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(The rennlist iPhone interface is the all time low in interface design, trying to edit with photos is ridiculously user unfriendly and frankly buggy.)
While I spent three days loosely supervising my offspring on the slopes...
...John Kuhn has been busy getting the data flowing in the shop:
A very temporary intercooler shroud installed:
Sensor wiring loom is complete:
The exhaust manifold (cycle average) pressure can be measured with cheap sensors and the cooling coil length isn't an issue:
And we're getting some data now:
We can get a fast enough thermocouple in the exhaust manifold pre-turbo, the cooling sleeve creates too much inertia. We may end up having to back out the exhaust manifold temp from the other data.
John's testing a couple of ways to better mimic the driving conditions on the dyno. The intercooler temperature drop is something that he wants to get ballpark right. There's a shroud and a fan that nominally moves 1600 CFM without any restriction. Thru the funnel, shroud, and intercooler it will move a lot less, of course. The highly scientific computations on the shroud itself suggest that the nominal air flow would be equivalent to about 120 km/h air speed, but half that is probably more realistic?
The variable non-labor cost of the shrouding technology was $11.20 all in so although no billet parts were CNC machined in the process, the benefits clearly exceed the costs!
... There's a shroud and a fan that nominally moves 1600 CFM without any restriction. Thru the funnel, shroud, and intercooler it will move a lot less, of course. The highly scientific computations ...
Same Reyonlds number? Cardboardputer screen leads to doubt.
edit: Scratch that. Heat transfer, speed and mass. Not friction and momentum transfer.
Same Reyonlds number? Cardboardputer screen leads to doubt. edit: Scratch that. Heat transfer, speed and mass. Not friction and momentum transfer. The shroud is awesome.
The cardboardputer screen shot didn't consider the Reynolds number, but the flow in the shroud is highly likely in the turbulent regime. Where the Reynolds numbers start mattering is inside the intercooler core. Those are what they are and I'm assuming the core designers worried enough about that. As your edit says, we just need to move about realistic amount of air mass thru the intercooler at near atmospheric temp and pressure.
The baseline pull is about 10 psi pull. Depending on the ambient conditions, the dyno corrects it to somewhere in the 530-550 rwhp range. The dyno correction factors and the boost control are interacting in a way that I don't think the correction factors are really all that meaningful. Since these pulls are not about the power, who cares. The baseline is that ballpark power level.
John had all the data channels painting up now. At the baseline level, the compressor inlet pipe sees 0.3 psi vacuum. Given that the air velocity is pretty high, this is pretty much as good as it could be under Newtonian physics. The inlet and air cleaner will allow doubling the baseline power.
The second observation is that the new intercoolers are working extremely well. The intake manifold temperature is so low that I think John will need to make some tweaks to the censors to get more resolution there. The current thermocouples read +6F temp into the engine relative to ambient air. Even with measurement errors, that's removing about 150F+ off the charge air temperature. The discharge temp on the compressor is 250ish degrees F at 10 psig baseline boost. Intercooler pressure drop at the 530 rwhp baseline is 1.5 psi. To summarize: the ambient was 84F and we saw 90F at intake. Even if the thermocouples aren't that accurate, it's a massive temperature drop.
Note that the intercooler cores have the medium density "bump" turbulators. We could have gone with less pressure drop and less heat removed with the low turbulence cores.
Then there's the question what pressure drop will these cores cause at double the baseline power? That will be about proportional to pressure and about proportional to the square of velocity. Fortunately, twice the power isn't twice the velocity because pressure is increased. I'm guessing about 3 psi pressure drop at double the baseline power.
The turbine downpipe pressure is reading about 1.5 psig. That's with the dual 3" inch exhaust. The exhaust was perfectly fine on the 700 rwhp iteration , but doubling the baseline will likely cause a too high downpipe pressure with these pipes. If we'll see say 5 psi at the downpipe and run an absolute pressure ratio of 3 at the turbine, that's like 15 psi more at the exhaust manifold (not quite, but humor me). We can't allow that because the whole blue engine design with these exhaust manifolds relies on boost being close to the exhaust back pressure. So I wouldn't be shocked if we'll have to step up to dual 3.5" exhaust to get this engine to run efficiently at about double the baseline power. This will then of course make all the muffling challenges much harder.
