what flywheel should i get?????
12-02-2003, 08:21 PM
#21
Originally posted by Mr. Potato Head
Well, maybe your article is wrong.
You don't buy a flywheel to stop easier at a stoplight and, really, you shouldn't downshift when coming to a stop. Just use the brakes. Of course that is a opinion.
You also don't downshift to slow down, you downshift to be in the right RPM range to power out of a corner as fast as possible. You use the brakes to slow down. Yes, sometimes it is more conducive to use other means to get around a corner. Sometimes you let the clutch out in the middle instead of before the corner if you want to pop the rear around, but that's another story.
Well, maybe your article is wrong.
You don't buy a flywheel to stop easier at a stoplight and, really, you shouldn't downshift when coming to a stop. Just use the brakes. Of course that is a opinion.
You also don't downshift to slow down, you downshift to be in the right RPM range to power out of a corner as fast as possible. You use the brakes to slow down. Yes, sometimes it is more conducive to use other means to get around a corner. Sometimes you let the clutch out in the middle instead of before the corner if you want to pop the rear around, but that's another story.
your telling me, you dont shift from 6th to 5th to 4th to 3rd when getting off a freeway to help you slow down?
remind me not to be your brake's...
sorry...
down shifting to get to a higher RPM in a lower gear will help you accelerate just as well as help you slow down...
GO out side, Drive up to 70 MPH in 3rd gear and let off the gass... you will slow down pretty fast...
THen drive up to 70 mph in 60th and see how much longer it takes you to slow down...
Last edited by Jason@Performance; 12-02-2003 at 08:24 PM.
12-02-2003, 08:41 PM
#22
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yeah, but all that shifting wears drivetrain components SO much faster. Personally, I'd rather do pads every 20k miles than have to do synhro's every 50k....much cheaper and much easier
Jason is right though..the lighter flywheel inherently has less rotational mass. The less mass you have, the easier the engine works, and thus, the easier it is for the engine's rotating assembly to spin..this works while accelerating and deccelerating.
If you have no tried a flywheel on the Z yet, even the NISMO at its seemingly "heavy" weight, then you are truly missing out. the NISMO is a substantial imporvement over stock in terms of how willing teh engien is to rev. As mentioned, the heavier the flywheel, the more inherent dampening it has, so noise and vibration are reduced as mass is added. Also the heavier the flywheel the easier it is to roll the car from a dead stop (this is a case where the increased inertia of the higher mass piece helps you). The lighter the flywheel the more difficult it is to move from a dead stop. NISMo is the best overall balance as its light enough to yeild a measurable difference, but heavier enough that its no harder to drive than stock, and provides stock like driving characteristics in just about all areas.
Personally, I see no reason for a flywheel any less than 14 lbs or so (where the stock one weighs 31 last time I measured it) for a street car. I would also strongly advise against any 2 piece aluminum unit for a street car. While great for strict track use, they become vey tiresome on the street, tend to warp much faster than their billet counterparts, and cannot be resurfaced (though they do have replaceable friction surfaces)
Jason is right though..the lighter flywheel inherently has less rotational mass. The less mass you have, the easier the engine works, and thus, the easier it is for the engine's rotating assembly to spin..this works while accelerating and deccelerating.
If you have no tried a flywheel on the Z yet, even the NISMO at its seemingly "heavy" weight, then you are truly missing out. the NISMO is a substantial imporvement over stock in terms of how willing teh engien is to rev. As mentioned, the heavier the flywheel, the more inherent dampening it has, so noise and vibration are reduced as mass is added. Also the heavier the flywheel the easier it is to roll the car from a dead stop (this is a case where the increased inertia of the higher mass piece helps you). The lighter the flywheel the more difficult it is to move from a dead stop. NISMo is the best overall balance as its light enough to yeild a measurable difference, but heavier enough that its no harder to drive than stock, and provides stock like driving characteristics in just about all areas.
Personally, I see no reason for a flywheel any less than 14 lbs or so (where the stock one weighs 31 last time I measured it) for a street car. I would also strongly advise against any 2 piece aluminum unit for a street car. While great for strict track use, they become vey tiresome on the street, tend to warp much faster than their billet counterparts, and cannot be resurfaced (though they do have replaceable friction surfaces)
Last edited by Z1 Performance; 12-02-2003 at 09:01 PM.
12-02-2003, 08:43 PM
#23
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Originally posted by Z1 Performance
yeah, but all that shifting wears drivetrain components SO much faster. Personally, I'd rather do pads every 20k miles than have to do synhro's every 50k....much cheaper and much easier
yeah, but all that shifting wears drivetrain components SO much faster. Personally, I'd rather do pads every 20k miles than have to do synhro's every 50k....much cheaper and much easier
12-02-2003, 08:43 PM
#24
Originally posted by Z1 Performance
yeah, but all that shifting wears drivetrain components SO much faster. Personally, I'd rather do pads every 20k miles than have to do synhro's every 50k....much cheaper and much easier
yeah, but all that shifting wears drivetrain components SO much faster. Personally, I'd rather do pads every 20k miles than have to do synhro's every 50k....much cheaper and much easier
the heavier the flywheel the slower the car will slow down in gear
the lighter the flywheel the faster the car will slow down in gear.
