THE FREE MODS THREAD....feel free to contribute and I will up date.

submit you free mods list for the 93-97 lt1 f body cars. Open to debates but base your arguments on facts, I will update things as we go along.


FREE MOD LIST:
1 Throttlebody coolant bypass
2 Smog pump delete
3 EGR delete, must be tuned for.
4 Silencer intake delete
5 IAT mod. 4.7 ohm resistor in place of the iat sensor.( do not do this mod if its a 93)
6 Resistor inline of the knock sensor (93 only)
7 Gutt cat
8 Weight reduction: ?
9 Remove/bypass AC
10 tuning if you can do it

also of interest, lt1 overhaul
http://www.gmhightechperformance.com...ild/index.html

STOCKTA Registered User Join Date: Aug 2002 Location: Steubenville,Ohio,United States Posts: 240	I was haveing constant problems with false knock so I put the 3.9k resistor in place of the knock sensor. I made sure it was false knock by using 110 octane and scanning the car with a LT4 knock module in place and the computer was still pulling 9 to 12 *. Once I put that resistor in place the scanner showed 0* being pulled and the car ran so much stronger, It would just pull smooth on a 40mph rollon now it has no traction stabbing the throttle at 40 in secondhttp://www.camaroz28.com/forums/imag...es/biggrin.gif . I have put over 15000 miles on the car since I eliminated the knock sensor, plus i didnt need the LT4 knock module anymore so I gave it to my dad for his 96z. Later, josh __________________ 94TA 3014lbs 21* trickflows, converted vic jr., 780 cfm wet flow pro-system carb, SBC MSD IGNITION, built6spd, fuelcell, 250gph BG, the no everything mod http://www.camaroz28.com/forums/imag...lies/smile.gif hoping for 2900lb's this summer
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shoebox Registered User http://www.camaroz28.com/forums/avat...ine=1032989706 Join Date: Dec 1969 Location: Little Rock, AR Posts: 25,531	Re: Knock Sensor Mod Quote: Originally Posted by WhtLT1 Anyone have the resistor values that are needed for an OBDII car? Are they even different? How would I find them? OBD-I knock sensor resistance range is 3300-4500 ohms. OBD-II knock sensor resistance range is 93K to 107K ohms. __________________ Rob B 95Z A4 Tech Page (Part numbers / locations, How to's, Schematics, Diagnostic Trouble Codes...) Home Page - shbox.com
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Timberwolf Registered User http://www.camaroz28.com/forums/avat...ine=1295477484 Join Date: Oct 1999 Location: Battle Creek, MI Posts: 3,558 http://www.camaroz28.com/forums/images/misc/im_icq.gif http://www.camaroz28.com/forums/images/misc/im_aim.gif

http://www.camaroz28.com/forums/images/icons/icon1.gif go to Radio Shack and pick up a 1 watt 3.9k resistor. Unplug the connection to the knock sensor and hook the resistor up to the plug on the end of the wire, then wire it to ground. This will make the computer think there is NEVER a knock, so beware...if you get a bad batch of gas or something.... You can't just wrap it up and tape it out of the way unless you run something to ground the body to the block or frame. There is only one wire that goes to the knock sensor. It gets its ground from contact with the block itself. __________________ 2003 Harley Davidson Low Rider 2008 Jeep Wrangler

