"Free Mods" for TPI cars
05-04-2009, 01:32 AM
#1
"Free Mods" for TPI cars
There's not much that's really "free" but if you're doing maintainence, here's some freebies.
Btw, to give credit where credit is due, all of this is taken from How to Tune and Modify Chevrolet Fuel injection by Ben Watson and he seems to credit TPIS for all this info.
-Trim the air filter lid so all of your air filter is exposed, thereby eliminating the air cleaner's lid asa restriction to airflow through the filter.
-High Flow Air filters ie. K&N etc.
-Remove the screens from your MAF sensor-be careful though, because if you break the wire inside, you'll have to pay $300-400 for a new MAF sensor. And the back screen is supposed to protect it from your engine backfiring, so you may want to just remove the front screen. Some people on the board even take out the cooling fins, but IMO, too much work for too little gain.
-640 Ohm Coolant sensor trick
Cost:
$0.20
How to:
disconnect the Coolant Temperature Sensor from the harness and install a 640 ohm resister across the terminals of the harness.
Why it works:
The 640 ohms tells the computer that he engine is not warmed up yet, so the computer will allow more advance since it does not expect detonation when the perceived engine temperature is only about 150 degrees F. Result = similar to recurving a distributer, rejetting the carburetor and making valve refinements.
Success depends on: initial timing adjusted properly and 92 octane fuel because you may get detonation on low octane fuel doing this.
Cons and Caution:
-Torque converter clutch may not work because torque converter lock up is inhibited at temperatures below 150 degrees F. Prolonged operation without torque converter lock up can cause the internal temperatures of the transmission to increase resulting in potential damage.
Best used on:
The track. And then take the resister out and reinstall it into the coolant temperature Sensor for daily driving.
160 degree thermostat:
Cost:
Less than $60, maybe more like $20 but I like Mr. Gasket brand thermostats because they are tested to be more consistent in temperature accuracy.
How to:
Buy a 160-180 Degree thermostat and install it.
Why it works:
See this link https://www.thirdgen.org/160-degree-...tat-tpi-engine
It has the same effect as a 640 ohm resister, allowing additional advance and a richer mixture with the Oxygen sensor. Also allows lower engine temperature resulting in less heat being transferred to the intake manifold so air remains denser and colder. Also lower air charge temperature lowers combustion chamber temperatures wich helps reduce detonation wich would cause the electronic spark control system to retard timing-thus reducing pwoer.
Success depends on:
Again, gas quality as you are advancing timing. Also on some part, quality of thermostat and installation
Cons and Cautions:
Again see this article https://www.thirdgen.org/160-degree-...tat-tpi-engine
-Overcooling = too rich = destruction of Catalytic converter
-Same problem regarding torque converter, air and egr not reading the correct engine temperature to work propery
-You may fail a sniffer test as your CO and HC levels will increase and you may fail any smog test.
Alternative:
180 degree thermostat. It costs the same, without all the cons.
Best used on
With a 180 degree thermostat, the street.
Power Fan Switch
-Along the same lines above in getting your engine to run colder to trick the computer to advance the timing, you can install a switch that turns the fan on at around 176 degrees F. and off at 166 degrees F. However the PROM does control the Fan. So, you may have to get a manual switch. Really though, if you have a 180 degree thermostat, you should be ok. This just helps the process along faster. Especially if you live in the southern states.
See this link:
https://www.thirdgen.org/manual-control-engine-fans
MAP Sensor Delay Valve:
Costs:
$2-10 for butt connectors, a little more for Vacum delay valves. Find a vacuum delay of about 1 second from a 1976-1984 Ford as vacuum delays were vital in Ford's emission program from those year.
How to:
Install a butt connector or vacum delay valve in the vacuum hose between the manifold and MAP sensor.
Why it works:
When the engine comes under a load-ie. When you accelerate, manifold pressure increases (vacuum drops.) The increasing manifold pressure signal from the MAP causes the ECM to retard the timing to lower combustion temperatures, reducing detonation and the possibility of NOx emmissions.
Installing a short delay vacuuum delay device in the vacuum hose between the manifold and the MAP sensor can slow the increase in pressure to the MAP and allow the timing to advance faster.
Cons and Cautions:
The MAP also performs the power valve function for the ECM, if there is too much of a delay, the air fuel ratio will not enrich fast enoug and the car will stumble or hesitate.
