KATOOM

Will installing larger injectors have an effect on performance, good or bad, at higher altitudes? Does it cause any loading of the engine at idle. I'm talking no bigger than DD2's either. I could see were really big injectors could be a draw back for some situations. Thanks for any info.

Push Rod

The higher you go, the smaller the injector you need to keep things streetable, vis a vis smoke control. As for power, the bigger injector will still make more power, until you have so much fuel that you are quenching the fire in the cylinder. DD2s will work fine at your altitude, or if you want to push things, try out a set of bigger EDMs. We use Don Morrison's EDMs around here, and find that they work very well.

Rod

XLR8ER

how high is high, i curious because i'm just starting out on mine and live at 7000'. it was suggested to me to not worry about injectors but to go with a plate,gsk & 16cm housing and wheel,

Push Rod

We don't have a pile of experience around here with high altitude running, as we're sea level flat-landers We have been able to generate some rules of thumb (although their are exceptions to every rule):

Up to 1500 ft - Don't worry about it.

1500 - 3500 - With extrude hones, we've seen that an 80 HP injector will smoke like a 100 HP injector at sea level while making about 10% less pony

3500 - 5500 - 15% less HP (approx, with some wide variations) and more smoke. I personally wouldn't run more than a 100 HP extrude injector at these elevations, or maybe a 120 HP EDMed injector.

Past 5500 - No idea on the pony level, but I _really_ don't like seeing more than a 80 HP extrude, or 100 HP EDM at these elevations. We've got a couple customers who often visit 10K elevations for their work, and we weren't all that comfortable with more than an RV275.

Now, I'm talking 24 valve injectors, and don't have enough experience with 12s at elevation, although I think the advice of sticking with the plate and GSK is sound, especially with your 97 215 HP truck. The RV230/M300s don't give you enough HP boost above the stocker injectors to make them worthwhile and the 370s would simply be too much above 3500 ft.

Rod

StakeMan

Someday I will get to lower altitude to compare the difference. As of now, my truck has never been much below 5000 feet.

It comes down to compromise.

How much smoke are you willing to have?
How much lag?
How much EGT?

XLR8ER

smoke doesnt bother me, right now lag doesnt bother me (it's not used for racing just pulling). egt? just below melt down? it runs at 1100 now under heavy loads wot. and i dont have anything done yet? sorta!

KATOOM

Thanks for the replys and good info Rod. I assume this means you would still have more power than stock or could you lower power by installing larger injectors in high altitudes? Would I just be getting a bunch of smoke but still more power? I guess the main point of the question is, would stock injectors be beneficial if you drive in the mountains or will larger ones give you more power (with more smoke) and resulting in any strange engine characteristics.