- First Name
- Jim
- Joined
- May 25, 2017
- Threads
- 45
- Messages
- 1,311
- Reaction score
- 1,299
- Location
- jackson nj
- Vehicle(s)
- 59 Bird, 70, 74, 78, 79 Broncos, 84 LTD 331 w/Vortech, 86 Capri 5.0 turbo, 14 Stang GT, 17 Fusion Sport
- Your Bronco Model
- Undecided
VERY hard to find dyno's down near idle, but this is what I've been able to dig up over the years.Show the dyno chart
No it can’t I’ve driven plenty
from 18 wheelers down
Stock 4BT
Stock 6.2 LS
mild modded 5.0 (not 1000, but 1200 and @ the wheels, so need to add approx 15%)
2.7 eco (chart I made from a well known eco tuner dyno, I found down to 1500, I guessed at 1200 RPM torque, just to compare to 5.0 dyno I had)
LS7 headers/cam
Anyway, even a 6.2 (not big block) beats 4Bt stock for stock (360 vs 198 @ 1000 RPM). Yes, 4Bt can take tons of boost and power stock, but that only makes turbo lag worse. My contention has always been I don't want the non-linearity of a turbo motor in extreme rock crawling situations.
The ECO's do a great job minimizing turbo lag, but when you are in a situation like that video I just posted of me on that snow covered rock face. I had unequal traction that pulls me about 45 degrees off straight up, right into fresh snow. Unbelievably, it doesn't roll (being my junk is roll happy due to being 6200 lbs, that is very tall due to mog axles). A split second (actually an eternity compared to guys much quicker thinking than me ), I decided to do something about it, dump reverse and try to back up the hill (which again, unbelievably worked).
Not only did I not want a non-linear powertrain, but I didn't want nannies in the way of shifting instantly between fwd/rev (or worse yet, some traction/stability control trying intervene). I suspect the small Ecoboost motor (and manual trans combo) has at least some to due with broncobusters ability to control throttle. Your climbing a longer rock face and as RPM goes from 1500 to 3500 (lets say), torque changes non-linearly, and DRASTICALLY, without any more throttle input.
But don't get me wrong, love 4Bt's, they are very cool. Unfortunately, since I HATE Chebby, I would still take a 7.0 LS, which is about half the weight of a 4Bt all day long. The 4Bt will rule all day long in mileage though, so I understand the swaps in the past, compared to a big gas motor.
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