Alternative:
After going through the expnese of trying several vacuum delays you may find none of them significanlty increase power. It could be that to achieve what you are trying to accomplish, all that is needed is a restriction in the MAP sensor vacuum hose. So you may just want ot play around with the Vacuum line and electrical butt connectors.
Best used on:
The track as you can install and remove the connector or vacuum delay valve easily at the track. Although Ford did use a vacuum delay valve in many cars from the late 70's and early 80's so you may be able to keep the right delay valve installed on the street.
Port Plenum and gasket match plenum and runners:
Costs: $20-80 for 2 new gasket sets-I dont like reusing gummed up gaskets. Make sure they are the same dimension from the same manufacturer. $10 for a can of machinest blue. $6-20 for dremel bit. $30-80 for a dremel. A few hours and a lot of patience
How to:
See this thread https://www.thirdgen.org/forums/tpi/...num-whats.html
Spray machinest blue on your gaskets (if you plan to port match to the intake manifold, you'll need more than a dremel-or a lot of patience and cartridge rolls, so really this project is only for the plenum and runners.). Install and torque down plenum and runners. Take off plenum and runners. See where machines blue doesn't match on the plenum. Grind away slowly. Blow or vacuum away any grinding dust-this is important because if you don't it will go into your engine. Personally I'll take the time to spray this with brake clean or carb clean and wash everything in a parts washer and then vacuum again to make sure there is no grinding dust left behind that could go into the engine on reassebly.
Port the Plenum:
https://www.thirdgen.org/forums/tpi/...num-whats.html
This article has a small bit on porting your plenum https://www.thirdgen.org/trackside_t...gmhtp_jan_1999
Clean your plenum. Reinstall with new gaskets on car.
Why it works:
You are doing what most high flow runners are trying to achieve and more. Increase runner and plenum volume so that you can spin your engine 200-300 rpm high and fill the cylinders with more air at the higher RPM, thus moving the torque curve and horsepower curve up.
Cons and Cautions
You can ruin a plenum or runner if you grind away too much and if you don't make sure all the parts are free of ginding dust afterwards, it will end up in the engine. Also, make sure you wear a saftey shield and dust mask because aluminum gets pretty fine when you grind it.
Alternative
Spend $300-600 on High flow runners and have a machinist port match that to your plenum'
Best used
Anytime! Track or street.
Typical reward for all your hard work can be found in this article:
https://www.thirdgen.org/trackside_t...gmhtp_jan_1999
Spend a little more, get a bit more-not a little, but a bit more than a little.
-Airfoil over throttle body
-1.6 rockers
-*HEADERS, preferably 1-3/4"* -very worthwhile
-adjustable fuel pressure regulator, bumped up 10-12% from stock if you want to keep stock computer chip and save yourself the extra $300+ on a new chip/computer.
-pocket port your own stock heads
-port match plenum and runners-be careful because stock runners made of cast aluminum and you can remove too much. Definately use patience and a dremel slowly and with light grit. (the $300 or so on high flow runners for an extra 200-300 rpm aren't worth it IMO. It would be better spent on headers.)
-"performance" chip-may be questionable IMO and only is required after major changes ie. a Cam over .500 lift., heads, anything that requires more fuel to be pumped into the engine ie. NOS, turbo etc. and timing recurved to take advantage of it. But that's just my humble opinion.
Spend this amount and make sure you get enough fuel in, get a lot
-NOS kit and everything involved to get it to work without blowing up your engine.
-High performance heads and cam. Pick your poison and keep in mind a TPI system limits peak power to about 5000rpm and below.
Btw, to give credit where credit is due, all of this is taken from How to Tune and Modify Chevrolet Fuel injection by Ben Watson and he seems to credit TPIS for all this info.
-Trim the air filter lid so all of your air filter is exposed, thereby eliminating the air cleaner's lid asa restriction to airflow through the filter.
-High Flow Air filters ie. K&N etc.
-Remove the screens from your MAF sensor-be careful though, because if you break the wire inside, you'll have to pay $300-400 for a new MAF sensor. And the back screen is supposed to protect it from your engine backfiring, so you may want to just remove the front screen. Some people on the board even take out the cooling fins, but IMO, too much work for too little gain.
