the maximum cfm that can be attained depends on the total package.

talking about the maximum cfm of a bore and stroke at a given RPM without taking into consideration anything else is pointless. an engine doesn't run by holding a piston in your hand and swinging it around in the air at 4000 RPM (if you could).

i don't need to reread your question because I know exactly what you are asking and it is not an intelligent question. what i don't know is why you are asking it. if you dont know the answer, there are an unlimited amount of calculators available online. if you do know the answer then that's good for you but there is nothing you can do with it. characteristics of airflow just do not work that way.

How long is a piece of string?

 

Why can’t you discuss anything without being abrasive, your history on the forum in setting yourself up as this knower of all and how dare anyone ask anything or disagree. I asked you a simple question to establish limits of airflow from zero to maximum. Knowing that resultant curve allows one to extrapolate various inlet conditions. This isn’t for me or you but it might lend to thought from some of the others on here. You want to ridicule me and challenge my capabilities so be it, you want to debate credentials bring it on. Personally I’m not in the mood or have the time to play your play in the dirt game. I’m not an auto mechanic, gave that up 30 years ago just like to drive great cars now and pay people like you to fix them and wash them. I’m not going to fall into your trivial mind trap like I said I don’t have the time or interest in debating anything with you.

 

your history with me dictates my tone with you.

basically, don't talk to me. I am under no obligation to converse with you and you are free to block me from your view. I don't set myself up as anything, I answer questions I know the answer to and read about the ones I don't.....so given the percentage of threads I participate in, I know a lot less than you seem to want to imply I think I do.

I don't treat everyone like this, just you and one or two others. if you think I am an auto mechanic, then that's great. it means you have some respect for my expertise. I mean, this is a tech section on a car forum, what would you rather discuss? foreign policy? macroeconomics? I'd LOVE to talk physics with you.

or don't talk to me, that's fine too. or, if you want to use this exchange as grounds for starting over with each other, that's always an open door with me. if you really want to talk about volumetric efficiency then we can.....you can't go from *** to nice guy in one post. at least I'm an *** all the time, I'm consistent.

and with all due respect, have a nice evening.

 

No you wouldn't

 

well that was anti-climatic.

 

Generally, a few inches shorter than you need it to be.

 

 

Using big words again also you might want to try this

CFM = (CID x RPM x VE) / 3456

 

 

When data logging my C7 after installing an AFE cold air intake--- It showed that the ECM was adding 13% more fuel for the added airflow- during P/T-----to correct for the leanness you need to add that 13% in your MAF HZ table to compensate--- P/T fuel is normally up to about 6500 HZ in your MAF table----At WOT or power enrichment--more fuel is needed as well--Not the whole 13% but the exact % can be realized by using a wide band O2 ---Typically a 13 % leaness at P/T at PE would require about 1/2 as much % at PE or WOT --this can be achieved in several ways---1 is to add 6.5 to the MAF table from 6500 hz table on up---OR the lower the PE value 2-3 tenths richer--All of this is trial and error-- to be verified using a wideband 02---
More airflow requires more commanded fuel----

 

we have been over this, DO. NOT. CORRECT.FUELING.WITH.PE. the pe tables are for commanding fueling, the maf table is for correcting it to match commanded.

you say you are a tuner. please tell us what shop you work for so people know.

 

Did you check your A/F after the AFE install? I was told by someone who tested one that the AFE intake size at the MAF sensor was so much larger than stock that it forced the A/F at WOT to go to 14:1

Actually, that number is in line with the 13% additional fuel number you quote. Sounds like the AFE requires a tune to use.

 

hmmm

 

Something wrong with the equation?

 

no. just not sure why you posted it in the first place....not to mention your obligatory derogatory comments, and you ask me why I don't like you. using big words? anticlimactic is a big word for you? or just autocorrect iPad typing? this is 2015, not 1945. let's get on with it.

if you want to say something, say it. if you have something to teach the forum, teach it. I can't decode your posts and I am not inclined to elaborate on supposition.

spit it out man.

