New c3 owner performance questions
Thread Starter
Heel & Toe
Joined: Jul 2017
Posts: 20
Likes: 0
I bought a C3 and this is my first entry into the Corvette world. Unfortunately I have one of the L-82 engines tuned down for emissions reasons and I'm not fully satisfied with the power. It came with a weiand 142 which is also the first forced induction engine I've ever owned. The previous owner didn't really know much about it and told me to the best of his knowledge everything is stock. I honestly wouldn't be able to tell the difference in stock and aftermarket so I come to you for help. from what I've read a good free-flowing exhaust/headers is good for around 25 hp. but with my "stock" bottom End will I be able to handle that along with the supercharger at five psi without throwing a rod. I also looked into Vortech heads but I don't want to raise the compression ratio with the blower on there. can anyone point me in the right direction budget being roughly 3000
Last edited by rickiedh; Aug 11, 2017 at 03:45 PM.
Le Mans Master
Joined: Mar 2001
Posts: 5,738
Likes: 644
From: Lincoln, CA
My thoughts,
Headers with a nice exhaust are worth it. You are just freeing up a restriction that will allow the spent exhaust to get out of the combustion chamber better with allows for a cleaner intake charge.
Also in the picture of the exhaust the bracket above looks pretty bad. Did you go over the frame and bird cage for rust?
Without knowing how the internals are built check your timing and make sure you don't get any detonation. I always use Menthol injection on my Supercharger builds.
Headers with a nice exhaust are worth it. You are just freeing up a restriction that will allow the spent exhaust to get out of the combustion chamber better with allows for a cleaner intake charge.
Also in the picture of the exhaust the bracket above looks pretty bad. Did you go over the frame and bird cage for rust?
Without knowing how the internals are built check your timing and make sure you don't get any detonation. I always use Menthol injection on my Supercharger builds.
Drifting
Joined: Oct 2005
Posts: 1,615
Likes: 150
From: Forth Worth TX
Can you return it?
Quite honestly, it looks like you've made a mistake. I don't see how spending more money on it will make it any better.
You should have posted here before buying it.
Quite honestly, it looks like you've made a mistake. I don't see how spending more money on it will make it any better.
You should have posted here before buying it.
Last edited by Revi; Aug 11, 2017 at 09:18 PM.
Drifting
Joined: Jul 2011
Posts: 1,697
Likes: 139
From: Syracuse NY
A blower on a stock motor? Sounds like the previous owner had more money than brains and just wanted something that looked cool. I could MAYBE guess its a sleeper, but that stock exhaust is a dead give away. Judging by the pristine condition of the supercharger and the nasty condition of your bottom side, Im sure the previous owner just wanted to show boat. As others have stated, start with a set of headers. If you go past that...just go full tilt and add a cam and heads. You can do that for under 3K if you do the work yourself. Dont get discouraged. You have the makings for a very stout engine there.
Instructor
Joined: Sep 2011
Posts: 145
Likes: 22
From: San Francisco CA
Yeah why not? Have you gone through the ignition and fuel system to get it tuned right and up to snuff? A bigger exhaust will really help-though you might have to fiddle with the fueling a bit with the addition of a free flow exhaust.
Water meth injection seems like a good idea and also ought to allow you to push the tune for more power while adding some insurance against detonation.
Cooling system too-get a 190 thermostat in there. Looks like some of the foam seals for the rad might be missing.
Someone spent some money on this thing at one time-I think that sort of period speed equipment is cool. Clear up the deferred maintenance issues and always check the age of the tires-lots look good and are very old.
You might also look into the rear gearing and see what you have
Water meth injection seems like a good idea and also ought to allow you to push the tune for more power while adding some insurance against detonation.
Cooling system too-get a 190 thermostat in there. Looks like some of the foam seals for the rad might be missing.
Someone spent some money on this thing at one time-I think that sort of period speed equipment is cool. Clear up the deferred maintenance issues and always check the age of the tires-lots look good and are very old.