-640 Ohm Coolant sensor trick
Cost:
$0.20
How to:
disconnect the Coolant Temperature Sensor from the harness and install a 640 ohm resister across the terminals of the harness.
Why it works:
The 640 ohms tells the computer that he engine is not warmed up yet, so the computer will allow more advance since it does not expect detonation when the perceived engine temperature is only about 150 degrees F. Result = similar to recurving a distributer, rejetting the carburetor and making valve refinements.
Success depends on: initial timing adjusted properly and 92 octane fuel because you may get detonation on low octane fuel doing this.
Cons and Caution:
-Torque converter clutch may not work because torque converter lock up is inhibited at temperatures below 150 degrees F. Prolonged operation without torque converter lock up can cause the internal temperatures of the transmission to increase resulting in potential damage.
Best used on:
The track. And then take the resister out and reinstall it into the coolant temperature Sensor for daily driving.
160 degree thermostat:
Cost:
Less than $60, maybe more like $20 but I like Mr. Gasket brand thermostats because they are tested to be more consistent in temperature accuracy.
How to:
Buy a 160-180 Degree thermostat and install it.
Why it works:
See this link https://www.thirdgen.org/160-degree-...tat-tpi-engine
It has the same effect as a 640 ohm resister, allowing additional advance and a richer mixture with the Oxygen sensor. Also allows lower engine temperature resulting in less heat being transferred to the intake manifold so air remains denser and colder. Also lower air charge temperature lowers combustion chamber temperatures wich helps reduce detonation wich would cause the electronic spark control system to retard timing-thus reducing pwoer.
Success depends on:
Again, gas quality as you are advancing timing. Also on some part, quality of thermostat and installation
Cons and Cautions:
Again see this article https://www.thirdgen.org/160-degree-...tat-tpi-engine
-Overcooling = too rich = destruction of Catalytic converter
-Same problem regarding torque converter, air and egr not reading the correct engine temperature to work propery
-You may fail a sniffer test as your CO and HC levels will increase and you may fail any smog test.
Alternative:
180 degree thermostat. It costs the same, without all the cons.
Best used on
With a 180 degree thermostat, the street.
Power Fan Switch
-Along the same lines above in getting your engine to run colder to trick the computer to advance the timing, you can install a switch that turns the fan on at around 176 degrees F. and off at 166 degrees F. However the PROM does control the Fan. So, you may have to get a manual switch. Really though, if you have a 180 degree thermostat, you should be ok. This just helps the process along faster. Especially if you live in the southern states.
See this link:
https://www.thirdgen.org/manual-control-engine-fans
MAP Sensor Delay Valve:
Costs:
$2-10 for butt connectors, a little more for Vacum delay valves. Find a vacuum delay of about 1 second from a 1976-1984 Ford as vacuum delays were vital in Ford's emission program from those year.
How to:
Install a butt connector or vacum delay valve in the vacuum hose between the manifold and MAP sensor.
Why it works:
When the engine comes under a load-ie. When you accelerate, manifold pressure increases (vacuum drops.) The increasing manifold pressure signal from the MAP causes the ECM to retard the timing to lower combustion temperatures, reducing detonation and the possibility of NOx emmissions.
Installing a short delay vacuuum delay device in the vacuum hose between the manifold and the MAP sensor can slow the increase in pressure to the MAP and allow the timing to advance faster.
Cons and Cautions:
The MAP also performs the power valve function for the ECM, if there is too much of a delay, the air fuel ratio will not enrich fast enoug and the car will stumble or hesitate.
Alternative:
After going through the expnese of trying several vacuum delays you may find none of them significanlty increase power. It could be that to achieve what you are trying to accomplish, all that is needed is a restriction in the MAP sensor vacuum hose. So you may just want ot play around with the Vacuum line and electrical butt connectors.
Best used on:
The track as you can install and remove the connector or vacuum delay valve easily at the track. Although Ford did use a vacuum delay valve in many cars from the late 70's and early 80's so you may be able to keep the right delay valve installed on the street.
