Engine Analiyzer Pro: modeling the Stock 4.0 & Bolt on mods

[Flash]

These are variations on the original Rhoads lifter, http://www.rhoadsproducts.com/. Oem in the Viper, http://www.camaros.net/forums/showthread.php?t=35628. They work
John

Thanks John, for the link, Vary informative, as always. Didn't know about Rhoads new lifter.

I like the idea of being able to have control of the "lift" bleed...............Vary cooooool. Thanks!!!


Flash

[John]

2016xl is a nice lifter for well built I6 motors. Wonder why the mopar performance book has a pic of a old Rhoads lifter ad in the middle of the publication! Good to hear from ya.
John

[Cheromaniac]

So here's some basic tests of the current revision of Sim4.0, first I ran the bone stock setup, and then changed only the intake manifold to the simulated 99+ intake. As you can see it looks just like you would envision it, if you've been reading Dino Savva's and Lee Hurley's remarks about it over the years:

Dino Savva has always maintained it's worth about 3 or 4hp and Lee Hurley has said it's main benefit is a nice low and mid range (and peak) Torque bump of around 10 foot pounds through the band. Anyone who follows the HESCO board will know what I'm talking about. Looks like they're both right as far as EAP is concerned. It's important to understand that these number are derived from actual differences in dimensions between the two intake manifolds, That is the runner lengths, plenum size, degrees of taper, and "flow coefficients" of the two manifolds, the squared (90* to the plenum) HO log being much worse than the smoothly curving 99+.

Here's some more info. on the older and the newer style manifolds:

Runner length: 9.5" both manifolds.

Runner c/s area: '91-'99 manifold 2.234 sq.in., '00-'06 manifold 1.928 sq. in.

Runner volume: '91-'99 manifold 21.2ci, '00-'06 manifold 18.3ci
Plenum volume: '91-'99 manifold 31.5ci, '00-'06 manifold 152.6ci

The distance from the intake valve to the port opening in the 4.0 cylinder head is 3.5", making the total distance 13" from the manifold plenum wall to the intake valve. The port volumes of the stock 4.0 head are 112cc intake and 73cc exhaust.

Can you try running these numbers in your dyno sim to compare the two manifolds on a stock 4.0 engine? I'm curious to see if the difference is still going to be 3hp/9lbft if you also use the head flow and cam specs from my page http://www.jeep4.0performance.4mg.com/tech_specs.html

[1bolt]

With all due respect, We're WAY ahead of you dino The posted runs were already using accurate numbers. It's a measure of the respect I have for you, that your post had me scrambling around to triple check everything.

To set the record straight, I measured down the centerline, several times for each port and runner using copper wire to try and mimic the profile as closely as I possibly could.

Intake runner lengths are:
HO log: 8"
Renix Log: 7.5"
99+ equal runner 11.5"

As you can see the 99+ has much longer runners meant to tune for more low torque. It's a testament to the excellent smooth flowing design versus the awful squared intake that it picks up any horse power at all. This smoother flow is quantified by comparing the port flow on my bench, to the port flow with either intake manifold attached... The difference in flow is used to calculate a flow coefficient that tells EAP how good or bad the manifold is.

The intake port is certainly not the same centerline as the exhaust, as you can plainly see the intake has a significantly higher roof than any HO head exhaust port. So the centerline couldn't possibly be identical unless the valve seats weren't the same.

intake is very close to 3 and 15/16th's, so I called it 3.9+ because the valve guide boss takes up a tiny bit of space that the measuring wire needs to occupy to mimic the port shape correctly, I am fairly confident that the port actually is designed to be 4" and the short fraction is my inability to measure the profile exactly.

The exhaust ports are closer to 3.75 than 3.5 but I sided with 3.5 in my early runs, and have since changed to 3.75 (again the guide boss).

I had derived the same plenum volumes give or take a few cubic centimeters (actually they may be identical I'd have to look) but thanks for confirming them...

I also found no significant cross sectional difference between intakes at the head port, using inside guages and a micrometer. The 99+ seems to have an intentional taper toward the plenum, but it's bloody hard to measure, I put it at 1* but it might be closer to 2*.

[Cheromaniac]

That respect is mutual Simon. I'm impressed with your attention to detail. It's even more obsessive than mine.
Do you think you can run the numbers for both manifolds on my "poor man's" stroker?

