Paul F

iTrader: (2)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by J-Rod:
<strong>But why on the ASA cam and the Grand Am cam which are race only camshafts, and in fact on all their LSx series cams whether or not it was full exhaust, open header, or whatever did GM use a standard split?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I can agree with you on that for sure, but we were not designing a "road or circle track cam". I'm sure when GM was R&Ding those cams no one came up and asked, "how's the low end going to be" or "how's that thing going to drive around in a parking lot", or better yet "is it going to die on me at stop lights". I know I get asked those questions on a daily basis. Those were also things that we had in mind when designing these cams. Those guys only care about a very narrow powerband. Our job is much harder since we are after good power everywhere. If we are going dyno racing then that's fine but if we are after a very balanced driver that a whole different story.

Each cam has it place and I think most could agree on that, but for someone to say "reverse split cams are useless or a gimick" is just ...... Well you get my point.

Paul

JF WS6

The reverse splits may be in NA 346 cars that are running very quick right now (my car included), but they aren't putting out the most power.

In the case of H/C cars, look at the evidence. First example already spoken of is the GM Grand Am cam that is capable of 470+RWHP, then there's Cartek's latest offering of the X package which is alleged to have made 470+ on 2 different vehicles so far and then you have the LG G5X-2 that has put out about 460+. The first Cartek X package cars were making 450+ as well. Point is, these are ALL traditional split cams.

I have not heard of a hydraulic reverse split ever making power over 445RWHP on a stock short block.

The current NA record holder for a 346 may be running a reverse split, but it is NOT a hydraulic cam, it's a solid roller, so I don't see how that relates to a discussion of other hydraulic cams.

Paul F

iTrader: (2)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by JF WS6:
<strong> The reverse splits may be in NA 346 cars that are running very quick right now (my car included), but they aren't putting out the most power.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Who ever claimed they were?? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">The current NA record holder for a 346 may be running a reverse split, but it is NOT a hydraulic cam, it's a solid roller, so I don't see how that relates to a discussion of other hydraulic cams. </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I'm sorry I keep rereading the topic but I can't find the word hydraulic anywhere. Maybe your eyes are better then mine. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />


Paul

HP-GURU

X 2 C, I think you mean PSI and not CFM.

Y2K2LS1

Id like to see HP/TQ graphs of all the popular tuner shop cams with #'s from 3500rpms to 6250 in 250 rpm increments. Thats where I spend most of my time at, not a huge convertor 1/4 only car that needs a powerband from 5500-6500.

IMO midrange is just as (if not more) important than top end. Area under the curve!! Is there not a computer program that can give area under the curve of a dyno graph in some sort of square units? That would really show what is making power, and not peaky #'s.

<img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Got Me SOM

iTrader: (2)

I'll take a graph with more area under the curve over a peaky hp curve anyday..

for most of us that drive our mules everday that's where we spend most of our time, in the midrange. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

so many good tuners with great head/cam packages, who do you go with? seems like everybody makes great power nowadays.

Who should I go with? my goal is to do low (11.40 or better) in a full weight minus spare tire and lightweight wheels 02 SS A4.

Any suggestions? Just sold my house today so I have a little extra cash! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

jmX

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Y2K2LS1:
<strong> Area under the curve!! Is there not a computer program that can give area under the curve of a dyno graph in some sort of square units? That would really show what is making power, and not peaky #'s.

<img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Area under the curve you encounter while racing is whats important. Extra power down low will be nice for daily driving but in a race it may not matter much.

And as for area under the curve, you need to define a standard RPM range to judge all curves at, say, the top 2500rpm (be it 4500 to 7000 or 4300 to 6800, etc). Once you do that, take 10 sample points across that range, use trapazoidal estimation, and figure out the area under the curve. The unit of measurement will be made up, but you'll get a number that will allow you to compare area under the curve. I used to calculate area under the curve for lots of peoples dyno graphs, but it really isnt something you can compare for cams since a) everybody is on a different dyno, b) everybody has different exhaust setups, and c) head and tuning differences play a big part in it.

I coded a quick web-app that'll give you a number for the RPM range of 4100 to 6600 (standard for heads/cam pacakges) so you can see how your power you'll use when racing compares as you change your setup (assuming you have various dyno graphs to enter into the calculator).

You can try it here. I can expand the RPM range as well so its 2k to 6600, which might show you how much headers actually help (big broad gains!).
http://www.ls1howto.com/calculators/hparea.php

LOnSLO

iTrader: (15)

Let's take this scenario, since I've been pondering on it for a few days. I'm currently running a reverse split 230/226 which I'm pretty happy with. It made just over 400 with stock heads. Now I have s2 5.3L heads. Power is now in the 43X range. For arguments sake, what would happen if I change it to a 230/232? I know drivability would decrease, but from a power and scavenging aspect, what are the opinions on what would happen here?

