Split duration vs single pattern cams, and a valve spring question
Thread Starter
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
Split duration vs single pattern cams, and a valve spring question I’m pretty well decided on the Comp 216/220 cam for my setup next year (using stock heads/intake) to go with all the other common bolt-ons (including headers). But I’m still trying to learn about split duration vs. single pattern. The only thing I can seem to find so far is that split duration cams seems to idle better, but what are the other major differences? I think for my application this 216/220 cam will be plenty big, but would I be better off with a single pattern?
So what are the pros and cons of single vs split?
Also, what are the differences between the comp 915 and 918 springs? Which one would be better for the 216/220 cam?
Thanks.
So what are the pros and cons of single vs split?
Also, what are the differences between the comp 915 and 918 springs? Which one would be better for the 216/220 cam?
Thanks.
TECH Addict
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From: Nawf Carolina
Re: Split duration vs single pattern cams, and a valve spring question I've heard singles make more power in a heavily modified ported head car with race headers and all the tricks. The LS1 has fairly good flowing exhuast ports from what I understand, so that would make it a quasi-race head. I thought singles idled better than splits.
Since the LS1/LS6 exhaust port flows so well, and the intakes suck, I'd be interested to see what a 6.0+ liter engine would do with more intake duration than exhuast. Like a 228/225 or something.
J.
[ November 30, 2001: Message edited by: Crazyquik ]</p>
Since the LS1/LS6 exhaust port flows so well, and the intakes suck, I'd be interested to see what a 6.0+ liter engine would do with more intake duration than exhuast. Like a 228/225 or something.
J.
[ November 30, 2001: Message edited by: Crazyquik ]</p>
Thread Starter
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From: Schiller Park, ILL Member: #317
Re: Split duration vs single pattern cams, and a valve spring question So if singles make more power and idle better then what is the advantage (or reason) for splits? Our stock cam is split, correct?
Re: Split duration vs single pattern cams, and a valve spring question singles idle better than splits, and they also give your PCM less grief (random misfire SES codes).
Why split patterns? The longer exhaust duration is helpful if you are running a semi-restrictive exhaust setup, as with stock manifolds and catalytics. If you are running headers, and especially an offroad Y-pipe setup, then there is little to gain from that extra exhaust duration. This is especially true on a stock head motor, or anything else less than 400 rwhp in my opinion.
If you are worried about idle quality, go with more lobe seperation instead. Maybe a 221/221 on a 116 LSA. Choose whatever lift you want, it doesn't affect idle. Just know your limitations on piston/valve clearance issues and your valvespring coil bind limits. I like cams with less than 0.560" lift for their safety factor on stock heads/pistons.
Tony
Why split patterns? The longer exhaust duration is helpful if you are running a semi-restrictive exhaust setup, as with stock manifolds and catalytics. If you are running headers, and especially an offroad Y-pipe setup, then there is little to gain from that extra exhaust duration. This is especially true on a stock head motor, or anything else less than 400 rwhp in my opinion.
If you are worried about idle quality, go with more lobe seperation instead. Maybe a 221/221 on a 116 LSA. Choose whatever lift you want, it doesn't affect idle. Just know your limitations on piston/valve clearance issues and your valvespring coil bind limits. I like cams with less than 0.560" lift for their safety factor on stock heads/pistons.
Tony
Re: Split duration vs single pattern cams, and a valve spring question About the springs, Comp 26915 are weak! The Comp 26918 are the newest product and should ALWAYS be used instead.
<img src="images/icons/smile.gif" border="0">
Tony
<img src="images/icons/smile.gif" border="0">
Tony
Thread Starter
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From: Schiller Park, ILL Member: #317
Re: Split duration vs single pattern cams, and a valve spring question Well, I’m going to be running MACs with RT cats and a full catback, so I guess that would be semi restrictive. Random misfire codes don’t matter to me because I’m having the PO300 code removed anyway. So would a split duration still be good for me?
Thanks for the info on the springs! I was planning on the 918s.
Thanks for the info on the springs! I was planning on the 918s.
