Here's the components:

1997 L31 Vortec long block. Stock rods and pistons. Block decked, pistons 0.025" in the hole.
Fel-Pro 0.015" shim head gaskets.
Vortec heads. Screw in studs, 1.60 exhaust valves.
Comp Nitrous HP 276/288 cam.
PAC beehive springs. 130lb seat pressure.
Scorpion 1.5 roller rockers.
FIRST fuel injection manifold
Dyno Don headers, y-pipe, and full exhaust.

Here's the chassis dyno:






Here's the question - what does the crowd think I would pickup with some AFR 195's?

GD

 

I have no clue, but I'll bet that's fun to drive.

 

Immediate first reaction was

And then when the brakes were wholly inadequate to haul it down from the surprising velocity it achieved.

And then of course it rained immediately following the dyno session so it was something like

GD

 

Cool setup man and nice numbers, I bet its night and day from what you had before.

Mike

 

Great setup! I wouldn't do anything but put gas in it

 

That's about 375 at the flywheel. Looks like it's running really well.

 

What was the peak HP RPM? I see 1.6 exhaust valves. Any other work done to the heads? Very similar to my last Vortec build that put the 3700 lbs solidly into the 12's at 108+. I did run a 1.6 rocker on the XR276HR.
I can run a Torque Master program to see how the AFRs compare but I'd need what your current peak intake port CFM is. AFR lists theirs at 280 CFM @ .550" +/- (IIRC). I'm going to guess and say the gains down low would be minimal but the better breathing should push power past peak some. And of course they would provide room for more cam (nitrous notwithstanding).
EDIT: Torque Master isn't going to provide any graphs but it will give an indication of where peak HP RPM might be based on port flow and the cam it suggests. It also guesses at HP and TQ numbers.

 

Interesting! The peak HP is at 5,110 RPM

The Vortec heads were not ported or modified in any way other than increasing the exhaust valve size from 1.5 to 1.6 on the recommendation of my head guy. That's also why I used the split duration cam - 288 on the exhaust side - crutches for the Vortec exhaust port.

GD

 

That was the thinking behind the 276/282 split I ran.
​​​​​​I would have thought the peak RPM would have been higher but 224@.050" isn't exactly a monster.
I can say the heads will support more as they are. That's to say, more cam and I'd be inclined to go that way rather than heads. But let it be clear before I go up in flames here and that I'm fully aware of the superiority of the AFR heads compared to the Vortecs (Excuse me if I sound like I'm on the defensive but I had this conversation the other day and was beat up pretty bad!).
Let's see what TM has to say on a cam choice for the Vortecs compared to the AFRs. And vice-versa if I can work it in reverse.
But my two cents now is to drive it! If it's anything like mine was, it'll be a ton of fun. I loved steering with the rear tires!

 

Quick question: What did you calculate your CR to be?
With flat tops and .025" down I think I was right at 10:1.
The L31 piston is dished isn't it?

 

It was stock Vortec minus the HG thickness removed by using the .015 shim gaskets. I wanted the quench right at .040

I estimated the compression would be about 9.8 IIRC. I elected to leave the dished pistons and the slightly lower compression in case of accidental ProCharger installation.

GD

 

I like that one.

 

Well, you know the floor could be slippery while you are walking by with a complete procharger setup. These things happen.

 

So, messing around with Torque Master and as I've learned it's not conducive to manipulating input data.
There are a few criteria: As it's a cam selection program (and only that) it'll work off of peak port CFM or peak HP RPM or a HP target. It works very well when you already have a set of heads and a target CR.
Case in point: Vortecs with a best guess 210 CFM at max lift and 10:1 CR gets the output shown below. Note the peak HP RPM. Look familiar? A check out the recommended cam. Duration is spot on woth yours on the intake and I the overlap (given the suggested LSA of 107) is also a direct hit with the 276/288. That would explain the peak HP RPM similarity. 5140.



Now, if I bump the port flow to 220...



RPM peak goes up with the overlap.
Now the problem is that if I use the peak CFM of the AFR heads at 280, the CR at 10:1 doesn't cut it as the cam selection goes off the charts. Note the RPM.



