HKS 264's VS GSC S2's For DSM

olmytsi · 02-25-2011, 09:20 AM

Have they redesigned the S1's as well? That's what I've been running since August 2009 and I love them!!!!!!!!!!!

brian9397gsx · 02-25-2011, 09:25 AM

Any word on that group buy I really want a set of s2's

D's GS-T · 02-25-2011, 12:43 PM

So for a 2.3l and something like an HTA30R Or FP Green im looking at the GS2 cam it sounds like? Not to get off topic, but how do you guys like the HTA Green. Seems like people are afraid of it in one of the turbo system threads since it isn't using some mitsu parts or some shit. Im thinking my 2.3 with the HTA Green and the GS2 Would be awsome.

Nate Crisman · 03-17-2011, 05:52 PM

Bringing this back from the dead, but I was wondering if there was any input on the previous version of the S2 cams. I picked up a parts car that has these cams, but they were bought in summer 2010, so not this current re-design. Wondering if I would be better off using them rather than the HKS 264I/272E cams?

Lucas's opinion is most solicited, as he's the man with automatic/16G experience.

brian9397gsx · 03-17-2011, 07:04 PM

I purchased a set of s2 s and installed them last weekend car has not be run. My main concern is on #4 cylinder the lobes of the cam (both Intake and exhaust) are vary close to the cam cap is this normal? It seems that 1 and 2 are good but 3 and 4 get progressively closer (does not touch) if its normal Im willing to leave it at that.

VETTE_50_TH · 03-17-2011, 11:44 PM

Yes. Its normal.

Nate Crisman · 03-18-2011, 05:21 AM

Anyone have the cam card specs for the previous version S2 cams to compare against the this current re-design?

cherrod8 · 03-18-2011, 06:13 PM

Quote:

Originally Posted by Nate Crisman

Anyone have the cam card specs for the previous version S2 cams to compare against the this current re-design?

i would like to know also

VETDRMS · 03-18-2011, 09:25 PM

Quote:

Originally Posted by brian9397gsx

I purchased a set of s2 s and installed them last weekend car has not be run. My main concern is on #4 cylinder the lobes of the cam (both Intake and exhaust) are vary close to the cam cap is this normal? It seems that 1 and 2 are good but 3 and 4 get progressively closer (does not touch) if its normal Im willing to leave it at that.

Mine were the exact same way. The #4 intake rocker's roller is actually not even on the cam lobe on the edge...

brian9397gsx · 03-19-2011, 08:53 AM

The cam lobe is not centered on mine but all of the roller is on the lobe on mine. If its normal its normal I'm not gonna complain especially with the performance I should see from them.

e85_4g63 · 03-19-2011, 03:21 PM

I'd def want to see what changed (and more importantly, WHY did it change) over the 1st gen. of the S2 cams.

ViciousLord · 03-19-2011, 05:12 PM

Quote:

Originally Posted by e85_4g63

I'd def want to see what changed (and more importantly, WHY did it change) over the 1st gen. of the S2 cams.

They redesigned the S2 cam after AMS did cam testings (EvoM) on a whole bunch of different cams. The Version 1 S2 cams that AMS tested made great power but lacked mid-range, this may be the reason why they redesigned it.

Nate Crisman · 03-19-2011, 06:20 PM

Quote:

Originally Posted by ViciousLord

They redesigned the S2 cam after AMS did cam testings (EvoM) on a whole bunch of different cams. The Version 1 S2 cams that AMS tested made great power but lacked mid-range, this may be the reason why they redesigned it.

That's exactly what I was afraid off, and why I have to find out more info before deciding to use the GSC S2 cams that I have. I suspect they are the older version as they were bought in summer 2010 and Lucas posted this thread as "first to test the new design" in 2011.

Given the info in this thread from Lucas, it seems the new design S2 cams still give up significant torque from 4000rpm to 5000rpm, which just so happens to be the launch rpm for my automatic/stock converter car to leave and pull through the 60'. There are spots where tq is down 70-80ftlb! Granted, Lucas tested with a 3065 turbo and saw a 400rpm spool difference which accounts for the large majority of the torque deficit. But even from 4500-5000rpm, the S2 cams are still down compared to the hks 264's once both are at the same 20psi of boost.

