Brice Peters

Somehow my plan to just put the UPP kit on, turned into a full valve train upgrade as well. Was thinking of going for a reverse split but wanted to hear some opinions. I've seen a few people saying they were putting one in or wanted to put one in, but haven't seen much from people who have done. So anybody one here put one in on there turbo build, or better yet, someone make the switch from a normal split? Any and all opinions wanted, thanks!

Chris Stewart

I ran the Comp Cams LSR Turbo on my TTiX 347, it's a reverse split. They make 2 of them, I have the smaller one. It's pretty mild.

54-480-11
.610 lift, 227/223

54-481-11
.620 lift, 235/231

If I was doing it again like to try the bigger one for more top end, and more aggressive idle. The setup made good power though, 900-1000rwhp.

SBCGENII

You won't need a reverse split. The low exhaust duration on a revrse split is to help with back pressure. If you are runing decent size twins and a small duration exhaust lobe or move the EVO to late you will just hurt spool.

Chris Stewart

I'm no expert but thought the reverse split was to help spool remote mount turbos, but still works good with front mounts.

SBCGENII

Reverse splits came long before rear mounts. There might have even been NA LS1 reverse split cams before STS came out.

SBCGENII

All that maters is that the IVC and EVO are close. Getting those close provide the majority of power and spool.

JoeyG

In my turbo ttuck I thought I needed a reverse split originally, so I used an SLP 234/228 113 cam I had lying around. It made decent power, but swapping to an Isky 212/212 gained me over 60#/ft and 40+hp down low in my 01 rcsb 5.3 with a PT88.

SBCGENII

Big difference in IVC. Big difference in overlap too. How did the top end change? I would assume the engine would like the smaller cam better on top end aswell with the compressor/turbine combo.

JoeyG

Whole powerband increased, biggest improvement was the midrange and bottom end response, which my pig truck needed. Idle was good with both cams, but 212 does have better vacuum and less aggressive ramp rates.

SBCGENII

I would like to try one of those cams. Maybe get a fraction of the performance stock48 got and I would be happy lol.

JoeyG

I use his stage 2 cam (218/222) in the vette and one of his truck torque (210/216 110) cams in my 4.8 swapped 94 k1500 truck as well. Phil97Svt was kicking *** in his LS piwered Mustang with a rev split at one time I believe too.

SBCGENII

Phil was one of the guys that made ls1tech great.

If I get a t6 Borg I wouldn't mind trying a 215 with 38-40 IVC and 230 with a 55 ish EVO for possibly the best of both worlds.

5 Liter Eater

As mentioned it's not so much about the reverse split that makes a turbo cam, it's minimizing/eliminating overlap. The kits for our cars do tend to have decent to obscene amounts of backpressure.


The cam I had in my TTIX 408:



Then when I went LSX I went a bit bigger, still keeping overlap at bay. This is now on my twin 72 UPP LSX.



I'm now LS7 top end so the lifts are higher with the 1.8:1 rockers.


Not saying either of these is the bee's knees but examples of turbo cams.


For reference you can SWAG the overlap easily by averaging the duration and subtracting the LSA x 2. Positive numbers mean overlap, zero or negative is not.


FWIW if that last cam doesn't make power with the new top end I'm throwing away everything I think I know about turbo cams and putting in something that makes power NA like the BTR stage 3 LS7 NA cam; 238/250 .652"/.630" 113+3

Brice Peters

Nice, lots of good info here. Appreciate it guys!


The kit will be ran at 8psi on e85 with a SD tune for the foreseeable future. Using the stock exhaust and no cats. Engine will be stock cubes. If you guys had an option for a new cam, what would you put it in if you had my setup?

SBCGENII

http://www.briantooleyracing.com/twi...ge-ii-cam.html

StatmanRN

[QUOTE=Chris Stewart;1592060107]I ran the Comp Cams LSR Turbo on my TTiX 347, it's a reverse split. They make 2 of them, I have the smaller one. It's pretty mild.

54-480-11
.610 lift, 227/223

Thats the exact cam I will be running [already have it, but stock for now]with STS rearmounts and upgraded turbos

With Cam selection, its always about what you want it to do. For me? Not going to make it an all out drag car, my goal is all around performance with a near stock idle and good response

In the past I played with a lot of carbed turbo setups. Found they always worked best with wide LSAs, minimal overlap, and reverse split cams on the street. Mind you these were low compression [7.7-9:1] with no electronic controls. Whole different ball game today with injection and control systems and still learning a lot.