1977 L48 dyno
Le Mans Master
Joined: Jun 2004
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From: Seattle WA
St. Jude Donor '14
There's 3 ways that come to mind that would document the cam installed retarded; either the cam/timing gears were different, or the cam was installed with different-than standard positioning of the cam/crank sprockets. The first two would generate alternate part numbers, the latter would be clearly documented in the factory service manual - fair? I would think anyone making this claim could do a little research and easily and quickly find out how (and if) this was done using standard and readily-available references 
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I am not in IT I actually write software and I can make a stock L48 put out 500 RWHP 
Always turns into a pizzing match, between people that know what they are talking about, some that have their own ideas and others that simply don't know too much about dynos ( this is not a put down ) and are asking legitimate questions based on this fact.
My friend owns a 20,000 sq/ft engine shop and has a properly calibrated engine dyno and chassis dyno. He told me he had a Viper day ( Viper club ) and they put thier Vipers on his properly calibrated chassis dyno and he said he never saw so many long faces in his life to to the point where some of them were saying his dyno was no good and not properly calibrated. Now are these guys coming back, no, but he builds engines for serious racing teams and needs to know the real numbers.
Bottom line, never tell a dyno shop how much HP you think your car will make, in almost all cases I have seen this question is asked
Always turns into a pizzing match, between people that know what they are talking about, some that have their own ideas and others that simply don't know too much about dynos ( this is not a put down ) and are asking legitimate questions based on this fact.
My friend owns a 20,000 sq/ft engine shop and has a properly calibrated engine dyno and chassis dyno. He told me he had a Viper day ( Viper club ) and they put thier Vipers on his properly calibrated chassis dyno and he said he never saw so many long faces in his life to to the point where some of them were saying his dyno was no good and not properly calibrated. Now are these guys coming back, no, but he builds engines for serious racing teams and needs to know the real numbers.
Bottom line, never tell a dyno shop how much HP you think your car will make, in almost all cases I have seen this question is asked
Race Director
Joined: May 2003
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From: California
Gosh I love dyno threads.... Always a good banter ..
I remember one, if not the first, Post I ever made here was a dyno thread.... I had just picked up my car from a local shop, R&E Racing... They gave me a report that showed something like 550 hp and 500tq at the rear wheels!!! Man was I excited!!! I posted my results.... Lol..... Then gkull and I think 63mako took me to task on the numbers... They were right... Broke my hart... And made me pissed at R&E Racing for the bull.... Went back and then they told me ther dyno was not working right after an AC failure...... Yea, right....
I remember one, if not the first, Post I ever made here was a dyno thread.... I had just picked up my car from a local shop, R&E Racing... They gave me a report that showed something like 550 hp and 500tq at the rear wheels!!! Man was I excited!!! I posted my results.... Lol..... Then gkull and I think 63mako took me to task on the numbers... They were right... Broke my hart... And made me pissed at R&E Racing for the bull.... Went back and then they told me ther dyno was not working right after an AC failure...... Yea, right....
Last edited by pauldana; Oct 5, 2012 at 12:21 PM.
Le Mans Master
Joined: Mar 2008
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From: Oxford MA-----You just lost the game!!!!
Gosh I love dyno threads.... Always a good banter ..
I remember one, if not the first, Post I ever made here was a dyno thread.... I had just picked up my car from a local shop, R&E Racing... They gave me a report that showed something like 550 hp and 500tq at the rear wheels!!! Man was I excited!!! I posted my results.... Lol..... Then gkull and I think 63mako took me to task on the numbers... They were right... Broke my hart... And made me pissed at R&E Racing for the bull.... Went back and then they told me ther dyno was not working right after an AC failure...... Yea, right....
I remember one, if not the first, Post I ever made here was a dyno thread.... I had just picked up my car from a local shop, R&E Racing... They gave me a report that showed something like 550 hp and 500tq at the rear wheels!!! Man was I excited!!! I posted my results.... Lol..... Then gkull and I think 63mako took me to task on the numbers... They were right... Broke my hart... And made me pissed at R&E Racing for the bull.... Went back and then they told me ther dyno was not working right after an AC failure...... Yea, right....
Keep the shiny side up!
Scott
Le Mans Master
Joined: Oct 2000
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From: Santa Ana CA
I find that it is actually getting harder to make the "number."
I've been chasing 300 RWHP (dynos show the 280s - 290s) and while I've done mods that theoretically should yield small gains (e.g., Gilmer belt underdrive that CarCraft found 10 hp at 5,500 RPM with on their dyno), I find find less RWHP in the more recent print-outs than before the mods.
I've been told that the software updates are making the legit dynos print lower numbers than in the past, so while there may actually have been an increase in power, it doesn't show up in the printout.
I've been chasing 300 RWHP (dynos show the 280s - 290s) and while I've done mods that theoretically should yield small gains (e.g., Gilmer belt underdrive that CarCraft found 10 hp at 5,500 RPM with on their dyno), I find find less RWHP in the more recent print-outs than before the mods.