TILTON flywheel or JWT... even the NISMO... same effect... Just greater with the TILTON, then the JWT, then Nismo
12-02-2003, 08:58 PM
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Tell you what, I totally agree with your theory. But my experience dictates otherwise. I understand what you are saying Jason, as I downshift in my truck and drive it to hell and into the ground. I also have been racing cars since I was 16 and karts from 8-16. I get the principle of downshifting, braking, engine braking, etc. Still, in real life, for whatever reason, the engine braking is LESS with the JWT flywheel in my car. No matter what anyone says, I drive the car. I know and experience this every time I drive it. Bottom line.
12-02-2003, 09:04 PM
#27
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Potato - usaulyl I agre with your posts, but the laws of physics are against you on this one
Unless the JWT is actually heavier than the flywheel you took out, it is slowing down faster. The increased engine "braking" is one of the main attributes of the lightened flywheel, espcially for road racing guys, as it yields less time on the brakes.
Unless the JWT is actually heavier than the flywheel you took out, it is slowing down faster. The increased engine "braking" is one of the main attributes of the lightened flywheel, espcially for road racing guys, as it yields less time on the brakes.
12-02-2003, 09:09 PM
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Maybe the NISMO clutch is heavier than the stock clutch then. I swear to you I am not smoking anything. We have a Dallas meet coming up. I will let someone drive my car back to back with a stock Z and have them post as proof.
12-02-2003, 09:14 PM
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This is interesting. I think you both may be right actually. The lighter flywheel may cause the engine to slow more quickly when you take your foot off the accelerator.
Consider this as far as downshifting goes as a means to slow down. The heavier flywheel may resist speeding up to match the rear wheel speed after engaging the clutch following a downshift with no gas applied...........thereby slowing you down quickly. The lighter flywheel, having less mass, may be influenced by the speed of the rear wheels once the clutch is engaged following the downshift.........it may take longer to slow you down since less mass is resisting the inertia of the moving vehicle. This would explain why Mr. Potato Head felt he needed to hit the brakes harder in his experience with a lighter flywheel.
Jason: I will be calling you tomorrow to set up an appointment for that "gasket installation" we talked about yesterday.
Consider this as far as downshifting goes as a means to slow down. The heavier flywheel may resist speeding up to match the rear wheel speed after engaging the clutch following a downshift with no gas applied...........thereby slowing you down quickly. The lighter flywheel, having less mass, may be influenced by the speed of the rear wheels once the clutch is engaged following the downshift.........it may take longer to slow you down since less mass is resisting the inertia of the moving vehicle. This would explain why Mr. Potato Head felt he needed to hit the brakes harder in his experience with a lighter flywheel.
Jason: I will be calling you tomorrow to set up an appointment for that "gasket installation" we talked about yesterday.
12-02-2003, 09:17 PM
#30
Originally posted by Wedge
Jason: I will be calling you tomorrow to set up an appointment for that "gasket installation" we talked about yesterday.
Jason: I will be calling you tomorrow to set up an appointment for that "gasket installation" we talked about yesterday.
12-02-2003, 09:28 PM
#31
Originally posted by Mr. Potato Head
Tell you what, I totally agree with your theory. But my experience dictates otherwise. I understand what you are saying Jason, as I downshift in my truck and drive it to hell and into the ground. I also have been racing cars since I was 16 and karts from 8-16. I get the principle of downshifting, braking, engine braking, etc. Still, in real life, for whatever reason, the engine braking is LESS with the JWT flywheel in my car. No matter what anyone says, I drive the car. I know and experience this every time I drive it. Bottom line.
Tell you what, I totally agree with your theory. But my experience dictates otherwise. I understand what you are saying Jason, as I downshift in my truck and drive it to hell and into the ground. I also have been racing cars since I was 16 and karts from 8-16. I get the principle of downshifting, braking, engine braking, etc. Still, in real life, for whatever reason, the engine braking is LESS with the JWT flywheel in my car. No matter what anyone says, I drive the car. I know and experience this every time I drive it. Bottom line.
Perfect reading and also why carts do not do this...
The effects that this describes below are exadurated with a lighter flywheel because the lighter flywheel doesnt have as much mass to help keep the pistons inside the engine moving.
This was taken from - http://www.brendel.com/racing/glossary_1.shtml#E
Happy reading.
Engine braking
The effect of slowing down a vehicle by keeping the clutch engaged while in high gear without opening the throttle enough to maintain speed. The engine will want to drop to lower RPMs since not enough fuel is supplied to maintain the current RPM. But the vehicle is still going so fast that the engine would be forced to higher RPMs. Since the engine is difficult to turn over without supplying fuel, the energy of the moving vehicle will be transformed into the up-down motion of the moving piston inside of the engine. Essentially the opposite of what happens when fuel is supplied to the engine. A clutch-kart typically cannot take advantage of engine braking, since the clutch just disengages below a certain RPM. Also, engine braking is not an effective way of slowing down a vehicle and is therefore not often used in racing. The brake is many times more expensive.
