Worlds Fastest Comanche LSR build EAPro sims

[1bolt]

keep in mind EAP does not simulate idle characteristics, vacuum or bogging.... Which could come into play with a cam that aggressive, it looks like it makes about 6" of vaccum but that is just a WAG.

hehe Pete keep in mind your gearing and torque converter stall speed if it's an Auto, and your final drive gear ratio. If you don't get a push you might run out of gear before you run out of power. The push is mainly to allow gearing, and get past off idle bogging due to the gearing/cam

The torque down low is mainly a matter of that engine's basic stats, the compression the stroke and the displacement. and the fact that EAP doesn't simulate idle and bogging. That said I don't think a real world dyno operator will allow a pull from 1500 RPM's (or 2500 RPM's for that matter). So we'll probably never know.

At some point for shits and grins I'm going to put an RV cam in this simulation lengthen the runners and we can see what it would look like as a torque monster instead of a high RPM screamer.

I suspect it will produce more peak torque than Pete's build, and a huge chunk less horse power.

[1bolt]

Also to keep in mind, it runs on 112 octane race gas, is on the bleeding edge timing wise and has a very high "knock index" which means it will ping if it's not tuned extremely well. The real engine when Pete starts getting it dyno tuned will probably require a lot of tuning.

It will probably make less power in real life as some of EAP's parameters wont be able to be met, his exhaust ports will flow less, the intakes might flow less and be much bigger in cross section, and all will be effected by build quality (clearences) oil pressure (high oil pressure robs lots of hp) and a bunch of other possible factors.

[TurboTom]

Interesting stuff. It will be great when Pete gets it on a real dyno. Just to see how close you get.
Your program is putting out numbers that will be at the flywheel isn't it? And not adding all the enternal losses to the output?
This is at 5 liters correct?
100 HP/Liter is preaty strong for a 2 valve N/A engine at 6000 rpm...I like it!

[Plechtan]

It is a 5.0 (4" bore, 4" stroke) You cant set a record without pushing things a little. If you become a doantor, you can download the Desktop Dyno sheets from the donators forum. I am not sure about EAP, but Desktop dyno does take into account the water pump, but you are correct it is flywheel hp. We will be running an electric water pump and reverse flowing the engine so no lossed to the water pump.

[1bolt]

Everything I am doing with it is flywheel steady state dyno pulls, it can simulate a chassis dyno and acceleration pulls at variable rates (like SAE standard acceleration rates).

It is simulating electric water pump, among many other things like "ideal" ignition timing, and no outside heat in the intake tract.

Intake heat is a biggie, there's no way to specify non-cross flow heads, so intake temps will be higher than EAP thinks they will be.

I'm not trying to give excuses before the fact because we will indeed get to look at the real thing, but there are some real world factors that will effect the final plots that don't come into play in EAP.

I think it's extremely useful just being able to see what adding .125 to the cross section does, in an intake port while leaving the flows the same... Or lengthening primaries and intake runners. After a while you really get a sense of what is going on in such a complex system.

For one thing it's fair to say that making mods to an already built engine is really just an excercise in moving the torque peak higher or lower... It boils down to tuning where you want the engine to operate most efficiently.

So Tom you still want some runs done?

[Plechtan]

Were the runs done with as assumed 300cfm flow intake and 190 exhaust?

[1bolt]

Yep. If you get me the new flows and measure the port cross section now that HESCO has ported the head I can get you more realistic plots.

[1bolt]

Finally got the final head flows numbers from Hesco's porting work, fell short of the (probably lofty) 300 CFM goals, they did get 270 CFM. Here's the comparison to the "perfect" head in the last few plots so we know what the more realistic numbers are:

Unfortunately this doesn't tell the whole story as HESCO probably have opened up the cross section of the port (made it wider and/or taller) from what I have in EAPro which means the numbers will probably be lower than this.

Going to update this a few times tonight as I get a time to do more runs, I've been leaving Pete hanging due to family matters, thought I'd get this up there to get my ass in gear.

We're going to bump up the compression to 14:1, and play with the cam, and hopefully look at what effect making the port wider and bigger has on the realistic head simulation.

[1bolt]

Bumping compression to 14.0:1 basically resulted in a fairly linear 10hp gain with no other changes. Dynamic compression is 6.7 which is maybe a tad low, but I'm not sure about that for this lumpy a cam and peaky power curve so who knows... IMO it's out there on the bloody edge Pete if I was you I would go with 12-ish compression I'd have serious doubts about how long a 14 point CR motor is going to last without forged internals.

I know one thing I would be running this thing pig rich with the highest octane race gas you can find when you get it on the dyno for the first time.

[1bolt]

Okay Pete wanted to compare some variations of lobe separation, 114 versus 109 (108 to 110 I aimed for the middle)... looks like 114 will net more peak power but at a price in the midrange... Pete if you're confident that you'll have plenty of track to hit top RPM in top gear, then peak power matters more than a nicer curve. The 109 sep is a better all around choice by far. The 114 curve is darker blue and green, the 109 curve is light blue and red

Just another example of how you can make "more power" in an engine but have less overall power because of it...

Pete can you please look over my Cam specs that I have for both and confirm or correct them? I am no cam wiz and I think I might have total advance wrong but the number for total advance is intertwined with lobe centers, and separation. I don't fully understand the relationship.
check the specs:

and 109:

[Plechtan]

Both cam files look the same to me. It looks right, the only thing is that we are using .7 lift instead of .65 as shown. You would just change the exhaust centerline or the seperation, depends on how your software works. you could also play with the intake centerline to see what happens.

[lafrad]

I would try that LSA experiment again, but keeping the ICL the same in both... either both at 109 ICL or both at 114 ICL... play around with it that way. That will affect where the curves peak... you might find that cam profile with a 114 ICl and 109 ICL (5* advanced) might get that torque back....

[Plechtan]

Well we put the car on the dyno today. the curve is wery close to the plot labeled 270 cfm actual. I will post it when i get home. Looks like 1 bolt was right. I would like to thank him for all of his work on this project.

[Plechtan]

Engine HP.gif

Well here is the final dyno run, the purple line is the reading from the 02 sensor, and yes we are a little fat at 12.6. the line on the bottom is the fuel pressure regulator and that seem to hold steady at 41.55 the dip beetween 3,000 and 3,500 is the dyno loading up. ( water dyno).

In the simulations they generally showed the peak HP ( with the 270cfm head) at 6,000 rpm. Our peak was at 5,900 . Hp on the sim was 450, on the dyno 443. so within 2% not bad. Torque was also very close. I guess there is somthing to this simulation software.

[SilverXJ]

Is the 12.6 AFR on purpose? If not, do you think it would make any more power if you leaned it out some?