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

Where Iím at!?

Old 03-30-2019, 05:54 PM
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Where Iím at!?

Hello all, this is my first post here. I just recently got a 1994 Camaro Z28. The car is absolutely mint and has only 35,000 miles (60,000kms) on it! Iíve done a few little tweaks to it over the past 3 weeks and am curious where you think I am powerwise? Iíve swapped in a K&N air filter, SLP air foil, MagnaFlow 93444 Y-Pipe and Cat, MagnaFlow 15620 Cat-Back system. Crane Cams 1.6 Roller Rockers and a 125 HP Nitrous system with remote bottle opener. Iíve also changed the springs to Eibach 1.3Ē lowering and added in Competition Engineering Sub Frame connectors. I absolutely love the car!!!! Thank you ahead of time for your comments!

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Old 03-30-2019, 07:49 PM
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Re: Where Iím at!?

Some LT1 mod dyno tests:

WS6.COM LT1 Trans Am

Is your K&N just a filter panel in the stock box, or complete K&N cold air intake (CAI) system?

When looking at the dyno tests, note the results of bypassing the coolant that flows through the throttle body.... free 6 HP.

HP figures are very subjective. Just a rough number, unless you put it on a dyno. And even that's subjective. All comes down to how fast it is on the track. We all tried to add up the HP numbers for the various mods we did when we first started, but it was just a numbers game - meaningless.

I'd say assuming just a filter panel, you have added 25 HP + 125 HP for the nitrous. But it's the huge additional torque provided by the nitrous that is more important than the HP.

Then there's the matter of flywheel HP vs. rear wheel HP. Which trans do you have? Auto trans eats up more drivetrain HP than the manual trans. And, performance can be improved significantly with a higher numerical rear end ratio, and with the auto trans, a high stall torque converter.

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Old 03-31-2019, 05:48 AM
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Re: Where Iím at!?

Awesome info! Thank you! My car has the auto transmission and the 2.73 rear gears. The stall is still stock as well. Iíve thought about changing stall, adding shift kit and doing rear gears but Iím not sure whatís the best way to go. The car is such a good driver right now that I donít want to sacrifice that too much.
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Old 03-31-2019, 05:50 AM
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Re: Where Iím at!?

Oh and yes itís the K&N panel filter in the stock air box. That coolant bypass mod seems pretty simple. Thank you for that tip!
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Old 03-31-2019, 10:56 AM
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Re: Where Iím at!?

A set of 3.73 gears, 2500+ stall, longtubes and a tune should really wake it up. Then heads/cam and it will feel like a different car.
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Old 03-31-2019, 11:10 AM
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Re: Where Iím at!?

When i first bought my 1994 Formula,brand new in 1994 (was originally the T56 manual), I tried to keep track of the HP gains, by keeping records of track performance, correcting for altitude density. I bought all the available stuff, most of which showed very little, if any performance improvements. The biggest bang for the buck was a Callaway CAI and a Borla catback with the 3" mandrel bent intermediate pipe. That combo was good for a 3/10th's improvement in 1/4-mile time, which would correlate to a 25-30 HP gain.

The rest of the stuff did nothing I could measure - throttle body air foil, underdrive pulleys, adjustable fuel pressure regulator, 8mm wires, Hypertech Power Programmer, etc.. I never tried the 1.6 full roller rockers, and did the throttle body coolant bypass later, never attempting to measure the HP gains, because I had the dyno results for reference. The Hypertech did redeem itself with the addition of a 160-deg thermostat, and using the programmer to lower the radiator fan on/off temps. Probably good for 10 HP. Thing is that a much better approach is to have the PCM programmed. That alone can produce a 10-15 HP gain, by leaning out the PCM's excessively rich target A/F ratio in power enrichment (PE) mode = basically, WOT. And they can change the fan on/off temps for the 160-deg t;stat. But, good LT1 tuners are getting hard to find.

Also went for a 125 HP dry nitrous kit, using the NOS 5176-EO kit (was living in CA, needed the EO designation for emissions), Great improvement.

In your case, the 2.73 rear gears are holding you back. There was a "high performance rear axle" option (GU5) which included 3.23 rear gears, and a selectable 1st gear on the shifter. You could actually just trim some plastic under the gear indicator to allow access to 1st gear. Optimal performance for the 4L60E auto trans would be to install 3.73 gears. Do that first, before the stall. Save the stall until you go for a cam upgrade.

Good to see there are still LT1 enthusiasts out there..... we are a disappearing breed.
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Old 03-31-2019, 12:18 PM
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Re: Where Iím at!?

Bang for the buck = gears & stall.
Shift recovery will be much better with a proper converter.
If you're not looking for dragstrip performance then the stall can wait, otherwise I highly recommend no larger than a 10" converter.
Would seriously consider upgrading the rear end if you plan to do much drag racing (esp. with the N2O & sticky rubber) - I've broken three 7.5 rears 60'-ing slower than 1.85.
My car picked up a tenth & 1 mph with a very conservative (87 octane) tune. Switching to 93 octane with as much as 6 additional degrees of timing netted zero improvement in any increment on my (dozens of) 1/4 mile time slips. And yes, I do track density altitude. YMMV
The 1.6 rockers will be good for less than a tenth on your stock head/cam motor - hardly worth the effort IMHO. Hopefully you replaced the valve springs.
see here: Stamped Steel vs. Roller Rockers - Test Data Please! - Speed Talk
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Old 04-14-2019, 06:41 PM
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Re: Where Iím at!?

Iíve been busy! 3.73 Richmond 2-Series gears installed and throttle body coolant by-pass completed! Boy that sure feels different in a very good way!! Now that I have the K&N, SLP airfoil, Crane Cams 1.6 Roller Rockers, MagnaFlow Y-Pipe & MagnaFlow Catalytic Converter along with the MagnaFlow Cat-Back and a 125 HP Nitrous system itís time for a custome tune! I have also removed the plastic block that prevents being able to shift into first gear. I was thinking a Shift Kit, maybe Trans Go. I have the Competition Engineering Sub Frame connectors installed as well as the Eiback 1.3Ē lowering springs. Overall I am loving this car so much and enjoying each little step along the way!!!
It there a suggestion for a tune or ďchipĒ? I know I canít just unplug the chip and replace but Iím wondering what your suggestions might be and what might I see from it? Thank you ahead of time everyone!

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Old 04-27-2019, 09:21 AM
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Re: Where Iím at!?

Found a good reputable LT1 tuner only 30 miles from me in NewMarket Ontario at AGP Performance! The Camaro is going in to have a tune done for 93 Octane, the new 3.73 rear gears and for the Nitrous System. Pretty excited and absolutely loving the car! The best part is it looks bone stock from the outside. Now if the darned snow would finally go away for good I could enjoy driving it!!!
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Old 04-27-2019, 04:27 PM
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Re: Where Iím at!?

Is your nitrous system wet or dry? Generally, you tune the PCM to optimize power without the nitrous, then tune for the nitrous externally, with a timing retard box, window switch to limit low RPM system activation, and to cut nitrous before you hit the rev limiter. A wet system A/F ratio on nitrous would be done using the “jets” (various size flow orifices) in the nitrous and fuel lines, to correctly match the added fuel to the nitrous flow. Dry gets more involved, depending on the specific kit.
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