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Old 12-31-2007, 01:42 AM   #1
02RSBRP
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Post Delta Cam Comparison (updated 3/06)

Ok so I finally got all the profiles for the following 2.5l SOHC: Stock, Delta 148 grind, Delta 2000 grind, stock vs 148, stock vs 2000, 148 vs 2000, and then one comparing them. I put all the profiles into excel and did some graphs up of them. Below is the graphs that you can take a look at. I would like to get the profile data for the other Cams that are available to us so I can compare those also. The lift on the side is actually the valve lift. The RAR is the Rocker Arm Ratio wich is multiplied times the actual cam lift.

I added the actaul cam profiles, not the actaul valve lift for those that would rather see those. On the new graphs don't worry about the lines at the bottom of the graph, just something I was working on for valve lash.

Valve lift

Stock



148


st vs 148


2000


st vs 2000


148 vs 2000


all



Cam Lift

stock


148


2000
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Last edited by 02RSBRP; 11-24-2008 at 05:00 PM. Reason: Up dated link to graphs.
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Old 12-31-2007, 06:40 PM   #2
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Default More information while comparing

Here is some information that you may want to consider when comparing the cams.

VARYING LOBE SEPARATION ANGLE
...............Tighten ………………..........…..……………. Widen
Moves Torque to Lower RPM…………...... Raise Torque to Higher RPM
Increases Maximum Torque ……….......… Reduces Maximum Torque
Narrow Power band ……….. ……………...... Broadens Power Band
Builds Higher Cylinder Pressure …………... Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock …..…… Decrease Chance of Engine Knock
Increase Cranking Compression ……....…. Decrease Cranking Compression
Increase Effective Compression ………..... Decrease Effective Compression
Idle Vacuum is Reduced …………………...... Idle Vacuum is Increased
Idle Quality Suffers ………………………........ Idle Quality Improves
Open Valve-Overlap Increases …….…...... Open Valve-Overlap Decreases
Closed Valve-Overlap Increases …….....… Closed Valve-Overlap Decreases
Natural EGR Effect …………………….......….… Increases Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance …… Increases Piston-to-Valve Clearance

LOBE SEPARATION ANGLE
Above 114 Deg. = Extremely Wide
114-112 Deg. = Wide
112-110 Deg. = Moderately Wide
110-108 Deg. = Moderate
108-106 Deg. = Moderately Tight
106-104 Deg. = Tight
Below 104 Deg. = Extremely Tight

ADVANCING / RETARDING CAM TIMING
.............ADVANCING …………......………........……… RETARDING
Begins Intake Event Sooner ……….......……. Delays Intake Event Closes Intake
Open Intake Valve Sooner ……………......…… Keeps Intake Valve Open Later
Builds More Low-End Torque ……….......……. Builds More High-End Power
Decrease Piston-Intake Valve Clearance …. Increase Piston-Intake Valve Clearance.
Increase Piston-Exhaust Valve Clearance … Decrease Piston-Exhaust Valve Clearance
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Old 12-31-2007, 06:52 PM   #3
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This is some good info. This should be stickied.
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Old 01-01-2008, 12:44 PM   #4
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Where did you get the profile data from? Did you degree the cams yourself?
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Old 01-01-2008, 04:35 PM   #5
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I got all the data from Delta Cams. They sent me the data sheets for the different cams.
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Old 01-01-2008, 10:40 PM   #6
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I'll be damned. I've seen duration and lift numbers for other cams before, but never the real profiles like that.
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Old 01-02-2008, 12:05 AM   #7
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OK, so help a cam noob like me figure this out. I'm working off of your little list up there so check to see if I understand this.

Compared to stock, the 148 grind has greater separation between lobes, more lift, more duration, but less overlap. This means the 148 grind will have peak torque at lower RPM, but peak torque will be higher and the cam will require less timing.

Compared to stock, the 2k grind has less separation between lobes, very slightly more lift, much more duration, and more overlap. This means peak torque will be at a higher RPM, and the peak torque will be lower, however, it will allow more timing to be run.

Is that a correct interpretation? If so, what's the point of the 2k grind?
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Old 01-02-2008, 02:14 AM   #8
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Quote:
but peak torque will be higher and the cam will require less timing
Quote:
and the peak torque will be lower, however, it will allow more timing to be run
Basically the 148 grind gives you more low and mid power, but won't give you anything up top. The 2000 grind gives you more mid and upper power. So for people looking for more top end power, they would get the 2000 grind. If you look at the graphs, the new profiles of the cams have altered the timing already.

