Corvettes in NASA ST1 Question
01-31-2012, 10:51 AM
#1
Le Mans Master
Thread Starter
Corvettes in NASA ST1 Question
Hey guys, I'm working on a project (more theory than anything else at this point) and it leads me to asking this question of you:
How hard is it to get a Corvette (whether a C5/C6 or LS6/LS2/LS3/LS7) to NASA's 5.5:1 ST1 ratio? Are the motors too stressed out? Is it difficult to get the weight out of the car?
Thank you in advance for any insight you provide.
DMP
How hard is it to get a Corvette (whether a C5/C6 or LS6/LS2/LS3/LS7) to NASA's 5.5:1 ST1 ratio? Are the motors too stressed out? Is it difficult to get the weight out of the car?
Thank you in advance for any insight you provide.
DMP
01-31-2012, 11:00 AM
#2
Safety Car
They're easy to make light. I've got my car down to 2850 w/o me in it and 1/2 tank of fuel. I could go lighter with lexan and fancy carbon body panels etc. If you were using a C6Z with an aluminum frame it'd be another 100lbs lighter.
For some reason the LS2/3/7 have had oiling issues unless properly dry sumped vs. the LS6 which seems to do OK wet sump (well unless you're Danny Popp). Also, the LS7 was having a valve guide wear issue from side loading of the off-set rocker arms. Lots of posts in the C6Z section about broken valves.
I'd start with a steel chassis, ACP or Blackdog race body panels, and then dry sump whatever motor you decided to go with. Check out RMackintosh's build thread "And so it begins..." for a nice all out build.
http://forums.corvetteforum.com/auto...it-begins.html
For some reason the LS2/3/7 have had oiling issues unless properly dry sumped vs. the LS6 which seems to do OK wet sump (well unless you're Danny Popp). Also, the LS7 was having a valve guide wear issue from side loading of the off-set rocker arms. Lots of posts in the C6Z section about broken valves.
I'd start with a steel chassis, ACP or Blackdog race body panels, and then dry sump whatever motor you decided to go with. Check out RMackintosh's build thread "And so it begins..." for a nice all out build.
http://forums.corvetteforum.com/auto...it-begins.html
01-31-2012, 11:35 AM
#3
Drifting
Dave,
You can build a competitive ST1 car without stressing engine if you decide to take the penalty for slicks. i.e. 6.2 lbs per HP.
George Smith won ST1 at Nationals in 2010 on slicks. Aaron Pfadt had a car just as fast that year (a stock LS7 engine with 3 seasons on it) on slicks. Both were dry sump cars.
At 3000 lbs that would put you at approx. 485 HP, which I think you can make very dependable, whether you use an LS3 or an LS7.
On DOT's at 3000 lbs. that is approx. 545 HP. or approx. 640 HP engine (a viper engine). That means camshafts above .625 and probably Jessel rocker shafts etc., etc, etc on an LS engine.
J.R.
You can build a competitive ST1 car without stressing engine if you decide to take the penalty for slicks. i.e. 6.2 lbs per HP.
George Smith won ST1 at Nationals in 2010 on slicks. Aaron Pfadt had a car just as fast that year (a stock LS7 engine with 3 seasons on it) on slicks. Both were dry sump cars.
At 3000 lbs that would put you at approx. 485 HP, which I think you can make very dependable, whether you use an LS3 or an LS7.
On DOT's at 3000 lbs. that is approx. 545 HP. or approx. 640 HP engine (a viper engine). That means camshafts above .625 and probably Jessel rocker shafts etc., etc, etc on an LS engine.
J.R.
01-31-2012, 02:16 PM
#6
Pro
Pro Mechanic
Its real hard & not reliable at all.
Stay in a snake I like having dodge competition. Just kidding. I have built a couple snakes. 1 was 1000hp. The vette is cheaper in all aspects. Your not going to be running a stock engine . Built LS engines are cheaper much more competition. I'm having trouble only making required power.
Stay in a snake I like having dodge competition. Just kidding. I have built a couple snakes. 1 was 1000hp. The vette is cheaper in all aspects. Your not going to be running a stock engine . Built LS engines are cheaper much more competition. I'm having trouble only making required power.
