Dyno Testing Bolt-ons On The 4.0
- Thread starter Jezza
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This is a top shelf effort ! Thank You ! The warm up , timed events , hood down , all point to the most realist , repeatable information that would demonstrate real world changes in performance. Great , very professional job , Jezza !
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I think an on-the-stall launch would equate to a better time and more power off the hit. I was trying to create a test that demonstrated the tip in low RPM power that some folks are terribly worried about. Discussions about power and dynos usually lead to someone complaining about the power only being at 4k plus. I may add another test in the next set that is a rolling idle tip in test. I want to measure some low RPM numbers as well.
Out of curiosity, does the 1997 TJ run in closed loop or open loop at WOT? I'm only familiar with the 05-06 for tuning.
Closed loop does allow the computer to compensate for changes in airflow and fuel flow, but open loop is basically just a guess. Closed loop should show changes pretty effectively.
Closed loop does allow the computer to compensate for changes in airflow and fuel flow, but open loop is basically just a guess. Closed loop should show changes pretty effectively.
I just realized my dyno data may be inaccurate due to overspeed.
I ran my stock 4.0 and then 4.6 Golen stroker with a stock ‘97 tune and the AX-15 in 4th (1:1). Both the stock motor and stroker peaked around 4400 RPM which was around 100mph with 33s and 4.11 gears. Numbers were 137hp stock/169hp stroker.
Edit: here’s the link:
I subsequently was unable to get my TJ over 100 mph (closed road, of course).
Not certain, but I think the stock 97 tune has a speed limiter? If so, another reason to get better tune or at least I’d like re-run in 3rd gear to see if numbers are different
I ran my stock 4.0 and then 4.6 Golen stroker with a stock ‘97 tune and the AX-15 in 4th (1:1). Both the stock motor and stroker peaked around 4400 RPM which was around 100mph with 33s and 4.11 gears. Numbers were 137hp stock/169hp stroker.
Edit: here’s the link:
Stroker Dyno Results are in… and they are not what I hoped for:
After 600 miles on the new engine, it had its first oil change and I headed back to the same Mustang Dyno the original 155K 4.0 was measured on in June when the motor made 136 hp and 168 ft.lbs. This calculated to represent a 24% drivetrain loss vs Jeep’s stock crankshaft numbers (181 hp and 222 ft.lbs). The now installed 4.6L stroker made 280 HP and 320 ft.lbs on a SuperFlow engine dyno in May. That was with no accessories, a holly stand-alone EFI system and an open header. I supposed Jeep may have used similar...
After 600 miles on the new engine, it had its first oil change and I headed back to the same Mustang Dyno the original 155K 4.0 was measured on in June when the motor made 136 hp and 168 ft.lbs. This calculated to represent a 24% drivetrain loss vs Jeep’s stock crankshaft numbers (181 hp and 222 ft.lbs). The now installed 4.6L stroker made 280 HP and 320 ft.lbs on a SuperFlow engine dyno in May. That was with no accessories, a holly stand-alone EFI system and an open header. I supposed Jeep may have used similar...
I subsequently was unable to get my TJ over 100 mph (closed road, of course).
Not certain, but I think the stock 97 tune has a speed limiter? If so, another reason to get better tune or at least I’d like re-run in 3rd gear to see if numbers are different
I would have to agree with this about seeing when does and engine make max HP & TQ.... Great to know but most of us never see more than 3K RPM's with that rare blip to 4K RPM's. So I can agree with what you're attempting to get at. And IMO would be where most members are going to be interested in if these mods added performance. Not knowing a lot about dynos I don't know how hard it would be to obtain these results.
Say what now? Speak for yourself, Mr. "Wild" man. Maybe "Mildman" would be more appropo
Say what now? Speak for yourself, Mr. "Wild" man. Maybe "Mildman" would be more appropo
I try to keep it off the rev limiter most of the time... And I did say most members... Not ALL members...
In my experience any throttle input over 75% or so forces open loop. I used the HP scanner software on the '97 and it was disabling the fuel trims at WOT. My '05 is the same way.
I just realized my dyno data may be inaccurate due to overspeed.
I ran my stock 4.0 and then 4.6 Golen stroker with a stock ‘97 tune and the AX-15 in 4th (1:1). Both the stock motor and stroker peaked around 4400 RPM which was around 100mph with 33s and 4.11 gears. Numbers were 137hp stock/169hp stroker.
Edit: here’s the link:
Stroker Dyno Results are in… and they are not what I hoped for:
After 600 miles on the new engine, it had its first oil change and I headed back to the same Mustang Dyno the original 155K 4.0 was measured on in June when the motor made 136 hp and 168 ft.lbs. This calculated to represent a 24% drivetrain loss vs Jeep’s stock crankshaft numbers (181 hp and 222 ft.lbs). The now installed 4.6L stroker made 280 HP and 320 ft.lbs on a SuperFlow engine dyno in May. That was with no accessories, a holly stand-alone EFI system and an open header. I supposed Jeep may have used similar...
I subsequently was unable to get my TJ over 100 mph (closed road, of course).
Not certain, but I think the stock 97 tune has a speed limiter? If so, another reason to get better tune or at least I’d like re-run in 3rd gear to see if numbers are different
I'm really not sure if there is a speed cut, I've never tried to get there. In my experience with lower power vehicles there is no reason to run 3rd on the dyno. You want the pull to last for a reasonable amount of time, but not all afternoon. According to DynoJet gear ratio makes very little difference with their system as the work is being measured by mass and acceleration. 1:1 is ideal, but doesn't work in all cases.
I did the runs on the tune up last night and the results were shocking, not at all what I expected. The stab test was not quite as informative as I had hoped. The torque converter flashed at 2k and only produced new data from 2k to 2.5k where all the other tests started.
I hit 5,000+ multiple times a day...
At one point I had a canned tune that raised the rev limiter to 6,000 without me noticing. One day, I completely forgot so was driving stick while accelerating out of a toll booth until I hit that 6,000 RPM rev limiter... Scared the crap out of me
At one point I had a canned tune that raised the rev limiter to 6,000 without me noticing. One day, I completely forgot so was driving stick while accelerating out of a toll booth until I hit that 6,000 RPM rev limiter... Scared the crap out of me
I bought the full tach, I use the full tach.
Was that high enough to start floating the valves?
I know my 2004 TJ Rubicon had the limit set at 92mph, which I've since bumped up to 99mph in HPTuners and could set to anything. I'd definitely bump it higher before any dyno runs. I believe the same adjustment is available in the 1997s. Not sure if you current tune is locked, but you could do a scan and a read to replicate it if necessary.Not certain, but I think the stock 97 tune has a speed limiter? If so, another reason to get better tune or at least I’d like re-run in 3rd gear to see if numbers are different
I don't actually want to go that fast in the TJ, but I hit that 92mph limiter a couple times over the years going downhill with just the right tailwind and the way it cuts power is unsettling to the jeep and it's occupants.
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