standard or reverse split?
standard or reverse split? ok so i am gunna order my cam this week, i have pretty much everything else i need, except the cam. i plan on spraying later in the future. my car will be Daily driven and should have good street mannners. Goal is about 440ishrwhp.. Thanks
-Ryan
-Ryan
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
When you choose a cam, choose it for your NA application. Unless this is a nitrous drag Queen.
You can use ANY cam up to ~150 rwhp shot.
I have a Stealth II 224/220, .581/.581 116+0 lsa, and I've sprayed 200 dry on it for a year and many passes.
Finally spun a rod bearing, but never had any issues with N2O (properly tuned).
You can use ANY cam up to ~150 rwhp shot.
I have a Stealth II 224/220, .581/.581 116+0 lsa, and I've sprayed 200 dry on it for a year and many passes.
Finally spun a rod bearing, but never had any issues with N2O (properly tuned).
well said man 
think about how much driving u will actually be doing under spray. not a whole lot compared to the rest of the time on the street. so pick a cam that will build u a kick *** n/a motor. and like predatore said, u can spray up to 150 shot w/o having to worry about the split pattern. im in the middle of choosing a cam too, and ive decided im not gonna let the n20 factor swat my decision. i wont get a reverse split, but i may stick with a single pattern....like maybe the torquer.
think about how much driving u will actually be doing under spray. not a whole lot compared to the rest of the time on the street. so pick a cam that will build u a kick *** n/a motor. and like predatore said, u can spray up to 150 shot w/o having to worry about the split pattern. im in the middle of choosing a cam too, and ive decided im not gonna let the n20 factor swat my decision. i wont get a reverse split, but i may stick with a single pattern....like maybe the torquer. thanks alot guys...i am going to call MTI today and ask em what they recommend for the heads..figured it be best just to ask em =D and i wont be sprayin over 150, im on stock bottom end it would be 100 at the very most and only at the track (or if some1 really needs to get punked on the street 
)
) For either a traditional split is the way to go in my opinion. Only makes sense. The intake always flows better then that of an exhaust so crutch it by using more exhaust duration. Also, hot exhaust gases take up much more room and are much harder to get rid of so use more duration to help. If you want to sacrifice power for drivability then I may understand the reverse split be there is no other reason to use it in my opinion. The ls1 or ls6 intake do not limit the intake flow enough to warrant it either.
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Originally Posted by VaNDaL*SS*
thanks alot guys...i am going to call MTI today and ask em what they recommend for the heads..figured it be best just to ask em =D and i wont be sprayin over 150, im on stock bottom end it would be 100 at the very most and only at the track (or if some1 really needs to get punked on the street )
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Originally Posted by DAPSUPRSLO
For either a traditional split is the way to go in my opinion. Only makes sense. The intake always flows better then that of an exhaust so crutch it by using more exhaust duration. Also, hot exhaust gases take up much more room and are much harder to get rid of so use more duration to help. If you want to sacrifice power for drivability then I may understand the reverse split be there is no other reason to use it in my opinion. The ls1 or ls6 intake do not limit the intake flow enough to warrant it either.
I will have to humbly disagree. The exhaust has a lot more energy to help it get out than the intake does to get in. As I said in the other thread the optimum exhaust lobe is the one that opens the valve early enough to properly scavenge the cylinder but does not open so early as to blow useful energy out the exhaust pipes that could be used to push the piston down.
Saying that reverse splits don't work is like saying that the Comp 216/220 is the perfect LS1 cam. In certain instances this might be true, but in other instances it is wrong. It totally depends on the combination of parts and the intended use of the engine. For the record the other day we just sold a cam to an engine builder using a supercharged Big Block Chevy running on alcohol: Guess what? It was a reverse split.
If the car is a street car with a typical street exhaust I personally would look to a slight conventional split based on using nitrous. In other words a slight forward split won't hurt anything in that application but could definitely help on the juice.
Thanks for the Geoff, for my app what cam would u recommend. The car is daily driven so it must keep a certain level of drivability. I am in Cali and we have smog ****'s up the wazoo but im not concerned with that (i have a couple hook ups) The cam i am looking into is a 228/232 .588/.575 lsa113 or your TR230...keep in mind the heads are milled .030. Thanks
-Ryan
-Ryan
Originally Posted by Geoff
I will have to humbly disagree. The exhaust has a lot more energy to help it get out than the intake does to get in. As I said in the other thread the optimum exhaust lobe is the one that opens the valve early enough to properly scavenge the cylinder but does not open so early as to blow useful energy out the exhaust pipes that could be used to push the piston down.
Saying that reverse splits don't work is like saying that the Comp 216/220 is the perfect LS1 cam. In certain instances this might be true, but in other instances it is wrong. It totally depends on the combination of parts and the intended use of the engine. For the record the other day we just sold a cam to an engine builder using a supercharged Big Block Chevy running on alcohol: Guess what? It was a reverse split.
If the car is a street car with a typical street exhaust I personally would look to a slight conventional split based on using nitrous. In other words a slight forward split won't hurt anything in that application but could definitely help on the juice.
Saying that reverse splits don't work is like saying that the Comp 216/220 is the perfect LS1 cam. In certain instances this might be true, but in other instances it is wrong. It totally depends on the combination of parts and the intended use of the engine. For the record the other day we just sold a cam to an engine builder using a supercharged Big Block Chevy running on alcohol: Guess what? It was a reverse split.
If the car is a street car with a typical street exhaust I personally would look to a slight conventional split based on using nitrous. In other words a slight forward split won't hurt anything in that application but could definitely help on the juice.
I'm interested in your thought process Geoff, that's all. We have had more then a few cam discussions over the phone.
Originally Posted by DAPSUPRSLO
Is the alcohol example because it takes so much fuel to air that a large intake duration is required? A/F ratios with alcohol can approach 3 to 1. I would still think the reverse split will improve lower range power and driveability at the sacrifice of all out power. At high rpms where all out power is made the reverse split may not have enough exhaust duration to get out the exhaust charge and may experience blow down loss unless it has an extremely large lsa opening the exhaust valve earlier given the same icl which looses the benefits of scavenging. At high rpms with the traditional split scavenging will assist the intake process which will aid the intake side of things do to the ability to have more overlap without sacrificing exhaust opening points.
I'm interested in your thought process Geoff, that's all. We have had more then a few cam discussions over the phone.
I'm interested in your thought process Geoff, that's all. We have had more then a few cam discussions over the phone.
The alcohol example is because of the burn rate of the fuel. The alcohol burns slower than gasoline. Because of this delaying the exhaust opening makes a lot of sense. Nitromethane would be an extreme example of a slow burning fuel. As we discussed in the other thread there is an optimum point for the piston to be at in the bore... the slower the fuel burns the further toward BDC the piston can be at.
All things being equal, meaning the intake lobe and it's associated opening and closing points, and overlap, with the exhaust closing point running a reverse split (later exhaust opening) should bolster low end torque if not overdone with a minimal affect on top-end. This of course assumes you have a high flowing exhaust in place to take advantage of this.
I have seen a ton of arguments against running a reverse split cam, from they don't make any low end to they don't make any top end to they don't work with nitrous. All of these arguments have some merit but unfortunately just because a certain cam behaves a certain way that happens to be a reverse split means all reverse split cams are branded by people who aren't analyzing ALL of the valve events. Lets just say that with the T-Rex a lot of testing was done, including with reverse splits and some of the data that we gathered would surprise a lot of 'experts' on this board.
I definitely like talking about this stuff, since it is something I am presently very involved with.
