440dart123
Well-Known Member
Just wondering if anybody has an idea of what kind of rpms my 360 will turn running two hx35s one guy thinks they will start chokeing it off around 5k iam sure hopeing i can get 6500+.
twin turbo 360 rpm limit?
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440dart123
Well-Known Member
Sorry most of the people in the forced induction section already know my build.
360 stock 72 specs
308 casting 2.02 1.60 dual springs
crane blazer cam 300dur and 501 lift
tourqer II 340 intake
Iam not concerned about my build lasting i already know that it wont and it dont matter that it does, My question is will my 360ci engine be able to spin 6500+ with the hx35s and not being choked off if it starts chokeing off around 5k iam probley going to detonation issues and need to change my build a little bit to accomadate the lower rpm range.
No reason to spin over 5500 with a turbo.
First you need a target horsepower number. Then you calculate the mass flow.
Let's say you want 600 horsepower. To get there you will need 57 lbs of air per minute stuffed in to that 360 @ 5500 rpm
VE calcs say about 12.6 psi boost should get you there. That gives a pressure ratio of 1.86
Map for the Hx35:
So divide the mass flow by 2 for twin turbos, and you get 28.5 lbs/min flow. The intersection of 1.86 & 28.5 is no where near the choke line.
Let's say you want to get stupid, and go for 2.5 hp / cid - 900 hp @ 5500 rpm:
86 lbs / min flow /2= 43 lbs/min 27psi boost = 2.83 pressure ratio
Nope, still not choking, and actually still near the 72% line.
Ok, how about 900 horsepower @ 4500 rpm? Still need 86 lbs of air, so the boost goes up to 35psi. Pressure ratio of 3.4
Nope, no choke even there. Still on the map.
But you wanted high rpms. So 900 hp @ 8,000 rpm 14 psi boost. 1.9 pressure ratio. Still 86 lbs/min NOW you are getting close to the choke line.
Bottom line is keep the rpms lower. Spin to 4500 & ask for 500 horsepower. 13 psi of boost & 47 lbs/min flow. It will live a long time.
B.
First you need a target horsepower number. Then you calculate the mass flow.
Let's say you want 600 horsepower. To get there you will need 57 lbs of air per minute stuffed in to that 360 @ 5500 rpm
VE calcs say about 12.6 psi boost should get you there. That gives a pressure ratio of 1.86
Map for the Hx35:
So divide the mass flow by 2 for twin turbos, and you get 28.5 lbs/min flow. The intersection of 1.86 & 28.5 is no where near the choke line.
Let's say you want to get stupid, and go for 2.5 hp / cid - 900 hp @ 5500 rpm:
86 lbs / min flow /2= 43 lbs/min 27psi boost = 2.83 pressure ratio
Nope, still not choking, and actually still near the 72% line.
Ok, how about 900 horsepower @ 4500 rpm? Still need 86 lbs of air, so the boost goes up to 35psi. Pressure ratio of 3.4
Nope, no choke even there. Still on the map.
But you wanted high rpms. So 900 hp @ 8,000 rpm 14 psi boost. 1.9 pressure ratio. Still 86 lbs/min NOW you are getting close to the choke line.
Bottom line is keep the rpms lower. Spin to 4500 & ask for 500 horsepower. 13 psi of boost & 47 lbs/min flow. It will live a long time.
B.
rgreule
Well-Known Member
a guy in town has a s10 with a ls swap and twin hx35s.. he has run 9.90s.. but at rediculas boost like 30+ psi.. he revs to 7 for some reason.. id say the turbine wheels are done at like 5500 max..
rgreule
Well-Known Member
cam duration is WAY to big.. should be around 235 @ .50
440dart123
Well-Known Member
Yeah iam thinking of forking out some money and going with a differnt cam thanks for the info guys
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