Aftermarket Crank Pulley Install

[Koa]

Originally Posted by Octane

Toyota Tech here. I was planning to get this for my car so I started to ask around the more experienced guys at the shop, and one of the heavy line guy said he already got a few blown engine with the light weight crank pully. He works around alot of FR-S's and was also one of the techs that was invited to work at the Toyota grand prix celebrity race as a tech. Now I'm not scaring anyone away from using it, but I just want to lay the facts on the table. Also theres not much that directly links the pully to the blown engine, he just said he noticed a few of the blown ones had it and for some was the only mod as far as he can tell.

I'm nitpicking (I know it's a common phrase), but facts are commonly held truisms (some 'facts' can still be, in actuality, untrue). The trusim at current is that LWCP will not be the cause of a blown motor, all else being equal. Not to say this isn't valuable information and perspectives that will one day become fact! Thanks for the heads up and info for real

Personally staying away from LWCP after disappointing results given the effort on other platforms

[jay1989]

Wow what a PITA I just busted 2 ratchets trying to get that damn thing off crappy craftsman tools. Guess its time to go find my impact drill

[stugray]

Originally Posted by alpax

Would be interesting to have the actual math behind that.

Frankly speaking the whole idea of replacing the crank pulley is like that "fart in a hurricane", but everyone confirms, that the difference is noticeable. The SC parasitic load is also just "noticeable" - it's not that huge. That's why I'm simply guessing they could be the values of a similar magnitude. And because "+" of a pulley and "-" of a SC happen at the same RPM range, it's just logical to try and sum them up.

Actually during my morning drive today I did notice several times that the engine RPM climbed slightly easier. Could be a placebo effect of course.

I wouldn't expect the crank pulley to make a huge difference, but even if it would give a slight improvement for its money - why not?

I have thought a lot more about the concept of lightening rotating drivetrain components and the effect on vehicle acceleration.
I have come to the conclusion that the effect that a LWFW or a LWCP (or a light weight driveshaft) will have on vehicle acceleration should be exactly the same as just removing the same weight from the vehicle as a whole.

There will definitely be a benefit to the engine in general by having lighter components (lower internal forces) and will rev faster under no load.

However there should not be ANY noticeable difference on a dyno since the car's total momentum is not part of the equation.
You should feel faster acceleration with the lighter components, but it should not be any different than just removing the same mass of components from the carpets or the interior for example.

[CoupedUpSubie]

Originally Posted by jay1989

Wow what a PITA I just busted 2 ratchets trying to get that damn thing off crappy craftsman tools. Guess its time to go find my impact drill

Ratchets are not for breaking bolts free. A breaker bar is what is needed. It has a pretty solid pivot point. I used a cheaper torque wrench set at its highest setting as my breaker bar wasn't long enough, not the proper tool though just as a ratchet isn't. Go buy a new ratchet and a 36" breaker bar, you will thank yourself even if it is craftsman.

[jay1989]

Originally Posted by CoupedUpSubie

Ratchets are not for breaking bolts free. A breaker bar is what is needed. It has a pretty solid pivot point. I used a cheaper torque wrench set at its highest setting as my breaker bar wasn't long enough, not the proper tool though just as a ratchet isn't. Go buy a new ratchet and a 36" breaker bar, you will thank yourself even if it is craftsman.

just picked them up from the parts store before reading this and did the trick. I should have known better than to try and break it loose with a ratchet but it is all I had at the moment and they have never let me down before.

Oh well what can you do, everything is going back together now thank god. It is dark and cold but that is ok Should be up and running again in another hour or so.

[phobos512]

Thanks for this thread, gave me all I needed to know for my install just now.

[kiichiro]

I never got why people change out this pulley with one with less balance and of a softer metal and same diameter with no vibe dampening

why

[Malt]

Originally Posted by kiichiro

I never got why people change out this pulley with one with less balance and of a softer metal and same diameter with no vibe dampening

why

Who says the available LWCP's are less balanced than the stock one and what does a "softer" metal have anything to do with its ability to function as a pulley?

