mrr23,
if the exhaust of a Dodge ram can be flowed, I sure fixturing can be modified to do an LS1.
To all: I not interested in any pi$$ing match on what is best, what solves all. Most have a "camp" they want to support and that great. I have posted some things I have found over the years that I know work. The main thing I try to get across is a what works for someone may not be ideal for what you have, thats all.

Chris

 

all cams come in a box. these aren't box cams. all these cams are from countless hours of R&D from all these companies that know more about cams and motors than we do.

i proved that going to more duration over exhaust brings the power band higher in the rpms. i even did it with the VHP 047 cam using DD2003. stop. read, ingest, learn. you keep saying a reverse split cam is needed for us intake restricted LS motors. and everything here proves me right. the intake just isn't that restrictive as people think they are. unless you want to spin the motor way beyond the intakes capabilities.

 

ok! you win, geez




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i'll clarify one last thing.

Sorry, I am relating "box cams" to "off the shelf cams". Both the same to me.
See, one setup to the other may seem sooo close, but yet they are more than likely not when you bring in the complete details. Thats why I'm not a big fan off "off the shelf cams". Not one cam, will fit everyones needs. I understand that Vinci has tons of R&D, but that was my only point.

Good discussion guys

 

it's not a pi$$ing match. when you read sportside 5.3 posts, he keeps insisting the LS intakes are so restrictive that a reverse split cam is needed. read the comp 216/220 thread and you'll see this. hell, the dyno sheet from patrick g shows this to be false. until you try to beyond it's capabilites. the reverse split did nothing to help power until 5500 rpms.

 

i'll look at this in a positive way. without knowing what a reverse split power is below 3000 rpms, it's a good cam with minimal low end loss (3000 rpm to 5000 rpm) with the option for more power above 6000 if you want to spin it that high. good thing about my 2000 formula. i can lock it in 2nd gear with the shifter and do runs starting from 5 mph. i've done it. i should scan and post it.

 

seeing as that dyno sheet is from converter.cc, all of the dyno sheets from there testing the converters were done by VHP for Yank. they did the runs in 3rd gear from 0 mph. they used a breakout box doing it. look at those and you can see what kind of power their SS made. http://www.converter.cc/dyno_shop.htm

 

Same power and torque to 5000 (no loss)

Same driveability at all rpm (no loss)

35-60 more rwhp in the upper ranges (huge gain).

For my LS1 project car #3 (I'm on 5 now), it was the IDEAL cam. That doesn't mean it would be ideal for others in this day and age. Remember, there have been lots of advances in reducing intake flow restrictions. 2-3 years ago, crutching the intake with more duration made more power everywhere. The fact that mine picked up in the upper ranges proved to be an even bigger bonus for me!

 

Actually, you're somewhat mistaken. All of the dyno shop sheets for Yank were conducted at VHP, that's true. But in 2001, I bought the car from Mike at Yank and put in a new motor. The dyno sheets posted were conducted at Hennessey Motorsports (yes, the Viper guys) in Houston. Same car, different motor, different dynos (but we're splitting hairs).

I have been the webmaster for Yank for years. I just posted dynos on their sight to make it easy to post here.

 

i've been assisting vinci with his website also. name at bottom of main page. i just happen to notice the converter.cc in the link. and was just using it to show people there is a way to show dyno runs all the way through the rpms is all. you still have it?

 

all in all, you can read all the posts in the world. see different results for different cams in different vehicles. sometimes same cam in different vehicles. you'll see different results all the time. in the end, all you can do is call the manufacturers and take what you've read and take a stab at what you feel is the cam for you. you might get it right the first time. you may not. there are many others here that have been through more than one cam.

sometimes too much information can cloud the mind.

 

The LS series motor is intake restricted and if you speak to people who understand what race motors are you would understand that. I'm not here to start a peeing match, but Desktop dyno is a long way from a SuperFlow and even farther from the real world.

Chris and other folks who design motors for a living don't bet the farm on DD2003. To base any performance claims, trends, or claim absolutes on design on the results of a software package without real world empirical data to verify those results I feel is wrong on many accounts.

Here are several points from the Cam Thread which address some of the points made thus far.

Stock Intake to exhaust ratio is ~70-75% before the exhaust is bolted on.... the intake will definately restrict the heads. So, figure about 80% ratio is what you'll end up with. Due to runner length and the current lack of cost effective shorter runner intakes, the LS1 is limited to a 4800rpm torque peak.... thus 6200-6400rpm HP peak (due to the wave of the incoming intake aircharge as it bonces between the closed intake valve open air plenum).

When I do a cam for a setup like this, I go for max cylinder pressure under 6200rpm.

The area most cam companies error on is the exhaust. This causes problems with these limited intake designs. The exhaust VE's are the most important on these setups.

Simply put, on an N/A motor the intake aircharge is not assisted. (leaving wave dynamics of the aircharge out for a moment).

After the combustion stroke there is tremendous pressure in the cylinder. As soon as the exhaust valve cracks open it flows a LOT of air. It's basically boosted out of the cylinder if you want to look at it like this. Having the exhaust valve open too early not only costs heat (power) velocity through the exhaust runners, it also empties the cylinder before the intake valve is open enough to take advantage of the pressure differential. (in a limited overlap/smogable camshaft this is especially true) This causes exhaust reversion and is one of the key factors in surging problems.

