LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

*excellent info* 93 specific info list.

Old 02-21-2002, 01:09 AM
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Thumbs up *excellent info* 93 specific info list.

I have noticed a few posts about the differences that the 93's have. Soooo, here is a list that I have been working on for a while trying to find as many differences with the 93's as I can. If you have any other differences or corrections PLEASE let me know.

  • Non-vented Optispark until 1995
  • Does not have a MAF (it is speed density)
  • 93 had 2 different gearboxes. The M29 that came with the 3.23 car and the M28 that came with the 2.73 cars. Here are the transmission gear ratios:
    M28 M29 94+
    3.36 2.97 2.66 1st gear
    2.07 2.07 1.78 2nd gear
    1.35 1.43 1.30 3rd gear
    1.00 1.00 1.00 4th gear
    0.80 0.80 0.74 5th gear
    0.62 0.62 0.50 6th gear
  • For gear change - You must change the speedo gear in the tailshaft of automatics. The speedometers on the '93 A4's were not electronic like in later years. M6s require an electronic calibration box to correct speedo. However, the speedo can be corrected for 3.23 and numerically lower gears by modifying the eprom.
  • Headers/manifolds are different. EGR gasses are only taken from right above #8 cylinder. The tube above #1 is for air injection. (94+ have an extra hole on the passenger side for a 2nd A.I.R. input.
  • Fuel rails don't have a front x-over tube and thus use an intake manifold without the recess for it. The fuel line junction at the driver's side is near the TB instead of near the back (making it much easier to get at!).
  • 93s came with 22lb injectors instead of 24lb
  • The fuel system schrader valve is mounted on the drivers side fuel rail instead of behind the intake manifold.
  • 93s are usually more responsive to fuel pressure changes. It must have something to do with having a speed density system.
  • Heater hose has a T in it going to the throttle body and also in the upper radiator return hose until the 1995 model.
  • The front brakes are different. I believe the rotors and pads are smaller (unconfirmed). I can measure my front brakes if someone with a newer lt1 can measure theirs.
  • Fuel pressure regulator is mounted on the passenger side as opposed to being on the driver side for 94+. Thus requiring a 93 specific FPR. TPI AFPR's are also useable on 93's.
  • 93s have a non-electronically controlled 4L60 automatic transmission (internals are swappable with 700R4s).
  • The throttle body in an automatic equipped 93 has a connection for the TV cable. 94+ do not have the connection.
  • Pink rods instead of powdered metal rods (unconfirmed)
  • 1.46 valve springs instead of 1.25 in the newer LT1s (unconfirmed)
  • Oil pressure sender is directly above the oil filter instead of on the back of the intake manifold (unconfirmed that 94+ is on the manifold)
  • 93s have a metal fan on the CS 144 alternator and is rated @ 124 amps. The positive bat wire for it is attached with a bolt.
    The 94+ cars have a 140 amp alternator with a plastic fan. It uses a stud and nut to attach the positive 'BAT cable.
  • Hardened pushrods until 95
  • Traction control was not an option on 93's.
  • 93 Formulas and Trans Ams did not have the 'performance shift' option.
  • 93's only hold 4.5 quarts of engine oil according to the owners manual
  • 93's only have the A.I.R. pump mounted to the frame. Later years are mounted to the engine block.
  • 93 is the only year 4th Gen that you can flash the computer codes by using a jumper wire between pins A & B (upper right 2 pins)on the DLC (under dash next to steering column). After the jumper is installed turn the ignition to "on" (not start). The engine light will then flash the codes. A 12 code will be given at the beginning and the end of the sequence which just tells you that the self diagnostic is good.
  • O2 sensors have only one wire and they are not heated. If converting to long tube headers you will have to upgrade to later heated style O2 sensors to keep them hot because they are moved further back.
  • Removeable computer chip instead of reprogramable PCM. This is actually nice if you are a tuner since all you have to do to change programming is swap chips. Although, that makes it a little tougher to do your own custom programming, as it requires burning your own chips. There is very little information out there about doing this.
  • 1993 and early-1994 cars don't have dual speed fans making them much easier to put in a manual on switch. They have no #3 (J) fan relay. For these cars you can just ground D2 for the primary fan and F5 for the secondary one.
  • Batch fire injection (each pair of injectors fire simultaneously instead of individually) instead of port injection. No real detriment as far as performance or fuel mileage is concerned.
  • 93s dont have a provision for the lt4 knock module.
  • No CAGS on the M6 so you dont have to worry about the annoying skip shift feature!
  • Temp guage on 93's start at 100*. 94+ temp guages start at 160*
  • Wire harness for the fuel injectors is not tagged with the position # as newer model f-bods are.
  • The "change oil" light is not used on 93's
  • 93's do not have the oil cap extension tube. The cap is connected directly to the valve cover.
  • Pontiacs could get steering wheel radio controls.
  • Chevys f-car had Yellow highlighted switches and instrument cluster the Pontiacs did not
  • 93 Camaros do not have Camaro indented or printed on the passenger side air bag cover.
  • No stretchy stuff on the sun visors to hold things
  • 93s and 94s are the only ones with a dot-matrix pattern on the t-tops
  • Chevys Did not have leather as an option, but the Pontiacs did
  • convertible was not available as an option
  • Pace car option was available
  • All 93 Z28 Camaros came with black tops standard. V6's couldn't get them. In later years it became an option.
  • All 93 TA's had the GT package with leather & upper level wing

