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Anyone regret doing a Cummins swap?
- Thread starter YotaAtieToo
- Start date
35s (315/75R16) and 3.54s were a decent combo on my old '97 Dodge with the NV4500. Stock was 245/75R16s, and it was way too low when running on the interstate. I went to 255/85R16s shortly after I got it, then ran 315s on it for the rest of the 16 years I drove it. Was a decent compromise for DD use and towing (~8k of Blazer and trailer, or 10k 5th wheel). I always thought a 6 speed would be a big improvement, but governor springs at least let you wind it up enough to up shift without loosing too much momentum or boost. It's been 10 years, but I seem to recall that it when pulling hills you wanted to be 1900+ RPM, and keep the boots in the low 30s to manage EGTs.
POR
Well-known member
- Joined
- May 21, 2020
- Messages
- 361
Idk about all that race car lifted truck math hahaha.. what is know is a 24v auto with 4.10 and 295 tires (iirc) is 1900 rpm is 60 mph and that will net you about 17mpg unloaded cruising down the freeway. I dont do all the micro manage gauges. That ****s waaay to stressful lol. I forget what mph 2100 gives you. Ill check today. But I do remember at 2100 rpm you loose like 3 mpg. 2100 rpm gives me 64mph ish
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Snowy
Well-known member
Anyone have any input on ideal gearing/tire size/rpm for the 12v? I’m stuck in my room at work trying to adjust to night shift and figured id nerd out on it
There is conflicting info on what OD an nv4500 in a dodge has, but for practical comparison I’d say it’s close enough that guys with 2nd gen dodges are going to be really close. My ZF5 is 0.77. Also, my tach isn’t hooked up yet, and I can’t really remember what rpm was at what speed before
so just going off feel, 55 feels like where it really wants to easily cruise 60 isn’t bad, 65 is ok and 70 or more feels like its pushing it.
Currently 3.55s and 285s but they measure 15’’ hub to ground, speedo is dead on with gps.
Left is current, right is with 33.5” rolling radius tires (best guess on 35s)
8mph gain at the same rpm doesn’t seem right? I felt like my buddies who put 35s on their diesels all said it was about 5mph
Another option for conversation sake would be gear swap, id like to upgrade the brakes and the 05+ axle swap seems to make more and more sense than anything. 3.31s, and 3.73s are common enough.
3.31 left and 3.73 right with 35s
Wouldn’t be opposed to 37s either if it did make it tow like ass. Part of me feels like the Cummins likes tall gears and having a tall OD with direct gear having decent rpm might be nice and possibly more useable?
37s (36 rolling radius?) 3.55 left, 3.73 right
37s and 3.55s would be exactly the same as 3.31s and 35s apparently. 37s on tow rig is semi dumb, but the trips I have planned, it would be nice to do some mild trails in this and the long ass truck needs all the help it can get.
I’m sure it would be great having mega tall gears empty, just now sure how low is too low rpm wise for open highway towing? I don’t mind down shifting and slowing down for hills. But will it be happy at 1800 rpm and 75 with a decent trailer behind?
Wading through a lot of really bad, or not applicable advice that's been thrown out since this post.
In order, I'd work down this list to see where you want to go.
Get a tach working, you're playing a silly guessing game right now without knowing the actual RPM at a given speed.
Decide on your use case. Towing a majority of the time or knocking down highway miles empty?
Assuming that you care more about towing. Target a 1850 - 2000rpm, cruising RPM in top gear at whatever speed you're going to be towing the trailer. RPM is not a huge driver of fuel mileage when towing, it takes a given amount of fuel to move a brick through the air at highway speeds. Light throttle, empty is different from a mileage perspective, but will still be fine in that RPM range. It also will be safer for you to add fuel down the road as well.
Do whatever you please to get to the right final drive ratio, knowing that larger tires are always going to be an efficiency hit in both mileage and power compared to deeper axle gears with a smaller tire.
-Disclaimer, I'm only speaking from experience on the MDT side of things specific to 5.9/6.7's. I've not had one in a pickup truck.
Burns
Well-known member
Last fall before I put the truck in storage, I bought some Power Driven PowerJet injectors to replace my x.014’s. Easy swap out but they suggested using the thin sealing washers. Ever since I’ve had two injectors that have never fully sealed, even when over torquing the nuts a smidge. Swapped sealing washers a couple times. Checked the torque of the body of the injector. Nada. Basically I think my head is slightly rough in the injector hole. Anyways talked with Power Driven right before winter and they said I could swap to the medium washers.
