nattybohsbros

Hi, So i got a 1994 Trans am A4 Coupe 25th anniversery last week. it has ~51000 miles on it. I thought it was all stock besides the radio but after inspecting it a bit i saw that it had a K&N cold air intake and some sort of exhaust mod. I know its a Hooker Super Comp muffler but im not sure if its a whole cat-back system. What is the best way to tell if its just the muffler or the whole system. I was also curious if things like a computer chip upgrade are worth it, and if the throttle body booster thing for like $35 really works.
Sorry for being so ignorant to this kind of stuff!
Thanks

waltsfastz

iTrader: (4)

94 models wont have a PROM chip, and a tuner like hypertec is useless. You can send your PCM off for a retune, however with no mods it wont do you much good. The air foil doesnt do much either IMO, But someone else may chime in on that one. if you want to spend a few bucks go with a set of long tube headers. There are some Free mods you can do to get a few more ponys. as far as the exhaust most cat backs are 3 inch where the stock ones are 2 3/4(if I remember right) Not sure if that is OD or ID

hrcslam

First things first, Welcome to the forum!

Having an LT1 anything is like being the redheaded step child of SBC's. But having a 94-95 F-body LT1 is a little worse (not sure about the Corvette or B-Bodies, sorry) because the computer system is a hybrid of sorts that doesn't work with OBD1 OR OBD2 scanners.

So I recommend you first start off by getting the $55 ALDL cable for your car (it should be the 12 pin IIRC), then download a data logger/ scanner (Scan9495 is free). This will let you diagnose most of your electrically monitored or controlled sensors and devices on your engine and transmission. It can also scan and monitor your ABS too. This ability to data log will be a godsend in the future. Trust me. Optionally, on top of that, you can download Tuner Pro RT (free) and WinFlash from Tuner Cats ($20) and you can now tune your engine and trans.

Many of use will go this route, but have a mail order tune e-mailed to us for a good starting point post mods.

If your in the need for speed you can start with gears (and girdle), stall, sticky tires, and your basic bolt ons (headers, cat back, CAI, TB coolant bypass, pullies, tune). You will require a tune after all those are done.

Your car has low miles, but it's also 20 years old. If it hasn't been done yet I recommend a full tune up. And new valve springs while you're at it, it'll renew the high end power and if you get better than stock replacements you can rev higher (I'm using Howards Cams 98215 springs ~$110 and they work great!)! And you can easily do higher ratio roller rockers later.

Air foils and TB coolant bypasses have been dyno'd and each show about a 7 rwhp gain routinely. But 7 hp is also within the margin of error....

Don't touch that TB spacer, worthless IMO. On a small plenum carbed intake it has it's benefits, mostly because the carbed part, partially from the plenum part. On a EFI motor with an intake that can (and has) taken cars into the 9's with only porting, you certainly don't need it. If anything it'll actually reduce flow.

ThoR294

iTrader: (6)

my 94 hooked up to my uncle's snap on brick scanner with no issues? lol

hrcslam

Nice! That's rare, but it does happen. It still doesn't hold a candle to what Scan9495 can do with these cars though. And it costs much more. But, Scan9495 only works on these cars where that Snap On will scan many many cars.

In any case, I stand corrected. The 94-95 LT1 F-Bodies will work with only a few select scanners that are expensive and even many Chevy Dealers can't scan them....

myltwon

iTrader: (1)

95 was the hybrid year. 94-95 are the cheapest and easiest to tune.

bufmatmuslepants

iTrader: (3)

94 was OBD1 port and PCM, 95 was obd2 port and obd1 PCM. Obd1 is cheapest to tune as previously stated, and easiest it seems as many high hp 96-97 guys go back to obd1.

Get the whole chip/programmer/handheld thing out of your mind forever. Those are canned tunes "one tune fits all" programs, usually all they do is lean out your car from the rich "pass emissions" stock tunes, and rarely do they do anything positive on any application, and yet they cost the most since they advertise the most.
Get long tube headers, a 3" catback with a free flowing muffler like borla or hooker or magnaflow, stay away from the flowmaster for these cars as its known to be just as restrictive as stock although some say it sounds good, I prefer magnaflow for sound since its quiet at idle, roars at WOT, and flows the best. Shorty headers do almost nothing per dollar. You want to concentrate on $/hp, and long tube headers, a mail order tune, and a CAI are the best $/hp for these cars. Then you need to tune up your 20 year old car and replace the weak worn out stock valvesprings so you can shift reliably to 6300, new waterpump with a fitting tapped into the weep hole with a piece of tubing routed below the opti to save your opti should the waterpump ever fail. New plugs (ngk tr55 are good), wires, synthetic fluids everywhere (NOT ROYAL PURPLE), and some sticky tires and you will be on the right path. Then a 3000-3600 stall and an m6 Craigslist rear with 3.42 gears and you'll be mid 12s.
Don't forget about suspension though, your bushings and tie rod ends and balljoints are probably rotted, get some new rear LCAs with at least 1 end that can rotate with a rod end or spherical bushing, new eurathane motor and trans mounts (the stock mounts are probably sagging and new ones will ensure your long tubes don't hit the k member), and an lt4 knock module if you can find one to keep false knock retard at bay.

