Info: bigger injectors: what are they like @ idle?

[Hot COCOAL]

I've read bunch and must have just stumbled past this question or its not been covered(which i doubt)
And i do not intend to start a shit storm about tuning/tuners, or injector company pissing matches.
I know there is a whole lot more to it than just bigger holes and more fuel(quality of the holes and tuning and what not) anyone want to throw down a lecture on tuning, be my guest.

What i was hoping to get insight into was, what effect more flow(bigger holes dual cp3 etc.) would have to the exhaust stream @ idle? I've heard it gets pretty raw smelling once you get up past +30% or 28lpm. Having no experience with with aftermarket injectors i am relying on the forum here for my knowledge.

So what have you guys/gals experienced? Any obnoxious emissions at idle with big tips/injecrors, i mean at what point is too big to sit in traffic with for a DD truck?

 

[DBUSHLB7]

60 overs for me cocopuff. Robs tunes. Run #3 tune on DSP 5 setup for DDing and its fairly good as far as low smoke goes. #4 and 5 will lay down Prius repellant. Any more now, 100 overs are becoming street able these days.

 

[delong_1]

I had 100% overs and never had idle smoke even here at 5600'elevation. I had a really tough time with part throttle smoke and now I'm down to approx 35% nozzles from ddp and I guarantee the will make at least 900 hp here so that's all I really need. No raw fuel smell, low smoke at idle and part throttle.

 

[DBUSHLB7]

I was unloading a few things out of the truck bed the other day while the truck was running and now that you guys mention it, it did smell pretty strong....but NO smoke @ idle.

 

[08liftedHD]

Mine used to be worse until my tuner figured out how to raise RP to above 7500psi at idle. Still see smoke in headlights at night but that's it.

 

[DAVe3283]

60% overs on my LB7. Smells like diesel (think GM 6.2L smell) with 40 MPa rail, but idles nice and quiet. Visible haze in the right light (headlights/dusk). If I bump the rail to 60 MPa, smell and haze are totally gone, but engine sounds more like a diesel than stock, but not bad. Flipping between the pressures on the DSP2, you know the difference, but I doubt anyone would notice it being "loud" without hearing them back to back.

 

[adeso]

I bet my #3 tune with 60s smoke as much as a clean #3 tune on stock sticks, can't tell it isn't 100% stock unless you romp on it. They do make some more noise at some RPMs thats it

 

[Great White]

I have a DSP 5, Stock Injectors with one stock cp3, tunes by Rob at ATP. DD on level 4 at idle generates a fair amount of noticable smoking which cleans up as soon as I get moving and the turbo spools a little. If I try to pull a little too quickly off a dead stop or before the turbo is pulling firmly it will, as DBUSHLB7 stated lay down "Prius Repellant" for a moment definitly noticable. Our altitude here in Show Low Arizona is about 6300 Ft+.

 

[Harbin_22]

My dipper 40% stink at idle unless the rp is raised to about 45mpa. Got some 60% from MFE(Diesel USA group) that will be in next week, I'll report back with re sults.

 

[Harbin_22]

I have a DSP 5, Stock Injectors with one stock cp3, tunes by Rob at ATP. DD on level 4 at idle generates a fair amount of noticable smoking which cleans up as soon as I get moving and the turbo spools a little. If I try to pull a little too quickly off a dead stop or before the turbo is pulling firmly it will, as DBUSHLB7 stated lay down "Prius Repellant" for a moment definitly noticable. Our altitude here in Show Low Arizona is about 6300 Ft+.

Sounds to me that your injectors are going bad. Stock should not smoke at idle, usually smoke at idle on lb7 is symptoms of bad injectors.

 

[Hot COCOAL]

I was unloading a few things out of the truck bed the other day while the truck was running and now that you guys mention it, it did smell pretty strong....but NO smoke @ idle.

This is what i am wondering.
My wife(especially) and a few others noticed right away when the egr went "missing" so i am curious as to what is a good size/hesitant to buy/concerned to go too big with the injector, but also don't want to feel like i coulda had more.
My injectors are on the tail end, my engine is still stock, my goals are for 800+whp in the future and i would like to only buy injectors once(for the foreseeable future)
At first I was wanting to go with 60% over injectors(38lpm?) But now im wondering if 40%(32 lpm) or even 30% (28 lpm) will be sufficient. I dont want my truck to have a "unburnt, raw, hit your nostril and make your eyes water"...
SMELL.

Thanks to all for sharing your experience!:hug:

 

[Hot COCOAL]

I had 100% overs and never had idle smoke even here at 5600'elevation. I had a really tough time with part throttle smoke and now I'm down to approx 35% nozzles from ddp and I guarantee the will make at least 900 hp here so that's all I really need. No raw fuel smell, low smoke at idle and part throttle.

Thanks, nice info to have, I'm really starting to think i want to go as small as possible, whereas before i wanted to go as big as possible. I think 30-40% should be more than enough for my goals, with info like this coming out i feel better going smaller

 

[ChevyDieselLLY]

I have 100 overs and on my #2 tune which I dd on you can smell some fuel. If I idle in the driveway for to long my wife has told me she can smell it in the house. Lower rpm going up a hill here it wil start to smoke.

 

[PACougar]

Jason, I've made over 900HP at the wheels on my 60 overs and I have a lot of fuel left for more power, if your goal is 800's I would say don't go bigger than 40 overs for any reason. I have had a small bit of smoke at idle from time to time, but it isn't very noticeable.

 

[whitelmmmax]

100 overs here no smoke at idle, and never really noticed a smell. I dd on level 3 and hardly any smoke at half throttle. Tranny tuning plays a big part in it. IMO

 

[S Phinney]

Almost all over sized smell at idle. The bigger you go the more little things you will notice. Stay at 45 overs.

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[adeso]

It is a balance, mine smell just a little bit but no smoke-but smaller sticks will mean more EGTs if you push them hard (longer uS means more EGTs). If it was my truck I wouldn't want to do many 800HP runs on 45 overs, but that is just me (and yes you can make that power on them). You need to figure out if you care more about the smell or making fast passes at the track while keeping the engine living

 

[DAVe3283]

It is a balance, ...

Exactly. And you don't necessarily need to live with a smell with bigger injectors either. Play with the timing and fuel pressure at idle, and you can get rid of the smell entirely. However, it will sound a little louder at idle. It is all what is important to you.

That is why I have the DSP set up. I have a DD tune that is quiet but smells a bit. I use that most of the time, and at drivethroughs. The other tune is a hair louder, but no smell. I use that if I am in a barn/shop/garage, or if I will be downwind of the truck for a while.


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[adeso]

I just got used to the noise, after I spend a month wondering WTF I did wrong with the build trying to track it down

 

[ecc_33]

I wouldn't go any smaller than a 60% bigger injector. Mine drive and idle fine on my "big" tune. Very little smoke accelerating at half throttle. Its all in the tuning dude.