J-Rod

I'd like to thank the guys from TR for making a lot of good points and providing a lot of good information. I'd also like to thank jmX for his graphing tool, and say thanks to everyone who has participated in this thread with useful information or a generally positive post. I think the folks at TR have explained why they are doing things the way they are. As I said, their cams do make good power I don't want anyone to construe anything otherwise.

I applaud them on their choice of building a dyno mule. I think that is apositive step in the right direction. We can speculate all we want and do modeling on Performance Trends, Engine Analyzer Pro (aero-thermal) modeling software. and/or anything else we want to.

But, actually putting it on the dyno, and then running it down the track is far better than a milion threads that we post in with a bunch of opinions.

So, I for one look forward to your upcoming dyno program.

As a side note, I will point out that last year Roger Ramjet was working on an "ideal" stock replacement cam for the Z06 using AEPro. Here is what he found, and it was a reverse split....(See, I'm not totally biased). But, he needed a bunch more data for his model, so there is some question about the validity of his model. But I thought I would post it as food for thought...


http://www.z06vette.com/forums/showt...&threadid=8525

I’ve been thinking again (Sometimes I sits and thinks – sometimes I just sits). I have suggested that I think substantial gains are in a cam change. Too bad the cam is so difficult to get out of these machines.

The ground rules:
Use Performance Trends, Engine Analyzer Pro (aero-thermal) modeling software.
Use LS6-01 valve and spring data to allow all LS6 motors to use the same cam.
Retain stock ratio rockers.
’01 pup cats must go.
Baseline performance is ’02 cam 204/211 degree I/E duration on 116 degree lobe separation, installed 4 degrees retard (events: IO –18, IC 42, EO 37.5, EC –6.5). Valve lift is .551 for I and .547 for E.
Attempt to gain HP above 4500 RPM because that is the after shift condition.

<img src="http://www.z06vette.com/images/public/ls6%20idl%20cam.jpg" alt=" - " />

Results:
Interestingly, the only timing event that had any significant affect on produced power was IO. Advancing the IO event all the way to 10 degrees takes advantage of inertia charging. The specs for the first try cam are: 232/211 degree I/E duration on 109 degree lobe separation, installed 3 degrees advance (events: IO 10, IC 42, EO 37.5, EC –6.5). Intake and exhaust lift were held to .525 inch. Notice the HP loss in the low-mid area. That should make launches easier. The ’01 injectors will handle the fuel flow but the ’02 will not (duty cycle ~ 89%). The valve open overlap dwell is increased by 28 degrees to 63 degrees. This cam will have a serious rump rump but be streetable.

I am not comfortable with the model definition that I currently have for the LS6. I will rerun the model when better data is available. Andrews has ground custom cams for me before. They have a direct digital grinder. I would expect the cost to be around $500. The blank to do this grind is not out of the ordinary.

JF WS6

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Paul @ Thunder:
<strong> Who ever claimed they were?? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

I'm sorry I keep rereading the topic but I can't find the word hydraulic anywhere. Maybe your eyes are better then mine. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />


Paul </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Ok Paul, no need to get uppity. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> I wasn't trying to **** anyone off.

I was just trying to say that standard splits seem to make the most power, and the reason why I brought up the deal between hydraulic and solid roller is that you said the fastest NA 346 was a reverse split.

The only point I was trying to make is that if Jason ran a standard split cam in that car (increasing the exhaust duration while leaving the intake the same) with his solid roller I bet he'd be even faster and put down more power.

Idle characteristics and driveability wouldn't be as much of an issue for a car like that I would think.

Constrictor 98TA

If it makes any difference, I am still planning on the TR227/224 cam for my swap. I have an appointment at Speed Inc on Friday May 23rd for a dynotune. Several MFBA members will be at my house on Wednesday the 21st to witness the "resurrection" of Constrictor.

At that time, I will have a nice set of Stage 2 heads, LS6 intake, Hooker LTs, ASP pulley, and all the other boltons...

I would love to be a test mule and swap in a bunch of different cams to see how they all react, but I just dont have the money to do it, so once my setup is done, I hope to be yet another A4er with 400+ RWHP through a reverse split and will have comments on daily driver quality.

Thanks for all the great info in this thread.

Y2K2LS1

JMX, that calulator is neat, i'm going to play around with it a bit, thanx. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

6800 is a little to crazy for me, on a stock bottom. I know it can probably handle it but for peace of mind I wouldnt shift (m6) anywhere past 64-6500. Alot of my races on the street begin in the 3500 rpm range so power down at least that far is important to me. If i were comparing cams though, 4000-6500rpms would be what I compare.

