Topic: Abusing Squirrels

[grumpygy]

Its an Article in JP Magazine.

  They talk of how to get more power out of the 2.5

1. Let the engine breath.  Air intake system. 5HP
2.  4.0 Throttle Body 5-10HP
3.  Header Breath in Breath out. 5HP
4.  A High flow Cat and After Cat System. 5-10 HP
5.  Electric Fan. No increase listed
6.  Hotter Ignition 5-10 HP
7.  Gearing 5-10 HP
So far I've seen these on this site

8.  Roller rocker Kit with a 1.6:1 ratio  Stock is 1.5:1  Said to be good for 10HP.
9. Adjustable MAP Sensor Also good for 10HP.
10. 505 Performance turbo Kit good for 40HP.

So anybody else read that and what do you think

[95yjman]

the 2.5L is what it is, I don't think its ever really gonna be a power house. However I have no problem keeping up with everybody on the trail.  Mine only has a cold air intake, and I've got 4.88's now instead of the stock 4.10's.  My jeep does good for what it is.

[grumpygy]

  Well I did a little checking and they are nuts.  Roller rocker that they recommend if you can even find them run around $700.  The turbo Kits when you get it with all you need right at $3,000 and it is hard to find.

That adjustable MAP Sensor I could only find it as a Discontinued Item.  So that tells me it did not sell very well or broke easy.

[95yjman]

You might look into some of the build threads here, I know some guys here have done turbo's on their Jeeps heh

[sharpxmen]

Its an Article in JP Magazine.

  They talk of how to get more power out of the 2.5

1. Let the engine breath.  Air intake system. 5HP
2.  4.0 Throttle Body 5-10HP
3.  Header Breath in Breath out. 5HP
4.  A High flow Cat and After Cat System. 5-10 HP
5.  Electric Fan. No increase listed
6.  Hotter Ignition 5-10 HP
7.  Gearing 5-10 HP
So far I've seen these on this site

8.  Roller rocker Kit with a 1.6:1 ratio  Stock is 1.5:1  Said to be good for 10HP.
9. Adjustable MAP Sensor Also good for 10HP.
10. 505 Performance turbo Kit good for 40HP.

So anybody else read that and what do you think

first off that ads to about 70 HP (keeping the turbo out), not going to happen just with those changes that's a 60% increase in power, that means you need 60% more fuel flow (pretty much that's how you make more power with more air and fuel unless you eliminate losses).

stock roller rockers are 1.6 but old ones due to age they deform and deflect and the real deal is 1.5x where x is 0 to 3 with 3 the best case scenario (check my roller rockers project, i measured the valve travel). you can probably get 10HP out of 1.7 rockers (given that you do add more fuel). I just don't see those other 60HP coming out of nowhere just with air filter, t/b, ignition (no way that gives you 10HP, maybe if the one that was there was busted then yes, but that's more on the lines of getting back the stock ponies) and so on.

it's simply not possible without some internal mods and extra fuel to get 190 HP out of the 2.5, getting back lost HP it's a different story (for example you replace a clogged air filter with a high flow CAI - and boom, 10HP - well, 5 or 6 of those were actually there if you'd just replace the stock filter with a new one).

but things do add up and it will improve but not to that level (just to manage your expectations).

probably the most realistic one is the turbo, you can make more than 40HP so that i would say it's on the conservative side

[Dylan]

So gearing increases engine output by 5-10HP?  Funny, I always thought it just helped get the engine back into its correct power band.

[Jeffy]

So gearing increases engine output by 5-10HP?  Funny, I always thought it just helped get the engine back into its correct power band.

All magazines inflate their numbers to help support claims by the sponsors.  Who's going to want to buy performance parts if all they're getting is 1-3hp for every $100 spent.  Unless you spend big bucks for the forced induction people will realize it's not really worth it.

[sharpxmen]

So gearing increases engine output by 5-10HP?  Funny, I always thought it just helped get the engine back into its correct power band.

it probably will show an increase if they did not update the parameters with the new gearing ratio,produced horsepower will remain the same, just the logged output will be different (and erroneous of course).

