My Dmax EGTs

[Mogman]

I was asked about the EGTs running a 475HP tune on another thread but did not want to hijack that thread so here is my answer.

I could easily push them into the 1400s with the 475HP tune,
With the 365HP tune and busting a 30-35mph head wind (20-30 is VERY common down here on the Coastal Plains) I am running around 1200-1250@75-80MPH which is starting to get uncomfortable so I normally back off until I get under 1200, the Duramax normally runs a higher EGT than say the 6.5L.
1350-1400 is considered MAX for any length of time and up to 1800 in the 1/4 mile, any of those numbers would likely immediately melt the 6.5L but are OK for the Duramax.
Normal cruising without a strong head wind I run around 1000-1050@75-80MPH (my normal cruising speed) the wind makes a big difference, down wind I often see 900 or so.
Just 3-4MPH can make a big difference.

 

[MarkM]

Yeah 1400 for a bit of time is rolling the dice. What's the max RPMs on the Duramax? My son has a 2003 5.9 and he tries to keep it under 3200 RPMs but it will obviously go higher.

Mark

 

[Mogman]

It is governed at 3450 under load and 4800 max braking, so at least valve float is not a problem at 4800.
I have read several accounts where folks push them to 4500 with no apparent issues, but POWER/VS/RPM really starts to drop off at 3700 or so.
I have not worked out the numbers but I have the speed limits removed from my tune and have seen the 120 MPH GPS speedo stop at 120 MPH (will not go any farther) I did not think to look at the tach, things were getting a little exciting with no top or doors.
Actually I just worked out the numbers and 120 MPH would be about 3375 RPM.

 

[MarkM]

120 in a Hmmwv must be wild lol

 

[Mogman]

120 in a Hmmwv must be wild lol

It was not bad, it did not do anything scary, I have been allot faster on scooters back in the day, the only thing crazy or maybe stupid was I still had the original 1993 tires on it.
But I had just built it and wanted to see what it would do but had not changed the 3450RPM gov, so it would have topped out at about 122MPH
I never claimed I always make wise choices.
I did blow out the two aftermarket CV shafts boots, but anything above 85 or so does that, I have had no issues with factory CV shafts or aftermarket shafts with factory boots.

YOLO

 

[MarkM]

It was not bad, it did not do anything scary, I have been allot faster on scooters back in the day, the only thing crazy or maybe stupid was I still had the original 1993 tires on it.
But I had just built it and wanted to see what it would do but had not changed the 3450RPM gov, so it would have topped out at about 122MPH
I never claimed I always make wise choices.
I did blow out the two aftermarket CV shafts boots, but anything above 85 or so does that, I have had no issues with factory CV shafts or aftermarket shafts with factory boots.

YOLO

I thought HMMWV tires are "Z" rated. LOL

Blow out

 

[Mogman]

I thought HMMWV tires are "Z" rated. LOL

Blow out

That was not a blowout, the truck was hit by a car that ran a stop sign.