LMM: Injector size

[CRAWLEN]

Having a bit of an issue working out what injector size i need for the lmm im building.
my plans are i want to be capable of 700hp possibly more in the future but also have a low power turn say 500hp on a dsp5 switch.
i dont want it to be a soot machine and for it to drive and run nice.




turbo i will be running with be a 68mm stg2r from danville.
will also have a 10mm cp3.


been told 100% overs by lds, is this going to be a good size ? any suggestions are much appreciated

 

[Ne-max]

100s are about the perfect size

 

[KRODMAX/KS]

45's will get you there with ease, i am in that range and over but wish I would have gone with at least 100's. More room to grow.

 

[JoshH]

Agree with everyone, 100s are a good size for you.

 

[CRAWLEN]

Cheers thanks for that guys, was just worried the 100's might of been a bit big and pain to tune down for lower power. but seems like i have nothing to worry about

 

[N2BRK]

your goals for hp and low smoke could be done with the larger cp3 and stock or slightly larger injectors. Unless you're going to build the engine at some point, I wouldn't go 100 overs. As a street-driven truck in NJ... my 40 overs are dirty enough down low, IMHO.

 

[zakkb787]

your goals for hp and low smoke could be done with the larger cp3 and stock or slightly larger injectors. Unless you're going to build the engine at some point, I wouldn't go 100 overs. As a street-driven truck in NJ... my 40 overs are dirty enough down low, IMHO.

Sounds like you need some new tuning... no reason 40s should be dirty

 

[N2BRK]

LMFAO:roflmao:

 

[Chevy1925]

your goals for hp and low smoke could be done with the larger cp3 and stock or slightly larger injectors. Unless you're going to build the engine at some point, I wouldn't go 100 overs. As a street-driven truck in NJ... my 40 overs are dirty enough down low, IMHO.

I daily and tow with LLY 100 overs. They are cleaner and tuned better than the 45% over LB7 injectors I had.

If you can’t make injectors at or under 100% clean up, you have tuning issues or a mechanical issue or it will be inherent due to the engine build. A good haze when cold at first start up for 100% overs is common and slight haze down the road can happen but being dirty down low has to do with tune, turbos, and engine build

 

[zakkb787]

LMFAO:roflmao:

Laugh all day big guy. Not hurting my feelings. Lots of people running clean 100+ overs :thumb:

 

[N2BRK]

I daily and tow with LLY 100 overs. They are cleaner and tuned better than the 45% over LB7 injectors I had.

If you can’t make injectors at or under 100% clean up, you have tuning issues or a mechanical issue or it will be inherent due to the engine build. A good haze when cold at first start up for 100% overs is common and slight haze down the road can happen but being dirty down low has to do with tune, turbos, and engine build

James - you know that to light the stg2r (or any turbo larger than stock), she will give a decent puff and then she cleans up with boost right away. If you are in a situation where you lean in with no downshift and low RPM shes going to be dirty unless you unless you throttle it more to get it to downshift, etc. It doesn't matter if you have 40 overs or 100 overs... you need the same quantity of fuel to get the responsiveness out of the turbo. Since Mark is making 650hp on that turbo with stock injectors and a 12mm cp3, 100 overs on a daily seems a bit excessive to me... unless you have plans to build the engine.

If you have a smaller turbo or aren't looking for the fastest spool, then you can be cleaner but who wants that I didn't set my truck up to be lazy. But as soon as you mention any soot output at all, people jump on tuning right away. If you want zero smoke, then put your DPF back on :roflmao:

 

[Ne-max]

LMM 100 overs flow less then any previous year 100% Over.

 

[gmduramax]

James - you know that to light the stg2r (or any turbo larger than stock), she will give a decent puff and then she cleans up with boost right away. If you are in a situation where you lean in with no downshift and low RPM shes going to be dirty unless you unless you throttle it more to get it to downshift, etc. It doesn't matter if you have 40 overs or 100 overs... you need the same quantity of fuel to get the responsiveness out of the turbo. Since Mark is making 650hp on that turbo with stock injectors and a 12mm cp3, 100 overs on a daily seems a bit excessive to me... unless you have plans to build the engine.