By the airflow reversing course it is loosing a lot of it's inertia. Typically this is overcome before peak torque however. So only low-speed issues are present. At the track these motors are always above 4500rpm so this does not affect track times too much.

Stilll....there is significant power lost by allowing reversion. So it makes sense to open the exhaust valve a little later and increase the overlap a bit. By adding advance into the camshaft this makes the problem even worse as now you're opening the exhaust a few more degrees earlier.....and shortening the effectiveness of the intake unless you have significant overlap flow to over come this.

Simply put, advancing a cam makes it more exhaust bias relative to TDC. Retarding a cam makes it more intake bias relative to TDC.




Now, I'm not saying a reverse split is always best. I'm not saying a symetrical is always best, and I'm not saying a standard split is best. I don't think Chris is either.

What is being said is that your motor is an airpump. Once you understand ALL the factors that affect that airpump you can optimize that airpump for maximum pumping efficency. In effect, many of these cams specified will work but you may be leaving a bunch of power on the table.

Let me cite an example.

I've seen three of Chris' grinds one was for combo X, and the other was for combo Y, and the final one was for combo Z.

Without getting into the specifics one was a reverse split, the other was darn near symetrical, and the last one was a positive split. Does that mean Chris is in all threee camps. Nope, Chris isn't in a camp except the proper camshaft design camp, which is where a lot of other folks need to be. He designs cams based on a motors needs, and the duration, split, LSA, etc... are byproducts.

 

After reading j-rods post. It seems to me, companies that sell camshafts with large standard splits and an advance ground in are really working against themselves to fit an intake restricted motor.

You already have a camshaft that is exhaust bias'd. Advancing it, is only making it worse, is it not?

Just a question. Dont jump me standard splitters.

 

I agree, that is why my custom cam for my forged 347 is close reverse, a little more intake lift, a 110 lsa but straight up (No advance)

 

lets look a little farther out of the box. most here are quoting what happens in RACE motors. and i have said after looking at the dynos, a reverse split seems to work better in a RACE application. but what about street applications? dynos aren't showing what is happening below 3000 rpms. i know patrick said he had no difference in driveability using the reverse split. but what about people with a heavier vehicle, stock converter, and mild gearing? they aren't going to be able to use that gain over 5500 rpms. they are looking for a cam that will produce more torque than horsepower. and in their usable range. that was my point in all this discussion. you guys are pointing out the benefits of a RACE application. i'm pointing out the benefits in other situations. (and yes i've read where all of you keep saying it might not be best for everyone)

ad as far as DD2003 goes, i don't live and die by it. i already said that. i said it does pretty good at showing a pattern of what's going to happen. and it hink it did a pretty good showing of it. matched pretty much the dyno of patrick's. a little loss under 5000 rpm. then starts gaining after 5500.

 

222/224 is not a reverse split cam.

That is a standard split or traditional split cam.

 

mrr23,
Combination. Period. Whether it be for something to get grocerys in or something that needs to haul 3500# down the track under 10 seconds. Combination, Combination.
As far as reverse splits goes vs everything else. . .lets back up a little to the basics. We all agree an engine is an air pump. The CORRECT cam doesn't care about what name you label it, it cares about getting the right amount of air in and out to accomplish a power goal at a pre determined rpm band. With that said, I feel that is why some OEM's, Honda and Misubishi, use reverse split camshafts in production cars because it is the most effiecent way to get air in and out to make power.

So I disagree with you that reverse splits are drag only. They are like anything. . .if they are the best choice to do a job, that is the part to use. Again I am not pro anything, I try to make people think.

Chris

 

Yes Mrr23. And I think thats why Mr. Straub made a good point by giving an example of this nature: his camshafts may start out as a traditional split at a given lift, but might be a reverse at another.

So, the way that you are ( oh geez-->)stereotyping all camshafts that have a reverse split at a given lift are for race motors, is incorrect. They are giving examples of how it may change at different segments, meeting the standards set by the cylinder head.

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OOOOOPS. I'm to late. Chris just posted

 

and how you are (oh geez -->) stereotyping the LS1 intake as being such a restriction over in the comp 216/220 thread is incorrect as well. even in the dyno above, the intake didn't become a restriction until 5500 rpms. so all your posting of the intake as being a restriction is seriously pointing the truck people in the wrong direction. so far the only results i've seen any benefit of having a reverse split cam is if you want to turn past 5500 rpms? i can only draw the conclusions i have with the evidence presented in front of me.

edit: yes between him and me it's a pissing contest.

 

i agree. it's all in the combination. and that's why i got into this thread. because of another member telling the truck people the LS1 intake is so restrictive. and that's why they need a reverse split cam. i've even posted CHP test of all the LS series of manifolds. the truck manifold does better than my LS1 manifold!!!! in all tests they performed, the truck manifold does better than the LS1 manifold. so, i felt a need to make him justify why it's so restrictive. and he hasn't it's taken others to try and help him justify it. are you getting my point yet? i've gotten yours.

 

yes.

Chris