I'm getting ready to order an RTek 2.1 and four new injectors. I like the idea of 720s with my S5 streetport (87 TII), given the mild build of the car (see below) and the fact the ECU can compensate for 720s. My problem is, I'm having a hard time turning away the price of the 750cc injectors from RCEngineering. I'm looking at about a $120 price difference, plus the fact they flow more fuel and come highly reccomended vs. the only 720 I can find, a Greddy labeled part.

Question is, can I use 750s with the 750 base map to get me going, fairly safe? What would be the problems?

The car is an 87TII with a street ported engine - no miles (direct from Atkins), 3" turbo back

The only forseeable change I'll be making in the near future would be a FMIC.

Help me spend more money!

 

The difference between 720 and 750 is negligible and could easily be 'fixed' with tuning. With no correction, it will be a tad richer, nothing dangerous. You just want to be sure you end up with high impedance. (i.e. you put resistors in series if the injectors are low impedance)

 

The idea of larger injectors also attracts me. But I do not know anything about tuning how adjusting the map? He occasionally Excel map to different injection I looked at the differences? Thanks

 

This makes sense. I have the 87 TII, with the injector resistor box still. I'm going to leave it in and just go with a drop in injector. That make sense?

 

^ If the RC 750s are low impendence (almost all aftermarket injectors are), then yes, they will drop right in and work properly.