Hughes FI Airgap Install Thread
Champion
Joined: Oct 2009
Posts: 4,717
Likes: 10
From: N/A
Best as I can, not all 24lbs injectors flow the same cc's, cc's is a more precise way to read what the injector is delivering for fuel. For most an injector upgrade is not needed if you use a tuner, I changed injectors because I had a lean spot mid range and do not use a tuner. Stock injectors are good to 450+hp if a tuner is used. I was into this many years ago I still have some info on this but Drewa is the man when it comes to injectors for these trucks
Record Breaker
Joined: Sep 2012
Posts: 2,437
Likes: 73
From: S. Florida
This would be true is you look at "24lb injector" as a generic size.
A 24lb injector could conceivably be anything between 23.5lbs/hr and 24.5lbs/hr (a 10.5cc/min range).
When tested injectors are noted to 1 or 2 decimal places of a lb/hr... 0.1lb/hr is about 1cc/min, so the accuracy of using imperial or metric notation is in the same ballpark.
And since the ECM is capable of allowing for a range of injector flow rate (though all 8 should be matched), the difference between an injector selected by either imperial or metric designation is insignificant as far as the ECM is concerned.
A 24lb injector could conceivably be anything between 23.5lbs/hr and 24.5lbs/hr (a 10.5cc/min range).
When tested injectors are noted to 1 or 2 decimal places of a lb/hr... 0.1lb/hr is about 1cc/min, so the accuracy of using imperial or metric notation is in the same ballpark.
And since the ECM is capable of allowing for a range of injector flow rate (though all 8 should be matched), the difference between an injector selected by either imperial or metric designation is insignificant as far as the ECM is concerned.
Record Breaker
Joined: Sep 2012
Posts: 2,437
Likes: 73
From: S. Florida
As an update to my earlier post (post #9);
I just recently got the LT's and 3" exhaust fitted (without cat, as there wasn't room).
The new exhaust system has improved the lower RPM acceleration that was in question with the intake install.
This improvement also carries through the higher RPM ranges as well, so over 2000 RPM it's really coming together nicely for a little engine.
After a couple of tanks to see how the MPG's are going, I'll up the octane and tune to 97 and see how that goes.
I just recently got the LT's and 3" exhaust fitted (without cat, as there wasn't room).
The new exhaust system has improved the lower RPM acceleration that was in question with the intake install.
This improvement also carries through the higher RPM ranges as well, so over 2000 RPM it's really coming together nicely for a little engine.
After a couple of tanks to see how the MPG's are going, I'll up the octane and tune to 97 and see how that goes.
Administrator
Joined: Apr 2010
Posts: 87,404
Likes: 4,214
From: Clayton MI
Only real problem is what to do with the fuel crossover hose at the back of the fuel rails. Injectors are closer together on the airgap, so, that tube needs to be shorter. Kit should come with the right stuff, though, some have not had luck with the hard plastic tubing, and just gotten fuel injection hose, and hoseclamps instead. Aside from that, pretty straightforward. Be sure and use NEW intake bolts.....
Administrator
Joined: Apr 2010
Posts: 87,404
Likes: 4,214
From: Clayton MI
Does the manifold have provision for EGR valve? That's the only real problem I could see, and from past history, it doesn't really seem to be that much of an issue. The PCM may or may not whine about the lack of EGR......