Dyno Testing Bolt-ons On The 4.0
- Thread starter Jezza
- Start date
Thanks ! , great to see larger exhaust bumps the power . I did enjoy see the bonus hood up dyno . run . Looks like we could all get around 4 h.p. by pulling the hood .
Thanks again for doing this Jezza !
Another weekend treat! Retain the stock catalytic converter or was it non OEM? Just curious as you pointed out so many nuisances can have on the dyno forever and OEM at 250k may not flow so great.
When the header goes on will that down stream cat be retained, upgraded or “test” piped?
When the header goes on will that down stream cat be retained, upgraded or “test” piped?
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Very good video. I like seeing the gains. I also feel like it highlights how much money people spend for horsepower in parts of the power band we spend hardly any time in.
I rarely see any sustained time above 3500rpm so big gains in those rpm ranges don't really improve my daily performance. Getting to see what builds good power across the whole power band is nice and seeing those gains with a hot under-hood temperature where it's going to normally operate is much more real-world. Bravo @Jezza !!
I rarely see any sustained time above 3500rpm so big gains in those rpm ranges don't really improve my daily performance. Getting to see what builds good power across the whole power band is nice and seeing those gains with a hot under-hood temperature where it's going to normally operate is much more real-world. Bravo @Jezza !!
Yep, everything is still on it except for the throttle body spacer. The spacer was messing with the throttle valve cable and didn't have enough adjustment to get it back in spec.
It has the stock single cat. I might do a video later with the cat removed and strait-piped. I may also do an open header pull as well. Maybe someday if I have time. The header just bolts up to the stock pipe, so the cat will stay.
Thanks ! , great to see larger exhaust bumps the power . I did enjoy see the bonus hood up dyno . run . Looks like we could all get around 4 h.p. by pulling the hood .
I'll just drive with my hood up. It's about the same level of distraction as the average driver engages with today anyways.
Bottle of nitrous?
Edit: looks like it's been done already:
https://www.jeepstrokers.com/forum/viewtopic.php?t=2032
https://naxja.org/threads/nitrous-on-4-0-cherokee.89037/
https://www.cherokeeforum.com/f59/holy-just-ran-100-shot-nitrous-express-126283/index2/
Edit: looks like it's been done already:
https://www.jeepstrokers.com/forum/viewtopic.php?t=2032
https://naxja.org/threads/nitrous-on-4-0-cherokee.89037/
https://www.cherokeeforum.com/f59/holy-just-ran-100-shot-nitrous-express-126283/index2/
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Question... if a bolt-on causes it to loose power do I take it off???
I would remove it if it could affect the repeatability (or credibility) of results in subsequent tests.
For a lazy example, an oxygen sensor spacer probably has no power gain, but it can change how the engine chooses to self-tune. That could result in a future mod, perhaps a new intake, to perform more poorly than it might otherwise.
There's also the possibility of competing mods, where one is pretty much null with the other installed, even if both would show a gain in isolation. Fresh oxygen sensors probably help with power. Tuning the PCM to enter PE instantly also probably helps with power. But they don't work together, and the max benefit you'd see from both at the same time is exactly what you'd see from running PE alone.
Depends. Will it build MORE power with further mods or is it a total dud?
Pulled the engine tonight to install the cam and headgasket. It's a bit on the greasy side. I might have to hit it with the power washer as well.
Heck yeah,can't wait to see the cam swap results! I'd estimate a good 30 more Hp?
And it's only up once you get those 1.7 rockers on too!
Shadetree4.0
New Member
Well Damn! I have been following all of your work and really appreciate what you are doing. I was hoping you would do headers first before pulling the engine so I could see the results. I don't plan on tearing down the motor 
I still love what your doing though!
I still love what your doing though!
I think 30hp is overly optimistic. I think more like 15-20hp on the high side of a big cam which I doubt he's going to run without increasing compression and stock displacement. Realistically without knowing the cam specs, I guess 10'ish hp.
Well if it’s not headers next, shave that head! I had a CJ7 that blew a head gasket on the 2.5. Took in for mandatory crack/warp check, told the machine shop to go ahead shave that as aggressively as the felt was safe.
Compression increase shows everywhere on the curve, so the motor gained some pep but had zero detail on how much the old man took off.
Compression increase shows everywhere on the curve, so the motor gained some pep but had zero detail on how much the old man took off.
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