Why use a reverse split Cam?
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Joined: Jan 2004
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From: Dayton, Ohio
Why use a reverse split Cam? What are the advantages of a reverese split cam? I am looking at the Thunder 230/224 575/563 111LSA. I understand the lift and LSA, not the reverse split. Thanks id advance.
Reverse split means there is more intake duration than exhaust. It's great for cars w/ free flowing exhaust. I've got that cam and put down 395/377. People say its got the driveability of the tr224/224 (I've never driven a car w/ that cam so i can't comment) but the driveability of it is very good. Oh and it sounds like you've got a monster under the hood w/ that cam. Its a great cam and i highly recommend it!
Heres my comparison dyno of before/after the cam:
Heres my comparison dyno of before/after the cam:
Same cam here, I love mine. Gained 90rwhp with the cam and the other bolt on's. Drives pretty well really, some surging off idle but no big deal. Sounds wicked. I'm thinking of getting a cutout 
i just picked up a 99z 6 spd. this cam looks good to me. i was gonna get the TR224 but if this one has more power and drives the same ill get it.
will it work well with heads too.
will it work well with heads too.
If you have heads that flow very well on the exhaust side, you can get away with a reverse split cam. Less duration means more low end and midrange. But bear in mind that on a stock head, the exhaust side is usually weak flowing. The factory does this to maximize low end and midrange, at least to an extent.
Jason
Jason
The graph above shows why I wouldn't use one. It dosen't gain much of anything until 4500 rpm's or so. Why leave power on the table when you don't have to. I reccomend the Thunder 230/236 if your looking for something in that size range. I have the freest flowing exaust ever and have never thought once about putting in a reverse split. Just no need unless your turbo'd IMO.
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Originally Posted by FstBlkz28
Reverse split means there is more intake duration than exhaust. It's great for cars w/ free flowing exhaust. I've got that cam and put down 395/377. People say its got the driveability of the tr224/224 (I've never driven a car w/ that cam so i can't comment) but the driveability of it is very good. Oh and it sounds like you've got a monster under the hood w/ that cam. Its a great cam and i highly recommend it!
Heres my comparison dyno of before/after the cam:
Heres my comparison dyno of before/after the cam:
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Originally Posted by Adrian87GN
No way, down low it feels great! I still have stock 3.42's too and it really is stronger down low and midrange, but really just rips at 4500 to 6800 or so!
My TR230 makes tons of torque at anything above 2000 rpm. Idle is a little choppy, but I also have it set at 850 running thru dual sweet thunders that dump before the axle to scare away rice. My EFI live tune is working really well and hot start problems and surging are a thing of the past. Keep in mind that a good tune is required for the TR230 to perform well. Mine has stage 2 Absolute speed heads and because the car is so light it will ignite the tires in 4th gear above 45 mph if I hit it hard (tires are 195 70 14's). I love my TR230.
FWIW there is a member here that was making 440 rwhp with about the same setup.
FWIW there is a member here that was making 440 rwhp with about the same setup.
Originally Posted by Beast96Z
I'm sure it does. You did gain more power than a stock cam, but your still not pushing what you could down low. I'm sure you saw the graph above. A little more power, but not much of nothing compared to a traditional split cam. Look at this graph comparing the TR224, the TR 227/224, and the TR 230/224. All of the graphs are the same until 5k or so. There's no reason not to gain low-end power when swapping cams. The reverse cams just hender the exaust to a point to where they can't move enough air, thus not making any more power that it's smaller counter parts.
Bullshit. Sorry to come across as harsh but the low end torque characteristics of the TR230 has NOTHING to do with the fact that is a reverse split. It has everything to do with the amount of overlap it has and where it is in relationship to TDC. As I have said in the past the main point of a reverse split cam is to hold pressure on the power stroke longer before opening the exhaust valve. By doing this you can gain power in an application that has relatively low compression and a freeflowing exhaust. By low compression I am talking under 11 to 1.
I can easily grind another reverse split cam that will have a lot more lowend, but that wasn't the point of the TR230. It's claim to fame is the fact that is has a very broad smooth power-band.
Originally Posted by Beast96Z
The graph above shows why I wouldn't use one. It dosen't gain much of anything until 4500 rpm's or so. Why leave power on the table when you don't have to. I reccomend the Thunder 230/236 if your looking for something in that size range. I have the freest flowing exaust ever and have never thought once about putting in a reverse split. Just no need unless your turbo'd IMO.