Push the CR up to 11.5...


Now it's starting to look like an AFR headed 11:1 CR 350. We've got an almost copy of this in the "fleet" however the cam has been dialed back. Consequently we're also not utilizing the full capability of the heads. Shift RPM is 6500 rather than the nearly 7000 the heads can support.
So, I think the point here is, while the AFR are probably one of the best out of the box heads you can buy, you have to go a long way to build a complete package.
Personally, I'd target a < 6000 RPM redline and use the Vortecs to their limit. That is depending on what it is you want to do Mr accidentally installing a Procharger....

 

That program makes no sense what so ever. It makes no sense that 10:1 and 11.5:1 would be that much different in cam and power and rpm. You dont neeed 11:1 to use 195 heads on a 355

 

I've chatted with Vizard about this and the objective of the program is very clear. Select a cam for the best torque. Not the other way around. And I stated that in my opening line in the last post. As explained to me, if you haven't got enough compression, then you better fill the cylinder for all it's worth. But because the program is very specific, the results don't make sense as you say. And vice-versa. But look at the projected output at 10:1. 558 HP but you gotta go to 8 grand to see it. Dial up the compression and it looks as you might expect. 290 duration and less than 7k.
The only reason the program doesn't make sense is because the inputs are terribly mismatched. Plain and simple.
Now here's one for you. Why would you use an AFR 195 on a pedestrian build? If you have 280 CFM of port capacity, why use 220? Only because you can I suppose but from a build logic point of view, it's wasteful. That's all I'm saying.

EDIT: Just to clarify. The non-sensible part is because the target entered into the program is the 280 CFM peak flow. That was the input parameter. Of course you can put an AFR 195 on a 10:1 350. But don't expect to use 280 CFM. Select a different parameter such as peak HP RPM and it will determine minimum CFM required or target HP and it'll determine CFM and RPM, (and I'm open to your suggestions), but as it's laid out in the screenshot, CFM was selected and the AFR max was used. Pretty simple really.

 

that would never happen. 558 might be possible at 10:1 but it wouldnt likely happen with 195 cc even if it did flow280. Because flow isn’t everything if the velocity and area aren’t optimized. Flow doesn’t dictate peak rpm range necessarily esp on a 23 deg sbc head

if that program was worthwhile for max torque, why wouldn’t you run 15:1 or high comp? Whats it say for cam then?

i get it, its a very limited program designed around a set of parameters. A combo of specific parts for a street engine i suppose. I get it theres a more optimal cam for a given comp but the fact remains comp and cam ratios together don’t necessarily mean much. If you ever seen cam only ls or lt cars, for a set stock head and compression ratios, the bigger cams always make more and more power vs small cams. Everything just moves up in rpm til the head limits the combo. Same concept as superstockers in a sense.

 

Am I missing something? The only change you made from the first chart to the second was Required Min CFM Head Port Flow from 210 to 220 and the DCR changed .3 lower, the Idle Vacuum dropped a full 2 inches, and the Cranking Pressure dropped by 10 psi. This program sure looks flawed to me.
Target Intake Port CC's is not even in the ballpark. 158cc is Gen 1 smogger head territory. The Intake Port Induction number (11.5) must be incorrect.

 

The only change I made was to up the port flow. The program made a significant change in the cam spec. The 158cc demonstrates that for the peak port CFM spec'd, that all the volume you need. This keeps port velocity up and that's what produces torque. Velocity equals cylinder filling. Take a 220cc port and see what kind of energy there is at a measly 220 CFM. It would be very lazy. And a poor performer wouldn't you agree?
And the intake tract doesn't enter into the cam spec in this program. It's there to show where the intake tract would produce peak torque. Then you would alter the intake length to coincide with the peak HP rpm. Get the cam spec. Check the peak HP RPM point and go from there.
I think the issue here is that you all are looking at it as a dyno simulation. Which it is not. It's a cam spec program. Big difference.
The program is very simple. I'm not here to sell it. I just use to spec a cam for a given list of parts. If you've got a crappy mismatched list, you'll get something seemingly unreasonable from it.

