Looking At Flywheels For A 3'rd Gen
Senior Member
Joined: Aug 2002
Posts: 840
From: O.C. - CA.
I special ordered the XACT streetlight from clutchspecilaties for $225 and i'm pissed cause I still don't have it and that was last friday. RXecret7 has them in stock for the same price, damn! The prolight is about the same wieght as Mazdatrix's version. Alot of people are happy at that wieght but one of the guys I asked said the only problem he had was when he used the A/C then you could notice the bog. I love my A/C in the summer and can't live without it so I chose the streetlight. I ordered my counterwight from Mazdaformance which they ordered from Irvine, sent to Texas and then back to Irvine ...why won't Mazda let me pick it up? Anyhow it was $111 shipped. The 2nd best price and actually in stock was Mazdatrix for $119+tax&ship.
Member
Joined: Apr 2002
Posts: 73
I'm not sure all flywheels have their weights quoted in the same way. The Racing Beat aluminum flywheel is actually 8.2 lbs, but with the bolts and counterweight it is 12.5 lbs. That leads me to believe that the 9.5 lbs flywheel is quoted without the counterweight. Both are nice flywheels and I wouldn't expect anyone to notice a difference between the two when driving.
Also, the stock flywheel has most of it's mass around the outer edge of the flywheel, so it has a lot of inertia for its weight. The Racing Beat steel flywheel is 17 lbs (presumably with the counterweight, since that is how they weighed the aluminum one). However, even though it is only a few pounds lighter than stock, it is supposed to have 50% less rotational inertia. Rotational inertia is what matters. Mass is related, of course, but it is really the inertia that we care about.
I have been using a Racing Beat aluminum flywheel on the street and track (circuit) for 45K miles and it is great. I love the added responsiveness, and the downside of being less smooth when putzing around a parking lot doesn't matter to me. I don't have any problem leaving the line in normal (non-spirited) street driving, but it is different than with the stock flywheel. It is also much easier to rev-match for downshifts (easier to blip), and it matters less if you match perfectly. The reduction in rotational inertia feels fantastic -- it really wakes the car up. I'm not a drag racer, but I hear that a heavier flywheel is better for that.
-Max
Also, the stock flywheel has most of it's mass around the outer edge of the flywheel, so it has a lot of inertia for its weight. The Racing Beat steel flywheel is 17 lbs (presumably with the counterweight, since that is how they weighed the aluminum one). However, even though it is only a few pounds lighter than stock, it is supposed to have 50% less rotational inertia. Rotational inertia is what matters. Mass is related, of course, but it is really the inertia that we care about.
I have been using a Racing Beat aluminum flywheel on the street and track (circuit) for 45K miles and it is great. I love the added responsiveness, and the downside of being less smooth when putzing around a parking lot doesn't matter to me. I don't have any problem leaving the line in normal (non-spirited) street driving, but it is different than with the stock flywheel. It is also much easier to rev-match for downshifts (easier to blip), and it matters less if you match perfectly. The reduction in rotational inertia feels fantastic -- it really wakes the car up. I'm not a drag racer, but I hear that a heavier flywheel is better for that.
-Max
Senior Member
Joined: Oct 2002
Posts: 276
From: St. Louis
very informative post max! 
I think the reason a heavier flywheel is better for drag racing is because it technically "stores" more energy so its easier to get off the line. Now the question is, who sells a true 9.5lb flywheel that includes the weight of the counterweight and hardware?
Senior Member
Joined: Aug 2002
Posts: 840
From: O.C. - CA.
I think Racing Beat's is prolly the lightest. ACT's is 9 or 9.5lbs without the counterwieght. All he other ones are rated about that wieght as well. I have the streetlight because I don't want to sacrifice luxary or streetablility for a fraction of speed. But once I get used to it and if I want more, I can change it to a prolight by having the notches drilled out. The oval holes you see on the prolight are indented on the streetlight. I could swiss cheese it with a drill or pay a machine shop. Oh and it's 12 or 12.5lbs w/o flywheel, so it's lighter then RB's steel one.
Senior Member
Joined: Aug 2002
Posts: 840
From: O.C. - CA.
Well John wieghed my streetlight and said it was 14lbs+3lbs for the counterwieght=17lbs. Wow, that's only 5lbs lighter then stock. Since the ACT Prolight is at least 1lb heavier then the Racing Beat it might have been a better choice but I just couldn't do the extra $30 on my revuild budget. I'm hoping it will be enough of a difference that it was worth the money that I didn't have to spend.
Junior Member
Joined: Jul 2003
Posts: 19
Originally Posted by maxcooper' date='Mar 21 2004, 05:52 AM
I'm not sure all flywheels have their weights quoted in the same way. The Racing Beat aluminum flywheel is actually 8.2 lbs, but with the bolts and counterweight it is 12.5 lbs. That leads me to believe that the 9.5 lbs flywheel is quoted without the counterweight. Both are nice flywheels and I wouldn't expect anyone to notice a difference between the two when driving.
Also, the stock flywheel has most of it's mass around the outer edge of the flywheel, so it has a lot of inertia for its weight. The Racing Beat steel flywheel is 17 lbs (presumably with the counterweight, since that is how they weighed the aluminum one). However, even though it is only a few pounds lighter than stock, it is supposed to have 50% less rotational inertia. Rotational inertia is what matters. Mass is related, of course, but it is really the inertia that we care about.
I have been using a Racing Beat aluminum flywheel on the street and track (circuit) for 45K miles and it is great. I love the added responsiveness, and the downside of being less smooth when putzing around a parking lot doesn't matter to me. I don't have any problem leaving the line in normal (non-spirited) street driving, but it is different than with the stock flywheel. It is also much easier to rev-match for downshifts (easier to blip), and it matters less if you match perfectly. The reduction in rotational inertia feels fantastic -- it really wakes the car up. I'm not a drag racer, but I hear that a heavier flywheel is better for that.
-Max
Also, the stock flywheel has most of it's mass around the outer edge of the flywheel, so it has a lot of inertia for its weight. The Racing Beat steel flywheel is 17 lbs (presumably with the counterweight, since that is how they weighed the aluminum one). However, even though it is only a few pounds lighter than stock, it is supposed to have 50% less rotational inertia. Rotational inertia is what matters. Mass is related, of course, but it is really the inertia that we care about.
I have been using a Racing Beat aluminum flywheel on the street and track (circuit) for 45K miles and it is great. I love the added responsiveness, and the downside of being less smooth when putzing around a parking lot doesn't matter to me. I don't have any problem leaving the line in normal (non-spirited) street driving, but it is different than with the stock flywheel. It is also much easier to rev-match for downshifts (easier to blip), and it matters less if you match perfectly. The reduction in rotational inertia feels fantastic -- it really wakes the car up. I'm not a drag racer, but I hear that a heavier flywheel is better for that.
-Max
Senior Member
Joined: Mar 2004
Posts: 252
From: Calgary, Canada
Originally Posted by boostdfd3s' date='Mar 21 2004, 12:49 PM
very informative post max! I think the reason a heavier flywheel is better for drag racing is because it technically "stores" more energy so its easier to get off the line. Now the question is, who sells a true 9.5lb flywheel that includes the weight of the counterweight and hardware?
