dyno'd the MJ last night....

J

JJacobs

NAXJA Forum User
Location
Fort Collins CO
90 4.0, AX-15, 3.07's, 31's. Got a massive 102/ 136 rwhp/tq. Shortly after that a built up MJ with a 4.6 and 38" TSL's took a turn and hit 86/ 138. Supposedly these are altitude corrected numbers, this is at 5000 feet. If I remember right the tq peaked at 3200 and the hp peak was 4400.

I just wanted to do a baseline before I start putting a cheap stroker together. Hopefully mine turns out better than the MJ on 38's did. :eek:

Can the tires really soak up that much power?
 
what gears was the built mj running? 38's and incorrect gearing will make for a bad dyno run. Those numbers seem horribly low. All of the dynos I've seen for strokers are in the 220+hp area.
 
I'd guess that those numbers are NOT altitude corrected - a stock 4.0 should show 140+ rear wheel horsepower.
I'd also guess the stroker is not running anywhere near its potential - either wrong injectors/fuel mixture/ etc as it should make 40 cu/in more horsepower as a minimum.
 
Ya hve to remember that is power that gets put to the ground. a 38 is a big heavy tire and that wieght has to be rotaded and acelerated so it takes a bunch of hp and tq to do that. just like turning a 31 with 3.07 compared to a stock 28in tire.
 
Big tires soak up HP like nothing else.

I'd be surprised if any of us 36-37" tire guys showed more than 150 Hp at the rear wheels with nicely tuned 4.6's.

CRASH
 
This is kind of funny- the owner of the built MJ, come to find out, has a reputation as a bit of a pathological liar. It's a stock motor. The weird part is that he's told several people who already knew the actual numbers, that he put down 167 HP. He's also known to sell parts that aren't his, and even tried to sell someone else's Jeep once. :rolleyes:
 
That number did seem horribly low for a stroker. I still smoke my buddies with stock motors and 31's with my stroker and 36's but 5.13's help. Sometimes I think I have too much gearing with the stroker, but I don't need to go over a hundred often.
 
What type of dyno was it? Mustang dynos read lower numbers than a Dynojet dyno.

My 4.6L stroker put down 160hp and 220lbtq at the wheels on a Mustang dyno. I have 32s and 4.10s and a 5 speed.

Here is a comparo from my built 4.0L motor with 32s and 3.55 gearing compared to my 4.6L stroker with the same 32s and 4.10 gears.

JeepCompare.JPG


AARON
 
CRASH said:
Big tires soak up HP like nothing else.

I'd be surprised if any of us 36-37" tire guys showed more than 150 Hp at the rear wheels with nicely tuned 4.6's.

CRASH
Click to expand...
your XJ is not on 36-37s :laugh3: does exagerating make you feel like a bigger man? trying to be like Richard (broken parts and all)? :laugh3:
 
BrettM said:
your XJ is not on 36-37s :laugh3: does exagerating make you feel like a bigger man? trying to be like Richard (broken parts and all)? :laugh3:
Click to expand...

That 6 should have been a 5, but may as well be a 3.

Big tires are a blessing and curse.

CRASH
 
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