C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

better power, more mpg

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Old 11-21-2017, 06:43 AM
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Charsel
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Default better power, more mpg

First post, so excuse me if being redundant with question. Just bought '95 conv 6m. Just has magna flow cat back. From what I have read on Corvette Forum, LT1 likes to breathe. I doing air box cutout and Green Filter, coolant by-pass. Long tubes w/ cats and 1.60 rockers, maybe Hot Cam and tune when funds available. This is my daily driver for next 5 yrs. Any big hits on mpg? Right now, getting 19-26. Thanks
Old 11-21-2017, 07:41 AM
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The cam will drop your MPG
Old 11-21-2017, 08:14 AM
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Joe C
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what's your end goal for the car? strictly a daily driver, or are you planning on tracking the car? if strictly a DD, personally, i'd save the money. I surely wouldn't open up the engine for a hot cam just for a saturday night cruiser, driving back and forth to work, or down the local grocery store for a quart of milk and a loaf of bread. in current form, your LT1 will break any posted speed limit, anything beyond that is overkill. I found that my 96 LT1's 300 HP was more than adequate for the street. but, and however, your car, your money. if you build horsepower, you will have to feed those ponies. your overall gas mileage will drop. just my 2-cents....
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Old 11-21-2017, 09:35 AM
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QCVette
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Welcome to the forum.

We like pictures, so show us what you got and tell us about it. A '95 6M sounds good (but I am partial since I have a '95 6M too.)

The air box cutout, Green Filter and coolant by-pass are all minor things that you probably won't be able to notice any improvements, but they also are very low cost.

Long tubes w/ cats can add power. On some cars it can affect the fuel mixture and can cause some loss in mileage. With a tune, long tubes will help both power and mpg. They are my favorite mod.

1.60 rockers add some power and can lose a slight amount of mpg. They are an easy upgrade that can help some.

I would start with the longtubes, 1.60 rockers, and a tune. Should add a little power and keep good mileage.

The hot cam is a lot more work, but it does offer more performance. It will also drop a little mileage.

I would suggest driving the car a while before making many changes. Get used to it and see what you think needs to be sorted out on a "new" car. Then, after getting it in good shape and knowing what you have it may be time to decide if you want to mod it or not. These cars are pretty good stock and it may be enough.

Good luck
Old 11-21-2017, 11:56 AM
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Your right foot has a large say in what the mpg will be. Question is how far you can afford to go. So budget will be important.
Old 11-21-2017, 12:06 PM
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I agree with others. Drive the car, enjoy it, get used to it. If you just got it, you haven't yet explored the power level it has or doesn't have. The driver's mod is probably more important than any of the mod's you listed. Get used to driving the manual and being able to get the power to the ground and being able to corner and launch proficiently. If then, you find you need more power, go for it. Just remember a stock car is the most reliable car out there. When you start going into the motor, things can happen.
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Old 11-21-2017, 03:45 PM
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Mr. Peabody
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Welcome!! Be sure to post some pictures as that is what we all want to see.

If this is your first corvette I would caution you to exercise care going around corners.... resist the urge to "put your foot into it" going around corners. This car has a lot of torque and it is very easy to break the rear end loose going round a corner
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Old 11-21-2017, 04:39 PM
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Pick one mpg or power
Old 11-21-2017, 05:18 PM
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mtwoolford
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did a hot cam swap in a 96 coupe with 6M, on long, flat (boring) commute of 100 miles or so, didn't notice a drop in miles per; maybe a little better than your posted mpg, but then again the coupe might be a little more slippery than a convertible.
Old 11-21-2017, 06:51 PM
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Originally Posted by Mr. Peabody
Welcome!! Be sure to post some pictures as that is what we all want to see.

If this is your first corvette I would caution you to exercise care going around corners.... resist the urge to "put your foot into it" going around corners. This car has a lot of torque and it is very easy to break the rear end loose going round a corner
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Old 11-21-2017, 06:57 PM
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Originally Posted by QCVette
Welcome to the forum.

We like pictures, so show us what you got and tell us about it. A '95 6M sounds good (but I am partial since I have a '95 6M too.)

The air box cutout, Green Filter and coolant by-pass are all minor things that you probably won't be able to notice any improvements, but they also are very low cost.

