Compression ratio 12.5:1. Bye-bye Super charger & Turbo build? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

fred_boosted · 11-02-2011, 02:13 PM

Hey, guys.

See Here: http://www.ft86club.com/forums/showthread.php?t=2131

Now we know the Compression ratio is 12.5:1

This is a nightmare for people who want do a turbo or a super charger build.

According to my knowledge, there are some ways that we could reduce the CR. I want discuss with you guys.

First, get a thinner gasket. This only can reduce a little CR, for example 0.2 or 0.3. Even we drop it to 12:1 its still not good.

Second, get after market pistons, rods. I think this is the best way to reduce CR, we may could reduce it from 12.5:1 to 11:1 or 10:1. But if we want crazy high boost...

Last, engine build. A whole new block? If you got tons of $$$ then go for it.

Those are just my thoughts based on my own knowledge, I didn't do a lot of search, so correct me if I'm wrong.

BTW, intercooler, BOV, waste gate, piping, turbo will those destroy the balance of the car? I don't know, looking for answer.

KaliKev · 11-02-2011, 02:20 PM

Also, what about freeing up horsepower in N/A form?

If an intake, and exhaust can get us 220hp i'll be happy with that, but would much prefer 250+hp with FI

Dave-ROR · 11-02-2011, 02:26 PM

Thinner head gaskets will RAISE compression, not lower it.

WingsofWar · 11-02-2011, 02:36 PM

^ yeah you want a thicker gasket, but realistically it doesnt warrant a very good CR gains or losses.

On that note.. Boxer engines are a bit funky with gaskets

EJ251-Ej255 gaskets are thinner than EJ257 STI headgaskets.. BUT EJ257 gaskets give a HIGHER compression ratio to the same blocks....weird right?

Dave-ROR · 11-02-2011, 02:39 PM

Quote:

Originally Posted by WingsofWar

^ yeah you want a thicker gasket, but realistically it doesnt warrant a very good CR gains or losses.

On that note.. Boxer engines are a bit funky with gaskets

EJ251-Ej255 gaskets are thinner than EJ257 STI headgaskets.. BUT EJ257 gaskets give a HIGHER compression ratio to the same blocks....weird right?

I don't know EJ stuff at all, but what else is different? Or does just changing gaskets increase it?

There's something else involved there because and thinner but otherwise identical gaskets will always increase compression...

Nurburgring · 11-02-2011, 02:39 PM

Do some research on boosted S2000's. It has been done a thousand times on totally stock engines, with 11.7:1 compression ratio. Results are impressive (420whp @ 12 psi for your typical bolt-on turbo kit using 93 octane, easily 500 with E85). A thicker headgasket is a bad band-aid, if you want to go high boost better build the engine and use lower CR pistons.

The biggest enemies on boosting this car will be:
- DI head (complexity, tuning)
- Space / packaging
- Lead time to having a decent standalone system available

fred_boosted · 11-02-2011, 02:47 PM

Quote:

Originally Posted by Nurburgring

Do some research on boosted S2000's. It has been done a thousand times on totally stock engines, with 11.7:1 compression ratio. Results are impressive (420whp @ 12 psi for your typical bolt-on turbo kit using 93 octane, easily 500 with E85). A thicker headgasket is a bad band-aid, if you want to go high boost better build the engine and use lower CR pistons.

The biggest enemies on boosting this car will be:
- DI head
- Space / packaging
- Lead time to having a decent standalone system available

Nice tip!

What about mill the block? Is this safe and not that costly?

A set of after market pistion+rod. But those are just over my budget limit.

I'm considering an used BMW M3 E90/92 now... which is... shame..

ryridesmotox · 11-02-2011, 02:48 PM

DI doesn't have any negative effect on boosting anything... At this point the 12.5:1 compression is pretty much the worst thing they could have done. It's going to necessitate one of 2 things... Either Meth/H2O injection or Ethanol or both. But even then I'm guessing that you are only going to be able to run like 8PSI... but you will get good power.

The only good thing about that is... the engine will have a fully forged lower end... It really almost has to... 12.5:1 at 8k rpm or however fast they want to spin this thing... it has to have a forged lower end

Allch Chcar · 11-02-2011, 02:56 PM

Quote:

Originally Posted by fred_boosted

Hey, guys.

