Does anyone know what physical compression/temp/humidity 87, 89, or 91 octane detonates at? I don't need a static CR guess or DCR because those won't work and aren't accurate. I'm using Dynosim to figure out the actual compression I am getting so I can design my engine to get good fuel efficiency and high power.

I want to try and make a good engine with high compression, running on lower than usual octane and make good power that has decent gas mileage.

 

Can't help ya with the actual figures, however have you read EngineMasters ? The issue I'm refering to came out a few months back, was talking about pumpgas friendly engines.

 

Holy wack, just throw 91 in it and drive

So your saying that you want to build an engine just on the very edge of detonation?

Your screwed if you get some bad gas!

 

It's possible, however one has to do very detailed work, and even then I wouldn't do it without involving a water injection system. (although I'd use window washer instead)

 

Some one has already done it for ya. They are called
Diesel Engines.

 

lol, a diesel camaro...

I guess a guy could throw in an old 350 diesel

 

lmao..... that could actually be a halfway decent idea. And you thought the TPI's where torque-happy....

 

it's a little tough to build an engine that you have no idea what compression you are aiming for. I don't want to do this blind and with any luck, if I am right, I can find the best octane for performance and fuel efficiency. I was not planning to go right on the edge of detonation, but I did want to make it so you didn't have to mix grades of fuel for the best performance and I didn't want to go too high or low. I could just pick numbers out of thin air, but I don't like to do things half assed and if that's the way you do stuff fine.

BTW, hell no I'm not going diesel

 

Well ...

Smaller bore
Aluminum heads
Lower compression
Ceramic coated combustion chamber
Chambers smoothed out, no rough edges
Ceramic coated pistons
Water injection system


I couldn't find the issue I was talking about right now, so that's what I remember from the very long list.


As far as cranking it up some more, try maybe doing "Mr Peanut" style combustion chambers matched to piston tops

 

Do a search on "quench". I will be going to 10.8:1 on my next buildup. I will also be using 91 octane gasoline.

 

well I am probably building a 12 to 1 compression engine for my next one because I know what I am doing, but I need those invariables.

Lower compression??? you must be nuts

 

*looks down* Yup I got nuts



My list consisted of things one can do to avoid detonation, as we know lower compression is one of them, as is water injection etc etc

 

You cannot get an answer here because you're asking the wrong question. Dynamic compression is the closest you're going to get to a number, but you'll not be able to calculate actual cylinder pressure as this varies far too much with changing conditions... throttle position being only one of them.

Spark advance, loading, piston speeds and pressure wave effects are so tied in with cylinder pressure that you're simulator will not be able to show you a precise prediction.

There's only one way to find out and even then, knowing the actual pressure value isn't really going to help in the tuning process.

 

Dynamic compression is a highly unreliable number and I don't see how you can even begin to say it's better than the numbers I am getting from dynosim.

The curve they show is set to optimal spark advance for the RPM. WTF is so hard about computing a pistons speed? I mean there are even free sites that'll do it for you and they give the equation if you want! Dynosim has a variable max pressure per the intake CFM so yes you could at least see a rough estimate if not make a overestimated guess. It doesn't have to be precise, but it's a hell of a lot better than doing it blind. I bet the company that designed the intake knows when the pressure waves come into effect if at all. Without an open exhaust, power curves are going to be more accurate as well. Have you ever seen or heard how accurate this simulator is? obviously not and just so you know it's not that easy either.

bad news? You need to go back to school and figure out that these engines are not run by some unknown force we cannot comprehend. How are you going to talk down to me, you still have a 305.

 

1) 305 is in the logon name, doesn't mean for sure the person has a 305 or not, not that it would matter, some people don't mind keeping their 305's and just take them beyond what most consider the limit for the "worst engine ever"


2) Didn't know we had advanced engine mathematics as a subject in every school nowaday.


Why do we always have to argue and insult people here ?

 

Sorry, I was trying to help and/or save you some trouble.
Sounds like you don't need any help.

 

I just dont like negative nancy's coming in and telling me I'm wrong when they dont even know. It's not help when you basically said I don't know wtf I am doing. There was just no reason for that post. I just wanted to know one thing... Compressibility of octane rating...

