N/A power confusion

[SILINC3R]

ok i am kind of confused and scared at the same time. i read the sticky on what to do with our N/A motors to get more power out. that is exactly the steps i needed and have done some and doing more as i type. but then i cam across the tread about the dyno posts and my heart sank like the Titanic. when i first got my 90 LS i messed with the idea of a swap or going to turbo for help. then i said screw it and leave in the nice N/A motor with 242XXX miles since it is still rockin. but these dyno posts, maybe i am reading them wrong. i have been wanting to do a pull for the last month but if i go do it and see results like these i may seriously cry. now i know my car has a lot of hours and miles on it and i know i wont have the stock HP or maybe close to. stock was 135 i belive. but why was i seeing 101 and 117. if i got mine dynoed and got 101 i fell like i would just die. my plan was to get like 170 to the most 200 after i get done with the car. i would like to think i have atleast 120 as i type. but now im afraid. i have done a lot of work to this car and if i see bad results i will fell like it has been for nothing. maybe ill call it quits and get a dang honda. :smt022 please help

[rougeben83]

drivetrain loss as engine power goes through the gearbox, axles and to the wheels. Usually 15-20% on 2wd cars, 25% and above on AWD/4wd cars. Dynos read from the wheels, ie whp vs bhp or crank hp.

[ScaryFatKidGT]

yeah 135 is stock crank HP for the 2.2 right? and 165hp for the 2.5

what have you all done to the car?

[impreza_GC8]

Mods to N/A Subaru motors are more to increase the fun factor than actual power. Unless you go turbo, you are still N/A. Dyno's read power at the wheels so your engine is making 20% more power than what the dyno reads. Most likely, due to the age of your engine, all your mods have brought the car back up to the hp it made brand new. Don't expect to be blown away. I'd say at the very most every bolt on you can do to an N/A engine will only net you 15hp total. For that reason I don't dyno my 2.5RS. It is very competitive on the AutoX course and is a blast to drive. Who cares about a hp number.

[ScaryFatKidGT]

well you can get some pretty good HP if you get some cam regrinds and then you could get your heads done while there off not to much money but still more than just intake, exhaust and pulleys

[SILINC3R]

yeah 135 is stock crank HP for the 2.2 right? and 165hp for the 2.5

what have you all done to the car?

yes that is correct. i have done a CAI, A/C delete, and a muffler. doing headers and a full exhaust when i get the time and money. pulley set is on the way. and depending on what these yeild me i may go into the engine

[SILINC3R]

Mods to N/A Subaru motors are more to increase the fun factor than actual power. Unless you go turbo, you are still N/A. Dyno's read power at the wheels so your engine is making 20% more power than what the dyno reads. Most likely, due to the age of your engine, all your mods have brought the car back up to the hp it made brand new. Don't expect to be blown away. .

im would be more than ok if i got the stock HP back. how do you mean blown away. i know that i would have over that. and i want the fact that i am an N/A to stay. i think that would be cool if i could achieve 150 before i had to open the engine up with 244XXX miles on it

[Piddster]

Your '90 2.2L was rated at 130 chp stock and the SS was 160 chp.


A few years ago Matt Monson was messing around with his '99 or '00 RS. He added an EL exhaust manifold, Cobb's "spicy" cams, some home porting, an intake, a pulley, and was making just about 157whp, IIRC. That is on a 2.5L, with much higher flowing heads, and higher compression that you have.


When you say 150, do you mean whp? If so, there is absolutely no chance of gaining 70hp without going into the motor, especially with relatively low compression and heads that flow like coffee stir sticks.

An intake will likely do more harm that good unless you have a way of tuning the motor. People have shown, on the BBS, that even taking out the silencer can bmess with the MAF sensor in a bad way.


A friend of mine makes about 200whp with a factory turbo manifold, an ebay turbo, a RRFPR, and a topmount. And has done so for almost three years. Granted, he gets poor mileage, but you gotta pay to play.

[Reason]

Getting only 15whp net from every bolt on is a very low estimate. I'm pretty sure I will match whp to my GT with a few bolt on with my L. No internal work done and more than double the mileage. As for drivetrain lost in AWD Subarus I estimate around 33%.

Don't get discouraged till you see the numbers. I would tend to that exhaust though, you want see much of an improvement from just an upgraded muffler.

[HeresMyMind]

my 2.5 gt dyno's 109corrected whp. and i have a buttload of mods(Borla headers, stromung high flow cat, stromung catback, SRI intake, ignition.. the best thing u can do it do a great tune up.

if your leaking oil anywhere get it fixed. new plugs wires filters. stuff like that helps in the long run. clean up your grounds. and so forth.

-B

[StatGSR]

here is my take on NA tuning, you can toss all the bolt-ons at it all day long, you "might" feel like your car is making more power, and you can still spend up several grand for nothing much more than some fun noises and a happy butt dyno.

When it comes right down to it, if you wana see some really differences you have to change atleast 1 of these three things (the more you change the better). Displacement - Increase it, Compression - Increase it, RPMs - Increase it.

uber dumbed down version cause im lazy

Increased displacement will net you more torque period. Power is derived from torque and RPMs and will therefore increase
https://sl-i.net/FORUM/images/imported/2009/03/7e62b9d244cb0c557e63a7df5c111cdbpng-2.jpg

Compression, the more compression you can run before creating detonation will net you more power, period.

increased Redline, like shown, if you can increase your rpms and STILL maintain torque (which typically begins to drop at the end of the engines powerband), you will net more power.

