1,350*F (pre-turbo) @ 22psi

[rich m]

... I have this friend... .



He's got a 1st-Gen (I think it's a 93, but I won't guarantee it)



rotary pump, big honkin 19(?)cm turbine housing, and 3spd automatic...



previous owner's got pump turned up decently, and Glenn (remember Axekicker?) can haul 4 horses in the trailer pretty decently, but would like a more efficient transmission and, probably a 16cm non-w'gated housing.



transmission fluid runs about 275*F up a mountain, and the EGT and PSI are mentioned in the heading...



Still has stock exhaust, too. . thinking about full 4"



I think he's running so warm (EGT) due to lack of intake air... are he and I thinking right?---I don't remember if his has an intercooler, or if it's just a short snorkel.

 

[dusthomps]

If this truck is still stock and has a 3 speed auto, then it's not intercooled. EGT's sound about right to me. I can easily bury the pyro in my 91 going up a 5% grade. My truck also has a full mandrel bent 3" exhaust. Adding either a factory intercooler setup or an aftermarket along with the exhaust upgrade will bring the EGT's down. Hope this helps.



Dustin

 

[Midnite]

I think I'd be worried about those transmission fluid temperatures more than anything else.



Mike

 

[JStoll]

ditto on the trans temps a tad high

I could see the egts getting that high on a long hill pulling & its ok as long as its not shut down at those temps



sorta related I have been pretty suprized at peoples 900*+- temps that seems pretty cool my saab Ill do a wot pull in 5th or through the gears & pull over & my manifold tirbine housing & downpipe are glowing I havent taken EGTs on that but Im sure there fairly abusive gassers are hitting 1500* & yes thats on the hot side

but I am new to diesels so it may be verry diferent

one turbo guy was trying to explain a heat & eficiency thing to me he said the turbine has to hit 700* to work well this dident make allot of sence to me but I thought it worth mentioning

JAK

 

[BushWakr - RIP]

1250*F pre-turbo is the MAX temp for sustained running. Even then you'll need lots of cooldown time because the hot casting of the exhaust housing will hold heat longer than the area of the manifold were the pyro is mounted.

270*F transmission oil temp is way off the scale.

If it is a 93 transmission then it is an overdrive equiped trans. and it also has an intercooler.

The transmission has a temp sensor to monitor high temps. At approx. 270*F that sensor should signal the transmission to drop out of OD and into 3rd gear. It will also prevent an upshift to OD while the temps are that high.

At 230*F you are affecting the oil/lubrication package/stability... . at 270*F you are (rhetorically speaking) taking a chainsaw to the oil and, it's pretty much roasted after a few trips into that kind of temp.





Bob.

 

[bflood]

I've been told, and have read, that 1150* (pre-turbo) was kinda the upper "safe" limit for any lengthy amount of time. My EGT will not go over this at WOT if near full RPM but if my heavy load drags down the RPM some, maybe 2200rpm, (I'm guessing because I don't have a tach yet and haven't figured out rpm from speed & ratios) EGT's will run up to 1350* and I either have to ease up on the throttle a little or shift. If the RPM goes lower yet (with the pedal mashed) the EGT's will will start to "run away".



I've been chronically nagged by high EGT's on heavy pulls (I'm talking about climbing hills with a 14,000 to 16,000# trailer load) and I'm not sure what to do next. At this time I keep out of trouble by an attentive eye on the pyro gauge and driving accordingly. Even so, I'm always impressed with her awesome power.



I think maybe you're friend's next step should be a smaller turbo housing and better air filter. Also, some advance on the timing could help too.



Maybe some other more experienced bombers have better ideas on priorities regarding EGT's and I'll look forward to their suggestions.



Good Luck,

Bruce

 

[bflood]

Originally posted by BushWakr

1250*F pre-turbo is the MAX temp for sustained running. . . .

Thanks Bob, I stand corrected to 1250* (instead of 1150*). The first thing to go is the brain (they say).

Bruce

 

[rich m]

as we suspected!

He's made up his shopping list, and I guess he'd better add "Amsoil" ATF to it... . the transmission temp won't be significantly lower, but the fluid will be more forgiving... . he's also going to go with (at the minimum) a bigger-volume trans-pan, and an auxiliary cooler. If finance allows, he's likely to do an entire refurbished/upgraded transmission/TC from a place that he didn't name.





I'm personally looking (when finance allows) to upgrade my TC... BD's new one is good for 1300+ lbft and 2nd-gear lockup!! WOOHOO!!!!!

 

[BushWakr - RIP]

Ummmm... . this is one of those 'good news, bad news' kinda things here... ...



First if you go down in turbo exhaust housing size, say 18cm to 16cm then you can expect about 2-3 psi more boost but you'll also have slightly higher temps at the WOT/full load range. The 16cm housing is the best all around housing for a combo of towing/performance kinda thing. Either way, the smaller the housing the faster the boost and more boost, which runs outta air at higher revs. The larger the housing the slower the boost and slightly less boost, but better breathing at the upper ends.

A high flow air filter is a must, free flow exhaust is also recommended, a good fuel additive helps pump life.

Your are on the right track by "picking up" a gear as they say. When temps climb your gear should go lower, which in turn gains RPM and cooler temps cause the load factor is reduced.



Now the touchy topic... ... . Yup, transmissions..... more blood has been spilled over this one than you can shake a stick at..... HEY THERE's MY STICK... ... .



None of the 1st Gen trucks have/had a lockup transmission. NONE that I'm aware of, or ever seen.