One of the fun things of this projects has been exploring the limits of the stock computers.
At the previous iteration, we discovered that the superMAF setup in Sharktuner was limiting the EZ-K in a way that made the ignition table just a vector when we turned the boost up a little bit. This was with the stock engine and smaller turbo system. It was clear that in terms of torque production, we had gone far beyond where anybody else had gone with Sharktuner SuperMAF EZ-K computer. JDS got some data and quickly fixed the EZ-K maps to scale up to higher torque levels.
As noted earlier in the thread, to our knowledge this is also the first time 80lbs injectors have been running with modified stock computers. That was a likely first, but really not a limitation as those run just fine straight out of the box with a couple of tricks.
Now, we're knocking on the door of the LH mapping limits. Even with the adjustable grid definitions, we're limited to the maximum superMAF LH load signal of 300. John just knocked the door of that limit yesterday. If you go all the way to the limit and above, the engine will continue to run but the ability to tune it will not be there. At very rich and retarded, load signal of 250 gives about 540 ftlbs at the rear axle and load signal of 300 gives about 650 ftlbs. One can advance the ignition and lean it out to get some more, but in terms of additional air flow the current limit is there. Recall that this only with 12-14 psi of boost which is not even close to where this train is ultimately heading. We are just hitting the limits at lower boost levels because the blue engine and the new turbo system breathe so well.
Is this going to require another re-scale of the existing SuperMAF, or will you have to be a bit more elaborate?
Can you run 2 SuperMAFs? Can they be installed before your airbox that currently sets over the MAF? Some sort of averaging circuit would be required to run 2 I suppose.
This is not a recommendation, just a question.
Is this going to require another re-scale of the existing SuperMAF, or will you have to be a bit more elaborate? Can you run 2 SuperMAFs? Can they be installed before your airbox that currently sets over the MAF? Some sort of averaging circuit would be required to run 2 I suppose.
This is not a recommendation, just a question.
Originally Posted by V2Rocket
Just do it BMW V-12 style... two MAFs, two DMEs...run the engine as two separate banks
This SuperMAF sensor version itself I believe can measure the mass air flow upto a very high level. 6.2V is the limit and ballparking it 6V from SuperMAF corresponds to about 5000 kg/h which those who're into this kinds of hypotheticals is probably something like 1500hp? These compressors aren't going to 1500hp so that's completely hypothetical. I think it's the software in LH that constrains the map ranges. This is all computed based on integers inside LH by my guess so it makes sense that every variable has an allowed range. I haven't really looked into the true capabilities of the LH and EZ-K hardware myself, so I'm just guessing. John's got questions with JDS on whether they can take the stock computers further out.
We just got an experimental LH software from JDS that allows us to adjust the load row definitions up to MAF signal value of 400. The plan is to try that software next weekend.
John is back from a trade show and installing the new JDS software that goes not just to eleven but all the way to 400. He's also fabricating water traps for the exhaust side pressure sensor, as the sensor and cooling coil orientation is giving us condensation problems.
John ran one more pull with the old software for new baseline at 14.2 psi. 644 rwhp and only 10-15F manifold temperature increase compared to the 88 degrees ambient temp in the shop. Soon we'll see how the new software does.
In the meanwhile, I've been getting into the period-correct mood. RayBan, Diesel (was the new thing in the 1980's), All Star Converses, Delorean, and of course the 1980's **** 'stache!
I was searching everywhere for the flux capacitor, but couldn't find it.
You can get it there just by ordering? And silly me, I was looking for it very hard, even having to perform that rather invasive search in the picture.
On other news, the news JDS software runs with the load rows going to 400. Not tuning there, John has just checked that it runs fine at the 645 rwhp level with the news software.
In the end, the second highest load row will be set to about max boost and torque on 93 octane pump gas. I'm guessing around 300?
03-19-2017, 09:42 PM
Data finally flowing, no power numbers yet though
