Why all the big tradtional split and not reverse split cams?
07-09-2003, 03:31 PM
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Why all the big tradtional split and not reverse split cams? OK, I thought that our intake (LS1 or LS6) was generally the weakest point in our engines so it would make sense to do a reverse split like 230/227 cam to help the intake and driveability at the same time, but I see so many going with big traditional splits now like g5x2 and such. I am not saying they are bad choices b/c it's obvious they get killer numbers, but what is the reasoning for bigger exhuast than intake?
07-09-2003, 03:45 PM
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Re: Why all the big tradtional split and not reverse split cams? mmmmmmm????? I was pretty sure the reverse split is cams like tr230/227.
So should I definately go with the reverse split like 228/226 or something for my car since it will always be n/a. I also have an a4 with stock heads and 3700 tc. I definately want something with a 112 lsa and bigger than 224/224.
So should I definately go with the reverse split like 228/226 or something for my car since it will always be n/a. I also have an a4 with stock heads and 3700 tc. I definately want something with a 112 lsa and bigger than 224/224.
07-09-2003, 04:44 PM
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Re: Why all the big tradtional split and not reverse split cams? I was never a fan of reverse split. I still like the traditional splits for most setups. The LG style cams are proof enough for me. seems like they make a bit better Tq over a broader area. But without back to back testing on exact same setups...its hard to draw a firm conclusion.
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07-09-2003, 06:47 PM
#10
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Re: Why all the big tradtional split and not reverse split cams? Wrong. You win with properly applied power. This means taking full advantage of where your power is made...regardless of how you choose to define this power. HP is a function of TQ and RPM. It's silly to say that TQ accelerates the car independently of HP. That TQ needs to work to move the car and that's exactly what HP is...working (or you could also say moving) TQ. 
07-09-2003, 07:21 PM
#11
Re: Why all the big tradtional split and not reverse split cams?
Wrong. You win with properly applied power. This means taking full advantage of where your power is made...regardless of how you choose to define this power. HP is a function of TQ and RPM. It's silly to say that TQ accelerates the car independently of HP. That TQ needs to work to move the car and that's exactly what HP is...working (or you could also say moving) TQ.
I'm well aware of the formulas for calculating HP. I guess my point was I think too many people worry about peak HP #s. I'd rather have a nice high flat TQ curve and give up some peak HP. If you make the TQ, the HP will be there, maybe not as high a peak though. I don't have a very high peak HP car, but lots of TQ. I see a lot of cars that have higher peak HP #s than I have and MPH higher, but they can't run the ETs I run. I think to really analyze dyno charts takes some calculus and figuring total area under the curve. Shift points and gearing play a large role in applying the "work" to accelerate the car too. Your explanation is a little hard to follow, but I'm not going to argue with someone that runs in the 9's. 
07-09-2003, 07:44 PM
#12
Re: Why all the big tradtional split and not reverse split cams? On an LS1 with headers, intake does matter more than exhaust.
A reverse split 230/224 will make make more power than a traditional 224/230 when ground on the same lobes and LSA. Extra exhaust duration makes it harder to tune for idle and cam surge. On an LS1 with a good exhaust, A 232/228 112 will make almost as much power as a 232/236 112, but will be easier to tune just off idle and have less fuel smell at a 900 rpm idle. Low rpm torque on the reverse may even exceed the traditional split so stop & go driving may be slightly better with the reverse split.
As a practical matter, most people who do not have notched pistons are limited to about 232* intake duration. If you want to squeeze the last few HP out of the car, upping the exhaust duration a bit can sometimes help and that is what LG did.
A reverse split 230/224 will make make more power than a traditional 224/230 when ground on the same lobes and LSA. Extra exhaust duration makes it harder to tune for idle and cam surge. On an LS1 with a good exhaust, A 232/228 112 will make almost as much power as a 232/236 112, but will be easier to tune just off idle and have less fuel smell at a 900 rpm idle. Low rpm torque on the reverse may even exceed the traditional split so stop & go driving may be slightly better with the reverse split.
As a practical matter, most people who do not have notched pistons are limited to about 232* intake duration. If you want to squeeze the last few HP out of the car, upping the exhaust duration a bit can sometimes help and that is what LG did.
07-09-2003, 08:18 PM
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Re: Why all the big tradtional split and not reverse split cams?
Wrong. You win with properly applied power. This means taking full advantage of where your power is made...regardless of how you choose to define this power. HP is a function of TQ and RPM. It's silly to say that TQ accelerates the car independently of HP. That TQ needs to work to move the car and that's exactly what HP is...working (or you could also say moving) TQ.
I'm well aware of the formulas for calculating HP. I guess my point was I think too many people worry about peak HP #s. I'd rather have a nice high flat TQ curve and give up some peak HP. If you make the TQ, the HP will be there, maybe not as high a peak though. I don't have a very high peak HP car, but lots of TQ. I see a lot of cars that have higher peak HP #s than I have and MPH higher, but they can't run the ETs I run. I think to really analyze dyno charts takes some calculus and figuring total area under the curve. Shift points and gearing play a large role in applying the "work" to accelerate the car too. Your explanation is a little hard to follow, but I'm not going to argue with someone that runs in the 9's. 
