Performance diffs between a built 4.0 and a stroker

Thats about it...what would the diffs be between a 4.0 with performance parts, and a 4.7 stroker? Good side and bad of each would be nice
Thanks,
Dave

Do you want power or do you want Lots of power? Its all a matter of how much you can spend and how much power you want. Not sure theres a difference in which one will be better since they are both the "same" motor with the execption of the crank.

AARON

trouble1 said:

Thats about it...what would the diffs be between a 4.0 with performance parts, and a 4.7 stroker? Good side and bad of each would be nice
Thanks,
Dave

Click to expand...

No comparison - a 4.7 will have gobs more torque than a 4.0, even with a cam, lifters, injectors, etc.

4.0 Good:
Plenty of power. Not enough you say? Buy some axle gears.
Off-the-shelf parts

4.0 Bad:
Work involved for significant upgrades is two steps from stroker
Electronic upgrades will require premium fuel

Stroker Good:
More torque/hp - who the hell needs axle gears?
Fuel efficiency (possibly)
Fresh, New rebuilt engine top and bottom

Stroker Bad:
Setup costs
Custom internals
Tuning time/costs
Not able to give it to any old mechanic (not that you would anyway w/ a 4.0)

Not trying to bash a built 4.0 - But when my 4.0 goes, I'll probably stroke it - I wouldn't spend all the effort rebuilding a 4.0 just for a different crank/cam and ported/milled top end. If you're going to that kind of trouble, stroke it while its in pieces.

As for "chips" and forced induction - they require premium fuel.

I'd rather $hell it out up front on a well-built naturally aspirated stroker than at the pump for the next 200,000 miles.

I have a 4.0 with all the external bolt-on performance mods and a ported/milled head so I've almost maxed it out performance-wise. The only things left are to install a performance cam and mill the block deck to increase the CR even more. Since the engine has done 172k miles, I decided to build a 4.6L stroker in my spare time (out of a junkyard engine) and I'm going to swap that in when it's done instead of ripping apart my existing 4.0.
Pro's and cons of each:

Built 4.0:

Pros: Bulletproof, lots of torque but peaks too high in the rpm range (3500-4000), pulls hard to redline, fuel efficient (20+mpg routinely).

Cons: Gearing too tall to make full use of the engine's potential, only a 4.2 crank/rods away from a stroker.

Stroker:

Pros: Bulletproof (if built carefully), tire-shredding torque at lower rpm, HP/TQ and powerband ideally suited to 3.07 gears and stock tire size in 5-speed XJ, freshly built new engine, fuel efficient (virtually same mpg as 4.0), simple stroker costs little more than stock rebuild.

Cons: Can be expensive if you use custom forged pistons/Eagle forged rods/Big valve head, produces more heat than 4.0 so cooling system upgrades needed, time needed for engine computer to adapt, fuel curve needs to be modified (oversize injectors +/- MAP adjuster or adjustable FPR).
_________________________________________________________________
- 1992 4.0 XJ Laredo UpCountry with modifications - 172k miles - AX15, NP231, D35c, D30
Estimated 240hp@5250rpm/280lbft@3500-4000rpm, 1/[email protected], race weight 3465lb
- Future mods -
4.6L stroker (under construction)
- Websites -
Jeep 4.0 performance, 4.6L stroker build-up
- Tech Webpages -
CTS resistor trick, Dual electric fans, IAT sensor relocation, Intake manifold heatshield, MAP adjuster, Oil temp. gauge install
- Info Pages -
Automotive formulae, Jeep 4.0 cam specs, Jeep engine dyno graphs

All I can say is that i love my stroker. Wouldn't think of going back. It is a joy to drive and the gas mileage is as good or better than before......if I can keep my foot out of it.