Towing injector size

Reese99

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Jan 30, 2023
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Hey guys I've got a 03 6.6l lb7 with some injector issues. I've got 3 going out and am going to just do all of them while I'm in there. The pickup has a spade Tuner with an edge cts2 monitor for my guages, 4 inch straight pipe, and modified ppe valve. I'm looking to go bigger on injectors for towing. I haul a 15k lb camper all summer and am looking for comfortable power. I've been looking at some dynomite 50hp injectors but am open to any helpful information. The dynomite injectors will be $3500 not including gaskets.....I know u get what u pay for but does anyone know of another good brand or place to buy good injectors around moscow idaho area thats not gonna cost an arm and a leg? Not opposed to paying shipping either. Any thoughts on what size injectors? Eventually I plan to build the transmission and install a lift pump as well. If I can do injectors for a bit cheaper I'll be able to do those sooner. Thanks
 

Chevy1925

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i dont know what 50hp injectors equate to as genereally all the dmax stuff goes off percentage over stock. So a 30% over (30% more fuel than stock), 45% over, 60% over and so on. HP rating was an old cummins way of going about it.

for your towing, unless you have a means of tuning, stick with SAC00 injectors. you will run out of air long before your stock injectors are out of fuel when looking at a stand point of towing. a twin kit would be more beneficial here.
 

1FastBrick

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Dec 1, 2016
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i dont know what 50hp injectors equate to as genereally all the dmax stuff goes off percentage over stock. So a 30% over (30% more fuel than stock), 45% over, 60% over and so on. HP rating was an old cummins way of going about it.

for your towing, unless you have a means of tuning, stick with SAC00 injectors. you will run out of air long before your stock injectors are out of fuel when looking at a stand point of towing. a twin kit would be more beneficial here.
I don't know why DDP puts an HP value but that's their 25% over injector. https://dynomitediesel.com/collecti...r-50hp-dynomite-diesel?variant=39334252413002
 

1FastBrick

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Dec 1, 2016
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OP, I would recommend you speak to @Bdsankey on here. He is not only a vendor but he is a DDP Dealer as well and he can help you with your other parts needs.
 

Bdsankey

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Hey guys I've got a 03 6.6l lb7 with some injector issues. I've got 3 going out and am going to just do all of them while I'm in there. The pickup has a spade Tuner with an edge cts2 monitor for my guages, 4 inch straight pipe, and modified ppe valve. I'm looking to go bigger on injectors for towing. I haul a 15k lb camper all summer and am looking for comfortable power. I've been looking at some dynomite 50hp injectors but am open to any helpful information. The dynomite injectors will be $3500 not including gaskets.....I know u get what u pay for but does anyone know of another good brand or place to buy good injectors around moscow idaho area thats not gonna cost an arm and a leg? Not opposed to paying shipping either. Any thoughts on what size injectors? Eventually I plan to build the transmission and install a lift pump as well. If I can do injectors for a bit cheaper I'll be able to do those sooner. Thanks

Personally on an LB7 I find it very hard to pass up a SAC45% injector. They are great for stock HP levels up to around 650-700whp is where I like to stop with them before pulse really gets stretched out.

My shop carries Dynomite Diesel (DDP), Exergy, and S&S. Personally I stick to those 3 as I feel they are a high quality product with usually great turnaround times. I do have a set of cores here I keep in rotation to help customers out if needed. Josh is another vendor on this forum and he carries at least S&S as well.


We also do free shipping (all directions, including cores) on non-freight items for forum members. Let me know if I can help. I do know that I am less than $3500 for PN LB7-75 (reman 45%).
 

Reese99

New member
Jan 30, 2023
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Thanks everyone for your advice. Sorry for the late response but I have been reading all of these an looked into them. I've called about a dozen different shops and ended up buying a set of 20% over injectors throught Lincoln diesel. I'm not looking for a race pickup so from what I gathered 20% should give me what I was looking for in towing power. I am running a efi live tuner and was curious If it was worth trying to tune these injectors? I know theoretically they can run on stock but if I tuned it could I get better fuel economy and power? I bought a lift pump for it as well and I think over the summer I will look into a transmission build kit just to be safe. For the set up I'm running what kind of build kit would I need to keep the transmission on the safe side?
 

