1991 L98 Auto. I can do some moderate work. Anything I can complete in an apartment garage without getting the landlord after me...

 

Well then it will get expensive quick if you got to pay for stuff to get done. Not as sure on the l98 but I know on my LT1 every mod benefits best when done with several others so it's hard to do just a few small things. A 300 cam shaft gets expensive when it means you need new valve springs, roller rockers, a tune, especially if you pay to have all that done.

 

Maybe you could give me a break guy. I just established this account like a day or two ago and am still in the process of obtaining the car so I thought it better to wait until it's in my possession to update my profile.

 

Astute observation. I'm not driving it yet, however, will probably take a couple of weeks before I can go pick it up from Cali.

 

My main intended purpose is going out for recreational street driving on the weekends, this will be essentially replacing my motorcycle. I live near Hill Country in TX, so there are some nice twisty routes I'd like to run the car down. I'd like to increase the fun factor, so I thought about intake and exhaust because those have immediate audible feedback most of the time.

 

Cam. You won't get more hp/$ from any other N/A mod than a cam.

Hence, "If you can do the work yourself". But the same can be said of:
*Exhaust
*gears
*converter
*Shift kit
Don't need roller rockers to do a cam.
You MAY not need a tune, or spring, depending on the cam...especially w/a 4500 RPM intake. Finally, since it's a roller cam...could buy one used for ~150 and really crank up the BFTB.

 

I would suggest exhaust first. Not too expensive and the extra sound will add to the driving experience. Then cam, rear gear, trans shift kit maybe, etc. later as your funds come available.

Welcome to the forum!

 

For 2 grand budget make sure it is up on all maintenance, brakes, plugs, wires, maybe tires (not many used cars come with new tires and these sizes ain't cheap) basics first. Then drive for a while unless you are coming from some other performance car the vette is gonna feel pretty fast. Just my 2 cents.

 

I'm still waiting to hear what uses the OP has in mind for the car, and what aspect(s) of performance he would like to upgrade.

 

Regardless of who you are, when I buy your used car, I go by the simple phrase of "It flows, it goes". Every liquid goes so I have a baseline. After that, you have your regular maintenance items, plugs, wires, cap, rotor and other things to consider before you mod it. If you don't, you could possibly regret it. Ask me how I know.

I don't know how much is left after that but if you really want to do something, it will be headers and intake. A good set of ceramic coated headers is a little north of $1000. After that, you are looking for say a used MiniRam or Superram to open up the torque curve which is likely to be north of $1000. $2000 isn't that much so consider carefully. I would increase the budget to really do something meaningful or probably not do it at all since it won't be really worth it, IMO. I don't think you really need an exhaust until you start to push more than you are doing. IOW, I don't think the cat back is your choke point. More likely the headers and intake but as I have said before, good stuff isn't cheap because it doesn't have to be and/or can't be. Cheap stuff isn't going to be good since it is probably going to be wanting in some way or another.

 

Sorry just irritating to have to try to guess what vehicle and location with new members. Even those with cars. Not sure what the secrecy is about myself.

 

I can get behind that idea. Off roading for the vette enthusiast.

 

I agree completely with aklim regarding his suggestions:

Regardless of who you are, when I buy your used car, I go by the simple phrase of "It flows, it goes". Every liquid goes so I have a baseline. After that, you have your regular maintenance items, plugs, wires, cap, rotor and other things to consider before you mod it. If you don't, you could possibly regret it. Ask me how I know.

So after you do all of that, drive it a while, save your money, and then make modifications. My 90 L98 has over $4,000 in the engine alone after parts and machine work. So it’s not cheap to build them and I do everything except machine work myself.

Just enjoy driving a C4 Corvette.

 

A 1991 A4, probably start with exhaust and TCC is the best choice.

But I agree with the sentiment that you should drive the car 6 mos minimum before you do anything to it if you dont have it in possession today. Your opinions will change by then.

Any 91 L98 A4 needs a new TCC, preferably 2000-2200rpm stall.

Any L98 engine responds pretty well to headers and exhaust. I'd do those before I made long term plans.

I've been in an apartment and they wouldn't let me do extensive mods with the car on jackstands for any length of time, so forget cam changes or things like that for now. Simple stuff that you can do quickly is the best bet.

 

Headers, I get. Is the cat back portion that bad where there are benefits when he is stock? Do you think that power wise, it makes the difference for a stock system?

 

Tests and 1/4mi showed in the past that you'd get 10hp or so from catback only, so yes. 10-15 from headers. ~30 hp total if you lose the main cat or replace it with a modern one. L98 is restrictive everywhere.

 

IDK why, but I originally assumed that the OP's car was an LT1. It's an L98.


YES. It's weird that you advised against exhaust above. What was that? A WAG? After 30 years, we know that the exhaust on L98 is not good, and that it IS a restriction.

