Performance Chip? *Newbie Question*

[udlose2]

I have seen plenty of items on Ebay for performance chips and also seen a lot of people say it is nothing more than .50c resistor from Radio Shack. Obviously the items on Ebay are people just trying to scam you into purchasing a .50c piece for $20 or more! Do this little trick work? Some responses say it does work but just get from Radio Shack. Does anyone have any info on this or how you would install the resistor? Thanks!

[Dalite]

I don't know the specific part values, or where exactly they are installed. What the resistor (or possibly diode) would do is modify the sensor reading on the sensor circuit that it is installed on. The computer would see the modified reading and adjust it's operation accordingly. The most common use I could think of would be to have the computer see a lower air temp that is actually available, and make adjustments that would provide a degree of performance that wouldn't normally be avaiable at the real outside temperature. I am sure there are other examples, and better explanations.

Overall, the result may be cheap improvements on apparent performance. In the long run, the changes may create other problems in the way other circuits are responding to the false info.

In most cases, the provider would encase the component in epoxy to hide the actual value of the part used. 1/4 watt 20% tolerance resistors used to be 2 for $.25 at Radio Shack. Switching diodes such as the 1N914 or 1N4148 could be purchased 10 for a dollar. Their cost is less than a pack of Juicy Fruit, but the knowledge of where to put them is what the selller is marketing.

Remember, you have no recourse with the seller if the low cost mod causes your servicing dealer to deny a waranty claim for repairs that they determine may have been caused by the sensor reporting inaccurate info and the PCM making adjustments according to that inaccurate info.

[2coolPT]

I originally posted this last July, here it is again. I'm not believing any performance chip hype, especially at $20 or even $400. In my humble opinion, you are waisting your money. The proof is in the test. Most people never test, they just think they have more power.
---------------------- reposted from July 2002 -------------------
My experience: I picked up a Jet Performance Module from Jet Performance Products (www.jetchip.com) at Automotive Engineering in Clearwater Florida, a reputable local speed shop. Unlike the ASE performance chip which requires sending in your e-prom assembly for reprogramming, the Jet Chip is an external module that runs in series to your factory chip. What attracted me to this unit was that you could turn it “on and off”, when the engine is not running of course; Otherwise you will blow an error code and unless you know how to clear it, you will have to take it to your dealer to clear it. (You won’t want to do this). While mentioning taking your PT into the dealer, I should mention that on the last page of the installation manul it states “If a problem occurs that may require you to take your vehicle to a dealership for service, first remove the Jet Performance Chip and reinstall vehicle back to stock.. This is not as easy is it may sound. I had installed quick disconnects and it was obvious that I had “messed with the system” which of course leaves you suspect as causing whatever problem you took it in for service for. Anyways, I had it installed and wanted to know for sure what the increase would be. Prior to installing it I was told that I could not expect more than a 12 -15 HP increase. I figured 150 HP stock plus 15 HP for 165 HP was worth pursuing. To check it out I contacted Tune Tech of Tarpon Spring, Florida. (727-939-8467) which has an “in ground” NHRA calibrated dynometer, The owner, Steve, tells me that he has de-bunked many a false performance enhancing claim for several local car clubs. Not that all are fake and worthless, just that some exaggerate the results you can expect. Some of the claims have been outrageous. We made seven runs total. First to establish a baseline without the Jet Chip, and then with it. The experience was disappointing from start to finish. After establishing the base run, and then installing the Jet Chip and turning it “on” it took four more runs to get a consistent reading. Erratic shifts to extreme lean fuel to extreme rich occurred three times. Finally back to back “successful (?) Runs. Steve runs a cautious operation and I had agreed that we would red line at 6,000 RPM. Optimum HP tops out at 5,000 RPM in whatever gear you are in. Anything over that and you are wasting gas and adding useless stress to your engine. Bottom line: I gained a whopping 1.4 documented HP !! My advice is buyer beware! According to Steve, Jet does make some good chips, but the external module for the PT is probably not one of them. The pictures below: are as follows:


Setup at Tune Tech

2coolpt on the dyno

Revving it up

Readout

Results

[MX-5]

Let me add to what 2cool said.

