cmdeshon

hello fellas!

i just recently bought a LT1 - T56 Firebird. its a 97. it seams to be running pretty good but i have a few questions.

first of all, it seams to run really cold. the temp gauge only moves up to about 1/8th when i am cruising. if i really beat on the car sometimes i can get it up to about 1/4th the way up the gauge. Should i be concerned about this? i am thinking that maybe the previous owner put a really low thermostat in. or maybe they just removed it all together... Where should the temp gauge usually sit?

my car is OBD2. and its bone stock. i am considering deleting a few things but i dont want to trip my Check Engine Light. if i were to delete all of my Cats, EGR and the Air pump. Is there some kind of resistor mod that i can do to fool the computer so that i dont throw a code?

i have heard that there is some kind of Plug-In doohicky that will disable the "skip-shift" ? can someone point me in the right direction? its pretty annoying (and seams fairly pointless)

and last of all, id really like to get shorter gears in the back. these 3.42's are really stupid with the 6-speed. i am thinking like 4.10's? or 4.30's? ish...... What is the best route? is there a complete stock axle that i can grab out of something else? or am i better off just buying an R&P and having mine rebuilt?

Thanks guys! i have a lot more lurking to do....

Injuneer

Stock thermostat is 180*F, and stock fan programming turns them on at 226*F (low speed) and 235*F (high speed). With the stock stup, you typically see the needle near the center of the gauge (210*F) at idle, sitting in traffic. At freeway speeds, you might see it in the range of 190-200*F.

Many people opt for a 160*F t'stat, with the fan "on" temps lowered appropriately. In that case you might see the temp gauge near the 1/4-mark (~185*F).

First question would be "why do you want to delete the emissions systems"? You might lose 5HP max with the cats; AIR only runs for a couple minutes at startup to heat the cats, then turns off; EGR does not operate at idle, not above 3,500RPM and not at WOT. So AIR and EGR have no impact on performance. If you want to delete them, you really need to have them programmed out of the PCM, by someone who knows how to prevent the "system not ready" flag for each system. You could delete the cats and install "O2 sims" that replicate the signal form the after-cat O2 sensors. They are a bit hit-or-miss, since the EPA declared them illegal, stopped Casper Electronics fro making them, and fined them $70,000. Probably need to look for them on ebay.

"Skip shift eliminator", about $30. Alternative - a 2Kohm resistor from Radio Shack, bending the end of the wires so they can be pushed into the terminals in the harness connector, and taped up. Cost - less than $1

Depends what you want. Most people are very satisfied with 4.10's. Building the stock 10-bolt up is a crap shoot. They are terminally weak, particularly behind a manual trans. Gears $200, install kit $80-120, labor $250-350. The alternative would be a ready-made, bolt-in 12-bolt from Strange or Moser, but now you are approaching $2,500-3,000. If you plan to go to the track and do high RPM clutch dumps on sticky tires, you need the 12-bolt. For normal street driving the 10-bolt will probably survive, if not abused.

Chimera96

quite possible the P.O. had PCM programmed for lower fan temps and a 160 T stat. With that the needle sits around "1/8" or above the 1st hash mark

as fred notes...leave the emission stuff alone, no real gain and if you do you need to re-program PCM to disable them to keep CEL from coming on. If you have emission testing...you won't pass with the stuff deleted

97WS6SCharged

There was a TSB to replace the air pump years ago. Most guys just remove them all together.

cmdeshon

thanks for the reply guys i appreciate it.

as for all the emissions stuff. as long as i can keep the CEL from popping on i can get by inspection. i am not in a Smog state and its just a "visual" for EGR and cats. i am really more interested in deleting the stuff just to make the car a little easier to work on. always nice to make a little bit more room. is the "o2 sim" just an inline resistor? is that something i could just make? (i was able to do that for the downstream o2 and the EGR on my 2JZ Supra engine)

i really just want 4.10's to make the car nicer to drive. the current gears are just useless with the six speed. i dont use 5th often and i never use 6th.... and i pretty much have to smoke my clutch in traffic. this car is currently my daily driver. i am not trying to put stickies on it and go launch at the track. but i do think 4.10's would be more fun, more sensible, and probably wouldn't have any negative effect on gas mileage.... Maybe even get slightly Better mpg's around town? i feel like with 4.10's id be able to get thru the friction zone without even using the gas peddle...

Injuneer

Some people use spark plug "anti-foulers" to defeat the after-cat O2 sensor code after removing the cats. You keep the sensor, but you use the plug extenders to move the sensor out of the exhaust stream. Some people report that eliminates the SES light/code. Never tried it, because my 94 doesn't have the after-cat sensors.

Spark Plug Non Fouler at AutoZone.com - Best Spark Plug Non Fouler Parts for Cars, Trucks & SUVS

I know the "sim" is not a simple resistor. The sensor, or sensor replacement has to produce a "dampened" version of the signal produced by the pre-cat sensor. Have no idea what works or doesn't work on the Supra.

Just to clarify, programming the PCM can eliminate the codes. And if done correctly, it overrides the "system not ready" flag that incorrect programming can produce. If they don't plug into the ALDL connector as part of the inspection procedure, the system flags will not matter. If they do plug in, various states and jurisdictions have different numbers of allowable "system not ready" flags they will permit before they fail you. It is definitely possible to pass emissions with a correctly reprogrammed PCM.