Quote:
I'll be damned. I've seen duration and lift numbers for other cams before, but never the real profiles like that
I'm more of a visual person when it comes to comparing two things. Plus with the graphs I can see where the difference are. I just basically took the profile sheets I got from Delta and put it into Excel then graphed them. It definetly made it alot easier to see the entire profile of each cam.

Last edited by 02RSBRP; 01-02-2008 at 03:44 AM.
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Old 01-02-2008, 08:46 PM   #9
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Thank you so much! You rock
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Old 01-02-2008, 11:27 PM   #10
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I'm just trying to learn more about these engines and what is available. Figured what I come across should be shared.

Last edited by 02RSBRP; 02-29-2008 at 03:16 AM.
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Old 02-28-2008, 06:56 PM   #11
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See next post.

Last edited by 02RSBRP; 02-29-2008 at 03:17 AM.
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Old 02-29-2008, 03:18 AM   #12
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Alright guys. Those are all the graphs for your viewing pleasure. I hope this helps people out.
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Old 02-29-2008, 04:38 AM   #13
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Great stuff. thanks for the hard work
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Old 02-29-2008, 07:35 AM   #14
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I'm with you on being visual, I happy I got some 2000 grind from ^^^^^^
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Old 02-29-2008, 04:34 PM   #15
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Quote:
Originally Posted by 02RSBRP View Post
Basically the 148 grind gives you more low and mid power, but won't give you anything up top. The 2000 grind gives you more mid and upper power. So for people looking for more top end power, they would get the 2000 grind. If you look at the graphs, the new profiles of the cams have altered the timing already.
Going to ask a silly question here...

For our cars, what are the rev ranges for low, mid, and high?
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Old 02-29-2008, 06:51 PM   #16
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Well our Rev limit is 6200 RPM's. So Low would be less than 3k, mid would be 3k to 5k, and high end is greater than 5k. Not sure if this is what everybody else looks at, but that's how I seperate them out.
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Old 03-01-2008, 02:43 AM   #17
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Anyone know if delta has made cams for the 2.5i. I heard they were like 6 months ago. And what kind of power gains would you guys think it would give.

Thanks!
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Old 03-01-2008, 12:22 PM   #18
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Delta doesn't make cams. You have to remove your stock cams and send them to Delta. They regrind the cams to the new profiles and you reinstall. The 2.5i has the same EJ25 as all the older ones, so it they should be able to regrind them no problem.
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Old 03-01-2008, 07:30 PM   #19
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Not quite. The EJ253 in the 2.5i has i-AVLS, which means there are three intakes lobes per cylinder. One valve operates on the low lift lobe until conditions are met for the rockers to lock together and have the valve use the high lift lobe.
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Old 03-01-2008, 08:21 PM   #20
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Ok I must have missed that. I looked it up to see if the 2.5i had AVLS, but didn't see anywhere that said it did. I know the DOHC models do, but didn't think the SOHC did. Thanks for the info Counterfit.
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Old 03-03-2008, 02:48 AM   #21
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ok thanks guys. i was told something different a long time ago..so glad you guys cleared that up. and yes the 2.5i has i-AVLS thats why i was asking cuz i still dont know if they can do it to my car without messing up the i-AVLS. anyone know what kinda of hp gains would come from these guys messing with the cams??

thanks guys!
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Old 03-03-2008, 09:06 PM   #22
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I would call Delta and talk to them about it. I'm sure that they could probably do a grind on the i-AVLS cams. Probaly run a little bit more since they have to grind two extra lobes on the intake valves. They may still be working on what kind of profile or something.
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Old 03-04-2008, 01:12 AM   #23
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What has the average mailbox to mailbox timeframe been for people?
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Old 03-04-2008, 02:22 AM   #24
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i'm going to call up delta once i get some money and see what they can do for me

anyone know who the hell i could get to remove my cams?

i can't do that stuff myself ><
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Old 03-04-2008, 01:59 PM   #25
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Quote:
Originally Posted by HeyChris View Post
What has the average mailbox to mailbox timeframe been for people?
From what I've seen over on RS25, they will do the grind the same day they receive them, send them out the next day. So theoretically, you could have everything done in a week from the time they leave, to getting them in the car.
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