Who's turning their stock bottom D-Max's 5k?

[IDRIVEAG8GT]

Like the title says, who's shifting at 5000 rpm, and what all did you do to support it?

-Robbie.

[MikeOD]

Like the title says, who's shifting at 5000 rpm, and what all did you do to support it?

-Robbie.

Probably going to need a LOT more turbo to make that much RPM worth it.

[IDRIVEAG8GT]

Probably going to need a LOT more turbo to make that much RPM worth it.

I was figuring that, I'm just following up as I read from many different shops that you could run up to 5,000+ rpm on a stock bottom end D-Max with fantastic results.

I'm trying to get into the Diesel stuff now as I've pretty well learned gas stuff. I personally really want a Duramax, and a friend of mine is getting one soon as well that he wants tuned.

[ajamesbond007]

The engine can take it, but like MikeOD said, going to need a lot more turbo. Also, another thing to consider, shifting (if you want to shift at the RPM) is hard to do for the stock allison. More usable power can be obtained in the factory RPM range, shifts will be quicker, and EGT's won't be a nightmare like they would in the 5k. Don't get me wrong, 5k in a duramax is quite a sight and the sound is heavenly. If you want to rev that high, you will need to command torque up to those levels, as well as raise your full throttle shift rpm. There might be some other limiters that I am unaware of at this point, but that should get you pointed in the right direction.

Happy reving!

[IDRIVEAG8GT]

Turbo, no problem!

And I have an Allison nerd right here in town when it comes to transmission specialties.

Can you give me a quick tutorial on how to command torque at that high of rpm?

I read your suggestions about tuning thoroughly and from what I can see it seems like most of the tables end at 4,900 rpm.

Also with super high EGT's what else do you have to worry about except for the turbo? I imagine you just dump fuel to it to get the EGT down?

[ajamesbond007]

Let me check and will post within 15-20 minutes

[ajamesbond007]

General - Exhaust Brake (Stock 4200) : Never seen this in effect. Might not be a bad idea to max this puppy out

Fuel - Diesel - ""Middle Column"" There are some limiters in here. I haven't had time to look through all of them and figure out what exactly each one does. I'll get you what I know first, then we will try and tackle these. ALSO, need to look at timing tables to make sure that we won't blow anything major. Like I said, I'll get to the main stuff first.

Torque Management - Engine - Driver Demand : Open this table up. Here is all the command torque values vs TPS. As you can see, 4800 is carrying a negative sign on those torques, better get rid of that. Use a value around 450-500 for TPS 70% and up and from 3000 rpms and up to 4800.

Torque Management - Engine - Peak Torque : Need to change this according to the values you put in the driver demand so you are not limiting torque.

Torque Management - Turbocharger : Here are all the turbo tables. Find out if your EGR is blocked and use the appropriate tables. Don't worry about the others (if yours is on, don't even worry about the off for now) Being in New Mexico, probably only need to adjust the LOW tables for now. Good practice to adjust all the tables incase you go up in altitude. (PS - LOW means low altitude and High means Hi altitude. HP has the description backwards) For reaching your 5k rpm goal, you won't need to adjust these, but this is good reference of future tunes.

[ajamesbond007]

Still posting

[ajamesbond007]

Trans tables

Pretty simple as I know you have lots of experience with trans tuning in gassers... (If I am ever in New Mexico, I should get a free ride in that '8 of yours... just saying )

Leave T/H or performance alone for now.

-Need to change part throttle and full throttle shift speeds (might one to only change one gear for now to see if it works)
-Need to change full throttle RPM
-Leave shift properties and general pressures alone. Very different from the 6L80's

-To save your converter, lets set it not to lock up anything above 50% in throttle. In all gears, anything above 50%, max out. No need to put extra stress on anything.
-Also do the same for WOT lock up, max out. (Word of caution - watch the tranny temp gauge. You probably already know this, but never hurts to say something)
-Torque Management - General TCC Limit - This is why we don't want it locking up. This is also a possible limiter, and the reason we want to make sure we aren't limiting torque and scratching our heads why we can't reach it. We need to make sure we are commanding torque out in the 4800 rpm range. Similar to the Driver demand, we see negative values. better changes those similar to the Driver Demand.

[ajamesbond007]

Now, here are my suggestions. I would only try getting the RPMs to the stratosphere in neutral. If you want to driver it that way, fine, but lets limit the upshift. You can do it one in two ways.
1) use manual mode, put it in 3rd. Let it shift into 3rd, and only when you know its in 3rd, try it out and see what happens. Do not let it shift into 4th unless you are under 4k. There is a lot of heavy mass spinning faster than what is was designed for from the factory. built trans clutches can handle this, yours might limp if you try to shift.
2) tune the WOT and Part throttle shift speeds so it never sees anything above 3rd.

Your call which route you want to take. Whatever you do, make sure it doesn't shift. If you have any questions, let me know.

IF you get there, wouldn't mind a video of the act in progress

Happy Reving!!!

[IDRIVEAG8GT]

Fantastic! Thanks so much! It's going to be another fun build, and definitely you'll get a ride in the G8, and in Gray Ghost too. It's my 1067rwhp...... ahem...... work truck

[ajamesbond007]

I read your suggestions about tuning thoroughly and from what I can see it seems like most of the tables end at 4,900 rpm.

Also with super high EGT's what else do you have to worry about except for the turbo? I imagine you just dump fuel to it to get the EGT down?

Forgot to answer these parts. On the first point, not sure actually lol. I am sure 4800 is pretty close to your 5k mark. On the second point, super high EGT's will ruin your engine. Valves, heads, pistons, basically everything inside the combustion chamber says "I hate you" lol. Anything above 1300* IMO is getting too hot. You CAN hold above 1300* for a short duration and be fine (not sure how long before we get to damage, but I have always said to customers without a pryo for not any longer than 5-8 seconds). I have *heard* of pulling trucks holding 15-1600 for the length of the track, which is roughly 10-15 seconds, but they usually have built internals as well.
Ironically, dumping fuel does the exact opposite (except when you tune for pulling, then you gain a protection factor, but it is pretty rich) Due to the nature of diesels, more fuel will generally yield higher EGT's. More boost *lowers* EGT's. That's why you hear people who run smoke tunes all the time ruin their engines. High EGT's wear the parts, gunks up the engine, and just puts it through hell.

[ajamesbond007]

Also wanted to add this to your research:

http://www.hptuners.com/forum/showpo...67&postcount=2

Read those articles will give you a base on what to start. When playing with timing, DO NOT CALL FOR MORE THAN 30* OF TIMING (I would even be more hesitant and say not to command more than 20* as my tune runs less than 20* and puts power down well).

[ajamesbond007]

Fantastic! Thanks so much! It's going to be another fun build, and definitely you'll get a ride in the G8, and in Gray Ghost too. It's my 1067rwhp...... ahem...... work truck

And that ^^^^ is totally awesome! I will gladly take that offer any day

[ajamesbond007]

I now understand why you want to get into the diesel business

http://www.g8board.com/forums/showthread.php?t=54607