Engine/Transmission (1998.5 - 2002) Mountain Towing High EGTs

[BCobain]

I was out on a trip this past weekend towing my rock truck (5500lbs max load). I was towing up Berthoud pass (11,000 ft) and I noticed my egts would climb very high at rpms above 2750 or so. I would only get a little spike before I shifted then they would cool back down. There is about 7 switch backs up each side and it would only get high egts at the top of 3rd gear (1400). I would shift into 4th and they would calm down even at wot (<1200). My truck is stock as far as fuel and boost. I added a 4" turbo back system and a BHAF. My gauge is a procomp ultralite.

My question, is this normal and I just need to learn how to drive a real truck? Is my gauge poopy?



I've searched and not really found much to help. From what I've read the edge ez will help my milage and lower my egts? Or is the only real way to drop egts is to get less internal turbo restriction?

 

[SEmerson]

You must be just running out of air. Never pull over 1250 temp for very long you could melt a piston. You should have the best power at 2000-2200. So just run where the temp is ok. I run the best at 3 gear for egts on hills (I have a auto). If I lug I get hot.

 

[AKAMAC]

First, Welcome to the site!

Think of the engine as a compressor with a limited amount of air on the intake side (wastegate). At 2700 rpm under load there is a cut-back on boost. Fuel continues but air is lessened. At 2700 with the hx35 turbo under load with a boost elbow you would see 35 to 38 psi, stock you will only see 20 to 26. Less boost = more heat at peak fueling.

Now fill out your sig so we know what year, model, and stuff on your rig. (IE) Do you have a boost gauge?

Mike

 

[BCobain]

Yea my boost never goes above 22psi, I hope to get an EZ with an elbow, I've heard that will get me 30lbs. I didn't get above 1400 more then 2 seconds each time and right when I would shift they would drop below 1200 and stay there. So I should just shift early to 4th and stay below the 1250 mark all the time? or is 1350 ok for less then 4 seconds? Thank you for the replys and this site rock with good info.



I'm a goob do I have to enable my sig?

nm there it is

 

[Sticks]

Getting closer on the sig, but I am still confused if you have an auto or manual. If manual, 5 or 6 speed (SO engine or HO).



Edge EZ on a SO engine, good for towing up hills.

Edge EZ on an HO, BAD PLAN for towing up hills.



For a stock truck you sound like you are right where it is supposed to be. Berthod pass is something like 12k feet at the summit, NO AIR UP THERE!



Any type of box with a boost fooler will certainly help you out.



Another option is a Water/Methanol Injection set up. That will certainly help cool the EGT's (200+) and no harmful side effects.

 

[Hohn]

Another option is a Water/Methanol Injection set up. That will certainly help cool the EGT's (200+) and no harmful side effects.

Well, yes and no. There is a POTENTIAL problem, but it's one that exist in theory mostly, and it's not occurring based on reports from water/meth users.



Namely, detonation. Typically a diesel ingests only air, thus no risk of detonation (aside from messed up timing).



But when you add the water/meth, you are adding to the intake a COMBUSTIBLE MIXTURE! That means that you could light off the meth before the actual point of injection-- thus detonation.



Like I said, I haven't heard of this happening, so I bet that it's not. But it is a very real possibility.



Moreover, at high altitude your engine isn't seeing as high a peak cylinder pressure (before injection) for a given boost level, so the liklihood of setting off the meth is lower.



If you aren't comfortable with the meth, water injection alone should net you some improvement in high altitude towing.



Justin

 

[BCobain]

Sorry, I have a NV4500 ETC, I guess I more amazed that Cummins would allow such high EGTs in a stock fuel trim vehicle. I've towed before Gauges and exhaust, I hope I didn't do damage.



On the wather/methanol injection, is the methanol used as a power adder? Methanol is a combustable, and fairly volatile (sp). And if I'm on a road trip I'm not sure where I would get methanol. I guess just water injection would work. I need to read more about this though.



Thank you for the response, I'll just have to be more careful at altitude.



Brian

 

[Forrest Nearing]

methanol increases cylinder pressure...



just inject straight water for EGT help.



Forrest

 

[Sticks]

A 50/50 mix of water and meth is about as far as the 12 and 2nd gen 24 valves can go before the problems start. It also does not cool as well, because as stated above, you are adding fuel.



Straight water will work great for EGT cooling (better than a 50/50 mix), but I believe that a modest mix of meth (25%) works better than the straight water. Now I do not have any concrete proof of that, but my last trip in the mountains showed better results with a low mix versus straight water.



As for finding meth on the road, windshield washer fluid. It's blue, and the warning label will say "CAUTION - contains methanol... ". Not all washer fluids will have it, you just have to read the label. Some are an alcohol mix, I think Methlalcohol (sp). It must read methanol. Also the yellow HEET for gassers, but it can get REALLY expensive.

 

[Forrest Nearing]

a mix will cool better than straight water, but straight water won't increase cylinder pressure... a mix will... if you're not on the ragged edge of your head gasket, go ahead and run some methanol.



Forrest