Just bought a 2003 C5 drop top with 7000 miles on it. About 500 miles per year. The oil was changed yearly with synthetic but no receipt that reflects trans fluid change. Did it come with synthetic in the trans and is it a good idea to have it changed out at this time? Also plan on changing out cat back exhaust and I can p/u a Z06 exhaust for $300 shipped. Does this make sense if I am looking for better sound and a few horses? Thanks for your input.

 

 

A bit louder, not much.
No cat back is going to give you any discernible power increase. Buy it for the sound, but listen to some first (including if you/they have the same manifolds and motor). Some are disappointed with the Ti change alone.

 

Also, if doing a bypass, just get it done on your existing system IMO.

 

LOL!! Owning a 98 C5 Coupe,,, NOTHING depressed me more than the pathetic looking and sounding stock Cadillac looking exhaust tips.

I purchased a New 02 ZO6 and LOVED the sound and look of the ZO6 Ti system. SO,,,,,,,,,, I purchased a used ZO6 Ti system to install on the 98.

Some facts on the Ti systems.

There basically straight through mufflers with a stainless steel wool baffle inside. They weigh 26 pounds LESS than the stock C5 exhaust, They will NOT rust or corrode. They flow 100% better,

HOWEVER,,,,,,, installing them on your STOCK C5 will NOT make it sound just like a C5 ZO6! "FACT!" YES,, It will sound a LOT better at WOT . Idle sound is only a little better. Ti Mufflers will NOT have any DRONE. They will a a few HP on a stock C5 but nothing to write home about. On the other hand, they have been known to support Cars running 500 Hp without any excessive back pressure issues.

For $300, That's a SCREAMING DEAL! Get them. If you don't like them, you can ALWAYS re sell them for no loss. Hell, If you were close, I would give you $300 for them. LOL!

I have some pictures of Ti CAT backs removed from my 02 Z if you provide an e-mail address to send them to.

Bill

 

Oh,, I forgot,, They are a 100% bolt in without any issue system!

 

 

Will be fun follow

 

the stock trans fluid is DEX III (not a synthetic) I have read many articles that suggest against using a synthetic in the A4 but no clear proof

 

the z06 exhaust is pretty freaking quiet to me, it was one of the first things to go on my car... about the only thing thay have going for them over a quality aftermarket exhaust is their weight since they are titanium... aftermarket beats it in every other regard in my opinion... they do sound better if your car is heavily modded and they are bypassed but the tips still look too small to me, just depends on you and what you want

 

Firstoff you want to change both the tranny & diff fluid, if you have the ability to get the car up on blocks/ramps & enough clearance to get underneath on a creeper this is a fairly easy job you can do @ home yourself. I have done myself 2x since owning my C5Z over last 5 years & will be doing it a 3rd time before putting away for winter storage. When the fluid is only moderately worn - say 10-15k+ on it over 2 years driving the difference in shift feel & how the power is put down is actually immediately noticeable. W/ 15k on my fluids the diff came out black....it goes in CLEAR/whitish opaque & the tranny fluid goes in bright pinkish/red comes out dark crimson/burgandy. I highly recommend Amsoil fluids for these 2 particular swaps. The tranny stuff is Amsoil "torque drive" synthetic heavy duty AUTOMATIC (yes - you use auto fluid in your manual) - if you have an auto tranny (hope you don't) then this doesn't apply, use dexron auto fluid. For the diff Amsoil 75w90 "severe gear" synthetic fluid.

$300 is a GREAT deal on a good condition Z06 exhaust - it is a titanium piece, very very light & high quality. Not much 'louder" @ idle than reg C5, but does open up more so in the higher RPM's & FWIW I have a fairly heavily modified C5Z (headers/cam/intake/TB etc.) & chose not to touch the stock axleback because of the Ti "cool factor", lightweight, & the fact that @ idle/cruise is still civil & not annoying but @ WOT & gear changes it really screams & sounds to me like a cross between a Nascar & a smaller displacement euro V8, much more exotic & "polished" exhaust note than if I were to say keep everything else the same & have borla stingers or billy boat or corsa etc. - OBNOXIOUS

If you'd like I could send you a text w/ a clip of my setup just PM me.

I see another poster did exact opposite swapping axleback first - to each his own, but there is no debate, especially w/ the "corvette tax", the worst bang for the buck "performance" mod by far is an axleback on a vette........one scenario where I could see me getting an axleback on a Z06 (C5 or C6) is if I bought one that already had headers installed...but to shell out $1500-$2000 for headers/X pipe AND another $500-$1000 for a useless droning axleback didn't make alot of sense to me.

Lastly- I would also mention I have pretty much decided on not changing out stock Ti axleback unless it gets a whole in the muffler or whatever but when/if I want more sound I'm going w/ cutouts no doubt - you CAN gain a power bump w/ those, & in terms of pure shock/wow factor they're tough to beat, & when you want it quiet you press a button.....