[phobos512]

Originally Posted by kiichiro

I never got why people change out this pulley with one with less balance and of a softer metal and same diameter with no vibe dampening

why

Well, for me it,was the ability to get 4 lbs off the front of the engine. Not for engine performance per se but overall light weighting. I'm not going anywhere as extreme as some folks but I'm doing what I can and a few pounds off the forward extreme of the car helps, if only a little, to reduce MOI.

[stugray]

Originally Posted by phobos512

Well, for me it,was the ability to get 4 lbs off the front of the engine. Not for engine performance per se but overall light weighting. I'm not going anywhere as extreme as some folks but I'm doing what I can and a few pounds off the forward extreme of the car helps, if only a little, to reduce MOI.

The truth is: Unless you are building a motor from the ground up with performance in mind, the pulley will do ZERO for performance.
Shedding the weight from the pulley will have the exact same effect as shedding the weight from anywhere else on the car.
But 4 lbs IS 4lbs.

Or you could take a dump before you go out on the track - your choice.

[phobos512]

Originally Posted by stugray

The truth is: Unless you are building a motor from the ground up with performance in mind, the pulley will do ZERO for performance.
Shedding the weight from the pulley will have the exact same effect as shedding the weight from anywhere else on the car.
But 4 lbs IS 4lbs.

Or you could take a dump before you go out on the track - your choice.

Well, that's true with respect to gravity but if you understand moments of inertia, and your post implies that you don't, you understand that removing weight from the extreme ends of a car will increase its ability to change direction. Which is what I was talking about.

[stugray]

Originally Posted by phobos512

Well, that's true with respect to gravity but if you understand moments of inertia, and your post implies that you don't,

I DO understand moments of inertia better than most on this forum.
There are a number of reasons that the pulley will make almost zero difference:
1 - the pulley is as close to the spin axis of the rotating mass as possible.
Since the moment of inertia is proportional to the square of the distance from the rotational axis, and the pulley is as close as you can get, it makes the smallest contribution to rotational inertia of any component in the drivetrain. I have stated it before, the BELT makes a greater contribution to rotational inertia than the pulley does.

2- When the car is accelerating, the engine is fighting the mass of the vehicle, NOT just the rotational mass of the drivetrain.
At this point, the limiting factor is the vehicle mass and the rotational mass is a tiny fraction of the total mass of the system.

This is why the pulley makes a difference when revving the engine by itself, but is in the noise on a dyno pull.

I do also understand polar momentum. so removing weight from either end of the car is important.
Taking the spare out of the trunk will make about a 10X difference compared to losing 4lbs from the pulley.

[eddieflyinv]

Originally Posted by stugray

I have thought a lot more about the concept of lightening rotating drivetrain components and the effect on vehicle acceleration.
I have come to the conclusion that the effect that a LWFW or a LWCP (or a light weight driveshaft) will have on vehicle acceleration should be exactly the same as just removing the same weight from the vehicle as a whole.

There will definitely be a benefit to the engine in general by having lighter components (lower internal forces) and will rev faster under no load.

However there should not be ANY noticeable difference on a dyno since the car's total momentum is not part of the equation.
You should feel faster acceleration with the lighter components, but it should not be any different than just removing the same mass of components from the carpets or the interior for example.

I will say I don't notice much difference as far as speed or anything, it seems to have a little bit faster acceleration but who knows maybe that's just the placebo effect,
What I do notice most, and what makes it feel entirely worth doing, is the improved engine response when heel toe shifting. it just feels, for a lack of better words, better lol.
That's me though, everyone is different and for some that change of feel may not seem like it's worth anything
I also got my 3pc set for a really good deal, so as far as I'm concerned pulleys were a solid buying decision

[menikmati]

Used this to install the GrimmSpeed crank pulley, thanks OP.

I had to yank the hell out of my breaker bar in order to break the bolt loose. Torquing to 94 ft/lb afterwards felt like cake compared to breaking the bolt loose.