See Here: http://www.ft86club.com/forums/showthread.php?t=2131

Now we know the Compression ratio is 12.5:1

This is a nightmare for people who want do a turbo or a super charger build.

According to my knowledge, there are some ways that we could reduce the CR. I want discuss with you guys.

First, get a thinner gasket. This only can reduce a little CR, for example 0.2 or 0.3. Even we drop it to 12:1 its still not good.

Second, get after market pistons, rods. I think this is the best way to reduce CR, we may could reduce it from 12.5:1 to 11:1 or 10:1. But if we want crazy high boost...

Last, engine build. A whole new block? If you got tons of $$$ then go for it.

Those are just my thoughts based on my own knowledge, I didn't do a lot of search, so correct me if I'm wrong.

BTW, intercooler, BOV, waste gate, piping, turbo will those destroy the balance of the car? I don't know, looking for answer.

Kindly, you are not knowledgeable enough to speak on this subject at all.

WingsofWar · 11-02-2011, 02:58 PM

STI runs forged cranks and rods factory, if anything id expect this car to have a forged crank since its expected to perform in the upper registries of the RPM range.

KaliKev · 11-02-2011, 02:59 PM

Quote:

Originally Posted by Allch Chcar

Kindly, you are not knowledgeable enough to speak on this subject at all.

You don't have to be a **** about it.

fred_boosted · 11-02-2011, 03:12 PM

Quote:

Originally Posted by Allch Chcar

Kindly, you are not knowledgeable enough to speak on this subject at all.

Yes I'm not, just want begin to talk this topic.

And listen to adivces.

Why can't you just say why I'm wrong and tell us how to do thing right?

RRnold · 11-02-2011, 03:13 PM

Just a thought Fred...maybe this might not be the car for you! How about drive it first before deciding if it needs more power. My .02

Dave-ROR · 11-02-2011, 03:18 PM

Quote:

Originally Posted by fred_boosted

Nice tip!

What about mill the block? Is this safe and not that costly?

A set of after market pistion+rod. But those are just over my budget limit.

I'm considering an used BMW M3 E90/92 now... which is... shame..

Milling the head and or the block will also increase compression. You want more room in there instead of less

11-02-2011, 02:13 PM	#1
fred_boosted Senior Member Join Date: Oct 2011 Drives: 2008 EVO X GSR (Sold) Location: USA Posts: 100 Thanks: 8 Thanked 4 Times in 4 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Compression ratio 12.5:1. Bye-bye Super charger & Turbo build? Hey, guys. See Here: http://www.ft86club.com/forums/showthread.php?t=2131 Now we know the Compression ratio is 12.5:1 This is a nightmare for people who want do a turbo or a super charger build. According to my knowledge, there are some ways that we could reduce the CR. I want discuss with you guys. First, get a thinner gasket. This only can reduce a little CR, for example 0.2 or 0.3. Even we drop it to 12:1 its still not good. Second, get after market pistons, rods. I think this is the best way to reduce CR, we may could reduce it from 12.5:1 to 11:1 or 10:1. But if we want crazy high boost... Last, engine build. A whole new block? If you got tons of $$$ then go for it. Those are just my thoughts based on my own knowledge, I didn't do a lot of search, so correct me if I'm wrong. BTW, intercooler, BOV, waste gate, piping, turbo will those destroy the balance of the car? I don't know, looking for answer. __________________ I could get Maserati Quattroporte or BMW M3/M6. But I gived up. Why? Because thats just not my style.