Our trucks use fluid coupling only. It is weakest link in the system.

The TC's have a higher stall speed than they should. Even the last of the 1st Gen's (92. 5-93) had TC's that were not really designed to work with the Cummins.

Our engine "does it's job" between 1700 - 2500 RPM roughly.

Since we do not have lockup, you can either do a full conversion to a lockup system (quite pricey even compared to aftermarket systems for fluid coupling only) OR, go with the most efficient fluid coupling system/transmission on the market which suits your needs.

I'm biased in case you're wondering, as you can see in my sig at the bottom. My experience with the company is just plain outstanding, right up to and including last week when I had my 1 year service done... first class.



The 1st gen trannys all ran hotter than the later ones, partly due to lockup systems reducing heat build up.

Keep in mind that the higher you push your engine HP/Tq the more likely you are to move your "effective stall speed" on the TC up as well. (that's the point at which the TC prevents any more increase in RPM)You can actually "push right thru" your stock TC with a tweaked/tuned engine, even a 1st Gen.



Just let me finish (this too long post) by saying do the free stuff first. Try freeing up the airflow by opening up the airbox with some holes. (they can be protected with some stainless steel screen from a hardware store and some epoxy.

Run the largest housing you can based on your majority of driving.

eg: 18. 5cm highway, towing, altitude. 16cm all around with majority being city stop and go and some highway; 14cm light to light little or easy towing rarely etc.

Those are generalizations remember, your choice may be different.



Bob.

 

[JFitzgerald]

Originally posted by bflood

Also, some advance on the timing could help too.

Just wanted to "spotlight" this suggestion, because it's a good one.



After I first turned up the fuel on my truck, I had an EGT problem when trying to use the new power when towing heavy. Advancing the timing of the pump really dropped EGT's under those same circumstances - with no noticeable loss of power. The feel and sound of the engine improved too.

 

[rich m]

looks like I need to do some clarifying, as well....

... Glenn's truck is a 1st-Gen D-350 (I don't recall year, but, it's not an 89 or a 90)---hasn't been Dyno'd, so HP unknown, but, we both suspect the previous owner maxed out the pump output. . so we guess about 300-ish "at the crank"... don't know what's getting lost in the sloshomatic transmission, though... .



thought the "rule of thumb" was about 1peakpsi/10peakHP... if he's getting 300, shouldn't his boost be adjusted to about 30-ish?

the spoolup of the current 45 acres of housing just doesn't send a lot of intake air, at any RPM range



Mine's a 98. 4 12-valver that's been BOMBed to 254RWHP (w/original 12cm housing, BD 270HP injectors and the BD "off road only" plate)... . I don't want to go farther until I get a new TC behind the currently anemic potential "Killer B"



We've both got our own year's automatic... No e-brake for him, yet... I like mine a lot! (BD)



He's thinking to do the total-transmission thing, in order to have all the modern advantages (such as ability to use an exhaust brake)

 

[BushWakr - RIP]

I can't recall who it was that said this, so I'm gonna take the credit for it.....

"... . An exhaust brake on a non-lockup TC can be replaced by a far more effective and cost efficient system... ... . stick your hand out the window... "



So, if the goal is using an E-Brake, then lockup is the only real choice... . aside from converting to a 5spd.



Bob.

 

[JStoll]

that was pretty funny I was thinking something like that when I read the ebrake thing too

I think that he intends to do the total traney thing though

JAK

 

[BushWakr - RIP]

Based on my personal experience with the company of my choosing,(I'm hard to please) Call them and get ready to rock 'N roll cause they got this down to a science. .

Please remember, this is MY opinion and not the opinion or endorsement of/by TDR, nor based on any inside information.





Bob.

 

[rich m]

Originally posted by BushWakr

"... . An exhaust brake on a non-lockup TC can be replaced by a far more effective and cost efficient system... ... . stick your hand out the window... "

LMAO!!!



maybe drag a stick on the ground and call it the "new, improved hand out the window"?

 

[BushWakr - RIP]

Hmmmmmm... ... how about "Five Finger Brake" (providing you're not an amputee) or... "Pac 'O Sticks Brake"... ... . :-laf



See ya got your maple brakes, your oak brakes, willow brakes, pine brakes and oh ya,... lets not furget the fur brakes... .



... . I kinda howled when I heard it too..... :-laf :-laf...



Bob.

 

[Old Smoky]

"Pac 'O Sticks Brake"... ... .

LOL, That’s great.



Maybe for extra braking action one could drag a solid stick of steel. It might get a bit warm, but would wear longer that the wood! :-laf



Mike

 

[BushWakr - RIP]

Heck ya... that would work, you could even use ATF +4 since it handles heat better too... ... . :-laf :-laf. .



bob.

 

[dpuckett]

Yikes,

1350 sounds a little high for the 22 psi; my early 91 makes about 25 psi and I NEVER see 1300. This is at 6500-7000 ft. Might try the timing. I know I have one bad injector, so new ones would probably bring down the temps a little. My t-couple is in the manifold. Intercooler would help, along with a 16 cm housing. I have run 12 cms, but for towing, I think they are a little too restrictive at higher throttle/ boost loads. they are GREAT for running empty though. Keep in mind most of my experience has been at a mile or higher.



Daniel

 

[Old Smoky]

I don’t think my rig ever got that warm when I was around 22psi. Just for comparisons sake, I tried detuning my pump once just to see how it would drive, and at 30psi the EGT wouldn’t go over 1000* empty. Timing and air upgrades should keep him within the safe range.



Mike