Hi,

So i sent out my 1300cc injectors to get cleaned and tested at witchhunter and i just got them back.

the flow test showed that they flowed 1480 and 1500.

am i able to just change the injector size and lag time to 1500 for them? to drive around for now or do i just leave it at 1300 with my previous tune?

Thanks

 

That is a big difference from 1300. Where did you get them from?

If you had previously tune your car with them setup as 1300 and now change it to 1500, you will have to AFR tune the whole area of the map where the secondaries work.

 

they were from rc eng originally

i just need the car to be able to drive around till i get it retuned, just wondering if i should set the datalogit to 1500 since that was what the flow test showed.

 

If you have a way to read your AFR's, then I would just put them in and leave it set at 1300 and see how it is. Leaving them at 1300 if they actually flow 1500 will only make the car run rich where the secondaries are on.

 

I deal with A LOT of injectors and have seen this before. They most likely are 1300cc injectors. Look at the pressure at which they were flowed at. At a higher pressure they will flow more...

 

ok so i just stuck them in as 1300s for now, and the car is running just fine

not like i really drive where the secondaries come on right now so should be good tilli i get a retune.

it got tested at 43.5psi or so

 

I think it was Keith from KG Parts who was mentioning in some post somewhere that Denso injectors (which are stock on FD's and many other Japanese cars) actually were designed to have their rated flow at 2.25 bar (~32 psi) whereas a lot of other brands of injectors are rated at 3 bar (43.5). That's why Denso injectors have a reputation for flowing more than other brands.

 

I can add another data point. I recently had a pair of RC modified injectors purchased through SR Motorsports at least 6 years ago cleaned and tested by WitchHunter. Theya re stock Denso 850's bored out to 1300. Both flowed well in excess of 1400. I don't have exact specs but IIRC 1430 and 1450. Car ran well with PFC set to 1300cc injectors but my fuel maps were always set "leaner" than many others I know. I self tuned the maps using WBO2.

Interesting info regarding Denso's flowing more than other brands.

I plan on continuing to keep the setting at 1300cc and tune maps accordingly. At least know I know why my maps are "leaner."

Regards,
Crispy

 

In the end it does not matter. If you tune the injectors correctly for idle, cruise, boost transistion, and full boost the car will run great. The only difference will be the DUTY CYCLE that the PFC calculates and the DL records. Most do not care/worry about that unless it goes over about 90%.

Take using 850 primaries and having to use negative lag to lean out for idle.
Let's say that reduces idle fuel flow by 2ms. When on boost 2ms more flow in trhe map will correct that decrease. It all works in the end.