Dyno Tested HKS 280's W/graph
Here's something that may prove to be useful...
I noted (via dyno) an *improvement* in spool time with the 272s at a -3/-3 setting as opposed to a -4/-1 setting, but the peak power was just slightly less.
This tells us that the improvement in spool time was provided by the slight difference in intake valve timing and/or the difference in cylinder pressure provided by an increase in overlap.
In your case, the largely increased overlap seemed to be a detriment. This seems to tell us that the 280s (as set straight up) may provide more effective overlap than we can use where spool characteristics are concerned. Furthermore, as my results for the -3/-3 setting for the 272s indicated, it may also tell us that the increased overlap is not benefitting us on the top end.
As I suggested, I'd like to see -4/-1, or maybe even -3/0, since the longer duration of the 280 set will delay the closing of the intake valve with respect to the 272s.
I noted (via dyno) an *improvement* in spool time with the 272s at a -3/-3 setting as opposed to a -4/-1 setting, but the peak power was just slightly less.
This tells us that the improvement in spool time was provided by the slight difference in intake valve timing and/or the difference in cylinder pressure provided by an increase in overlap.
In your case, the largely increased overlap seemed to be a detriment. This seems to tell us that the 280s (as set straight up) may provide more effective overlap than we can use where spool characteristics are concerned. Furthermore, as my results for the -3/-3 setting for the 272s indicated, it may also tell us that the increased overlap is not benefitting us on the top end.
As I suggested, I'd like to see -4/-1, or maybe even -3/0, since the longer duration of the 280 set will delay the closing of the intake valve with respect to the 272s.
Hey BadazzCR
Were you using the AEM with the GM boost solenoid to control boost on the pump gas runs or did you just switch out from using another boost controler when you moved to the race gas tuning?
Also, have you switched back to the 264's to do race gas tuneing like you were talking about in your other thread?
Thanks,
Keith
Were you using the AEM with the GM boost solenoid to control boost on the pump gas runs or did you just switch out from using another boost controler when you moved to the race gas tuning?
Also, have you switched back to the 264's to do race gas tuneing like you were talking about in your other thread?
Thanks,
Keith
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Originally Posted by Fourdoor
Hey BadazzCR
Were you using the AEM with the GM boost solenoid to control boost on the pump gas runs or did you just switch out from using another boost controler when you moved to the race gas tuning?
Also, have you switched back to the 264's to do race gas tuneing like you were talking about in your other thread?
Thanks,
Keith
Were you using the AEM with the GM boost solenoid to control boost on the pump gas runs or did you just switch out from using another boost controler when you moved to the race gas tuning?
Also, have you switched back to the 264's to do race gas tuneing like you were talking about in your other thread?
Thanks,
Keith
Originally Posted by Ted B
Here's something that may prove to be useful...
I noted (via dyno) an *improvement* in spool time with the 272s at a -3/-3 setting as opposed to a -4/-1 setting, but the peak power was just slightly less.
This tells us that the improvement in spool time was provided by the slight difference in intake valve timing and/or the difference in cylinder pressure provided by an increase in overlap.
In your case, the largely increased overlap seemed to be a detriment. This seems to tell us that the 280s (as set straight up) may provide more effective overlap than we can use where spool characteristics are concerned. Furthermore, as my results for the -3/-3 setting for the 272s indicated, it may also tell us that the increased overlap is not benefitting us on the top end.
As I suggested, I'd like to see -4/-1, or maybe even -3/0, since the longer duration of the 280 set will delay the closing of the intake valve with respect to the 272s.
I noted (via dyno) an *improvement* in spool time with the 272s at a -3/-3 setting as opposed to a -4/-1 setting, but the peak power was just slightly less.
This tells us that the improvement in spool time was provided by the slight difference in intake valve timing and/or the difference in cylinder pressure provided by an increase in overlap.
In your case, the largely increased overlap seemed to be a detriment. This seems to tell us that the 280s (as set straight up) may provide more effective overlap than we can use where spool characteristics are concerned. Furthermore, as my results for the -3/-3 setting for the 272s indicated, it may also tell us that the increased overlap is not benefitting us on the top end.
As I suggested, I'd like to see -4/-1, or maybe even -3/0, since the longer duration of the 280 set will delay the closing of the intake valve with respect to the 272s.
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Ok I have the car on the dyno as I am typing this and wanted to post the first results of the cam timing tests I plan on doing.
Test #1 Set the cam timing to -4 -1.
Run#2 cams set at -4-1
Run#21 cams set at 0
Spool up was actually slower with this setting but it made a few more hp on topend.
Stay tuned I will be posting up graphs from the different settings as I get them.
Test #1 Set the cam timing to -4 -1.
Run#2 cams set at -4-1
Run#21 cams set at 0
Spool up was actually slower with this setting but it made a few more hp on topend.
Stay tuned I will be posting up graphs from the different settings as I get them.
Originally Posted by propellerhead
I seriously love the unbiased testing you're doing.
Can you say "overlap"? I'm guessing the increased overlap is what is killing spool and the ability to keep the boost up. The intake charge is basically flowing right through the intake valves and right out the exhaust valves. I'm not sure I'd use these for a big turbo unless I was looking for an economical drop in installation that doesn't require new springs and retainers that a higher lift cam such as Revolver cams or Piper cams do. The increased overlap is going to hurt spool for a big turbo. Perhaps some cam gears could dial things back in to shape.
My feeling is that HKS brought these to the market to cater to the "if it's bigger it must be better" crowd of bolt on enthusiasts. At least that's my bench racer take on them...
Can you say "overlap"? I'm guessing the increased overlap is what is killing spool and the ability to keep the boost up. The intake charge is basically flowing right through the intake valves and right out the exhaust valves. I'm not sure I'd use these for a big turbo unless I was looking for an economical drop in installation that doesn't require new springs and retainers that a higher lift cam such as Revolver cams or Piper cams do. The increased overlap is going to hurt spool for a big turbo. Perhaps some cam gears could dial things back in to shape.
My feeling is that HKS brought these to the market to cater to the "if it's bigger it must be better" crowd of bolt on enthusiasts. At least that's my bench racer take on them...
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I think I found a winner... set the cams this run at -2 -2 and wow did it pick up some power. Spooled quicker than the -4-1 setting but not yet as quick as the 0 setting.
Oh and yeah this is more power than the car made last night... new record for stock turbo.
Run#2 cams -4 -2
Run#3 cams -2 -2
Run#21 cams 0 0
Oh and yeah this is more power than the car made last night...
new record for stock turbo.Run#2 cams -4 -2
Run#3 cams -2 -2
Run#21 cams 0 0
Originally Posted by BadazzCR
Stay tuned I will be posting up graphs from the different settings as I get them.
What you could do is go from -4/-1 to something like -2/+1. That could be interesting.
At any rate, the duration is so fat at this point that we may be limited as to what we could see by moving in any direction.
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WOW 
just set the cams to +1/-2 just to see and the spool came up really quick and made a ton of torque but lost a bunch on topend.
Run#3 cams -2/-2
Run#5 cams +2/-2
just set the cams to +1/-2 just to see and the spool came up really quick and made a ton of torque but lost a bunch on topend.Run#3 cams -2/-2
Run#5 cams +2/-2
Last edited by BadazzCR; Feb 24, 2005 at 03:40 PM.