 

there was a vette some time back running on biodiesel.
guy claimed to get around 300hp and around 450lbs/ft of torque out of it

 

let me ask you does this take into account the different burn rates you might see? you know the speed of combustion will change based upon load, combustion ratio which is easy to figure out, but then comes the interesting parts. combustion shape, quench squish, piston shape, port runner shape and induced turbulance, valve placement and size, as well as things like cam timing, avg piston speed (as you said) as well as peak piston speeds, piston dwell time and such. are you sure you can accuratly trust your dynosim to produce all those figures?

Quote:

Dynosim has a variable max pressure per the intake CFM so yes you could at least see a rough estimate if not make a overestimated guess. It doesn't have to be precise, but it's a hell of a lot better than doing it blind.

why are you sitting here telling us that dynamic compression ratio is unaccurate so it won't work but yet you will sit here and tell us even though the perssure per intake CFM isn't accurate but works good enough?

Quote:

I bet the company that designed the intake knows when the pressure waves come into effect if at all. Without an open exhaust, power curves are going to be more accurate as well.

the pressure waves can be changed a little bit based upon cam timing as well as exhuast legnth, port runner legnth in the head as well as design.
it's not as simple as you make it out to be

Quote:

Have you ever seen or heard how accurate this simulator is? obviously not and just so you know it's not that easy either.

I have never heard of a engine sim that is that accurate. since they never really take into account everything. they instead justp ull numbers out there bum for some things

Quote:

bad news? You need to go back to school and figure out that these engines are not run by some unknown force we cannot comprehend. How are you going to talk down to me, you still have a 305.

what does having a 305 have to do with if he can talk down to you. if he is trying to help you out in showing you that this dynosimulator might not be as good of help as you might expect then him driving a 305 is going to make his information invalid or unworthy?

I drive a honda accord. my other car is a mazda so whats that mean about me now?

 

the guy knows full well what he is talking about

the combustion of gasoline is giong to change on many variables here that your little simulator program isn't going to handle. if it did handle it chances are it is because it isn't a little simulator but rather a full on engineering product.

as the guy said finding out the combustion pressure isn't that easy. for pressure it takes into account most the things I stated plus the energy content in the gas (which you never asked) the a/f ratio humidity and many many other conditions that again I doubt your simulator is going to take into account.


your setting your hopes too high on this thing. simulators aren't perfect. they have flaws, and I doubt it really has provisions to put all the data in there you really would need to put in to get accurate information. sure it might be more accurate then desktop dyno but that doesn't mean much. sure a geo metro might beat a ford festiva. does that mean either one is still fast?
also as far as the accuracy of this program have you actually teted it? do you know for sure and can verify it's accuracy, or are you touting it's accuracy because it has more information and options avaliable then other programs? still dyou have have any proof of this?



I'm not trying to rain on your parade or put you down but rather show you that there might be more to see then just what you want to see.

 

Do you know how much faster 91 or 93 burns than 87? As long as you are not getting detonation it doesn’t really matter because I can reprogram the timing curve and yes I have the equipment to do just that. Ok I can’t simulate combustion shape, quench squish, piston shape, exact port runner shape or induced turbulence. Then again I have stock LT1 pistons which are what the simulator guesses I have, it does use one preset flame travel, but as far as I know it’s set high for performance engines. It has many different intake runner types for all kinds of airflow. I don’t believe the Stealth Ram intake I am getting is tuned, but I will check with Holley. If there is any intake turbulence I should find it when I do a head flow because I am going to port them myself and port match them with the intake to reduce turbulence. It doesn’t really matter where your valves are placed if you have the heads bench flowed and yes it does simulate valve size and you can even put in the inches of water used to get those numbers too for the simulation. They factor in piston length for accurate dwell time, it does cam timing, and peak piston speeds and also computes friction and pumping losses. YES, I have seen some simulations that carcraft did and I am confident that these numbers will be CLOSE to what I need.
It’s a hell of a lot more acurate than trying to use intake closure for the basis of your DCR than a full simulation. By rough guess I meant +/-20HP. In the tests that were run, I believe they were much closer than that.
That is if the intake even uses pressure waves and like I said, this simulator has a variety of intake airflows so I’m sure I could find one close.
You obviously don’t know much about this program then. Why not try the demo and find out for yourself. They also take into consideration exhaust type and if it’s open or uses a muffler. The company who made this program also makes another simulator called Dynomation which is supposed to be even more accurate because it does simulate almost everything, but it’s around $700.
Well to me this means he hasn’t really built any engines which means he is still new and making a statement like that is more of an insult than an opinion. By saying he needs to go back to school simply means he needs to read up more about what he is going to proclaim before he replies like that again to anyone.