 

Very interesting. I understand what the software is doing - it's essentially saying "use this cam" to maximize the flow capabilities of the head given the specs entered for chosen head flow.

That is crazy that it picks basically the same cam I came up with from hours of playing around on various software packages (not that one though!) and internet research, etc. I chose the nitrous cam with the larger exhaust duration to match up with a pro-charger at around 10-12 psi. Should be pretty ridiculous with 10 psi. The exhaust duration should really help with the clearing the cylinders and pulling in more charge.

Given a "typical" drivetrain loss of 18% with the 700R4, 10" 3000 converter..... that puts me around 396 crank HP. Not far off from the theoretical 408 crank HP.

Really enlightening - thanks Skinny!

GD

 

I don't see how any of this is helpful to GD. Number one, the intake tract length you used is WAY off for his build. Number two, why would you select Street/Strip to assist with GD's question. It looks like the program's definition for it's "street/strip" selection would be more a race car that you could drive on the street. Number three, there's nothing about exhaust systems unless there are assumptions built into the different performance categories. It's nothing more than pure coincidence that the cam it selected using Street/Strip had similar seat duration with such differences in the intake tract length you entered and the calculated 107 lobe spread vs his actual 113.

You asked, "Why would you use an AFR 195 on a pedestrian build?" Because high flow, high velocity heads like the AFRs you can run a MUCH smaller cam and make more torque and horsepower and pull more vacuum (better manners) than you can running a lesser set of heads with a larger cam. You can also run a lot less gear and stall speed and run as good or better ETs with a high efficiency and flow head/small cam combo than you can with a low flow head/big cam combo. GM's been going down that road for a number of years with the LS engines.

 

PRECISELY!

 

While its the intent, there is some odd logic in it that can get ppl confused. Like a 10:1 using a 315 duration cam and trying to rev to 8100 lol. If you don’t understand what the program is doing it will mislead you easily. I know its not a dyno program but it seems to correlate peak hp rpm with flow numbers only and is extremely compression ratio sensitive when thats not 100% the story. I’m sure its trying to calculate flow area somehow but it just seems funky to me. I like controlled inductions software better. And engine analyzer pro for the dyno portion

 

Let's see if I can't calm the waters a little.
It's helpful to GD because he appreciates the input.
1) The intake tract length doesn't enter into the cam selection process. It's there as side bar and allows the user to choose a length. By the way, do you know long how the intake tract length is on a SBC with his intake?
2) The street/strip selection helps to eliminate the nasty program pop ups that occur when you enter parameters that are outside of the norm such as an AFR heads and too low a CR. They include warnings such as too low and idle vacuum, too high or too low a DCR or an peak RPM that's unrealistic.There's another output that can be selected for all out racing. This dampens those popups. Much like street/strip as compared to the street selection. It's a work around.
3). This all about torque production. The premise is that you have optimal exhaust. As in a properly tuned open header or exhaust system that behaves nearly that way.
4) There is no coincidence. Torque Master (and Vizard) cam selection does not put the emphasis on duration. Rather it goes straight for overlap and LSA. And the LSA is based on a 23 degree SBC head, intake valve size with 10.5:1 CR and the CID it supplies. The duration is the result of that. GDs engine performs as well as it does because his overlap is in the ballpark. I'll bet you that if GD chose a tighter LSA with the same overlap, his torque output will go up.

Now about your "high flow, high velocity heads like the AFRs" comment. High flow? Undeniably. High velocity? I'll ask a question. At 220 CFM ( yes that's a small number like the Vortec peak flow) which head do you think will have the greatest port energy? At a 1.7 CSA vs a 1.9 CSA at 220 CFM, it's going to be smaller head. This is why the Vortec is so good at what it does. I'm not going to argue about the relative merits of each because those are well known. I'm not going to put a Vortec on a 400 CID nor would I put a 195 head on a 305. The point here, at the limits of the smaller head, it'll do better job than the larger given a properly spec'd cam.
And what the vehicle is used in for doesn't make a pinch of difference in the TM program. It's all about selecting a cam for maximum torque. What you do with it is up to you. Maybe you don't want max TQ but would rather have less output spread out over a broader RPM range. Then choose a cam that does that. But you won't find that here. It's about max peak output.
Plain and simple.

