Cam Design Pros Weigh In

Another shot at 6k just for comparison, the pressure lines have reversed during overlap so now the reversion will have stopped and it COULD be losing a bit of charge out the exhaust. I say could because remember it takes time for the charge to start moving. The graph at the bottom of this shot is the charge velocity, this was negative below 5k rpm but is now positive from the moment the intake opens even though the piston is still moving up. This happens because the exhaust is moving really fast out the exit which pulls on the intake to start intake charge moving..but it take time to move from the intake track, across the chamber and out the exhaust valve and the higher the RPM the less time it has, which is why higher reving engines want more cam duration. Below about 5k there is pressure in the exhaust and not enough velocity energy to be helpful so the overlap causes reversion when you thought you'd see charge loss. Its complicated.
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Interesting, thank you.

A buddy of mine wrote a software program which did all sorts of interesting calculations on HP and Torque back in the late 80's or early 90's as I recall. Let me look around on line and see if I can find a copy or whatever it may have turned into later on down the road. I remember it did some interesting math, but maybe not as complex as what you are using over there for $500.

I sort of think, no matter how much you spend on modeling software, it's gonna be hard to replace just having a dyno in your shop.

I'm currently working on a little Toyota 4 cylinder motor for my truck. Just a 22RE and maybe 140 HP total. I'm sitting here at my desk working on ceramic coating the pistons and combustion chambers right now actually. It would be interesting to run some analysis on that motor, especially in regard to thermal efficiency based on coating some or all of the chamber and part of the exhaust runners, etc. It has a cam (which I'm retarding 5 degrees) and a ported head, SS valves, etc.

I'm also working on another project (this one turbo charged) using a later series Toyota motor (the 3RZ-FE) which is used in drag racing and some off road motorsports applications. I actually have the short block sitting right next to my desk on a motor stand and plan to build a totally custom turbocharged setup for it. I know the stock block and forged crank can handle 1000 to 1200 HP without any modification (which seems nuts to me, but Toyota) - although for how long who knows. I'll only be running 15 PSI of boost as a daily driver for mine and *maybe* 20 LBS for racing. My HP target is 300 to 350 HP with a redline of perhaps 7500 or 8000 depending on the rods, pistons, etc, etc. It would be really interesting to have something to model that engine with regard to cylinder head flow, boost levels, camshaft lobe timing/profile, etc.

Anyway, thanks for the info. I'll check out the title you mentioned. I'll also see if I can dig up anything on that software my friend wrote back in the 80's and follow up here if I can find it.

Ray

 

Here is the software my friend Bryan wrote. It looks much, much more advanced these days. I don't know if he is still involved directly or not. I'm going to check it out further later, but here's the link I dug up just now. It looks interesting. Maybe you can let me know how it compares to what you are using, just by glancing over the website below?

https://speed-wiz.com/

 

There is no substitute for dyno data but its nice to start with parts and setting that will probably work out well...saves a lot of time and money.
Its the complete opposite approach.

Speed wiz is an empirical model that tries to add a bit or theory, DM is a theoretical approach that adds a bit or empirical data. There are some filling/emptying models that are kind of in between. Its also kind of easy of use...the tools like speed-wiz are generally very easy to setup and use, I used to use a similar one called Accelerator, super easy but would point in bad directions. DM has a F/E option build in and they sell it separate as DynoSim iirc., again much easier to use and the newest versions have a wave component so the decent.

When you go to a true wave model you need to answer a lot of questions before you get a result but they understand port taper and when more flow at the expense of velocity is bad. The wave models (like DM) are a bit like FEA of CFD for engines. I think Riccaro (sp? was the first and that had gotten to where it can pretty accurately output every the sound the engine will make with the air intake, mufflers and what not.....big bucks and OEMs love it, but that level is not needed for HP hunting.

This is what the setup for this threads engine looks like
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And here is what the wave result looks like next to the F/E result...the F/E model is making assumptions that the parts are well matched, the wave model is looking at the part you actually have kind of thing.
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Thank you for the run downt. That all looks pretty cool. I might have to contact the company and see how much the software is, etc. I gave up on Windows about 10 years ago and have only been using Unix and Mac since then. To run Windows software, usually I either have to drag out an old laptop or run some sort of emulation stuff on the iMac.

Based on the screen shot there, it looks like they cover quite a bit.

Do they have anything to account for the thermal impact of ceramic coated pistons / combustion chambers? I was also looking into maybe doing that dimple thing on the intake runners of my next motor. There's a company I follow on line which does it. I think it only improves flow a couple percent, but I'll take what I can get. Does the software have any way to take the base flow it computes and then add in some % multiplier or adjustment to its base line flow projections?

Definitely looks pretty cool.

Ray

 

yes, its on the screen shot for combustion right next to the compression ratio

I was also looking into maybe doing that dimple thing on the intake runners of my next motor. There's a company I follow on line which does it. I think it only improves flow a couple percent, but I'll take what I can get. Does the software have any way to take the base flow it computes and then add in some % multiplier or adjustment to its base line flow projections?

Definitely looks pretty cool.

Ray[/QUOTE]

The flow info comes from whatever you measure and input into the port flow table. There are example heads you can select as a starting point but garbage in/garbage out applies, you really want to use actual flow data. Ferrari heads are factory ported and very consistent so its easier enough to throw together a decent model for someone with the data I have. The same would apply to your dimpled ports...if the flow is better that should be reflected in the flow data and is what the software will use.

