Quote:
Originally Posted by strombomb
Also, at 26 psi, you should be seeing 500 hp at the rear wheels (being that the b5 S4 guys with rs6 turbos are easily seeing 450 at all wheels). I can’t wait to see how your dyno session goes. I’m sitting in the edge of my seat!
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The results are in, power was a bit inconsistent during the day because of temperatures, it made between 470 and 488bhp on pump fuel, when I added the water/methanol injection (50/50 mix) it made 530bhp and 540ft/lb of torque. These numbers are at the flywheel. A bit lower than I expected, on a Mainline dyno which apparently read a bit lower than others. It worked hard to make those numbers, raised the rev limit up to 7200rpm as it was making power at the top end and it was running 1.8bar on petrol and 2bar on meth.
The interesting bit is probably temperatures. The car made 83 pulls so things got hot. Ambient inside the building was about 20c degrees during the morning. All the pulls were on petrol only. My charge cooler coolant temperatures were consistently around 30c for the inlet, the outlet would go to about 40c after a pull. IAT's were 30c up to 55c by the end of the pull. Not brilliant but acceptable, maybe the pump isn't fast enough?
We stopped for lunch, in the afternoon the ambient temp was up at 27c and everything had heat soaked, my charge cooler coolant was sitting around 40c and not coming back down much. IAT's were climbing to 65c at that point.
Right at the end we did 2 runs back to back, one on meth, one without.
On meth IAT's went from 35c, when it kicked in they dropped to 22c, by the end of the pull they were 36c. The initial drop might be the sensor getting doused with it. The charge cooler inlet liquid went from 32c to 42c, outlet was 41c. The EGT's peaked at 815c.
The next run was 0.2 bar less boost, no meth. IAT's went from 35c to 65c, inlet coolant went from 32c to 37c. Interestingly a few seconds after the run the inlet coolant kept raising to 41c, I guess this is the heat put into the system from the 1st pull, it shows not enough capacity in my system (probably about 10 litres) and the radiator isn't efficient enough to cool it back down fast. The coolant outlet was 48c on that pull. My EGT's were 900c.
Going by the difference in EGT's you can tell the water/meth is definately keeping things cool and it's not just a case of tricking the IAT sensor. My timing was about 5 degrees more advanced on the methanol.
It's kind of exactly what I thought, charge cooler gets overwhelmed, it'll be interesting to see where it ends up after a 1/4 mile run, I think it won't cope, even with it starting at near ambient temperature. Definitely not up to a trackday (but is any water to air system?). Like I said before, improvements to the efficiency of various parts of it are going to be marginal gains, what's a 5c improvement if your at 65c to start with?
If I was to do it again, I might be tempted to sack off the charge coolers and go for a more fancy water/methanol set-up, a couple of nozzles pre-turbo and one in each port to ensure equal delivery.