I've been told that the software updates are making the legit dynos print lower numbers than in the past, so while there may actually have been an increase in power, it doesn't show up in the printout.
Last edited by toddalin; Oct 5, 2012 at 02:38 PM.
Race Director
Joined: May 2003
Posts: 10,956
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From: California
So........if they are telling the truth, they were charging people full price to run their cars on a dyno that they knew was giving faulty data? That's their exuse? Man, that's even more unethical than running a "happy dyno", in my opinion. Some people try to explain there way out of things, and end up making themselves look even worse. As my Grandpappy used to say, "Scottarino, you'll never get out of a hole by digging it deeper. When you find yourself in a hole, the first thing you need to do is........STOP DIGGING!"
Keep the shiny side up!
Scott
Keep the shiny side up!
Scott
on the digging a hole thing.....Yea, I do that sometimes also... sometimes when your in that hole you dont even know it.... tis life...
Last edited by pauldana; Oct 6, 2012 at 08:25 PM.
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Good luck at the track. Looking forward to the results.
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Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Le Mans Master
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From: Lebanon Township New Jersey
Shark Racer - I have to admit I was wrong. I looked up 77 L48 specs in some Corvette books I have and they show that the L48 was rated at 180hp at 4,000 rpm. I'm speechless.
Race Director
Joined: Jan 2000
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From: San Jose CA
I was almost afraid when I did heads/cam to push past 5k.
Once I've got this carb dialed in I'm hoping for 6k. lolThe cam is very, very, very mild. With good tuning I'd bet you could idle it down to 400 RPM.
Melting Slicks
Joined: Aug 2010
Posts: 2,487
Likes: 10
From: Palm Beach Florida
St. Jude Donor '12
This is the best thing I've seen yet in this thread. I'm not a fan of dyno racing. Particularly considering all the happy dyno, innaccurate dyno, correction factor etc. issues such as we've heard here. The true test of how a car performs, in terms of acceleration, is how quick can it cover a measured distance, from a standing start.
Good luck at the track. Looking forward to the results.
Good luck at the track. Looking forward to the results.
Why pay to have your car on a machine. You should be able to notice all the little changes you make to your own car. Seat of the pants still works for me.
Race Director
Joined: Apr 2000
Posts: 17,676
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
10 hp more could win you a race or 10hp less you could lose. If you can feel that at 6000RPM then your right you don't need a dyno.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
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From: Seattle WA
St. Jude Donor '14
Le Mans Master
Joined: May 2002
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From: Lebanon Township New Jersey
I don't doubt the usefulness of dyno tuning. What I have a problem with is guys everywhere bragging about their big dyno numbers with no impressive track data to match it. Guys at car shows with dyno graphs on their windshields implying that that equals a certain impressive ET on a track. It doesn't. Its true that without a certain amount of power you can't run a certain ET/MPH. But its also true that reaching those power levels on a dyno doesn't come close to running those numbers on a track.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
I don't doubt the usefulness of dyno tuning. What I have a problem with is guys everywhere bragging about their big dyno numbers with no impressive track data to match it. Guys at car shows with dyno graphs on their windshields implying that that equals a certain impressive ET on a track. It doesn't. Its true that without a certain amount of power you can't run a certain ET/MPH. But its also true that reaching those power levels on a dyno doesn't come close to running those numbers on a track.
Melting Slicks
Joined: Aug 2011
Posts: 3,137
Likes: 261
I don't doubt the usefulness of dyno tuning. What I have a problem with is guys everywhere bragging about their big dyno numbers with no impressive track data to match it. Guys at car shows with dyno graphs on their windshields implying that that equals a certain impressive ET on a track. It doesn't. Its true that without a certain amount of power you can't run a certain ET/MPH. But its also true that reaching those power levels on a dyno doesn't come close to running those numbers on a track.
BK I can't believe that there are braggards who actually display their dyno graph's on their windshields !! What a bunch of LOSERS !!
You want to impress people / prove something - show us your ET tickets.
Might as well not bother with the trouble of building and bringing a car - let's just bring motors on the back of pick-ups and have a portable dyno to move from one to the other - makes just as much sense !
The dyno shop's / engine builders just love this stuff LOL
Melting Slicks
Joined: Aug 2011
Posts: 3,137
Likes: 261
Having owned and driven one as my first car for many years I wasn't surprised. Motor never wanted to rev much past 4500.
I was almost afraid when I did heads/cam to push past 5k. Once I've got this carb dialed in I'm hoping for 6k. lol
The cam is very, very, very mild. With good tuning I'd bet you could idle it down to 400 RPM.
I was almost afraid when I did heads/cam to push past 5k.
Once I've got this carb dialed in I'm hoping for 6k. lolThe cam is very, very, very mild. With good tuning I'd bet you could idle it down to 400 RPM.
Drag strip "tuned" at annual Corvette drags (once a year) over the course of many years LOL.
Last edited by QIK59; Oct 6, 2012 at 07:44 PM.