Gsr Turbo?
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SnailOnARampage
Senior Member
the only way you would get 400 whp out of 10 psi on a gsr is to be driving it with a big ass intercooler in 80 below zero weather
SnailOnARampage
Senior Member
it doesnt have anything to do with air flow, it had to do with the post above that....saying that i understood teh difference between pressure and volume...im just a slow typer i guess
SnailOnARampage
Senior Member
in excess of 10k rpms you might be making 400 whp, but i swear you would not be making more than 2x stock torque at 14.7 psi. I know that with a honda, for each ft/lb you get out of it, you get about 1.5 hp, because of the rpm factor.
SnailOnARampage
Senior Member
yeah i know i use that equation all the time.
110 ft/lbs x 7600 rpms /5252 = 159.2 hp
111 ft/lbs x 7600 rpms /5252 = 160.6 hp
160.6 - 159.2 = 1.4 hp per ft/lb of tq in a honda
hence that is true.
110 ft/lbs x 7600 rpms /5252 = 159.2 hp
111 ft/lbs x 7600 rpms /5252 = 160.6 hp
160.6 - 159.2 = 1.4 hp per ft/lb of tq in a honda
hence that is true.
SnailOnARampage
Senior Member
Now I swear, unless you either make your engine displace like 2.6 liters, or increase your rpms to 10k, you can not make 400 whp at 10 psi on ANY turbo.
SnailOnARampage
Senior Member
Now all of those ideas are based on my *assumption* that the relationship between actual number of oxygen molecules and air pressure is linear, which I have no clue either way, it just makes sense to me that it would be linear.
SnailOnARampage
Senior Member
A stock GSR displaces: .06346046 cf/revolution. assuming that there is NO loss due to restriction or whatever, that will equate to 481.9 cf/m @ 7600 rpm on the stock GS-R engine.
A 84 mm GSR displaces .06826325 cf/revolution. assuming there is no loss due to restriction, that is 593.9 cf/m @ 8700 rpm. Inorder to actually have the power peak at 8700 you will need some seriously bad ass cams/valvesprings.
That all equals out to the bored gsr approximately 1.23 x the hp at the peak. That number there is not including the benefits of port/polishing and things like that. Lets add an additional 10 percent for better flow rates due to a nice polished head. That brings the bored out one to 1.353 x as good as the regular GSR @ their power peaks. Lets go ahead and add another 5% for good tuning. Its now at 1.42 x170 equalling 241 hp to the crank. Now put a turbo on there that is able to push all of the cf/m @ 10psi and you have you *very estimated* 410 crank hp, which will leave you at about 375 whp.
Now lets go and do this a slightly different way.
1933/1797 = 1.08 ...the bored gsr has a minimum of 1.08x the torque of the regular GSR based solely on displacemement. Multiply that by 127 and you get 137 ft/lbs. Lets add another 10 on there for good measure/good tuning/whatever, which brings us to a fairly normaly torque number for a heavily modified GSR....145 ft/lbs. Multiply 145 x 1.7 (10psi) and you get 250 ft/lbs. 250 x 8700/5252
(assuming no loss after torque peak) and you get 412 crank HP.
Yes you are actually getting very close to 400 whp, and its even going by my "flawed" and linear standards.
Okay now for the turbo part. I know you've told me that I am wrong like 6 times, but I still haven't heard a good reason as to why I am.
I was actually wrong in previous posts (it was very late) about my numbers of cf/m...but here are the revised ones.
Assuming those cf/m numbers for the engines are above, with your GSR setup, you will need a turbo that can push a little more than 600 cf/m @ 10 psi...which should be the same amount of oxygen as 1000 cubic feet of uncompressed air (provided its the same temp). If you get a turbo that can only push 500 cf/m @ 10 psi you will only be putting the equivalent of 833 cf of air into the engine,.
Okay, so seeing all that, you have 2 diff turbos. a t66 and a t88. we'll pretend that the t66 can push 500 cf/m @ 10 psi and the t88 can push 600 cf/m @ 10 psi.
