Topic: What next for a 2.5L?

[montanajeep]

I'm new, got that out of the way. no pics yet, I have a 94 Yj w/2.5, I have rebuilt the ax5, the 231 w/sye added.  lifted, runnig 33 12.5 procomp mudders.  I have installed a header, 2.5'' exhuast, a bored tbi/spacer, cold air intake, electric fan, 4.88 gears, locker in rear, I have yet to tear open the 4 banger, no oil use, good pressure.  Running out of ideas for performance on the original engine.  Like that fact that I can go all day on 15gal. of fuel.  Rock-it adjustable map sensor? Crank sensor?  Just can't see how that would benifiet me any.  Looked at supercharging it, I think I can do a v8 swap cheaper..(buddy owns a wrecking yard) however this forum has showed me (Cliffords)  has anyone purchased a cam, or roller rockers?  What gains?  
One more thing, do not buy an ax5 tranny form Jim Clark, I have nothing but trouble, 800.oo  gone..

[Jeffy]

I'd look into an ignition system.

[chrisfranklin]

Had a few minutes and was going through issues on ignition the other night.  I use an Accel coil and wires and, yes, Splitfire Platinum Plugs.  Have also use the Bosch Platinum 4 plugs in this engine with the same coil and wires.  Neither plugs has really made any difference

Anyway, I was under the impression that the Accel coil would allow you to gap plugs at .055-.060 up from approx .035 factory recommendation.   When I first set up this ignition system, I had gapped the  plug at around .055-.060 despite warnings on Splitfire plug packaging that "gap is set at factory" or something to that effect.  Engine was apparently misfiring at that gap and was generally sluggish even after serveral days to let the computer adjust;  I ended up going back to .035

However,  I recently spent 5 minutes and gapped the splitfire plat plugs to .045 upr from a confirmed .035, contrary to plug packaging advice;  engine definitely seemed sharper after that.  So gapping may be ok with Splitfire Plats, just don't over do it.

[chrisfranklin]

Also in a recent iginition info hunt, I learned that Platinum's value as a  spark plug coating is its tendency not to wear or otherwise cause the plug gap to increase (hence the 100k miles between plug changes with Platinum plugs).  Well, this was, at least, news to me.

But, Platinum is actually not great in terms of conductivity.  If the Splitfire Platinums perform ever so slightly better than other plugs that I have used, it ain't becuase of the platinum, but likely because of the smaller, sharper point off the electrode core that makes the spark jump a little easier.

Iridium is an even harder plug coating than Platinum that is now being used on consumer automotive applications. It has better wear characteristics thatn Platinum and allows a pinpoint-sized electrode which may also improve ignition efficincy a bit.  Been in use in industrial applications since the 60's, but formerly very expensive.

Maximum spark conductivity in plug appears to go to Nology Silverstone Plugs which use a silver electrode and core (silver apparently being the metal with the highest conductivity).  These plugs dont have any sharp electrodes or anything else, though.  And then you also have Nology's HotWire spark plugwires, famous for their high price, $150 bucks for 4, which apparently provide one with a modest performance gain from plug wires alone.      
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But, here's my real question:  Do any of you guys use an Accel Coil and if so, what gap do you run your regular or Platinum plugs at with this coil?  I am currently at .045 up from .035.  Was expecting to run .060!  :evil:

[Jeffy]

Well, it's been documented that Platinum plugs don't work that well with the Jeep engines.  Split-fires are a still a joke.  You'd be bettter off with standard plugs or if you want something fancy try Copper or even Iridium plugs.

I'm using LiveWires from Performance Distributors along with their Coil.  Since I was prototyping the kit for them, they sent me Autolite plugs which work fine at .060". But you can read the full review on the Product review forum.  If I was going to change my plugs, I might try NGK Iridiums but they're $$$.

[chrisfranklin]

I'm a sucker for the latest teched-up version of mundane autoparts.  But, $16 a plug for NGK Iridium plugs! Holy cow!  (Good thing its a 4 cyl and not a 12). And Nology Silverstones are $9 per.

Do you gap Iridium type plugs, you think?

[montanajeep]

Thanks guys, so.. your all saying run a new igintion system such as accel.  I gues its just money.......   I did put new plugs, plug wires, rotor cap.  basic tune-up when I first go the jeep less than a year ago. I have owned this jeep less than a year..  just work on it all the time. wheels good in the hills.  My only complain is power on the highway.

[Jeffy]

Personally, I really like the Perfromance Distributors setup.  It's a complete package and pretty cheap compared to many of the others.

I believe the whole thing is under $200.  You get nicer plug wires, billet aluminum clips, and I think a replacemnet distributor cap, rotor along with a hotter coil.  All in all, a decent setup that doesn't add any extra wires.  It allowed me to gap my plus at .060".  Stock is .035".  I had a Jacobs before and only gapped to .050".  Larger gap means that you'll have a larger spark and a more efficent burn.  That is as long as you can jump the gap.  Otherwise you'll see misfires which are really annoying.

In any case there is a full review in the other area.

[montanajeep]

wondering for the 200+ bills I will be spending, what kind of gains, if any will I get. I understand better burn, however will I even notice an increase in power? Like I said earlier, I have installed factory (new) plug wires, plugs, rotor, and cap..

[RedJeep]

Turbocharge it. check out this guy named joe. He has a do it your self manual, about to go visit him this weekend.

http://hometown.aol.com/turbochargedtj/myhomepage/auto.html

[yellowta]

Forget about the turbo stuff already. Will the ignition upgrade provide seat of the pants improvements or not?

[wildman4x4nut]

Yellow I can't say how much of a seat of the pants feeling you'll get. But I did notice a little better acceleration.

[Jeffy]

Seat of the pants is small but is noticable if you're sensitive.  :wink:  

Torque is up slightly.  Mileage might be a smig better. .5-1mpg. I did notice a big difference at higher RPM though. (>3000rpm)  The engine sounded a lot smoother.

[yellowta]

If power is better while cruising down the interstate, I'd imagine that it would improve highway mpg's.  I do a lot of running the roads so if it runs better at 70mph + then it might be worth it. Thanks