Comments on (Temperature) Performance Chips

[jfrabat]

I found one of those "performance" chips on eBay that trick the car's computer into making it think the car is running cooler than it really is (ir is it hotter???) by conecting (in the case of my Jeep) to the Intake Air Temperature (IAT) or (in other applications) to the Mass Air Flow (MAF) sensors, and thus (from what they say) adjust the timing to achieve more power and torque.

Typically, I do not beleive in these chips, but this partiular one has a chart from a Dyno test (speed cube, http://cgi.ebay.com/ebaymotors/Jeep-...spagenameZWDVW), and it does show a significant improvemnt. Because I have a 4 banger, I am trying to squeeze all the power I got out of that engine so that I can run new 33" tires without having to regear (granted, I will loose 5th gear, but that's OK by me). According to these guys, in my application, the increase in power should be 4 to 5 HP, which woul be significant enough for me to go out and spend the $30 (with shipping) that the sensor would cost me...

Has anyone run one of these chips on their Jeep? Any comments about experiences with suh chips? I plan to take my car to Panama (Central America) in a few years when I move down there (there are A LOT of trails there!), and the temperature there is quite hot (90 average, with more than a few days of 100+); any idea what the effect of the chip would be in a hot environment?

I posted this question in the performance forum, but no one answered, so I do not know if it is beause nobody saw the post, or if its because nobody has experience with these chips... So to those that saw the previous post, I apologize.

 

[fast_Z28_guy]

not worth it...they are bogus and have been made for just about every car out there.

they trick the computer into thinking that the incoming air is cooler, which makes the computer add more fuel and more spark. and many times by doing this it will create knock in the upper rpm band. knock is picked up by the computer and it in turn pulls timing...called knock retard...which hurts performance.

if you want cooler air...make a cold air intake...

here is a technical article on it, it is on a V8 camaro but the idea is the same. and they use actual scanning software to monitor engine perameters.

 

[jfrabat]

Thanks, Fast.... That was jus the kind of answer I was looking for.

I guess the best way to increase power with the mods I have on the engine and those I plan to install (Throttle Body Spacer, removing the air restrictors, and soon to come, new 4.0L throttle body) would be to disconnect the O2 sensor (after all, they put it there to control emissions, not power!), keeping the ECM in Open Loop mode (like when the engine is heating up after start-up) and thus allowing the engine to operate without emissions data and thus reach its full potential. Of course, this would mean higher fuel consumption, so maybe I should only do it only when hitting the trails...

Felipe

 

[TWDJ]

Be careful with the "modifications" you make to your engine and emission controls. Anything that allows more fuel into the engine, intentional or not, puts more fuel into the exhaust and THAT negatively affects the catalytic converter. To pass the bi-annual SMOG test, I just replaced my cat as the O2 sensor had failed ... it was not a cheap procedure.

Seeing as my off-road time is low-speed, I've been somewhat reluctant to purchase performance enhancements for sake of performance only. Typically performance is only gained at the higher engine speeds that I never reach.

Of course when something breaks or wears out, that is another matter altogether ::grins::

 

[jfrabat]

TWDJ,

As you can see, my mods have mainly been to increase air flow, so that should not be a problem for the emision. As for the Cat, it was replaced by the dealer after I bought the Jeep, so it should be good for at least another couple of years (it is a crappy new cat, but it was free and it was new, so no complaints here ). The Cat-Back I changed because the muffler broke, so it was like driving a race-car to work everyday (and like you said, if something breaks, might as well install something good!).

In the engine bay, the only mods done as of now are the K&N filter, the Helix TB spacer, removal of the air restrictors in the air intake box (all the previous mods intended to increase air flow), a new Accell coil (the old one was acting up also), and a new O2 sensor; soon to be added will the 4.0L TB (again, to increase air flow).

The rest of the mods have nothing to do with the engine or performance (lights, hard top, etc.).

In any case, the increase in air flow should not have any effect in HP or torque because the O2 sensor will pick up any change in the exhaust oxygen levels (lean or rich mixture) and adjust the engine accordingly to reduce emissions to the programed levels. Of course, on the trail, I could unplug the O2 sensor and gain some additional power by having the ECM run a Closed Loop for the O2 sensor (like I mentioned above), but I am still not sure how much more power I would get... In any case, these mods should not affect the emmissions test in any severe way (at least not now with he new O2 sensor!).

Felipe

 

[TWDJ]

Improving air flow efficiency (in and out) is always good, I just never could see spending the money for 5% here and 10% there at 5400 RPM ... BUT! ... if it needed to be replaced that was WAY COOL!

My only thought was your comment about disconnecting your O2 sensor. When mine failed, it trashed my catalytic converter which needed to be replaced. After removing the old, cheap failed cat and replacing it with a better working cat WOW, what an improvement. Apparently the cat was plugged up and robbing power in a big way. After all exhaust was replaced (header pipe through tail pipe) what an increase in power.

I just did not want you to run into the same thing while modifying your rig.