 

I agree with Vetteman Jack about changing all the fluids; not just the oil/filter.
Can't say for sure what is currently in your transmission since nothing indicates whether or not it has ever been changed. It came with Dexron III, but GM quit licensing it around 2005. Dexron VI is GM's newest licensed trans fluid and is approved by GM for "backwards use" (or some other term), meaning you can use it in vehicles manufactured prior to the intro od Dex VI. Dex VI is a synthetic fluid and Dex III was regular petroleum based. Many stores still carry Dex III; also I believe Dex-Mercon is compatible with, and comparable to, Dex III.
That being said, many C5 owners like to use a synthetic such as Dex VI, Redline, Amsoil or other comparable trans fluid for the ability to protect the trans in higher heat situations.
I would suggest changing your trans filter, too, when you change the fluid.
For the differential, the factory replacement is Drexon LS Gear Oil 75W-90 (GM 88862624) . Mobil 1 also offers Mobil 1 Synthetic Gear Lube LS 75W-90 which according to Mobil's sales pitch "contains special friction modifiers designed for limited slip-type differentials. In most applications, the addition of special LS (limited slip) additives is not required. For axles requiring the highest level of limited-slip performance, OEM specific LS additives can be added to this fluid." Whew!
Here again, Redline, and Amsoil also offer very good differential fluids. With any fluid you use, ensure it has the Limited Slip additive, or get it and add to the diff when you are changing fluid. If you hear a chattering sound when turning corners, that typically is a sign you have too little LS additive. Also, I guess other members are using the old figure 8 action to thoroughly spread the fluid over all gears and the LS clutch pack. (4-5 times each direction should take care of it).
Good luck with your fluid changes. Please let us know if you have any questions on this since the trans/diff drain and fill procedures are different from most other vehicles.

 

Change the fluids and go drive the crap out of that thing. Poor car. These were meant to be driven, not sit in a garage.

 

Route 99 is correct on 2 pts I missed - #1 if you DON'T use redline or Amsoil that have adequate appropriate friction modifier included (not sold on the Mobil1 being in this category) then you HAVE to add it yourself when you do the swap & IMO I would only use the stuff in a tube you get from GM dealers. I forgot to mention - in my '04 A4 GTO I swapped the diff fluid w/ Mobil1 & was starting to get chatter bucking in tight low speed maneuvers - almost felt like a fresh cam LOL! Did a little research & added the tube of FM & the problem immediately went away.

Point #2 - he's also correct about the "figure" 8 break in after swapping fluid - basically just driver around in multiple circles changing directions in a big parking lot - then when you're finished do a couple donuts & a medium sized burnout to ensure everything is working properly (per corvette manual)

 

C5Dobie is correct - $300 is a very good price for the Ti exhaust. Idle sound on it doesn't do too much for me (I'm old, my hearing is gone, and I like the noise ), but when really going through the gears, the Ti exhaust has a great sound! And, if you want more volume, go with cutouts as he suggested. As Dobie said, it is a great way to have quiet when you want and volume when you want. I get some of that with my Billy Boat PRTs - nice, strong sound at start up and idle, definite volume when getting on the gas, yet a comfortable volume and no drone when cruising. But these are definitely going to be louder than the Ti exhaust.

FreeC5inAZ is also correct. A C5 in my lifetime will not be an investment purchase. It is, however, a great car to drive and to mod, race or show if those things are in your agenda. But Drive, Drive, Drive it!!
Many members on here have 200,000+ miles and of course there is the notable C5 in the NCM with 700,000+ miles so obviously the C5 is like the lil ole Energizer bunny and will keep on going. Have fun with it!!

 

Just my personal opinion, but changing ALL fluids on a newly purchased pre-owned car is cheap piece of mind. Also gives you a known basepoint to start keeping track of your maintenance. Like I said, just my opinion. Regarding exhausts, I like performance cars to sound like a performance car. The stock C5 exhaust, including the Z06 exhaust is too quiet for my liking. Lots of quality options out there, listen to them all, get opinions. I run B&B Bullets, not everyones cup of tea but you can't beat them for raw sound winding through the gears with your foot heavy on the go pedal (they do have some drone at lower R's though). Good luck!

 

$300 for tis is a great buy. They will be quiet with factory manifolds. You can always swap down the road (you'll get your money back easy) if you want more volume...better yet add some headers! Congrats on the new ride!

 

100% agreed with changing all the fluids. I bought a low mile garage queen zo6 and the first thing I did was oil, coolant, ps fluid, diff, and trans fluid. I plan on doing them all frequently so the easy to use pump for trans/diff is worth the cheap up front cost.

Didn't read every word so forgive me if this has been said already, but look into headers and/or high flow cats if you want more power and a better exhaust sound. I have stock z06 catback but headers, xpipe with high flow cats and I wouldn't want it any louder. The sound is great too.