I will also not that with all of these proper tuning will need to be done as well as consideration to flow through the heads.


which leads me to why im putting a 3.3 in my wagaon haha.

[SILINC3R]

ok so i am lost with all of these ratings.
HP
WHP
BHP
CHP

so 130 CHP is what in HP and so on

thanks i just dont understand why there are so many

[KAG]

WHP = Wheel Horsepower
BHP = Brake Horsepower
CHP = Crank Horsepower

As stated numerous times in this thread already, whp on an AWD car is usually 20-30% less than the chp the car was rated at from the factory.

Just because your car stock had "130hp" does not mean that you're getting 130hp at the wheels. If you read Reason's Member's Ride thread linked in his sig, you will see that his 98 L produced only 95hp at the wheels even though the Phase I ej22 is rated is 137chp.

Make sense?

[StatGSR]

Brake horsepower is measured on a chassis dyno which does not include the wheels on the car (google it).


yea no it its not, your talking about something like a dyno pack, and no thats not what BHP is, its just like crank hp. its an engine power rating (from an engine dyno) minus accessories and transmission.

[SILINC3R]

Just because your car stock had "130hp" does not mean that you're getting 130hp at the wheels. If you read Reason's Member's Ride thread linked in his sig, you will see that his 98 L produced only 95hp at the wheels even though the Phase I ej22 is rated is 137chp.

kind of makes since, understand that these cars arent just losing power it is just rated differently

[ScaryFatKidGT]

OK FIRST HP is horse power it is a general term used to mesure work. BHP is base horse power and is the same as CHP its the hp the engine makes before going threw all the drive components and getting 2 the wheels or horse power mesured at the crank BHP=CHP. WHP is the horse power mesured at the wheels after going threw all the drive components and is always lower than BHP or CHP but more so on AWD and 4WD cars

SECOND there is 2 ways to make more power out of an engine
1. increase compretion getting more power out of the fuel and air or
2. simply put burn more fuel and air

pullys flywheels and exhaust dont make power they just allow the engine to operate more efficently by redusing wait or by getting the exhaust gases out smoother and with less force, therefor neting more power

are cars are already at a 10-1 comprestion RATIO increasing it at all you will need premium fuel and increasing it past 11-1 will make you car not very streetable and you wont meet emitions although the car would be street legal in every other way

intakes mainly allow air to enter the engine easier they dont really get much more air into the engine which is why they only make about 5 more hp

turbos increas the amout of air into the engine therefor allowing more fuel in (with bigging injectors ect.) but they also increase compretion which is why almost all turbo cars take premium fuel and run at lower compretion ratios that N/A cars

increasing rpm's allows the engine to burn fuel faster and therefor makes more power but cams, stiffer valve springs and Engine manegment are need to do this

increasing displacment (a bigger engine), cams, and head, valve and intake manifole/TB porting all allow more air and or fuel to get in the engine and to be burned getting more power.

with all that said theres one more thing (I'm not 100% sure on the NOS stuf so correct me if you want)
Nitrousoxide/NOS about 70% of the power of nitrous comes from cooling the whole intake charge and everything almost 20-30 degrees instantly, allowing lots more air in and the other 30 or so % is from it acting as a catalist, the OXIDE part of the nitrouse oxide, oxygen molecules, separate from the nitrogen and give even more air into the engine (air is basicaly just nitrogen and oxygen anyway)

[StatGSR]

BHP is base horse power

BHP FAIL

http://en.wikipedia.org/wiki/Horsepower

as mentioned earlier, its Brake Horsepower

[SILINC3R]

for sure got it now. thanks

[ScaryFatKidGT]

Brake horsepower (abbreviated bhp) is the measure of an engine's horsepower without the loss in power caused by the gearbox, generator, differential, water pump, and other auxiliary components such as alternator, power steering pump, muffled exhaust system, etc. "Brake" refers to a device which was used to load an engine and hold it at a desired RPM. During testing, the output torque and rotational speed were measured to determine the "brake horsepower". Horsepower was originally measured and calculated by use of the indicator (a James Watt invention of the late 18th century), and later by means of a De Prony brake connected to the engine's output shaft. More recently, an engine dynamometer is used instead of a De Prony brake. The output delivered to the driving wheels is less than that obtainable at the engine's crankshaft.<<from wikipedia

well i know car and driver has refered to the manufacturs HP rating as base horse power

but theres really no difference either way "BHP" is the same as CHP and is the HP the engine makes before going threw every thing. We were just arguing about what the acranim (spell?) stood for, its the same thing

[SILINC3R]

well my head gaskets finally went on the car after 245XXX miles and 19 years of use. i hoping to get it Dynoed afterwards to see were it will be. wish i had done it a while ago so we could see how much of a difference there will be if any

[ScaryFatKidGT]

if ur head gaskets went and you get it fixed power shouldn't change much from before the main MILES=power loss is the piston rings wearing out

[99gtlimited]

Unless you go turbo, you are still N/A.

really??? :smt017 :smt017 haha

actually there are other types of forced induction but turbo's are the best for the cost.

this thread is getting out of control...

[impreza_GC8]

^ I can't put it any simpler than that! If you are trying to do an N/A build, you're just chasing a dream.
A notable exception would include the Wombat Racing H6 swapped Impreza.

[StatGSR]

^ yea, im thinking my h6 wagon will be pretty fun haha