Yanked the truck outa storage last weekend. Already had medium washers. So this weekend that was the plan. Took 30mins and I had all the injectors out. Cleaning everything up I noticed something……one of my injectors is SCORCHED. Note, it wasn’t even one of the leaky copper sealing washer holes.
So here I sit, planned to use the truck today but now she’s out of commission until I get ahold of Power Driven.
Things to note:
1) the scorched injector doesn’t have a flow straightener/pre filter (idk what it actually is)
2) Note where the pick is, it looks like the nozzle is recessed further down thank the other injectors
3) For reference….she is BEAT UPPPPP
4) when pulled for reference (yes that’s RTV on hole #1, I was desperate after yanking all the **** part numerous times)
Yanked the truck outa storage last weekend. Already had medium washers. So this weekend that was the plan. Took 30mins and I had all the injectors out. Cleaning everything up I noticed something……one of my injectors is SCORCHED. Note, it wasn’t even one of the leaky copper sealing washer holes.
So here I sit, planned to use the truck today but now she’s out of commission until I get ahold of Power Driven.
Things to note:
1) the scorched injector doesn’t have a flow straightener/pre filter (idk what it actually is)
2) Note where the pick is, it looks like the nozzle is recessed further down thank the other injectors
3) For reference….she is BEAT UPPPPP
4) when pulled for reference (yes that’s RTV on hole #1, I was desperate after yanking all the **** part numerous times)
V30crewcab
Well-known member
just needs a wire wheel and then use the thicker washer. I had one injector on a 4bt in my dads truck doing the same thing. all I could figure is the head was machined slightly deeper on that hole.
Burns
Well-known member
Opinion on the fact that is doesnt have the strainer doodad and the tip being recessed down a smidge? ........cause Ill huck them all back in. I just dont want to be pulling them all again next week
Edit: The tip and sealing part look fine. I just worry as the body of it looks like its been through HELL
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V30crewcab
Well-known member
that is kinda wierd its missing that. had to have been shipped out that way. the body looking rough won't hurt anything.
Burns
Well-known member
cleaned them all up. Put a dab of dielectric on the washer, slid the washers on, injectors in, torque to 50 (torque is designated at 44). Reconnect everything. Bingo Bango.
I DID SWITCH cylinder 2 and 1 injectors. Original cylinder one injector is the one that ALWAYS leaked. Figured I’d switch holes to see if it still leaks, just in a different hole…telling me the injector is the issue. Old injector 2 is the scorched one, it’s now on hole 1 just in case Power Driven will warranty it, that way I can yank it super easy and quick.
idled in the driveway, no leaks yet. To be fair….it usually leaked after a rip on the highway/around town. So that’ll be later tonight.
Post idling, cylinder one:
Cylinder 2:
Cylinder 3:
Cylinder 4:
Cylinder 5:
Cylinder 6:
Will update post highway rip
I DID SWITCH cylinder 2 and 1 injectors. Original cylinder one injector is the one that ALWAYS leaked. Figured I’d switch holes to see if it still leaks, just in a different hole…telling me the injector is the issue. Old injector 2 is the scorched one, it’s now on hole 1 just in case Power Driven will warranty it, that way I can yank it super easy and quick.
idled in the driveway, no leaks yet. To be fair….it usually leaked after a rip on the highway/around town. So that’ll be later tonight.
Post idling, cylinder one:
Cylinder 2:
Cylinder 3:
Cylinder 4:
Cylinder 5:
Cylinder 6:
Will update post highway rip
![[486]](https://data.irate4x4.com/avatars/m/0/94.jpg?1700178133){kind=avatar}
[486]
smell-o-vision
edge filters are common to remove when you're going to 'actual size' nozzles
clean your bores out better, if the injector's bottoming on something that isn't the copper washer
I'll also anneal my copper washers when I'm reusing them, just heat them up to glowing and they'll be soft again (and all the carbon will fall off easily)
clean your bores out better, if the injector's bottoming on something that isn't the copper washer
I'll also anneal my copper washers when I'm reusing them, just heat them up to glowing and they'll be soft again (and all the carbon will fall off easily)
Burns
Well-known member
Update: Two of the dirty ****s are still leaking. Leaks followed the injectors when I switched them.
