Smart questions
Smart answers
Smart people
Join Eng-Tips Forums
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Eng-Tips
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

jraef (Electrical) (OP)
20 Aug 07 20:24
I am a regular poster in other fora, and I know the rules about personal projects, but please indulge me for a bit before red flagging this thread.

I am getting a new company vehicle, a Dodge Charger with a 2.7L V6, the smallest engine option (corporate edict). I have this engine now in a Magnum, it's a dog and I am afraid of being rear-ended trying to get on to freeways. I know the Charger is a little lighter than the Magnum and that should help acceleration. But I want to see if these performance chips I see advertised all over really do change the timing and fuel mixture enough to make a difference, and if there are any pitfalls I want to avoid in using them.
MikeHalloran (Mechanical)
21 Aug 07 0:24
Take out all the weight you can, and replace the stock air filter (with a stock air filter) often.

It's someone else's car; do anything that voids the warranty, and any problem becomes your problem.

Aftermarket chips may become obsolete as ECUs get smarter ... which has an upside.  If you got one that's adaptive, it may respond to higher octane fuel with better performance.

Mike Halloran
Pembroke Pines, FL, USA

patprimmer (Publican)
21 Aug 07 0:55
Performance chips presume the factory engineers got it wrong or had a different set of priorities that reduces performance.

Usually, they have to compromise between performance, emissions and economy, but they are not far off re performance, and a change to improve performance generally results in an unnacceptable trade off and the only real value in aftermarket chips is to retune if other changes have been done to the engine.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.

TheBlacksmith (Mechanical)
21 Aug 07 7:47
Agree with above; not a lot left to be gained in power chips, but reduce the work to be done, take out weight, clean air filter, maybe synthetic oil, keep tires properly inflated or add 2-3 pounds without exceeding maximums on the sidewall.  I have an F150 with the 4.6, EPA rated 19 mpg highway, with K&N air filter, Mobil 1 and bed cover that is plenty fast enough to avoid merg problems and gets 18-19 in local rush hour traffic and 20-21 on trips, so reducing the work to be done works.
MacGyverS2000 (Electrical)
21 Aug 07 7:57
Heavily depends on the vehicle, too, IMO.  For example, Honda pulled an extra 10+ hp out of the S2000 engine in 2002 simply by leaning out the fuel map... the first two years were pretty pig rich, a reason why many of us went with piggyback computers.  It also allowed the lowering of the VTEC engagement point, which proved very useful on cars that were forced induction or changed cams.  Heavy duty engines can see larger gains, depending upon your driving style, and some of the better systems allow you to change programs with the press of a button.

Dan - Owner
http://www.Hi-TecDesigns.com

jraef (Electrical) (OP)
21 Aug 07 12:55
In researching this a bit, it appears as though these chips simply "fool" the ECU into thinking that the intake air temperature is higher, which makes it (the existing ECU) change the fuel mixture and timing. Most of the ones I see seem to be full of hype and want you to spend anywhere from $25 to $429! One however, sells for $6 and the guy has this bit of "honesty" posted on his website.

Quote:

Dont be fooled by those other guys claiming to get more then 30hp with this simple item... Its almost impossible to do.  The largest gain i have ever seen is a 28.6 hp gain.  The average gain is around 10-15hp but can range up to around 25hp. Not many cars get above 25hp with this mod, and if they do its not much higher.... Remember that car makers must limit power on engines due to legal regulations. This is one of those modifications that takes that legal barrier off and allows your engine to breathe and go faster than before.

... This PERFORMANCE MOD will modify your AIR/Fuel ratio and slightly change your engine timing to run stronger and with increased power. ...It connects to the car's intake systems IAT sensor. Once the mod is installed, the sensor will read a different air temperature then what is really coming in.  Once this gets relayed back to the ECU it will add more air and fuel to the car, giving it that extra horsepower and torque that you are looking for.

I find it difficult to believe it could be that simple. But then again, I had a Dodge shop tech just tell me that he tried one (of the $400 variety) to see and put it on their dyno. They observed that it did add about 15HP (stock rating on this engine is 190HP, they got 204-206HP). I'm also dubious that 15HP is going to make much of a difference in acceleration, but for $6, maybe it's worth a try eh?

