my car is a 70 camaro, and i have been playing with the 307 engine latelly because of is low budget enviroment...hahaha (i use to have it in the last corner of the shop collecting dust) so.. re ringed,put some 250 (l6)pistons that lower the c.r to 8.4/1, fit new bearings, and made some log manifolds collecting to a single 60-1 turbonetics . non intercooled.... feeded via self made tbi, on 4 1000cc rochester injectors.megasquirted...off course.
using single stage wather/meth injection 550 nozzle activated at 12 psi.

the car is a real dog....i start at 26 degrees spark @3500 an 15 psi.... but it seems to flood in water as soon as the water injection comes, so i carefully added timing 2 degrees at the time... currently i use 34.2 degrees @ the same presure and rpms, and it seems to tolerate the water/meth a lot better, also it feels twice the power than i feel @ 26 degrees. and still cant feel any pinging or show any detonation signs...but it seems to my like a lot of timing.

i don´t have much previous experience with stock headed sbc¨s and no previous experience with any 307 sbc. but i made installs an tuning in 4 cylinder cars since 94.... so i´m worried because i never use so much timing in the litlle 4 bangers.

is important to note that i live in bogota at 8500 ft altitude....so my initial map reading is 73 kpa´s and 15 psi is around 169-175 kpa´s

any one can help my?? i don´t know if i can still add more timing??? cause i don´t want to hurt the engine, before i can take it to the track....

other than that, my coolant sensor, shows that the engine go colder as i use it under boost....so my initial think is that it will be safe to add more timing, but prefer some advise before the next try.

thanks
JKK

 

I'm not a SBC guy BUT a few questions:

What A/F are you running under boost?

What is your meth mix 50/50?

What RPM does the meth come on at?

What are you gapping the plugs at?

 

Out of boost and at that altitude with that low of compression id imagine it would need a lot of timing, but 15psi at sea level or at 8500 is the same thing correct? How do your plugs look? You say the enginge temps get cooler under boost, so maybe the only way your getting away with all that timing is its super rich. What's your ratio of water/meth, cause don't forget meth is fuel

 

no, 15 psi at sea level is 200 kpa, 15 psi @8500ft is arouund 149 kpa , remember that the engine sees the absolute pressure not the manometric pressure.

as for the a.f is around 12.2 12.5, water/ meth around 80/20.

i.m thinking that i have choose a very bad manifold design for my low ci engine, thinking about swaping for the tpi one.probably i can pick some low end torque.

 

That is way to lean.

What rpm is the meth starting to inject? What size nozzle?

 

550 C.C FROM 2500 RPM WHEN OVER 12 PSI

 

Raise the injection rpm up. You are quenching the cylinders espically with 80% water. I would raise it to 3500rpm and 50/50 mix.

 

Have you verified TDC on your balancer lines up with real TDC?

 

yes!! its o.k