rgvsierra

iTrader: (7)

did i hear reverse split? i run it and like it..

02sierraz71_5.3

iTrader: (2)

I agree on the fighting the intake, I really think it flows very well in its power band. The point I was trying to make is that our style intakes work great in thier band and half of that range is cut with big stalls so its a fine line with a cam it has to be matched with little room for leway, thats why specific cams like the TR220-224 keep popping up as top achievers.

I like sportsides reverse splits I just dont like the idea when you start using them with big stalls and paired with our intakes. People seem to complain about our intakes but I really believe they are the best of both worlds, whereas with old school you got to pick do I want it down low or up top with ours we've got a 5000rpm band. People complain about em when its not uncommon to hear about an ls6 intake supporting over 450+RWHP NA thats ******* huge if you had said that GM would be mass producing an engine that can support 550crankpower 10 years ago with a cam and some headers people would have told you to put the pipe down.
On top of it these engines take up the same space that many other manufacturers V6's use and they are 100lbs lighter than BMW's 10 cylinders that displace less. I could go on but I digress.
Here is an excerpt from an article on the L92
"We've spent a lot of time talking about intake manifolds during these engine posts, and for good reason - port fuel injection has allowed the development of some pretty radical intake geometry, and as such, intake manifolds may have overtaken cylinder heads as the most critical contributor to an engine's powerband.

Like we've seen on most other engines that are designed for something just short of all-out top-end performance, here we find the barrel-shaped long-runner manifold. There's plenty of plenum volume, and a not-outrageously-large runner cross-section. In other words, this is exactly what we'd expect to see on an engine designed to have a broad powerband that's biased somewhat towards the lower end. "
http://www.autoblog.com/2006/02/21/g...nes/1#comments

Id be interested to see one of sportsides cams with a stock stall+boltons and the truck intake.

Kano

iTrader: (3)

i agree,
I bet if you took a avg most guys on here run a 3000 TC
now granted most time is spent around 4500 thru thr 1/4

but that initial hit off the line helps that 60' which helps at the big end
ex bluecajun cuts a 1.7 and runs 12.5 5.3L tr220
slowprocess cuts a 1.9 and runs a 12.5 6.0L tr224
I think its a good example of how important that 60 and launch is

camshaft selection is impotant
It must match everything in your setup and not fight the intake or itself

02sierraz71_5.3

iTrader: (2)

This has really got me thinking about setups and where the reverse split cams come into play for NA applications. Alot of people have great luck with them and the graphs look good, they idle well and would probably work well with even the factory air box installed. I know in the end its all about the setup.

Id like to hear the rational behind the intake bias.

Im looking at it like this: .050 duration
224/230 111/111+0(LCA/ICL+advance)
IVO 1.0 IVC 43
EVO 46 EVC 4.0

230/224 111/111+0
IVO 4.0 IVC 46
EVO 43 EVC 1.0

with the exhaust bias it closes the intake valve earlier more DCR and power down low, plus the overlap period makes more hp up top. Is my thinking off?

Sport Side

iTrader: (6)

The rational is that a given intake lobe will only need so much exhaust to make the most average power across a rpm spectrum. Meaning the exhaust VEs need to be paired up correctly with the intakes.

Shaun (93Pony) :
In my opinion, the exhausts opening point is not the least important. For far too long the major camshaft companies have stated that the exhaust lobe is the least important. Well, they are wrong and my camshafts are proof of this. The most important lobe used in my camshaft designs is the exhaust lobe. The exhaust valve events (VE’s) are what it comes down to. If you open the ehxuast too early you loose heat and velocity through the exhaust runners. Opening the exhaust valve too late will not let all of the exhaust gases escape which can contaminate the intake charge, drastically affecting power. The exhaust valve opening point must be timed perfectly for everything to work properly.
In other words, the intake valve closing (IVC) must be paired correctly with the exhaust valve opening (EVO) point and the intake valve opening (IVO) must be correctly paired with the exhaust valve closing (EVC).

onebadrubi

Im not nowere to be found in this argument but want to throughout another question. FOR NA the reverse split is doing good. But For nitrous wouldnt a higher exhaust duration help to make sure you get every bit of nitrous out of hte cylinder creating the most power?

02sierraz71_5.3

iTrader: (2)

I completely agree with that statement but why does that mean you'd have less duration on the exhaust side, that statement doesnt preclude an exhaust bias. If the engine can take in a greater air charge on the intake then the exhaust can expell shouldnt you bias the exhaust?

Sport Side

iTrader: (6)

When the E/I percentage of the head is taken into account, an intake crutch can be used to flatten out the torque curve.

Example: 228/226-111 profile in a GTO

Sport Side

iTrader: (6)

Let me somewhat explain what I mean. Exhaust to Intake. Dividing your exhaust flow by your intake will give you a decimal answer, and therefore a percentage. The LS1/LS6/5.3L,6.0L heads average out well over 75%. The exhaust on these heads are very good. As the ratio gets higher, less exhaust lobe is needed to support the amount of charge being brought in by the intake side.

Using Richard @ WCCH's intake shootout, you can see that there is a heavy restriction on the intake side of things.

02sierraz71_5.3

iTrader: (2)

I understand what your saying that the average lsx head can flow 75% on the exhaust side vs the intake but its still relating less flow on the exhaust than the intake so what makes someone want to put more bias on the intake when it is allready flowing more than the exhaust.

For example the ls6 intake @.500 flows 245 then look at the set of heads to use say a set of AFR 205's@ .500 flow 281 on the intake and 221 on the exhaust. Even with the intake flowing less than the intake head runner its still more than the exhaust port on the head can let out. Then throw in another factor and thats a good overlap that is gonna create even more pull on the intake side, so Im looking at it like a properly specd setup the parts togethor are creating alot more pull towards the intake charge. Then on the exhaust side all we have to work with is header scavenging which I cant see creating anywhere near as close of a force on the exhaust pulse vs the intake considering overlap and the 25% greater efficency on the intake side.

BTW: I think the flow numbers everyone puts out at 28" are bullshit but its what we have to go on.

The only problem I have with the intake bias is that it seems to leave untapped power on the table in comparison to an exhaust bias. Im trying to find a dyno graph of the TR 227/224 vs the 224/227 to illustrate that the 224/227 would make more HP after 4500 resulting in better possible ET (even though I might have to eat crow )