29 replies to this topic

[Dirtcircle86]

Heeltoeauto sells em for $335 but 2KRacing has them for $285. Neither have an actual weight listed unless I totally overlooked it. I didn't get time to call either one today.

I have only found one local machine shop, Macon Motor Sports, that will even think about lightening an iron flywheel. They are all worried about it coming apart. Understandable.

Guy gave me an over-the-phone guesstimate of $120 to mill the flywheel and another hour ($60) to shave the crank pulley.

So my debate is, $285 for an aluminum flywheel that weighs ???? or $120 for one that weighs maybe 11 or 12#'s?

I think, with the diff welded, some suspension adjustments, installation of my engine goodies, and some experience driving it, the car is a top 2-3 runner. I want to have fun, and first place is way more fun than second!

I want to install a light flywheel next week when I pull the tranny for the weld. I think it will be a significant source of acceleration.

Thanks for any input!

[cbstdscott]

I have a lightened flywheel and it has not hand grenade-ed after 10+ years.

[Dirtcircle86]

The guy (at Macon) asked me if I had heard of any coming apart and I told him I had not.

Scott, or anyone else, do you have any photos of your cut flywheel? Macon and I would like an idea of where the weight is typically removed. He talked like he would cut from both the front and back. It looks like there is quite a bit to be removed from the ring gear itself, which is out where it really counts.

I'm still leaning toward the AASCO, but I need to figure out what they weigh.

Anyone have any testimonials (or time slips) comparing stock -vs- lightened -vs- aluminum?

[squareback]

I contacted Marcus at HeelToe a while back to ask what that flywheel weighs, and I believe he said it's under 9 pounds. FWIW, I have run into resistance from local machine shops about machining a stock flywheel also, so I had decided to get one of the AASCO units. For my cost to machine a stock flywheel, it's not much more to get the AASCO unit which was built to be lightweight. But like Scott said, people have machined the stock unit and had no issues.

[jsgprod]

I have two lightened steel ones and a couple of aluminum ones. Not sure what the actual weight of the aluminum one in the car is right now, but the whole flywheel, disc & PP weight is about 13lbs. That's the heavy one, .

Of the two steel ones, one is just under 10lbs and it was done around 1990, I used it for years in the race car but at the moment it's in my street CRX. Ridiculously sensitive throttle with that in there too. The other steel one came with another race car I bought a few years ago, it's about 11 lbs. Not sure when it was done but I think it was in the early/mid 90's also.

 

Have you ever driven one of these with a welded diff? Be prepared for a completely different driving experience! Not saying it's bad but the first time you try to turn the wheel you'll be in for some significantly different feedback.

 

Jay

[cbstdscott]

Have you ever driven one of these with a welded diff? Be prepared for a completely different driving experience! Not saying it's bad but the first time you try to turn the wheel you'll be in for some significantly different feedback.

 

Many +'s on that comment. I have a very aggressive LSD in my CRX and tight turns are... different.

 

Once you drive a car with a lightened flywheel you will soon discover why the factory sends them out with heavy flywheels.That weight in the reciprocating system is to take some of the thinking out of a transition from a standing start to forward motion at low rpms. I have 40+ years of manual transmission driving under my belt and the ONLY time I stall from a standing start is when I forget that my CRX needs a few more rpms and a bit more attention to the clutch release than a standard street car. And while a lightened flywheel in a 1.5 litre engine will not make the LS V8 community shiver in fear, it does make a marked improvement in acceleration and a worthwhile mod to make on a car that will be driven aggressively.

 

Scott

[Dirtcircle86]

I'm new to racing a front wheel drive so I'm not used to any of it yet.  The car isn't really "set up" yet and will take a few runs to see what it likes.  I am even farther behind than the car.  I think adjusting to a locked front will be easier than trying to make it turn with the open diff.  EVERYTHING I have read about welding a FWD for clay oval says to do it.  There is resistance/reasoning from the guys who have never done it but the way it is described and the way I have seen it on the track, it's the only way to compete. 