Port Plenum and gasket match plenum and runners:
Costs: $20-80 for 2 new gasket sets-I dont like reusing gummed up gaskets. Make sure they are the same dimension from the same manufacturer. $10 for a can of machinest blue. $6-20 for dremel bit. $30-80 for a dremel. A few hours and a lot of patience
How to:
See this thread https://www.thirdgen.org/forums/tpi/...num-whats.html
Spray machinest blue on your gaskets (if you plan to port match to the intake manifold, you'll need more than a dremel-or a lot of patience and cartridge rolls, so really this project is only for the plenum and runners.). Install and torque down plenum and runners. Take off plenum and runners. See where machines blue doesn't match on the plenum. Grind away slowly. Blow or vacuum away any grinding dust-this is important because if you don't it will go into your engine. Personally I'll take the time to spray this with brake clean or carb clean and wash everything in a parts washer and then vacuum again to make sure there is no grinding dust left behind that could go into the engine on reassebly.
Port the Plenum:
https://www.thirdgen.org/forums/tpi/...num-whats.html
This article has a small bit on porting your plenum https://www.thirdgen.org/trackside_t...gmhtp_jan_1999
Clean your plenum. Reinstall with new gaskets on car.
Why it works:
You are doing what most high flow runners are trying to achieve and more. Increase runner and plenum volume so that you can spin your engine 200-300 rpm high and fill the cylinders with more air at the higher RPM, thus moving the torque curve and horsepower curve up.
Cons and Cautions
You can ruin a plenum or runner if you grind away too much and if you don't make sure all the parts are free of ginding dust afterwards, it will end up in the engine. Also, make sure you wear a saftey shield and dust mask because aluminum gets pretty fine when you grind it.
Alternative
Spend $300-600 on High flow runners and have a machinist port match that to your plenum'
Best used
Anytime! Track or street.
Typical reward for all your hard work can be found in this article:
https://www.thirdgen.org/trackside_t...gmhtp_jan_1999
Spend a little more, get a bit more-not a little, but a bit more than a little.
-Airfoil over throttle body
-1.6 rockers
-*HEADERS, preferably 1-3/4"* -very worthwhile
-adjustable fuel pressure regulator, bumped up 10-12% from stock if you want to keep stock computer chip and save yourself the extra $300+ on a new chip/computer.
-pocket port your own stock heads
-port match plenum and runners-be careful because stock runners made of cast aluminum and you can remove too much. Definately use patience and a dremel slowly and with light grit. (the $300 or so on high flow runners for an extra 200-300 rpm aren't worth it IMO. It would be better spent on headers.)
-"performance" chip-may be questionable IMO and only is required after major changes ie. a Cam over .500 lift., heads, anything that requires more fuel to be pumped into the engine ie. NOS, turbo etc. and timing recurved to take advantage of it. But that's just my humble opinion.
Spend this amount and make sure you get enough fuel in, get a lot
-NOS kit and everything involved to get it to work without blowing up your engine.
-High performance heads and cam. Pick your poison and keep in mind a TPI system limits peak power to about 5000rpm and below.
05-04-2009, 07:00 PM
#2
Re: "Free Mods" for TPI cars
Not really a fan of a lot of that info. Not really a fan of the "don't tune your car properly, instead trick it by sending it misinformation" approach to hotrodding.
If I can quote Kelly Mcgillis:
These tricks may be a success, but I think we've shown them to be an example of what NOT to do.
OK, not an exact quote but....
If I can quote Kelly Mcgillis:
These tricks may be a success, but I think we've shown them to be an example of what NOT to do.
OK, not an exact quote but....
05-04-2009, 07:09 PM
#3
Re: "Free Mods" for TPI cars
Not really a fan of a lot of that info. Not really a fan of the "don't tune your car properly, instead trick it by sending it misinformation" approach to hotrodding.
If I can quote Kelly Mcgillis:
These tricks may be a success, but I think we've shown them to be an example of what NOT to do.
OK, not an exact quote but....
If I can quote Kelly Mcgillis:
These tricks may be a success, but I think we've shown them to be an example of what NOT to do.
OK, not an exact quote but....
Unfortunately, nothing in life is totally free...but that's why I added the cons of every trick.
05-04-2009, 07:12 PM
#4
Supreme Member
Join Date: Aug 2004
Location: Norwich, CT
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Car: '89 Trans AM/'88 GTA
Engine: (2) Tuned Port L98's
Re: "Free Mods" for TPI cars
where'z the hondo or goose love? 
I do like the cooling fan suggestions, Arizona is a car killer.
You have to do what you have to do sometimes to get to work!
But I agree with Abubaca, we should not promote such behavior.
