Eaglerulez

So I'm planning to hang on to my C5 corvette for quite a while and have been slowly modifying it to make it a better and better car.

Right now it's sitting at close to 98,000 miles and has the following mods:

CAI
X-Pipe
Exhaust
Tune
Z-51 Sway Bars
Z06 Shocks
Lowered on stock bolts
Michelin Pilot Super Sport Tires.
Hawk Brake Pads
Drilled/Slotted Rotors
Stainless Steel Brake Lines.

It's a 2004 A4 with 3.15 gears

The car handles great, is punchy, and as a whole is a blast to drive. But I'm trying to figure out what to do with it next.

I've always wanted coilovers, but at the moment the car is in a really good place handling-wise so I am not sure if money spent there is worth it at the moment.

I do want to add more power to the car, but I'm at the point where "cheap" power mods aren't really an option. My tune and CAI probably added about 15-25hp all together and though I could tell the car was faster, it wasn't a huge difference in performance.

I could add an intake manifold, some shorty headers, ported throttle body, etc. For about $3,000 including install but I'll still maybe net another 30hp.

I really like the idea of a supercharger but they're running about $7,000 with install and that just seems like a stupid amount of money to spend all at once on the car...at the same time it would completely change it and make it a beast.

Part of me likes the idea of changing from 3.15 gears to 3.73 and maybe beefing up my transmission along the way (because let's face it I'm not going to go over 100mph without getting arrested) but I've also heard going from 3.15 to 3.73 isn't a big enough jump.

I love the idea of getting heads and a cam for the car but it's an automatic which means me getting all sorts of other stuff to keep it driveable.

Anyways! What do you guys think. I'm in a strange place with this car. I want to keep making it better, but at close to 100,000 miles I know I'll need to make repairs somewhere down the line so I don't want to spend all of my money in one place. Likewise...I feel like I have to spend a few thousand dollars somewhere to get a moderate improvement in performance, but feel as if for a few grand more I could just get a supercharger and ease all performance concerns.

My overall goal with this car is to make it a DD that can spank 99% of what's on the road, will last me a long time, and as a whole will be reliable. I don't necessarily have a budget per say, as I plan to hang on to the car for a long time (so money invested in it is a plus as far as I am concerned) but knowing that it's an old car I don't want to drop lots of money on mods all at once and then not have enough money in reserve for repairs.

Any thoughts?

REDSEE5

Dont waste time with shorty headers. The stock manifolds flow almost exactly the same. Also, you already have the Ls6 intake manifold since it is a 04, so I wouldnt look at any other intake manifolds. Since you already have an xpipe, TSP sells LTs for around $500 shipped. Your best best would be LTs, gears, and a stall. With those mods you should have a VERY low 12 sec 1/4 time if you can get it to hook.

Also, going from a 3.15 to 3.73 WOULD be a huge jump, FYI. Upgrading the stock throttlebody is also going to be a waste of money until you start getting WAY up there in HP #s (500+) IMO.

Im in the same boat as you. 02 a4 with 98k on it. Getting ready to do LTs.

ApexerER

I am in the same place with my 03 Z but I only have 50k on mine. I have no plans on ever getting rid of it.....I have your mods intake, tune, headers, x pipe into stock Z mufflers. I have a tick master and LS7 clutch as well but you don't need to do that with an auto...I put 4:10 gears in mine and feel like that was one of the best mods out of everything I have done so you may really want to consider gear. I don't know what your RPM would be with an auto but mine is 2200 RPM at 70 MPH....Like you I have done all the "cheap" mods and I am wondering what to do next. I would love forced induction but like you said...dropping 7K all at once is why I don't have it now. I keep thinking about adding a cam, but I don't because I always have a supercharger in the back of my mind. This spring since I couldn't make up my mind, I did a radio upgrade and went with a Double Din from Double D mods. Very happy I did that so that is my mod for this year and I will just drive it for the summer. Next year I will probably ponder all the same questions....I may bite the bullet and upgrade the seats next spring....We will see....Good luck

Eaglerulez

Sorry forgot to mention that I am in CA so I can only do LS7 exhaust manifolds or B&B Shorties (which I have heard are good for 10hp despite being shorties). I like the B&B route only because I can keep my X-pipe and really like the sound of my C5 as is.

Eaglerulez

Yeah I actually like the idea of heads/cams but with me being an auto I keep hearing all of this talk about needing stall converters, etc to make it drive-able (and then on the flip side you hear people saying that stall converters make the car feel loose and sloppy). Once start to add up all of those costs you're looking at close to $7,000 anyways haha.

If I were to go with gears though I think that would absolutely eliminate going with a supercharger though. That would be too much torque for the car.

twizted91gt

Yes as stated please dont waste $$ on shortys. Do a set of longtubes the first time, you will be happy u did. Texas speed, XS power and others make affordable setups that make great power and are the same install cost as shortys will run you.
You do headers and then save your $$ for a cam package (~$1800) and you will be PLENTY happy with the results. Im the same bolt-ons as you with a HPA installed cam and im at 426rwhp. As you want my coupe beats a good amt of cars on the road.
If you have the $$ to spend id def recommend looking into calling Perforabuilt for one of their lvl2 4L60E trannys and one of their converters.
When i installed a lvl2 tranny and one of their billet 3200 stall TQ converters in my 02 WS6 i knocked just about a full second off my QTR mile times with those 2 mods alone. Well worth the investment.
Basically you have to decide if you wanna continue spending $$$ on the car and keep enjoying it or cut ties and start with something else.....