On the bored GSR running 10 psi the t88 would be ideal, because the amount of air it can move is almost exactly what the bored out engine uses at 8700 rpm.
The t66 would be ideal for the stock gsr engine @ 10 psi because the stock GSR will be able to accept almost exactly how much air the turbo can pump into it.
Now, if you put the t88 on the stock gsr, you would be creating extra drag and lag which is un-necessary for that engine running at 10 psi. The t88 would only do any better on the stock GSR if you set the wastegate to 13 psi or something.
Now when you go over to the bored GSR will be getting more power with the t88, and the t66 will only be producing something like 8 psi at full throttle at the power peak (even though the waste gate is set to 10). However, if you set the waste gate down to 7 psi for both turbos, the t66 would be faster again.....
So.... with 10 psi reading at the map sensor at full throttle at a given rpm at a given temperature, the power output will actually be greater with the smaller turbo
A 84 mm GSR displaces .06826325 cf/revolution. assuming there is no loss due to restriction, that is 593.9 cf/m @ 8700 rpm. Inorder to actually have the power peak at 8700 you will need some seriously bad ass cams/valvesprings.
That all equals out to the bored gsr approximately 1.23 x the hp at the peak. That number there is not including the benefits of port/polishing and things like that. Lets add an additional 10 percent for better flow rates due to a nice polished head. That brings the bored out one to 1.353 x as good as the regular GSR @ their power peaks. Lets go ahead and add another 5% for good tuning. Its now at 1.42 x170 equalling 241 hp to the crank. Now put a turbo on there that is able to push all of the cf/m @ 10psi and you have you *very estimated* 410 crank hp, which will leave you at about 375 whp.
Now lets go and do this a slightly different way.
1933/1797 = 1.08 ...the bored gsr has a minimum of 1.08x the torque of the regular GSR based solely on displacemement. Multiply that by 127 and you get 137 ft/lbs. Lets add another 10 on there for good measure/good tuning/whatever, which brings us to a fairly normaly torque number for a heavily modified GSR....145 ft/lbs. Multiply 145 x 1.7 (10psi) and you get 250 ft/lbs. 250 x 8700/5252
(assuming no loss after torque peak) and you get 412 crank HP.
Yes you are actually getting very close to 400 whp, and its even going by my "flawed" and linear standards.
Okay now for the turbo part. I know you've told me that I am wrong like 6 times, but I still haven't heard a good reason as to why I am.
I was actually wrong in previous posts (it was very late) about my numbers of cf/m...but here are the revised ones.
Assuming those cf/m numbers for the engines are above, with your GSR setup, you will need a turbo that can push a little more than 600 cf/m @ 10 psi...which should be the same amount of oxygen as 1000 cubic feet of uncompressed air (provided its the same temp). If you get a turbo that can only push 500 cf/m @ 10 psi you will only be putting the equivalent of 833 cf of air into the engine,.
Okay, so seeing all that, you have 2 diff turbos. a t66 and a t88. we'll pretend that the t66 can push 500 cf/m @ 10 psi and the t88 can push 600 cf/m @ 10 psi.
On the bored GSR running 10 psi the t88 would be ideal, because the amount of air it can move is almost exactly what the bored out engine uses at 8700 rpm.
The t66 would be ideal for the stock gsr engine @ 10 psi because the stock GSR will be able to accept almost exactly how much air the turbo can pump into it.
Now, if you put the t88 on the stock gsr, you would be creating extra drag and lag which is un-necessary for that engine running at 10 psi. The t88 would only do any better on the stock GSR if you set the wastegate to 13 psi or something.
Now when you go over to the bored GSR will be getting more power with the t88, and the t66 will only be producing something like 8 psi at full throttle at the power peak (even though the waste gate is set to 10). However, if you set the waste gate down to 7 psi for both turbos, the t66 would be faster again.....