Bdsankey

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Thanks everyone for your advice. Sorry for the late response but I have been reading all of these an looked into them. I've called about a dozen different shops and ended up buying a set of 20% over injectors throught Lincoln diesel. I'm not looking for a race pickup so from what I gathered 20% should give me what I was looking for in towing power. I am running a efi live tuner and was curious If it was worth trying to tune these injectors? I know theoretically they can run on stock but if I tuned it could I get better fuel economy and power? I bought a lift pump for it as well and I think over the summer I will look into a transmission build kit just to be safe. For the set up I'm running what kind of build kit would I need to keep the transmission on the safe side?
You should really get retuned IMO.

As for a transmission, a high quality build kit will suit your needs if you're confident you can put it together. There also are many very competent builders across the country. Our kits (Goerend kits with additional parts) or the Limitless/Inglewood kits work extremely well.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Thanks everyone for your advice. Sorry for the late response but I have been reading all of these an looked into them. I've called about a dozen different shops and ended up buying a set of 20% over injectors throught Lincoln diesel. I'm not looking for a race pickup so from what I gathered 20% should give me what I was looking for in towing power. I am running a efi live tuner and was curious If it was worth trying to tune these injectors? I know theoretically they can run on stock but if I tuned it could I get better fuel economy and power? I bought a lift pump for it as well and I think over the summer I will look into a transmission build kit just to be safe. For the set up I'm running what kind of build kit would I need to keep the transmission on the safe side?
im not sure why you even posted here asking us for help on this. 😑

had you waited, we could have told you that YES you will need a retune, you will be seeing high egt's and poor mpg without it. Their ad completely contradicts its self and LDS was also the ones that claimed you didnt need a retune for SAC 45% over (wasnt true). We could have told you LDS (where you got your injectors) have fallen off on quality and its very likley you could be right back into that engine again replacing a few injectors. We could have told you, it doesnt matter if its race truck or not, a set of SAC injectors would completely solve the inherited LB7 failure issue and since im betting you got the reman 20% overs, they are just the old style VOC injector that WILL fail again.

So anyhow, good luck on your adventure.
 

Bdsankey

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im not sure why you even posted here asking us for help on this. 😑

had you waited, we could have told you that YES you will need a retune, you will be seeing high egt's and poor mpg without it. Their ad completely contradicts its self and LDS was also the ones that claimed you didnt need a retune for SAC 45% over (wasnt true). We could have told you LDS (where you got your injectors) have fallen off on quality and its very likley you could be right back into that engine again replacing a few injectors. We could have told you, it doesnt matter if its race truck or not, a set of SAC injectors would completely solve the inherited LB7 failure issue and since im betting you got the reman 20% overs, they are just the old style VOC injector that WILL fail again.

So anyhow, good luck on your adventure.
I didn't want to make the same post but...........yeah.......... LDS = no from our shop. I've had too many issues with them over the years where Lauren is instantly blaming the tuning or anything else on the truck. In the last 2 months I've had 3 guys ask for injector pricing, go to LDS due to cost, then come back saying they have hazing etc within a few thousand miles.


Life lesson, LDS is not the company they used to be ever since they got dropped by S&S for undercutting every dealer on the planet.
 
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Reese99

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Jan 30, 2023
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I was not aware they dropped off. I've read up on a couple different forums for injectors and it seemed lds was a pretty good injector for its buck from everything I read on it? I got the new 20% injectors. I would have gone the sac 45% injectors but then I would need to modify just about everything else to make up for it wouldn't I? I'd assume I'd need lift pump, built trans, and more air at least? I paid 2800 not including core and got the injectors and lift pump. If I'm better off returning them and going another route I will but if the injectors themselves are the same price I won't be able to do lift pump or built trans. I don't want stock injector size back in so if I go with the sac injectors what size would I need to do? Can I get away with just tuning the sac45? Will anything over 20% cause me to fight egt?
 