I do like the cooling fan suggestions, Arizona is a car killer.
You have to do what you have to do sometimes to get to work!
But I agree with Abubaca, we should not promote such behavior.
Last edited by TPI; 05-04-2009 at 07:21 PM. Reason: ^ ^
05-04-2009, 09:40 PM
#5
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Join Date: Jun 2005
Location: Savannah GA
Posts: 502
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Car: 1986 IROC
Engine: 355" TPI
Transmission: 700R4
Axle/Gears: 3.42
Re: "Free Mods" for TPI cars
The resistor trick is crap. You are fooling yourself if you think doing this is going to work well. If you want to change the timing and fuel maps reprogram the ecu.
05-05-2009, 02:56 AM
#7
Re: "Free Mods" for TPI cars
Hey. I never said it was the correct way. Everyone that knows anything about tuning knows that the "right" way is to reprogram the timing and fuel map. And darn skippy you're damn right, this is about tricking the stock ECU the "wrong" way by manipulating the sensors that input data into the computer.
Not something recommended if you're daily drving with some of the "free mods". But something you can do at a track quickly without spending $200-800 for a prom burner or $300 for a mega-squirt computer. And then returning the computer back to the stock timing and fuel map by removing a resister or butt connector.
The correct way is to reprogram the ECU or PROM it just cost more $$$ that's all. And time if you want to learn to do it yourself. Just like porting. But this is an awesome thread on programing https://www.thirdgen.org/forums/tpi/...-also-tps.html and the guide at the DIY Prom section of the board.
The only reason I wrote this post was because of another post where someone asked about "free" mods because they were in college and didn't have a lot of cash to burn.
With any mod, even "free" mods, there's always going to risks.
Here's and interesting opinion on what could go wrong with MAF screen removal. Code 33.
http://gmtips.com/3rd-degree/dox/tip...maf-screen.htm
Another relatively "Free" mod was written by Vader. I've never tried this one, but his article on building your own AFPR was interesting.
http://gmtips.com/3rd-degree/dox/tips/afpr/afpr.htm
Instead of complaining, I just wish someone on this board would write a proper "free" mod thread. Oh, instead of b*tching and complaining no one wants to write a proper thread on "safe" "free" mods. Or even take the time to compile all the "free" mods on the board that everyone has tried and found relatively harmless.
It's not like the disclaimer of what could go wrong with each mod is not listed. Use at your own risk and if you find that you picked up a tenth or hundreth of a second for less than $1, don't forget to take out that resister out when you leave the track.
Not something recommended if you're daily drving with some of the "free mods". But something you can do at a track quickly without spending $200-800 for a prom burner or $300 for a mega-squirt computer. And then returning the computer back to the stock timing and fuel map by removing a resister or butt connector.
The correct way is to reprogram the ECU or PROM it just cost more $$$ that's all. And time if you want to learn to do it yourself. Just like porting. But this is an awesome thread on programing https://www.thirdgen.org/forums/tpi/...-also-tps.html and the guide at the DIY Prom section of the board.
The only reason I wrote this post was because of another post where someone asked about "free" mods because they were in college and didn't have a lot of cash to burn.
With any mod, even "free" mods, there's always going to risks.
Here's and interesting opinion on what could go wrong with MAF screen removal. Code 33.
http://gmtips.com/3rd-degree/dox/tip...maf-screen.htm
Another relatively "Free" mod was written by Vader. I've never tried this one, but his article on building your own AFPR was interesting.
http://gmtips.com/3rd-degree/dox/tips/afpr/afpr.htm
Instead of complaining, I just wish someone on this board would write a proper "free" mod thread. Oh, instead of b*tching and complaining no one wants to write a proper thread on "safe" "free" mods. Or even take the time to compile all the "free" mods on the board that everyone has tried and found relatively harmless.
It's not like the disclaimer of what could go wrong with each mod is not listed. Use at your own risk and if you find that you picked up a tenth or hundreth of a second for less than $1, don't forget to take out that resister out when you leave the track.
Last edited by Nelz; 05-05-2009 at 12:13 PM.
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05-05-2009, 10:26 PM
#10
Re: "Free Mods" for TPI cars
If someone asks for "free" mods, then a response is just fine.
