follow ft86club on our blog, twitter or facebook.
FT86CLUB
Ft86Club
Delicious Tuning
Register Garage Members List Calendar Search Today's Posts Mark Forums Read

Go Back   Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB > Technical Topics > Forced Induction

Forced Induction Turbo, Supercharger, Methanol, Nitrous


User Tag List

Reply
 
Thread Tools Search this Thread
Old 12-17-2012, 04:18 AM   #57
sw20kosh
Senior Member
 
Join Date: Jul 2012
Drives: 2013 Black FR-S
Location: SF
Posts: 3,030
Thanks: 881
Thanked 2,014 Times in 990 Posts
Mentioned: 153 Post(s)
Tagged: 1 Thread(s)
HP is calculated from Torque and rpm.

An engine that has a high hp number will have a high redline. Why? Because torque generated at high RPM = high HP # relative to torque #.

An engine that has a high torque number relative to HP will have a low redline (like 4,000-5,000).

Study a few dyno graphs that have both torque and HP on them.

Simply saying "I want torque" means nothing. You have to specify where you want it.

On a car that revs to 7500 rpm you will generally always have a higher HP # unless you are choking the engine in the upper rpm range. Look at the s2000's engine. It has low torque, but this torque is carried out all the way to redline. This creates a huge HP number of 240HP. F1 cars rev at least twice as high and generate even more HP compared to their torque.

If what you desire is more torque in the lower rpm range, then a positive displacement supercharger is your best bet. If sized properly you wont be suffocating the engine or generating too much heat in the upper rpm range and you will have lots of torque down low.
sw20kosh is offline   Reply With Quote
Old 12-20-2012, 03:34 PM   #58
3MI Racing
Pro Subie Engine Nerd
 
3MI Racing's Avatar
 
Join Date: Feb 2012
Drives: empty spot for an FR-S/BRZ
Location: Virginia
Posts: 96
Thanks: 8
Thanked 36 Times in 19 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by carbonBLUE View Post
so.... at 12.5:1 compression you would need to run 9.9, so pretty much twice the psi to make the same power BUT heres the other factor, when you lower compression you INCREASE the amount of volume you can compress in the cylinder, = more air = more fuel can be used = more power
Your math is a decent guesstimate for how it will preform, without going into effect that the lower compression ratio has on quench, volumetric efficiency, tumble and flame propagation. Even more important on the GDI, your dish in the piston plays a LARGE effect on the spray (and thus vaporization of fuel) from the DI which cools your pre-ignition in-cylinder temps.

Also, more air and more fuel (at the added few CC's) doesn't not mean more power. There is a lot more to an engine than that when you are talking volume changes that are this small. With the added volume, that can also mean more residual gas too, so you how have a lower % of your volume being fresh air and fuel.

With that being said, you also said that you would have lower temps with a lower compression ratio. With all things being equal, I would agree. However, as stated, not all things are equal. You may have a nice 'chunk' of your now being hot exhaust (residual gas).


...just telling the rest of the story
3MI Racing is offline   Reply With Quote
Old 12-20-2012, 04:03 PM   #59
carbonBLUE
Reverse Burnouts
 
Join Date: Oct 2011
Drives: 2013 Argento FRS
Location: dallas!!!
Posts: 2,894
Thanks: 707
Thanked 1,257 Times in 592 Posts
Mentioned: 30 Post(s)
Tagged: 1 Thread(s)
Quote:
Originally Posted by 3MI Racing View Post
Your math is a decent guesstimate for how it will preform, without going into effect that the lower compression ratio has on quench, volumetric efficiency, tumble and flame propagation. Even more important on the GDI, your dish in the piston plays a LARGE effect on the spray (and thus vaporization of fuel) from the DI which cools your pre-ignition in-cylinder temps.

Also, more air and more fuel (at the added few CC's) doesn't not mean more power. There is a lot more to an engine than that when you are talking volume changes that are this small. With the added volume, that can also mean more residual gas too, so you how have a lower % of your volume being fresh air and fuel.

With that being said, you also said that you would have lower temps with a lower compression ratio. With all things being equal, I would agree. However, as stated, not all things are equal. You may have a nice 'chunk' of your now being hot exhaust (residual gas).


...just telling the rest of the story
Good points
__________________

2000 Carbon Blue Toyota Celica GTS 152000 miles
(wont forget you)
2013 Argento Scion FR-S
2011 Infiniti G37x
carbonBLUE is offline   Reply With Quote
Old 01-12-2013, 09:25 AM   #60
hooman
Member
 
hooman's Avatar
 
Join Date: Dec 2012
Drives: GTS86
Location: Sydney
Posts: 14
Thanks: 0
Thanked 2 Times in 2 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
It's really a problem only in summer heat
hooman is offline   Reply With Quote
Old 03-12-2013, 08:06 AM   #61
MSTiFK8R
Senior Member
 
MSTiFK8R's Avatar
 
Join Date: Jul 2012
Drives: BRZ WRB
Location: Country of Bears
Posts: 336
Thanks: 257
Thanked 264 Times in 82 Posts
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Could anyone recall maximum psi proven which could be run without detonation on 93 \ stock motor \ upgraded fuel injectors&pump ?