If you have a smaller turbo or aren't looking for the fastest spool, then you can be cleaner but who wants that I didn't set my truck up to be lazy. But as soon as you mention any soot output at all, people jump on tuning right away. If you want zero smoke, then put your DPF back on :roflmao:

I daily drive 250’s with an 80mm single. My truck is not lazy and it’s clean must be the good fuel I run :coolspot:

 

[CRAWLEN]

To the comment about building the engine it's already being built few of the guys know this. When I said I dont want it to be a soot machine. I didnt mean I want it super clean l, I just don't want it constantly pouring out smoke, yeah I love rolling coal but there is a limit. And no dpf isnt going on this as the engine is not going in a Silverado its being used for an engine swap.


Cheers for the useful helps guys I will stick to buying the 100% overs

 

[WolfLMM]

Seriously, if you want no smoke output go with 45s.

100s would be a good fit, but they will be a tad Smokey.

I agree with n2brk, use pressure to get your fuel quanity, 700hp is easy for 45s with good injection pressure.

Jmo

 

[WolfLMM]

To the comment about building the engine it's already being built few of the guys know this. When I said I dont want it to be a soot machine. I didnt mean I want it super clean l, I just don't want it constantly pouring out smoke, yeah I love rolling coal but there is a limit. And no dpf isnt going on this as the engine is not going in a Silverado its being used for an engine swap.


Cheers for the useful helps guys I will stick to buying the 100% overs

Should have read this first lol, 100s will be great then!

 

[N2BRK]

laggy and dirty are very subjective. Since my wonderful state has a $5000 fine for intentionally rolling coal, I am paranoid that a little poof as I pass a car will make a local LEO giddy to pop his $5k fine cherry... so I may say something is a dirty and others might think it's "clean" :thumb:

 

[SickLL7Crenshaw]

100s without a doubt. Can be tuned to be just as clean as stock. Guaranteed.

 

[Chevy1925]

James - you know that to light the stg2r (or any turbo larger than stock), she will give a decent puff and then she cleans up with boost right away. If you are in a situation where you lean in with no downshift and low RPM shes going to be dirty unless you unless you throttle it more to get it to downshift, etc. It doesn't matter if you have 40 overs or 100 overs... you need the same quantity of fuel to get the responsiveness out of the turbo. Since Mark is making 650hp on that turbo with stock injectors and a 12mm cp3, 100 overs on a daily seems a bit excessive to me... unless you have plans to build the engine.



If you have a smaller turbo or aren't looking for the fastest spool, then you can be cleaner but who wants that I didn't set my truck up to be lazy. But as soon as you mention any soot output at all, people jump on tuning right away. If you want zero smoke, then put your DPF back on :roflmao:

You can lean into a 68 stg2r with 40s or bigger and keep it clean without a downshift. Been in a few trucks that Steve setup that way. Some of the best driving ones I’ve been in with that turbo. But again, it comes down to a factor of things if you want that. Some people don’t believe it and that’s fine, I know it can be done as well as those that currently have the setup. I know chaves91 has done the same as well

Quantity of fuel to light a turbo does not mean it’s the same across the board for 100s or 40s. The duration makes a big difference here as well as timing. Pilot injection also comes into affect and so does maf. It can vary greatly

 

[Ne-max]

You can lean into a 68 stg2r with 40s or bigger and keep it clean without a downshift. Been in a few trucks that Steve setup that way. Some of the best driving ones I’ve been in with that turbo. But again, it comes down to a factor of things if you want that. Some people don’t believe it and that’s fine, I know it can be done as well as those that currently have the setup. I know chaves91 has done the same as well

Quantity of fuel to light a turbo does not mean it’s the same across the board for 100s or 40s. The duration makes a big difference here as well as timing. Pilot injection also comes into affect and so does maf. It can vary greatly

Also proper converter has a lot to do with it.