What could go wrong with tweaking the temperature input though? Loss of fuel economy? Overheating the engine? Fouling the electronic ignition? I'm so far behind all the new engine controls I have no clue (I was shocked to discover there are no spark plugs any longer, or at least whatever is on the head no longer looks like a spark plug).
MacGyverS2000 (Electrical)
21 Aug 07 13:01
jr, the "chip" you're talking about is simply a resistor... as stated, it simply cuts down on the return signal from the air intake sensor, fooling the ECU into thinking the intake charge is cooler than it really is.  Yes, this will free up some power, at the expense of your safety margin for detonation.  Don't spend $6 + S/H, just look in your junk parts drawer and grab a few resistors out of it.

The "chips" I thought you were talking about are plug-in modules that actually reprogram the fuel/air maps on the stock ECU (usually around the $300-$400 mark).  These will show some impressive gains, depending upon your vehicle.

Dan - Owner
http://www.Hi-TecDesigns.com

MacGyverS2000 (Electrical)
21 Aug 07 13:03
Oh, I should also add... sparkplugs are still used, but what you're seeing are coil packs.  Instead of a single-unit distributor cap launching high-voltage spikes down a long wire, the coils are simply placing a miniature transformer on top of each plug (which also allows for pulse length shaping by the ECU, if supported).

Dan - Owner
http://www.Hi-TecDesigns.com

jraef (Electrical) (OP)
21 Aug 07 14:19
Excellent info, thanks. So the $300-400 chip modules are indeed different then. I thought it was a little cheeky to charge that much just to fool the ECU.

The $6 one is a "plug in module" as well, but he probably just knows the pin-outs for a connector and inserts the resistor. So if I understand you, there is a risk in doing this, but it may indeed provide a boost. Maybe I should buy one to get the correct pin-out and modify it to put a bypass relay around the resistor so that I could flip a switch only when I wanted the boost eh? Kinda like the Batmobile's afterburner button!

MacGyverS2000 (Electrical)
21 Aug 07 15:35
He may know the pin-out, he may not.  Typically they'll include a little pack that has a few wires going into and coming out of it.  Open it up and you'll find nothing but good ol' resistors.  If it's a generic piece, they'll just tell you to put it inline of the IAT line, but may never tell you what line that is on your vehicle.

The risk is there, but it's not very high.  If the signal value is dropped too much, the ECU is going to notice something is off and probably throw a code.  If your ECU has half a brain, it will also have ping sensors and cut back timing if you start to get detonation.  Not really worth putting in a bypass relay as the power boost is not great enough to be butt dyno noticeable by any but the best of butts... autocrossers and racers may notice the difference in power, but the average driver isn't going to have a clue.  Expect 5-10 hp, if you're lucky.

Dan - Owner
http://www.Hi-TecDesigns.com

jraef (Electrical) (OP)
21 Aug 07 18:41
Thanks for the time and attention. I'll probably forgo it then and just live with the doggy engine they allow me to buy. I can't imagine why they won't let me get the Hemi... oh wait, maybe it's because they pay for the gas!
MikeHalloran (Mechanical)
21 Aug 07 21:46
You could make the argument that the Hemi greatly boosts the resale value.  

It also doesn't necessarily consume more fuel than a smaller engine would, especially if you're buying the tires.

So far, I've owned six Camaros, with 2.8, 5.0, and 5.7l engines.  They all weighed about the same, and had similar aerodynamics.  Within the error of my measurements, they all got about the same mileage when driven over the same route among the same bunch of idiots.

Mike Halloran
Pembroke Pines, FL, USA

cibachrome (Automotive)
23 Aug 07 21:42
Hey Mike:
 You need to run the 5.7 with Displacement on Demand (Active Fuel Management)  You can run it on 4 cylinders just about all the time except when you punch it.  This can be done mechanically if you realize that the intake manifold is split between alt.cylinders.  

The correct answer to this is " Don't let the EPA catch you doing this".  When Smog stations are empowered to check you every year, the LAW already defines the penalty ($) fine.  The real reason the mileage is lower is because the converters need fuel to do their thing so some has to be passed onto it.  When you adjust the mixture, the nitrogen oxides climb and you are in violation of Federal Clean Air Act mandates.  Don't blame the manufacturer, blame an ignorant Congress.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!

Back To Forum

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close