I want your spool data!
#301
Tweaking Enginerd
iTrader: (2)
Join Date: Mar 2013
Location: Boulder, CO
Posts: 1,809
Total Cats: 366
Don't be surprised if the e85 doesn't improve the spool RPM, might actually hurt it. I haven't been able to find any direct discussion on the topic, but e85 has a lower EGT, and the turbo is harvesting heat energy.
#302
If not the thing's going to be a slug when I bolt on a potato. Maybe 2560r. Different thread for that haha
#310
Tweaking Enginerd
iTrader: (2)
Join Date: Mar 2013
Location: Boulder, CO
Posts: 1,809
Total Cats: 366
fascinating ... had not considered the oxygenation component. Would still love to see an apples to apples comparison (which may not be fair due to flame front speed) with turbine inlet pressures and EGTs recorded. May be more proper to compare MBT tuning, but that introduces a fair amount on complex interaction churn. I will actually be in a position to take this measurement at some point here this summer (hopefully ...).
#313
fascinating ... had not considered the oxygenation component. Would still love to see an apples to apples comparison (which may not be fair due to flame front speed) with turbine inlet pressures and EGTs recorded. May be more proper to compare MBT tuning, but that introduces a fair amount on complex interaction churn. I will actually be in a position to take this measurement at some point here this summer (hopefully ...).
You get more power from E85 because it's got higher octane (so you can advance the timing/run more boost and thus turn more of the heat energy into useful work), and because it's got a higher H/C ratio than gasoline does. Combining oxygen with hydrogen releases more energy than combining it with carbon does, so for a given amount of input oxygen (which is ultimately what displacement, boost, VE, etc are all about), you want to maximize the amount of H you burn. Methanol is better than ethanol, and pure hydrogen is even better than that. High performance rocket engines burn liquid hydrogen with liquid oxygen, partly for this reason.
What that means for spool -- more timing means more energy in the piston, meaning less in the exhaust for the turbine to use. OTOH, more energy in the piston means the engine accelerates through the RPM band faster, meaning it gets to the higher-flow revs sooner, and the higher H/C ratio giving more energy overall means that even if you're getting a lower percentage of it in the turbine it's coming out of a larger total. Empirically, as Savington says, it doesn't really make a significant difference either way, so who cares.
--Ian
#315
Senior Member
iTrader: (1)
Join Date: Apr 2011
Location: Jonesboro Arkansas
Posts: 553
Total Cats: 25
Engine: 99 1.8l
Turbo: GT3076R 56 .60 A/R
Manifold: BEGi CastExt. Wastgate
Downpipe Size/Style: Single tube 2.5"
Exhaust Size: 2.5"
Exhaust Components: Resonator & Magnaflow Muffler
Intercooler Core Size: BEGI #2
Intake Manifold: Stock
Headwork: unknown
Engine Management: Hydra
Other Spoolin' Helpers/Hurters: Basically FM plumbing
Trans & Rear End Ratio: 5-speed, 4.1 LSD
Rear tire size: 225/45/15
Fith GEAR PULL:
RPM Boost(psi)
2700 0
2800 .6
2900 1.8
3000 1.8
3100 2.4
3200 3
3300 3.7
3400 4.9
3500 5.5
3600 6.1
3700 7.3
3800 8.6
3900 9.7
4000 10.4
4100 11
4200 12.9
4300 14.1
4400 15.3
4500 17.2
4600 17.3
4700 18
Long spool?
Turbo: GT3076R 56 .60 A/R
Manifold: BEGi CastExt. Wastgate
Downpipe Size/Style: Single tube 2.5"
Exhaust Size: 2.5"
Exhaust Components: Resonator & Magnaflow Muffler
Intercooler Core Size: BEGI #2
Intake Manifold: Stock
Headwork: unknown
Engine Management: Hydra
Other Spoolin' Helpers/Hurters: Basically FM plumbing
Trans & Rear End Ratio: 5-speed, 4.1 LSD
Rear tire size: 225/45/15
Fith GEAR PULL:
RPM Boost(psi)
2700 0
2800 .6
2900 1.8
3000 1.8
3100 2.4
3200 3
3300 3.7
3400 4.9
3500 5.5
3600 6.1
3700 7.3
3800 8.6
3900 9.7
4000 10.4
4100 11
4200 12.9
4300 14.1
4400 15.3
4500 17.2
4600 17.3
4700 18
Long spool?
#320
--Ian