Personally, I built an 800HP LT1 and kept the emissions - cats (dropped out at the track to run leaded fuel), EGR, AIR and EVAP, at least until it became a "track" car.

Odd problem with the T56 and 3.42 gears. My Formula had that setup from the factory, and presented none of the problems you describe. It would get moving smoothly with no abuse of the clutch, accelerate well, smoking the tires at will, and 6th gear was very useful at 80 MPH on the freeway, producing more than 30 MPG.

cmdeshon

Again, Thank you for the informative response. i appreciate you guys taking the time to answer my questions.

here in NC it is very rare to find a speed limit higher than 55. if i could legally "cruise at 80" anywhere in my state than 6 might be more useable. there are a few 65MPH zones where i can ride 70 but thats the only time i ever even use 6th gear.

the car does still take off smoothly, and very much so smokes tire. and it pulls alright (most people would probably consider it a race car...) but my problem is more so like, in traffic. if theres a car in front of me and im only trying to get twenty or thirty feet, instead of being able to just let off of the clutch, i have to cook it in the friction-zone for a minute and step on it again. i feel like with a 4.10 id be able to let the clutch all the way out and let the car idle its way forward. maybe im just being picky....

i just installed a new Voltage Regulator in my alternator and the car is very happy. i think its reached the point of being a good reliable DD.

gona try to make my own skip shift eliminator in the next day or so. someone told me that i need a 2k Diode resistor. so i gotta find one of those out in the shop. il post up my results when i am done.

Injuneer

You don't need a "diode" resistor (whatever that is). You simply need a 2,000 ohm conventional resistor, as I explained in my first post. Exact value is not important... you are just completing the circuit with a "load" so the PCM does not see the wrong voltage on the circuit. Get the highest "watt" rating you can find, because it is replacing a 12V solenoid that probably draws at least an amp.

I would agree the 4.10's will be more fun. I opted for a replacement 12-bolt with 3.73's at first, and wished I had gone with the 4.11's. Hammered the crap out of the drivetrain, with a McLeod Street Twin and 5,000 RPM clutch dumps on slicks. Currently running 4.11's but with a TH400.

97WS6SCharged

Don't you have the Gear Vendors OD on that car also?

I'm in the process of converting my LT1 car to a 408 LS1 with a 4L80. Planning to run a 3.25 gear in the 9" with a 28" tire.

4.10's would probably do a little better in the mountains/hills. Last time I was up in Ashville I was seriously annoyed that every freaking traffic light seemed to be at the top of the hills instead of the bottom.

cmdeshon

a Diode resistor is like a normal resistor but it only flows one way. (i think....)

i guess it reduces Back-feed up the original wire? thats what i was told but i have nothing to back it up with. i spoke with a GM master electrical tech yesterday. it was actually completely by coincidence. he happened to be helping someone who was buying a Honda Prelude from me. saw the WS6 and was like, "Hey! is that a WS6 firebird?"

was pretty cool. he was able to answer a lot of my odd ball questions. i guess he works at a cadillac dealership and apparently does skipshift elimination for people on CTSV's and i think he said GTO's fairly often. he said on the newer cars if you dont use a diode resistor than it backfeeds up the wire and lights up every light on the radio.... lol (he didn't give me any background on that....)

i think those are all the Tremac 6-speed though. maybe its irrelevant on this firebird.

im going to try it Your way first Fred. i should already have tons of 2k resistors and i dont think i have any Diode resistors on hand.

Injuneer

All 93-02 V8 F-Bodies used basically the same 6-speed manual trans. From 93-97 it was built by Borg-Warner. Sometime in 97 B-W sold the design and the manufacturing facilities to Tremec, and they moved production to Mexico.

Seems odd asking for help when you feel you already know the answer. Do it your way. I'll leave you alone.

cmdeshon

i did not know the answer when i first asked. i have been reading a LOT. trying to decipher all of the information. learning as much as i can about the drivetrain and electronics. its all a lot different than what i am used to.

Your posts have been very informative and helpful.

GaryDoug

I believe the tech was referring to using a resistor with a diode for the skip shift indicator circuit, not the solenoid circuit. No diode is needed for the solenoid circuit. Even if you want to bypass the skip shift lamp on your car, no diode is needed. It's only on newer cars with the integrated instrument display panels

Chimera96

FWIW I did a 4L60E to T56 swap in my car. Had 3:73's in at the time and felt they should be fine. They were "ok" but I did have a slight bog starting especially on a incline like a driveway. My car weighs 4200+ lbs

switched to 4:10's and now the car just feels "right". With a 27" rear tire my RPM's at 80 mph in 6th are just under 2k RPM. On the street it is a 4 speed, FWY 5th unless I am going 65+ and not much traffic I shift into 6th.

Yes you can basically let out clutch at idle in traffic for smooth engagement...YMMV

cmdeshon

i used a 2.2K 3 amp resistor and it worked great.

car is now throwing an air-pump code and an EGR code. So, i am going to start looking into deleting more stuff. i think i may have someone local who can help me program stuff out of the computer but i want to make sure that they can do it before i start deleting stuff...

will Deleting EGR effect my fuel economy?