 

The program is based on a 23 degree SBC with an average discharge coefficient (based on valve size) and 10.5:1 CR.
Using your example, " a 10:1 using a 315 duration cam and trying to rev to 8100 ", if you only have 210 CFM available, how else are you going to achieve maximum output? Rev the living snot out of it is how. Is it practical? Hardly. That's where the confusion lies. It won't accept a mismatched pile of parts.
If you'd like, I can run the program with whatever combination of bits you have in mind. I can select peak HP RPM rather than port CFM and it'll output the minimum port to get the job done. Remember too that it will achieve the port CFM with the smallest port volume possible.
I like dyno software too. If the situation was a little different at this end, I'd get the controlled induction program we'd discussed before. But what I'd do is put together my preferred pile of parts, select a cam using TM, then run the simulation.
I've a question for you. Which head would you select for best torque output on a 350 that might see 5300 RPM tops? I'd say the smaller head would have greater port energy at low RPM and build greater torque as a result.

 

There is nothing mismatched about an afr 195 on a 355 with 10:1 comp

problem is what is best torque? Best torque where? 2000 rpm? 4000 rpm? 5000 rpm? I can put it anywhere just about woth a 5300 rpm limit just by changing cam and intake runner length

in a street strip world nobody should care about low rpm torque because everyone should have atleast 3000 rpm stall speed or else you are doing it wrong imo. Nobody should ever be going wot under 3000 rpm. Even tpi cars will downshift a gear, and 2400-2800 stall works great for them. I’d still take a 180-195 afr head over stock vortec if im looking for max power and torque. the flow is there, cam appropriately and it will show up

 

Perhaps mismatched is a poor choice of words. The point here is are you going to utilize the AFRs on a 10:1 350 to there fullest? The answer is no. You'll never consume 280 CFM of port capacity. That's all I'm saying. You could easily get more torque output out of smaller head. Provided it's a decent head.
AFR 180. 240 CFM at .400"
AFR 195. 247 at .400"
Which head will have the greatest port energy at .400"?
This is why I get comments like "I'm building a truck engine" when I have plans to put my RHS 175cc heads on a 383. Everyone knows it'll be a torque monster.

 

Man, there is just enough truth/facts mixed in all this misinformation/misunderstanding that someone that didn't know any better might believe it all. I think you have just enough real wold, hands on experience to be dangerous with a piece of simulation software that I don't believe is being applied appropriately. I'm going to take a few and see if I just want to leave this one alone or if I think i can address it without sounding like a *****.

 

As you stated, it is limited. Those limits have been described.
Max CR I can use is 13.5:1. I chose 8000 RPM as the peak HP limit.
The airflow required is far and away greater than the AFRs can provide.

 

im not so much concerned about the head flow but the induction system flow from intake to valve. A poor intake will kill head flow too. A bad combustion chamber can hurt performance despite good flow. Alot of variables to consider. You most certainly could utilize that flow on a 10:1 ratio. Low compression does not mean you cant make power and rpm. I can make it go to 6500 and make power, going to 12:1 may only raise the curve numbers a few %. But the curve shape will be there. I believe nascar short track engines were 9:1 and still made well over 700 hp from 358 inches. The 12:1 ratio versions made mid high 800’s

 

Think what you want.
Describe any single bit of misinformation in my post. Read carefully. Don't misconstrue what the results are or how the program works for anything other than what they are.
Have you used the program before? No. Do you even know what the program is? No. Do you understand how I'm relating the results? No. Do you understand what the results mean? No.
I'm not trying to sound like a ***** either. I'm just relating the facts as they're presented.
And for the record, you'd better be sure what it is I'm doing here. I haven't spec'd a cam as in saying use this. I haven't selected a cylinder head. I'm inputting values and posting the results. How you interpret them is up to you.