[Dylan]

Hence why I don't bother buying or reading magazines anymore... I realize aftermarket modification companies like to inflate their numbers to help their product sell, but to imply that regearing somehow magically makes the power output of the engine increase is ludicrous.  It'd be the same as if I were to claim that removing 500 pounds of concrete that I had in the bed of my Jeep suddenly increased my engine output by 20HP; the engine itself is unchaged as is its output, it just doesn't have to work as hard.

Maybe I could use their logic and add a couple to the list:
Drive downhill --> 5-15HP (depends on steepness of hill)
Smaller diameter tires --> 5-10HP
Replace steel wheels with alloys --> 5HP
Shift transfer case into 4LO --> 50HP

 

[jramey]

I was reading that someone posted over on cherokeeforum, it was a home brew mod where a guy took aluminum sheet and cut it up to place it in between the exhaust and intake manifold to help reduce the heat on the intake from the exhaust. His calculations before and after the shield showed a 10 degree drop when using it. Seems like a very inexpensive way if you have aluminum sittn around to gain a few hp and slightly better mpg from the cooler intake.....im sure exhaust wrap would do bout the same too though

[Jeffy]

I was reading that someone posted over on cherokeeforum, it was a home brew mod where a guy took aluminum sheet and cut it up to place it in between the exhaust and intake manifold to help reduce the heat on the intake from the exhaust. His calculations before and after the shield showed a 10 degree drop when using it. Seems like a very inexpensive way if you have aluminum sittn around to gain a few hp and slightly better mpg from the cooler intake.....im sure exhaust wrap would do bout the same too though

You can buy reflective foil duct tape.  It's used to wrap up HVAC duct work.  I've used it on my air tube before.  It's cheap to buy and does work but it's not going to make miracles.  Makes a mess when it ages a bit and cracks then dust get inside it and collects.

[jfrabat]

The reality of the 2.5L is that it works just fine offroad, but it suffers at highway speeds.  You can improve HP, but typically, it is done by sacrificing low end torque (which is what you use when you wheel).  Now, I have a ton of mods on my engine with more coming down the road, and what I can tell you is this:

1. All the small mods help a bit here and a bit there, and many of them work better together than by each own
2. Gearing will not increase HP, but WILL increase performance (you'll FEEL more power).  I would say short of the turbo, it's the most felt mod, but it is also one of the more expensive ones.
3. If you want more power and do not want to use force induction, you can also try increasing the compression ratio.  10.1 to 10.5 seems to be a good range, but you will also need to run better fuel (91 octanes or more)
4. To have more power, like Sharp said, you need more air AND more fuel, and a way to ignite that mix; if you only increase one without the other, you will not get more power (the PCM will compensate as much as it can to be close to the 14.7 mixture, but it can only compensate so much).

Look online for what people have already done; there are a couple of turbo builds, I know Sharp was working on a supercharger (you ever finished that, Sharp?), and a someone increased compression ration not long ago.  Everyone here will let you know the good, the bad and the ugly of what they did, and you can choose which is the better option for you.

[JohnnyO]

first off that ads to about 70 HP (keeping the turbo out), not going to happen just with those changes that's a 60% increase in power

Even with the low end numbers that's 50 hp.  Ain't happening.  Probably the most you'll see short of a turbo/compression/cam mods is 15 hp.  To get more with those mods (in any 4-banger) will require spinning a higher rpm to see those bigger numbers, which isn't really the Jeep's ball of wax.
Ours holds speed on the highway a little better since I added an Airaid intake.  I might do a Banks header and exhaust and high output ignition, but that'll be about all.

[grumpygy]

Kind of wish they would have checked with folks who actually do work on 2.5's.  The guys who wrote the Article even said they felt the best way to improve a jeep was with a bigger engine.

[YJWralph]

I am happy with my 2.5 on the trails.  The squirrels just aren't gonna break axles and driveshafts, etc.  I have put a header and muffler on it, and use quality plugs, filters, etc.  Runs great and is reliable.   It is what it is on the highway, and I still love it...