Displacement 4563cc (3.895" bore and stroke)
9.25:1 SCR
57cc chamber, 0.043" HG (bore 4"), 0.045" deck clearance, 17.5cc piston dish
Stock '92 cam
Ported 7120 head, stock valves (assume 4% more intake flow and 17% more exhaust flow than stock)
Cold air intake
Mustang 65mm TB
Borla header
2.5" low restriction exhaust
Electric fans

[1bolt]

I sure can Dino, in fact thats where all this is heading, I kind of want to follow a linear upgrade path like the average user here might. getting to strokers stuff after hopping up the 4.0 a little more. Forced induction scenarios and at some point build the ultimate simulated stroker. The results should be good guide lines for how to make certain levels of power/torque that meet different build goals... Like crawler versus street, or Land Speed record. I am running some numbers for Pete (Plechtan) to help him optimize what he has, and look at verious things he can do to build high RPM horse power. 48" long exhaust primaries and 6.5 inch intake runners with the HESCO head numbers puts his build a little over 400hp, I simulated hogging HESCO's head out to get somewhere closer to 300CFM and the curves went up 50-60 pound feet and hp. All of this is very peaked way above a streetable RPM of course...

[Cheromaniac]

I had a go myself using the demo version and this is what I got comparing the old and new manifolds:

Stock 4.0: Old 190hp@4900rpm/224lbft@3800rpm, new 191hp@4900rpm/229lbft@3700rpm, biggest gain 5lbft at 3700rpm
My 4.6 stroker: Old 248hp@4900rpm/306lbft@3500rpm, new 244hp@4600rpm/312lbft@3400rpm, biggest gain 10lbft at 3300rpm

The torque increase on a stock 4.0 was small and mainly in the 3000-4500rpm range. On my 4.6 stroker, the torque increase was more dramatic and mainly in the 2000-4500rpm range. Above 4600rpm the newer manifold lost a few HP. In both cases the newer manifold shifted the peak HP and TQ points to slightly lower rpm especially on the stroker.
I didn't have the choice of curved runner manifold so I couldn't model it for the newer manifold.

[amcinstaller]

as well as dino, ive dl'ed the demo, and i like it so far, but im only learning all of this. some of the more in depth stuff is admittedly over my head. but i like the look of this program and will definately be considering the purchase of it. so, early on in this thread you made mention of making your profile files available for download. is this going to come soon, it looks like this will be a neat thing to play with!

[1bolt]

I will be, I just don't want to put them up until I'm happy with them and consider them as accurate as I can make them. This thread is unfolding at the exact same pace as I am running things and tweaking the model... for instance I haven't simmed Borla long tube headers, or any popular RV cams yet. So basically this thread is part of the refining process for the Engine files. the first things I did were relatively predictable or already dyno'ed by other people so I could confirm the accuracy and show in the thread that this program doesn't throw silly numbers around.

Dino, it took me several weeks to get all the right inputs, I had "realistic" looking results many times but later found things about EAP that made me go back and tweak for more realistic numbers. In fact if you read the whole thread you'll see that I mention that specifically. Having read most of the manual it becomes clear that there are many inputs and options that SOUND like they would be fitting for the 4.0 but end up being wrong. In fact if you intuitively set up some stuff like you would THINK at first blush you should; you will get an unrealistic torque curve. After reading most of the manual these things become more obvious.

For one thing EAP seems to have 60's muscle car engine technology as a baseline... Modern engines have much better combustion efficiency. "typical Wedge" chamber shape would at first blush appear to fit the 4.0 but that setting is more of a 60's closed wedge chamber with only nominal quench area. That is to say a larger cc chamber, one quench pad and usually flat top pistons. The 4.0 is actually closer to a compact wedge (somewhat in between), based on the description in the manual... two quench pads, central spark plug, smaller chamber with piston dish making the total chamber volume instead of most of the volume being in the head. SO you either need to tweak efficiency up to +10% or leave it as zero and select "compact wedge" which results in a 4.0 that is just a tad better than factory ratings (like 8 or 10hp better). On your web page you do mention that you think the factory ratings were just a bit conservative... I agree for that's worth.

At this point I think I have a pretty accurate model, mod results seem fairly accurate based on what dyno info is out there... As long as my numbers are a touch lower than HESCO's "optimistic" dyno I'll be happy.

[Cheromaniac]

Keep up the good work Simon. You could spend hours playing with EAP and it can become rather addictive. Ask me how I know!
As far as the old manifold v new manifold story goes, even though my HP/TQ gains numbers are more conservative than yours we still agree on the end result i.e. no torque gain at low rpm but a good torque gain in the midrange.

