boost and compression ratio
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- Fourth Gear
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boost and compression ratio
could anyone give me an idea or pointer to a place to look/person to talk to figure out a comparison between boost and compression ratio.
is higher boost = to raising compression? or am i just way off base?
for examples sake, is adding 8 psi of boost to a n/a motor w/9.5:1 compression the equivelant of raising an identical but N/A motor C:R to, say, 13:1?
i just used those values to illustrate my scenario i have no idea what they actually would be.
greg
is higher boost = to raising compression? or am i just way off base?
for examples sake, is adding 8 psi of boost to a n/a motor w/9.5:1 compression the equivelant of raising an identical but N/A motor C:R to, say, 13:1?
i just used those values to illustrate my scenario i have no idea what they actually would be.
greg
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- Knowledgeable
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BAM!
http://www.smokemup.com/auto_math/eff_cr.php
http://www-unix.oit.umass.edu/~tcroy/ar ... tivecr.htm
http://home.dmv.com/~carlb/sc/ecr-chart.html
http://www.rapidline.com/calc/turbo/pctcomp.htm
http://www.autocomponenti.com/boosted_t ... ession.htm
searched google.com for "effective compression ratio"
http://www.smokemup.com/auto_math/eff_cr.php
http://www-unix.oit.umass.edu/~tcroy/ar ... tivecr.htm
http://home.dmv.com/~carlb/sc/ecr-chart.html
http://www.rapidline.com/calc/turbo/pctcomp.htm
http://www.autocomponenti.com/boosted_t ... ession.htm
searched google.com for "effective compression ratio"
-Jason Grahn
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- Fourth Gear
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so what is the highest C/R i can get away with in a ej22 N/A while still running the 92 octane swill i'm stuck w/here in ND? if i fugure out what the effective C/R is on a stock/mildly modified ej22t that still runs on pump gas i should be able to get away w/a similar C/R on my N/A motor.
i am getting closer to trying my phaseII ej25 block w/ej22 heads and want to do it as right as possible. of course i should just get a second set of heads and just try it rather than use my good 2.2 heads in case it blows up real good.
i am getting closer to trying my phaseII ej25 block w/ej22 heads and want to do it as right as possible. of course i should just get a second set of heads and just try it rather than use my good 2.2 heads in case it blows up real good.
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- Vikash
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I don't think the effective CR on an EJ22T will give you a good idea of how far you can push a non-turbo EJ22; there's a lot of other stuff going on that affects knock tendency (high temperatures, increased fueling, retarded ignition, etc).
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
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- Fourth Gear
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Bigger pump, bigger injectors, and adjust the pressure.greg donovan wrote:so i would need more fuel in a high CR motor?
any tips on how to do this?
Ingnition timing can be changed with piggyback computers or a standalone.how would i change ignition timing? retarding the ignition timing will help to prevent what exactly?
-Jason Grahn
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how much more flow can i get out of the stock injectors? what do they flow at now?
how much more pressure can i squeeze out of the stock system w/a rising rate fuel pressure regulator? what is the fuel pressure now?
would turbo injectors and fuel pump be enough?
any tips on a piggyback computer to change ignition timing? and how necessary would that be?
how much more pressure can i squeeze out of the stock system w/a rising rate fuel pressure regulator? what is the fuel pressure now?
would turbo injectors and fuel pump be enough?
any tips on a piggyback computer to change ignition timing? and how necessary would that be?
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- Knowledgeable
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Emanage for piggyback. Necessity is base off your end goals. That's something you'll need to decide.greg donovan wrote:how much more pressure can i squeeze out of the stock system w/a rising rate fuel pressure regulator? what is the fuel pressure now?
rising rate bad. Adjustable good. Look for aeromotive fuel pressure regulators.Depends on high you've planned.would turbo injectors and fuel pump be enough?
any tips on a piggyback computer to change ignition timing? and how necessary would that be?
-Jason Grahn
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- Fourth Gear
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just found your link to the aeromotive stuff. looks spendy and cool. as for my goals i just want a little more power. and this project is basically free. unless i start adding on stuff to make it more reliable. what is more important fuel or timing?
if fuel is more important what is more important AFPR, higher flow pump or injectors?
if i had to spend alot of money i would not do this motor stuff i would buy a KAAZ front lsd for my car.
if fuel is more important what is more important AFPR, higher flow pump or injectors?
if i had to spend alot of money i would not do this motor stuff i would buy a KAAZ front lsd for my car.
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They are both quite important and must be considered together when building up a car.greg donovan wrote:what is more important fuel or timing?
I hate to say this, but i find myself repeating it more and more the longer i'm in the car community: If you don't have excess to spend, then do not undertake the project. I haven't known one project to NOT have creeping costs with it, a little piece here and a little piece there and some fittings here and some new hoses here... It all adds up. No money = no modification.if i had to spend alot of money i would not do this motor stuff i would buy a KAAZ front lsd for my car.
-Jason Grahn
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- Fourth Gear
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the appeal of this project is that it could be free. it is for my rallyx car as i will soon be buying another street car. or i will pull the good ej22 and get some used heads and slap them on the ej25 and see what happens in the name of science an the pursuit of more power. and if it blows up then we will all know what will happen and how far we can go wrt to CR.
From all the stuff I have seen......too much timing seems to be the more common cause of problems because people don't want to deal with it.....ie piggy backs, tuning, etc. Fuel seems to be something that is typically taken care of....people add larger pumps, larger injectors, rrfpr......but even then.....you really need some form of additional control for those injectors other then the stock ecu.
Josh
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm
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- Fourth Gear
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when you say timining. do you mean cam or ignition timing? since the emange controls fuel what would be a good piggyback for retarding ignition timing? or am i missing some of the features of the emanage. i really have limited knowledge in this are and really appreciate everyones help. this is a project that i will have a master tech. helping me with. more likely it will be me helping him.
emanage can control timing and do a lot of other things too, if you either get the emanage laptop connection thing or a profec eo1 boost controller/emanage programmer/datalogger
Micum
91 Legacy Turbo Sport - 94 JDM EJ20G
97 Legacy 2.5 GT - mod'd
93 Impreza L AWD (sold)
97 Legacy 2.5 GT (deceased)
98 Legacy Outback (sold)
91 Legacy Turbo Sport - 94 JDM EJ20G
97 Legacy 2.5 GT - mod'd
93 Impreza L AWD (sold)
97 Legacy 2.5 GT (deceased)
98 Legacy Outback (sold)
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- Knowledgeable
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If you have to pull too much ignition to run a higher CR it may negate any power gain unless you put in higher octane and can bring back the timing. These engines are already relatively high CR, so I don't think there's very far to go before you'll be getting retardation unless you spend good money on tuning, but there goes your free deal... If you had higher octane available it would be a lot more effective.
Steve
Steve
Midnight in a Perfect World on Amazon or order anywhere. The first book in a quartet chronicling the rise of a man from angry criminal to philanthropist. Midnight... is a distopic noirish novel featuring 'Duchess', a modified 1990 Subaru Legacy wagon.
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- Fourth Gear
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I was mainly referring to ignition timing. The n/a cars have a lot more ignition timing then the turbo cars.....so if you slap a turbo on a n/a car....you need keep some of that in check.
Josh
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm