Well, I've had this RB steel flywheel laying around for a little while. I thought about selling it, but in the end decided to keep it. So, I whent out and bought a FD auto counter weight from Rob@Pineapple (Yes, the FD and a n/a 89+ counterweights are the same thing.) So yesterday I dropped the tranny, and bolted it up. Install was realy easy, as long as you've dropped the tranny a couple of times. Total time that I spent on this project was 3hrs, from the time I parked the car in the garage until the time I pulled it out.

From Idle to 3krpms, the motor did'nt seem to rev to much faster. This could be due to me having no working 6 port sleeves. No worry though, as I'm use to it. From 3k and up, it revs a whole lot faster. Night and day difference. On the road in 1st and 2nd the car is noticably faster. In 3rd it is'nt as noticable, but there is a gain. I did'nt get a chance to try 4th, but I'm not expecting to much up there anyways. If I where to have to guess, It would feel like the car (free'd up actually) picked up 15ish hp in 1st and 2nd, and maybe around 10hp in 3rd.

Driveability is no different, other than the idle. I'm gonna turn it up a hair to 900. After you give the motor a good rev, it'll come down and almost stall. No big deal, as I've dealt with light weight flywheels before. When the motor misses a bit, its now more noticable too.

If I had to do it all over again, I would have opted for the aluminum flywheel. But I picked it up for cheap, and so I used it.

This is what order I would have modded my car, if i could have done it all over again.

Exaust
Intake
port the intake manifolds
flywheel
HI-6
port the motor
S-afc, and then dyno tune it.
If the motor would have let go, I would have thrown a port job in there too, whenever it happened.

sorry for my rambling, CJ

 

You have just convinced me to get an aluminum flywheel.

 

I hear you on the Aluminum Flywheel. RPM's drop so rapidly for me aswell resulting In occasional stall. No big deal, I bumped up the Idle. Besides that, great mod with no drivability Issues I keep hearing about.

 

well if the revs drop looks like your gonna have to use some "heel & toe" action

 

After I get back from doing the Disney Land thing next week, the secret "Pineapple Juice" is going to be installed. Pineapple Juice is kinda like Don't Be a Rikki's secret sauce...but for non-turbo Rx-7s. Maybe after the first 1/4 mile runs, I'll take it back to the dyno for some tuning and hopefully break the 200rwhp mark. I'm hoping to trap around 102mph this year, as I pulled a 15.1@95 last year. Wish me some luck guys. CJ

 

Pineapple juice???

 

Is it really true that a lighter flywheel will hurt launches to the point of negating its gains in first through third revving along the 1/4 mile course? Something tells me you will still burn your tires if you ease out the clutch at 6000 rpm while mashing the gas, light flywheel or not. I fry my tires doing this at 3000. Opinions?

 

SO you would reccomend the aluminum fw then?

 

I am confused on how a flywheel can change horsepower. How is that possible?

James

 

It doesn't cahnge the HP, it just lets you get the the HP that you have faster. Its cause the enigne doesn't have to accelerate as much rotating mass.

 

Newtons Second Law
A property of mass is its resistance to a change of velocity. This is quantified by Newtons second law which says that the acceleration is:

Proportional to the net external force.
Inversely proportional to its mass.
In the direction of the force.
In other words:

F=ma

where:

F = net force
m = mass
a = acceleration
There is also an equivalent for rotation

T = I

where:

T = torque
I = inertia
= angular acceleration
When working in 2 or 3 dimensions, then F, a, T and can be represented as vectors and m and I as matrices.

 

Its completely true about a aluminum flywheel being nearly impossiable to launch with the same results as a heavy flywheel. I had one on my 12a peripheral, along with a bunch of other lightning parts. Once you break the tires loose, its extremely difficult to get wheel spin under control. Either that, you'll bog the motor. If you don't beleive me, contact Rob, or any other well known drag racer.

I would recommend a alum. flywheel. As long a your not a %100 drag racer.

Pineapple Juice is a secret for now.

CJ

 

TWO TANKS OF NAWWWS.

 

I agree with the statement that it's pretty hard to pull the same launches using an alum. flywheel. But since I'm not a 100% drag racer (more like a 30/70 mix), I'll be picking up an alum. flywheel soon . I think I've seen pineapple juice at my walmart, it just recently started coming in on the trucks, took some petitioning but it finally got here...now where do I put it?

 

Next time I do an oil change, Im going to replace with 100% Pineapple juice. I think it will lubricate better, and free up an additional 15-20HP. Plus I can have a refreshing drink while Im under the car.....