Tells me you are confused because you are at a CHEVY CAMARO forum One of my co-workers has a honda and likes to talk s&*# about my camaro, but he stopped once it started breaking down on him.

 

One question: Since we aparently do not know the answers, why don't you go do your own research and come back and share your new found knowledge? You said you know what you are doing...

On a side note, why do I feel dumber for reading through this?

 

Now you are pulling statements from you’re a$$ because do you really know how much faster it burns changing octanes? How much hotter is it going to get with a lower octane? It’s going to change the top end of the power curve some and probably what RPM range you are getting max power at, but I doubt there’s going to be much more/less exhaust at the end of the exhaust stroke that would effect the intake numbers.

Fuel State Heat of Combustion Research Motor
MJ/kg Octane Octane
n-heptane l 44.592 0 0
n-heptane g 44.955
i-octane l 44.374 100 100
i-octane g 44.682
toluene l 40.554 124* (111) 112* (94)
toluene g 40.967
2-methylbutene-2 44.720 176* (113) 141* (81)

Energy Content Heat of Vaporisation Oxygen Content
Nett MJ/kg MJ/kg wt%
Methanol 19.95 1.154 49.9
Ethanol 26.68 0.913 34.7
MTBE 35.18 0.322 18.2
ETBE 36.29 0.310 15.7
TAME 36.28 0.323 15.7
Gasoline 42 - 44 0.297 0.0



As you can see, you obviously don’t know WTF you are talking about. Do you even know what R+M/2 is? Do you see the energy produced? Almost the same (0.5% difference for energy and less than that for heat). 87 octane means it has the compressibility of 87% iso-octane and 13% of n-heptane. Another know it all retard with a Honda, never fails. I put those other 2 types of fuel up for additional fuels people use or mix in for racing which I am not planning on using.

Again, it’s better than jumping into this blind and yes I do trust it. I’m not looking for a perfect Dynosim program, but this helps a lot. DYNOMATION, check it out. Relative to what? Where did speed or those 2 cars come into this? I did use it to build my last cam, but I have yet to dyno test it. You try and find one more accurate.

Go back to your Honda forums

 

http://chevyhiperformance.com/techarticles/94138/

 

You're starting to sound hostile now.
Maybe if you just restated your question you may get the help you're looking for.

I can tell you the reasons why some of use would never trust a simulator like you're talking about.

First it assumes that the programmer knows everything that happens within an engine.
Second it assumes that you will be feeding the program precise data. Garbage-in = garbage-out.
Third, a program with that many input variables brings with it a lot of error stacking which doesn't always average out to give the correct results.

Some of use wouldn't put our money on the results because of any one of these reasons.

Seems like you're trying to prove to us how much you already know, but so far I haven't seen anything that's truley tech here.

 

Hostile? I'm just upset because it was an easy question. If you don't know anything about the simulator and have no proof to back it up I just don't see how you can judge it. There are a lot of variables, but the ones that matter the most it takes into account for and a lot of the invariables it also uses. It took them many years to develop and test this program. It's been out since 2000 (as far as I know) so they've had plenty of time to tweak it and make it more accurate even though it is pretty much the same.



http://www.proracingsim.com/simtech.htm

 

Check this site out nonbelievers!

http://forums.corvetteforum.com/show...1257003&page=2

1% difference besides the 3000-3500 range in which he explains why the possible deviation!!!

I will see if I can find the article that carcraft or one of those magazines did and post it.

 

From what I have been told you cant run a 12 to 1 motor on 91 octane let alone 87

 

maybe it wont be 12:1, but I will try something over 11:1. Maybe it'll be over 12:1. All depends on what I find out

That's SCR though which means actual air can be way different based on the characteristics of your engine configuration.