You might also look into the rear gearing and see what you have
Last edited by Sunracer; Aug 11, 2017 at 10:38 PM.
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Instructor
Joined: Sep 2011
Posts: 145
Likes: 22
From: San Francisco CA
Here's something else to look at 
http://documents.holley.com/199r10244-1.pdf
Manual for install of your system.
http://documents.holley.com/199r10244-1.pdf
Manual for install of your system.
Drifting
Joined: Jun 2012
Posts: 1,990
Likes: 183
From: Port St. Lucie Fl
If youre not familiar with a supercharged setup, might be best to take it to someone that knows what they are doing or remove it. A lean condition or wrong timing under boost could blow a hole in the pistons, bend a rod or throw it through the block.
Thread Starter
Heel & Toe
Joined: Jul 2017
Posts: 20
Likes: 0
I gave 5500 for it, you can tell me if I got hurt or not. But I really wanted a 4 speed and a black paint job,this was it. Also I checked the bird cage as best I could on site and while it's not perfect by any means it wasn't flaking and full of holes
Last edited by rickiedh; Aug 12, 2017 at 03:15 AM.
Pro
Joined: Jun 2016
Posts: 567
Likes: 82
From: Auckland
Asumining the frame checks out ok, you may want to look at the bushes and any other rubber part as well.
Pro
Joined: Apr 2014
Posts: 614
Likes: 186
From: Orlando, Dundee, Val-des-Monts PQ
Rick, Don't let the "Debbie downers" discourage you. I think you did ok. As you said it's black, 4 speed, 2 door sports car with t-tops. I would not put much more money in the motor, save up and get a crate motor and put the goodies on the new motor. You don't have to roast the tires to look cool. Mark
Drifting
Joined: Aug 2009
Posts: 1,346
Likes: 160
From: new iberia la
Ignore the nay sayers.. you bought it, so obviously you liked something about it....$5K is cheap...besides The L-82 bottom end is 4 bolt and Forged , basically a later version of an early LT1 ,with less compression.. which is good for boost.. 5psi boost is not extreme.. your bottom end should hold just fine. .. ENJOY 
CF Community Team
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From: Pittsburgh
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From the pics that you posted, the usual suspects appear.... the car needs new exhaust, shocks, bushings, suspension parts in general, all of these items can be replaced at a cost. The frame & birdcage? A L82 with a blower on it & the hood cut open.
I would drive the car as is seeing that you don't have a lot of $$$ in it, if you want to go further, this car will require lots of cash to improve
I would drive the car as is seeing that you don't have a lot of $$$ in it, if you want to go further, this car will require lots of cash to improve
Le Mans Master
Joined: Oct 2010
Posts: 6,930
Likes: 845
From: melbourne florida
2023 C3 of the Year Finalist - Modified
Im with fishslayer it's a great bottom end. You need headers and 2 1/2 in exhaust and get it tuned. It will scream. Good luck I think you did fine!
Racer
Joined: Jan 2015
Posts: 293
Likes: 43
From: Vernon B.C.
I think you got a great deal on it! If the engine was in good shape to start with 5 psi should be nothing for it. Like someone mentioned L82s had forged internals and would be a solid foundation for what your doing. I would do a leak down and compression test on the engine to see what condition its in and go from there. If you had to and given the choice I would rebuild the original engine rather than buy a crate engine. A good custom engine builder will always supply a better product. I would open up the exhaust like you planning and take it from there. Anyway looks like a cool car that`ll be a lot of fun!
Melting Slicks
Joined: Dec 2009
Posts: 3,229
Likes: 656
From: Thunder Bay
You got that for $5K? You did great. Enjoy it. Don't expect it to be reliable, and expect to spend money on it. You can also expect to have fun with it. Congratulations.
FWIW it looks better than my car did when I started. Start with the safety stuff - suspension, brakes, tires. Make sure the frame is sound. Go from there.
FWIW it looks better than my car did when I started. Start with the safety stuff - suspension, brakes, tires. Make sure the frame is sound. Go from there.
