Which injector should I go with?

Gearhead · Sep 11, 2011

Why not 175 with 100% nozzle since they will run EXACTLY the same as the 155 with 100% when running a tow file from someone who knows what they are doing?

strokin6L · Sep 11, 2011

Matt, with talking from guys in my area who have 155's, 175's and 190's...the 155's run cooler egt's with a tow file than the guy with the 175's with a tow file while towing the exact same weight. Maybe the difference is just in the tuning...IDK, but the 175cc injector with a tow file should flow more fuel than a 155cc injector with a tow file. If not then what's the point of an injector builder building 175cc injectors then? I know the 155 with powermax combo has been a proven towing setup. And with towing a weight of 25K lbs....i just see no reason to go any higher than a 155cc injector. Especially if it's a truck that tows that weight alot.

Chris · Sep 11, 2011

It really depends about nozzle size more than anything else. A 190/75 is more driveable than a 155/100, all things the same. Like matt said with correct tuning the 175/75 would be the better choice, plus you can have more power on tap when youre not towing.

In a towing or cruising situation, i highly doubt youre running 2.5 ms of pw, so at that point the 155 or the 175 woudl make no difference.

The reason a 155 may run cooler towing is it MOST LIKELY doesnt have a 100 percent nozzle. Where as a lot of 175s might. This would be a VERY good reason for the 155 to run cooler.

Another thing to consider is turbo choice. What are you power goals? Honestly, if youre not going over 500, i say stick w/ a stock turbo. The powermax imo is really not that much greater than s tock turbo. It does have its place, but it doesnt belong on a truck that tows a LOT and wont be going over 500 hp anyways.

strokin6L · Sep 11, 2011

matt didn't say 175/75 tho...he said 175/100 nozzle

strokin6L · Sep 11, 2011

Chris said:
It really depends about nozzle size more than anything else. A 190/75 is more driveable than a 155/100, all things the same. Like matt said with correct tuning the 175/75 would be the better choice, plus you can have more power on tap when youre not towing.

In a towing or cruising situation, i highly doubt youre running 2.5 ms of pw, so at that point the 155 or the 175 woudl make no difference.

The reason a 155 may run cooler towing is it MOST LIKELY doesnt have a 100 percent nozzle. Where as a lot of 175s might. This would be a VERY good reason for the 155 to run cooler. Another thing to consider is turbo choice. What are you power goals? Honestly, if youre not going over 500, i say stick w/ a stock turbo. The powermax imo is really not that much greater than s tock turbo. It does have its place, but it doesnt belong on a truck that tows a LOT and wont be going over 500 hp anyways.

the guys trucks that have those injector sizes....all have 100% nozzles

SIX_OHH · Sep 11, 2011

FWIW The OP's truck has a powermax already.

Chris · Sep 11, 2011

Not trying to put words into his mouth, but id imagine he meant if youre going to run a 155/100, you might as well run a 175/100. for that matter, might as well run a 225/100. This is taking into account you have a tune that is built around that particular nozzle.

my personal preference based off the trucks we build is this. If you tow ALL the time heavy, leave stock sticks in it. If you tow on occassion but its heavy or you have bigger tires, stay with a 75 percent nozle. If you just tow a boat or something on occassion, do the 100 percent. Then base your turbo off the overall power you want to make, as it has just as much to do with towing egts as the injector.

strokin6L · Sep 11, 2011

yes i already know that...i saw it in his sig

strokin6L · Sep 11, 2011

Chris said:
Not trying to put words into his mouth, but id imagine he meant if youre going to run a 155/100, you might as well run a 175/100. for that matter, might as well run a 225/100. This is taking into account you have a tune that is built around that particular nozzle.

my personal preference based off the trucks we build is this. If you tow ALL the time heavy, leave stock sticks in it. If you tow on occassion but its heavy or you have bigger tires, stay with a 75 percent nozle. If you just tow a boat or something on occassion, do the 100 percent. Then base your turbo off the overall power you want to make, as it has just as much to do with towing egts as the injector.

yeah that's why when i was ready to do turbo and injectors, eric at ID told me to do the injectors first then do turbo after. Said it was easier to tune it that way.

Chris · Sep 11, 2011

strokin6L said:
the guys trucks that have those injector sizes....all have 100% nozzles

then it sounds to me they have a tune that is requesting a lot of pw in a towing situation, or the icp at that particular point is commanded to be higher. say both injectors are only being commanded to 1ms of open time w/ the same icp, niether the 155 or 175 will be emptied and both will have flowed the same amount of fuel.

Now to really throw a kink into the mix, are they the same 100 percent nozzles, as in, same style, make, hole count etc etc.

Chris · Sep 11, 2011

i agree on doing the injectors first too. Like said above if youre not going over 500 horse, i dont see any benefit in running a powermax or any turbo other than stock. (unless youre going to build the worlds most efficient, fastest spooling set of twins ever)

Gearhead · Sep 11, 2011

155/50% maybe?

strokin6L · Sep 11, 2011

i understand any injector can be turned down to keep egt's lower and keep the smoke down when towing, but how big of an injector can a person really go with and still be able to be turned down to keep egt's in spec and the smoke minimal? For towing the 25K lbs like the OP will be doing alot, the 155 injector with smaller than 100% would probably be better than one with the 100% nozzle like you suggested matt. I know my 190's with 75% nozzles still haze just slightly with my tow tune. Even if i punch the throttle in park with my tow tune...it'll throw out a nice cloud of smoke. But on my race tune, the 64mm still wont clean them up at WOT... there's still a bunch fuel left over.

SIX_OHH · Sep 11, 2011

I thought I remembered a respected tuner...eric or matt maybe saying its not as easy to pull fuel as we think it is?

strokin6L · Sep 11, 2011

Smut said:
I thought I remembered a respected tuner...eric or matt maybe saying its not as easy to pull fuel as we think it is?

No....eric has told me many times that he can pull fuel or max it out, but how much can be pulled from a large injector...is what i'm asking. I know even a large injector such as a 275cc can be turned down, but how far can fuel be backed off? Can a 275cc injector be backed off as much to flow like a 155? That's what i'm wondering. I know nozzle size plays a role to, but i know eric has told me that any injector can be turned down reguardless the nozzle size, but how far can they be turned down?

SIX_OHH · Sep 11, 2011

Thats what Im wondering. assumeing avg 100% nozzle, if there is such a thing

Stroker04 · Sep 12, 2011

I have the powermax with stock injectors right now, however I still have my stock 04 turbo. I don't tow 25k very often...I tow only occassionally. I do have slightly bigger tires on my truck about 35s most of the time my truck is unloaded though. So I could go with the 175/75?

SIX_OHH · Sep 12, 2011

175/100

Stroker04 · Sep 12, 2011

Maybe I could go with 190s and a 75% nozzle then have it tuned down on the tow file.

Gearhead · Sep 12, 2011

Can anyone tell me the difference in flow of a 155cc and 255cc injector with a 50% nozzle at 1500psi and 1ms of pulsewidth? And I don't mean the number.....