So.... with 10 psi reading at the map sensor at full throttle at a given rpm at a given temperature, the power output will actually be greater with the smaller turbo
SnailOnARampage
Senior Member
The thing with turbos is, they do not actually cause the engine to accept more cf/m. They just pump in air at the same rate...600 cf/m for example, but that air is compressed so that it is more dense, therefore yielding more oxygen to burn. And once again...600 cf compressed at 10 psi above ambient air pressure has the same o2 content as 1000 cf of uncompressed air
SnailOnARampage
Senior Member
at 10 psi (which is what I would consider to be the upper limit of boost an engine can accept and still be semi reliable on stock internals) you would make about 260 whp, if your turbo can push the appropriate amount of air into the engine. I havent actually looked up the flow rates for any turbos yet, so I can't tell you what will do that and what wont. Just make sure to run synthetic oil on the engine, so you arent as likely to bend/break/throw any rods. As for the health of your pistons, the synthetic oil will help too, but it will not do a damn thing to save you if you dont have good fuel management.
SnailOnARampage
Senior Member
Can you tell me why 600 cf of air compressed at 10 psi at 70 degrees will not have the same oxygen content as 1000 cf of air uncompressed at 70 degrees? Or better yet, why 1000 cf of uncompressed air would not have the same o2 content as 500 cf compressed to 14.7 psi?
heterosapian
Senior Member
Ractive, Ive seen a guy put down 280whp with a gsr on 13?psi with just DSM injectors ( heres the install page, not the dyno, http://www.homemadeturbo.com/tech_projects...tors/index.html ) and an safc for fuel control, just make sure you cool the shit out of everything. The profec B is bar none the best boost controler ive come across in my experience with dsms.
Snail, psi does not dictate the volume of air. Please, understand this. Half of your posts have been arguing against physics. Sol's bicycle tire example was perfect. More pressure means more heat, not more air. Go ask Boyle.
Yes, you can compress a given amount of air into a smaller space. No, you cannot create matter. The number of air molecules you start with before compression is not going to increase. Sol's point, and mine, is that a larger turbo pulls in more air to begin with, therefore pushing more air after compression than a smaller turbo. The reason a given turbo will move more cfms at higher psi is because it has bigger/steeper/clipped/taller fins to compress all that air, and a bigger compressor housing to move it all through, not simply because more psi = more cfm. And Sol, Id be well impressed to see 400 hp at 10psi only because its hard to believe that a gsr, even one at almost 2liters, can move enough exhaust to get the turbine spooling on a turbo that can produce that many cfms at 10psi
Snail, psi does not dictate the volume of air. Please, understand this. Half of your posts have been arguing against physics. Sol's bicycle tire example was perfect. More pressure means more heat, not more air. Go ask Boyle.
Yes, you can compress a given amount of air into a smaller space. No, you cannot create matter. The number of air molecules you start with before compression is not going to increase. Sol's point, and mine, is that a larger turbo pulls in more air to begin with, therefore pushing more air after compression than a smaller turbo. The reason a given turbo will move more cfms at higher psi is because it has bigger/steeper/clipped/taller fins to compress all that air, and a bigger compressor housing to move it all through, not simply because more psi = more cfm. And Sol, Id be well impressed to see 400 hp at 10psi only because its hard to believe that a gsr, even one at almost 2liters, can move enough exhaust to get the turbine spooling on a turbo that can produce that many cfms at 10psi
heterosapian
Senior Member
Synthetic oil... 
. Oh and snail, not to be a dick or anything, but do you actually have any experience with turbos?
. Oh and snail, not to be a dick or anything, but do you actually have any experience with turbos?
Originally posted by heterosapian@Mar 17 2003, 08:16 PM
Synthetic oil...
why do you say that?, all ive ever used in any of my cars is synthetic oil, and ive never had problems. my cars, including my B18C wich i have in my car now, have actually ran better with synthetic.
SnailOnARampage
Senior Member
Okay this is a waste of my time. Nobody has actually backed up any claim that I'm a dipshit. If im arguing against physics, please enlighten me. Why not go do some research about synthetic oil and save me the trouble of explaining it for the third time? Why not go look up all the dyno charts you can find, and when you come across one that proves me wrong, show it to me.
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