so how much power does your stroker have?

[Bouncy]

My stroker is very quiet...sitting on the engine stand till I get time to install


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Forsale: 4.2 Crank and Rods for stroker build...Also 99 Intake ported...see link for details http://www.naxja.org/forum/showthread.php?t=900424

 

[Dr. Dyno]

Dynos should only be used as a tuning tool. The numbers will vary by dyno manufacturer and vary from dyno to dyno. Comparing dyno numbers accross the world is pointless IMO. The only reason I care to dyno my jeep is for AF ratios, I would like to see what it looks like.

Agree that dynos are more useful as a tuning tool than anything else. They're also useful at comparing HP/TQ figures (on the same dyno) before and after doing mods. As far as using the absolute HP/TQ numbers go, you'll get variations from dyno to dyno so you can't read too much into those. What a dyno run will tell you regardless of numbers is the shape of the torque curve and at what rpm you're getting peak TQ and HP.
The Dastek Dyno that I used can work in two modes.
Firstly, It can be used as an inertia dyno where you just accelerate at WOT across the rpm range while the dyno measures the rate of acceleration, computing the TQ and then, from the engine rpm, the HP.
It can also be used as a load dyno where you hold the throttle wide open and the dyno loads the wheels to maintain a steady roller speed (and engine rpm), measuring TQ and deriving HP at various rpm in 500rpm increments. In that mode, it can be used to map the fuel and timing curves on a programmeable chip.
Dastek also manufacture the Unichip and their dyno is very useful for programming it to each individual vehicle's needs.
When I dynoed my Jeep, I found out that my air/fuel ratios were very close to the desired 13:1 at WOT so I was happy I had my MAP adjuster correctly set at 5.1v.

 

[JJacobs]

Dynos should only be used as a tuning tool. The numbers will vary by dyno manufacturer and vary from dyno to dyno.

That's a bunch of hooey. Barring any trickery by the dyno operator, I would think any two chassis dynos in the world should show the same vehicle to be within about 25hp. Dead even-no. Accurate enough to tell you if your combo is rocking or sucking-yes.

 

[BlueCuda]

Well, then there must be alot of trickery going on lol. Mustang vs Dyno Jet Vs Other all read somewhat different. May not vary by 25hp on lower HP like ours jeeps but for sure on the high numbers. Things like Torque converter stall and other things help make the numbers even less accurate. But repeatability is all your after when using a dyno to tune. Same goes for Engine Dynos as well, they all vary somewhat because of make and model and operater preferences.

Best Dyno? 1320 of smooth pavement and a wideband monitor. They can try all they want but a pair of 5000lb rollers will never match the real world.

 

[Dr. Dyno]

You've forgotten another reason for variation in HP/TQ numbers between dynos, and that's the HP correction factor used.
The most common are the SAE standards. The older J607 standard considers that the engine was run on a 60°F day with 0% humidity and a barometric pressure of 29.92 in-Hg, and the newer SAE J1349 standard of 77°F (25°C) day with 0% humidity and a barometric pressure of 29.234 in-Hg (99 KPa). The DIN standard commonly used in Europe corrects to a 68°F (20° C) day with 0% humidity and a barometric pressure of 29.92 in-Hg (101.3 KPa).
The resulting differences are as follows:
SAE J1349 is the most pessimistic and is currently used by US car manufacturers for their ratings.
DIN gives 3.2% higher numbers than SAE J1349.
SAE J607 (or STP) as commonly used on Westech and other engine dynos gives 4.0% higher numbers than SAE J1349.
So as you can see, the correction factors can be manipulated by unscrupulous dyno operators to produce over optimistic numbers. Likewise, a performance part manufacturer could inflate their claimed HP gains simply by applying a more generous correction factor on the dyno.
My numbers turned out to be 204rwhp@4500rpm and 250rwtq@3500-4000rpm using the STP correction. The 204rwhp isn't the true peak though because there was a glitch with my ECU that was causing the rev limiter to cut in at only 4550rpm and at that point, the HP curve was still rising.
I agree that ultimately the best place to test performance mods is on the dragstrip.