12-02-2003, 09:37 PM
#32
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Oh Jason Jason Jason. I could have told you that if you had just asked! I was not comparing karting to driving the Z by the way. Anyways, you go ahead and read tonight. Let me know when you get your flywheel put in, go 80 in sixth gear and let off the gas. Let me know how amazing the engine braking is.
12-02-2003, 10:07 PM
#33
Originally posted by Mr. Potato Head
Oh Jason Jason Jason. I could have told you that if you had just asked! I was not comparing karting to driving the Z by the way. Anyways, you go ahead and read tonight. Let me know when you get your flywheel put in, go 80 in sixth gear and let off the gas. Let me know how amazing the engine braking is.
Oh Jason Jason Jason. I could have told you that if you had just asked! I was not comparing karting to driving the Z by the way. Anyways, you go ahead and read tonight. Let me know when you get your flywheel put in, go 80 in sixth gear and let off the gas. Let me know how amazing the engine braking is.
You dont want to rely on engine braking, BUT you said that by lifting your foot off the gas while in gear you notice the car takes longer to slow down is the complete oposite of what physics and proven facts of how engines work show.
Put engine braking aside, what does all of this mean... it means that when crusing you always need to apply the gas to stay at a constant speed because if you apply less gas for a moment the car will slow down faster (not extremely fast like smack your head on the steering wheel) but will slow down more so with a lighter flywheel then with a heavier flywheel.
Do you know what "Heal-Toe" is? The whole reasoning behind Heal-Toe shifting is to smoothly brake and while brakind down shift and Rev Match by hitting the accelerator to match the RPM the lower gear will be at the current speed. This way you work with not only the brakes slowing you down but also with some assistance from the engine braking. The engine braking is relized more with a lighter flywheel due to the Inertia facts listed above in many other posts. If engine braking did not occur from lighter flywheels etc there would be no reason at all to heal-toe shift.
Maybe you never lifted your foot off the gas while at the top of 3rd gear before and let it die down. But, when you are at your meet, go to the top of 2nd, take your foot off the gas, leave it in gear see what happens.. then go in someone elses car and do the same thing..
heck you will even see a difference going 20mph in 1st gear and doing the above.
If you have any fishing line weights, tie a couple to a string.. spin the string over your head then stop spinning it. the ***** will eventually loose height and slow down. Inertia keeps them moving. THen do the same with less weight on the string (remove some *****) the less weight, the less inertia, the faster they will slow down.
12-03-2003, 05:07 AM
#34
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Ok this has become worthless. Please stop regurgitating what you have read on the web or wherever and LISTEN!!!! Damn it man. I RACE CARS! You do not need to copy and paste definitions. I simply do not care what you are reading and what physics say about a flywheel. There is something simple called real world experience that is directly conflicting what you are reading about the engine braking with a lighter flywheel. YOU are the one with your eyes closed just copying and pasting something else anytime someone replies to you. STOP! Geez man you are not progressing this topic ANY further and have now started to regress it. Why don't you go back and read Wedge's post as I think he has a great idea on why this is happening. If you cannot understand the concept ask me and I will explain it to you. Please don't get something else to copy and paste that I am not sure you understand. Let's stay relevant.
12-03-2003, 05:26 AM
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I have a JUN flywheel, and my experience is different than yours. I would have to say I agree with Jason. My car also slows down quicker when I let off the throttle and have the car in gear.
12-03-2003, 05:28 AM
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That's fine then. Mine doesn't. I am only relating MY experience. Jason is finding that hard to understand. Tell me something though. Does it do it in sixth as well as 2nd? Because I am talking about 5th and 6th gears and not lower gears like 2nd. Next time I have the car out I will check out 2nd.
12-03-2003, 06:00 AM
#38
Originally posted by Mr. Potato Head
That's fine then. Mine doesn't. I am only relating MY experience. Jason is finding that hard to understand. Tell me something though. Does it do it in sixth as well as 2nd? Because I am talking about 5th and 6th gears and not lower gears like 2nd. Next time I have the car out I will check out 2nd.
That's fine then. Mine doesn't. I am only relating MY experience. Jason is finding that hard to understand. Tell me something though. Does it do it in sixth as well as 2nd? Because I am talking about 5th and 6th gears and not lower gears like 2nd. Next time I have the car out I will check out 2nd.
Enjoy your ride
12-03-2003, 06:05 AM
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I'll tell you what mine feels like. It feels like an automatic when you let off the gas at high speed and just lighlty tap the brake and you feel that sort of surge and you have to press the brake harder to start slowing down. It isn't harder to slow the whole time, just when you start pushing the brakes it surges a little like an auto. And believe me, I do enjoy the ride!
12-03-2003, 07:46 AM
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One more repetitious opinion
Generally speaking, engine braking is not wise. It puts stress on your engine and gearbox. If you need to stop, step on the brakes. That is what they are there for. Replacing brake pads is a lot cheaper than rebuilding engines and gearboxes.
As for the flywheel, just recognize that this mod will affect driveability. But I like mine and am glad I got it.
As for the flywheel, just recognize that this mod will affect driveability. But I like mine and am glad I got it.