Reverse split cams
Reverse split cams What is the concept of reverse split cams?
Advantages/disadvantages? How can one, FOR EXAMPLE, take a 227/224 .569/.563 114 LSA and create more power, and how should heads, intake, etc. be matched to such a cam?
I have searched and seek more resources to learn more of this...
-G (jet engine mechanic)
Advantages/disadvantages? How can one, FOR EXAMPLE, take a 227/224 .569/.563 114 LSA and create more power, and how should heads, intake, etc. be matched to such a cam?
I have searched and seek more resources to learn more of this...
-G (jet engine mechanic)
More like how the exhaust, and headers be matched to it.
The concept is to have high flowing exhaust ports and system and make more TQ because you open the exhaust valve later and allow the motor to fully use the power stroke.
Usually if a reverse split works the best you need to fix your induction system. If your not rules limited then someone screwed up.
Bret
The concept is to have high flowing exhaust ports and system and make more TQ because you open the exhaust valve later and allow the motor to fully use the power stroke.
Usually if a reverse split works the best you need to fix your induction system. If your not rules limited then someone screwed up.
Bret
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You can't just look at the duration at .050" to determine whether the cam's a reverse split, you also have to look at the duration at .006" and .200".
For example, the popular FMS F-13 cam: 230/232 112LSA
Duration at .200" lift is 150/148, meaning the intake lobe has more duration than the exhaust.
Or take my cam, the Thunder Racing TRak cam: 233/235 112LSA
Duration at .006 is 285/285 making it look like a single pattern cam.
Duration at .050" is 233/235 making it look like a forward split.
Duration at .200" is 157/155 making it look like a reverse split.
I think no one would deny that it's a good cam in my application.
For example, the popular FMS F-13 cam: 230/232 112LSA
Duration at .200" lift is 150/148, meaning the intake lobe has more duration than the exhaust.
Or take my cam, the Thunder Racing TRak cam: 233/235 112LSA
Duration at .006 is 285/285 making it look like a single pattern cam.
Duration at .050" is 233/235 making it look like a forward split.
Duration at .200" is 157/155 making it look like a reverse split.
I think no one would deny that it's a good cam in my application.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
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11 Second Club
Joined: Oct 2004
Posts: 418
Likes: 0
From: Pembroke Pines,FL
I run the TR227 cam you mention. I went over my set up & goal with Thunder racing & they suggested a reverse split cam. Actually they suggested the TR230 but with all the hype on 114 with auto's I went on the safe side & got the TR227. I have a good flowing exhaust & plan on staying NA. Currently im setting up to do heads (TEA 5.7 stg-1) that should put me to my new goal of 11.30's. I should be able to hit 11.50's now if I get to the track with some cooler weather (11.63 with +1000 DA/80 degrees). There are alot of good cam's out there, It's not easy to make a choice. But I have had good luck & no driveablity issue with this one.
i have the 230/224 with the lsa 111 basic bolt ons like ls6 intake asp pulley and full exhaust and this cam i put 375 hp at the wheels torque was like 380 at the wheels here is the dyno sheet
Last edited by mattslightning; Jan 28, 2006 at 03:44 PM. Reason: added dyno sheet
for those of u with the TR227....how is the lope of that cam...strickly as far a sound goes... does it sound mean...or what. how does it sound in comparison to the tr230. what is ur lsa's. ive heard ALL the ls1sounds sounds so please dont refer me there....thansk
FormerVendor
Joined: Dec 2001
Posts: 2,444
Likes: 2
From: WWW.SPEEDINC.COM
If driveability is a concern (which I believe it always should be), I generally prefer single pattern cams up to around 225 @.050.
I think a reverse split is useful when you are trying to extend the rpm range without sacrificing driveability, and the way I go about it is closing the exhaust valve a bit early to minimize overlap.
I don't remember the valve events, (I have them written down at work), but as an example, this is a cam I spec'd for larrys zo6 (here at speed inc).
Duration was 228/222 @ .050. The car is an 02 Zo6, with a blackwing (or similar air filter), stainless works headers/y-pipe, no cats, zo6 catback, stock heads/intake/tb.
Driveability is very nice, though there is a detectible lope at idle.
http://www.ls1speed.com/pictures/si007.jpg
I think a reverse split is useful when you are trying to extend the rpm range without sacrificing driveability, and the way I go about it is closing the exhaust valve a bit early to minimize overlap.
I don't remember the valve events, (I have them written down at work), but as an example, this is a cam I spec'd for larrys zo6 (here at speed inc).
Duration was 228/222 @ .050. The car is an 02 Zo6, with a blackwing (or similar air filter), stainless works headers/y-pipe, no cats, zo6 catback, stock heads/intake/tb.
Driveability is very nice, though there is a detectible lope at idle.
http://www.ls1speed.com/pictures/si007.jpg
11 Second Club
Joined: Oct 2004
Posts: 418
Likes: 0
From: Pembroke Pines,FL
Originally Posted by Turbo LS1 SS
for those of u with the TR227....how is the lope of that cam...strickly as far a sound goes... does it sound mean...or what. how does it sound in comparison to the tr230. what is ur lsa's. ive heard ALL the ls1sounds sounds so please dont refer me there....thansk
I think we're kind of getting away from the technical aspects of this question with people just posting that they have a reverse split and made so and so hp/tq. SStrokerAce makes a good point about people getting reverse splits b/c they work better for them in terms of hp/tq under the curve (because they have a really free flowing exhaust system and only a mediocre intake system). When the exhaust flows well (LT/ORY sorta setup), you can utilize the power stroke more, as stated, by delaying the exhaust valve opening. You can delay this opening AND use a shorter duration b/c the exhaust is going to flow faster/more efficiently out of the chamber with the free flowing exhaust setup. Bottom line, you should note that it is not a set rule that reverse splits make more power or tq under the curved, it is just one of the better types of cams for those (generally many) who focus more on exhaust flow (headers, y-pipe, and on back) than intake flow (generally just add a ported tb/ls6 intake and call it a day). In the case of 90/90 setups and a good set of heads you will see that reverse splits aren't as beneficial.
I have a 232/228 573 571 waiting to go in my car, my buddy ran 11.20 cam only with mac's and true duals. I have LTs/O/R Y,Catback but hopefully it should run fairly close to what his did with it.
I've always seen reverse split cams do well on forced induction motors w/o the spray. these motors already have a strong exhaust output, they like to suck in the air however.
Patrick G. Is there anyway to find the specs @ .006 and .200 of a cam w/ only specs showing at .050
Patrick G. Is there anyway to find the specs @ .006 and .200 of a cam w/ only specs showing at .050
Originally Posted by 02WS6Bird
Patrick G. Is there anyway to find the specs @ .006 and .200 of a cam w/ only specs showing at .050
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
