The Inline 6 is making a comeback, baby!!! - Page 2 -
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post #16 of 20 Old 12-29-2018, 02:00 PM
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Fiat R&D new I6, LOL...... what could go wrong TONY?

hard to compare power say from the mid 70s and 80s to things made in the 90s. even the V8s made in the mid late 70s hardly made 180hp. were say in the early 2000s some 4 bangers stock had 300+hp. None were very reliable as well. Displacement tends to make longer lasting power then say 4 squirrels getting blown by a hooker.......

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post #17 of 20 Old 12-29-2018, 07:26 PM
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If you cannot fix it with a hammer then it has to be an electrical problem.
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post #18 of 20 Old 12-31-2018, 11:14 AM
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Originally Posted by TheBoogieman View Post
Who? That engine was so gutless that my old 2.5L put out more HP.

Boogie, you are making my point.
What is the design goal of an engine? It depends on who you ask.

You didn't like that engine because it did not make much horsepower.

Some other design options:

Safety (doesn't catch on fire or explode - Fiero)
Reliability (Starts when needed and keeps running)
Economy (Gas Mileage)
Air Pollution (no catalytic convertors, but did have air pump)
Torque (one half of the horsepower equation)
Maximum RPM (the other half)
Strength (i.e. no cracks in block)
Ease of manufacture
Ease of repair (i.e. if something serious breaks)
Ease of upkeep (i.e. oil changes, spark plugs, etc)
Government Compliance (CA, then everywhere else)


Looking at this list you can see it is easy to pick one or two, or maybe three items and say, "Concentrate on these".

Because this engine was in service for so many years, the engineers were able to optimize almost every aspect of it to come up with the engine in the '06 TJ. I expect they would still be working on it if the bean counters had not decided to use a V-6 that is probably cheaper (always the #1 issue with bean counters!).

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post #19 of 20 Old 01-03-2019, 10:56 AM
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Really, the only thing I miss about the 4.0 that was in my TJ is the torque. You gotta have that 3.6 Pentastar singing to get into the torque curve. I'd just as soon have some low-end grunt.

Of course, I'm not going to swap in a 4.0 when the time comes. Mrs. Doubtfire is going LS, baby.

I will fight a bear
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post #20 of 20 Old 01-27-2019, 05:44 PM
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I always thought a good upgrade to the old inline 4.0 would have been a crossflow head, to improve breathing. They are a long lived engine except for the cyl head cracks that affected certain years (2000-2004 I think?). The Pentastar is nice but a lot more complex, with OHC and variable valve timing. Changing plugs on those is a big job involving having to remove the intake manifold. But they do run great and put out good power.

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