how to lower boost to possibly 0-3 psi?
03-18-2008, 08:48 PM
#11
0.5 BAR
Join Date: Jun 2005
Posts: 115
Re: how to lower boost to possibly 0-3 psi?
Originally Posted by jnart
So i guess my next question is if a wastegate is rated at 6 psi, does that mean whenever the gauge reads 6 psi boost it'll open regardless of what the atmospheric pressure is, or when the absolute pressure is 14.7 + 6 = 20.6 psi?
I believe it will because it works a lot like a gauge (diaphragm which will net 0psi at any given altitude), but the turbo may have to work harder to build 6psig!?!?
03-18-2008, 09:09 PM
#12
0.0 BAR
Join Date: Sep 2003
Posts: 0
Re: how to lower boost to possibly 0-3 psi?
Wastegates open based on gauge pressure.
You are going to have to do a lot of work to get what you want. It is not a simple issue. You are going to have to do things in stages in my opinion. Basically buy the smallest WG spring you can possibly get. That will be the low boost. Then buy an EBC. Have a sensor hooked up so that if the pressure outside is around 11.7psi it will use the turbo. Otherwise it will bypass. Then use the EBC and the PA sensor to work in a 1:1 ratio. I'm having trouble thinking of a way to get the turbo to run below the WG spring. I had an idea floating around in my head of pressurizing the spring so that you'd make up the difference of air(if pressure outside is 13.7psi you apply an extra 1 psi to the WG to make it as if it is 1 atm outside) but I don't think it will work well.
Again, a complicated issue. I have thoughts floating around my head, but it seems pretty cloudy which typically means it wouldn't work. Contact http://www.synapseengineering.com/ That guy knows a lot about WG's. I think he will have a solution for you. Also contact the people at Tial. Either company may offer you a solution that I'm not aware of.
You are going to have to do a lot of work to get what you want. It is not a simple issue. You are going to have to do things in stages in my opinion. Basically buy the smallest WG spring you can possibly get. That will be the low boost. Then buy an EBC. Have a sensor hooked up so that if the pressure outside is around 11.7psi it will use the turbo. Otherwise it will bypass. Then use the EBC and the PA sensor to work in a 1:1 ratio. I'm having trouble thinking of a way to get the turbo to run below the WG spring. I had an idea floating around in my head of pressurizing the spring so that you'd make up the difference of air(if pressure outside is 13.7psi you apply an extra 1 psi to the WG to make it as if it is 1 atm outside) but I don't think it will work well.
Again, a complicated issue. I have thoughts floating around my head, but it seems pretty cloudy which typically means it wouldn't work. Contact http://www.synapseengineering.com/ That guy knows a lot about WG's. I think he will have a solution for you. Also contact the people at Tial. Either company may offer you a solution that I'm not aware of.
03-18-2008, 10:27 PM
#13
1.0 BAR
Join Date: Oct 2006
Posts: 536
Re: how to lower boost to possibly 0-3 psi?
Originally Posted by jnart
Hi everyone. i've been assigned to work on a non-typical turbo project for a Plug-in Hybrid Electric Vehicle group at my university. To sum up the purpose, when the car is at high altitude and the atm pressure is lowered to possibly 0.6 atm, the turbo will increase pressure back to sea level conditions at 1 atm. At sea level tho, they just want to maintain 1 atm conditions and so they plan to use an alternator to capture the thermal energy of the turbo to electrical energy to store in the large batteries. Ideally, the alternator will be enough to keep the pressure at 1 atm. But, in case it can't, they don't want the boost to rise and damage the engine.
So, i'm wondering how i can limit the intake pressure to a max of about 1.2 atm, which i think is about 3 psi of boost(ususally people want to raise not lower boost). I've read that u can lengthen the wastegate rod(?not sure how exactly) to lower boost but i'm not sure how much adjustment is possilble.
Please give me any solutions u can. Also, please give as many details as u can like how to connect stuff,what parts do i need,etc, cuz I know the basic theory about turbos, but not really good at exactly how everything fits and where to get parts for cheap.
Thx in advance for any help
PS. the engine is a 1.5L Prius engine and the turbo is a Garrett GT1241(not sure wat rating the wastegate is tho) (http://www.turbobygarrett.com/turbob...1-756068_1.pdf)
So, i'm wondering how i can limit the intake pressure to a max of about 1.2 atm, which i think is about 3 psi of boost(ususally people want to raise not lower boost). I've read that u can lengthen the wastegate rod(?not sure how exactly) to lower boost but i'm not sure how much adjustment is possilble.
Please give me any solutions u can. Also, please give as many details as u can like how to connect stuff,what parts do i need,etc, cuz I know the basic theory about turbos, but not really good at exactly how everything fits and where to get parts for cheap.
Thx in advance for any help
PS. the engine is a 1.5L Prius engine and the turbo is a Garrett GT1241(not sure wat rating the wastegate is tho) (http://www.turbobygarrett.com/turbob...1-756068_1.pdf)
then you could switch it off at sea level also
or if you are having such a hard time just get a really big turbo and run a 6spi wg spring (for insurance) because the 1.5 will never spin a large turbo to more than 4-5psi even at 6-7krpm because it just dosen't push enough air
but that is just me
03-19-2008, 01:17 AM
#14
!! UNCONFIRMED EMAIL !!
Join Date: Sep 2007
Posts: 1,305
Re: how to lower boost to possibly 0-3 psi?
Originally Posted by cornfuzed
if you want such low boost why not just use one of those ebay electric turbos (i think they are rated at like 2-3psi, and are only like $20)
then you could switch it off at sea level also
or if you are having such a hard time just get a really big turbo and run a 6spi wg spring (for insurance) because the 1.5 will never spin a large turbo to more than 4-5psi even at 6-7krpm because it just dosen't push enough air
but that is just me
then you could switch it off at sea level also
or if you are having such a hard time just get a really big turbo and run a 6spi wg spring (for insurance) because the 1.5 will never spin a large turbo to more than 4-5psi even at 6-7krpm because it just dosen't push enough air
but that is just me
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