Lightened flywheel

[Hoghead]

I am building a 302 set up with a single plane manifold, and ported 2.02/1.60 valve 351 heads, simply because I have the parts already. Cam is healthy and more top end oriented

3.31 rear end, 2.94 1st gear T5(Z) on 15" wheels, so a relatively low first gear
5th gear is .80 for a close ratio box

A new billet steel flywheel is on the shopping list and I am pondering flywheel weight. The current choice is 25 lbs VS 17.3 lbs so quite a difference.
I am not sure if the light flywheel be too light for street use with my gearing, and engine set up?

I see the advantage of a light flywheel on a road track. Anyone running a lightened flywheel on the street?

 

[0neoffive]

Opinions Don't Matter

Way, way back (last century)in my SCCA days, we all toyed with various flywheels. There was a very slight improvement exiting corners, but not enough to take our emphasis away from handling as the real priority.

 

[Hoghead]

Way, way back (last century)in my SCCA days, we all toyed with various flywheels. There was a very slight improvement exiting corners, but not enough to take our emphasis away from handling as the real priority.

I was wondering if a fairly light car like the Tiger, with a relatively low 1st gear, and cammed engine, would be a bit too difficult to drive on the street when starting off from a light.

 

[MT Roads]

What if.....

The relatively low gearing, like the light weight, will help with street / stop light driving. The single plane manifold & high rpm cam, not so much.
No direct experience with a setup like that, but from what I have heard from others, it should not be overly touchy to handle on the street.
This may be one of those mostly emotional decisions. You get some extra bragging rights, and likely a bit more of a lumpity idle. Actual performance would probably need to be measured, so more of a question of what you want & what you are willing to put up with.

But my suggestion would be, "Do It". Otherwise, you will never know what it would be like & will always ask yourself the question [What if...?].

 

[Forrest39]

I have an aluminum flywheel with an Edelbrock performer top end kit and Holley Sniper fuel injection. It sits on a 302 bored .030 over making it 306. It rev's quickly and might be marginally more prone to stalling than with a heavier flywheel, but certainly not overly so. If you were shooting for a higher output motor, I wouldn't hesitate on going with a lighter flywheel.
-Kevin

 

[Maliburevue]

I run a Fidanza aluminum flywheel (16.5 lbs) on a 331 stroker in my Tiger. Cam is an Edelbrock 2221, .520" lift I and E. Good street cam, but not overly radical. I absolutely love the way the engine revs up and down so quickly. I also run a wide ratio tranny with a 2.90 first gear, so take-offs are effortless. I can slowly let out the clutch without even touching the gas.

IMO if you were running a 4000lb Mopar with wrinkle wall slicks, you would need the rotational intertia of a steel flywheel, but in a 2500 Tiger with limited tire width, I break traction long before the engine would ever bog.

All the Tiger engines I have built use an aluminum flywheel. Here are several.

Gary

 

[Hoghead]

I run a Fidanza aluminum flywheel (11lbs) on a 331 stroker in my Tiger. Cam is an Edelbrock 2221, .520" lift I and E. Good street cam, but not overly radical. I absolutely love the way the engine revs up and down so quickly. I also run a wide ratio tranny with a 2.90 first gear, so take-offs are effortless. I can slowly let out the clutch without even touching the gas.

IMO if you were running a 4000lb Mopar with wrinkle wall slicks, you would need the rotational intertia of a steel flywheel, but in a 2500 Tiger with limited tire width, I break traction long before the engine would ever bog.

All the Tiger engines I have built use an aluminum flywheel. Here are several.

Gary

That is a LOT lighter than I had in mind.
Our first gears are almost identical - What rear end ratio do you have?

 

[Maliburevue]

Gearing

Typo, my aluminum flywheel is actually 16.5 lbs. Sorry about that.

I run my original toploader 4 speed converted to wide ratio with a 2.90 first gear and factory 2.88 rearend gears. When I get a chance, I will drop in 2.72 rearend gears for a 6% 'overdrive' in fourth. Won't make much of a difference in first, since the 2.90 is so low, but I'll drop ~200 rpms in fourth on the highway, i.e. 'poor man's overdrive'.

Gary

 

[theo_s]

I see the advantage of a light flywheel on a road track. Anyone running a lightened flywheel on the street?

I have a Mustang T5 (3.35 first) with 3.31:1 rear end gears, and I run a Ram aluminum flywheel... for at least half the autocross starts I've done, I'd still start in second to avoid having to shift pretty much as soon as the car left the start box. No issues with it on the street at all. I have a project to build a Z spec transmission so I'll go to the 2.95 first but I do not expect any issue there either.

 

[Hoghead]

I have a Mustang T5 (3.35 first) with 3.31:1 rear end gears, and I run a Ram aluminum flywheel... for at least half the autocross starts I've done, I'd still start in second to avoid having to shift pretty much as soon as the car left the start box. No issues with it on the street at all. I have a project to build a Z spec transmission so I'll go to the 2.95 first but I do not expect any issue there either.

I bought the 17.3 lb steel flywheel
Gearbox is a T5Z with the 2.95 first, and a .8 fifth

So with the higher first ratio, you are now starting in 2nd - will it not be even lower with the 2.95 first?
I have 3.07's now and will try it with this rear end ratio before deciding to change to the 3.31's

 

[theo_s]

So with the higher first ratio, you are now starting in 2nd - will it not be even lower with the 2.95 first?

Yes, but it will be at least 10% more useful than the 3.35 first that's currently in there. In the long, long term, what would help is a 3.07 rear end (or go back to the factory 2.88). But that becomes a whole other project that I don't have time for... maybe someday.