...but every thirdgen owning red neck hacks up their MAF screens and starts spouting things like they KNOW what they're talking about. (not saying you). ...and after YEARS AND YEARS of reading and learning and trial and error, I've learned that if the mod is described in any way as FREE...it's typically a hack that does nothing, or worse, can cause damage. Add up all the horsepower of those free mods and I doubt it's more than 2 or 3 at the very best.
I just hate free mod threads.
Free mod:
Remove your air filter. Honestly, it's probably the BIGGEST gain of any listed.
Nothing personal Nelz, it's just a pet peeve.
...but every thirdgen owning red neck hacks up their MAF screens and starts spouting things like they KNOW what they're talking about. (not saying you). ...and after YEARS AND YEARS of reading and learning and trial and error, I've learned that if the mod is described in any way as FREE...it's typically a hack that does nothing, or worse, can cause damage. Add up all the horsepower of those free mods and I doubt it's more than 2 or 3 at the very best.
I just hate free mod threads.
Free mod:
Remove your air filter. Honestly, it's probably the BIGGEST gain of any listed.
Nothing personal Nelz, it's just a pet peeve.
05-06-2009, 02:04 AM
#11
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Car: 1991 camaro RS
Engine: CharlesOdoryOB
Transmission: 82513892892
Axle/Gears: pbr disc 3.27 nine bolt
Re: "Free Mods" for TPI cars
some of these free mods are only for the track and can be illegal on the street .
throttle body coolent delete/bypass
remove ac
remove rear seats or any other unneeded interior parts
remove front swaybar track only
tire pressure 34-36 psi front 28-24 rear track only
remove muffler gets loud but only as loud as aftermarket exhausts but can have annoying sound to it
remove air filters track only
gut the lower air cleaner boxes camaros or firebirds remove the houseing so the air filter is by itself looks pretty much like an aftermarket cai then
drain wiper fluid out track only some people even drain some coolent out to lose some weight ive never done the coolent thing
keep to a max of 1/8 tank at the track
remove the walls inside the plenum right behind the throttle bores
put bolts with washers into the 3 holes on the lower control arms and tighten down a bit .
car bites off the line a bit harder and with more control ,
or weld on a peice of steel to box them i did both
you can also mod the Throttle valve pluger housing in the trans to hold 4th gear with out always down shifting to 3rd . works best with a corvette servo
but it can help on its own. but can burn up the trans with out vette servo for prolonged 4th gear high speed operation.
remove smog pump and all related air injection "illegal" frees up some lost hp some weight loss off road use only
unplug the knock sensor track only i noticed my car pulls much harder at freeway speeds with it disconnected or having the wrong part installed lol. "tbi knock after tpi swap throws a code"
i also notice the car had a bit more pull with the vss disconnected and lost 3 tenths at the track , no clue why i gained 3 tenths but ive repeated at the track a few times.
pretty much all the free mods work by getting the car to hook better
shead weight or free up some minor hp.
ill bet there are alot more mods out there but they all do one of these things.
there is not one free mod that makes a huge differance on its own but combine them and you notice a differance in track times.
only real way to compare anyway
i took a full second off my 1/4 mile times with everything i did for free
the car can launch harder and grips better off the line where tpi needs all the help it can get.
there really is no substute for real mods like headers full exhaust head, cam swaps
cheap but not free mods
used aluminum driveshaft from 3rd or 4th gen lighter and engine revs alittle faster and smoother ride
vette servo more apply pressure for the trans is always good
air foil not sure how much it really helps but i got one free
1.6 rockers full roller or not increase lift and free up some friction and give a noticeible increase in power is nice but can be pricy did make 16 extra hp with the stock peanut cam and 12 torque
rear end gear swap real seat of the pants differance one biggest increases for cost and i only went from 2.73 to 3.23 if i did it over id go to 3.42 for 305 cars
poly bushings and endlinks car handles better
also not to expensive is subframe connectors real differance in the way the car rides so much more solid.
headers can be expensive but seem to be the on the same hand as a gear swap huge differance in sound and power output they are something thats worth the investment . made 14 more ponys and 20 more torque with edelbrock's that everyone around here hates
underdrive pulleys i got a set from summit clearance rack for 25 bucks still need a new serp belt i really didnt notice much of a differance sadly but i didnt use the alt pulley as it keep dimming the lights
but a dyno pull said i gained 3 hp lol.
