I own a 95 C4 and am looking for ideas for engine performance upgrades. Don't necessarily want to turn it into a race car but would like to get about 100 more ponys out of it and still be able to take long rides without problems. Not necessarily looking to put a Supercharger if I don't have to. Engine has 98K and runs pretty good but if rebuild will be suggested then I would like to get power out of engine and exhaust.
Thanks

 

100 HP gain naturally aspirated is a pretty tall order. Is the car auto or standard? If auto an aftermarket torque converter and steeper rear end gears would take advantage of the new cam and reworked heads. Check with Lloyd Elliot for head work and a custom cam:

http://elliottsportworks.com/

 

Adding 100hp to an LT1 isn't very hard at all but a chip and a throttle body isn't going to cut it. (Seeing as this is your first post I thought I would just throw that out there) The easiest and cheapest way is a 100 shot of nitrous. Some people aren't open to nitrous and that's ok. From there you're looking at a blower or, like Scott said, heads/cam + some exhaust work. Also like Scott said, if this is an auto car start with stall/gears to really take advantage of the power you already have, you may find this gives you the boost you're looking for.

Search the forum, there are more than a few threads on LT1 mods that work and mods that don't .

 

I agree with the above posts. The cam profile you would need would be rough for cruising. You could get the power you need with 5 psi of boost which is very conservative, and be very driveable.

I'd call EAS and start there. Otherwise, as stated, headers, cam, tune, exhaust, gears, stall converter if needed.

 

If this a A4 with the 2.59. IMO a gear change would give the biggest bang for the buck.

 

This is all you need for a performance boost; one emblem for each side of the engine bay. Guaranteed 50HP per each
badge added!

 

Thanks for the quick response, car is a six speed and from what I seem to of read, gear changes doesn't seem to be necessary but will investigate further. Will also look into nitrous option but years ago when I had friends adding HKS systems to their cars, I remember them saying eventually it causes engine problems so I was a bit skeptical.

 

The best thing you can do is call Lloyd Elliott.....

 

supercharger is the quickest way to 100hp gain plus the huge tq is everywhere not just way upstairs. You can leave your gearing alone
Youll spend about the same either way. As said 5-6 lbs wont hurt anything its a huge improvement.

 

Yup. I mistyped.... ECS is just one of many good companies. Find a company with lots of experience so you have minimal problems.

I have a ZF 6 speed with 4.10 (or whatever) gears and I really love them. I have 19" wheels though. It could actually use more gearing, as I have a pretty stout cam profile.

 

I agree a supercharger is the way to go. If I had to do it over again that's the way I would do it.

 

Buy an LS upgrade chip for your car.

 

I agree - obviously ! greg
Cost you about $10K to do it right but done right it's like a new car ! 100+ across the board and very reliable BUT lot of work and a lot of money !

 

If rebuild is an option 383 ported or aftermarket heads and cam with required tune. 4.10 would make 6th gears more useable.

 

 

Adding 100hp is a solid goal. Is there a particular reason you chose 100hp?
I have a supercharged C4 and a Supercharged IROCZ, and previously had a 95LT1 Z on a 125hp shot of Nitrous. Funny thing is, I had always wanted to do a supercharger and just didn't get there on some of the other cars I have owned. One is Prochraged and the other is a Vortech. Thing is, these are not for the faint of heart. I want to make a point about the Nitrous, it in itself will not hurt the engine if done right, and neither will the supercharger. Both (and while we are at it, this applies to a turbo as well) open the door for things to go wrong that can lead to a quick or immediate failure. The key is to do it RIGHT and to size things appropriately. You can't hit a stock LT1 with a 300hp shot of Nitrous no more than you can hit it with 20lbs of boost.

With that said, I didn't like nitrous. There are issues with legalities with "transporting" a nitrous bottle. In some states, without a permit, it is straight illegal. The added power isn't there across the board only when its turned on, and it is a bit scary to be honest. Even with a RPM switch, a fuel pressure switch, bottle warmer, and purge system it always felt like a hot girl that was crazy. I wanted to hit it, but long term effects scared me.

I love my superchargers, but the kits they sell are not the greatest out of the box, and to do it right you will need to spend some money on the fuel system, tuning, and other odds an ends. However, this option gives you a new feeling of power across the board. Any RPM, any gear, any load... the car will always feel stronger. Plus it makes a really cool sound. It does add new maintenance items, added potential of throwing belts, more stuff on the car, and a fairly involved installation.

H/C/I may be your best IMO for what you listed. Well proven combinations exist in the market. Installation won't be as lengthy as a supercharger, and it is not adding additional items that were not on the car. Just swapping them.

Now for my suggestions. First thing should always be to start with a car that has a clean bill of health. Is all the maintenance up to date? Do you have good plugs, wires, filters, etc? With an M6 car and you want it to be a bit stronger and faster. I would start with a 4.10 gear. No question. With the deep 6th gear, it won't affect mileage too much and add a performance shifter. This will make the car feel much more alive. Then do a set of Long Tube headers with high flow cats and a nice exhaust out the back. This will add performance, and you will notice it, but it won't be huge. Though, the new sound will completely change the experience. Then do some cheap stuff like a performance air filter and cutting the lid open. After all this, then take stock of where you want to go. The gear may be the only thing I would reconsider if you know you are going with a blower or H/C/I. Then I would stick with a 3.73. With what I mentioned, you won't add 100hp, but it will feel like a completely new monster and should give you the experience and feel you are looking for. Plus, It should all be able to be done under $3K.

 

Above is very clear and VERY good information. From experience is always best .

 

If you dont like the S./C route putting a bigger arm (crank) and a super good head will give you satisfaction. Sometimes that tq of the longer stroke is what most guys hoping their stock stroke H/C job will feel like and rarely does.
another 1/4 pr 3/8 inch makes a BIG difference. Then you dont have to use deep gears and a cam that shortens valvetrain life. Id never go back to a smaller engine again. Forget all that talk about "they like to rev"....whatever. To make any power they HAVE to, with the larger engine you dont. Less throttle, more grins.
Anything can rev theres good enoguh parts out today you dont have to worry about it. RPM kills motors and costs a lot

 

If you are rebuilding, I see no reason to not go the 383 route. Again, a lot of proven combinations on the market that have a lot of longevity.
The rest of that is pure crap. Over-revving an engine can kill it sure, but there is no reason a SBC can't spin 6500 RPMs and have a long healthy life. If the H/C/I and bottom end are all matched to do this. There is no problem.

If you think RPMs are not important, try building a 383 TPI and a 5.3LS. One will make more torque, the other will be faster, and both will last a very long time. Low RPM Torque monsters are not high performance engines. It's all about area under the torque curve, and to be able to produce it longer and into higher RPMs is better for performance applications.

By the way, I LOVE my TPI, always had. Love the low end grunt and strong punch they have. The downside is they fall off quick.

 

Think you misinterpreted the post. A lower rpm tq engine will outlast one that has to rpm for power every day of the week.