Called Power Driven and they actually said that I could warranty them. They gave me the choice of them sending me two of them to replace my problem injectors ORRRRRR a whole set because it turns out they changed the design and are using new injector bodies. So of course I chose the latter. No clue on timeline, but will post comparative pics when received.
Called Power Driven and they actually said that I could warranty them. They gave me the choice of them sending me two of them to replace my problem injectors ORRRRRR a whole set because it turns out they changed the design and are using new injector bodies. So of course I chose the latter. No clue on timeline, but will post comparative pics when received.
Alexis700
tomboy
They are a stand up company, sucks they leaked but **** happens.
Havent ran any of PDDs injectors but havent heard anything bad about them.
I buy iniectors from DAP, have had good luck with their stuff. Have a set of 7x.011 VCOs coming for the old 24 valve, $450 is hard to beat. Have 7x.012 SAC in it now, they run good but too smokey for street driving. Big nozzle hole and SAC is going to be dirty.
Main reason I order from DAP is they have P pump pop pressure 24 valve iniectors on the shelf, decent customer service, and good pricing. Also got a billet S475 from them for $1000 shipped.
Levigarrett76
Glass Half Empty
Had good luck with dap p-pump 24v injectors tooThey are a stand up company, sucks they leaked but **** happens.
Havent ran any of PDDs injectors but havent heard anything bad about them.
I buy iniectors from DAP, have had good luck with their stuff. Have a set of 7x.011 VCOs coming for the old 24 valve, $450 is hard to beat. Have 7x.012 SAC in it now, they run good but too smokey for street driving. Big nozzle hole and SAC is going to be dirty.
Main reason I order from DAP is they have P pump pop pressure 24 valve iniectors on the shelf, decent customer service, and good pricing. Also got a billet S475 from them for $1000 shipped.
I think they were 7x something, really mild
YotaAtieToo
Thick skull
- Thread starter
- #1,154
Dumb question:
I have not researched injectors at all.
Is there any advantages to aftermarket injectors when not trying to make a ton of power? I'd like to be 350-400 useable hp. Like tow up a grade and not have to watch the Pyro like a hawk.
Pretty sure the stock ones will do what I want, just curious if some smaller aftermarket ones would be better?
I have not researched injectors at all.
Is there any advantages to aftermarket injectors when not trying to make a ton of power? I'd like to be 350-400 useable hp. Like tow up a grade and not have to watch the Pyro like a hawk.
Pretty sure the stock ones will do what I want, just curious if some smaller aftermarket ones would be better?
Levigarrett76
Glass Half Empty
While it seems like you can make 350-400hp with stock injectors, I don't think that it would be usable or let you flat foot it on a grade with no worries.
Since I haven't actually built and tuned a Cummins yet and mostly just gathered knowledge listening to podcasts, I'm going to avoid talking out my ass much other than giving the basic opinion that it's a mechanical system, so your parts selection and how you set them up is what controls your "tune".
In order for a mechanical injection system to be tuned properly with over double the stock hp output (i.e. flat foot it on a grade without having to even be worried about the pyro), you're probably going to have to use a bunch of non-stock parts, and it won't end at just injectors.
Alexis700 seems to be well versed in swapping injectors and doing some tuning on a 12v. She could speak on firsthand experience.
That said, I like the results that the PDD guys are getting from powerjet injectors and the AFC live seems like a hell of a product.
V30crewcab
Well-known member
its a mechanical diesel, its not gonna be safe with it turned up. always gotta monitor the gauges. my truck does very well but still have to pay attention driving it.
YotaAtieToo
Thick skull
- Thread starter
- #1,158
Maybe 400hp is a high estimate.
325-350?
It's got a He351cw, aftermarket 6.0 i/c and a full 4" downpipe back. My thought was if the turbo and intercooler are from trucks with a factory 325hp, then 325-350hp should be pretty damn safe.
I don't know where I'm at now, I didn't touch the fuel yet. Just timing and go spring. But it will smoke quite a bit if you stomp it until it builds boost. Feels better than my 7.3 with a ts6 that was supposed to be ~300hp. I can flat foot it now with almost no worry of egts unless it's just being careless like pulling long grades in 5th.
