New cam and higher # injectors?

[Matahoe]

I'm in the process of replacing my cam. I also taking this opportunity to ultrasonic clean the right side bank of stock injectors on my LM7 engine. I got the cam stuff down pretty well (it's an Elgin step up mild cam). I didn't want a funny idle or a higher rpm torque band that requires a new intake, valve springs, programming, etc. I also already did the driver's side injectors 2 years ago. I noticed a marked difference in better idle and power btw. Before I go any further does it make sense to upgrade to a higher pound injectors even though I'm stock? Or would it be a waste? Do any types of tunes require the higher pound ones? That is of course I decide to supercharge or turbo it. That's a ways away for me. looking for opinions. Thanks.

 

[kbit]

Your injectors are fine, don't mess with them unless/until you turbo or supercharge it. With a super mild cam you'll be fine where you are.

 

[strutaeng]

Yeah, for stock (or stock-ish/mild cam) absolutely no need for higher flowing injectors.

I swapped an L59 into my 99 Silverado with a base LM7 tune. The higher flowing injectors (flex fuel) always ran around 11% rich on the fuel trims, but still ran fine. I finally motivated myself to figure out how to correct the injector flowrate on HP Tuners last fall which wasn't even that difficult TBH.

 

[Matahoe]

Ok. So let's say I want to use E85. I would obviously need higher pound injectors like you have. Can you change fuel tables on the fly with HP tuners since my vehicle has no fuel type sensor in it? Or I could just grab a junkyard PCM which had E85 and reprogram the VIN to my vehicle?

 

[rockola1971]

Ok. So let's say I want to use E85. I would obviously need higher pound injectors like you have. Can you change fuel tables on the fly with HP tuners since my vehicle has no fuel type sensor in it? Or I could just grab a junkyard PCM which had E85 and reprogram the VIN to my vehicle?

Your current fuel system is not setup for ethanol which is highly corrosive. You also do not have the octane sensor in your tank.

 

[Matahoe]

The fuel tank and lines are similar for both. Common misconception. Already looked into that. If they weren't you wouldn't be able to use E10 or E15 either. Which many do. But yeah the only difference is the PCM programming, injectors and added fuel type sensor and harness. Hence my question. I have ran E85 multiple times with no adverse effects aside from the SES light coming on for lean condition.

 

[strutaeng]

Ok. So let's say I want to use E85. I would obviously need higher pound injectors like you have. Can you change fuel tables on the fly with HP tuners since my vehicle has no fuel type sensor in it? Or I could just grab a junkyard PCM which had E85 and reprogram the VIN to my vehicle?

I'm assuming you are talking to me?

Fuel tables? I think those are the "VE tables"?

I'm my case, I didn't change that. There's an input for injector flowrate on the program. I went from 33 lb/hr to 25 lb/hr IIRC. Then just re-wrote the tune. I'm not an HP Tuners expert BTW. I can download, save and make minor adjustments like VATS delete and gear ratio changes. "Tooning" is kinda a separate subject, in itself.

If you want to make changes easier, you can look into the Holey ECUs. I forget their names, Dominator and something like that. A lot easier to make changes via the little touchscreen it comes with. But I don't know anything about them TBH.

Also, when you get into cam swapping, you will need a "tune", especially when it comes to the more radical profiles.

 

[Matahoe]

Ok. Good info. Not that big of a deal as far as modding goes. Just staying close to stock with no need for anything else like Holley has to offer. I wish I could mess around with aftermarket stuff like that. Lol. Thinking about getting HP tuners software is about as extreme as I can get atm.

I will delve into the tuning required. It's not a big change in lobe separation or lift. Guess I can email Elgin to see what they say. Probably should've been my first option but I appreciate everyone's input on this forum. Thanks.