So I am currently rebuilding my engine. I have a PFC with out commander and 1300cc injectors I plan on installing. This thing is, I want to run the car on the stock ecu while I break it in, but I want to install the 1300cc's now while the engine is out. My question is, can the stock ecu run the car properly with the 1300cc injectors installed? constructive criticism welcome

 

nope, it will run very rich as it thinks it still hss 850's.

 

only if he goes into boost.

it will be fine Preston if you keep a low profile on your foot above 3500 RPMs. the secondaries will only kick on after 3500 with a moderate amount of load. you can also simply just avoid going past 3500 RPMs altogether which eliminates the possibility of the secondaries coming on completely and dumping a ton of raw fuel down it's throat.

 

thanks Ben, I can always set my mbc to not produce any boost right? I will be very light on the throttle anyways cause I'll be breaking it in. what are the consequences of it dumping too much fuel if I accidentally over do it?

 

the boost can't go any lower than the spring pressure of the wastegate.

 

well you'll be about 25% richer(rough guess because i don't feel like getting a real figure) once the secondaries do come on, which will mainly just result in some carbon deposits and poor fuel mileage if you do it often. you can't really avoid all boost with the wastegate but you can vent the intercooler piping to atmosphere so boost is dumped with some small filters where the stock blow off valves reside or place an air filter onto the end of your intake elbow to the throttle body and just plumb the turbos to keep dirt and crap out of them until they're needed again.

in all honesty, even with the large secondaries it won't kill it if you do accidentally go into them here or there for short periods of time. if it were me i'd just run it and try to avoid getting on it until the break in is complete.

 

Great that you Ben, once again and others for your help!

 

You would be better off breaking the engine in on the base map.

Attempting to run the car without using the secondaries is a much much worse idea.

 

Base map or stock ecu doesn't matter. Either will be fine as long as you don't get on it.

 

I have been using the patented Granny-Acceleration method myself for the past month, oh how i hate you Mr. break in period.

 

Great thanks guys, And I thought I'd be getting flamed haha

 

basically you're saying to run the car with the stock ECU then, because the stock base map is very similar to the stock ECU mapping. it would still run pig rich once the secondaries stage on. the one benefit of using the pfc though is setting the RPM limiter which can help keep it out of that staging point as well as a lower boost cut in case the throttle sticks.

 

If you run the default PFC fuel map, which I assume is probably similar to the stock ECU fuel map, wouldn't you still be better off with the PFC because you can set the secondary injector size to 1300cc.? Which would mean that the pulses would shorter and you wouldn't be running richer.

 

I'm pretty sure he meant to load the base map onto the PFC

 

setting the injector size figure in the PFC is just a placesetter so that future tuners know the size of injectors that are fitted to the vehicle, it changes nothing to fuel and still requires tuning.

many people wouldn't require retuning after changing injectors if that was the simple case. you can of course map it all out manually with a conversion table, assuming the injectors are producing their rated outputs.

 

While your car is running, change the primaries from 550cc to something else like 850, with the % correction like you should be doing anyways, even if you dont touch lag times, it will run like ****.

I agree, it will require tuning still, but setting the correct injector sizes makes it run more proper.

 

Since he doesn't have the commander, he won't be changing the injector settings.

 

I was going to do that too.Changing my stock 850cc injector to 1300 cc I got PFC and commander car was tuned also now can i change to 1300 cc injector with out re tune it? I see on the commander that you can just change the injector size.

 

Unfortunately yes... I'll be getting a data logit as soon as im ready to tune, that is why I bought one with out the commander.

 

Actually now would be a good time to get your datalogit---you can create a "breaking in map" with low rev limit,slow boost build etc

 

You will need a new tune. A friend of mine didn't re-tune after new injectors, and blew his motor. His car's tune was done by Steve Kan. It didn't protect the engine with bigger injectors.

 

My question to you is: why did you put yourself in this situation?

 

put the pfc in and set the rev limiter to 4k rpm