Under the curve i am making almost 350tq @ 2700 while the 233 ismaking less than 300tq. We peak about the same but i have way more avg tq. Hp the 233/239 peaks almost 20hp higher at about 300 higher rpm. So when deciding you have decide if you want high peak and no mid or good mid and good peak.
link to 233/239 graph
https://ls1tech.com/forums/dynamometer-results-comparisons/402305-prc-5-3-stage-2-5-tsp-233-239-cam.html
Originally Posted by Geoff
I can easily grind another reverse split cam that will have a lot more lowend, but that wasn't the point of the TR230. It's claim to fame is the fact that is has a very broad smooth power-band.
TXhorns281 cam only TR230 full bolt on. once again flat as a 13 yr old.
https://webspace.utexas.edu/wl333/lastdyno.jpg
https://webspace.utexas.edu/wl333/lastdyno.jpg
Originally Posted by Geoff
Bullshit. Sorry to come across as harsh but the low end torque characteristics of the TR230 has NOTHING to do with the fact that is a reverse split. It has everything to do with the amount of overlap it has and where it is in relationship to TDC. As I have said in the past the main point of a reverse split cam is to hold pressure on the power stroke longer before opening the exhaust valve. By doing this you can gain power in an application that has relatively low compression and a freeflowing exhaust. By low compression I am talking under 11 to 1.
I can easily grind another reverse split cam that will have a lot more lowend, but that wasn't the point of the TR230. It's claim to fame is the fact that is has a very broad smooth power-band.
I can easily grind another reverse split cam that will have a lot more lowend, but that wasn't the point of the TR230. It's claim to fame is the fact that is has a very broad smooth power-band.
To me, by looking at the graph I posted on the first page, which came from your shop, the cams do not seperate until 5k or so. If the cams are meant to be that way, then that's good, but I would think that it would need to be mentioned that that is what they are for. All I've ever had to go on is the graph I posted, which is about the best comparison you could get. To me, if I swap cams, I'd like to gain power below 5k as well as above. I think that is where your TR 230/236 falls in. Would you happen to have a graph with it overlaid with the 230/224? It would be nice to see a comparison with the same intake durations and equal splits in oppisite directions. Thanks
Originally Posted by Beast96Z
The graph above shows why I wouldn't use one. It dosen't gain much of anything until 4500 rpm's or so. Why leave power on the table when you don't have to. I reccomend the Thunder 230/236 if your looking for something in that size range. I have the freest flowing exaust ever and have never thought once about putting in a reverse split. Just no need unless your turbo'd IMO.
Originally Posted by FstBlkz28
From the graph's I've seen of other traditional splits that hit 400.... they LOSE power in the low end. This cam gained power all throughout the powerband. IMHO, if the cam doesn't lose power anywhere, but gains power from the get-go. Why the hell wouldn't you want it? Unlike most of the other cams that hit 400 which have weaker low-ends than the stock cam.
Originally Posted by Beast96Z
Don't worry about the harshness, I get way worse stuff than that at work every day. To me, by looking at the graph I posted on the first page, which came from your shop, the cams do not seperate until 5k or so. If the cams are meant to be that way, then that's good, but I would think that it would need to be mentioned that that is what they are for. All I've ever had to go on is the graph I posted, which is about the best comparison you could get. To me, if I swap cams, I'd like to gain power below 5k as well as above. I think that is where your TR 230/236 falls in. Would you happen to have a graph with it overlaid with the 230/224? It would be nice to see a comparison with the same intake durations and equal splits in oppisite directions. Thanks
To me, by looking at the graph I posted on the first page, which came from your shop, the cams do not seperate until 5k or so. If the cams are meant to be that way, then that's good, but I would think that it would need to be mentioned that that is what they are for. All I've ever had to go on is the graph I posted, which is about the best comparison you could get. To me, if I swap cams, I'd like to gain power below 5k as well as above. I think that is where your TR 230/236 falls in. Would you happen to have a graph with it overlaid with the 230/224? It would be nice to see a comparison with the same intake durations and equal splits in oppisite directions. ThanksI will work on that comparison.
You have been on this board long enough to know a little something about valve events. Bottom line is that if you look at the amount of overlap and where it is in relationship to TDC, our 230/236 will definitely make more PEAK power, but not necessarily more area under the curve. Again based on past testing either of these cams could be either forward or reverse split and basically do the same as they are already doing. EVERY internet 'expert' knows the reverse split 'doesn't work' so we made this one a forward split. IMHO the exhaust opening point is probably the least sensitive parameter for a properly tuned header system on a street motor. Your mileage may vary, J/K .