07-09-2003, 09:38 PM
#14
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Re: Why all the big tradtional split and not reverse split cams? "I'd rather have a nice high flat TQ curve and give up some peak HP. If you make the TQ, the HP will be there, maybe not as high a peak though."
Well said. One might also say that a nice high flat TQ curve is alot of easily usable HP. It explains why your average large CI engine making a peak of 475 RWHP will normally stomp a hot smaller CI engine that makes 500 RWHP. The larger CI engined car made use of more HP over the average of the run despite having a lower peak.
Torque in itself does not equal quick or fast since TQ alone does no work (work requires movement.) Once we start talking about TQ at a given RPM, we're saying the same thing as a given HP.
Anyway, we're saying the same thing.
Well said. One might also say that a nice high flat TQ curve is alot of easily usable HP. It explains why your average large CI engine making a peak of 475 RWHP will normally stomp a hot smaller CI engine that makes 500 RWHP. The larger CI engined car made use of more HP over the average of the run despite having a lower peak.
Torque in itself does not equal quick or fast since TQ alone does no work (work requires movement.) Once we start talking about TQ at a given RPM, we're saying the same thing as a given HP.
Anyway, we're saying the same thing.
07-09-2003, 09:47 PM
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Re: Why all the big tradtional split and not reverse split cams?
On an LS1 with headers, intake does matter more than exhaust.
A reverse split 230/224 will make make more power than a traditional 224/230 when ground on the same lobes and LSA. Extra exhaust duration makes it harder to tune for idle and cam surge. On an LS1 with a good exhaust, A 232/228 112 will make almost as much power as a 232/236 112, but will be easier to tune just off idle and have less fuel smell at a 900 rpm idle. Low rpm torque on the reverse may even exceed the traditional split so stop & go driving may be slightly better with the reverse split.
As a practical matter, most people who do not have notched pistons are limited to about 232* intake duration. If you want to squeeze the last few HP out of the car, upping the exhaust duration a bit can sometimes help and that is what LG did.
A reverse split 230/224 will make make more power than a traditional 224/230 when ground on the same lobes and LSA. Extra exhaust duration makes it harder to tune for idle and cam surge. On an LS1 with a good exhaust, A 232/228 112 will make almost as much power as a 232/236 112, but will be easier to tune just off idle and have less fuel smell at a 900 rpm idle. Low rpm torque on the reverse may even exceed the traditional split so stop & go driving may be slightly better with the reverse split.
As a practical matter, most people who do not have notched pistons are limited to about 232* intake duration. If you want to squeeze the last few HP out of the car, upping the exhaust duration a bit can sometimes help and that is what LG did.
07-09-2003, 09:56 PM
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Re: Why all the big tradtional split and not reverse split cams? Woah...I just had a flashback! The Colonel involved in a discussion on TQ vs HP!?!?! We just need ChrisB and a few others and this thread could get to be 5 pages 
07-09-2003, 10:27 PM
#17
Re: Why all the big tradtional split and not reverse split cams? Would the exhaust choice, as in how free flowing it is, impact whether a reverse, straight up, or traditional cam be better? I would tend to think that cars with free flowing exhaust could get more from a reverse split, while a car running cats might like a traditional cam with more exhaust duration.
07-10-2003, 12:17 AM
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Re: Why all the big tradtional split and not reverse split cams? Wow, thanks for all the comments guys. Very interesting stuff.
That is what i was thinking as well.
Also, how do heads come into play when selecting a cam? I'm not talking about PVC or stuff like that but strictly choosing the right cam duration/lift/lsa on a stock head vs. a aftermarket head? It seems to me like they are independent of each other and the ported heads just allow more power, am I wrong or do the heads factor in as well?
Would the exhaust choice, as in how free flowing it is, impact whether a reverse, straight up, or traditional cam be better? I would tend to think that cars with free flowing exhaust could get more from a reverse split, while a car running cats might like a traditional cam with more exhaust duration.
Also, how do heads come into play when selecting a cam? I'm not talking about PVC or stuff like that but strictly choosing the right cam duration/lift/lsa on a stock head vs. a aftermarket head? It seems to me like they are independent of each other and the ported heads just allow more power, am I wrong or do the heads factor in as well?
07-10-2003, 02:57 AM
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Re: Why all the big tradtional split and not reverse split cams? I'd be curious to see a car with flycutted pistons running the same specs as the G5X2 on a reverse split...
i.e. 240/232 .612/.610 or something like that.
I'm sure it'd make plenty o power
i.e. 240/232 .612/.610 or something like that.
I'm sure it'd make plenty o power
07-10-2003, 07:43 AM
#20
Re: Why all the big tradtional split and not reverse split cams? 98: I would agree that a free flowing exhaust favors a single pattern or reverse when making a power vs. drivability trade-off. If you're keeping the stock exhaust manifold and cats, the traditional split cams work well and, IMO, this is why the LS6 cam, most LPE cams, and gm hotcam are traditional split.