shbox

Whatever. 94-95 LT1s are OBD-I and work with any real OBD-I scanner. Please don't give out bad info.

nattybohsbros

Thanks for the feedback, so now a couple of follow on questions, when it comes to the long tube headers, is brand that big od a deal or the pacesetters ok, in addition would i have to get a " y pipe" along with the headers. Also, if i were to do the valve springs, would it be worth it to just do a cam at the same time becasue of labor costs and such?

slowpoke96z28

iTrader: (2)

Are you trying to stay emissions legal or no?

nattybohsbros

yes, preferably, but i could also maybe avoid that because of the age of the car. It will be my everyday driver at least for a while though

hrcslam

Really? Cause I have yet to see an OBD1 scanner with an OBD2 port.....

I know they are out there (like the Snap On ones), but I haven't seen one. And I've seen dealers go confused when trying to scan a 1995.

I stand corrected on the 1994. I thought since you couldn't use the paper clip, then the scanner also needed to be different than the standard OBD1 set up.

waltsfastz

iTrader: (4)

IMO do valve springs the same time as the cam.

shbox

Yes, really. Good scanners come with the right cables. Even the old Autoxray scanner that I have had since the 90s had the right cable available. This is nothing new to anyone that has a 95. A dealer that is confused needs to educate their people. An OBD-I capable scanner is needed to scan OBD-I. Nothing complicated, just use the right cable.

nattybohsbros

ok, another question. Ive read alot about 2.73 vs 3.23 gears and how either may be stock. So how do i tell which one i have without the original sales sticker and such.

hrcslam

The valve spring require you pull the valve covers, rockers, and spark plugs, plus having a way to blow air into the cylinder.

The cam requires the timing cover to come off, which would be the water pump and optispark and oil pan. Then you'll have to remove the radiator and condenser; so you'll have to evacuate the AC system too.

If you are doing higher ratio rockers or a cam swap the valve springs are a must.

But, if you are doing a tune up on an engine that is 20 years old and still has the original valve springs the valve springs are highly recommended. It's not a must, but definitely recommended.

Remember, an installed spring is a spring under pressure. And anything under pressure for 20 years is going to weaken.

Thanks for the clarification. Your knowledge, and website, has been a tremendous positive impact on the LTx community.

hrcslam

If your shifter has a selectable 1st gear you should also have the GU5 (3.23) RPO code. If not, then you should see the GU2 (2.73) RPO code.

Check out post #3 at this link.

TransAm1993

I have a 93 trans am and just bought about every bolt on for my car that I could get lol like the guys stated huge improvement with a set of long tube headers gears and I'd go with a yank 3600 stall ..when I did those all I can say is night n day from the factory setup then keep reading on this site find a way to get your baby tuned up then lookout !!!! A 160 degree thermostat is good too. Good luck its a lot of fun upgrading these cars !!!

nattybohsbros

ok, so it does have the 3.23 which is cool i guess. So obviously alot of this stuff boils down to cost. So is there a website or something you guys can suggest for the best price on these various parts? or maybe local mechanic can get the best deals

hrcslam

Google is your friend. There is no single website with the deals. Your best and most valuable method of modification is to learn your car. Then buy the parts that work with what you want.

One of the great things about the SBC is the interchangeability, but conversely, the shear amount of options can help you build a big pile of poo too.

Right now your biggest bang for the buck will be a stall, gears, headers, and tune. Throw in new valve springs that are a bit stronger and you can rev higher too.

Don't cheap out on the stall. There's a reason the guys running faster times with less power have the more expensive stall.

You can cheap out on headers, but get something stainless to prevent rust. Pacesetters are a popular option, but Speed Engineering has been making great progress into Pacesetters market share.

Motive/Richmond both make comparable strength gears; 3.73 seems to be the best balance for acceleration and DDing. But they are not as strong as stock. 3.42's can be had from GM which are pretty strong for a 7.5" gear, still better than 3.23's but may not be worth the effort. If you plan on exceeding 350whp on DR's or slicks anytime soon, I wouldn't worry about touching that stock rear at all. Not worth the investment beyond 350rwhp and sticky tires. Sometimes those rears will break with stock power on DR's. You have been warned. LOL.

There are a few mail order tuners left, but I don't remember who.