 

and there lies the problem, leaving it up to others to decipher whats goin on. You’d be better off making a conclusion and presenting it

but for the subject of this thread, more head will make more power on that car. Port the vortecs or go aftermarket

 

Let's keep it in the context of the program. Venture outside of that and all bets are off.
But I can't see where you could spec a cam within reason on a 10:1 350 and use all of that port flow without building something unreasonable. There's going to have to be a lot of RPM involved.

 

I posted the results. Now here we are.

 

yes it will require rpm. But i dont believe you will automatically utilize more cfm at less rpm just by bumping compression up. I dont think more compression will automatically allow you to rpm higher

 

Thinking in terms of cam selection, higher compression warrants more cam doesn't it? That's kind of the point in raising compression in the first place. You don't have to. But you should. And more cam equals higher peaks.

 

It's interesting to look back on my thread from over a year ago when I was speculating about the performance:

https://www.thirdgen.org/forums/diy-...anagement.html

I'm very pleased with the results. Owning the DynoJet and seeing plenty of customer-built engines that fail to meet their expectations is proof that this isn't as easy as many people think it is.

GD

 

Well no, you cam as needed to fit your rpm goal and fill your cylinders. Raise compression only if your fuel can tolerate it. 91-93 oct pump gas most sbc guys wont be over 11:1 static comp. cylinder pressure is too high, theres too much heat in the cyl and it will detonate. E85 or 112+ oct, run 13:1-14:1 just fine. Cyl pressure is up, you extract more energy from the amount of fuel and air you compress, but the act alone i dont feel changes how the induction system behaves. I dont think cam has to be tied into compression. Big cams are for more rpm and cyl fill at those rpms. Theres always a trade off, high overlap will not fill cyl at low rpm. Bottom end is reduced, which generally is only a street car concern. To make up for it you do tend to run more compression. You get your rpms and make more power every where because the thermal efficiency goes up.

If you wanted a 6000 rpm peak 355, the cam is the same whether its 9:1 or 12:1. Its just that 12:1 makes alot more power provided both are on same fuel that is not detonation limited

 

Let's see if I can't calm the waters a little.
It's helpful to GD because he appreciates the input.
Maybe so but it relates very little to anything about his build.

1) The intake tract length doesn't enter into the cam selection process. It's there as side bar and allows the user to choose a length.
Think about this - If it doesn’t have anything to do with cam selection why is it there for the user to enter? If it doesn't effect anything it should, lol.

By the way, do you know long how the intake tract length is on a SBC with his intake?
Yes I do. The FIRST manifold tract length is 16.2” by the measured and calculated mid-point of runner. I haven’t measured the Vortec head length but most intake runners for SBC heads measure right at 5”. That would yield a total intake tract length of 21.2”. However, I’ve found that to get EA simulation software to mimic the actual dyno curve results the shortest “straight-line” measurement works best – it’s 14.25" or total intake tract length of 19.25" including the heads.

2) The street/strip selection helps to eliminate the nasty program pop ups that occur when you enter parameters that are outside of the norm such as an AFR heads and too low a CR. They include warnings such as too low and idle vacuum, too high or too low a DCR or an peak RPM that's unrealistic. There's another output that can be selected for all out racing. This dampens those popups. Much like street/strip as compared to the street selection. It's a work around.
So you’re saying it gives the same results whether you select street or race and the pop ups just warns you that the cam it calculates is very limited in its application?

3). This all about torque production. The premise is that you have optimal exhaust. As in a properly tuned open header or exhaust system that behaves nearly that way.
Based on this, then not only would you have to have a premier “zero loss” flowing exhaust, you would have to pick and be able to install the proper diameter and length headers in the car to match the cam. Does it give you any idea what that all that would be for the headers? I can tell you all that matters regarding the application and how well that cam will work with “it”.

4) There is no coincidence. Torque Master (and Vizard) cam selection does not put the emphasis on duration. Rather it goes straight for overlap and LSA. And the LSA is based on a 23 degree SBC head, intake valve size with 10.5:1 CR and the CID it supplies. The duration is the result of that. GDs engine performs as well as it does because his overlap is in the ballpark.
His runner length is around 20” and his lobe spread is 113 degrees.You entered an intake tract length of 11.5”.Would that be a 6.5” runner dual plane or 6.5” runner single plane or is that another “perfect assumption” of the program?The application suggested a cam with ballpark duration as his, but it is on a 107 degree spread. Overlap of his is 56 degrees vs the program’s 64 might be ballpark but the power curves on those two cams would be a good bit different - assuming everything else the same including the intake tract length.

