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-   -   2.5L power improvement (https://forums.off-road.com/jeep-short-wheelbase/1991-2-5l-power-improvement.html)

**DONOTDELETE** 10-30-1999 10:15 PM

2.5L power improvement
 
By putting in an electric fan, a new ignition system (Accel 300 ) and a K&N air filter will I see an increase in power? I know it will not be the 4.0L but if it would be noticable I will do it. All the parts I can get from Quadratec for about $500 and I can do it myself so that would also be the final cost. Is it worth it or should I not waste my time and money. I almost never go above 3000 RPM if that answers any questions so I am looking at the low range for power. Thanks for any input.


**DONOTDELETE** 10-31-1999 05:38 PM

Re: 2.5L power improvement
 
The K&N makes the biggest difference at high rpm (above 3000). I have never heard that the accel ignition system is worth it. A fan will help some but not much. Your best bet would be to go to www. turbocity.com (remove the space) and look under the Jeep power section. For the 500 you had mentioned you can get a lot more.

Nick Hagen
1995 Wrangler
33" Mud Tires and a four banger

**DONOTDELETE** 11-01-1999 09:23 AM

Re: 2.5L power improvement
 
I looked and saw the Power Kit Stages 1,2 and 3. Is this what you are talking about and do you use any of it? If so, did you see a noticable gain? Thanks.


**DONOTDELETE** 11-01-1999 09:33 AM

Re: 2.5L power improvement
 
yeah, the stage 1, 2, and 3 kits are what I was talking about. I haven't bought them yet because I have very little money (poor college kid). I've heard that they make a difference but can't personally confirm it. Short of a supercharger, it is had to get much of a performance gain out of a 4 banger. Of course, every little bit helps.

Nick Hagen
1995 Wrangler
33" Mud Tires and a four banger

GeeAea 11-01-1999 01:06 PM

Re: 2.5L power improvement
 
The one thing that you can all be assured of: if it has the CARB sticker on it ..........it is going to do virtually nothing for you. Borla's own dyno test show that their CAT back system ......doesn't produce any added power til over 5000rpm........does anyone frequent those light speeds? Oh....it'll sound nice.......and if you have an older motor (not your 4 banger) throwing on a 4.0 head with the injection and such (HEI etc.) will 'bring you up to speed" and show remarkable improvements over older hardware ..... but for the contempory crowd .......virtually anything that really adds any punch .......will increase the emissions .....hence it will not have the CARB sticker on it. This is why I feel that most of the stuff we see for "engine enhancements" fattens the wallets of the vendors more than it broadens our power bands. You'll note that although the TC site mentions x-xx hp gains......it doesn't show WHERE that power kicks in.......more than likely its in a rpm range that you'll rarely see. I bought the TC rock-it tube to reclaim the air box space.....that's it. If it makes commuting 70+ miles a day a little more economical [img]/wwwthreads_images/icons/laugh.gif[/img].(ya....ya..buy a geo metro)[img]/wwwthreads_images/icons/laugh.gif[/img].....so be it.

Throw a set of 4.88's in....then you may actually attain the rpm ranges where these products provide their added juice....that should give you all the pull you need and you're still under 3000rpms at 70mph with a set of 33" tires.
GeeAea


**DONOTDELETE** 11-01-1999 09:17 PM

Re: 2.5L power improvement
 
I have a 93YJ 2.5L and have noticed fairly noticable power increases in the 2000-3000rpm range by making the following modifications. Instead of the Turbocity rocket tube, I bought Rusty's Off-Roads version--a lot cheaper (www.rustysoffroad.com). Order the larger K&N to go with it. This gives your engine more air than it could ever hope to use. I also got the TFX cat-back system from Quadratec (great service from them!). This system is very solid (the muffler is as thick as most skid plates!) and sounds great, but is not obnoxious. These two items provided a true increase in usable power and for a total cost of about $220 are a bargain if you ask me. Because of the extra power (or me just pushing it harder) my jeep was starting to run a bit hot, especially on inclines, so I looked into Turbocity's ported thermostat housing--no luck, it is only made for the 4.0. I did by the high flow 160 deg. thermostat and took a Dremel to the housing to improve flow through it. It is fairly obvious where it is restricted, but be careful of the thinner areas of the housing walls. Now, even off road my temp gauge is pegged at 160 degrees. Good luck!


**DONOTDELETE** 11-02-1999 01:00 PM

Re: 2.5L power improvement
 
Thanks for all the information. It doesn't sound like there is a clear-cut piece of equipment that is going to make any real difference. I will just look for a 4.0L roll-over that is trashed but has good engine, tranny and transfer case to switch out. Thanks again.


GeeAea 11-02-1999 01:58 PM

Re: 2.5L power improvement
 
Nahhhhhh ......stay with the 4 banger........be a rebel! Slap in a set of 4.88's and crawl with the best of them....anyone can put a 6 or an 8 under the hood ......and presto chango......instant hp! ........but get there in a 4 banger.....and you've accomplished something. So what if you can't piss upwind in a class 5 hurricane when it comes the hp contest?
Let me correct myself .......the Paxton blower......carries the CARB cert. on it. It will give you an honest 40-50% power boost. At about $2-3000..it's a costly alternative to virtually any other powerplant option.

GeeAea
BTW-where do you live...it you're in a more "liberal" (darn.....now Dave is going to get started again .....I said the "L" word[img]/wwwthreads_images/icons/smile.gif[/img]) emissions state ..there are alternatives.....your profile is empty.


**DONOTDELETE** 11-02-1999 11:23 PM

Re: 2.5L power improvement
 
are 4.88s available yet?

also, for the catback exhaust- Gibson, TFX, or Borla? Should I get the headers too?


**DONOTDELETE** 11-03-1999 12:28 AM

Re: 2.5L power improvement
 
4.88's are not available for the dana 35 yet. They have been advertisig for a while but they are not available. Weak pinion gear anyway.




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