The cams are the same way, ideally you have a cam doctor file or similar. You can easily create an estimated profile from cam card info but is will never be quite right. Below is my engine with the estimated cam vs actual measured profile. The fake cam makes a little more hp for whatever reason so best to use the real file.
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There is a tool that will iterator cam timing. you set the bounties and tell it what better is exactly (hp or torque and at what rpms) and it will run simulations at every combination and save the top 10 for you. Then you can look for an off the shelf cam that is similar or as I did get something ground, but once you have the real cam you want to use that data to optimize the remaining items and get a good prediction. You can do the same with intake manifold type and dimensions as well as bore/stroke but I've personally never really found a use for those options. You can spend a lot of time on headers...they are pretty important so its generally worth the effort to look at a few design options, which sends you back to cams and intake tuning so it takes a while, I easily spent 100 hours on my engine where literally everything was being modified in some way so everything had to be a variable in the simulations and still I'd do a few things a little different if I were doing it over today.
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Thank very much, again, for the great run down.

I've been busy over here ceramic coating pistons and making a YouTube video about it. I'm just taking a break while the video renders. I haven't had a chance to zoom in and look at the multiple screen shots you posted (although I did get as far as saving them all to my desktop), but I will soon.

I'm starting to think I might want to invest in this software. I did locate a YouTube video by the company and will be watching that shortly here. In the near future, I'm planning on building that turbocharged Toyota 3RZ motor and I was going to fabricate the turbo manifold as well as the intake manifold myself. So the part you mentioned about modeling the intake sounds interesting. Being able to compute the cam specs as you outlined also sounds real handy.

Ray

 

Software can reduce mistakes and point to where improvements are possible.

Looking at the weird exhaust cam timing that appears to work it looks like the combination of 70s/80s ferrari heads having too much exhaust flow relative to I take flow and big cams that want to rev well above where the headers and intake are tuned so shifting the exhaust pulse timing moves more air without restricting the exhaust to where it hurts... I guess.....but for sure when you see something like that helping you know for sure something else is buggered up a bit and fixing it will make everything better.

 

I did a little playing just because so here is the base engine, cams at 102-110 no boost but I optimized the headers and there is more on top and the midrange is much better.
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Then new setup with new headers vs old with the odd cam timing with the blower back on but I still lose on peak hp. That's what the software does.
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so new header plus change the drive ratio from 1.5 to 1.6 to match the peak and its better everywhere

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If you're in the mood to model engines.. I could send you the specs on my Toyota 22RE motor and exhaust, etc. I'd be curious to see what you come up with.

Here's a video I just posted about ceramic coating my pistons... if you jump to around 22:00 minutes in the video, I show some of the stuff I was messing around with as far as adjusting my camshaft timing. I sure would be interested to see what your modeling software has to say about my motor and cam timing and/or just any comments you might have after watching the video and seeing the Intake and exhaust valve events.



I'm running a mild ported head on this motor and a few flow exhaust. I don't know if I can find the exact CFM of the cylinder head or not, but I might be able to call the company who does the port work. Having your own flow bench sure would be nice

Ray

 

I have a flow bench, SuperFlow 600 with Flowcom data logger. If you decide to flow test something, let me know.

 

Thanks Wade, appreciate that!

Ray

 

For anyone interested in this thread (now or in the future), here are two videos from the company that makes the Engine simulation software in question here. Even just watching how they run through everything in the videos is pretty interesting:



I'm watching this one right now:

 

I have an 88 Pickup with that engine. I've often thought about pulling mine out and dropping it into a dumpster to make room for something else.

 

Mine is a 1990.

The 22RE motor isn't exactly a technological marvel of achievement, but it's damn hard to kill. Down the road, I'm going to replace mine with a turbo charged 3RZ-FE motor out of the 1st gen Tacoma.

Ray

 

Where is FerrariPilot? He has done a lot of work on this with the early 308s, there are many threads. He recommended Catcams to me years ago. They have an aggressive street grind for 308. John, where are you?

 

It is a constant battle. I will advise clients that the cover are completely "glued" with sealer and that will require additional time to remove as I don't do it that way and will not leave any behind to find its way into the oil pick up screen. You can't imagine some of the engines I have seen. I had a TR that had both cover packed with silicone, black on one side and red on the other. I mean, if you pay for the whole tube, might as well use it all right?

 

Nothing really to add here really. Who reground your cams? I know of a few good cam grinders with lots of masters. I'm sort of surprised so few in the Ferrari world experiment with this, but I get it. It's a deep rabbit hole.

Be sure to replace the o-rings on the splined distributor shafts with correct size. Just had a car that I did with a seal kit and the o-ring size was wrong leading to distributor leaking like crazy.

 

2v carbureted Ferrari engines like a tight LSA, 100-104. With mild or moderate performance cams I like the intake around 102-104. P6 racing cams I had set at 98 intake, but those are a disaster with anything but very very high compression (12:1+).

 

Those look fantastic. Nice job.

Our local Ferrari place has a vapor blaster recently also. There's no media in the process correct? It's just water or CO2 or something?

Ray