Long tubes w/ cats can add power. On some cars it can affect the fuel mixture and can cause some loss in mileage. With a tune, long tubes will help both power and mpg. They are my favorite mod.

1.60 rockers add some power and can lose a slight amount of mpg. They are an easy upgrade that can help some.

I would start with the longtubes, 1.60 rockers, and a tune. Should add a little power and keep good mileage.

The hot cam is a lot more work, but it does offer more performance. It will also drop a little mileage.

I would suggest driving the car a while before making many changes. Get used to it and see what you think needs to be sorted out on a "new" car. Then, after getting it in good shape and knowing what you have it may be time to decide if you want to mod it or not. These cars are pretty good stock and it may be enough.

Good luck
Photo it is, not great one. Had for almost 1 month, haven't pushed it yet. Maybe this weekend if no rain, get up early and hit a back road
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Old 11-21-2017, 08:24 PM
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Originally Posted by mtwoolford
did a hot cam swap in a 96 coupe with 6M, on long, flat (boring) commute of 100 miles or so, didn't notice a drop in miles per; maybe a little better than your posted mpg, but then again the coupe might be a little more slippery than a convertible.
Isn't the hotcam "computer friendly" aka pretty close to stock window of adjustment? Probably won't notice much more than stock for mpg reduction, condition to condition comparison, I imagine.
Old 11-21-2017, 10:14 PM
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Originally Posted by Charsel
First post, so excuse me if being redundant with question. Just bought '95 conv 6m. Just has magna flow cat back. From what I have read on Corvette Forum, LT1 likes to breathe. I doing air box cutout and Green Filter, coolant by-pass. Long tubes w/ cats and 1.60 rockers, maybe Hot Cam and tune when funds available. This is my daily driver for next 5 yrs. Any big hits on mpg? Right now, getting 19-26. Thanks

Photo of my 'vette
Attachment 48227776
She is a beauty!

I feel the need to share the wisdom I have gained after owning an LT1 car for ten years now and having played my games with throttle body coolant deleting, throttle body airfoil, and experimenting with how modifications effected my average city and combined mileage.

The equation is very simple and it can not be altered, anytime you feed more air into the motor, more fuel will be burnt to produce more power! The PCM will always make the necessary adjustments. If you are concerned about fuel economy but still long for "power", maybe what you seek is more of the thrills provided by off idle low rpm to mid-range torque production, that seat of the pants feel and instant gratification. I am currently looking into the ZZ4 camshaft for my LT1, or a custom grind based on the ZZ4, giving me lots of vacuum production like a tow camshaft. From what I have researched, the ZZ4 camshaft is almost on par with the Hot Cam with the exception that it's power is created lower in the RPM band than the Hot Cam BUT with the right modifications, your stock LT1 intake manifold, 1.7 RRs, improved heads, and long tube headers, it can match and even surpass the Hot Cam while using up less fuel in it's power production! Then, pair this with your attempts to flow more air and cooler air into the motor and you should be making some good power.

Here is one of the better reference threads I stumbled upon:
https://www.z28.com/threads/question...zz4-cam.29325/

For my needs and my notion of "performance", I am likely going to have my car set-up to run warm engine bay air by keeping my throttle body coolant line, continuing to use paper air filters instead of cotton-gauze higher flowing filters, and maintaining the stock intake system which will help me optimize my altered motor for fuel efficiency, which was the goal from the factory!

Last edited by Phoenix'97; 11-21-2017 at 10:15 PM.
Old 11-21-2017, 11:20 PM
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Originally Posted by Phoenix'97
The equation is very simple and it can not be altered, anytime you feed more air into the motor, more fuel will be burnt to produce more power! The PCM will always make the necessary adjustments.
To a point, the ECM will. Beyond that, well....
Old 11-22-2017, 06:01 AM
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Charsel
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Originally Posted by Phoenix'97
She is a beauty!

I feel the need to share the wisdom I have gained after owning an LT1 car for ten years now and having played my games with throttle body coolant deleting, throttle body airfoil, and experimenting with how modifications effected my average city and combined mileage.

