LS7 clutch kit for my LS3 480 Aluminum Flywheel or no ??

[DT69Cam]

This subject seems to be up for debate one way or the other. LS7 clutch kit. Aluminum flywheel or no ??? Mostly a street driven car.

[andrewb70]

The stock LS7 flywheel is very heavy, but having said that, I run this clutch in both my GTO and my Cougar. Adding an aluminum flywheel will get you back to the weight of a stock LS1/LS6 clutch, which is definitely not "too light." For a mostly street car, the heavier clutch assembly makes driving easier. I voted for stock flywheel.

Andrew

[DT69Cam]

Thank you Andrew. That is what I was thinking, use the stock flywheel.

[130fe]

I have the stock one in my LS3, no issues at all on the street or autocross.

[icemanrd19]

I have the stock one in my LS3, no issues at all on the street or autocross.

same here as well

[analyte]

I'm pulling on, stock LS7 flywheel and clutch here as well. Very happy with it!!

[DT69Cam]

Thanks Guys.

[Craig@Bowler]

I see this same question come quite a bit on my phone conversations with guys deciding what the best set up will be for their car and it looks like you've been given a lot of great advice already so I will just leave this bit of wisdom that I've come across from the Ram Clutches website. Hopefully this will be beneficial to anyone else who may be considering going one way or the other.



The flywheel is primarily an inertia device. As the flywheel spins it stores energy or inertia that helps move the mass of the vehicle as you engage the clutch.

Factory flywheels are designed to apply the optimum amount of stored energy to provide good drivability for the vehicle. Vehicles with smaller engines have relatively heavy flywheels due to the extra inertia needed for a smooth transition to engagement. Reducing the weight of the flywheel, while increasing performance, could reduce the drivability of the vehicle.

Under racing conditions, the flywheel weight can be used to control the inertia applied to the drivetrain. For instance, if a vehicle tends to ‘bog’ upon engagement of the clutch, increasing the flywheel weight will increase the inertia needed to launch the vehicle smoothly. Too much flywheel weight may cause excessive inertia to be applied, causing the tires to spin. Reducing flywheel weight under this condition will reduce the inertia applied to the vehicle and allow smoother acceleration.

Aluminum flywheels are used in drag racing high horsepower applications which require the clutch to slip as the vehicle leaves the line. Steel flywheels are used primarily in street driven vehicles.

Other load factors can effect flywheel selection, such as rear gearing or transmission gearing. With the abundance of gearing choices available today, it is possible to use almost any flywheel if the proper selection of gears is made. This was not always the case – in the 70’s when the gearing choices were not available, racers had no choice but to use the flywheel weight to control the vehicles on launch. It is more efficient to use a light flywheel and proper gearing than to use tall gearing and a heavier flywheel.

How do I select a Proper Flywheel?

When we are asked for a flywheel recommendation, several factors are considered to make a proper recommendation.

What is the primary use of the vehicle? For street driven vehicles, a steel flywheel will provide easier engagement and longer clutch life.

What is rear end gearing? Lower (higher numerically) gears will make engaging the clutch easier, while higher gearing requires the clutch to be slipped more on takeoff for a smooth transition.

What is the weight of the vehicle? If it is over 2800 pounds, we will generally recommend steel. Remember that the flywheel's job is- to help you get the car accelerating smoothly. If you have ever driven a vehicle and tried to pull off in second gear, you know you had to slip the clutch significantly more to get moving than if you started in low. This is the same effect you would notice if the flywheel is too light.

Another factor to consider, especially for those of you in this forum, is track raced cars. If you are building a car that will see a significant amount of track time an aluminum flywheel can be beneficial to help the engine accelerate/decelerate on the turns. Ultimately my best advice is to get the clutch that fits with the majority of the driving you will be doing.

[analyte]

Craig,
Great information right there!!

[DT69Cam]

Thank you Craig !!

[Centerforce]

We would agree; a stock or lightened steel flywheel is usually the best solution for most applications short of purpose-build racecars.