11-02-2011, 02:26 PM	#3
Dave-ROR Site Moderator Join Date: Dec 2010 Drives: Stuff Location: Florida Posts: 10,317 Thanks: 955 Thanked 5,965 Times in 2,689 Posts Mentioned: 262 Post(s) Tagged: 8 Thread(s)	Thinner head gaskets will RAISE compression, not lower it. __________________ -Dave Track cars: 2013 Scion FRS, 1998 Acura Integra Type-R, 1993 Honda Civic Hatchback DD: 2005 Acura TSX Tow: 2022 F-450 Toys: 2001 Chevrolet Corvette Z06, 1993 Toyota MR2 Turbo, 1994 Toyota MR2 Turbo, 1991 Mitsubishi Galant VR-4 Parts: 2015 Subaru BRZ Limited, 2005 Acura TSX Projects: 2013 Subaru BRZ Limited track car build FS: 2004 GMC Sierra 2500 LT CCSB 8.1/Allison with 99k miles

11-02-2011, 02:36 PM	#4
WingsofWar MODERATOR-SAMA Join Date: Oct 2009 Drives: Swagtron Scooter Location: Seattle Posts: 2,685 Thanks: 345 Thanked 1,561 Times in 524 Posts Mentioned: 81 Post(s) Tagged: 0 Thread(s)	^ yeah you want a thicker gasket, but realistically it doesnt warrant a very good CR gains or losses. On that note.. Boxer engines are a bit funky with gaskets EJ251-Ej255 gaskets are thinner than EJ257 STI headgaskets.. BUT EJ257 gaskets give a HIGHER compression ratio to the same blocks....weird right? __________________

11-02-2011, 02:39 PM	#6
Nurburgring Member Join Date: Sep 2011 Drives: S2000, AE86, RSV10000R, 911, EP91 Location: Chile Posts: 47 Thanks: 0 Thanked 11 Times in 3 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Do some research on boosted S2000's. It has been done a thousand times on totally stock engines, with 11.7:1 compression ratio. Results are impressive (420whp @ 12 psi for your typical bolt-on turbo kit using 93 octane, easily 500 with E85). A thicker headgasket is a bad band-aid, if you want to go high boost better build the engine and use lower CR pistons. The biggest enemies on boosting this car will be: - DI head (complexity, tuning) - Space / packaging - Lead time to having a decent standalone system available Last edited by Nurburgring; 11-02-2011 at 03:03 PM.

11-02-2011, 02:48 PM	#8
ryridesmotox Senior Member Join Date: Oct 2011 Drives: 2010 Chevy Cobalt SS, 59 Ford F100 Location: Carlsbad, Comi-fornia Posts: 127 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	DI doesn't have any negative effect on boosting anything... At this point the 12.5:1 compression is pretty much the worst thing they could have done. It's going to necessitate one of 2 things... Either Meth/H2O injection or Ethanol or both. But even then I'm guessing that you are only going to be able to run like 8PSI... but you will get good power. The only good thing about that is... the engine will have a fully forged lower end... It really almost has to... 12.5:1 at 8k rpm or however fast they want to spin this thing... it has to have a forged lower end __________________ 2010 Chevy Cobalt SS Treadstone Performance Stage 3 kit: CAI, Charge Pipes, TR8 intercooler, Maf Relocate, 52MM Turbosmart BOV, 3 inch catless downpipe, 3 inch catback, borla XR1 muffler, Exedy Hypersingle, TWM short throw shifter, 24PSI HPtuned by Terminator2 on E85/91

11-02-2011, 02:20 PM	#2
KaliKev FT86 News Addict Join Date: Sep 2011 Drives: Toyota FJ Location: United States Posts: 386 Thanks: 3 Thanked 42 Times in 26 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Also, what about freeing up horsepower in N/A form? If an intake, and exhaust can get us 220hp i'll be happy with that, but would much prefer 250+hp with FI

11-02-2011, 02:58 PM	#10
WingsofWar MODERATOR-SAMA Join Date: Oct 2009 Drives: Swagtron Scooter Location: Seattle Posts: 2,685 Thanks: 345 Thanked 1,561 Times in 524 Posts Mentioned: 81 Post(s) Tagged: 0 Thread(s)	STI runs forged cranks and rods factory, if anything id expect this car to have a forged crank since its expected to perform in the upper registries of the RPM range. __________________

11-02-2011, 03:13 PM	#13
RRnold 2 wheel member Join Date: Feb 2010 Drives: JZA80, 997.1, Taco Location: SoCal->NorCal Posts: 4,330 Thanks: 1,318 Thanked 938 Times in 480 Posts Mentioned: 9 Post(s) Tagged: 0 Thread(s)	Just a thought Fred...maybe this might not be the car for you! How about drive it first before deciding if it needs more power. My .02 __________________

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