<img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Steve - Race Eng

iTrader: (1)

The main reason for reducing exhaust duration (good flowing exhaust system with headers) is to increase mid range torque. This is especially true when running a wide LSA (lobe seperation angle) 112 and above. As LSA is increased the exhaust valve opens sooner during the power stroke, all else remaining the same. Advancing the cam to close the intake valve sooner gets the exhaust valve opening sooner yet. Less work is done on the piston with cylinder pressure being bled off sooner.

The way around this is to lessen the exhaust duration thus opening the exhaust valve later so the cylinder pressure works on the piston for a longer time during the power stroke.
An added plus is less reversion. One respondent had it correct when he mentioned the intake manifold restriction. Restriction on the intake side whether by intake or small throttle body, carb. causes excessive intake manifold vacuum at wide open throttle. During the overlap stroke there is a good chance of exhaust gas getting back up into the intake manifold if intake manifold pressure is less than exhaust system pressure (always true in a street engine). Cutting back exhaust timing will reduce overlap thereby reducing the reverse flow (reversion).
Although the engine may produce slightly less top end power the increase in mid range power will more than make up for the slight decrease for normal street use. In fact I use reduced exhaust duration on most of my competition engines that have good flowing exhaust ports.

J-Rod

Thanks for the info Steve. Do you have any recommendations based upon your experience.

Robs98Z28

I would like to state that this has been one of the best threads I've read on this site. its incredibly interesting and I have learned alot from it.

Ok, now my question. For the person (I dont remember who it was) that brought up the solid lifter cam point, How does having a solid lifter change things? I would think all the same principles apply. But I dont know how to account for the bleeding lifters. There would have to be a differential equation of some sort to factor that in.

And one other thing I'm curious about. A couple of months ago I had the oppertunity to install a specially made sheetmetal intake manifold on a car at kooks headers. This manifold had very short intake runners. How would an intake like this effect the powerband as opposed to an Ls1 or ls6 intake.

Now, from what I understand so far the record for max cam power is a solid lifter with a reverse split (I would assume using a ls6 intake). If the person with this cam was to run a sold lifter with a regular split do you guys think he would make more?

I'm dont mean to defer the discussion in this thread from hydraulic to solid lifters but when I read this stuff I dont always understand exactly whats going on, and I'd like to find out. Thats what the site is here for right?

Anyway thanks to anyone who can offer me any insight.

Rob

mike#9

iTrader: (3)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by HP-GURU:
<strong> I guess I was trying to say in short that the biased intake lobe has a lot more to do than head and intake flows.

Also I hope that the porters do so with the intake manifold in mind. The entry of the port should match the exit of the manifold, and not just the height and width. This should form a continous cross section. The angle of the runner should not change at the head and manifold interface, worst case of this was the old Torker carb intakes, a 45 angle would be formed at the head and intake interface.

It is possible to take a head that flows 330 and an intake that flows 280, and have this combination flow less than a head that flows 270 and an intake that flows 280.

They are a system. I'm definately not a know it all, but I love reading about high power N/A setups.

The LS1 combinations are putting out some serious power.

I think if someone tightens down the LSA's some, run the tuned length headers, perhaps a solid cam, we will see 500rwhp before 6500 on a 346.

LSA needs to be tightened down so the intake can work in the range where it boosts power. Seems to do this very well up to 6000 rpm, so we need to build alot of TQ before 6000 and hold onto it.

Think the big strokers can benefit from tightening down the LSA so they don't fight against the manifold as much, plus the exhaust system will be allowed to help out a little more. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">HP-GURU.. it seems to me that you are knowledgeable with this topic. What headers out there are tune length.

Because I can't decifer the post all that well. What is the best cam for a basic everyday setup like mine.

Also will probably have stage 2 heads done, but cam for now.

Reverse split, standard split, equal duration??

mike#9

iTrader: (3)

More stupid questions... but this is the only way that I will learn.

What does LSA stand for.

What do you mean by tightening down on the LSA's. What exactly is a solid cam, roller cam, hydrualic etc.

Sorry if I sound dumb. I know a lot of everyday/intemediate type things, but this technical stuff I am still trying to get down

Steve98TransAm

iTrader: (1)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by mike#9:
<strong> More stupid questions... but this is the only way that I will learn.

What does LSA stand for.

What do you mean by tightening down on the LSA's. What exactly is a solid cam, roller cam, hydrualic etc.

Sorry if I sound dumb. I know a lot of everyday/intemediate type things, but this technical stuff I am still trying to get down </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">LSA = Lobe Separation Angle - this is the difference (in degrees) between the intake and exhaust valve events.

mike#9

iTrader: (3)

Thanks a lot

mike#9

iTrader: (3)

Thanks a lot

What is ASA?