I'll bet you that if GD chose a tighter LSA with the same overlap, his torque output will go up.
Within reason, probably so. My cam of choice will always be the one with the highest rate of rise, tightest lobe spread, and least duration/overlap as possible to get the most power under the curve for a particular application and desired vacuum. However things may vary significantly depending on the application.

Now about your "high flow, high velocity heads like the AFRs" comment. High flow? Undeniably. High velocity? I'll ask a question. At 220 CFM ( yes that's a small number like the Vortec peak flow) which head do you think will have the greatest port energy? At a 1.7 CSA vs a 1.9 CSA at 220 CFM, it's going to be smaller head.
Yes - Smaller port, same flow, greater efficiency/port energy

What about a small port flowing less air to a larger port flowing more air?
Vortec given 220cfm and 1.7csa ---- 220cfm/1.7csa = 129.4cfm/csa

AFR 195 Street given 280cfm and 1.905csa ---- 280/1.905 = 147.0cfm/csa
Comparing the AFR flow at .500” (cam lift) – 275cfm/1.905csa = 144.4 cfm/csa

147.0 and 144.4 is greater than 129.4. There’s so much more to it than just this one number, but yes the Street AFR 195 is a higher flowing and consider it a more efficient/higher velocity head in comparison to the stock Vortec.

I'm not going to argue about the relative merits of each because those are well known. I'm not going to put a Vortec on a 400 CID
Depending on the desired budget, goals, and application I would.The Vortecs are one of the best bang for the buck heads available and make excellent power (within reason) on a 400.The ones you have are REALLY nice with stellar flow numbers and should work extremely well on your combination.

nor would I put a 195 head on a 305.
Have to agree with you there.

The point here, at the limits of the smaller head, it'll do better job than the larger given a properly spec'd cam.
That’s an opinion you have drawn regarding the output from this program. In general, on a 10:1, 355 you can run less overlap, stall speed, and gearing going with the 195AFRs and it will run circles around a set of 220cfm Vortecs no matter what cam you run.

And what the vehicle is used in for doesn't make a pinch of difference in the TM program. It's all about selecting a cam for maximum torque. What you do with it is up to you. Maybe you don't want max TQ but would rather have less output spread out over a broader RPM range. Then choose a cam that does that. But you won't find that here. It's about max peak output. Plain and simple.
So unless GD is willing to change just about everything about his car/application, remind me how this was helpful to him?

Think what you want.
I will.

Describe any single bit of misinformation in my post.
I did

Read carefully.
Thanks for the warning, I did

Don't misconstrue what the results are or how the program works for anything other than what they are.
I get it, but it seems out of place in this thread to me – opinions may vary

Have you used the program before? No. Do you even know what the program is? No. Do you understand how I'm relating the results? No. Do you understand what the results mean? No.
I have a better understanding of the program now but still don’t see how any much if any of it relates to GD’s post.

I'm not trying to sound like a ***** either.
OK

I'm just relating the facts as they're presented
Facts? Are you sure about that? See above comments.

And for the record, you'd better be sure what it is I'm doing here.
Thanks again for the warning. For the record, I don’t believe anyone can be sure of what you’re doing within this post?

I haven't spec'd a cam as in saying use this.
OK

I haven't selected a cylinder head.
GD asked what we thought he would pick up with some AFR 195's

The comments you’ve made (see your statement in bold above) seems to me you believe the AFRs would be a waste based on the information you provided. If you stated that as an opinion and didn’t try to justify it with a very limited program that doesn’t seem to be able to relate to his application all would be well.

I'm inputting values and posting the results.
You might want to get those right by changing the intake tract length and bump the wave reflection down to the 3rd wave while you're there and see what happens.

How you interpret them is up to you.
I’m good, just for some reason I’m worried about others trying to interpret them.

