Let me start by saying I was always a Ford guy that was awakened by a 95 Z I bought last year.Was a 95 M6 with 100k that I stole from a guy transferring to Hawaii.It had several owners but was kept clean and ran like a wildcat.I have no idea what internal mods were made.It had immediate throttle response.Had a CAI and underdrive pulleys and a larger than stock exhaust.I upgraded the ignition and opti also.I sold it due to 2nd left foot surgery-goodbye clutch.Just purchased a Grandma owned 94 A4 63k miles.The throttle response seems to lag.When it kicks in it has breakaway power as they do in stock form.I missed a great deal on a NIB 58 mm tb last week.My question is where would the pros start.I do want this to be a slightly modded daily driver.I am also a Grampa in my 50's.I know the 6 speed 1-2 ratios and bigger rear gear accounted for power differences.I want to start with basics.At 63k on a 17 year old car I imagine the plugs,wires and opti internals are done.What brand plugs work best.Is there a true performance difference in plug wires.Is MSD the best ignition.What CAI performs best.Is a 52mm or 58mm tb best for daily use.I forgot to mention I only got 14 mpg on my first full tank.1/3 of miles were interstate and 1/3 in town and 1/3 leadfooting it.That is why I assume it needs a full tune up.Another question is after I replaced the 180 with a 160 t-stat it seems to run hotter.Coolant full and radiator 1 year old.It was a Duralast t-stat.I assume they are dual function t-stats since thats what they listed for the LT1.Thanks for taking the time to read this long post.

 

Are you sure you used the correct thermostat? Did you get the air out after replacing it? I would replace the plugs and maybe wires, depending on how they look. Sometimes the fuel filter is neglected and might be a good idea to replace it.

 

Ignition "upgrades" are wasted money for you. I run stock ignition on my car, tried a few ignition boxes and found either problems or no gain. Don't assume the old stuff is always still tried and true, don't assume that just because someone sells an easy addon it is anything but a problem.

Far as the TB, putting a larger one on requires either a shift kit or reprogramming with the A4 tranny as one of the things the computer takes into account is the throttle position when determining line pressure. With a bigger TB the engine is getting more air at a given throttle position and therefore making more power and needs more line pressure. For a stock engine I might consider a rebored stock 52mm, all the aftermarket TBs have little hassles only worth dealing with if you need a 58mm.
IMO a 52mm with increase throttle response more than outright power, but it sounds like that is something you want.
Your other car had pullies but I would NOT bother with them as they do a better job on cars with belt driven waterpumps, since our pump is not belt driven there is much less opportunity for gain.


Far as mods is visual inspection a concern?

 

How hot is the car running? If you replaced the Tstat without reprogramming the fan speeds it should stay pretty close to the stock temperature.

 

Once you get it all up and running correctly install a 3200 edge racing or yank 3200ss stall along with some rear gears and you will have a low 13 sec car. A mail order tune will be needed also. The best bang for the buck mod you can do on a A4 car is the stall; that is if nitrous is out of the question.

 

Are you sure they gave you the right thermostat? Some of the monkeys working at the box autopart stores aren't very smart when it comes to some parts.

Your thermostat should have two 'discs' on it- you described as being two stage, just want to make sure. A while back I went in for one and the one their computer listed for it was a simple SBC thermostat...however a LT1 thermostat should look like this-


As far as performance mods go, it is as deep as your wallet can go. A simple bolt-on car can easily get low 13's in the 1/4- start with cam/heads, suspension, torque converter and you are solid mid 12's.

As far as 14mpg- I would say that's about right with the combination of driving. These cars can get decent mpg but when you put your foot in it they are thirsty too.

 

For spark plugs the stock AC Delco's are nice but very expensive. A good cheap alternative are the NGK TR55's. Only 1.50$ each or so compared to 10$ a piece.

Spark plug wires I have used a couple brands... Taylor Spiro-pro 8mm, currently have the MSD 8.5mm Super-conductors, they both work well. Honestly I don't think there is much of a difference in performance.. The thicker wires do reqquire some modifying of the stock spark plug wire brackets to fit so you might wanna buy the 8mm wires if you're gonna run them in the stock locations.

For a CAI, SLP, Moroso, K&N... once again they all work the same way so just get whichever is readily available or just keep your eyes open for one in the for sale section you will probably get a good deal.

Good luck with the new ride

 

if it is just running a tad bit warmer you could try running some water wetter in it with your coolant will cool it off a lil bit as far as the thermostat i think i would stay with the 180 i think oil will boil water out of it at 180 or 82 degrees i had the same problem with a 96 gt mustang couldnt figure out why it was running hot over 45 it was fine under it would constantly get hotter due to sh!ty air flow if it is 17 yrs old think i would have the radiator takin out and givin a acid bath even with the low miles it might have calcium in it if somebody used tap water to fill it up always use bottled water dont know if this helps but figured i would give you my 2 cents worth