What spools a turbo faster: Light flywheel or Heavy flywheel
 

Me and a couple friends have been having this argument for a couple weeks and I thought I'd see what you guys say. I would have asked this on H-T but I want to be proven RIGHT.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Heavy, more load. your welcome ;)

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Wouldn't the lighter make it boost faster but come time to shift it's gonna fall out of boost if you don't shift fast enough unlike the heavier flywheel will keep the momentum of the engine going and not drop down thus still keeping it in boost? I dunno I'm just some dumb injen :1

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Lighter will rev up more quickly. Revs = exhaust gas. Exhaust gas = spool. You could theoretically spool a turbo on lower amounts of exhaust gas, though over a longer time. So with a heavy flywheel you will may get it to spool at a lower RPM.

Don't matter though, a heavy flywheel is absorbing more energy in the system than a lighter flywheel (dutring acceleration), so the lighter will always result in higher WHP during engine acceleration.

As for the issue with boost falling during shifts, if you upshift so slowly that the rev's drop far enough that when you dump the clutch they pick up again you have some major problems with your driving style.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

that's for damn sure. I'm one of the quickest shifters in my group of people, people say my car sounds like i shift quick like an F1 car :6

but I would think a lighter flywheel will result in higher power and better acceleration, regardless of boost. it's kind of like asking which is better, a cold air intake or an header back exhaust :1 both will make it better

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Yeah I gotchya but we're not making a buying decision, just a hypothecial debate on the flywheel weight and which will make boost first.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

How are you figuring which is first I would think the heavier flywheel would create more boost at lower rpms but the lighter one may hit boost quicker over the same period of time at a higher rpm...I don't know I'm not a fan of light fly wheels for some reason

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Sorry when I say "first" I mean at a lower RPM :-[

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Lighter.That is my guess but maybe wait till JD hits this thread he will probably be able to completly discuss all the physics behind etc.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Lighter will just rev faster. I thought I heard that heavy flywheels are better for turbo though cause they allow you to stay in boost longer ?

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

The real question is what makes your car faster...

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

tru, light flywheel= less inertia=fall on face upon launch. :(

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Only if you launch to low and then it's a little easier to bog.


JP

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

heavy, more inertia for the shifts, more load on the engine. engine does more work, exaust gas is haWTur. plus the ngine stays spinning with mad jdm force inbetween shifts.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

chalk up another for the heavy flywheel.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

the engine will do the same work regardless, but with a light flywheel more of the work is done at the road surface.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

^tru dat

^im going to have to agree, @WOT, you have the same amout of pre-charged air going in/out of the engine to spool the turbo w/ a light flywheel or a heavy one. I understand that load is what spools a turbo, but what is load? If I pack a bunch of sand bags in my car, thats load too, will it spool faster? I dont think so. Also, back to whiteys statement "which would make it faster" Im going to hypothosize (sp owns me) that the CFM of air moved through the engine before its pressureized is going to spool the slug, not the wight of the flywheel, thats only going to make it reach higher revs quicker, which IMO would create more CFM of air to spool it (more RPMs means more CFM of air is moving thru the engine and into the turbo, thus spooling it SLIGHTLY quicker) It wouldnt make a BIG difference, probably not enough to notice (the spooling) but youd notice that the revs & speed climb faster, because like mentioned above "more work is put to the road".

This is my guess, I dont know what the hell im talking about, but to me that kinda makes sence. :1

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

question was which spools sooner
answer is heavy

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

more load= quicker spool

Heavy will make you spool sooner, but im with these guys, i think lightweight is faster.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

this is a pointless question...which do you want? to be able to say you spool faster or go faster? i switched from a stock to lightweight and the lightweight is faster. if heavier were better manufacturers would make heavier aftermarket flywheels.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

It's not a question of "what to buy" or "what will make my whip more unique" It was just a discussion between me and some friends and I wanted to see what some HMT guys had to say about it.

Thanks for the replies ;)

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

I mean in the end its all about theories. We still don't know what will work from experience. What i suggest doing is buy a lightened flywheel and find out. Simple as that and you'll go down in history to be the nigga that found this ---- out :6. But if i were to guess i would say the heavier flywheel spools it first and the lightened flywheel makes more whp :y

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

I have an 8lb in my crx, and I make boost on the launch limiter. wtf are you guys talkin about you cant spool a turbo without load? If you dont want to lose boost btwn shifts, dont let off the gas completely.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

I disagree with you one this in certain cases heavier is better, don't drift cars use heavier flywheels? companies make narrow band A/f guages dose that mean they are good...my real problem with light flywheels and crank pulleys is this...The crank is balanced from the factory and I assume the flywheel and crank pulley are too so changing one or both in my opinion would off set it, this can be proven with some of the guys killing oil pumps with the pulleys...I guess I don't have any hard proff but I would only assume this is true with the flywheel and may decrease engine life, I say if you do it get it rebalanced

