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-   -   '89 YJ power (http://www.wranglerforum.com/f218/89-yj-power-8626.html)

jlp 06-09-2007 06:36 PM

'89 YJ power
 
I bought an '89 YJ and put a Weber Carb. on it. It runs much better than stock but am wondering what else I need to do to this in-line 4.2 six to get more power out of it. I went the V-8 route about 25 years ago on a '47 CJ2A from an in-line 4 banger and am determined to get enough power out of this six. I can't believe that this engine was rated at 112 HP. The new in-line sixes (4.0) fuel injected are rated at 190 HP. There must be other ways to get this kind of power out of this six. I know headers will help and that is my next step. How about tubos or supers. Is there anyone out there that has experimented with this 4.2? At 258 cu. in a 200 HP+ target would be OK with me. Any suggestions? JLP

Grandpa Jeeper 06-10-2007 11:24 AM

Quote:

Originally Posted by jlp (Post 90129)
I bought an '89 YJ and put a Weber Carb. on it. It runs much better than stock but am wondering what else I need to do to this in-line 4.2 six to get more power out of it. I went the V-8 route about 25 years ago on a '47 CJ2A from an in-line 4 banger and am determined to get enough power out of this six. I can't believe that this engine was rated at 112 HP. The new in-line sixes (4.0) fuel injected are rated at 190 HP. There must be other ways to get this kind of power out of this six. I know headers will help and that is my next step. How about tubos or supers. Is there anyone out there that has experimented with this 4.2? At 258 cu. in a 200 HP+ target would be OK with me. Any suggestions? JLP

The first thing I did was upgrade to a 30,00 volt distributor. The fatter spark really gave mine a boost.

daddyjeep 06-11-2007 07:13 AM

The most noticable mod I made to mine was a complete exhaust. Pacesetter Header, catco high flow catylatic converter, and a Flowmastwer 40 series. This made a huge difference. I think the best way to get more juice out of a 4.2 is to put a 4.0 head on it so you want to look at this before ordering your header. The 4.0 head will increase your compression. Do a little research on this and see what you think, it has been a while since I looked into this and I can't remember all the details. I know you will want to get as much of the wiring as you can along with the,computer, intake, and fuel injection.


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