 

Sorry I missed your post earlier, I must have missed it when responding to another post.

Only one answer, or 3 if you count each octane rating, I am looking for. That's what it looks like doesn't it. I just needed those compression numbers so I could have a set baseline for a number to shoot for. I've been searching, didn't see anything so I posted the question here. It'll be awhile before I can actually test it because I've got a lot more engine configurations to go through before I even think of build it.

Why would you feel dumber after reading through this?

 

You're not alone.

What was the saying, by the wise, yet aloof RB? Arguing on the internet is like the special olympics? Win or lose you're still retarded?

Aside from the hostility and arguing, the article from chevy hi perf looks like good info to me, thanks, i'll be reading that now..

 

valve placement does effect the burn rates as it effects the way the air goes into and out of the cylinder. not talking flow of the heads that is another story but rather the path the mixture takes upon entering anod how it mixes

piston length or rod length?

peak piston speeds aren't always going to mean much the piston takes various speeds through out the up and down motion


the whole intake closing I don't really buy that either cause there are more variables then that I would say so we agree

the intake ports whether exactly tuned or not are going to have pressure waves flowing through them.


desktop dyno even includes the type of exhuast. be it open or muffler, stepped headers and lets not get started at how inaccurate that program is



owning a 305 means you haven't built an engine?
shoot I guess I'm screwed all I own in an 80cid motor in my mazda and whatever 1.6L comes out to in my accord


and me owning a honda and the mazda mean I have been here a lot longer then you
the accord hasn't had too many problems other then the 3bbl car going out once one me (my fault kinda and led to me rebuilding the bitch.... need an adaptor plate I want to get my damn weber on there 3bbl carbs SUCK!!!!!!) oh and I had to adjust the valves. specs call for .006 when cold I had .025 on some of them. sounded like a diesel

 

r+M/2 is ron+mon/2 what is used in the states is either stated as that or can be even statd as PON. do you know what pon is?
it's two different types of rating octane.
I don't remember the specifics off hand but one if I remember right used a motor at around 1000rpms or something but ran really hot or smoething and the other was more of a higher speed rating again if I remember right.
in europe I know they don't use the ron+mon/2 they instead use just one of the ratings which partly accounts for their "higher" octane rating being it isn't the average of the two.


if 87 octane means it has the combustability of 87iso octane and13% heptane what happens when I throw 130 octane fuel in my car? 130% iso octane and -30% heptane? is that really feasably possible? which octane rating are you quoting also ron, mon, or pon? also are you meaning compressability or combustability? funny thing is for this guy who knows it all just out of curiosity did a google search myself and it uses the same exact words you used. why act smart when you have to use outside means? another guy in a chevy who thinks he knows it all. never fails

I admit I don't know how much faster it burns changing octane alone. but there are many other variables as well that are going to effect the speed the gasoline burns at other then octane. that is what the other guy was saying and I agree cause he is correct



as far as what those two cars have to do with anything.

they are both piles of crap but yeah one is better then the other.
might be the same situation here with desktop dyno and your dynosim.
by the way I just looked at it. you know what it reminds me of. desktop dyno. prolly uses the same exact engine
heck it is desktop dyno in a new package.
that sums that up for how accurate it is. desktop dyno can be way off.

since you said you sued it to simulate to help you build a cam
just wondering did you have it design your ramp profile?
I'm taking it no just your peak lift and your intake timing.
this is nothing more then desktop dyno
same tools same engine powering it with at best maybe some new tweaks.

I figuredy ou might of actually come on to something that might be better then desktop dyno but it doesn't look like it.
sure maybe better then nothing but by no means accurate


dynomation might be a little better from the looks of it from my very brief overview but I am goign to whithhold comment since I'm not sure.

I don't like the honda forums. they are a joke.
btw do you even know what type of honda I drive?
if you did maybe you would see part of the reason I don't go to the honda forums.

 

do a search for dynosim.
it looks like desktop dyno.


how accurate would you say desktop dyno is?

 

sounds like a bunch of marketing BS.

I've used desktop dyno and it's not very great.

think someone put together a stock L98 on there. it came up to have something like 380hp or so. for a stock L98? that's not too accurate.