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From: Dallas,Texas
Re: Split duration vs single pattern cams, and a valve spring question Trending Topics
Thread Starter
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From: Schiller Park, ILL Member: #317
Re: Split duration vs single pattern cams, and a valve spring question [quote]Originally posted by TA_2001:
<strong>Here is an old thread on this topic
captured Feb 2001
http://www.ls1info.com/article.php?sid=124</strong><hr></blockquote>
Wow. That was a lot of info! Thanks <img src="images/icons/smile.gif" border="0">
Problem is it only left me with more questions! I think that my exhaust setup “might” be considered restrictive because I will be using cats, but I will also have headers so it’s a toss up I guess <img src="images/icons/confused.gif" border="0">
About LSA, I wouldn’t mind going down to a 112 as I’m getting custom tuning anyway, but I’m concerned about the huge lifts that all the 112LSA cams seem to have. I’m going to stick with stock heads and a stock intake so I figured that a lift in the .53X area would be good.
Maybe take the Comp 216/220 and drop the LSA to 112? <img src="images/icons/confused.gif" border="0"> I don’t know...
What 112LSA cams are out there with a low (.53X to .54X) lift? And I still need to decide on a split or single duration...
It seems that the 216/220 is making good power as is though, so maybe I shouldn't mess with the LSA?
<strong>Here is an old thread on this topic
captured Feb 2001
http://www.ls1info.com/article.php?sid=124</strong><hr></blockquote>
Wow. That was a lot of info! Thanks <img src="images/icons/smile.gif" border="0">
Problem is it only left me with more questions! I think that my exhaust setup “might” be considered restrictive because I will be using cats, but I will also have headers so it’s a toss up I guess <img src="images/icons/confused.gif" border="0">
About LSA, I wouldn’t mind going down to a 112 as I’m getting custom tuning anyway, but I’m concerned about the huge lifts that all the 112LSA cams seem to have. I’m going to stick with stock heads and a stock intake so I figured that a lift in the .53X area would be good.
Maybe take the Comp 216/220 and drop the LSA to 112? <img src="images/icons/confused.gif" border="0"> I don’t know...
What 112LSA cams are out there with a low (.53X to .54X) lift? And I still need to decide on a split or single duration...
It seems that the 216/220 is making good power as is though, so maybe I shouldn't mess with the LSA?
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Re: Split duration vs single pattern cams, and a valve spring question Single duration are supposed to idle better.
I'm also a fan of the 218/218//114 MMS cam.
Anyone ever done a 540/540/218/218/114/110IC camshaft? I bet that would be a nice idling performer!
RPM, I had a 545/545/221/224/113 Comp that did 375rwhp/410rwtq and the car went 11.7@115mph. Last year.
I'm also a fan of the 218/218//114 MMS cam.
Anyone ever done a 540/540/218/218/114/110IC camshaft? I bet that would be a nice idling performer!
RPM, I had a 545/545/221/224/113 Comp that did 375rwhp/410rwtq and the car went 11.7@115mph. Last year.
Thread Starter
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From: Schiller Park, ILL Member: #317
Re: Split duration vs single pattern cams, and a valve spring question What about a GTP 222/222//.540/.540//112 with stock heads? Any good? Better than the Comp 216/220?
What about the MMS 218 cam? What's the lift and LSA?
[ November 30, 2001: Message edited by: RPM WS6 ]</p>
What about the MMS 218 cam? What's the lift and LSA?
[ November 30, 2001: Message edited by: RPM WS6 ]</p>
Re: Split duration vs single pattern cams, and a valve spring question I think MMS has a 218 cam with a 114 LSA.
222/112 cam will not idle as well. If you are keeping the car wife-friendly I'd say with a 114 or higher.
You may want to check with BradWS6, he had a cam for sale that idled great.
222/112 cam will not idle as well. If you are keeping the car wife-friendly I'd say with a 114 or higher.
You may want to check with BradWS6, he had a cam for sale that idled great.