 

A fair bit. Probably near 30-40whp with the 180's. You'd still gain power with the 195's no doubt. If you were taking the engine higher, above 6000rpm, then yeah I'd say 195's all the way.

Its hard to tell because your graph isn't showing RPM. However, assuming the TQ and HP are still crossing at 5250rpm, your peak power is under 5000rpm and its already falling off. If you are looking at brand name, I'd say AFR 180s. You aren't going to be spinning this thing to 7k.

To make use of the 195's you need to spin the engine past 6000. I don't see that happening with a First intake. Why I chose the 195's is particularly because I wanted to focus power in the 5000-7000rpm range. I didn't much care about below that. While I've never dyno'd my GTA, I have looked at the data logs. I'm not making peak torque till over 5000rpm, and peak power is somewhere around 6700rpm. It makes good torque from about 4000rpm upwards. But really isn't much fun below 4000rpm. And its really NOT fun at all below 3000rpm, a stock L98 would out-run it.

I also bought a larger head because I was considering a 383 or 396 in the future and wanted enough head to feed it without taking a loss on selling 180's to buy 195's later.

 

So it appears (to me) that Vizard's TM program would work best for dyno shootouts where the goal is Max Torque.
The program does not account for any vehicle, it's weight, gearing, type of transmission, how open or restrictive the exhaust system is - nothing.
Just the best cam to produce max torque given a relatively narrow set of parameters.

 

Port flow velocity. And your CFM you are stating is ??? Next thought is what are you building? AFR 195's have been a proven street head for 20+ years, will out perform Vortecs all day, every day, from just about any RPM range down low , especially as you wind it up.

 

I think what he's saying is say you have 14:1, be tough to turn the engine over with a peanut cam, so you have to have enough cam to bleed the pressure off to crank it.

 

For ***** and giggles if you plug the numbers into good old Desktop Dyno it spits out 443lb-ft @ 4000rpm, and 402hp @ 5500rpm. DesktopDyno doesn't account for accessories, so its like running an engine with nothing attached so its numbers are always really high. So throw in a 20% driveline loss and you get some numbers and a graph that looks pretty similar to GD's actual Dyno. I also threw the AFR 195's at it too for comparison. Small loss below 3500rpm, and big gains up top.


I have flow files for Vortec, and all the AFR heads already saved, so it was easy to 'build' a Vortec TPI engine.

But its Desktop Dyno, you gotta take anything it spits out with a giant salt block.

 

I didn't realize what a shitstorm this would cause and GD has been gracious enough to let his thread go beyond what was probably the original intent. And for the record GD and I have had a couple of PM's regarding Torque Master (TM) and how it stacks up against his real world results. The results are interesting.

I didn't write the program. It was developed by David Vizard and Stan Weiss (if you don't know who they are, look them up). I use it for educational purposes. Otherwise I'm calling Mike Jones and asking for a cam spec (if you don't know who he his, look him up).

These are the operating principles as far as I know.
First off, the part of TM I'm using is directed at a typical Gen 1 SBC with 23 heads. Keep that in mind. People have been firing back back with Pro Stock engines, DOHC engines, lawn mower engines, etc. It's none of those.
I'm also generally in the hydraulic roller selectable screen. There are options for other lifters as well.

