Troublezilla

Can someone help me out by explaining the difference between the injectors in an HO vs. injectors for a SO. If the two engines have different injectors from the factory, how will they enterchange. I am considering an upgrade, but I do not won't to over due it. Maybe 300's or F1 1's. And are the 300's EDM's or 7 holes. Thanks for the input.

Don M

The HO injectors are smaller ( flow rate ) than the SO injectors. I measure the SO at 26 and the HO at 22. The 275/300's are larger yet, measured at a 34. All of these are 7 spray holes. Of course the higher the flow rate...the higher power level when speaking of stock injectors of the same design.

The Mach 1's are a lot smaller than most think. They have 8 spray holes. The first 8 hole injectors ever for the Cummins ISB engines. After testing everything under the sun from 5 holes to 21. We settled on 8 as the best overall number for that power level and design.

Don~

BigBlue

The 300's aka 275's are factory bosch injectors that they put into their motorhome engines. Same engine as ours, just different injectors and computer. As far as I know, the injectors are the same on the HO and SO. The difference is in the injection pump. The HO has higher pressures, but less volume where as the SO has lower pressures but higher volume. After about 500 or so hp, the HO pump signs off. HO's respond very well to injector upgrades and the SO's respond very well to computer upgrades (comp, TST, etc.).

BigBlue

I stand corrected by the injector god. There is a difference.

Troublezilla

Thanks for the clarificaition. So say with a quadzilla 70hp chip and 300's would be a nice mild upgrade?

BigBlue

That would be really nice. Smooth power, nice EGT's, and not to hard on the drivetrain.

Troublezilla

So, this is where the HO gets 20 or so more HP out of the same injector is because it had a smaller injector to start with. Right......or not.

Troublezilla

Hey Don,
If you read this how much HP will your stage ones actually add to a HO engine.

Don M

Yes, the SO injectors when used in the SO will add some HP. Probably between 15-25.

The Mach 1's will add about 75. Cleanly. As clean as a RV injector.

Don~

Troublezilla

Anybody got any Mach 1's that they have outgrown? I am broker than last summers.