Drive Pressure with s400

GOT-Torque said:
So you tried bigger exhaust housings and it didn't change much?
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It changed the rpm where it lights but no much. Overall boost and drive pressure did not change. I have run 1.01, 1.15, and 1.28 housings. I feel that I am simply at the flow of the turbine wheel. Going from 1.01 to the 1.15 made the biggest difference. I could not really tell any difference between the 1.15 and the 1.28. On nice thing about Garrett is they publish the flow charts of their turbines. If you look at the graph you can see that over all flow does not really cahnge much from the 1.15 housing on up.
731376-2turb_e.jpg


In my talks with Forced Inductions they said that the 83mm S400 flows really close to the GT42 turbine. Actually a hair less, and that the 87mm flows a good deal more. This a flow chart of the the 87mm Garrett GT45 87mm turbine.
GT4508R_Turb_large.gif


Flow does not increase a whole lot either. That has me scratching my head. I figured it might be because the GT42 and GT45 T4 housings are the same just machined differently for the different size turbine. I wonder if the same turbine wheel would flow better a T6 housing? How the GT45 87mm turbine compares flow wise to the 87mm S400 turbine is another good one question?

The more I think about the more I like the idea of athe smaller turbine with a gate setup to reference off drive pressure. That way I can easily spool it and make all the boost I want as long as I can do it efficiently.
 
what kind of drive pressureshould i expect ot see with a 475 t4 foot .9ar 83 turbine wheel?
 
SMOKIN-U said:
what kind of drive pressureshould i expect ot see with a 475 t4 foot .9ar 83 turbine wheel?
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Should be around 1:1, upwards of 10psi over boost. It will depend on rpm and amount of fuel past the usable point of injecting fuel. I think p-pumps make a ton more dp cause they inject alot more fuel thats unburnt in the cylinder, some of that burns in the ex making for higher dp's. CR's burn most of thiers in the cylinder wich spools the charger quicker but also keeps dp's lower.
 
I would like to know some of the RPM people are seeing the high drive pressues at. If I would follow a CR rpm curve, I would be close to the 10 psi over boost, but hitting some rpm down the track pushes the DP up, and the boost stays pretty constant.
 
Dan the higher the rpm, the motor is using more air. So you boost going to level off and drive continues to climb. Your turbine becomes the restiction.
 
GRotman said:
Dan the higher the rpm, the motor is using more air. So you boost going to level off and drive continues to climb. Your turbine becomes the restiction.
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Yeah with my 66 when I would floor it in 3rd gear boost would be 40lbs and drive would shoot up to 60lbs, but when I let it hit overdrive the drive would level back down to 40-45lbs with the drop of RPM's
 
GRotman said:
Dan the higher the rpm, the motor is using more air. So you boost going to level off and drive continues to climb. Your turbine becomes the restiction.
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Yes I agree, just trying to clarify that with some folks.
 
zstroken said:
I would like to know some of the RPM people are seeing the high drive pressues at. If I would follow a CR rpm curve, I would be close to the 10 psi over boost, but hitting some rpm down the track pushes the DP up, and the boost stays pretty constant.
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Dan, I can solve your problem, just set the govenor to limit it to say around 3600 rpm, wa la, drive pressure issues fixed!!!!!!!!!!!!!
 
Gwoody said:
Dan, I can solve your problem, just set the govenor to limit it to say around 3600 rpm, wa la, drive pressure issues fixed!!!!!!!!!!!!!
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Thanks Garry, always looking out for me! I will do that if you promise to keep the truck in second gear while your pulling.
 
BTW something new and very shiny showed up at the house yesterday. Now if I could just get all the pieces to put it together, it would make for a very interesting show at Neosho!
 
At this point I would be happy if it would pull itself down the road in 2nd gear!!!


On the shiny thingy, you got plenty of time, get it!!!!
 
DISTURBED said:
Dan, mine turns 5k+ and stays a constent 10psi difference all the way through the rpm range with no WG.
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Nice thing about not running an auto....you can actually run a decent size turbine wheel.
 
zstroken said:
I am waiting on a housing. We will see what happens.
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What if you went with a bigger wheel and no WG? Should let it breath better, but with the auto would it breath to much and not let it light?

Sorry slow computer today grotman just saw your post
 
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