 

[fast_Z28_guy]

ok...i'm new to jeeps...but not new to automotive performance. but who did you get the info on unplugging the O2 sensor from?

that sensor is not there only for emissions. it's there as a VITAL feedback sensor for the computer to adjust the long term and short term fuel trim...ie...a/f ratio.

now i realize (at least on camaros) when you go WOT (wide open throttle) the computer ignores the sensor input and uses a preadjusted set of perameters to dictate how much fuel and spark to give the engine, but when running anything under WOT the O2 sensor is a major piece of the system.

on my car...unplugging it would send the computer into "limp home mode" which is a severely detuned state. something along the lines of 20-30% drop in power.


techniques for building power in any engine are generally the same

easier air in
easier exhaust out
more fuel
less parasitic loss

you've got the easier air in side taken care of i think. although you can also go as far as working the air flow inside the engine. higher lift rocker arms open the valves more, ported heads and multi-angle valve jobs allow better a/f atomization and air flow into the cylinders, and then the obvious ...bigger camshaft

exhaust side is gonna be headers, high flow cat (or offroad pipe) and a good freeflowing exhaust

more fuel would be in the tuning or in a round-about way the camshaft. and also by getting colder air into the engine you allow for more fuel to be added which increases power. something like a good cold air intake system can do wonders. a good rule of thumb is for ever 10* drop in incoming air temp, you will see a 1% increase in engine performance. so changing from 100* air from the engine bay to nice cool 50* outside air could show 7-8hp.

less parasitic loss deals with the accessories on the engine. going to an electric fan is a huge help, as is an electric water pump.

 

[jfrabat]

OK, got it... Unplugging the O2 snser - BAD!

It is just that I read that on this older jeeps (before the TJ), the sensor only detected the amount of O2, and thus adjusted the mixture until you got EXACTLY the preprogramed amount. Because of this, any mods to the engine (as allowing more air to burn more fuel) would be neglected because the O2 sensor would automatically adjust the fuel mixture taking into consideration these new paramters, and would thus in turn neglect all the benefits from increasing air flow in the first place. But I am no mechanic, so I could very well be basing my analysis on erroneous data, so I'll take your word for this...

Felipe

 

[jfrabat]

By the way, Fast, I am planning on doing the Turus electric fan conversion, so that should help me regain a little more power (plus, it should help me keep cool). But I will need a larger alternator (I have the stock one, and I think it is only like 80A). Any reccommendations for this, anyone?

As for the water pump, I intend to replace the stock one with the FlowKooler pump, which not only significantly increases flow, but suppossedly requires less HP (32% less, to be exact) than the stock one. Any opinions on this pump? Experiences?

Felipe

 

[Utah_jeepster]

It sounds like your trying for all the power you can get out of the 2.5L.
We have several in our local club that are trying for the same thing here. First off without doing your gears your going to loose power, and off road tourqe. Even doing diff gears your going to loose that because the 2.5L doesnt push a lot of tourqe any way.

Of the three that have the lease of trouble on the rocks ,two have gone to Air-raid intake, you will see improvment here over just an K&N in the stock air box near 12hp. Some sort of exhaust with a cat back system and a flowmaster. Getting rid of the factory exhaust manifold along with an intake will give your 2.5l a shot in the rump.

All have gone to an electric fan set up. Two with aftermarket radiators. Watch yours after switching to a high flow water pump, it blew Tim's bottom right out of his stock rad. Factory radiators are a brass, plastic combination that just sucks. Make sure you also start carrying the drain pepcocks. I blew mine out once...I now carry three...darn high flow water pump.
You will not need a new alternator to run a electric fan.

Of the three rock crawlers only one didnt go as extream...he just went over board. Picture a 2.5L on 35's MT/rs that can beat some 4.0's getting on the freeway. Randy went to a Avenger Super charger with a 62mm throddle body in front of it. You could never tell all he had was a 2.5 inside.

 

[fast_Z28_guy]

sorry boss...but i can't really help you on specific brands, or companies of products to buy.
like i said...i'm new to jeeps.

i've got the knowledge for the theory of how things will work...just not what brands. i've been fixing and modifying camaro V8s for over a decade...and i do ALOT of research.

the ideas are the same...just the way they apply sometimes differ.


some thoughts..

you talk about "more air in"...when in actuality it's more like easier air in. shy of using a supercharger or turbo...you don't really increase the amount of air getting to your engine. you decrease the resistence to getting the air in.
you can think of the engine as a big air pump...draws air in...then pushes it out. the easier you can accomplish that the more efficient the motor will be...ie...more power.
you can be the best marathon runner on the planet, but if you can only inhale and exhale through a drinking straw...you ain't gonna do ****!

so the bigger air intake, free-er flowing air filter, wider throttle body....ALL help reduce the restriction in the intake system.
and on the other side, headers, bigger exhaust pipes, mandrel bent tubes and free flowing mufflers...all help reduce the resistence to the exhaust getting out of the engine.


as for something Utah said...i would steer clear of the flowmaster. they sound great but have been shown to be one of the more restrictive aftermarket mufflers out there. i've seen numerous guys gaining 8-10hp by installing a muffler bypass...called a cutout...on a flowmaster exhaust on various v8 camaro/firebirds.
now they are better than stock...and they sound great! but there are better choices out there.
my personal favorite is magnaflow. they are a typical "box" shape muffler like the flowmaster, but the internals are more like a glass-pack. with a perforated tube directly connecting the inlet to the outlet. the perforations allow for the sound to escape into the glass packed muffler body, but the muffler still flows nearly as well as a regular piece of exhaust pipe.

gains will be about as good as you can get, and the sound will still be great. they also sell them in stainless...if you have the coin.

if you wanna hear how they tamed my 450hp camaro down...here are vids. this is with a dual 3" exhaust, camera was not moved between films.

no mufflers...straight pipes
dual magnaflow mufflers

 

[redrooster]

Super Unleaded will probably give you as much performance as that crappy chip.