Solving the HKS 272 Cam Timing Mystery
Sep 26, 2004, 04:00 PM
#1
Solving the HKS 272 Cam Timing Mystery
I am working in France at the present, while my car goes from bone stock to the following mods, courtesy of Dyno4mance:
Vishnu Stg 1+ HKS 272s (gears, full exhaust, Xede, Xflash, Shiv custom dyno tune)
10.5t Turbo
Helix O2 Housing
AMS Lower IC Pipe
Injector Clinic 650cc
255lph Fuel Pump
EVO MR BOV
A tried and tested HKS 272 setting for similar setups are -2/-2 (int/exh). We've read reports of some who've had this and -3/-3 settings dialing out a bit of overlap to the following -4/-1.5 (int/exh) and claiming stronger midrange torque, and verifiably better 1/4 ETs (0.2 sec or so). Unfortunately, dyno testing multiple cam settings is time consuming, expensive, and tedious for even tuners and dyno shops.
What I am going to do is have Shiv tweak the car with the proven -2/-2 settings, following which I will have Andrew change the settings to -4/-1.5 and dyno the difference. We will pay close attention to the A/F such as to determine any changes therein, and determine its impact (if any) on the result. In any case, I'm hoping the results, for better or worse, will be of benefit in determining more effective cam timing settings for this particular cam set given similarly equipped cars.
Vishnu Stg 1+ HKS 272s (gears, full exhaust, Xede, Xflash, Shiv custom dyno tune)
10.5t Turbo
Helix O2 Housing
AMS Lower IC Pipe
Injector Clinic 650cc
255lph Fuel Pump
EVO MR BOV
A tried and tested HKS 272 setting for similar setups are -2/-2 (int/exh). We've read reports of some who've had this and -3/-3 settings dialing out a bit of overlap to the following -4/-1.5 (int/exh) and claiming stronger midrange torque, and verifiably better 1/4 ETs (0.2 sec or so). Unfortunately, dyno testing multiple cam settings is time consuming, expensive, and tedious for even tuners and dyno shops.
What I am going to do is have Shiv tweak the car with the proven -2/-2 settings, following which I will have Andrew change the settings to -4/-1.5 and dyno the difference. We will pay close attention to the A/F such as to determine any changes therein, and determine its impact (if any) on the result. In any case, I'm hoping the results, for better or worse, will be of benefit in determining more effective cam timing settings for this particular cam set given similarly equipped cars.
Sep 26, 2004, 04:06 PM
#2
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Finally! An apples to apples comparison! I'm anxiously awaiting, Ted. Try advancing the cams as well. That will build early torque, I think. Obviously, once you set the cams 3 degrees apart, the idle will smooth out. IE 113 deg. lobe seperation. Anyway, I could go on and on. Let us know!
-chris
-chris
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Oct 1, 2004, 03:39 PM
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That's very similar to my proposed setup.
Can you ALSO test 272 Intake & 264 Exhaust?
A lot of tuners say that this cam setup is even better, because they say turbo engines need MORE intake duration than exhaust duration.
Case in point - Stock Evo cam duration: 260 In / 256 Ex.
Maybe THAT'S why a -4In / -1.5 Ex timing setup works so well with two 272 cams???
Great post. Looking forward to dyno data. Hope you can test 272 I / 264 E cams as well.
Can you ALSO test 272 Intake & 264 Exhaust?
A lot of tuners say that this cam setup is even better, because they say turbo engines need MORE intake duration than exhaust duration.
Case in point - Stock Evo cam duration: 260 In / 256 Ex.
Maybe THAT'S why a -4In / -1.5 Ex timing setup works so well with two 272 cams???
Great post. Looking forward to dyno data. Hope you can test 272 I / 264 E cams as well.
Oct 1, 2004, 03:59 PM
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Lamb; would you mind posting the graphs on your 272/264 set up. It will be a few days till we get the results from the 272/272 set up and "Same power" is some what nondescript.
Oct 1, 2004, 06:59 PM
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Originally Posted by lambtron@vishnu
haha I was actually just looking for the graph last night but I can't find it, I don't remember which ID I used for myself last time when we dyno'd it 
Oct 2, 2004, 06:01 AM
#15
Yeah let's see some results, or at least why I might want to go with a staggered set up.
I'm getting ready to slap in the 272/264 set up myself (based on the stock set up, a local tuner's advice, and Dustin's recommendations
not in the forum but over the phone.
I got the same story, the tuner told me that "the air has to be coaxed in (at least relative to the exhaust, where-as the exhaust has no choice but to exit, because of pressure and vacume considerations, it got a little technical after that.)
Supposedly I'll be picking up a flow advantage over stock, or a straight 264, or a 264/272 set up, but it will keep the idle and drivabilty of the car a little more civilized than a straight 272, for the street.
Why would I want to do a staggered set up if there isn't really some kind of advantage over a straight 264 set up (or really, even over a 264/272 set up, which as we all know, most guys who "go combo", are using)? (BTW not interested in a straight 272 set up right now),
Enlighten me please,
and Thanks
I'm getting ready to slap in the 272/264 set up myself (based on the stock set up, a local tuner's advice, and Dustin's recommendations
not in the forum but over the phone. I got the same story, the tuner told me that "the air has to be coaxed in (at least relative to the exhaust, where-as the exhaust has no choice but to exit, because of pressure and vacume considerations, it got a little technical after that.)
Supposedly I'll be picking up a flow advantage over stock, or a straight 264, or a 264/272 set up, but it will keep the idle and drivabilty of the car a little more civilized than a straight 272, for the street.
Why would I want to do a staggered set up if there isn't really some kind of advantage over a straight 264 set up (or really, even over a 264/272 set up, which as we all know, most guys who "go combo", are using)? (BTW not interested in a straight 272 set up right now),
Enlighten me please,
and Thanks
Last edited by nirvevo; Oct 2, 2004 at 06:04 AM.