ok so here is the deal i just finished getting my 225 rebuilt so its going to be a driver again so i want to build a extra motor and balance power with economy
so this is what im thinking
170ci
10.5 to 1 cr
big valves (1.75 and 1.5)
hei style ign control
mpfi (mega squirt I)
intercooled turbo (6 psi for street 15 for track)
E85 with meth injection
balanced to 8k
and a a833 od if i can find one or a T5
goals are 35mpg freeway and 25 city with ~400hp
any ideas or sugestions and why (kinda a open forum thing just getting more ideas)
Just some thoughts here...
In the first place, if you want 400 horsepower, using a 170 is like getting into a fistfight with one hand tied behind your back. That much stress on a little motor like that is begging for problems. Use a 225... much LESS stress to achieve your desired 400 hp.
E-85 has so much less energy, the mileage will suffer greatly when compared with gasoline.... something like 30-percent, so if mileage is your goal, E-85 is probably the worst thing you could use.
Running a 10.5 compression ratio AND forced induction is not a very good idea, it seems to me, because of possible detonation problems (even with E-85's high octane.) I was told recently, that the E-85 that comes out of service station gas pumps is of a horribly inconsistent mix, and you cannot depend on the octane, because it may be E-85 one time and E-71 the next. That wouldn't work very well. Unless you want to mix your own fuel, it sounds pretty iffy to me... But you CAN buy it in barrells that are pre-tested and have a guarnteed correct 85% ratio, but that seems like a lot of trouble to go to for a daily driver (which I assume this to be, since you're interested in "mileage.")
All this is just MY OPINION, and I am surely not an expert in any way, on /6 turbos, but from what I have read on here and the /6.org site, turbos work well when "held back," and I think a 904/999 lockup-converter transmission might actually be a better deal for you, seeing as how the constant drag through the gear changes would keep your turbo spooled, and your top gear would still be 1:1, (unless you run an overdrive 4-speed,) with no slippage, dut to the lockup converter.
But, trying to get 400 horsepower out of a 170 for the street, would indeed require some high rpm that wouldn't give you the kind of reliability and drivability that a street car needs to have.
Do it with a lower-revving 225... and you'll have a more long-term maintenance-free machine, I think.
Just my 2-cents:salute:
