ALPSTA

iTrader: (3)

I need some advice from experienced members on which way to go for AI.

Little background info:
My car has a GTX35R single turbo kit. AEM water/meth injection kit is already installed with the biggest size nozzle installed on greddy elbow. My ecu is apexi power fc. I have all the necessary injectors, cooling parts etc. The wastegates have 12psi springs and we are planning to run 15-16psi for low boost and 18 or 20psi for high boost.

When I bought the car we had Euro Shell 100 and 98 octane fuels available which are probably equal to US 93 octane, then we had 97 octane but now we only have 95 octane which is probably equal to US 91 octane.

I will have my car tuned next week and considering the octane situation what should I do to keep my engine safe but also powerful at the same time? Planning to attend a trackday at the end of this month.

a) Tune with water only. Add water/meth after tune if necessary as a safety measure.
b) Tune with water/meth. This will probably give the best whp but also be the riskiest.
c) Tune with no AI and add water or water/meth in the future if necessary as safety measure.

bumpstart

IMO in a simple system with no level sender and or failsafe signal for the ecu then you should always err for option C

it may run less timing and have slightly less power overall than the other options but you do double yourself for safety factor which is something to consider when tracking

if you want maximum window against detonation then you should mix at MW30 proportions with genuine methanol

ALPSTA

iTrader: (3)

Thanks Bumpstart, I think that's the best way to go. Better to sacrifice some hp in return for reliability. Does it matter what I inject after the car is tuned (water vs water/meth)? Meth may help a little with the crappy octane we have here.

Sgtblue

iTrader: (16)

I'm with Bumpstart. In my experience, with properly sized nozzles and option 'C', I don't think you'd notice much, if any, power loss in your seat.

lOOkatme

iTrader: (19)

I tuned my car without AI, I added water injection only for safety. Maybe a little WHP lost, but it isn't much. Car does ull rediculous amounts of vacuum under idle after installing water injection. I also notice my turbo spools faster or was cleaned out or something. I might lean out the upper cells a tad (11.0 to 11.6) and then add a little methanol to get that benefit as well to bring it back to low 11's.

ALPSTA

iTrader: (3)

AEM water injection kit comes with 3 nozzles, I installed the biggest one which is 630cc/min I think and the medium one is 315cc/min or similar...