HKS SC + 85mm Pulley = Out of Breath?
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HKS SC + 85mm Pulley = Out of Breath?
I've done some reading about Z guys pushing 10psi on their HKS SC kit by using 85mm pulley. After ordering an waited anxiously for it to arrive, guess what? As the title says, it went off the efficiency range. Not only I'm not getting higher boost, its dropping off after 5500rpm. The boost gauge reads 0.5bar of boost at 5500rpm. After that, it just falls all the way down. At 6500rpm, I'm only at less than 0.3 bar.
Anyone who knows what exactly went wrong please advise. It felt so crappy now. I'd rather just go back to stock pulley compared to what I'm having now.
Anyone who knows what exactly went wrong please advise. It felt so crappy now. I'd rather just go back to stock pulley compared to what I'm having now.
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I've checked all the joint so I'm sure its not air leak. My guess is the SC ran out of efficiency range. But how did the other HKS SC guys get 10psi from their system? Mine is already dipping far from there.
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hmm, I am seeing 12 psi peaking at 4500, but it does start to dip after 6000 rpms. I can tell you that with the HKS SC, you cannot just put on a smalley pulley and get significant increase in boost. There is much more too it than that, but it is achievable, as my setup shows. My suggestion is to contact SAM@GTM (who customized my kit), he is most knowledgeable about maximixing power with the HKS SC kit.
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hmm, I am seeing 12 psi peaking at 4500, but it does start to dip after 6000 rpms. I can tell you that with the HKS SC, you cannot just put on a smalley pulley and get significant increase in boost. There is much more too it than that, but it is achievable, as my setup shows. My suggestion is to contact SAM@GTM (who customized my kit), he is most knowledgeable about maximixing power with the HKS SC kit.
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My setup is around there. Just didnt have the ATI pulley. Do you know if Sam@GTM could be generous enough to give me some pointers and advise? Thanks.
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I got 7PK1030 belts and they are tight. I understand there are certain things being done by GTM to achieve such boost. Mind helping me out? I would love to send my car to them but due to the distance, its impossible.
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physical appearance should look rather identical. Just written to Sam@GTM. Hope he have a solution for my problem.
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No one knows? Anyway, I will be sending the compressor housing to a machine shop to try out different things. Not too sure if it works but its worth a try. I'll post my results later.
#20
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On the original HKS SC kit the smallest pulley size you could use in theory was about 89mm from the OEM 95mm based on a 142.6 crank pulley size and 6600 rpm cut. This kept the pulley rpm at 10453 rpm and the impeller at 99131 rpm which were just under the warranty limits.
Formula as supplied by rotrex:
I = E x ((Dc+2.8)/(Dp+2.8)) x 9.483
I = Impeller speed max
E = Engine Speed max
Dc = Crank Pulley Diameter
Dp = S/C Pulley Diameter
Pulley(mm), Impeller RPM, Pulley RPM
95 93049.76 9812.27
94 94011.01 9913.64
93 94992.34 10017.12
92 95994.37 10122.78
91 97017.76 10230.70
90 99166.89 10457.33
89 99131.44 10453.59
88 100223.20 10568.72
Michael
Formula as supplied by rotrex:
I = E x ((Dc+2.8)/(Dp+2.8)) x 9.483
I = Impeller speed max
E = Engine Speed max
Dc = Crank Pulley Diameter
Dp = S/C Pulley Diameter
Pulley(mm), Impeller RPM, Pulley RPM
95 93049.76 9812.27
94 94011.01 9913.64
93 94992.34 10017.12
92 95994.37 10122.78
91 97017.76 10230.70
90 99166.89 10457.33
89 99131.44 10453.59
88 100223.20 10568.72
Michael
Last edited by MR RIZK; 10-08-2009 at 06:41 AM.