7.2 L 300hp mod ?'s....

[bigthaw]

going to look at 2003 38 w/ 86k mi. reseller states Cat 7.2L 300hp engine w Allison 6 speed, freightliner xc chassis, modded but knows no details....
what do I look for???? many concerns...radiator size? overheating? exhaust temp...my guess is tweaked up to 330hp... should I pass? 1 owner unit appears to be in good nick....but haven't inspected yet...driven 135 miles in last month reseller states...should I have oil analysis?...who is the big Cat dealer on mid east coast of Fla? Was this just an easy $2000 Cat ECM program tweak??? or?... IS this a deal killer???...

[CountryB]

Get the engine serial number then call Cat and they can tell of any work they did to engine. When you say the engine was "modded" is that what the owner is telling you - or are speaking with sales agent?

It is not hard for Cat technician to change engine computer parameters to increase the horsepower. That would be an acceptable modification and Cat would have it in their records.

I would have an oil analysis done, but it will probably take t7 to 10 days to get the results. I use Blackstone Labs. https://www.blackstone-labs.com/
There is another place (something like) JLG that is often recommended too.

The big Cat dealership in central florida is Ringhaver (Ring Power) Florida's Heavy Equipment Headquarters | Ring Power

[bigthaw]

Thanks Mike, I'm going to try and get owners name....but only reseller so far..appreciate your answer

[FIRE UP]

Originally Posted by bigthaw

going to look at 2003 38 w/ 86k mi. reseller states Cat 7.2L 300hp engine w Allison 6 speed, freightliner xc chassis, modded but knows no details....
what do I look for???? many concerns...radiator size? overheating? exhaust temp...my guess is tweaked up to 330hp... should I pass? 1 owner unit appears to be in good nick....but haven't inspected yet...driven 135 miles in last month reseller states...should I have oil analysis?...who is the big Cat dealer on mid east coast of Fla? Was this just an easy $2000 Cat ECM program tweak??? or?... IS this a deal killer???...

bigthaw,
Not that it's a big deal but, the C-7 version CAT, (300, 330 and 350HP versions) did not appear 'till late in Oct of '03 and, was labeled as an '04 in all the chassis's that it was introduced in. The 3126 version had several years as a 275HP, 300HP and a 330HP. CAT has always been a bit tight-lipped about modding their engines performance. Cummins on the other hand, has allowed folks like BANKS to do almost whatever mod they wanted to.

There are chips such as the MP-8 that have been floating around for a few years that were aimed at many CAT engines. Some, have reported some success and, not too many issues. But, others, had lots of bells and whistles go off when the chip was dialed into its highest setting. That chip hovers around the $500-$550 mark and since our C-7 has done so well, without any mods for over 80K miles, I figure it's just not worth goofing around with a well running engine. Everyone's got to make their own decision. Good luck.
Scott

[tropical36]

Originally Posted by bigthaw

going to look at 2003 38 w/ 86k mi. reseller states Cat 7.2L 300hp engine w Allison 6 speed, freightliner xc chassis, modded but knows no details....
what do I look for???? many concerns...radiator size? overheating? exhaust temp...my guess is tweaked up to 330hp... should I pass? 1 owner unit appears to be in good nick....but haven't inspected yet...driven 135 miles in last month reseller states...should I have oil analysis?...who is the big Cat dealer on mid east coast of Fla? Was this just an easy $2000 Cat ECM program tweak??? or?... IS this a deal killer???...

My only thoughts are to the power to length/weight ratio, so at 38ft and at 10hp per ft., one might be happier with a min. of 380hp.

[CountryB]

Originally Posted by tropical36

My only thoughts are to the power to length/weight ratio, so at 38ft and at 10hp per ft., one might be happier with a min. of 380hp.

Where is this number/ratio coming from? Is 10 HP per Ft the "sweet spot" (between performance and fuel economy)?

I would think the more important ratio would be "HP to Weight" (HP/GVWR).

I'm at 12.5 HP per foot of length , but weight wise, I'm at .0114 HP per pound .

[tropical36]

Originally Posted by CountryB

Where is this number/ratio coming from? Is 10 HP per Ft the "sweet spot" (between performance and fuel economy)?

I would think the more important ratio would be "HP to Weight" (HP/GVWR).

I'm at 12.5 HP per foot of length , but weight wise, I'm at .0114 HP per pound .

It kinda comes from making it over the hill without being in low gear, so to speak. It is all about moving the weight, but with the 10hp/ft ratio, it's just easier with one look at a coach and the weight usually goes with the length, for the most part. Some might say that this is the min. and would like having more, so as to be a mountain king.

[bigdog]

So then with a formula that I've never heard of and neither has my CAT dealer, it would mean that my Tradewinds at 40 feet is underpowered 70 horsepower. I have the 330 CAT turbo which can be kicked up to 350 horse, but have never heard of the 3126B chipped to 400 horse.

[tropical36]

Originally Posted by bigdog

So then with a formula that I've never heard of and neither has my CAT dealer, it would mean that my Tradewinds at 40 feet is underpowered 70 horsepower. I have the 330 CAT turbo which can be kicked up to 350 horse, but have never heard of the 3126B chipped to 400 horse.

The best approach, would be to leave it alone, as long as you're happy with it. Smaller trannys can be a weak link, as well, especially with the GCWR rating.
We're at almost 41ft, actually and the C9 400HP develops 1150ft lbs of torque @ 1400RPM, connected to an Allison 3000 for keeping a good 32000 lbs of weight moving. I cruise at 1500 RPM at about 57mph and It's all we need, with staying in 6th gear overdrive over hill and dale. Dropping to 5th overdrive will climb steeper terrain and dropping into 4th, is pretty rare.