears will deliver. Even on a stock engine the 3.90s match up well to typical posted speeds, and even in the freeways. These should have come on the car to begin with…