M
Thanks Jeff C
How much power at alt M1100T?
- Thread starter Jimb
- Start date
Y
M
If you guys can't tell the difference between PSIG and PSIA then you are in trouble and should leave the tough stuff to AC. Those are some fancy formulas up above but you are making this way more complicated and inaccurate than it needs to be. 12 PSIG is 12 PSIG no mater if you are at sea level or at 10,000 feet your ambient pressure will not affect the final pressure in your cylinders if your boost gauge is reading 12 PSIG.
I will say it again as some will not get it the first time. If at sea level your boost gauge is reading 12 PSIG, your cylinders will have 12 PSIG in them. If at 10,000 feet your boost gauge is reading 12 PSIG, your cylinders will have 12 PSIG in them. It is very simple. No mater how you look at it 12 PSIG is 12 PSIG is 12 PSIG. If your boost tee can automatically compensate for elevation changes then you will never have to manually adjust your boost tee to compensate. And yes your compressor will be spinning faster to achieve the 12 PSIG at 10,000 feet but it will still only be 12 PSIG in your cylinders. To say that you will have to run 16 PSI to make up for ambient pressure changes is just........I can't think of a nice word to put there so I will leave it blank. Thank you for the mind numbing read.
I will say it again as some will not get it the first time. If at sea level your boost gauge is reading 12 PSIG, your cylinders will have 12 PSIG in them. If at 10,000 feet your boost gauge is reading 12 PSIG, your cylinders will have 12 PSIG in them. It is very simple. No mater how you look at it 12 PSIG is 12 PSIG is 12 PSIG. If your boost tee can automatically compensate for elevation changes then you will never have to manually adjust your boost tee to compensate. And yes your compressor will be spinning faster to achieve the 12 PSIG at 10,000 feet but it will still only be 12 PSIG in your cylinders. To say that you will have to run 16 PSI to make up for ambient pressure changes is just........I can't think of a nice word to put there so I will leave it blank. Thank you for the mind numbing read.
Y
J
I don't want to jump too hard on this one if you don't understand but yes you do have to make 16.5 psi at the gauge if you want to sea level hp of 177 at 10000ft, whereas 12 psi at the gauge makes 177hp at 0ft. The hp is dependent on manifold pressure as the sum Atmospheric plus Boost pressure.
http://old.2-stroke-porting.com/altiden.htm
Last edited:
H
Wow. Somebody needs to figure this pressure thing out! Do you know how a boost guage works? I agree 12 psig is 12 psig no matter where you are at....as long as it is a vented guage reading that 12psig. My powerstroke runs 20 PSIG no matter what elevation I am at. Thinner air just closes the wastegate a little more, turbo spins faster....same power, minus a little more heat generated.
That is some funny **** right there!
M
:face-icon-small-ton:laugh::hug:
opcorn::kiss::ranger::kev::juggle::wave::flypig::yo::washing:
opcorn::kiss::ranger::kev::juggle::wave::flypig::yo::washing:
So in summary, you want a Manifold Absolute Pressure Gauge to know what the actual pressure is.
Just like they have been using in turbocharged and supercharged airplanes for the last 70+ years
OK...I guess I need to qualify "motors are similar". Meaning, they perform an identical cycle. Yes, I get it, they have different parts and configurations.
As for the PSI thing...I can't tell if mynewusadalmao is being serious. You have two types of pressure: absolute and gauge. Absolute is what the atmosphere naturally maintains. Gauge is anything beyond that and it is relative. Absolute at sea level is 14.7PSI. So, if you boost 13 lbs, you are at 27.7PSI at the intake. At 10k ft, you have 10.2 absolute. So, to make 27.7 absolute, or the same pressure and power, in theory, you need 17.5PSI gauge.
Also, oxygen at elevation is still at the same ratio to the other gases (mainly Nitrogen) as at sea level...it's just less dense. So, if you compress it more you have the same oxygen level (in theory but it will vary).
So, yes, you do need more PSIG at elevation than sea level to make similar power.
As for the PSI thing...I can't tell if mynewusadalmao is being serious. You have two types of pressure: absolute and gauge. Absolute is what the atmosphere naturally maintains. Gauge is anything beyond that and it is relative. Absolute at sea level is 14.7PSI. So, if you boost 13 lbs, you are at 27.7PSI at the intake. At 10k ft, you have 10.2 absolute. So, to make 27.7 absolute, or the same pressure and power, in theory, you need 17.5PSI gauge.