I built a dual 2.5" for my 'Vette Kart, engine is box-stock, except for no air filter, 125k, not-taken-care-of-miles, and junkyard injectors (from a Buick 3800). It put down 240 RWHP. What do most box-stock L98's put down? ~200-210 RWHP. So it stands to reason that my "manifolds back" exhaust picked up about 30 RWHP. That is a lot of power for one part.

I agree with others, and I feel that on an L98 headers and exhaust are probably the BEST place to start....but they are NOT the best BFTB. Headerrs are $500-$1200 and exhaust is about the same, unless you build it yourself...then it's ~$40. Anyway, while not the best single mod for hp/$ is the cam. A cam could get you about the same gain as the exhaust that I did, but do it for less money. Would the cam ONLY make the car as fun to drive as headers/exhaust? I don't think so, but it would net similar power for much less money.

 

Well, the OP ran into trouble making additional posts, so he wasn't able to answer my questions about the intended use of the car. In a PM, he told me: "In short, weekend fun drives. Twisty roads in TX hill country."

If it were me starting with a dead-stock 91, on the power end I'd start with the exhaust upgrades Tom is recommending and a short-runner intake of some sort. The latter would add 1000rpm of flexible engine usage and additional power, while still not requiring internal "surgery" on the engine. Depending on the current rear axle ratio, that might need to be upgraded if it's a 2.59 to at least a 3.07 or maybe even a 3.45 gear set.

I'd go through the whole suspension and check all bushings. I'd buy the Banski rear camber rods (strut rods) and swap those in so I'd have stable camber settings. I'd replace the shocks, assuming the original Bilsteins are still on the car: my rec these days is Ridetech HQs. Assuming the car isn't already a Z51 version, I'd consider looking for a set of Challenge springs to slightly lower the car and increase the spring rates. Finally, I'd flush the brake system and put good fluid (like Motul 600) in it, and upgrade the pads to something like Power Stop z26 front and rear. If the front brakes aren't the larger J55 setup, that would actually be a useful upgrade for those Hill country roads (I remember those...). But the best bang for the buck regarding handling/grip is TIRES. If the car isn't going to be driven in freezing temps, then I suggest the Contental ExtremeContact Sport because it has excellent dry grip, class-leading wet grip, and it's reasonably priced. The car should have 17x9.5 wheels front and rear, so the 275/40/17 stock tire size is the best idea.

 

So you think if all he slaps on the stock car is a cat back, it will net 30 HP? That sounds a bit much although Borla claims a 41% increase in flow but not sure how that translates to HP or what engine they used. For his budget, I'd get a better (used) intake and headers. Now if you can get 30HP with just a cat back on a stock system, I'd be in.

 

One thing that bugs me is when people buy a Corvette for the first time in their lives and immediately The Corvette has to get modified as it is not powerful enough for whomever bought it. My C3 with it's 427 would be lethal in the hands of an inexperienced driver assuming they could even drive a manual transmission. If you have previous experience with Corvettes then you are more knowledgeable and familiar with the habits and routines of the Corvette then you won't have problems.

I have never heard that term you use there Aklim, If It Flows, IT Goes! I like that as I do the exact same thing (except on high mileage automatics). I need to baseline everything so I know what I am dealing with. I frequently even go so far as changing the brakes to pads I like and replace the rotors if needed to. I will tune the engine and ensure everything is working and then just enjoy the Corvette.

When a person buys a Corvette for the first time they should drive it for at least 6 months before making any changes to the engine or suspension. "Learn the Corvette" is what I tell them as it is different that anything you have had before. Learn the quirks and positive items about the Corvette and make a list of what you think needs to be repaired or modified.

I try not to make multiple changes at a time but I verify if they help or hurt my performance. I have been able to increase the mileage of our Pick Up by installing an MSD Coil pack. I have measured the mileage before and after and the GTECH did the performance verification.

My MSD ignition was a big improvement over the K66 Transistorized Ignition performance. I even had my K66 system re-built along with the distributor for it. The spark from the MSD is light years better and louder than the K66 was able to deliver.

On my C3 when I made changes in the carburetor I would take it to a empty parking lot and verify whether it was a good change or not.

On the C4 when I changed the exhaust I could not see putting a High Flow catalytic converter on a Corvette with standard exhaust system. There is no reason to install performance parts in the middle of factory restrictions like the original exhaust. The almost 14 hp was the difference measured after the new system was installed.

A Strong ignition system is always a plus in my humble opinion. I have seen the results in my cars over the decades. My First engine I installed a stronger ignition system was a Ford that I had while In college. It had the 390 c.i.engine and was not great at getting good mileage. I put a stronger ignition system on it and the mileage jumped and the plugs foiling slowed down. Then I switched to a different carburetor and the mileage went up again. By the time I was done I was getting 21 mpg versus the 14-15 it got before. Did not have the GTECH back then but I am sure it would support my work.