I've tried to put together a few cars on their and the rated numbers more often then not are off by more then 50hp

this is not what you call accuracy.
it's what you call a rough tool to fool around and play with but by no means great.

real world learning and experience is much better then this "simulation" tool. if you want to talk simulation tool get something that is a true simulator not a toy.

 

thats nice. one example
some situations it might come up ok but most the time it doesn't come up very accurate.

 

and guys this is thirdgen.this is what we do. it's a sad part of life here but we argue and bicker like little kids.


part of it is when someone tries to help or correct he gets return fire from some kid who knows everything.

 

correct and combustion chamber shape makes a difference as well for fuel burn rates. I doubt it’s going to affect the intake cycle much if not at all. Maybe they take into consideration a mean or middle value for their calculations.

rod length, my bad. Piston height can be used to calculate SCR, but not used in the final calculations for the power curve because there are more variables like if it's domed and the shape, blah blah blah which just effects compression and turbulence right?

it’s takes into account the speed the pistons traveling throughout the RPM range along with the friction it creates and the losses due to that. There's no way to prove it doesn't use the variable piston speeds, but I do know I've seen sites that have a free calculator that will show you exactly that and explain the formula and make it sound easy so I would imagine they do take into consideration the speeds and expansion time of the fuel after ignition.

ty

correct me if I am wrong, but don’t the pressure waves have to comes from another cylinder’s closing intake aligned with another runner port to add more pressure to it? Their intakes do use basic wave pressures at certain RPM ranges.

Yes and it’s been many years since desktop dyno came out and they have refined it.

…

that’s good.

good. Yes MON uses 900 RPMs and a higher temp and RON uses 600 RPMs and a lower temp. I read that MON is better as an octane reference number if you can get that from a gas station because that’s a number more for racing engines. Yes I know about PON and those other 2 since I have been searching for the octane compressability.


like it shows on the table that didn’t come out very well, you can get 130% by using other types of fuel with a higher compression potential like toluene. Toluene has a RON octane rating of 121 and a MON rating of 107, leading to a (R+M)/2 rating of 114. If you wanted an octane rating of 110 [(R+M)/2] with 91 octane pump gas, you would have to mix 85% 114 and 15% 91.

yes there are, but to what extent do they effect the 4 strokes? I wonder what the simulator does or doesn’t take into consideration. I’ve seen 3 actual tests and every one of them has been almost dead on which means it has to be pretty accurate. They would have thrashed it in the magazine if it didn’t make close to the actual power numbers produced by the test engine. The +/- 20HP accuracy was a very pessimistic guess too. All I could really find about burn rates is that 87 burns faster than 93.

I don’t know what the difference is either, but like I said before, there is some pretty good proof that this one works. I need to see proof that it is inaccurate, not speculation. That’s what got me mad in the first place. You are assuming it is a bad program. Have you really tried it to its full potential with accurate flow numbers and configurations? Like I said before, it doesn’t have to be 100% dead on, but it sure helps with cam timing because you get to see what’s going with every event you change and make optimizations based on that.

no actually I called comp cams and manually entered in one of their recommended cams to find out their stock lift rates with 1.5 rockers were. It is 2.667. it varies with base cam lift and rocker ratio, but that is my baseline and I can find out what it’s going to be with 1.6 or 1.65 rockers too.

But where’s the proof? Do you know of anyone who had a bad experience with the newer program?

sounds good

I didn’t see your post # till after I made that other post so I take that back. You can stay here . Ok, you got me, what kind of Honda do you drive? Do they give misinformation like I see sometimes on the corvette forum?

looks can be deceiving. You or I would have to email the company to see if there are any changes and/or tweaks to the program to know for sure.