I understand the concept of tuning a mechanical truck. I got fairy familiar with tuning my ve pump truck years ago. What I'm wondering is if there is any advantages to aftermarket injectors when not shooting for big power? Better mileage? Lower egts?
325-350?
It's got a He351cw, aftermarket 6.0 i/c and a full 4" downpipe back. My thought was if the turbo and intercooler are from trucks with a factory 325hp, then 325-350hp should be pretty damn safe.
I don't know where I'm at now, I didn't touch the fuel yet. Just timing and go spring. But it will smoke quite a bit if you stomp it until it builds boost. Feels better than my 7.3 with a ts6 that was supposed to be ~300hp. I can flat foot it now with almost no worry of egts unless it's just being careless like pulling long grades in 5th.
I understand the concept of tuning a mechanical truck. I got fairy familiar with tuning my ve pump truck years ago. What I'm wondering is if there is any advantages to aftermarket injectors when not shooting for big power? Better mileage? Lower egts?
GLTHFJ60
Stupid is as stupid does
As I understand it, if you move to an injector with more holes at the same total surface area, you would get more fuel atomization and potentially more efficiency through a cleaner burn.
[486]
smell-o-vision
215hp
YotaAtieToo
Thick skull
- Thread starter
- #1,161
That's 30 more than it came with215hp
That's kinda what I was wondering. Not to mention new vs ~200k mile units.
I've mostly written them off before, since every 12v I've seen with aftermarket injectors is smokey as ****. But that's probably mostly driver and tuner.
GLTHFJ60
Stupid is as stupid does
Compared to older injectors, yeah, there can be significant improvements with new (aftermarket or oem) injectors for sure. Pop pressure is how these are actuated obvs, and older injectors won't always meet spec, meaning they pop early at too low of a pressure. That alone can cause smoke because your injection timing is effectively being advanced, and it's not necessarily even between cylinders either. Injectors don't always wear at the same rate.
Aftermarket injectors does not automatically mean smokey, it's morons who put fire hose injectors on trucks with stock/small turbos. Match the nozzle orifice total surface area to your turbo setup and you won't get smokiness.
Also, properly adjust your AFC, that'll help a ton.
Burns
Well-known member
I could see you doing injectors for a smidge more power and to clean things up, which is why I most recently did them!
'96 12v with a Hamilton whatever "stage" head (it has poor swirl), sx364 turbo, built 215ppump (i think I set it around 320cc of fuel), 4'' intake piping and 4'' exhaust and in this first video its running standard 5x.014 power driven injectors. Smokes like a freight train but lights the turbo fast. ALWAYS HAZES. Towing....its a cloud up the entire highway 24/7........driving at 80 up the highway it chooches a constant small amount of black, just not a ****ing cloud like when towingdyno'ed at 490/1100'ish.
Video with 5x.014's:
In order to fix that because Im growing up I bought the power jet injectors. No changed to anything but the injectors and my haze nearly ent away and i easily got 2mpg better.....the turbo is lazy as **** now though and its way less "fun" to drive, but way more respectable. No dyno numbers.
video with power jets (550hp rated, stage 1's):
'96 12v with a Hamilton whatever "stage" head (it has poor swirl), sx364 turbo, built 215ppump (i think I set it around 320cc of fuel), 4'' intake piping and 4'' exhaust and in this first video its running standard 5x.014 power driven injectors. Smokes like a freight train but lights the turbo fast. ALWAYS HAZES. Towing....its a cloud up the entire highway 24/7........driving at 80 up the highway it chooches a constant small amount of black, just not a ****ing cloud like when towing
dyno'ed at 490/1100'ish.Video with 5x.014's:
In order to fix that because Im growing up I bought the power jet injectors. No changed to anything but the injectors and my haze nearly ent away and i easily got 2mpg better.....the turbo is lazy as **** now though and its way less "fun" to drive, but way more respectable. No dyno numbers.
video with power jets (550hp rated, stage 1's):
Levigarrett76
Glass Half Empty
7 hole (0.0085 inch holes) VCO
DAP Brand New 75HP Performance Injectors 7x0.0085 VCO
Check out the deal on DAP Brand New 75HP Performance Injectors 7x0.0085 VCO at Diesel Auto Power
www.dieselautopower.com
Cold starts were not bad, no haze idle etc. Clean a burn as the vp 44 with alot more fuel on tap and faster starts.
2wd drw auto regularly got 19-21 on hwy.