What's the record by now?
@Visconti , John, what's your experience?

Last edited by MSTiFK8R; 03-12-2013 at 08:20 AM.
MSTiFK8R is offline   Reply With Quote
The Following User Says Thank You to MSTiFK8R For This Useful Post:
congiiee (04-06-2014)
Old 04-06-2014, 09:47 AM   #62
congiiee
Senior Member
 
Join Date: Aug 2012
Drives: WRB Subaru BRZ
Location: Virginia
Posts: 197
Thanks: 57
Thanked 62 Times in 31 Posts
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by MSTiFK8R View Post
Could anyone recall maximum psi proven which could be run without detonation on 93 \ stock motor \ upgraded fuel injectors&pump ?



What's the record by now?
@Visconti , John, what's your experience?
Anyone know what the max psi is on stock block? No E85
congiiee is offline   Reply With Quote
Old 04-06-2014, 09:53 AM   #63
ZionsWrath
Thanks
 
ZionsWrath's Avatar
 
Join Date: Apr 2013
Drives: BRZ
Location: NY
Posts: 4,163
Thanks: 5,989
Thanked 3,100 Times in 1,498 Posts
Mentioned: 38 Post(s)
Tagged: 3 Thread(s)
Necro master
ZionsWrath is offline   Reply With Quote
Old 04-06-2014, 09:59 AM   #64
MAPerformance
Senior Member
 
Join Date: Aug 2012
Drives: Asphalt FRS
Location: Cottage Grove, MN
Posts: 1,272
Thanks: 669
Thanked 981 Times in 540 Posts
Mentioned: 84 Post(s)
Tagged: 3 Thread(s)
Quote:
Originally Posted by congiiee View Post
Anyone know what the max psi is on stock block? No E85
Too many variables really, but I am running 11-12 on 93 with mine. The car seemed to like this the best with my small turbo. 15 an up, we did see two counts of knock. One below 4500rpm, and one about 6k. So we turned it back down. However, there is a member on here running 20psi on pump safely according to his tuner.
MAPerformance is offline   Reply With Quote
Old 04-06-2014, 10:48 AM   #65
woode
Boosted Member
 
woode's Avatar
 
Join Date: Dec 2013
Drives: 2013 Subaru BRZ
Location: Maryland, USA
Posts: 699
Thanks: 455
Thanked 464 Times in 246 Posts
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Garage
Send a message via MSN to woode
Quote:
Originally Posted by congiiee View Post
Anyone know what the max psi is on stock block? No E85

I am running ~22psi on stock internals on 93 octane, and there is still headroom there before it was showing knock. Been running it like this for a couple months now. Before that I was running 17psi.
FWIW, I am running straight 93. Not the "This gas may contain up to 10% ethanol" crap. How much of a difference that makes -

Now, I don't know how long it would hold up in a track setting. This is why I am building the motor though - I will probably stay about the same power (maybe a bit more), just with a bigger margin for error and better durability. I have plans for getting into going to the track by fall or maybe next spring at the latest.


To be honest, my biggest concern is cooling.. the engine seems to be doing fine (for the street) at these power levels. But again, 15 seconds of running thru the gears at 22psi and I am doing like 150mph, and thru the twisty back roads it doesn't see full boost for long at all so can't exactly say what it will do in a track environment where it is at the limits for a long period of time which creates a lot of heat.
__________________
2013 Subaru BRZ LTD 6MT DGM
2014 Subaru XV Crosstrek Hybrid TRG PG
2011 Honda CBR1000RR
2010 Subaru Impreza WRX PRM SSM
woode is offline   Reply With Quote
The Following 2 Users Say Thank You to woode For This Useful Post:
congiiee (04-06-2014), onzippy (04-06-2014)
Old 04-06-2014, 08:57 PM   #66
cdrazic93
Junior
 
cdrazic93's Avatar
 
Join Date: Aug 2013
Drives: a car
Location: Probably at school
Posts: 4,341
Thanks: 3,184
Thanked 2,512 Times in 1,502 Posts
Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
www.xcceleration.com/cr-boost%20101.htm

http://www.enginelogics.com/read-a-t...ompressor-map/
__________________
"Ah! What music! They could have never imagined, those pioneers who invented the automobile, that it would posses us like this, our imaginations, our dreams. Men love women, but even more than that, men love CARS!"-Lord Hesketh
cdrazic93 is offline   Reply With Quote
Old 04-06-2014, 10:14 PM   #67
onzippy
Senior Member
 
Join Date: Jan 2014
Drives: 2014 FRS
Location: Long Island NY
Posts: 117
Thanks: 43
Thanked 61 Times in 42 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Garage
Quote:
Originally Posted by woode View Post
I am running ~22psi on stock internals on 93 octane, and there is still headroom there before it was showing knock.
Your numbers make me feel so much better about running 8psi on mine.

