Need Injector Help - Please chime in

[07whiteranch]

Alright guys, need your help as i cant get a solid answer from the home work i have done.

I am wanting to do 155's or 175 injectors. Please see my other mods below and suggest what the best possbile set up would be for a daily driver along with any other fuel systems, rr's, crossover lines, larger pumps, etc. I want to do it right, so i have not set a budget to complete this project. I do plan to keep the stock turbo for some time.

[Countryboy07]

Originally Posted by 07whiteranch

I am wanting to do 155's or 175 injectors. Please see my other mods below and suggest what the best possbile set up would be for a daily driver (Since you are wanting to keep this a daily driver and still use the stock turbo, I would sugguest nothing over 155cc injectors. I have seen a few run with 155's and they run good!) along with any other fuel systems (Check out Trusted Performance. They have top notch quality and I have personally seen their stage 1-3 systems and help install them. Very good guys to work with.) ,rr's, crossover lines, larger pumps, etc. I want to do it right, so i have not set a budget to complete this project (Personally, I would set aside around $2,000, or a little more as I haven't really looked at the price of the 155's, to be able to get your injectors and your fuel system all set up the right way the first time) I do plan to keep the stock turbo for some time.

My answers are in RED. If you need anything else, feel free to ask

-French

[jensenrcng]

do you need head studs to put in 155s?

[SamW]

Originally Posted by jensenrcng

do you need head studs to put in 155s?

yes, youll want studs a full egr delete for any upgraded injectors. I have 190s and they work well with a stock turbo, it does run pretty hot and I would suggest no bigger then 175s for a DD. there is alot of fuel out of those 190s, 155s will be enough fuel for most. you will want a an RR and Pump that will hold 55 psi. my fass feeds the 190s I have pretty well. you will also want upgraded fuel lines and a crossover line of you decide to not go with an RR setup.your going to be in alot more than just sticking injectors in... I wouldnt put them into a motor without studs and a egr delete and fuel lines, FASS or other upgraded pump... my fuel system was around 1000, the injectors were 1700, egr delete and studs were another 1000 plus labor so your going to be looking at more than 2000 for everything to support those injectors. If you are going to stay stock on the turbo then dont go with more than 155s. 155s will go well with a 62mm turbo or a modded vgt. if you want a little more power at some point.

[hpprose]

Does anyone know the difference between 155 and 175's with fuel pulled out on a dyno?

I would assume that most tuners are pulling fuel out on anything above 155 with a stock turbo. If that is true (not saying it is) then you will probably end up with the same horsepower and less smoke with the 155's. Larger injectors put more fuel into the combustion chamber, increasing EGT’s. Larger turbos will add more air to keep the EGT’s manageable. On a stock turbo which is pretty much maxed out with stock injectors, there isn’t really more air available. So, tuner will pull fuel out to manage EGT’s.

If you were looking to do a turbo sooner than later, then 175's would be a good option, but it not, 155's will be a good size for a stock turbo with very little to be concerned with.

Fuel Systems, as Countryboy07 mentioned, the Trusted Performance stuff is very nice. If you are looking at doing 155cc injectors, the stock pump may be able to keep up. So, I would recommend upgrading the lines to the front of the cylinder heads (their Stage I) and a fuel pressure gauge. As long as your fuel pressure isn’t dropping, you are fine. If it does start to drop, then I would look at a FASS or Airdog pump and add a crossover line to the Stage I. (If you opt for 175’s you will more than likely need the fuel pump. Still watch your gauge, but plan on a pump.)

If you opt for 175’s, you may want to consider a water injection system. These systems add extra oxygen and cool the charge air temp, to help manage egt’s.


Hey Jensenrcng,

Head Studs, that is pretty much a loaded question. A stock truck can and will blows the head gaskets. So, if you plan on increasing the horsepower, heat inside the combustion chamber, etc, start saving for them. Can you get away without, depends on what day your truck was built.

[jensenrcng]

thanks guys, will i need a new custom tune for the injectors?