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Alexis700
tomboy
No way they were 7x.014, that is a huge nozzle. A 7x.012 is a "250" hp injector, which is what is currently in my 24 valve. Like Burns, the SAC 7x.012 leaves a constant haze at any load. Like just driving down the interstate, pull any hill and theres steady light black haze.
This is a cold start, 65 degrees.
I reccomend calling PDD for the 12 valve, tell them what you want it to do and they will probably reccomend one of their powerjet injectors.
Should be able to pick up some power, lower egt , and reduce smoke with a set of their powerjets. Your HE351 is an excellant towing turbo also, about the best option for 350 towing HP.
This is a cold start, 65 degrees.
I reccomend calling PDD for the 12 valve, tell them what you want it to do and they will probably reccomend one of their powerjet injectors.
Should be able to pick up some power, lower egt , and reduce smoke with a set of their powerjets. Your HE351 is an excellant towing turbo also, about the best option for 350 towing HP.
Levigarrett76
Glass Half Empty
I think you are right, for some reason i saved the file with 7x.014No way they were 7x.014, that is a huge nozzle. A 7x.012 is a "250" hp injector, which is what is currently in my 24 valve. Like Burns, the SAC 7x.012 leaves a constant haze at any load. Like just driving down the interstate, pull any hill and theres steady light black haze.
This is a cold start, 65 degrees.
I reccomend calling PDD for the 12 valve, tell them what you want it to do and they will probably reccomend one of their powerjet injectors.
Should be able to pick up some power, lower egt , and reduce smoke with a set of their powerjets. Your HE351 is an excellant towing turbo also, about the best option for 350 towing HP.
7 hole (0.0085 inch holes) VCO style i think they were?
DAP Brand New 75HP Performance Injectors 7x0.0085 VCO
Check out the deal on DAP Brand New 75HP Performance Injectors 7x0.0085 VCO at Diesel Auto Power
www.dieselautopower.com
Alexis700
tomboy
I was gonna say 7x.0085 should be it.I think you are right, for some reason i saved the file with 7x.014
7 hole (0.0085 inch holes) VCO style i think they were?
DAP Brand New 75HP Performance Injectors 7x0.0085 VCO
Check out the deal on DAP Brand New 75HP Performance Injectors 7x0.0085 VCO at Diesel Auto Powerwww.dieselautopower.com
I am hoping the 7x.011 vco is reasonably clean, dont really want to go smaller because it is getting a s475 under the s362. I just dont like the constant haze on highway and idle haze. Especially doing work in nice neighborhoods, dont want to be leaving a trail of grey smoke everywhere.
bad zuki
Bring Back Builds
- Joined
- Oct 2, 2023
- Messages
- 1,660
Pump stuff. - Bump the timing up, Delivery valves if its a 150-180 pump. Adjustable pump pressure screw, AFC Live for tuning. It absolutely changes towing in these things.
Injectors - I like stock 215 injectors or RV ones. Swap the tips and get them pop tested.
Upgraded fuel pump. Mechanical are up to 500hp+ IIRC.
Good dual disc organic clutch with valair master/slave.
Redneck head studs. Do one at a time.
My green truck was around 415 with those. I put 7x10s in the same truck and it didn’t get any more powerful, it just rolled way too much Coal and ran the pump dry. I also set it up for compound turbos, but never installed them.
Just the mods I listed will need to watch an egt gauge while towing. 7.3s don’t have egt problems like these do. If the afc live is on stock mode, it maxes out at 900*.
YotaAtieToo
Thick skull
- Thread starter
- #1,169
Funny, I just read not to do delivery valves for what I want. I believe it's a 185 hp pump. 95 auto 2wd donor.
Timing is bumped
Has arp studs already.
This is what I was wondering
So not at all what I want
A bunch of power is no good to me if I have to pedal it on grades.
Most likely a turbo thing. The hx35s are pretty restricted when bumping power. I know it's not the best out there, but my turbo and i/c should be a pretty big improvement over a stock 2nd gen.
SHARPMACHINE
Web Wheeler
Delivery valves were one of my first 12v mods. 3k since you do not wanna look at the egt gage, 4k makes max powa though.
Once tried doing it by just adding washers from a forum post, prefered the 3 or 4k...
Once tried doing it by just adding washers from a forum post, prefered the 3 or 4k...
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