Engine/Transmission (1994 - 1998) EGTs too low?

[Cosmo]

Ok so I bought this 12-valve a little bit ago in preparation for a 4200 mile haul across the country towing a ~10k pound trailer.



Already on the truck when I bought it: AFE intake/filter, MBRP 4" exhaust.

First thing in: EGT/Boost/Trans temp gauges.

Engine tweaks: Light AFC spring, 4k Gov springs, 60 lb valve springs, "#5" fuel plate (which doesn't look anything like a #5, it looks like a #100), FS2500 bypass oil filter, Airdog 150

I also put a beefy Curt hitch and a set of Firestone air bags under the rear end, and rebuilt the trans with upgraded clutches, aluminum kickdown accumulator piston, a transgo shift kit, and a double-disc torque converter rated to about 850 lb-ft.


The EGT probe is in the turbo outlet elbow, as the split exhaust manifold was ******* me off with its divider.

At any rate, I've noticed that WOT from 0-~50 mph I'm seeing EGTs of about 680 degrees, and very little smoke. I'm A-OK with not blowing a lot of smoke, however sub-700 degree temps seem really low compared to what I was used to seeing with my 08 Cummins. On that thing, which was grossly overfueled in Hot mode, EGTs were normally in the 1000-1300 range, and on a couple of runs up the onramp it hit 1450.


Don't get me wrong, the lower the EGTs the better, imho, but I just want to make sure I'm getting as much fuel as it can use. The trailer is going to be pretty well loaded, and we've got quite a few hills between east coast and west coast.

This being my first experience with a 12 valve, what should I expect for EGTs? Everyone was telling me that the #5 fuel plate was a bad idea because it would smoke a lot and temps would be through the roof, but I'm not seeing that - of course after comparing the fuel plate I got (ebay cheapo) to the picture of the popular fuel plates, it's definitely a #100.


What kind of power can I expect to make with that setup? I fully intend on going to the aftermarket with the turbo sometime down the road, but for now I just need it set up well enough to get me across the country.

Edit: I guess I should note that I installed the fuel plate and the AFC I believe in the stock locations. I did not grind the foot off or do anything else to them.

 

[NIsaacs]

The EGT probe is in the turbo outlet elbow, as the split exhaust manifold was ******* me off with its divider.



Thats funny:-laf





You should see 900/1000 degrees when pulling hard for extended periods. All my trucks have post turbo pyro's, however I am in the minority here. Don't go over 1000 degrees and you will be fine.



The TDR egt's police will arrest us both for this tho



Nick

 

[Cosmo]

I thought about taking a grinder to the divider and opening it up, and I read somewhere that someone recommended doing so (at least on the turbo) because the wastegate was only dumping the back three cyls, but in the end I didn't want to deal with it. If I had pulled the head, I would have, but instead I just did the valve springs in the truck and left the head alone.

I know the EGT police would like us to have 6 probes in each of the exhaust manifold ports, but I don't care that much.

Does the exhaust gas temp drop that much as it goes through the turbo? I know the turbo has a constant supply of oil going through it to cool it off, but I can't imagine there would be more than a hundred or two degrees in temp difference pre versus post turbo.

Without a load, what are your typical EGTs like WOT?

 

[BigPapa]

Does the exhaust gas temp drop that much as it goes through the turbo?

Yes.



Your post-turbo EGT's sound about right to me for your fuel mods.

 

[Bob4x4]

I have run t/couple pre and post. I have seen 600 degree diff when hitting a grade. it takes a good amount of time before the temps get to the advertised

300 diff

To each his own

 

[JLEONARD]

Marine engines are also post turbo. When I had my 6BTA 270 I would see 900 F at wide open throttle, 30 psi boost. That was just at the high end of Cummins specs for that engine.

 

[DRAG DIESEL]

1450* post turbo?:-laf

were trying to keep the motor alive, turbo don't care how hot the exhaust is when its spinning.