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Usually brand new flywheels are balanced. Flywheel do not dampen crank wobble therefore it doesnt matter if it is aftermarket or not. Crank pulleys have the more important role when it comes to engine life.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

I wont ---- with aftermarket pulleys. I know too many ppl who have had their engine die of oil starvation bc of them.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

i dont think its because of oil starvation, its the lack of the harmonic balancer that throws the crank off balance and in turn will spin the rod/main bearings

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

Yup.Break oil pump gears as well.I have a CTR pulley sitting here for my motor im building but Im scared of using it as it has no damper,harmonic rubber piece.I think the way to go might be to get a OE pulley milled down to remove the power steering and AC pulleys.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

You can't spool a turbo without load. A load doesnt have to be towing a house, your engine always has *some* load.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

well no ---- your going to build boost, hello 2-step? ::)

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

i believe in lightened flywheels, but i also believe you have to have a good clutch to grab too.. as for whether it spools faster or not i dont know but i do know it made my all motor b16 crx alot faster.. ie. keeping rpm's high and not dropping in between shifting.... ---- aftermarket pulleys.....

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

i have a 7lb flywheel in my car and it will spool quicker than a heavier one, but it also sucks for turbo cars becasue once you get on the clutch the rpm's drop very quickly and then you're out of boost. Happens to me. I want to put in my old stock flywheel because I need more rotating mass to keep the rpm's up while shifting.
It's also nearly impossible to chirp the tires.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

this thread is funny. now people are saying that a heavier flywheel will spool faster lmao. thats like saying you can carry a 100 pound box up a flight of stair faster than you can carry a 10 pound box up the stairs. part of it is physics and part of this is common sense. some of you are choosing flywheels that are wayyy to light i.e. 6-7 pounds of course they will drop during shifting a better lightweight flywheel choice would be 11-12-13 pound flywheels i have a 12 pound jun and its perfect you get used to it you just have to launch at higher rpms and if in between shifts theres not much of a drop unless you shift slow as hell, i've found that for better times its best to rev match to keep the flywheel spinning. the only downsides are loss of torque down low and in the middle of the powerband and less inertia so the flywheel will spin faster but will also decel faster than a oe flywheel so!:

light weight flywheel pros :revs faster, builds boost faster,instant engine response,higher fwhp #'s due to free'd up weight,clutch "bite" will be more notice able,allows higher launch rpm
light weight flywheel cons: less inertia, loss of tq,flywheel slows down faster between shifts(the lighter the wheel the faster it slows down),

oe flwheel pros: flywheel remains spinning off throttle during shifting, more torque,more inertia,very slow flywheel decel between shifts

oe flywheels cons: more weight in rotating assembly,slower revs,slightly slow to spool max boost

you decide

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

no drift cars use light flywheels, because it lets them get the rev's up and get into boost sooner. I do know this because alot of my friends drift too (short list of the cooler cars: S13 RHD RB25DET (now sold)S13 SR20DET x2, S14 SR20DET, S14 RB25DET x3, S14 KA24DET now swapped to 1JZ-GTE). Lighter flywheel = better.

Honda engines are completely balanced internally. Prople having problems with bearings being taken out by underdrive pullies should blame the fact that the cheap ebay pullies are probably not balanced. If the flywheels were balanced with the engine, then you would need to index it to install it on the crank the same way when you remove it.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

my input is that the heavy flywheel will make boost at lower rpms but itl take just as long to get there as the light flywheel wich would boost at higher rpms.i beleive this will only happen only in first tho the rest of the gears should b the same . i also think the ligher fly wheel will make ur car faster so w/e

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

I'm waiting for Steve to come in here and own the this thread like all of the others that he post in.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

i know there are too many inputs here rite now, we need someone that actually knows what there talking about from experience

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

this might clear it up for some of you...
http://autonet.ca/SunDrive/Toronto/s...46410-sun.html

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

My verdict is this thread is pointless. Does more money mean you own more drugs, or does more drugs mean more money in your pocket. :P

I always use a stock flywheel because I feel the weight helps keep the momentum of the tiny honda motors we play with. You don't have alot of displacement waiting for the rest of the weight to get up to speed, you have low displacement and the weight helps keep the momentum going. (that's once you get it spinning) And even with 10k posts, my opinion isn't valued by any engineers. It's just an opinion.

Re: What spools a turbo faster: Light flywheel or Heavy flywheel
 

im speaking from experience. i've driven cars with many different weight flywheels 7lb-stock and i know the differences and characteristics im not speaking from "hear say" in the end it all comes down to preference. the way i compare is to -----:
some like it shaved(lwf) and some like it hairy(oemfw) either way its still -----