OEM Piston Weight - Re-Balance? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

HotLavaJoe · 08-07-2020, 08:16 PM

Hi all,

I'm planning on rebuilding my 2013 FRS engine soon with all OEM parts except for pistons. I want to go with 13.5:1 compression and 87mm diameter to get a tiny bit more NA power with E85.

My question is: When I get aftermarket pistons that are a different weight from OEM (I cant find OEM piston weight info anywhere) will I have to re-balance the engine in any way?

Thanks,

Joe

Grady · 08-08-2020, 10:59 AM

No.

Steveiam · 08-09-2020, 02:46 PM

Why not swap out for stronger rods while everything's apart?

Jdmjunkie · 08-09-2020, 09:13 PM

Quote:

Originally Posted by Steveiam

Why not swap out for stronger rods while everything's apart?

Not to mention lighter for maximum revs and NA goodness!

Turdinator · 08-10-2020, 02:00 AM

Lighter rods don't seem to be a thing for the FA20

PulsarBeeerz · 08-10-2020, 12:26 PM

Quote:

Originally Posted by Steveiam

Why not swap out for stronger rods while everything's apart?

Quote:

Originally Posted by Jdmjunkie

Not to mention lighter for maximum revs and NA goodness!

No need for stronger rods when NA and apart from one fella with custom Ti con rods the OEMs are plenty light.

If anything maybe make sure the current or new OEM rods are all of equal weight and balanced since the new pistons will be.

86TOYO2k17 · 08-10-2020, 12:34 PM

Get some head work done while the heads are off. oversized valves, springs, port/polish etc... maybe even a cam. Rev her out to 7800 with the 13.5 compression, and get an ace 150 header for that top end. Maybe toss in some ITBs. you could Probably have The highest WHP non stroked NA FA20.

PulsarBeeerz · 08-10-2020, 12:45 PM

Just throw $15k at it. NBD

Jdmjunkie · 08-10-2020, 01:53 PM

Quote:

Originally Posted by PulsarBeeerz

Just throw $15k at it. NBD

It is only money.

NoHaveMSG · 08-10-2020, 01:59 PM

Quote:

Originally Posted by Jdmjunkie

Not to mention lighter for maximum revs and NA goodness!

That way the rocker arms come out at higher velocity

86TOYO2k17 · 08-10-2020, 02:12 PM

Quote:

Originally Posted by PulsarBeeerz

Just throw $15k at it. NBD

Why stop at $15k? Mortgage interest rates are at historic lows.

RayRay88 · 08-11-2020, 02:21 AM

Quote:

Originally Posted by 86TOYO2k17

Get some head work done while the heads are off. oversized valves, springs, port/polish etc... maybe even a cam. Rev her out to 7800 with the 13.5 compression, and get an ace 150 header for that top end. Maybe toss in some ITBs. you could Probably have The highest WHP non stroked NA FA20.

Probably not worth it unless you can address oiling issues. All that money just to watch a bearing spin before your first oil change.

PulsarBeeerz · 08-11-2020, 02:07 PM

Quote:

Originally Posted by RayRay88

Probably not worth it unless you can address oiling issues. All that money just to watch a bearing spin before your first oil change.

Yup the only ones that seem to have it figured out are Element Tuning and after you add up all the stuff mentioned, you are well over $15k... Smarter to wait for the KMiata K24 swap in reality.

Turdinator · 08-11-2020, 11:28 PM

Quote:

Originally Posted by HotLavaJoe

Hi all,

I'm planning on rebuilding my 2013 FRS engine soon with all OEM parts except for pistons. I want to go with 13.5:1 compression and 87mm diameter to get a tiny bit more NA power with E85.

My question is: When I get aftermarket pistons that are a different weight from OEM (I cant find OEM piston weight info anywhere) will I have to re-balance the engine in any way?

Thanks,

Joe

If you are rebuilding it to gain performance, why not spend a little extra and get it fully balanced regardless?

08-07-2020, 08:16 PM	#1
HotLavaJoe Junior Member Join Date: Aug 2020 Drives: 2013 FRS 6MT Hot Lava Location: Philadelphia Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	OEM Piston Weight - Re-Balance? Hi all, I'm planning on rebuilding my 2013 FRS engine soon with all OEM parts except for pistons. I want to go with 13.5:1 compression and 87mm diameter to get a tiny bit more NA power with E85. My question is: When I get aftermarket pistons that are a different weight from OEM (I cant find OEM piston weight info anywhere) will I have to re-balance the engine in any way? Thanks, Joe

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08-09-2020, 02:46 PM	#3
Steveiam Member Join Date: Jun 2019 Drives: 86 Location: Dallas, TX Posts: 65 Thanks: 12 Thanked 20 Times in 12 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	Why not swap out for stronger rods while everything's apart?

08-10-2020, 12:34 PM	#7
86TOYO2k17 Senior Member Join Date: Jan 2018 Drives: 2017 toyota 86 Location: PNW Posts: 2,131 Thanks: 336 Thanked 1,188 Times in 781 Posts Mentioned: 16 Post(s) Tagged: 0 Thread(s)	Get some head work done while the heads are off. oversized valves, springs, port/polish etc... maybe even a cam. Rev her out to 7800 with the 13.5 compression, and get an ace 150 header for that top end. Maybe toss in some ITBs. you could Probably have The highest WHP non stroked NA FA20.

08-10-2020, 12:45 PM	#8
PulsarBeeerz Senior Member Join Date: Mar 2017 Drives: JRSC BRZ SOLD Location: Ohio Posts: 934 Thanks: 676 Thanked 739 Times in 396 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Just throw $15k at it. NBD

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