What are the LT1 free mods and how are they done? LT1 Free Mods by member Mean Green De-screening the MAF sensor. ****WARNING!!!?.THE MAF IS EXTREMELY SENSITIVE BE CAREFUL WHEN HANDLING IT! NEVER TOUCH THE WIRES EITHER! ***** Start by removing the MAF from the car and finding a clean area to work. There?s many ways to remove the screen, but probably the safest way is to use a Torx head socket and unbolt the 2 metal halves from the actual sensor. This will prevent you from accidentally damaging the wires. Set the sensor aside where it won?t get damaged. Some people have had some negative effects from removing the MAF screen, so I would suggest trying not to damage it while removing it. There is a small snap ring that can be removed with a pick or small screwdriver, and the screen will come out, in one piece. I?d do this just incase you need to reinstall it. If you don?t care about the screen. Grab a screwdriver and go wild. Throttle body bypass. Start by removing the intake elbow so you can easily see the underside of the throttle body. Locate the hose that leads from the radiator to the drivers side of the TB. Have plenty of rags ready and loosen the clamp. Some coolant will drain out, it?s not much, but try to keep it from spilling on the Opti. Next, find the hose that leads from the TB to the steam pipe. (it?s the other hose on the bottom of the TB). Remove the hose from the TB and from the steam pipe. Now take the first hose and connect it directly to the steam pipe. Clamp it down and you?re finished. Some people use caps to cover the ports on the TB, but it?s not necessary. Intake silencer delete This one requires a bit of creativity, but it?s pretty straight forward. Start by removing the intake elbow. You?re probably going to need to cut the clamp off the silencer, then remove it. Now you just need to find something to plug the whole with. I?ve heard some shampoo bottle caps and deodorant caps work or you can trace the shape on to some wood or aluminum and cut it out. Then simply insert the cap into the hole and use a new hose clamp to clamp it down. When inserting the cap, try to position it so it is flush with the surface on the inside of the elbow. 50 Cent Skip shift eliminator. Another one that?s not pretty but it will work. Go to Radio Shack and buy a 2200 Ohm ? Watt resistor. Disconnect the wire harness on the CAGS solenoid and insert one end of the resistor into each of the 2 ports on the harness (wire side, not the solenoid side) tape up the harness and resistor so water can?t get to it. Then tape up the solenoid connector for the same reason. Ziptie the wire harness somewhere out of the way so it doesn?t fall out and drag on the ground. This will disable the Skip shift solenoid, however the light on the dash will still light up when it?s trying to activate. Gutting the catalytic converter DISCLAIMER: FOR OFFROAD USE ONLY This isn?t technically free, but it?s usually cheap. WARNING?.you will fail visual inspection duringemissions testing and most people fail the smog test without a cat. The easiest thing to do is find a muffler shop and ask if they will cut out the CAT and weld in a straight pipe. It is illegal for them to do this, but most places don?t really care. Try to avoid the chain muffler shops, use an independently owned shop. They?re more likely to say yes. It cost me $20 to have my first one done. On my second car, I bought the owner lunch ($4.00 at Taco Bell) and he did it for me.

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I think you have covered em all...

Does anyone/everyone do the IAT mod? Any particular reason?

would the heater hose mod count? It doesn't add any power or performance really, but it can improve the looks of the car. It doesn't cost anything if you have some sort of hose laying around that fits around the spring. I used the hose from the AIR pump delete.

posting to keep track..

Quote:

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Originally Posted by hammz28

Does anyone/everyone do the IAT mod? Any particular reason?

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http://qcwo.com/technicaldomain/iat-...-vs-real-chips

IAT Resistor Mods vs Performance Modules vs Real Chips


Posted by Richard
Did you like this article? Be the 1st to spread the word in your group!


http://chart.apis.google.com/chart?c...-vs-real-chips
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IAT Resistor/Modules Vs. Performance Chips

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http://qcwo.com/technicaldomain/wp-c...8/11/eprom.jpghttp://qcwo.com/technicaldomain/wp-c...08/11/mod1.jpghttp://qcwo.com/technicaldomain/wp-c...08/11/mod2.jpghttp://qcwo.com/technicaldomain/wp-c...08/11/mod4.jpg

http://qcwo.com/technicaldomain/wp-c...08/11/mod5.jpghttp://qcwo.com/technicaldomain/wp-c...08/11/mod3.jpg