The equation is very simple and it can not be altered, anytime you feed more air into the motor, more fuel will be burnt to produce more power! The PCM will always make the necessary adjustments. If you are concerned about fuel economy but still long for "power", maybe what you seek is more of the thrills provided by off idle low rpm to mid-range torque production, that seat of the pants feel and instant gratification. I am currently looking into the ZZ4 camshaft for my LT1, or a custom grind based on the ZZ4, giving me lots of vacuum production like a tow camshaft. From what I have researched, the ZZ4 camshaft is almost on par with the Hot Cam with the exception that it's power is created lower in the RPM band than the Hot Cam BUT with the right modifications, your stock LT1 intake manifold, 1.7 RRs, improved heads, and long tube headers, it can match and even surpass the Hot Cam while using up less fuel in it's power production! Then, pair this with your attempts to flow more air and cooler air into the motor and you should be making some good power.

Here is one of the better reference threads I stumbled upon:
https://www.z28.com/threads/question...zz4-cam.29325/

For my needs and my notion of "performance", I am likely going to have my car set-up to run warm engine bay air by keeping my throttle body coolant line, continuing to use paper air filters instead of cotton-gauze higher flowing filters, and maintaining the stock intake system which will help me optimize my altered motor for fuel efficiency, which was the goal from the factory!
Thanks for the info. Sorry pic is overwhelming. All good points. There's a tuner in Tampa, but site indicates only does C5 and newer. Anybody know of a tuner who does C4s in Tampa Bay Area. Can't do mail order due to down time. DIY looks to make my head hurt, was much easier tuning '67 MGB
Old 11-22-2017, 08:44 AM
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Originally Posted by Charsel
Thanks for the info. Sorry pic is overwhelming. All good points. There's a tuner in Tampa, but site indicates only does C5 and newer. Anybody know of a tuner who does C4s in Tampa Bay Area. Can't do mail order due to down time. DIY looks to make my head hurt, was much easier tuning '67 MGB
Dynojet makes the dyno many use. Maybe you can ask them?
Old 11-22-2017, 09:03 AM
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Originally Posted by Charsel
Thanks for the info. Sorry pic is overwhelming. All good points. There's a tuner in Tampa, but site indicates only does C5 and newer. Anybody know of a tuner who does C4s in Tampa Bay Area. Can't do mail order due to down time. DIY looks to make my head hurt, was much easier tuning '67 MGB
Don't apologize, I prefer bigger pictures as you can see more details!

Whatever you have planned for your vette I am sure it will turn out wonderful. I found a thread for the C4 where it was recommended to dynotune at Jeremy Formato Fasterproms in Lutz, Florida.

http://www.digitalcorvettes.com/foru.../t-118578.html

http://www.fasterproms.net/services.html

I would send this guy an e-mail or call his business to see if he can help you out. His site advertises work done on newer Corvettes but I don't see why he can't work on your C4. Hope this helps.

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Old 11-22-2017, 09:52 AM
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Originally Posted by Charsel
Photo it is, not great one. Had for almost 1 month, haven't pushed it yet. Maybe this weekend if no rain, get up early and hit a back road
Having own my 93 since day one i would not do any mods! If you want power buy a Z06 the LT1 are a lot of problems ,and they all look good but i wish i dumped mine twenty years aga. Now my 77 L-82 4 speed car i would never give away it easy to work on and parts are easy to find and it feels like a real corvette !
Old 11-22-2017, 10:09 AM
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Originally Posted by Charsel
Can't do mail order due to down time. DIY looks to make my head hurt, was much easier tuning '67 MGB
When I did my hot cam I used pcmforless.com for their mail order service. They offered a service to source a replacement pcm so there was no downtime, I don't recall exactly how much it was but I do know it wasn't outrageous.
Old 11-22-2017, 11:58 AM
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Originally Posted by fake
Having own my 93 since day one i would not do any mods! If you want power buy a Z06 the LT1 are a lot of problems ,and they all look good but i wish i dumped mine twenty years aga. Now my 77 L-82 4 speed car i would never give away it easy to work on and parts are easy to find and it feels like a real corvette !
A little late for that. I was looking for a Z06, but this will do. I know optispark has issues, but having owned a '67 MGB and am some what mechanically inclined. Like the MG, can get parts anywhere, and what I can't fix my mechanic can (he checked out the car before I bought it).

Like all cars, if I don't want problems, I'll ride my bike


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