Also, oxygen at elevation is still at the same ratio to the other gases (mainly Nitrogen) as at sea level...it's just less dense. So, if you compress it more you have the same oxygen level (in theory but it will vary).
So, yes, you do need more PSIG at elevation than sea level to make similar power.
C
I am just a flatlander But For my Apex to pull the same weights In Minnesota As at 10000 ft I needed to run at least 17 lbs at altitude where I ran 12 in Minnesota. Easy adjust !
F
school is out!!
i am now for sure and for certain that i know nothing or less than i did about something i thought i knew very little about before reading this... thanks guys.:face-icon-small-con
i am now for sure and for certain that i know nothing or less than i did about something i thought i knew very little about before reading this... thanks guys.:face-icon-small-con
Does the boost guage show zero at any altitude.
If that the case I can buy that you need more boost at altitude.
If I have understand it right you need too raise the boost more at altitude. But the presure in the mainfold is the same.
Boost pressure= the rise in pressure from atmosphere.
Mainfold pressure= the pressure in mainfold. (where you should see som minus reading at no boost)
btw, what pressure should one ride in the floatshocks at high altitude?
If that the case I can buy that you need more boost at altitude.
If I have understand it right you need too raise the boost more at altitude. But the presure in the mainfold is the same.
Boost pressure= the rise in pressure from atmosphere.
Mainfold pressure= the pressure in mainfold. (where you should see som minus reading at no boost)
btw, what pressure should one ride in the floatshocks at high altitude?
Does the boost guage show zero at any altitude.
If that the case I can buy that you need more boost at altitude.
If I have understand it right you need too raise the boost more at altitude. But the presure in the mainfold is the same.
Boost pressure= the rise in pressure from atmosphere.
Mainfold pressure= the pressure in mainfold. (where you should see som minus reading at no boost)
btw, what pressure should one ride in the floatshocks at high altitude?
You need to turn your rear float up approx 3 psi per # of boost, but as you go higher, you can turn it down 1 psi per 1000 feet. So basically, you're going to need to turn up the boost 1/3 # per 1000 to keep things equal.
S
G
The factory ecu on the cat turbo automatically targets 170kpa absolute manifold pressure. At my elevation of about 1100ft, this is about 12 psig. At 9500 ft, it is about 16.5 psig for the same absolute manifold pressure. Actual (uncorrected) hp is only slightly reduced due to the elevated intake temps and the same clutching from low elevation works fine. With free flowing exhaust (D&D Barker, Silent choice, or straight pipe) the stock turbo appears capable of maintaining up to about 190 kpa at 9500ft elevation. Even at stock boost levels, opening up the exhaust is a huge power gain. With stock muffler, the stock pressure of 170kpa is probably about it at 10,000ft. When operating on the edge of the compressor map, ambient temp also has a huge influence, with the turbo capable of much more in colder air. One thing for the non-turbo guys to remember is that the corrected hp (how you would compare to an n/a or any other motor) goes way up as you maintain constant absolute pressure at higher elevations. So when your stock boost 1100t is at 170 kpa at 10,000ft, the hp is correcting to well over 200hp. We (D&D/Boondocker) have been testing these motors since 2008, and I feel confident that most pump gas riders will be fine with the stock turbo to 10,000ft. Those running race fuel (or meth injection) boost levels will benefit more from a larger turbo.
Last edited:
G
Just to give some idea of the capabilities of this engine/turbo. We have made well over 300hp at sea level, simply turning up the boost. The only hardware mod being replacing the muffler with a straight pipe, shimming the wastegate and adding a Hijacker. Completely stock turbo, intercooler, charge tubes, engine, etc. Makes 30+ psi!! Have yet to see a turbo failure from the obvious overspeed.
Yeti, that 140mph was back in 08. In 2010 we went 147mph (8.57 sec 1/4 mile, asphalt) with bone stock motor/turbo/intercooler setup.http://www.youtube.com/watch?v=OCK_JQuHCP4
This setup also holds the 1000ft nssr record for a stock turbo 1100t at 131mph. Also went 162 mph (1/4 mile, asphalt) back in 09, with bigger turbo and cams.
Yeti, that 140mph was back in 08. In 2010 we went 147mph (8.57 sec 1/4 mile, asphalt) with bone stock motor/turbo/intercooler setup.http://www.youtube.com/watch?v=OCK_JQuHCP4
This setup also holds the 1000ft nssr record for a stock turbo 1100t at 131mph. Also went 162 mph (1/4 mile, asphalt) back in 09, with bigger turbo and cams.
Last edited:
Similar threads