What are those infamous IAT resistor mods and performance modules and how do they compare with real EPROM racing or performance chips? Need a guide to try it out by your self? Find out here…What are performance chips (Real EPROM or ROM Chips)?Some facts:Chips = Memory Chips = EPROM or ROM (Erasable/Programmable Read-Only Memory)
ECU = Car Computer (Engine Control Unit)Just like your PC, car computers or ECUs have a CPU (Microprocessor or Microcontroller), RAM memory and a boot device. In their case, EPROM chips serves as the boot device, instead of a hard disk. These EPROM chips contain the ecu’s operating system and operating parameters data, and hold it even if the power is removed from the ecu for any amount of time, even years, due its internal architecture.http://qcwo.com/technicaldomain/wp-c.../eprom-big.jpg<– Real EPROM ChipThese EPROM chips were used on Non-OBD (1988-1991) and OBD-I (1992-1995) cars. In the case of the newer OBD-II cars (1996 and later), manufacturers use a different approach, being either an EEPROM (also called E2PROM) or (more commonly) FLASH ROMs. Both methods are very similar to an EPROM device type, but with newer features, like on board re-programming for example. All types of these ROM, EPROM, EEPROM and Flash memory chips, or simply “chips”, are called memory chips and so we will call them in the rest of this article.Once you put your car key to “ignition” or “on” position, it powers up the ECU, among some other circuits, and right after it is powered up, it immediately boots from the memory chip and reads the operating system from it, which is the program that will run and control the ecu itself and the engine. It does things like reacting or responding to the various sensor readings. The ECU will also read from the same memory chip, the parameters data, which is the data that will tell the ecu how much fuel to inject, how much ignition timing to apply, what to do if the engine is hot or cold, etc.What changes these real chips do:When an aftermarket memory chip is installed in your car’s ECU, you are changing the program or operating system running it. It could be either slight changes or a major reprogramming, depending on the intended purpose and the chiptuning Company. The new parameters programmed on that new memory chip will hopefully affect the behavior of the ecu and its response to the different signals received from the various engine sensors in a positive way, aimed in the direction of more power, or to accommodate new engine hardware like a Turbo system, aftermarket camshaft, or any other modification that require an ECU reprogramming. The result will be a change in performance that will depend on the program written in the chip.Some of the changes done to these aftermarket memory chips are (1) disabling the vehicle speed limiter or governor, allowing the vehicle to reach its maximum natural speed, (2) the RPM limiter or revlimiter is slightly raised, allowing higher engine speeds for an extra punch when shifting and (3) the fuel and ignition tables (maps) are are changed or “remapped” for optimum fuel delivery and ignition firing.

http://qcwo.com/technicaldomain/wp-c...11/image-1.jpg

What about the IAT resistor kit, IAT mod, etc?Facts:IAT Sensor = “Intake Air Temperature” sensor
AFR = Air/Fuel ratio, ideally it would be 14.7 units of air to 1 unit of fuel or 14.7:1 (lambda 1)The IAT sensor is a passive or discrete electronic component that will simply vary its resistance depending on changes in temperature (also called a thermistor). It has a negative coefficient, meaning that the higher the temperature is, the lower the resistance it will offer to the current flow and vice versa.

Different IAT sensors (external to the MAF):

http://qcwo.com/technicaldomain/wp-c...08/11/iat1.jpghttp://qcwo.com/technicaldomain/wp-c...at-sensor2.jpg

When a voltage is applied through a resistive network (shown below) of which the IAT sensor is part of, the output voltage from that network (”To ECU” in the drawing) will vary or “swing” according to the temperature of the air passing through the IAT sensor. This swing is caused by the mentioned variation of resistance of the IAT sensor, that at the same time causes variation in voltage drop. The voltage fluctuation at the output of the resistive network will be interpreted by the ECU as a direct reading of incoming air temperature variation.http://qcwo.com/technicaldomain/wp-c...008/11/ckt.gif
So why the ecu needs to know the incoming air temperature?The answer is a simple fact of physics. Cold air is denser than hot air, having higher mass by volume, meaning more oxygen content. The importance of this, is to allow the ecu to modify the Air/Fuel Ratio (AFR) to acceptable levels, so combustion inside the engine can be kept at optimum levels, allowing optimum engine power, preventing engine from knocking and having lower nitrous oxides (NOx) emissions. It helps to the understanding of this, knowing that a mixture of air and fuel (gasoline in this case) will only be highly flammable at certain proportions. Too much air, too explosive. Too much fuel, will burn too slow or won’t ignite at all. The engine will theoretically need around 14.7 grams of air to every gram of gasoline.The modification:Few ECUs will use the signal from the IAT sensor alone, to modify the ignition and / or injection to slightly compensate for the incoming air temperature variations. So making the computer “think” the incoming air is cold will make it do small adjustments to ignition timing and / or fuel injection and there is where the IAT Mod ideal originally came from.