throttle body coolent delete/bypass
remove ac
remove rear seats or any other unneeded interior parts
remove front swaybar track only
tire pressure 34-36 psi front 28-24 rear track only
remove muffler gets loud but only as loud as aftermarket exhausts but can have annoying sound to it
remove air filters track only
gut the lower air cleaner boxes camaros or firebirds remove the houseing so the air filter is by itself looks pretty much like an aftermarket cai then
drain wiper fluid out track only some people even drain some coolent out to lose some weight ive never done the coolent thing
keep to a max of 1/8 tank at the track
remove the walls inside the plenum right behind the throttle bores
put bolts with washers into the 3 holes on the lower control arms and tighten down a bit .
car bites off the line a bit harder and with more control ,
or weld on a peice of steel to box them i did both
you can also mod the Throttle valve pluger housing in the trans to hold 4th gear with out always down shifting to 3rd . works best with a corvette servo
but it can help on its own. but can burn up the trans with out vette servo for prolonged 4th gear high speed operation.
remove smog pump and all related air injection "illegal" frees up some lost hp some weight loss off road use only
unplug the knock sensor track only i noticed my car pulls much harder at freeway speeds with it disconnected or having the wrong part installed lol. "tbi knock after tpi swap throws a code"
i also notice the car had a bit more pull with the vss disconnected and lost 3 tenths at the track , no clue why i gained 3 tenths but ive repeated at the track a few times.
pretty much all the free mods work by getting the car to hook better
shead weight or free up some minor hp.
ill bet there are alot more mods out there but they all do one of these things.
there is not one free mod that makes a huge differance on its own but combine them and you notice a differance in track times.
only real way to compare anyway
i took a full second off my 1/4 mile times with everything i did for free
the car can launch harder and grips better off the line where tpi needs all the help it can get.
there really is no substute for real mods like headers full exhaust head, cam swaps
cheap but not free mods
used aluminum driveshaft from 3rd or 4th gen lighter and engine revs alittle faster and smoother ride
vette servo more apply pressure for the trans is always good
air foil not sure how much it really helps but i got one free
1.6 rockers full roller or not increase lift and free up some friction and give a noticeible increase in power is nice but can be pricy did make 16 extra hp with the stock peanut cam and 12 torque
rear end gear swap real seat of the pants differance one biggest increases for cost and i only went from 2.73 to 3.23 if i did it over id go to 3.42 for 305 cars
poly bushings and endlinks car handles better
also not to expensive is subframe connectors real differance in the way the car rides so much more solid.
headers can be expensive but seem to be the on the same hand as a gear swap huge differance in sound and power output they are something thats worth the investment . made 14 more ponys and 20 more torque with edelbrock's that everyone around here hates
underdrive pulleys i got a set from summit clearance rack for 25 bucks still need a new serp belt i really didnt notice much of a differance sadly but i didnt use the alt pulley as it keep dimming the lights
but a dyno pull said i gained 3 hp lol.
05-06-2009, 06:55 AM
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Car: 1986 IROC
Engine: 355" TPI
Transmission: 700R4
Axle/Gears: 3.42
Re: "Free Mods" for TPI cars
If someone asks for "free" mods, then a response is just fine.
...but every thirdgen owning red neck hacks up their MAF screens and starts spouting things like they KNOW what they're talking about. (not saying you). ...and after YEARS AND YEARS of reading and learning and trial and error, I've learned that if the mod is described in any way as FREE...it's typically a hack that does nothing, or worse, can cause damage. Add up all the horsepower of those free mods and I doubt it's more than 2 or 3 at the very best.
I just hate free mod threads.
Free mod:
Remove your air filter. Honestly, it's probably the BIGGEST gain of any listed.
Nothing personal Nelz, it's just a pet peeve.
...but every thirdgen owning red neck hacks up their MAF screens and starts spouting things like they KNOW what they're talking about. (not saying you). ...and after YEARS AND YEARS of reading and learning and trial and error, I've learned that if the mod is described in any way as FREE...it's typically a hack that does nothing, or worse, can cause damage. Add up all the horsepower of those free mods and I doubt it's more than 2 or 3 at the very best.
I just hate free mod threads.
Free mod:
Remove your air filter. Honestly, it's probably the BIGGEST gain of any listed.
Nothing personal Nelz, it's just a pet peeve.
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