1000* is safe(r). i'd say your at max fuel for your air supply.

 

[BigPapa]

I THOUGHT I read that his '08 was pre-turbo. Now I can't find it. Maybe I just assumed.

 

[Cosmo]

The 6. 7 EGT probe was in one of the EGR blockoff plates about 2" from an exhaust port. HPCR trucks are perfectly happy running up to about 1500 degrees, but higher than that there's definite risk of doom.

 

[JKosten]

The main difference you are seeing between years is that 07 and newer run higher egt's because of the piston design to burn off emissions.

In a 12v it will not get nearly as hot daily driving with factory injectors.

I am around 500 pre-turbo in town and 600 cruising at 70. Pulling hills or stepping on pedal it has climbed up to 900ish. The big help in egt reduction is allowing the motor to breath. I have a 3" intake horn and 4" turbo back Silverline Stainless system (although it keeps getting shorter and shorter... it is dumping before the axle as of right now)

 

[Nyoest]

Is it a digital or analog pyro? I've noticed a big difference in climb rate between the two, the digitals being much faster.

Have you tried to adjust your afc for faster fueling after the kit? Iirc I played with mine for an hour and it made a nice difference.

 

[Bob4x4]

The main difference you are seeing between years is that 07 and newer run higher egt's because of the piston design to burn off emissions.



In a 12v it will not get nearly as hot daily driving with factory injectors.



I am around 500 pre-turbo in town and 600 cruising at 70. Pulling hills or stepping on pedal it has climbed up to 900ish. The big help in egt reduction is allowing the motor to breath. I have a 3" intake horn and 4" turbo back Silverline Stainless system (although it keeps getting shorter and shorter... it is dumping before the axle as of right now)

:-laf:-laf:-laf:-laf Who runs stock injectors in a 12 valve

 

[JKosten]

:-laf:-laf:-laf:-laf Who runs stock injectors in a 12 valve

I only have 25k on them since they were replaced a month before I bought it. I am looking for a good reason to upgrade...



Anyone have thoughts on these: DODGE/CUMMINS 5. 9L 88-02 :: PERFORMANCE INJECTORS :: 1994-98 DODGE STAGE 2 PERFORMANCE INJECTOR - Pensacola Fuel Injection | Worlds #1 Diesel Rebuilder

 

[Bob4x4]

Anyone have thoughts on these: DODGE/CUMMINS 5. 9L 88-02 :: PERFORMANCE INJECTORS :: 1994-98 DODGE STAGE 2 PERFORMANCE INJECTOR - Pensacola Fuel Injection | Worlds #1 Diesel Rebuilder

My guess they are a copy-not bosch 370 type injector. call and ask maybe they will tell you what brand/country they are from

 

[DRAG DIESEL]

:-laf:-laf:-laf:-laf Who runs stock injectors in a 12 valve

Me :{:{:{:{

 

[Cosmo]

Is it a digital or analog pyro? I've noticed a big difference in climb rate between the two, the digitals being much faster.

Have you tried to adjust your afc for faster fueling after the kit? Iirc I played with mine for an hour and it made a nice difference.

Digital pyro.

I haven't touched it since I bolted it back together... I was more concerned with getting the truck on the road and getting out of town. I probably should tweak it, but I just haven't had the time and I really don't want to adjust it and then load it up and find out I've got a problem...

:-laf:-laf:-laf:-laf Who runs stock injectors in a 12 valve

I'm currently running stock injectors. I was under the impression that I needed more air before bothering with delivery valves or injectors.

Oh, and even with the 4k governor springs I noticed that it won't pull over about 2800 rpm before it shifts, which is also just fine with me because I figure the stock cam isn't really made for making power in the 3-4000 range.


Overall, the truck seems to be running fine, it's just a major departure from the 08 with the electronic fuel system and VGT turbo. That VGT is slick as hell, and if I had a 24-valve I'd be putting one in.