It is accomplished by putting a fixed resistive value (fixed resistor) instead of the regular IAT sensor, simulating a cold intake air situation. Going back to the facts above, “the higher the temperature, the lower the resistance”, to benefit form this modification, we would need to make the resistor value high enough to make the computer “think” that the temperature is low enough. That would hopefully induce the ecu to inject more fuel and advance ignition timing accordingly, in an attempt to compensate the supposed incoming cold air.

http://qcwo.com/technicaldomain/wp-c...at-plugged.jpg

The problem with the IAT modification:Even more and more people that have bought those IAT mods are claiming that it does nothing. It is probably attributed to the fact that not all cars depend only on the IAT sensors alone to make the necessary changes. So, it is very probable that modifying the IAT sensor of your car will do nothing, or at least nothing noticeable.If you successfully modify the IAT sensor and the engine makes some noticeable changes, remember that the air will not be truly colder or denser, so no extra oxygen will really be present, ending up in a richer mixture, higher emissions and very probably lower performance, unless your car is already running way too lean because any previous modification or any existing engine problem and a richer mixture will benefit its performance.If you live in a cold area, you will notice no difference as the original IAT sensor installed in your car will already be in a better resistance value than the one you would insert. If you live in a hot area (tropic, desert), it will be worse than the ones in a cold area, as even less oxygen will be available for the combustion. If you live in a high altitude area, you will have similar or worse luck that the ones in the hot areas as oxygen and pressure progressively decrease with altitude, even if it’s cold.Regardless of the all mentioned above, if you finally make the car computer do a positive modification by installing that 10 cents resistor, remember that changes will be on the factory program range limits or specifications anyway, as the chip or computer program is still the factory installed one. All changes made by sensor modifying (any sensor), will stay in the factory specs since sensors can be read but can not bypass or override functions in the ECU, unless a memory chip with a modified program (performance chip) is installed.

Resistor:

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Don’t take my word!!!Please, don’t just take my word about this. You can experiment it yourself if you are a little skeptic about this or just want to try it (I would do). http://qcwo.com/technicaldomain/wp-i...icon_smile.gifDo it your self:All IAT sensors resistance, average from about 4700 to 5000 ohms (4.7K-5K) when the air temperature is cold enough to make an adjustment on ignition timing and / or fuel injection. The trick is to replace the IAT sensor by a resistor with a “cold temperature” equivalent resistance value, similar to those mentioned above.NOTE: For easy calculating the resistor you need, just use the online resistor color code calculator: Resistor Color Code CalculatorAll IAT sensors have two wires, but though many of them are installed alone in the incoming air path elsewhere after the air filter, some of them are incorporated inside the MAF (Mass Air Flow) sensor assembly. In that case, the MAF sensor connector will have 4 or 5 wires, where 2 of them will be connected to an internal IAT sensor. You will either need to find the stand alone IAT sensor in the incoming air path or identify the wires connecting to it on the MAF sensor connector if it is internal.In the first case, the installation is done by disconnecting the plug to the IAT sensor and inserting the resistor leads, making contact with the IAT sensor plug connections (the part that goes to the ECU and NOT the part that goes to the sensor).

http://qcwo.com/technicaldomain/wp-c...11/iat-mod.gif

In the internal IAT sensor case, you will need to cut the two wires that connects to the internal IAT sensor to some length, to attach the resistor. Using the picture bellow as reference, if for example the IAT sensor is connected to wires 1 and 3, you should cut where the two green crosses (”X”s) are in the picture and attach, either by soldering or by using wire nuts, the fixed value resistor you chose for your car at the pair of wires that go to the “ECU” direction. You must cover the other remaining two cut wires with electrical tape or better, with a terminator connection for protection. Please note that the below example is just that, an example. Wires connecting to the internal IAT sensor can be any on every different MAF type.