My friend used it and got high numbers for a 327 SBC and I took a look and what he used and he was using like wedge fully ported which was giving him higher than average numbers so I helped him to get a more accurate simulation. He never dynoed it so I can’t say if it was accurate or not.

with desktop dyno though right? Are you sure you had accurate numbers and didn’t choose one of the high performance heads? Are you sure the head flow numbers were right along with lift rates and valve timing? It looks the same, but there are added features to it since dyno2000 (I’m guessing desktop dyno was prior to that?) like open or muffler exhaust with small or large tube headers along with more selections for intake manifolds. Did you take into consideration ambient temp, engine temp, altitude, or humidity? They have simple formulas to compensate for those variables. I believe it says somewhere on the site for which conditions it’s calibrated for. Can you name a better simulator? Another company has one for $89, that’s a toy.

like I said before, that was one of 3 I’ve seen that were highly accurate. I’ll see if I can find more.

 

I'm getting too lazy to quote piece by piece anymore


but fuel burn rates can effect the exhuast gas velocity, volume and such this in turn effects the exhuast scaveging which effects the intake


with the whole rod legnth thing sure it might not make much of a difference but if you are going to tout a programs accuracy it should be able to account for everything like this and more then even what we brought up here. if it doesn't it's just guessing



with the piston speed being it's based on desktop dyno I doubt it takes that much into account.
does it even know your the weights of your rotating mass?




you don't need the pressure waves from another port to help create a pressure pulse. at times if using a specific harmonic you could have the intake runner creating it's own pressure pulses to hlp itself out. and with most intakes they at least try to make the runners the same legnth . they might not tune them to a specific rpm range though and instead tune it to it fits this way so this is how it goes (overly simplistic explanation but I'm sure you know what I mean) but it still will have it's rpm range it will work best with


I doubt they have refined it that much. it's still a fairly cheap tool compared to some of the others. maybe it's a little better but still not going to be *** and that trustworthy.



no your table didn't come out very well. shame on you.


as far as the magazines. they are a joke anymore.
they get paid to say half the stuff they do. if you get a wad of cash to say something even though you know it might not be true wouldn't you say it?

octane should effect burn rate by that much. most the octane is for is how well the fuel resist preignition or autocombustion rather.


I need sleep

as far as my honda it's a classic so to speak people on the honda forums don't even know about it and most ofthe people on the honda forums tell me my car doesn't either doesn't exist becuase an accord never came with a 1.6L. if your really bored one day look up an EF1 motor from honda.

never used high performance heads really except when fooling around or when using numbers from someone who had his heads flowed before putting the motor together. cam timing was always as was speced to me. if it was advanced or retarded I took that into account

desktop dyno (the original program) and dyno2000 both had open headers, large tube headers, stepped headers, mufflers and such. as far as the intake design I don't remember off hand but I now they had 2/4bbl carb, IR, tunnel ram, s/c, t/c, fuel injection and something else I think. I would have to bring it up and install it again to verify



I'll be around all day since this is all I do at work.

 

but you don’t even know if desktop dyno takes it into consideration. rotating mass just robs HP so it’s not critical for cam design.

Their user manual says ”in general, however, the trends and overall accuracy should be within 10%” for pressure waves even though I believe they do take them into consideration for their manifold types. It states mainly that high of a number for custom intakes. A dual plane intake manifold or a 4 cylinder intake would create a resonance effect, not a single plane (not one I could find). The length of the runner and size dictate what RPM range the wave pulses come into play and that’s why the TPI is so horrible for anything over 4000-5000 RPMs because the extremely long and small diameter runners create a negative effect at high RPMs, but helps at lower RPMs. It also has to be somewhat tuned to another runner because each reflection the pulse wave takes knocks down the effect dramatically. As you can see on the TPI, they are aimed at each other for better wave pressures. Cam timing events also effect the waves too, but like I said, the manifold has to take advantage of it and the user manual does state is uses some basic pressure wave tuning for a few different RPM ranges.

What others? You keep talking about them, but you need to post a link or something so I can see it. Dynomation is about the only other one and that’s made by the same company…

I tried to correct it, but the stupid forum won’t let me post it with more than one space between the separate rows. Here is the link if you want to check it out
http://www.faqs.org/faqs/autos/gasoline-faq/part1/

they get paid to show people that certain things either work or don’t work. I’ve seen magazines give bad reviews. Did you work for a magazine company or something? Where are you getting this info from?

someday I will, right now I’ve got a few engines to simulate

 

I've never seen an unbiased magazine article IMHO... usually they brag about how well one combo works, that, surprise surprise, has all parts from one company... weird eh?