Thread Starter
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From: Schiller Park, ILL Member: #317
Re: Split duration vs single pattern cams, and a valve spring question PSJ...I'm getting custom tuning anyway to ditch TM and PO300 codes, so I'll be rasing the idle then. I don't mind a lope, I just don't want the thing stalling out and surging. If that means 114, then so be it. But what's the lift on the MMS cam? Is it a compareable cam to the GTP .540/.540//222/222//114 then?
TECH Apprentice
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From: Indianapolis, IN
Re: Split duration vs single pattern cams, and a valve spring question personally I would not worry about lift much. I would look at the 218/224 .537/.537 114LSA cam IRS sells they also have a 216/222 with the same lift and LSA. They are very aggressive lobes and you will like the performance.
LSA has VERY little effect at our power levels really just idle quality really. I have a 112 LSA, its ok, but I bet a 114 would run the same and idle even better.
the TR224 would be my choice since you want programming
LSA has VERY little effect at our power levels really just idle quality really. I have a 112 LSA, its ok, but I bet a 114 would run the same and idle even better.
the TR224 would be my choice since you want programming
Re: Split duration vs single pattern cams, and a valve spring question A few years ago there was concern that 114-115 LSA stuff would make peak too high... I think we have found that the difference from say a 112LSA might only be 200 rpms. And the difference in idle quality is huge IMO for A4 cars.
I'd look at 540-545 lift / 218-222 single duration / 114-115 LSA / 110-112 IC cams for good power, best driveability.
I'd look at 540-545 lift / 218-222 single duration / 114-115 LSA / 110-112 IC cams for good power, best driveability.
Teching In
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From: Nashville, TN
Re: Split duration vs single pattern cams, and a valve spring question [quote]Originally posted by Pro Stock John:
<strong>
Anyone ever done a 540/540/218/218/114/110IC camshaft? I bet that would be a nice idling performer!
</strong><hr></blockquote>
I think that's Bean-o's cam. You can barely hear the cam. I'm talking barely any lope! He has a stage 1 heads, LS6 intake, headers, yadda... and put down 400 rwhp before tunning, through a flowmaster exhaust. Definitely a great street car.
Matt
<strong>
Anyone ever done a 540/540/218/218/114/110IC camshaft? I bet that would be a nice idling performer!
</strong><hr></blockquote>
I think that's Bean-o's cam. You can barely hear the cam. I'm talking barely any lope! He has a stage 1 heads, LS6 intake, headers, yadda... and put down 400 rwhp before tunning, through a flowmaster exhaust. Definitely a great street car.
Matt
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From: Richmond, Va
Re: Split duration vs single pattern cams, and a valve spring question Sounds like you want a hotcam. That has lower lift (.525 i think) and has a 112 lsa. Its also a split duration cam. Not only that, its quite cheap for the kit (~$400 from Pace i think). Check out Raugh's website, he has quite a few comments on the hotcam.
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From: Milford, Ohio
Re: Split duration vs single pattern cams, and a valve spring question The 918s have 25lb more seat and install pressure, otherwise they are the same. Go with the 918s, the 915s are meant as a stock replacement.
On The Tree
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From: Fowlerville, MI
Re: Split duration vs single pattern cams, and a valve spring question The newest issue of Super Chevy magazine has a big in-depth article on cams, valvetrain, etc. Very informative reading!!
D(irecto)r Pepper
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From: Houston Raceway Park...in TEXAS.
Re: Split duration vs single pattern cams, and a valve spring question Most everyone knows my opinion on mid duration-split duration cams.
Here is my web page link that goes to the cam info.
Good luck in your quest of cam knowledge.
http://xs-fx.com/raughammer/cam_info.htm
There is LOTS of reading there....
Here is my web page link that goes to the cam info.
Good luck in your quest of cam knowledge.
http://xs-fx.com/raughammer/cam_info.htm
There is LOTS of reading there....
Re: Split duration vs single pattern cams, and a valve spring question Here's my personal choice, the Lunati 218/221 526/534 114 cam. It has only 3 degrees seperating intake and exhaust duration, mild lift and is on a 114lsa. I put my stock muffler back on for a road trip and I couldn't even tell the cam had a cam and head (JPR stage I) setup.
The car makes good power but without any drivability issues.
The car makes good power but without any drivability issues.