For the best information concerning a 93 F-body visit the NEW & IMPROVED Speed Density Board!

Last, but not least The 93s are just plain faster!

Still in question:
  • When did the change in wiper size come in to play?
  • What are the 93s front brake differences?
  • Do 93s have Pink rods?
  • Are the valve springs a different diameter than later model?
  • Can you correct the speedo for gearing other than 2.73s or 3.23s for 6-speeds by programming the chip?

My Valentines gift '01- Red 93 Z28 M6-
Trans roller pinion bearing, Rhino clutch, Flowmaster 3" cat back, K&N FIPK w/ S&B filter, intake baffle capped, Throttle body Airfoil, RK Sport Air Dam and Rear Spoiler, LS1 3" aluminum DS, !Radio option thanks to some punk!
Best time 14.101 @100.99

Last edited by chevroletfreak; 12-03-2003 at 08:07 PM.
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Old 02-21-2002, 02:25 AM
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You sure about the leaher?. My buddy had a 93Z and his had leather.Also I have a feeling my speedo is a little messed up from my 3.73's. One last thing what do us 93 guys want to set are AFPR's at?. I have one and haven't installed it because of this. Also no convertible in 93.Good fact sheet buddy. I love my 93 only 53,516 miles on the clock.

BEST 1/4:13.18 @ 105.96
BEST 60':1.949 Haven't installed:Trans-Go(sold it),SS SPOILER(arrived needs paint)
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Old 02-21-2002, 03:08 AM
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you are right about the convertible not being available. I have updated my list.

I am not positive about the leather, but am pretty sure. Hopefully someone else can help with that.

I have not worked with adjusting the fuel pressure so I cant offer any info on that. Sorry.

[This message has been edited by chevroletfreak (edited February 21, 2002).]
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Old 02-21-2002, 04:57 AM
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I am pretty sure leather interior wasn't introduced until about mid year on the 94s.

94 F1 Camaro
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Old 02-21-2002, 08:00 AM
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Thanks! Anyone else with any input?
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Old 02-21-2002, 08:27 AM
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On the dotted t-tops, my window sticker says solar ray tinted or something like that. I didn't know if it was a option or not. But I also have noticed on later year cars, that the t-tops are just tinted with no dots. Personally I like the dots. :-)

94Z28M6-BBK Headers & Y pipe,Hypertech 160stat,Hypertech airfoil,Hypertech PTM,B&M ripper,!fan switch,Hypertech underdriven,K&N FIPK,Borla,!TB bypass,SLP centerbolt wire looms,Taylor 8mm,1LE elbow,Cutout
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Old 02-21-2002, 08:31 AM
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You're pretty much right about all of that. There was NO leather and NO verts. However, T-Tops were available, but only in limited amounts near the end of the model year.