Cutlassmaster

Supercharge it and be done with it. Take it to A&A that way you know its tuned right. I paid about $4800 for my kit from there. Add about $400 in other upgrades and $500 for tune. Did work myself except the tune. Lasted 3 years and 13K miles before I had a piston issue. My new tunner parts guy said it was in the tune. About $12K later I'm rolling again with lots of upgrades.
I would say supercharge it but tune has to be right so that it will retain engine longevity.
Chris

corvet786c

If you know that you are going to keep your car for a long time, why not just get a procharger and be done with it. Its what I have and will be able to keep up with 98% of the cars on the road, and it fun too.

It all depends what your budget is and plans with the car. If there is a inkling of selling it for another newer vette than forget modding th C5, just saying.

wildazme

The cheapest and easiest route would be a nitrous kit, you can add anywhere from 50 to 100 hp instantly on the stock motor when you want it. It will give you the extra performance when you want.

dbgoodwin

the problem is, some of us put 13k miles on our car in a year!

Being that the OP is in California, my best advice for a first step would be to move out of California. If that isn't an option, you're going to be maxed out pretty quick with what you can do power wise without supercharging. If you go that route, just make sure the tune is spot on.

Riteaidkid84

Cam

Ducati Guy

Mine is stock. My feeling is that unless one is going to track the car there is no need for gobs of HP for street driving. simply no place to use it. And if you do the chances of getting in a heap of trouble are quite high.

I had a track only Ducati up until recently. And even in its street form it was waaaaay more than necessary for riding on the street. And on the track it's ability was well beyond mine. Unless one has the skills to match the power it is not necessary, and even be dangerous.

One of the thoughts in the high performance bike world was to put your $$$ into learning how to ride better. Not into mods.

DTA4

What changes would you need to make to put nitrous on stock car?

Rob 02

I purchased my car needing an engine rebuild. I installed LS6 cam and heads. I had the heads ported and polished mildly by my local shop. The heads were decked slightly .007" and I went with a slightly thinner head gasket for a bit more compression and better quench. Then I went wit the flip tie mod and mail order tune. I haven't had it dyno'ed yet
but I am guessing that the FWHP is around 450. I am not a racer either but enjoy a little extra power.

I like low and mid range torque for around town. It seems like a lot of mods are only felt at RPM's above 4,500-5,000 rpm which is great for racing but not that beneficial for spirited daily driving. Some of the bigger cams will cost a lot in low end torque. That is when a higher stall is most beneficial. Lower gears may be nice but not necessary if you are going to supercharge in the future.

I guess it all depends on what your goals are. If you just want a better driving experience then stereo upgrades may be the answer.

Scylla

I'm also in Cali and I went with a FIPK K&N Intake, the power increase was immediately noticeable and the whole system feels much less restricted with the intake. I'd recommend that as an immediate upgrade.

I would also strongly suggest you get Z06 Sway Bars and Leaf Springs to go with your shocks. It makes a huge difference, not just in handling, but even acceleration since the rear leaf is way way higher in spring rate. Stock springs settings are a gooshy mess by comparison and designed to prevent people from getting into trouble.

If you want to supercharge, I don't have a lot of advice there. It's up to you, I personally prefer NA engines. You can also consider the best way to build a relationship with your car: performance driving lessons and posting times at one of your local tracks.

fuggles

I agree with those who've said gearing. With a 3:73 you'll get 20% more acceleration. It takes a lot of HP to get 20% acceleration. And if you are not tracking you wouldn't care that the top end hasn't changed.

Rob 02

I am assuming the 20% or 18.5% increase would only hurt fuel economy by that much as well. It shouldn't hurt reliability at all, in fact should be easier on the drive-line (except CV shafts). It should feel like a 70-80 Hp gain.

If you know how to swap the cam and heads you could get the same results for around $1000. Then do the rear swap and you have created a monster.

bonzo

about 60 days ago I had my 04 A4 vert in the shop just looking for a bit more punch - the feeling I used to get when I first bought the her more than 8 years ago. I did PFadt LT Y headers with high flow cats, X Pipe PFadt CAI and I changed the gears from 2:73 to 3:42. I had the run flats changed out to Nito Invos. Then she was tuned. I guess I was looking for more as I didn't see the power and excitement I was looking for. The gear change was not as dramatic as I read it would be. My gain in HP before the work which was the stock car with a tune was 305. After all of the work and nearly 7K was a whopping 320 ( I thought i would be near 400)so I'm not sure where all of you guys are picking up all of these extra ponies or if my tune guy just isn't there yet. So I guess what i'm saying is I think I would like to have the 7K back in my bank. Don't get me wrong she's a killer but not a 400HP killer. Next step is to get the Cat back exhaust change. Shes my daily driver I don't track here just for the record!!

Rob 02

First of all the rear gear swap doesn't add HP. In fact the HP will probably report lower on the dyno. What it will do is make you accelerate quicker as if you had more HP.

Headers don't add much HP as the stock exhaust breathes well enough for a Z06. Exhaust mods are only good for about 12HP on a stock engine if that. Your CIA and tune are probably where you saw your HP gain.

As I mentioned, I installed Z06 cam and heads with some mild mods to the heads. I did the install myself during my rebuild at a cost of around $1000 (I replacing parts anyway so that is only about $400 0ver what I was going to spend anyway). $500 eBay headers work as good as anything to be quite honest. My flip tie intake mod with K&N filter and pre-filter material costed about $50. You don't have to spend a lot to gain 100HP if you can do the work.

That being said it sounds like you have a good platform to start making HP by adding a cam and heads.

Roddy13

Sounds like its tastefully modded so far. Keep taking your time with it and enjoy it. 98,000 is nothing for these cars.

Next on your list I would add a set of headers... either XS power or Texas Speed... both brands are under $1000. Then Gears..3.42 or 3.73.

Take it from there.