http://qcwo.com/technicaldomain/wp-c...ternal-iat.gif

You will be able to easily locate the internal IAT sensor by looking at the picture below. This will help in (1) knowing where to spray with the component cooler can when measuring for best value and (2) you can determine what wires are connected to it by using an ohmmeter, measuring between the IAT sensor leads and the connector wires.

http://qcwo.com/technicaldomain/wp-c...008/11/maf.gif

Remember, you will electrically replace, but not physically replace the IAT sensor. That is, you will connect the resistor to the cables going to the ecu, but will leave the sensor in its place. The resistor, the same as the IAT sensor, has no polarity. That means that you can connect either wire with either resistor lead.Now, since the resistor has a fixed value and the IAT sensor is out of the circuit, resistance will no longer vary with temperature. The car computer will permanently think that incoming air is very cold as long as the modification is in place.After connecting the resistor, just make sure it is covered with tape or any other insulator and you can leave it hanging in a safe area on the engine bay as long as it doesn’t receive too much heat.Now just do a test drive. How was it? Anything? No? No problem, you are not the only one. http://qcwo.com/technicaldomain/wp-i...s/icon_sad.gifExtra info:As mentioned before, the resistance values of the IAT sensor averages between 4.7k – 5k, but if you want to try the exact optimum value for your car, just take out the IAT sensor, if it is the stand alone version of course, and put it in an ice bath prepared in glass or cup. Leave it submerged for 1 or 2 minutes and measure the resistance across the two connecting wires or terminal with an ohmmeter, preferable a digital one, in the 20K or equivalent range.The measured resistance will be the optimal for your car. Probably you won’t find an exact commercial value that matches the measurement, but you can get the closest one. For example, if it measures 4633 ohms, then a 4700 ohm (4.7k) is a very common commercial value and will do the job just fine. Color rings for a 4.7K resistor will be Yellow – Purple – Red with either a Gold or Silver fourth ring. Check on Google for other resistor values color code if need any other value; Key word = “Resistor Color Code”.If your IAT sensor is the MAF type (5 wires) you can not submerge it as it will be damaged, but you may find a component cooler spray sold for electronic circuits thermal troubleshooting and spray it directly over the IAT sensor inside the MAF assembly and then measuring it with the ohmmeter before it warms back up. The only thing is that such spray will go lower in temperature than a simple ice bath.

http://qcwo.com/technicaldomain/wp-c...11/image-3.jpg

Make sure that the MAF sensor is completely dry before installing it back, since cold spraying it will make some condensation moisture.Now do the test drive.I know, probably it was the same or worse. That is the result of 90% of the cases. The remaining percentage? Well, an 8% is placebo effect and the other 2% maybe people that succeed in putting fourth of an extra horsepower (1/4 hp) and are content with that.What about those mysterious boxes called performance modules?

http://qcwo.com/technicaldomain/wp-c.../11/mod1-1.jpghttp://qcwo.com/technicaldomain/wp-c.../11/mod2-1.jpghttp://qcwo.com/technicaldomain/wp-c.../11/mod3-1.jpg

Those shiny small boxes called “performance modules” that comes for a variety of models and model years, mostly with 4 wires coming out of it or even with a power select switch or rotary power control are the same cheap resistor, boxed, given fake attributes and some of them added a fancy control (variable resistor or potentiometer) along with the fixed resistor or a switch to select from different resistor values or “power ranges”.People no longer wanted to buy a 10 cents resistor for $15-$70, so they boxed it to make it look cool and hide it at the same time to avoid recognition, making people think that it is something way much more sophisticated than a simple, cheap and most of the times, non working resistor. Some sellers went farther than that, making people believe that the resistor was “tuned” specifically for your car model. There is no way of tuning a fixed part! Others use a resistor network chip and wire two of the leads to the outside of the box. Those chips are not semiconductors or anything alike. They just have several internal resistors in parallel of the same resistance value to save space in circuits. They just hook one of the internal resistors to the IAT.The results, the same of the resistor alone… NOTHING!Update:

