NEWB Here.. NOT your typical 4.10 scenario question

oldyella · May 8, 2020

Hello all! I have an '05 GT 'Vert with factory 3.55 gears. I was debating between 3.73 and 4.10 ONLY because I have a lightweight flywheel, and 1'st gear is a tad on the short side now.
(I wish I would have stuck with OEM)

With that said, my only concern would be a virtual, non-existent 1st with the bigger gear and light flywheel combo. If I had the factory flywheel, this would be a no-brainer and there would be no debate in my head.

Tell me I'm just over reacting and that I should go with the 4.10's like I want to?
Any thoughts?

stkjock · May 8, 2020

Don’t be a pussy. 4.10s proven over and over again if you search you’ll see this question over and over

I had 4.10s a shorter tire and a blower

RED09GT · May 8, 2020

Why are you afraid of 1st gear being too short?
I switched back to 3.55's in my turbo car and hated it. The 4.10's went back in and I am much happier.
Don't fear the gear.

oldyella · May 8, 2020

stkjock said:
Don’t be a pussy.

LOL.. Speaking my language :beerchug3:

I guess I should add this is my daily driver. Not sure if that makes much of a difference in the decision making process or not.

RED09GT · May 8, 2020

Even on a daily driver.
4.10's should have been the factory gear on these cars. Driveability is better as well as the engine isn't under as much load to move the car.

stkjock · May 9, 2020

oldyella said:
LOL.. Speaking my language I guess I should add this is my daily driver. Not sure if that makes much of a difference in the decision making process or not.

My $.02, unless your concerned with fuel mileage, driving 100+ miles a day, or you’re a pussy, it doesn’t :cheers:

06 T-RED S/C GT · May 9, 2020

Only reason for switching back to 3:55 from 4:10 gears was for the amount of highway driving per day during car cruise season, as fuel mileage is the main concern along with running at lower RPM speeds when in 5th gear on the highway. Anyhow, if neither is a factor? then it doesn't really matter IMHO.

Norm Peterson · May 9, 2020

oldyella said:
Hello all! I have an '05 GT 'Vert with factory 3.55 gears. I was debating between 3.73 and 4.10 ONLY because I have a lightweight flywheel, and 1'st gear is a tad on the short side now.
(I wish I would have stuck with OEM)

With that said, my only concern would be a virtual, non-existent 1st with the bigger gear and light flywheel combo. If I had the factory flywheel, this would be a no-brainer and there would be no debate in my head.

Tell me I'm just over reacting and that I should go with the 4.10's like I want to?
Any thoughts?

Devil's advocate here . . .

4.10's would make getting your car rolling from a dead stop easier on the clutch given your light flywheel (the deeper axle gearing covering for the flywheel not being able to store as much energy of rotation as the OE wheel), But you'd clearly be in for some re-learning as far as normal street driving shift points are concerned.

Every gear will rev up quicker, and it may be tough at first to do what will feel like "short-shifting", and situations where you pull out into 45+ mph traffic from a side road and you're having to shift while you're going 15 - 20 mph slower than traffic will be a bit more stressful. You'll get to your (lower) shift speed sooner, but the 1-2 shift time now occurring at a lower speed will have traffic getting bigger in your mirrors faster than it used to.

For street driving, gearing in the TR3650 really isn't all that great. As you already know, 1st is shorter than necessary, even with 3.55's (I'm going to remind the drag strip crowd that we're not concerned with short times or ETs at all). Which manages to make 2nd too far away from 1st, with the engine either being wound out more than necessary in 1st or the transmission short-shifted.

Norm

GlassTop09 · May 9, 2020

oldyella said:
Hello all! I have an '05 GT 'Vert with factory 3.55 gears. I was debating between 3.73 and 4.10 ONLY because I have a lightweight flywheel, and 1'st gear is a tad on the short side now.
(I wish I would have stuck with OEM)

With that said, my only concern would be a virtual, non-existent 1st with the bigger gear and light flywheel combo. If I had the factory flywheel, this would be a no-brainer and there would be no debate in my head.

Tell me I'm just over reacting and that I should go with the 4.10's like I want to?
Any thoughts?

Ok OP, I think I understand what you are thinking here.....your right & are on the right track. 3.73 or 4.10 gears will help since you've switched to a lighter weight flywheel. Is your installed flywheel a lightened CM steel flywheel or is it an aluminum flywheel? If it is aluminum then you really need to swap to 4.10 gears but if it is a lightened CM steel flywheel then 3.73 or 4.10 gears will work. Most lightweight CM steel flywheels are around 15-16 lbs (aluminum is around 10-12 lbs) vs the OEM nodular iron flywheel at 22 lbs (actual weight as I've weighed mine myself & verified this) so you're giving up some "torque" from loss of spinning flywheel mass inertia to move car off in 1st gear without using throttle input & without having to apply some extra clutch pedal feathering at the car's current curb weight (verts are heavier than coupes) which does negatively affect low speed stop-go drivability, the lighter the flywheel is, the more torque from spinning flywheel mass inertia loss you will lose so to make up for this w\ a manual trans, you either have to resize the trans gearing ratios OR resize the rear end final gearing to gain more wheel torque (leverage) OR up the engine's actual low speed torque output (either thru retuning or just raising the engine's idle speed) to compensate IF you're looking to regain the lost idle "torque" from the reduction of spinning flywheel mass inertia due to the lighter weighted flywheel you've installed to move the same curb weighted chassis w\ the same engine output.