[1bolt]

Keep up the good work Simon. You could spend hours playing with EAP and it can become rather addictive. Ask me how I know!
As far as the old manifold v new manifold story goes, even though my HP/TQ gains numbers are more conservative than yours we still agree on the end result i.e. no torque gain at low rpm but a good torque gain in the midrange.

Yeah, at least acourding to EAP there's not a whole lot anything can do to increase torque at very low RPM's like below 2000, I'll have to see what an RV cam does but I don't think even a cam will have a big effect at least that's my hunch.

I may be wrong but i'm thinking that bore and stroke are the overriding factors for torque below 2000 rpms, down in that range, tuning effects seem negligable. Air is moving so slowly that if you tried to tune for inertia filling you'd have to use such a small pipe (or long one) that it would choke the engine at higher RPM's.

There are some things that can effect VERY low torque, swirl and the best "heart shaped" compact chambers... Super chargers, compression ratio is a biggie... among others.

[Cheromaniac]

Yeah, at least acourding to EAP there's not a whole lot anything can do to increase torque at very low RPM's like below 2000, I'll have to see what an RV cam does but I don't think even a cam will have a big effect at least that's my hunch.

I may be wrong but i'm thinking that bore and stroke are the overriding factors for torque below 2000 rpms, down in that range, tuning effects seem negligable. Air is moving so slowly that if you tried to tune for inertia filling you'd have to use such a small pipe (or long one) that it would choke the engine at higher RPM's.

You've got that right Simon. A smaller cam, smaller port heads, and a longer stroke increase torque at lower revs but at the expense of higher rev torque. My own personal preference is to get as much area as possible under the torque curve from 750rpm idle to 5250rpm redline. It seems that the newer intake manifold does help in that respect.

[amcinstaller]

hmmmm. im having some trouble getting a decent starting point for this. right now my numbers come out at 215 hp and 250 ftlbs. my best guess would tell me that theres a big difference using flow table data vs specifying a coefficient. i picked up this program, and i hope to master it soon, or at least eventually.

[1bolt]

I haven't played with single coefficients yet Dino has head flow numbers on his website that are accurate (except the 0331 flows seem to be low compared to mine and Alex22's flows which could have just been that 0331 head having a poor factory valve job) I think single flow coefficients assume a certain amount of optimization. It is definitely more accurate to input a flow table. There's also settings in the dyno run menu (calculate horse power) that will have important effects, like you can specify to use theoretically "just right" fuel and spark curves, which will result in a considerable boost in power and torque.

I am meaning to play with fuel and spark later, and I just have basic default fuel and timing trim numbers in there now, because I am no expert on what the 4.0 needs, not having tuned an engine managment computer on a real dyno yet (by the way getting more accurate numbers here is one of the things I wanted to get done before putting the engine files up for download). Maybe you and Dino can help with the fuel and spark curves? One of the reason I started the other thread asking people to help me gather measuments was this sort of thing, it's very time intensive to try and accurately measure inputs for everything. I am only today expecting to weigh all the valve train components, because I have a few hours off to do it.

If you look at Comanche91's unichip dyno tuning there's a pretty good example of getting some serious power gains out of going from factory fuel/timing trims to well tuned customized ones.

This is also an example of where getting more "realistic" could make other assumptions wrong, or exaggarate the effect of other assumptions. Like +10% burn efficiency with typical chambers. If every input was perfectly realistic that number may be +5% or +15% or 0% without being an expert in combustion efficiency the only way to know is to get everything else as close as possible and extrapolate that input.

It is an assumption or extrapolation to be sure, and right now with my inputs as accurate as possible for everything except fuel/timing and also valve train weights (I haven't gotten those things weighed yet) it may need to be tweaked. It's a dynamic model and as the user manual states several times, the more honest your inputs and the more you understand what the inputs actually MEAN to EAP the more accurate the model becomes.

One other thing to check is intake manifold heat... if you have "none" in that setting, you're simulating a VERY insulated intake tract. And you will get a nice boost in power... Chiefly because the 4.0 has a very heated intake manifold due to the headers being under it. I used the "reduced heat" setting which seems to be accurate, and from a "description" standpoint (i.e. EA pro's user manual description) it is accurate. But I'm inclined to think that I should actually be using "full production heat". Even though the 4.0 does not have engine coolant flowing through the intake like the old 258 intake does, the lack of cross flow all by itself might really put the intake temps up in the same area as a V6 carb intake with exhaust thermactors or coolant warming the intake manifold.

This may be one of those settings that will change as I get more concrete numbers for fuel and spark and valve train weight.

[Cheromaniac]

I entered a reduced heat manifold for my stroker 'cause I've insulated mine from header heat.