MicroSquirt.com read only forum (Jan.15,2018)

Hi,

I used Bosch 0 280 150 702 injectors with flow rate 18 lb/hrs (189 cc/min) on my car ( FIAT 1.4 engine, 4 cyl. N/A) and had Idle PW of 2.1 ms (when cruising goes sometimes as low as 1.8 ms)

Now after mounting intake trumpets and mounting cold air box, set of injectors 0 280 150 152 which flow 22.5 lb/hrs (237 cc/min) low impendance (have original resistor pack) would be physically better match.

The calculation shows that for 18 lb injectors, Idle PW=2,08 ms (My datalog shows 2,1 ms) which is OK.
For injectors 22.5 lb calculated Idle PulseWidth=1,88 ms

Now that is pretty close to that recommended limit of 1.7 ms

Shall I go for it ? Can someone please share their experience with big injectors?

I use MSnS-extra 29q ,board V2.2

Regards, Drazen

I`d have a go and see how well you can get it to idle, I went from 22lb to 42lb injectors on my 1.8 16v and the idle`s fine (2.2ms approx when hot, 14:1 afr).

If you`re prepared to spend 15 mins to tune the idle for the new injectors give it a go.

Hi,
thanks for response.
Unfortunately, those injectors are not interchangable, they differ in shape, lenght and fuel rail shape ( the first are with o-rings, the second are barbed).
Since I had to do some fabrication to mount either set on my new ITBs I decided to go with my old injectors- they have been proven after all. Even they are quite big for this small engine, and 2.1 ms warm idle PW seems just about low enough.
Thanks, Drazen

If the 237's are a bit big then turn your fuel pressure down a bit - no biggie at all.

Are you running more than one squirt? If so, turn the number of squirts down.

Todd