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Old 07-02-2019, 11:42 AM   #281
John V
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Not really ripping burnouts. Just 0-60 runs mostly.
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Old 07-02-2019, 02:05 PM   #282
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Not really ripping burnouts. Just 0-60 runs mostly.
Even that's impressive!
I've seen your driveway, which as you point out is long...but not that long.
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Old 07-02-2019, 02:25 PM   #283
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Even that's impressive!
I've seen your driveway, which as you point out is long...but not that long.
I mean it's 2,700lbs and makes 400hp at the wheels. It's not slow.
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Old 07-02-2019, 02:45 PM   #284
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Um... do you mean the driveway right in front of your house? Or the shared road/driveway leading from the main road to your driveway?

One is slightly longer than the other.
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Old 07-02-2019, 02:46 PM   #285
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JV in his driveway:

https://youtu.be/Mfq_fed8h-Q
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Old 07-02-2019, 03:23 PM   #286
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Old 07-02-2019, 05:34 PM   #287
John V
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Um... do you mean the driveway right in front of your house? Or the shared road/driveway leading from the main road to your driveway?

One is slightly longer than the other.
The shared road. Back the car down the driveway so the rear tires are on Burntwoods, floor the gas, dump the clutch, achieve glory
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Old 07-07-2019, 04:39 PM   #288
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The shared road. Back the car down the driveway so the rear tires are on Burntwoods, floor the gas, dump the clutch, achieve glory


11s all the way up
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Old 07-17-2019, 07:12 AM   #289
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Now that the crank sensor issue is fixed, on to the next problem I've been having. The fuel requirements for this thing exceed the ability of the stock series 2 RX-8 fuel bowl to stay full. The volume of fuel inside the fuel basket is pretty small because the pump and filter assembly take up probably 80% of the volume. It's refilled by gravity. The other problem is E85 requires about 40% more fuel by volume than gasoline to achieve the same lambda. So a good pull at WOT drains the fuel bowl faster than it can refill. I've got a Deatschwerks 340LPH pump in the stock housing feeding a return-style system where the return dumps directly into the fuel basket. Below is a pic of the stock fuel pump basket.



The fuel bowl is filled by two sources - one is the siphon from the passenger's side of the tank, which is not very efficient. But the primary method it's re-filled is by gravity, through a small orifice at the bottom of the basket. Sorry for the blurry pics, they're not mine.



In the middle of the pic you can see a small piece clipped onto a plastic protrusion on the very bottom of the bowl.



That little flapper is a one-way valve that allows fuel to flow through the aforementioned pipe when the fuel level in the fuel tank is higher than the level inside the fuel pump basket. The idea being that the pressure is equalized when the levels in the tank and inside the basket are the same. The problem is that orifice isn't large enough to keep the fuel pump basket fed when the engine is at WOT. When the tank is completely full, overflow through the top of the basket is sufficient to keep it fed (plus the pressure through that orifice is greater), but as the level in the tank drops, that no longer works. It's easy enough to test - at the fuel rail if I disconnect the return hose and run the pump, after a few seconds the fuel flow slows down significantly as the fuel pump basket starts to run dry. Turn off the pump for a few seconds, let the basket refill, and pressure returns.

The flapper is much larger in diameter than the opening in that pipe. I didn't measure it, but it looks to be about 12 or 13 mm. I decided to try to open up that pipe a bit to improve the flow. The plastic is extremely brittle, so I drilled it out really slowly. An 8.5mm bit followed by a 9mm followed by 3/8", which is about 9.5mm. I didn't try to go larger because the plastic was starting to flex pretty badly. Going from 8mm (50.2 square mm of area) to 3/8" (71.2 square mm) is a 42% increase in area. I also modified the flapper so it can swing open a little farther. I'll test this later, but I'm hoping that's enough to keep the fuel bowl fed even when the tank is at 1/2 or less.

I got to test this at the event this past Sunday and it was a success. No more fuel starvation and even better, no misfires with the new crank sensor! The car was great. I had the car down around 1/4 tank of fuel and will try running it even lower next weekend.

I had messed with the boost control algorithm to try to make the boost level more consistent (it tended to hunt around the target a bit which led to more boost than I wanted) but it made things worse. I lost the super fast spool that I had before. I'm going to do some more testing this weekend to try to get the turbo to spool up faster. Overall though, really happy with how the car worked. It was a really hot day and the thing was just a trooper, no issues at all.

Last edited by John V; 07-18-2019 at 05:23 AM.
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Old 07-18-2019, 12:15 AM   #290
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Now that the crank sensor issue is fixed, on to the next problem I've been having. The fuel requirements for this thing exceed the ability of the stock series 2 RX-8 fuel bowl to stay full.
I can only imagine debugging and fixing issues like this. And then the next one. And the next one.

You're a brave (and patient, motivated, persistent, skilled...) man.
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