X15

[tsolson]

Hi
I’m looking at a couple different trucks, and I’m just wondering what the differences are between the X15 Performance series, and the Efficiency series. Is it just HP rating, or are there different parts etc. and which one is better, or more reliable?

Thanks

[Bengy88]

Sounds like an interesting subject, the economy series is usually 400ish hp. It’s usually attached to an automatic transmission and has 260 rears behind that because they are bought by companies like j.b. Hunt, Ryder, Werner, swift, and Penske, they get 500-700k put on them and then are sold to guys that swear they got a good deal because they bought a lugged to death 500,000 mile truck for 50,000$. And on top of it you really don’t see a gain in mpgs because the transmission is driving the truck for you and shifting at 12-1300 rpm’s so either engine you look at is still gonna get 6.5 ish mpgs. It’s a complete waste of money in my personal opinion. The performance series usually…. Usually is a minimum of 535 hp to a max 635 hp factory and could be in any truck with any transmission and any rears and would be bought by anyone except these big companies. The way I see it if you want a 400hp engine why waste the money on a 15 liter?

That may not answer your question but at least now you have an opinion. Whether it’s a good one or bad one lol.

[Rawze]

(03-14-2020 )Rawze Wrote:  What is actually same ...
----Overhead cam =- same
----Connecting rods =- same
----block =- same between the Efficiency and Productivity series.
----crank =- same between the Efficiency and Productivity series.
----injectors =- same
----Intake valves on head =- same

What is actually different ...
----head =- different (due to different exhaust valves only)

----pistons =- Performance AND Productivity series has the different (due to slightly different compression ratio) than the efficiency series.

----block =- Performance series has Slightly shorter and heavier than the one used on the Productivity/efficency series engines.

----crank =- Performance series has Slightly shorter and heavier than the one used on the Productivity/efficency series engines.

reference: http://rawze.com/forums/showthread.php?t...0#pid51650


-- I.E.> They have different hard parts (at least they did when I looked them all up on quickserv back then).

=============

And if your looking at truck purchases these days, like bengy88 roughly said,... its very difficult to find a truck that has not been lugged to an agonizing death below 1500RPMits whole life, and ready for an inframe by the time it gets to 500k miles on it.

All the mega-fleets are gearing their trucks these days way too tall so that they cannot produce full horsepower (in the name of saving a bit of fuel, directly at the cost of the engine longevity) and this cuts engine life essentially in half. - They don't care, because they get rid of that truck at or before that point, and then unsuspecting single truck O/O's will come along or a used truck fleet and buy them up with the false assumption that it still has half a million miles left in it, only for it to plague them and make then go out of business.

(the beer is talkin')...
- God bless all those big-fleet corporate bean counters and spread-sheet warriors who figured all this stuffs out. Its so common now that someone is hard pressed to find a decent used truck that isn't more than 8+ or 10+ years old and actually spec'd right for someones operations. They are rare any more. Ask one of these moron spread-sheet warriors how they sleep at night, and they would be proud to tell you that they saved their company millions of $$$$ with those wacky ideas and be all proud of it and s#it.

Go ahead and try to find a newer model mid-tier truck with an X15 in it and a decent set of rears, 3.55's (or better yet, 3.79's maybe 3,90's) + a manual 13-speed (or 10-speed) tranny in it that has been well cared for those first half-million miles.
Here is he typical scenario: http://rawze.com/forums/showthread.php?t...2#pid37802

[tsolson]

(09-03-2023 )Rawze Wrote:  ...
Go ahead and try to find a newer model mid-tier truck with an X15 in it and a decent set of rears, 3.55's (or better yet, 3.79's maybe 3,90's) + a manual 13-speed (or 10-speed) tranny in it that has been well cared for those first half-million miles.
Here is he typical scenario: http://rawze.com/forums/showthread.php?t...2#pid37802

It’s definitely hard to find anything with proper rear diff ratios. The first truck I looked at had 2.60 rears and I had to ask twice cause I thought I heard him wrong. Lol

I have a couple 2018 Kenworth’s I’m going to look at tomorrow that have X15 and 3.91 rears, 18 speed manual trans. They have around 400,000 miles. From what I’m reading here, I’ll definitely need to replace the fuel pump or plan to asap if I buy one? I knew the previous models were bad, but I assumed they had hopefully fixed the issue with the newer engine. Anything else that I need to watch for ?

[JimT]

(09-03-2023 )Rawze Wrote:  ...
Go ahead and try to find a newer model mid-tier truck with an X15 in it and a decent set of rears, 3.55's (or better yet, 3.79's maybe 3,90's) + a manual 13-speed (or 10-speed) tranny in it that has been well cared for those first half-million miles.
Here is he typical scenario: http://rawze.com/forums/showthread.php?t...2#pid37802

This reality is why I've decided any future business expansion I do with used trucks will be older trucks with the right specs. Ideally that the owner is selling cheap because they know it's due for major work. The way I look at it an older $10,000 truck that needs $40,000 is maintenance is probably a better investment than one of the aforementioned newer trucks being sold for $60-80k and they are typically easier to work on due to less computer integration. New would be my next choice but the current prices are outrageous and the overall reliability doesn't look very good. Not to mention the volatile evolving environment with engine/emission regulations right now. While I believe electric vehicles will be the future, it's still a LONG way off before they become a VIABLE alternative to most trucking applications. While I'm optimistic about what Edison Motors is doing with their diesel-electric hybrid trucks, they don't currently appear to be interested in applying that to the on-highway long-haul applications that see mass production and use. (I don't understand why this option was not seen until recently as a viable intermediate step in the truck electrification initiative as it alleviates many of the concerns with electric trucks. But that's getting too off-topic here)

[tree98]

(09-04-2023 )tsolson Wrote:  I’ll definitely need to replace the fuel pump or plan to asap if I buy one? I knew the previous models were bad, but I assumed they had hopefully fixed the issue with the newer engine. Anything else that I need to watch for ?

If it's a dual line pump (2 lines coming out of the pump head) you probably don't need to worry much about it. Mr Hagg said they don't see the same problems with those like they do the single line. It's a good thing too because you can't buy parts for the dual line pumps, you have to replace the entire pump for about $6K.

I have a performance series X15 and it has the dual line pump. I'm not positive but I think they only come on the performance series.