It's hard to judge how the spool loss will affect an e3 16g compared to the 3065, as my launch rpm of 4200 should still be way above the "full spool" rpm. The loss in spool-up due to the bigger cams might not effect the launch and 30+psi might still be attainable on the converter since the E3 16g comes up to 20+psi about 3500rpm.

On the other hand, if the previous version of the S2 cams are even worse than the current S2 grind for midrange torque, as you eluded to the reason for the re-design, then that's really bad news for an automatic car.

The current grind might be a wash where gaining 750rpm of top end breath is negated by the loss in first gear. The previous gring might be a net loss.

ViciousLord · 03-19-2011, 08:15 PM

I'm sure you got the revised version... I was thinkin' about switching to the revised S2s in my Evo, late 2008.

And the AMS testing was done late 2007/ early 2008, I heard rumors of the redesign before the AMS results were ever posted.

your best bet is to contact Greg at GSC, only he can confirm the dates.

mat305 · 03-20-2011, 09:59 AM

Very nice!

thilaksharma · 10-28-2011, 12:15 AM

bringing this topic back to live

do u guys think for a 2.2L destroke + HX35 .70 turbine housing will suit a S1 or S2 , bare in mind its a track time attack car n not a drag car

VETDRMS · 11-18-2011, 01:07 PM

Quote:

Originally Posted by thilaksharma

bringing this topic back to live

do u guys think for a 2.2L destroke + HX35 .70 turbine housing will suit a S1 or S2 , bare in mind its a track time attack car n not a drag car

I think with the additional displacement the S2 would still be a good fit. I just made 444 awhp through an auto at 25psi. HP is pretty flat from 6000-7500rpm. I can't really create any low rpm loads due to the converter though. It really doesn't feel "peaky" but I haven't tried anything else for comparison.

NDgsx · 12-03-2011, 12:13 PM

Just noticed some comments in this thread. The DSM S2 is a completely new design and was never revised at any point. They were only ever released with the then garnered knowledge from Evo 8s and engine simulation prior to release.

In an Evo 8 there is no appreciable spool loss on small turbos. I havent seen any issues until we get to an S3 on a 2.0L or smaller than 2.1 and then its the same as what we saw here with the HKS264s vs S2s. Since the 264s are only slightly better than stock cams in my opinion a 400 rpm loss from stock to a real profile isnt that big of a deal.

Also remember a dyno with the load control off is no comparison to the street or load with a boost braked auto.

Aaron

NDgsx · 12-03-2011, 12:14 PM

Sharma,

I would run the S2 with that combo and the 2.2L displacement. A 92mm crank or 94mm or the even rarer turned down diesel crank?

Aaron

LuizHGato · 01-21-2012, 05:20 AM

That you would like me to clarify an intuition:
I've seen graphs of flow bench, I realize that this HKS 272 at the edge of the valve lift and cfm peak.
This suggests to me that cams with more lift than the peak cfm would cause losses on stock head?
For example using kelford 272 in the head stock, it would be worse than using HKS 272. Even kelford a command that comes with more gains .. correct?

VETDRMS · 01-21-2012, 07:55 AM

Quote:

Originally Posted by LuizHGato

That you would like me to clarify an intuition:
I've seen graphs of flow bench, I realize that this HKS 272 at the edge of the valve lift and cfm peak.
This suggests to me that cams with more lift than the peak cfm would cause losses on stock head?
For example using kelford 272 in the head stock, it would be worse than using HKS 272. Even kelford a command that comes with more gains .. correct?

Even if you open the valve past the peak "lift-cfm" you still get the benefit of a faster opening ramp rate, meaning the delta between seat-open and open at peak cfm is smaller. Therefore you get more time at, or near, peak cfm. Which typically means more power.

NDgsx · 02-01-2012, 10:19 AM

So we just did a test on the HKS 272 (full set, not 264/272 in this test) and had very surprising results. I am Johnbradley on that forum-

Old test done again HKS 272 VS GSC S2 30hp gain - evolutionm.net

I will also move those results over here for discussion. Max lift vs max flow is easy really. Normally our heads plateau at 10.8-11mm lift. More lift doesnt mean less air, it just doesnt mean more air. So for a given duration more air is still going on in if the lift is higher. This allows the engine to run a slightly smaller cam without having idle issues.