My 93 has every option except t-tops.

The Velvet Smog (93 Z28)
Modificationii: Borla, Hooker LTs, Dual Cutouts, MTI CAI, Meziere, PC Tranny Cooler, 160-stat, Tranny Temp gauge, and what not..
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Old 02-21-2002, 08:49 AM
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Don't gorget the 93 was the Indy Pace Car! The exhaust manifolds and AIR tubes are different on a 93 as well. The front brake pads and rotors are also unique to the 93. You couldn't get the 3.42 ratio with the 6 speed like you can with the 94 & up.

Jeff H (93 Indy Pace Car - Blown, Powerdyne 4.5, SVO 24# injectors, Borla y-pipe, Morflo cat, Flowmaster cat-back, SLP chip, 160 therm, 69 Z28 Hugger Orange, GM crossram, GM fiberglass cowl induction hood, factory TI setup & factory installed JL8 4 wheel disc brakes - original #'s matching and documented, being restored)
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Old 02-21-2002, 09:39 AM
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I think i might have to disagree with u guys about the leather step brother has a 93 formula and his has a tan leather interior, so i do believe that there was an option for leather because he did not have that installed.

1994 Teal Z28
Cowl Induction Hood
Hurst Short Throw
Edelbrock Headers
Adjustable Borla Cat-Back
17" Eagle wheels w/245 45 17 Kuhmo Supras
TB Bypass
Air Foil
160 degree thermostat
1LE High flow bellows
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Old 02-21-2002, 02:23 PM
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My next door neighbor has a 93 T/A and it has gray leather interior. He also did not have it put in there, it came from the factory like that.

94Z28M6-BBK Headers & Y pipe,Hypertech 160stat,Hypertech airfoil,Hypertech PTM,B&M ripper,!fan switch,Hypertech underdriven,K&N FIPK,Borla,!TB bypass,SLP centerbolt wire looms,Taylor 8mm,1LE elbow,Cutout
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Old 02-21-2002, 02:58 PM
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Dont know about the Camaro's, but I know forsure the 93 Formula/Trans Am's had the option for leather.


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Old 02-21-2002, 02:59 PM
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Camaros for sure did not have leather as an option for 93. Firebirds may have since it's Pontiac's flagship, so it would make sense (they also get better seats and stereo), but yeah everything else is correct. Good job!
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Old 02-21-2002, 03:01 PM
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Also, if you want to go into greater detail (considering what I posted above), you may want to seperate the 93 Camaro vs. 94+ Camaro and the 93 Pontiac vs. 94+ Pontiac.

For instance, the "yellow" speedo numbers were on the 93 Camaro's, but not on the 93 f-car Pontiac's.

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Old 02-21-2002, 03:10 PM
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What was the difference in the brakes? I've got a 93 6 cylinder and a 94 Z, but the slow six seems to stop a heck of a lot better.

The usual stuff......I guess......maybe....sure.
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Old 02-21-2002, 03:18 PM
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A few things...

- Like everyone else mentioned leather was available on the Pontiacs. The Pontiacs didnt get that fugly yellow lettering either.

- EGR gasses are only taken from right above #8 cylinder. The tube above #1 is for air injection only.

- 93's cant use a LT4 KM

- If you need info on burning chips head to Lotsa info there, its not really that hard either IMO.

- the non-vented opti is a 92-94 thing, not just 93's

- I'm pretty sure the "T" in the heater hoses was there till 95 or 96...

Thats about it, pretty good job so far

93 TA, M6
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