[DT69Cam]

We would agree; a stock or lightened steel flywheel is usually the best solution for most applications short of purpose-build racecars.

Thank you.

[JodysTransmissions]

DT you have received some great flywheel info from these guys. Here is my take from the other side of the coin!

I love using aluminum flywheels and have been building these type of drivelines for 20+ years. My personal '70 Chevelle street car has a 15lb flywheel with a stock ZZ502/502. It is all about the 1st gear torque multiplication if you are good candidate to make it work on the street.

Basic lightened flywheel facts; for every 1lb removed off the flywheel has the effect of removing 100lbs off the car by the way it reacts. If you did an A/B comparison of a stock 30lb flywheel vs a 15lb aluminum flywheel; your car would react like it is 1500lbs lighter when romping on and off the gas pedal. This is why aluminum flywheel cars need a higher 1st gear torque multiplication to make it streetable and enjoyable.

Here is a great analogy;
An "Aluminum Flywheel" is like riding a two-stroke racing dirt bike, they can make you car jumpy and jerky
A "Heavy Flywheel" is like riding a full dresser Harley Davidson, they are smooth and steady

Is an aluminum flywheel for everyone, no, but when a driveline is properly engineered to use one they are very streetable and fun.

[DT69Cam]

Thank you Jody. At this point I think a stock flywheel will suit me just fine. Thanks everyone.

[amargari]

I went through this a few months ago but I was using a clutch combo from a 2005 CTS-V which has a very heavy dual mass flywheel. Below are weight combos for various setups. As you can see the LS7/Ram Aluminum combo at 51 lbs was the lightest. I went with Mantic ER2 Street Clutch Kit in my 73 Camaro which is lighter than the stock LS7 but heavier than stock LS1 or LS7/Ram combo. The Mantic combo woke the car up compared to the factory CTS-V combo.

CTS-V LS6 Clutch/Flywheel 76 lbs
LS7/LUK (Stock) Clutch/Flywheel 59.5 lbs
LS7/Ram Aluminum Flywheel 51 lbs
Stock LS1 53 lbs
Mantic 57 lbs

[andrewb70]

Consider this as another datum point. I had a 3000 pound RX7 with a LS6 engine, T56, and 3.55 gears. I ran a flywheel and clutch assembly that was right at 20 pounds. Not just the flywheel, but all of it...I had no issue driving it on the street and it revved so fast that it threw belts until I went with the Katech non spring loaded belt tensioner.

Also keep in mind that a lighter flywheel/clutch combination will make shifting much easier. I don't know how much this effects synchronized transmissions (probably some) but it makes a huge difference with a dog-ring transmission. I had a dog-ring T56 in my RX7 and with the lightweight clutch the shifting was much easier than how my Cougar shifts (also dog-ring transmission and LS7 package).

I was ever so close on pulling the trigger on a lightweight RPS carbon/carbon clutch, but in the end the $2500 price tag (vs. $400 for the LS7) was just too much.

Bottom line, if you just want a nice driving car and aren't looking to squeeze every bit of performance out of your combo, the stock LS7 package is hard to beat. You can go with the genuine GM parts, or get the Luk equivalent, which is exactly the same stuff, just cheaper.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Andrew

[chuckd71]

The whole ls7 clutch kit with a stock flywheel, slave, etc is only $240 or less. At that price you can try it and not be out much if you don't like it.

[TANKMASTERJ]

So if you guys bought aan LS7 tat already has a Fidanza 12# flywheel but had thee heavy LS9 dually dissc clutch setup that was almost like new, would you run this setup or do to a. McCleod RST?

[andrewb70]

So if you guys bought aan LS7 tat already has a Fidanza 12# flywheel but had thee heavy LS9 dually dissc clutch setup that was almost like new, would you run this setup or do to a. McCleod RST?

If I already owned what you have, I would just use it.

Andrew

[TANKMASTERJ]

Thanks Andrew