2004LB7

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With SAC45s you can get away with just tuning. The tuner can make the appropriate changes so the HP gain is nothing or minimal. If you want to turn it up later a simple tuning change will do it
 

Bdsankey

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I was not aware they dropped off. I've read up on a couple different forums for injectors and it seemed lds was a pretty good injector for its buck from everything I read on it? I got the new 20% injectors. I would have gone the sac 45% injectors but then I would need to modify just about everything else to make up for it wouldn't I? I'd assume I'd need lift pump, built trans, and more air at least? I paid 2800 not including core and got the injectors and lift pump. If I'm better off returning them and going another route I will but if the injectors themselves are the same price I won't be able to do lift pump or built trans. I don't want stock injector size back in so if I go with the sac injectors what size would I need to do? Can I get away with just tuning the sac45? Will anything over 20% cause me to fight egt?
You need nothing beyond tuning to make SAC45% run on a stock truck. They can make below stock HP or up to 650-700hp before they start getting stretched out on pulse IMO.

Long story short, you don't need ANY mods (beyond tuning IMO) to properly run SAC45% on an otherwise stock truck. There's this old saying, "you get what you pay for". This saying is extremely true with these trucks.
 

DAVe3283

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I actually have had the opposite experience with SAC45s. I bought one of the first set of SAC injectors S&S made for my blue truck, and they have been flawless.

My brother recently put LDS SAC45 injectors in his truck, and they took a little bit of tune wrangling but I got them to run pretty well with minimal effort. Balance rates are fantastic and steady.

Given my prior good experience with S&S, I paid the (substantial) premium to get S&S instead of LDS SAC45 injectors in my Suburban, and they have been an absolute pain in my ass. Balance rates are garbage, diesel smell at idle that I can't quite kick with pressure and timing, and they are being really picky to tune. I almost have them dialed in, but honestly, I regret buying the S&S over the LDS at this point.
 
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Reese99

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Jan 30, 2023
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Sounds like the sac45 is the most common suggestion. I'm not opposed to returning the 20% for a sac45 if they can be tuned right. It would be nice to be able to have that option for down the road to allow for more power. If I did those I would be going for reman sac45s tho. Is that a waste of money? By tuning these down so much will that effect mpg? I shouldn't have to worry about egt with these tuned properly right?
 
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DAVe3283

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Tuned right, SAC45s will run great. It's too early to say for sure on mileage for my Suburban, but my truck with SAC75s gets the same mileage it used to.

You won't have EGT problems at or near stock power either. If you're turning it up, a gauge is wise, regardless of what injectors you run.

Sent from my FlashScan V2 using Tapatalk
 
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Delta.Speed

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Mar 26, 2022
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OP, I would recommend you speak to @Bdsankey on here. He is not only a vendor but he is a DDP Dealer as well and he can help you with your other parts needs.
+1 on getting with @Bdsankey for all your Duramax needs. When I first got my truck I made a lot of mistakes that cost me time and money because I called vendors directly and they would sell me stuff without it being needed and because I was new to diesels I didn't know any better.

When I first got with Brad I showed him my parts list that I had put together with the other vendors and the first thing he did was take off over $1,200 in stuff I had been recommended that wasn't necessary. He has had my complete trust since. Can't tell you how many times I've reached out asking about a certain upgrade he could've sold me and made money on and has instead convinced me it's unnecessary.

I purchased 30% over SAC injectors from Lincoln Diesel and I've been driving the truck for only two days after getting them and so far they seem fine. I do have a ticking noise I have yet to figure out and I'm not sure if it's one of the injectors.

Also as Brad said above, even with a stock truck you can go to 45% SAC, which I would've done if I hadn't found that out from Brad after being sold the 30% already.

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