Many people is asking me about what’s inside of the adjustable boxes. The truth is that it is all the same and results won’t change, but to satisfy everybody’s curiosity, they just add a variable resistor or “potentiometer”.It is used to adjust the total resistance of the circuit. That is, instead of having a fixed 4.7K resistor as a total and absolute value, it is made adjustable by placing a potentiometer in series with the circuit.Below is an example of this. In this picture, it is shown both pictorial and schematic versions for better understanding, along with direction of maximum and minimum resistance.This time it is selected a resistor with lower value to be fixed as the minimum circuit value. That is, if the person doing the scam knows what he is doing.In this case, minimum resistance will be the value of the fixed resistance, which is 220 ohms (equals to hot incoming air) and can be adjusted by turning the potentiometer all the way up to the sum of both resistors, which in this case will be 220+10,000 ohms = 10220 ohms, making it equivalent to very low temperatures.http://qcwo.com/technicaldomain/wp-c...stable_iat.jpg

Well, I don’t know about you, but I think this can called “IAT Module Demystified”…You are welcome to leave comments.Thanks for reading,Copyright www.technicaldomain.netFor real performance chips (not resistors) that will make your car pull real hard, visit the page below:www.otherdeal.comThese are real and tested. Trust us when we are saying that you won’t find anything alike on internet. We will soon post about the truth about big chip companies. Keep “tuned”.Also Interesting…

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Caribe 11 Second Club Garage is empty, add now http://ls1tech.com/forums/image.php?...ine=1155329247 Trader Rating: 1 Join Date: Dec 2003 Location: Kemah, TX. Posts: 639 http://www.ls1tech.com/forums/images/misc/im_aim.gif

http://images.ibsrv.net/ibsrv/res/sr...cons/icon1.gif Both of you guys are correct, there are two ways to do the IAT mod. 1-To trick the pcm that it is colder thus increasing timing(4.7 ohm, 1/2 watt resistor): http://www.installuniversity.com/ins...sity/index.htm look under computer/diagnostics 2-To trick the pcm to think it is warmer thus retarding timing(using nitrous etc)750 ohm resistor: http://www.robertsnitrousservice.com/n20wiring.htm Thanks to Robert56 for the link. Search timing tricker __________________ 2001 Pewter Trans Am Ws6 A4 w/ 3.23 gears, LME 408, SLP lidw/ powershot filter, 160 thermo, BBK TB, Jet-hot hooker headers through custom ory, Borlamouth, BMR SFC, BMR DS loop, UMI LCA's , March Pulley, TCI SSF3500 w/ Trans Go shift kit, MAC rear girdle. HSW wet kit, G-FORCE tune Last edited by Caribe; 09-20-2008 at 11:25 PM..

Quote:

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Originally Posted by wysemunky

would the heater hose mod count? It doesn't add any power or performance really, but it can improve the looks of the car. It doesn't cost anything if you have some sort of hose laying around that fits around the spring. I used the hose from the AIR pump delete.

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Some sources claim a 8hp gain over stock on a fully warmed up motor. Theres no point heating the throttlebody unless you live in the s pole where it keeps the tb plate from freezing shut. A cooler intake= win. less hoses to leak= win.
on 5.0 mustangs this thing can leak into your intake making you think you have a blown head gasket:P
you are talking about the tb coolant by pass? what spring? hmm that's not part of the tb bypass

I believe he was talking about the putting the heater hose around the rear springs (free suspension mod!) Gives a little better stance, have not done so yet but plan too. And thank u for all the IAT info!

http://ls1tech.com/forums/suspension...writeup-6.html

I bought some 3.9k 1/2watt resistors today at radio shack for like $1.10 for 4. Ill probably do the knock sensor mod tomorrow and data log. Im looking at all the tables in tuner pro right now as far as all the knock retard stuff and low octane. I may try to tune it too. I'm pretty sure i can live without a knock sensor to protect my stock motor. Alot of cars didnt have knock sensors. 5.0 mustangs didnt that I recall. Theres alot of things that can cause false knock and this will really cut into your performance. So Ill let you guys know how it goes. I know alot of people dont care because their cars are so heavily modded. My intent here was to bring together some good info in one place for people that wanna try stuff and dont have any extra money. If anyone else want to add to this feel free.

the knock sensor mod works amazing, but i totaled the car and hour later it worked so good