I wrote the install guie for the Jet module way back in winter 2000.

I'm an electronics and driveability specialist as well as an ASE master certified tech. I also write articles for automotive magazines.

I did extensive track and road testing of the JET after writing the install guide.
It does add significant power..... but only at part throttle.

The sensors it tricks are not read by the PCM above 85% throttle. So.. at wide open throttle, WOT, it isn't even working!
The same can be said for the simple resistor mods. They go across the temp sensors and they aren't used at WOT.

The PCM in the PT goes open loop and uses a preprogrammed fuel and ignition curve. It's programmed to go WAY rich to protect the drivetrain. Part throttle timing goes as high as 37 degrees advance. WOT will not go above 24 degrees total advance.
The PCM program add limitations that the aftermarket can't overcome.

I beleive the JET module has been discontinued. They certainly won't reply to me after I actually tested their junk.

I've worked with JET on other projects. Their modules and chips do work with PCM programs that aren't as limited as the PT.

Here's 2 base runs. Back to back showed a 3hp variance.
110hp and 113hp with an automatic trans.



This is the same DynoJet chassis dyno 2COOL used.

[Cal Cruzer]

That guy selling those on Ebay tries to sell them for about every car. From what I can gather is just modifies the signal from the intake air charge temp sensor. As stated above, at WOT the computer is reading from a lookup table, not using sensor input. Also, various mags have tested the concept of modifying this reading using various other means and it never really makes a difference. Like most other items, most people who buy it swear that it makes a difference, but it has never been proven by the dyno. I am always amazed that even though the company that MAKES the throttle body spacer admitted that it they saw no improvement on their dyno, people still buy it and swear they see a huge improvement. The "seat of the pants dyno" must be a lot more sensative once the wallet is made thinner.

[udlose2]

I saw that some truck magazine did a review on the throttle body spacer and said that there was a noticeable difference. Maybe the magazine has some sort of affiliation with the throttle body spacer people or was just simply paid off to give it a good review??!!

[Jerry]

OK. I've got to put in my 2 cents worth also. I have the Jet Performance Chip installed on my 2001 PT. I also have a JBA header, Magnaflow catback system, cold air induction and a sport air filtration system with NOS soon to come. To date the biggest performance boost that I got was from the Jet Chip. The Jet Chip was formulated to work with the automatic and one of the beauties of the chip is that it changes the shift points of the transmission. Now it shifts to low sooner and holds each gear longer. I won't dispute anyone on the horsepower gains but my 0 to 60 time changed the most with the installation of the chip. Believe it or not the chip was a better investment than the JBA header.

[MX-5]

Jerry,
Are you referring to the 5-wire little black box from JET?
The one that only ties into the MAP and throttle position sensors via 3 wires?

That one doesn't do anything with shift points. The auto trans will upshift at 5800rpm no matter what. The JET module I'm referring to does not do anything at wide open throttle. It does add some power at mid throttle, but the sensors are not read anytime you're over 85% thottle. Once you go 'open loop', only a reprogrammed PCM will make a difference.

[Ant]

quote:Originally posted by Jerry

OK. The Jet Chip was formulated to work with the automatic and one of the beauties of the chip is that it changes the shift points of the transmission. Now it shifts to low sooner and holds each gear longer. I won't dispute anyone on the horsepower gains but my 0 to 60 time changed the most with the installation of the chip. Believe it or not the chip was a better investment than the JBA header.

I don't see how it is possible for this specific "chip" to change the programmed funtion of the tranny.
What 0-60 times did you have before and after the install?

[TripleJackInGA]

The thing the guy (read: scam artist) sells on eBay is a resistor to alter the value on the AIT (Air Intake Tempurature) sensor. It makes the computer think the engine is cold, like when you firsty start it up in Winter, and as a result, dumps more fuel.
Not good for the long term, and would probably throw some codes , but it *might* give you a little go at the track.
Looks like a POS to me.