First Post---1998 4700LPX and a couple questions

[ybyrental]

Sorry....not too big of a computer guy. I'm pretty vanilla overall.

Our little work truck:
1998 4700LPX
7.3 175HP
Allison AT543

We're a small equipment rental company, and the majority of our deliveries are within 25-30 miles....although we do make longer runs for some or our regular customers. I've had this truck for around 8 years, and have kept it stock. Definitely pretty slow; definitely highly reliable and durable. We constantly pull anywhere from 15k-40k with it....and it never complains. I could never find any simple modification for this truck--years ago, there was a chip that I believe fools the ICP into delivering more fuel with claims of up to a 40HP increase, but I never felt a bit of difference.

I came across the Orion Flash System more or less by accident when I was looking for something else online, but after a little investigation, I figured it was worth the gamble to try to just get a little bit more towing power. I only recently installed it, and have only used it on the 4th level(I believe 230HP), and all I can say is WOW....it's worth every penny. I really don't want to compromise its reliability, because it has been a dynamite truck, so I don't know if I'll do much more. This alone has been what I've been looking for over the last I-don't-know-how-many years.

I do have one question, as I'm not a big computer or tuner guy---Will the parameters allow me to change the factory governed RPM? I believe it is set at either 2700 or 2800RPM, and I was looking to go may 75-100 more....so I can travel at 65MPH while hauling? Or is this a no-no.

Thanks, Kevin4700lpx1.jpg

[Power Hungry]

In order to change the Rev Limiter, you need to connect to the vehicle and open the Orion software. (Please see attached image for reference)

1. From the Orion Dialog, select [Parameters] -> [View/Edit Parameters]
2. From the Parameters Dialog, select [Parameters] -> [Read Parameters]
3. In [Parameter Blocks], scroll down and select Block [82 - Engine Family and Transmsission]
4. In [Parameter Levels], select Parameter [003 - High Idle Engine Speed]
5. Enter the desired RPM in the [Modified Parameter Value] box
6. Select [Parameters] -> [Write Parameters] to change the value in the ECM
7. Close the Parameters Dialog
8. Follow Key Cycle procedures as requested by the software

The new Rev Limiter should now be set and you can disconnect.

If you have any questions, please let us know.

[Jackpine]

And, Bill - just to set Kevin's mind at ease, increasing the rev limit by his proposed 100 RPMs is safe, correct? I'm sure it is, or you would not have told him how to do it.

- Jack

[ybyrental]

Thanks, guys. Just trying to keep it in a pretty safe mode.

I did have a boost gauge prior to the Orion, because we were curious if we were losing any power over time. When it has always been underpowered, it's easy to think that you are even losing more. From what little information I did gather, the general consensus was about 17psi under max load in stock configuration? I was getting around 16.5psi, so I figured that we were still getting full output.

Now---foolish me....I put a 20PSI boost gauge in the truck, not knowing that your reflash kit existed. Like I mentioned, I'm running at power level 4, and it obviously goes beyond the 20PSI max reading. If I was guessing, maybe it maxes around 22-23PSI at this level? A higher boost gauge is on its way. I also put in a pyrometer, and so far, my max temp on my heaviest pull has been around 1050 degrees.

I figure I'll stay at this power level until I'm confident my most heavy hauling doesn't send those temperatures much higher. But if you were to guess, how much higher EGTs could I expect going up one more power level? How much higher boost pressure?

[Power Hungry]

Originally Posted by Jackpine

And, Bill - just to set Kevin's mind at ease, increasing the rev limit by his proposed 100 RPMs is safe, correct? I'm sure it is, or you would not have told him how to do it.

- Jack

Yes, 100 RPM on that engine won't hurt anything. It's basically a 7.3L like the Ford Power Stroke, and they run up to 3800 RPM. The Navistars are limited to 2700 RPM. Even bumping to 3000 (+300) RPM is perfectly fine.

Originally Posted by ybyrental

Thanks, guys. Just trying to keep it in a pretty safe mode.

I did have a boost gauge prior to the Orion, because we were curious if we were losing any power over time. When it has always been underpowered, it's easy to think that you are even losing more. From what little information I did gather, the general consensus was about 17psi under max load in stock configuration? I was getting around 16.5psi, so I figured that we were still getting full output.

Now---foolish me....I put a 20PSI boost gauge in the truck, not knowing that your reflash kit existed. Like I mentioned, I'm running at power level 4, and it obviously goes beyond the 20PSI max reading. If I was guessing, maybe it maxes around 22-23PSI at this level? A higher boost gauge is on its way. I also put in a pyrometer, and so far, my max temp on my heaviest pull has been around 1050 degrees.

I figure I'll stay at this power level until I'm confident my most heavy hauling doesn't send those temperatures much higher. But if you were to guess, how much higher EGTs could I expect going up one more power level? How much higher boost pressure?

With the moderate tuning, you should see 22-25 PSI. That's perfectly normal. Also, 1050 on the Pyro is great. Anything under 1150-1200 sustained under load is fine.

Hope this helps.

[ybyrental]

I appreciate it.

Once you get the taste of something, you always want a little more....