From my conversations with Stan Weiss it's built around the premise of an optimal LSA for a given CID. This is important. A 350 SBC with 10.5:1 CR and a intake valve Discharge Coefficient (DC) that would result from an average 2.02" valve seat gets an LSA of 108. If you don't like that approach, contact Vizard. I can PM you his e-mail. He's typically very responsive (although lately he's kind of been under the radar and I don't think his health is the best).
Other things to take into consideration are: CR is limited to max of 13.5:1. If you want to run 15:1, forget about it here. Maximum engine speed is 8000 RPM.
The DC of the intake valve has an impact as well. Better CDs will yield different results. Same as CR. Change any of those and TM follows suit. Case in point. A Vortec head with a 1.94" intake valve DC will have a lower value than an AFR head with a 2.05 intake valve. Further to that. the minimum port flow value required for greatest output will determine the minimum port volume needed to get there. If you've got crappy heads, don't blame TM. If it says for 210 CFM would need a minimum 158cc port, then that's what it says. If you flow only 210 with your 180cc head, then that's something to take into consideration. This also an important detail in that maximum TQ output is achieved with the highest port energy. TM is saying lazy heads don't build torque.
Anything you see in yellow is calculated by TM. Anything in white is a data entry point. Data is selectable for either minimum port flow required (use this if you have heads and know that value) or Peak Power RPM (use this if you have a target) or Estimated HP (use this if you have a target). So when you're looking at the screen, keep that in mind. Yellow and white boxes will change colour to reflect what input has been selected.
There are also options for applications. That said, it doesn't change the spec (in as far as I've seen anyway). What it does do, after calculating a spec, is to direct your attention to the failings of that calculation based on your input. Example being, if street is selected and your combination of inputs results in manifold vacuum being too low or the dynamic compression being too high or too low, it will send a pop-up screen so you can address this. Your 12.5:1 SBC might not work so well on pump gas. You'll be advised to lower the CR. Conversely, you can then select Street Strip or Race and go from there.
Lastly there's an induction length entry box. This isn't used in the cam selection per se. The 11.5" length seen is a default value. There's also an indication of where peak HP and TQ would occur based on that length. Now, it's up to you to examine where the cam selected makes peak HP and decide whether you want to change the induction to better coincide with the peak HP RPM value. Or select your specific induction length and change some other parts of your combination to dial the two in (induction peak RPMs and cam peak HP RPM). My assumption here (MY assumption) is that if your inputs crank out a cam spec that has peak HP RPM at 6000, you can adjust the induction length to match that if you wish. Or vice versa.

I'm probably missing out on a few things but perhaps that will answer some of the questions.

Now, this is the kicker. It is not application specific.
It's about selecting a cam based on what your inputs are and the cam selection is directed at maximum output.
Think of it as a dyno mule where the objective is to get the greatest torque output possible. In racing terms it's described as a "glory run". What you do with that result is up to you.
If you have any complaints, talk to the developer. I'm only the messenger. And it would seem at times not a very good one.

 

GD.
PM sent.

 

I tried to come off the least negative and combative as I could in my last post. However, after rereading it I can see where it could have easily been taken that way - especially using the line by line response method. At the time I felt you deserved it and asked for it. I'm usually pretty laid back, especially on forums where at times something innocent enough can get blown out of proportion or taken out of context. I think that's what I did and would like to apologize to you and GD for not handling it in an appropriate manner - as I feel you have done above.

I'm glad you know about Mike Jones and utilize him for cam recommendations - he will not steer you wrong.

 

That reply sir is appreciated.
An interesting side note to a correspondence I've had with Mike. I asked for an recommendation for a proposed 383. He offered "x" based on his experience and how he felt the engine would be utilized and on my submitted form to him.
Excellent.
Then I asked that if he'd consider another recommendation. One that was directed more towards WOT output only (I'd take care of chassis, gearing and converter to match). His recommendation came around to more closely matching the TM result I was seeing.
Interesting.
Anyway, thanks again for your reply.

 

Well I know I'm late to the party here but from what I can see on the dyno graphs is the power curve is nearly flat once the rpm/motor is "up on the cam". It would be nice to read the RPM on the curve for comparison but the point where the lines cross tells me that's 5252rpm so the engine kept pulling much higher RPM than that. So with an automatic trans you won't have to shift much and the shift points should be fairly high.

So as far as the AFR 195 heads go they would tilt the curve up at the higher rpm end and would need a cam with more lift to raise the entire power curve. But after all that work I think you should drive it and enjoy it before making changes and by then you should know more what you want to do. You might decide for an entire new short block with better pistons and cam to match the AFR heads. But motor should be a fun drive as it is now.

 

Is this a 350 355 or 383 what cam specs? Ours is a 383 stroker, 9.8 compression,113 heads they flow 250 cfm, LPE219 cam by lingenfelter with 1.6 roller rockers, first performance intake with the bigger TB 76mm 36 lb injectors, Holley dual sync distributor and a Holley hp efi system controlling it.. wonder what HP we can expect? Love to know what cam your using