 

Yes I checked the P/T fuel before and after the AFE install----The ECM at P/T with the AFE was adding 13% more fuel to achieve the AFR of 14.10----By making a MAF adjustment eliminates the "learning process" of the ECM to self correct to the stoich of 14.10--If you did nothing it would eventually learn out on it's own after 50-75 miles of normal driving
During PE or at WOT is totally different---The fuel is at the mercy of your commanded fuel in your tune---Before the AFE my WOT AFR was around 12.7 AFR on the widen]band in 3rd gear---Which is safe but these engines can be run leaner and safe
After the AFE install the WOT AFR went to way lean--similar to your's in the low 14's---The ECM also pulled timing and it showed about 19-21 * of timing only due to pinging----
My conclusion is that the AFE re-location of the MAF sensor and the more free flowing air intake required adding fuel--I chose to do that by adding fuel with the MAF table from 6500 HZ on up---I started by adding 3%---Immediately the timing came back to the 23-24 range and the air flow measured an increase---which equals more HP
I then added again another 3% with the same results--airflow increased as well as timing into the 25-26* range--Wideband now shows an AFR back into the low 13's ----No KR or no pinging either---
When I have time I will again add more fuel to shoot for a safer 12.7 to 12.9 area---These engine like fuel---These changes were all done on GAS---after the E85 conversion I've noticed that the timing has increased into the 27-28* range---still no KR and pinging---haven't checked the AFR with the ethanol yet---But I am guessing that the added fuel will only create more airflow and HP---
These E92 ECM's are complex---tuning to date requires trial and error---Bottom line with the AFE--the stock tune needs more fuel to make more HP--otherwise you lose a lot of timing as mine did into the 19's---Right now I'm at a plus 6% on the MAF table above 6500 HZ results have been great--timing has jumped into the 25's and the airflow shown by the MAF has jumped into the 50 lb area---( stock was in the 46 lb area)
Others may have experienced different results---these are only what my experience has shown--

 

The point I'd like others to take from this is that the AFE intake is not plug and play. You will HAVE to tune the car to run one.

 

That's great info, thanks! I was always under the impression that if an intake didn't require a tune then it wasn't a very good intake, or at least not much better than stock. I know things change over time and the ability of the computer to self adjust is getting better and better though.

Your comments make me think that this engine might pick up a little from octane, if the timing self-adjustment window is that big I'm curious if anybody has tried 97 or 100 octane and logged the timing.

 

they all do. companies say they dont so you arent afraid to buy it.

no different than any previous vette or camaro.....or truck.



seriously guys, this is still an engine that pumps air tuned by gm. the only change is the ecm is torque based instead of airflow based, for calculations.....the 2000 corvette could benefit from octane and so could a 2015 truck. fuel trims are the same as always.

heres the difference.....people are starting to understand and talk more about whats inside the computers now. its just a sign of the times. but we arent discovering something new.

 

My last car was a 2012 GT and it had 2 factory widebands (and 2 downstream narrow bands) so the fuel metering was pretty accurate. The self adjustment window was very small though. There are multiple intake styles for coyotes that either require or don't require a tune, and it is my understanding that is related to the diameter of the MAF housing and overall air flow. That car did have a factory CAI that could support pretty big HP though. When I say they require a tune I mean the car doesn't run with the intake and no tune, most won't even idle. I'm surprised AFE put out a product that just makes the engine really lean and then brags about HP gains. Is there any merit to what they said about driving it 100 miles before you see the power increase?

The coyote could not however swing the timing 8 degrees as was indicated in this thread, it had the ability to go 2 degrees each way. Unless it was a super hot day or something 93 octane was enough to max out the 2 degrees of advance, so more octane got you nothing. If this car can keep advancing it until there's knock then I'm mixing some 110 the next time I go to the track.

I asked the top guys on the fast list what fuel they ran and nobody answered lol, maybe now I know why.