Has anyone had a problem with running enlarged injectors while road racing?

Prior to installing the larger injectors, I had the stock 850cc secondaries and it ran fine and had good power- on and off the track. They were at 95% duty cycle though so I installed a set of 1200cc's and changed the PFC injector settings to reflect that. It runs fine on the street, good idle, great power. But when I get on the track and push the car hard with the 1200cc injectors I loose a bunch of power and see puffs of black smoke coming from the exhaust. That indicates an overly rich condition, so I think the secondaries are going to 100% duty cycle or very close to it. The PFC however only shows 75% at the most.

I took the injectors back to RC Engineering to re-check them. Of course they worked fine.

Since everything worked with the 850cc's I suspect its the 1200cc injectors, not the PFC.

Anyone?

 

First, it will not make the difference you need by just changing the # to 1200 in the PFC commander. Your base map needs to be adjusted also; tuned.

Second, I've heard that RC injectors suck for these cars.

 

It works close enough; I know it needs to be tuned to be right on again.

They aren't RC injectors, they don't even sell these. They will only take ones you supply and enlarge them.

 

I believe RC does sell injectors for our cars.

So which injectors did you have enlarged? Your stock 850 cc ones? That might be an issue.

 

you put 1200 for the secondaries but what did you put in for your lag time?

 

I asked, and RC doesn't sell side feed injectors, they will only enlarge ones you supply them.

For various reasons I bought new 550's and had them enlarged.

Since 550's were in the secondary position I modified the lag times to reflect the lag times of a 550 injector. Hardly any adjustment at all- less than 0.1ms. And RC claims enlarging them doesn't effect the open/close times.

 

Don't know if its a typo, but 850 cc are the secondary, not 550cc. Just a thought. Although if they are flowing what a 1200 cc injector is supposed to flow, is doesn't matter if it started as a 550 or an 850 but some have trouble with RC injectors not flowing to well (850 to 1200), spray pattern, dibbling, etc.

Tim Benton