 

At our track, there are two packs of cars.  A pack with welded diff's fighing for the front, and a pack of open diff's tyring to not get lapped.  The open diff is just too unpredictable with ever changing track conditions.  Welded cars cruise around the turns with barely a lift on turn in; those of us running open fishtail and lose incredible amounts of momentum on exit.  Spinouts are very common.  Before welding was legal, I wanted to be the fasted open car there.  I did that on the first night so there is no point to stay open. 

 

As for the light flywheel being an issue with start up, our paddock is gravel and the track is very nice clay.  It's very similiar to asphalt by feature time.  My goal is for it to go from 5,000 to 7,000 RPM's VERY quickly. 

 

EDIT:  2KRacing lists the AASCO at 7 lbs.  My bad

 

EDIT#2:  They "sold the last one yesterday" and will take two weeks to build another.  I'm headed to the machine shop.

[Maine_Honda_Racer]

Lightened the one in my asphalt stock car. No problems.

[WOLFCRX]

I have lighted ones in both my crx Si's, no issues on them. They are 18 lbs stock, I now have one at 9 and the other at 9.5, been running them for years.

[Dirtcircle86]

I can't for the life of me find a photo of a lightened A1 flywheel. As in, where the 8 or 9 pounds was removed. The machinist is being pretty conservative and speculated he could safely remove 4 or 5 pounds. If he removes the areas we talked about, he may be pretty accurate. There is just over a 1/2" (thickness) removable from the outer half of the back of the flywheel, and more on the inside of the pressure plate on the front. If that makes sense.

What bothers me is the the pilot is too small for his balancer so he can't balance it without my crankshaft..... I have a spare, but its in my other build that hasn't been opened yet. He doesn't think it will matter since there are no balance marks on the flywheel. His theory is, "if its true now, it will remain so during machining." I really don't want it to come apart.

Should I take him a crankshaft? Or trust his educated guess (30 years of automotive machining)?

[rallyxcrx]

My lightened flywheel has been fine, no problems. I don't like to admit I have a welded diff as many people are against this. It does however work well in the dirt. For pavement I run a ST bar in the front, a 17" steering wheel with bicycle handle bar tape, and padded driving gloves, and I just can't steer at real slow autocrosses, Dave  

[Dirtcircle86]

Rallyxcrx, did you just have it cut or did it need material removed for balance? I'm trying to locate another shop that can check the balance withou having to pull the crank from my other motor. I do have an EW crank I can take him, if they have the same snout. I'm not sure how that works but he says he can balance it using a crank but it won't fit his balancer as-is.

If 2kracing had one in stock it would be in the mail already...... Heeltoeauto lists them for an additional $50

Welded appears to be the only way to go on dirt. I'm running it open again tomorrow but hope its the last time. If I can get the flywheel cut or get an aluminum one here by late next week, I will have the tranny out and welded before it gets here.

[rallyxcrx]

I just had another one done for a spare motor, a crank grinder lightened and balanced it for 150.00, he didn't need a crank to do it. It's about 1\2" thick, Dave

[Dirtcircle86]

I'll try again Monday to find somebody that can balance it. There's a driveshaft shop close that may be able to do it. The guy I dropped it off to does general engine machining but specializes in big block dragsters. Claims the pilot on his balancer is too big to fit in the Acura flywheel.... I dunno. Says if he has a crank, he checks it for balance then mounts the flywheel and spins it again. He cant cut it til wednesday or thursday so I have a day or two to find someone with the correct balancer, otherwise I have to pull the crank from my other motor. I have an EW crank but its pretty beat up and probably bent from a rod flopping around in there.

Ill get it to work. I weighed all my different tire/wheel sets today and found the 15" Fat 5's and 14" Factory Acura "sawblades" (or whatever they are) weigh in at 28#. The 13" steelies are 24#.... The tires on 'em are 3/4 of an inch narrower though. Ill try 'em out but with the lightened flywheel, they may not be enough to hook. Pretty dry too. May need some tranny fluid. Sorry, ill shut up

[ballade]

I also ran a lightened factory flywheel for years with no issue. 

think it was under 10lbs.