I'd love to see a build using an edelbrock manifold, ported stock heads, lunati cam, eagle crank, etc.... totally mismatched brands....


and they tend to mis-compare, then brag about the power differences.... ie. comparing a ford 302 stroker build, with a giant mechanical roller cam, to a chev 350 build, with an "approximately equal cam", which happens to be a hydraulic flat tappet, with close advertised duration, and that's all.... results are totally out of whack....
anywho, that wasn't on topic...

 

rotating mass prolly won't have much to do with cam design.
but you know something that does? valve train mass. has a very big effect on cam as well as spring rates and damping.


with resonance. size doesn't have much of an effect on resoance but rather effects flow. chances in size though will make an effect.
the tuned to another runner is mainly just being the same legnth

a dual plane would work with resonance just like a single plane will. main difference is the single plane makes the intake work like 2 4 cylinders and a single plane will be more like a 8 cylinder.

if the manual says it takes advantage of it does it allow some pressure tuning does it allow you to specify runner legnth or is it just generic intake designs?.



the others? desktop dyno and dyno2000




its common knowledge with magz. they get paid for advertisement. giving a review gets them money if they do it favoribly. what better way to advertise your product then to give it to a magazine where people not only see your add but instead are able to sit there and read how good your product is by a magazine. and no I don't work for a magazine but I know of a few people who work in publishing of some sort or another.



too bad I can't get numbers from my honda to see how much power that things makes

 

Is it just possible.... That you are over-analyzing the problem?

I can't really see ANY simulator coming up with real-world accurate results with the kind of precision you are looking for. Most folks are of the opinion that an over 11:1 compression ratio is VERY hard to make streetable.... Especially on pump gas.

 

actually it’s not the valve train mass that effects the cam events, it’s the lifter type which this really doesn’t simulate. Some hydraulic lifters pump down and some pump up at high RPMs and Dynosim doesn’t take that into consideration, but I will still use it. The spring rates won’t make much difference because as one spring pushes up, another one is going down.

if it’s not made to effectively route the pressure wave to another runner, you will those that advantage and size matters all the more. Just look at the LS1 intake. They have those curves at the top of the intake to do just that and the short runners to make it use these waves to their best at higher frequencies. Mercedes has developed an intake with a variable runner so as you can see it matters.

No it won’t or at least not nearly as much because the cylinders will interrupt each other and cancel out the effect.

it had 3 single plane designs. Std, high, and max flow for the different types.

but those are made by the same company. You said there were better ones.

 

What i dont seem to understand is, if a person knows so much why would they come here to ask a question that they have repeatedly said is simple?

Just build the thing and see what happens.

 

valve train mass has a VERY big effect on how the valves and the cam work. floating valves, harmonic issues and so forth.
this weight only being held down by a spring has a specific resonant point and harmonics there of.



as long as the intake runner of one steady size it doesn't change the the resonant frequency. all the diamater of the runners would do is change the flow rate and velocity. mercades design I'm taking it is variable runner legnth. a lot of car makers do that. if it is variable runner size that is prolly for a different reason. that has to do not with pressure waves but velocity. larger runners don't have much velocity at lower rpms and smaller runners run out of steam at higher rpms. this isn't frequency related or related to the harmonics but just flow and velocity instead.



the problem with a single plane is all the pulses would be closer together time wise. to achieve the same rpm range use the pulses from another runner would require longer runners.
would work good though for high rpm designs which is what single planes are made for anyway.



that's a little better but still doesn't sound like it would be that



better ones as in enginering design programs designed for the engineer. best would be based upon a CAD design but that is more work then I think anyone would be willing to put into this. but the others would at least let you specify more options then just some generic ones mixed with with actual numbers.



this has been fun
sorry still at work and this has been making the day go by

 

too simple

didn't know you where still around either.
and with stu around as well
whats this world comming to

 

I moved to an area that didnt have High speed access, and basically my internet life ended for awhile. But, with the return of High speed comes the return to thirdgen. I've noticed that a lot of the old regulars arent around anymore.

 

I've noticed RB disappeared... anyone else?

 

a lot of people have come and gone.

holy crap though
just noticed that I have almost been here for 5 years now.....

I need help