[RescueF250]

Yes you would need a custom tune.

[mdub707]

Originally Posted by hpprose

Does anyone know the difference between 155 and 175's with fuel pulled out on a dyno?

I would assume that most tuners are pulling fuel out on anything above 155 with a stock turbo. If that is true (not saying it is) then you will probably end up with the same horsepower and less smoke with the 155's. Larger injectors put more fuel into the combustion chamber, increasing EGT’s. Larger turbos will add more air to keep the EGT’s manageable. On a stock turbo which is pretty much maxed out with stock injectors, there isn’t really more air available. So, tuner will pull fuel out to manage EGT’s.

If you were looking to do a turbo sooner than later, then 175's would be a good option, but it not, 155's will be a good size for a stock turbo with very little to be concerned with.

Fuel Systems, as Countryboy07 mentioned, the Trusted Performance stuff is very nice. If you are looking at doing 155cc injectors, the stock pump may be able to keep up. So, I would recommend upgrading the lines to the front of the cylinder heads (their Stage I) and a fuel pressure gauge. As long as your fuel pressure isn’t dropping, you are fine. If it does start to drop, then I would look at a FASS or Airdog pump and add a crossover line to the Stage I. (If you opt for 175’s you will more than likely need the fuel pump. Still watch your gauge, but plan on a pump.)

If you opt for 175’s, you may want to consider a water injection system. These systems add extra oxygen and cool the charge air temp, to help manage egt’s.


Hey Jensenrcng,

Head Studs, that is pretty much a loaded question. A stock truck can and will blows the head gaskets. So, if you plan on increasing the horsepower, heat inside the combustion chamber, etc, start saving for them. Can you get away without, depends on what day your truck was built.

What about running a larger than necessary injector, but keeping the fuel pulses low. It allows a lot more fuel to be put into the combustion chamber with less timing, keeping cylinder pressures lower right? I would think this would boil down to who is doing your tuning...

[hpprose]

Originally Posted by mdub707

What about running a larger than necessary injector, but keeping the fuel pulses low. It allows a lot more fuel to be put into the combustion chamber with less timing, keeping cylinder pressures lower right? I would think this would boil down to who is doing your tuning...

Yes and no. I don't want to get into injector design and modification, but our injectors really don't do that very well. You will end up with lots of smoke and maybe a little more power. But mostly lots of smoke.

The guys out there tuning these trucks and really know what they are doing are able to make good power out of smaller injectors. If you use larger injectors with larger nozzles, but have the fuel pulled back, you may end up netting a little more power but not much. It will certainly have more smoke, which isn't good.

But that is why I asked if anyone knew the difference between 155’s at full tilt vs 175’s pulled back on a dyno. I’m betting that the difference is less than 20 hp. But in regards to your question, 200’s or larger vs 155’s, 200’s will yield you more power because you cannot pull enough fuel out and they will be very smoky because of the nozzle size. Also, EGT’s will be very high.

[mdub707]

Originally Posted by hpprose

Yes and no. I don't want to get into injector design and modification, but our injectors really don't do that very well. You will end up with lots of smoke and maybe a little more power. But mostly lots of smoke.

The guys out there tuning these trucks and really know what they are doing are able to make good power out of smaller injectors. If you use larger injectors with larger nozzles, but have the fuel pulled back, you may end up netting a little more power but not much. It will certainly have more smoke, which isn't good.

But that is why I asked if anyone knew the difference between 155’s at full tilt vs 175’s pulled back on a dyno. I’m betting that the difference is less than 20 hp. But in regards to your question, 200’s or larger vs 155’s, 200’s will yield you more power because you cannot pull enough fuel out and they will be very smoky because of the nozzle size. Also, EGT’s will be very high.

Agreed, that seems to be the consensus I gathered too, I was just asking about it though after doing some reading on some other sites where a few of the duramax guys were running ridiculously huge injectors so that they could inject a large amount of fuel with low timing to keep cylinder pressures down and it just got me thinking...

Thanks for the reply.