Anybody know the Stock Horsepower of a '91 Wrangler YJ, with the 2.5L 4cyl? I wanna say it's around 120 but I could be wrong.

I think its more like 90

Hey YJ, did you ever find out the H.P. rating on your 91'? I just bought a 95 with the 4cyl. and I was wondering what it was rated at. Also, are there any easy bolt ons to add an extra 10-20 H.P.?

Easy bolt on's...Try a K&N air filter. It might not add 10-20 HP, but they supposedly guarantee a noticeable horsepower gain. You may also wanna look at a throttle body spacer. They help a little, keeps the airflow consistent instead of bouncing around inside your intake manifold.

best bolt on for the 2.5 would be a 4.0
but serriously, I would think a throttle body spacer would work wonders and be smog legal

the factory rating for a 2.5 is 120 h.p., the stock 4.0 makes around 180-190 h.p.

I speak from experience, the throttle body spacer does nothing for the 2.5 MPFI engine.

TB spacers work decent for throttle body injected engines because they allow for a longer air/fuel mixing zone. Since the 91+ 2.5L is multi-port injected the spacer doesn't do much.

The most you can reliably do for a 2.5 is bolt on a 4.0 throttle body (larger diameter), high flow intake, and high flow exhaust. I've read somewhere that Ford 5.0 injectors work well to provide more fuel to go with the increased airflow.

The factory rating for a Stock 2.5 AFTER '95 was 110-120, cause after '95 chrysler started putting the Neon 4cyl in the 2.5 Jeeps...before that, I did some research and I think it's anywhere from 90-110...still not a whole lot.

best bolt on for the 2.5 would be a 4.0I had a 2.5 in a cherokee, it was ok with a 4 speed and 31s but to put 33s or 35s .. nope. But every person i have met that tried to squeeze every last drop of blood/power out of a 2.5
was never happy in the end. For what it cost to do all the mods. just put a wrecking yard 4.0 in it and get it over with.
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I had a 2.5 in a cherokee, it was ok with a 4 speed and 31s but to put 33s or 35s .. nope. But every person i have met that tried to squeeze every last drop of blood/power out of a 2.5
was never happy in the end. For what it cost to do all the mods. just put a wrecking yard 4.0 in it and get it over with.
______
[_____]
(ollllllllo)
[]---o-[]

That's right. Save your money. I've tried it all...4.0 TB, TB spacer, bored out intake manifold, K&N, and snorkel. The only thing I ever did that I believe did help was (1) a good tune up and (2) a high flow exhaust. The problem with the exhaust (magnaflow) was that it was so loud I had to take it off after one week.