The 2 places where this is the most cost effective to change\adjust w\o changing the engine's low speed TQ output is either the flywheel's weight itself or the rear end final gearing ratio.

The best overall choice will indeed be the 4.10 gears as others have already stated....unless fuel mileage has a higher priority in your mind than the majority of us in here then the 3.73's will work out better than the OEM 3.55's if you're using a lightened CM steel flywheel since the amount of lost torque from spinning flywheel mass inertia reduction is less vs an all aluminum flywheel.

This is my 2 cents to add here. Hope this helps.

stkjock · May 9, 2020

Norm Peterson said:
I'm going to remind the drag strip crowd that we're not concerned with short times or ETs at all).

Heretic!!

oldyella · May 9, 2020

Hmm.. All excellent points! It took some SERIOUS re-learning to shift just from changing to the lighter flywheel and new clutch. (The flywheel is lightened CM steel btw) But I wanted to start shedding weight with every mod possible due to the extra weight the 'verts carry.

My driving is mixed local roads and freeways, but never more than 25 miles on the freeway one way. MPG is NOT a concern. I have a Lito tune, and I am already used to paying for premium 93 fuel.

GlassTop09 said:
so you're giving up some "torque" from loss of spinning flywheel mass inertia to move car off in 1st gear

True Story! I immediately felt the loss of torque off the line the minute the new flywheel was installed. I new something had changed, but wasn't sure how to gain that lost torque back. You just convinced me the bigger the better! 4.10 for the win!

Norm Peterson · May 10, 2020

stkjock said:
Heretic!!

I prefer the term 'nonconformist'

Always been that way, I guess, but it's at least made me think rather than blindly follow.

Norm

Waakeeen · May 11, 2020

Just curious what size rear tire y’all running with the 4.10s and crushing rpm around 80mph?

06 T-RED S/C GT · May 11, 2020

When I ran 4:10's with 285/40/18" tires, the RPM speeds at 80mph were approx between 2800-3000 while in 5th gear.

stkjock · May 11, 2020

https://www.s197forum.com/threads/tire-gearing-question.41254/#post-615829

86GT351 · May 11, 2020

4:10? nah.....I say go 4:30. These are performance cars. If you were looking for gas mileage you should have bought a Toyota Prius! LOL!

Norm Peterson · May 11, 2020

Sometimes you need to choose an axle gear to avoid having to make an upshift. Like just before the traps at the dragstrip to avoid fuel cut. Or to avoid needing to grab 3rd at autocross or a too-tall 5th or 6th out on a road course. Emotion-based suggestions like "don't fear the gear" can't help you in such situations.

Norm

raredesign · May 12, 2020

GlassTop09 said:
Ok OP, I think I understand what you are thinking here.....your right & are on the right track. 3.73 or 4.10 gears will help since you've switched to a lighter weight flywheel. Is your installed flywheel a lightened CM steel flywheel or is it an aluminum flywheel? If it is aluminum then you really need to swap to 4.10 gears but if it is a lightened CM steel flywheel then 3.73 or 4.10 gears will work. Most lightweight CM steel flywheels are around 15-16 lbs (aluminum is around 10-12 lbs) vs the OEM nodular iron flywheel at 22 lbs (actual weight as I've weighed mine myself & verified this) so you're giving up some "torque" from loss of spinning flywheel mass inertia to move car off in 1st gear without using throttle input & without having to apply some extra clutch pedal feathering at the car's current curb weight (verts are heavier than coupes) which does negatively affect low speed stop-go drivability, the lighter the flywheel is, the more torque from spinning flywheel mass inertia loss you will lose so to make up for this w\ a manual trans, you either have to resize the trans gearing ratios OR resize the rear end final gearing to gain more wheel torque (leverage) OR up the engine's actual low speed torque output (either thru retuning or just raising the engine's idle speed) to compensate IF you're looking to regain the lost idle "torque" from the reduction of spinning flywheel mass inertia due to the lighter weighted flywheel you've installed to move the same curb weighted chassis w\ the same engine output.

The 2 places where this is the most cost effective to change\adjust w\o changing the engine's low speed TQ output is either the flywheel's weight itself or the rear end final gearing ratio.

The best overall choice will indeed be the 4.10 gears as others have already stated....unless fuel mileage has a higher priority in your mind than the majority of us in here then the 3.73's will work out better than the OEM 3.55's if you're using a lightened CM steel flywheel since the amount of lost torque from spinning flywheel mass inertia reduction is less vs an all aluminum flywheel.

This is my 2 cents to add here. Hope this helps.

Now that is a well thought out and thorough reply. Excellent.

Sent from my iPhone using Tapatalk Pro

Pentalab · May 14, 2020

With oem 3.55 rear gears and a lighter flywheel... on paper, say if cruising at 50 mph.... punch it, the car should accelerate a little faster. You are not putting energy into spooling up a heavier flywheel.

Sure, I can see the issues if trying to take off from a stop /drag race. But once its going, acceleration should not be an issue. At the local .4 mile oval stock car track, the cars with the heavier flywheels all ran dead last.

One thing I did hear was it was either a lighter flywheel OR a lighter DS..but not both.

WNYGT5-0 · May 14, 2020

With a lighter flywheel there will be a bigger rpm drop between shifts and engine braking will be more pronounced But will rev quicker. There are pluses and minuses for every upgrade.

NEWB Here.. NOT your typical 4.10 scenario question

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