Do you have any ecutek logs from round the town stops or dyno power runs to share? Id like to compare with what I see in mine. Thanks.
onzippy is offline   Reply With Quote
Old 04-06-2014, 10:28 PM   #68
congiiee
Senior Member
 
Join Date: Aug 2012
Drives: WRB Subaru BRZ
Location: Virginia
Posts: 197
Thanks: 57
Thanked 62 Times in 31 Posts
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by woode View Post
I am running ~22psi on stock internals on 93 octane, and there is still headroom there before it was showing knock. Been running it like this for a couple months now. Before that I was running 17psi.
FWIW, I am running straight 93. Not the "This gas may contain up to 10% ethanol" crap. How much of a difference that makes -

Now, I don't know how long it would hold up in a track setting. This is why I am building the motor though - I will probably stay about the same power (maybe a bit more), just with a bigger margin for error and better durability. I have plans for getting into going to the track by fall or maybe next spring at the latest.


To be honest, my biggest concern is cooling.. the engine seems to be doing fine (for the street) at these power levels. But again, 15 seconds of running thru the gears at 22psi and I am doing like 150mph, and thru the twisty back roads it doesn't see full boost for long at all so can't exactly say what it will do in a track environment where it is at the limits for a long period of time which creates a lot of heat.
That is insane. You have any videos? Dyno sheets?
congiiee is offline   Reply With Quote
Old 04-06-2014, 10:36 PM   #69
onzippy
Senior Member
 
Join Date: Jan 2014
Drives: 2014 FRS
Location: Long Island NY
Posts: 117
Thanks: 43
Thanked 61 Times in 42 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Garage
Quote:
Originally Posted by congiiee View Post
That is insane. You have any videos? Dyno sheets?
http://www.ft86club.com/forums/showt...ght=woode+dyno


He also has a dyno sheet if you look for it. I want tuning logs..
onzippy is offline   Reply With Quote
The Following User Says Thank You to onzippy For This Useful Post:
congiiee (04-06-2014)
Old 05-21-2014, 03:01 PM   #70
billwot
Senior Member
 
Join Date: Mar 2014
Drives: '11 Cayman , '14 Camry, '11 Tacoma
Location: Eastern NC
Posts: 509
Thanks: 57
Thanked 396 Times in 198 Posts
Mentioned: 5 Post(s)
Tagged: 1 Thread(s)
Quote:
Originally Posted by DrifterX View Post

Basically, Boost + Compression = Effective compression ratio.


So 10/14.7 = .68 *2 = 1.36 + 10.5 = 11.86. Which means you can actually boost more.
The relationship between boost and CR is multiplied, not added.

In your example, the calculation would be 1.68 X 10.5 = 17.64!

1 bar boost (approx. 14.7 psi) doubles effective CR. Obviously, if you double the density of the intake charge, you will double the effective CR.

"Effective Compression = ((Boost PSI / 14.7) + 1) * Current Static Compression Ratio"

Here is a simple calculator for determining effective CR:

http://www.gtsparkplugs.com/Effectiv...ssionCalc.html
billwot is offline   Reply With Quote
 
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Using Subarus other turbo Boxers as an idea, how much HP could a turbo BRZ/FR-S have? HitTheGas BRZ First-Gen (2012+) -- General Topics 12 02-21-2012 01:24 PM
Turbo FR-S Mino Engine, Exhaust, Transmission 24 12-16-2011 08:42 AM
Compression ratio 12.5:1. Bye-bye Super charger & Turbo build? fred_boosted Engine, Exhaust, Transmission 215 12-12-2011 07:23 PM
turbo yes BMWDAD BRZ First-Gen (2012+) -- General Topics 79 12-06-2011 12:58 AM
Geneva Preview: Techart to debut 911 Turbo, Turbo S vh_supra26 Other Vehicles & General Automotive Discussions 1 02-22-2010 06:20 PM


All times are GMT -4. The time now is 02:27 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
User Alert System provided by Advanced User Tagging v3.3.0 (Lite) - vBulletin Mods & Addons Copyright © 2024 DragonByte Technologies Ltd.

Garage vBulletin Plugins by Drive Thru Online, Inc.