big boost with pump gas & meth/H2O

[CSXT802]

For those of you running high boost with pump gas & meth/H2O. What is your set up and how far have you pushed it. I'm asking because on my way to work this morning, I did a forth gear pull and sent the boost gauge past the 30 psi mark (I'm guessing 32 psi) Wide band showed 11.2 for the A/F. This was with a 5 GPH nozzle 2/3 meth, 1/3 water mix.

[CSXT802]

[BadAssPerformance]

I'm not a meth user, but 11.2:1 sounds ok

[Juggy]

im running 26psi on PUMP gas no meth

[2.216VTurbo]

Not running Meth on my cars but my neighbor with the 8 second Fast Fiat and I have been messing with it on his car the last 4 years. He runs SDS and 96PPH injectors. What we found by looking at the wideband AFR's is that once the meth comes on, the readings are totally unreliable We would get this huge lean 'spike' as soon as the meth started spraying for the first season we tried to adjust for it, IIRC we were up to 20GPH nozzles, the motor was laying down it was so over fueled but the AFR still showed lean. We kept cutting back the meth over the next two seasons (I think were at 12GPH nozzles) and the car got faster and faster. His doesn't come on till 22PSI, are you able to look at AFR's just before the spray starts? IMO, that's the only reliable way to read them.

[Ondonti]

stop using water, o2 sensor problem solved, 4 years wasted.

[csxtra]

I was running pump gas/100% meth at the track for a while, but I ran into a detonation limit at around 32psi.

This is on a 2.5, G-head (Menegon +1mm with enlarged combustion chamber for reduced knock sensitivity), T3/T4-Stage3-.63AR-50Trim-T4Cover, AlkyControl progressive system with 12gph nozzle, set to come on at 23psi, and ramping up to max pressure @29psi (where 3-bar map goes blind).
My AFRs were always in the low to mid 11s. I was using the alky system as an "anti-knock kit".

I tried cutting fuel and increasing meth (with a custom "alky" cal) at high boost, but the head kept lifting from detonation in the front (cometic HG, ARP studs @ 95lb-ft). My theory is that even though the combined effective knock resistance of the pump/meth is high, the pump gas is still autoigniting, causing the knock.

Now it could be alky distribution issues (I'm running a single nozzle upstream of the throttlebody), but I'm not going to investigate further.

From now on, I'll be running C16 with no alky for safety at "all of it" boost levels at the track, and pump gas and straight meth for 24-29psi on the street.

Just another datapoint for your investigation, hope this helps.

[2.216VTurbo]

stop using water, o2 sensor problem solved, 4 years wasted.

No water anywhere near that motor, it's aircooled with strait Meth...

[turbovanman²]

From now on, I'll be running C16 with no alky for safety at "all of it" boost levels at the track, and pump gas and straight meth for 24-29psi on the street.

Just another datapoint for your investigation, hope this helps.

I agree, my Rotary guys are using boat loads of meth on there cars now-turbo 4's and 6's too, using real fuel injectors, these guys are dumping huge amounts in and still use race gas.

I use alky for the street as i can run lower octane gas and keep a nice fat spark curve, but for the track, $$40-$100 for C16 is worth keeping my engine together. I know the AF reading changes but buy how much, I am not sure.

I guess if you have the knock sensor hooked up to flash the CEL light and its not, your still safe.

[CSXT802]

Thanks for the input everyone. I had not planed on going above 30 psi, but this new to me turbo has a mind of it's own. In the lower gears it's fine but when I put a load on the motor it wants to shoot to the moon.

[contraption22]

Ive run up to 30psi on pump using Blue Washer fluid on a 3gph nozzle.... but the car is faster on ravce gas with the injection off.