Last edited by John B; 01-31-2012 at 02:26 PM.
02-01-2012, 10:55 AM
#8
Pro
Pro Mechanic
The stroke of a 6.2 or 7.0 would not need to be increased to get to 500-550rwhp. You would need a quality race build of the engine for longevity. The more pieces you remove the lighter the car. In my case we completely stripped,sandblasted frame & built from there. What exactly are you getting at here? Feel free to call me if you would like.
02-01-2012, 11:33 AM
#9
Burning Brakes
The stroke of a 6.2 or 7.0 would not need to be increased to get to 500-550rwhp. You would need a quality race build of the engine for longevity. The more pieces you remove the lighter the car. In my case we completely stripped,sandblasted frame & built from there. What exactly are you getting at here? Feel free to call me if you would like.
02-01-2012, 12:05 PM
#10
Le Mans Master
Thread Starter
The stroke of a 6.2 or 7.0 would not need to be increased to get to 500-550rwhp. You would need a quality race build of the engine for longevity. The more pieces you remove the lighter the car. In my case we completely stripped,sandblasted frame & built from there. What exactly are you getting at here? Feel free to call me if you would like.
One idea I have is to move to a "power-to-weight ratio" type of class. But before I do that I want to make sure that certain cars can "get there" within reason. Since NASA's ST1 5.5:1 is one of the more aggressive ratios out there, that's why I asked about meeting its number.
The one concern I do have is how to effectively monitor these numbers. So many people have said in different discussions that it is pretty easy to "cheat" the chassis dyno. I know NARRA uses Traqmate as a back-up, and they claim the biggest discrepancy they've seen is 9 HP.
02-01-2012, 01:13 PM
#12
Burning Brakes
I have been asked by a sanctioning body for ideas on how to increase participation in certain classes. I don't have any authority, but I can express my opinion.
One idea I have is to move to a "power-to-weight ratio" type of class. But before I do that I want to make sure that certain cars can "get there" within reason. Since NASA's ST1 5.5:1 is one of the more aggressive ratios out there, that's why I asked about meeting its number.
The one concern I do have is how to effectively monitor these numbers. So many people have said in different discussions that it is pretty easy to "cheat" the chassis dyno. I know NARRA uses Traqmate as a back-up, and they claim the biggest discrepancy they've seen is 9 HP.
One idea I have is to move to a "power-to-weight ratio" type of class. But before I do that I want to make sure that certain cars can "get there" within reason. Since NASA's ST1 5.5:1 is one of the more aggressive ratios out there, that's why I asked about meeting its number.
The one concern I do have is how to effectively monitor these numbers. So many people have said in different discussions that it is pretty easy to "cheat" the chassis dyno. I know NARRA uses Traqmate as a back-up, and they claim the biggest discrepancy they've seen is 9 HP.
Sadly people are always going to find a way to cheat and we are just club racing for some of the cheapest trophies you can find... yeah some tires for some and even some contingencies, but at the end of the day, it is clubracing.
02-01-2012, 02:03 PM
#13
Drifting
For monitoring, just take a look at the threads we have on the NASA forums. Whatever you suggest, the rules and requirements and monitoring devices MUST be the same for ALL competitors.
For instance, at NASA Nationals, I am subject to dyno testing via a dyno on site and acquisition data via a device they install in my car. However, they only bring a 2wd dyno to the event. So an AWD car never has to go across the dyno, they are only subject to the data acquistion. The reason this is not fair is because I can be disqualified for being one (1) horsepower over my limit on the dyno. Yet that same one hp will not show up on data acquisition, therefore the AWD car is not subject to the same scrutiny as the 2wd car.
-Kevin
For instance, at NASA Nationals, I am subject to dyno testing via a dyno on site and acquisition data via a device they install in my car. However, they only bring a 2wd dyno to the event. So an AWD car never has to go across the dyno, they are only subject to the data acquistion. The reason this is not fair is because I can be disqualified for being one (1) horsepower over my limit on the dyno. Yet that same one hp will not show up on data acquisition, therefore the AWD car is not subject to the same scrutiny as the 2wd car.
-Kevin
02-01-2012, 03:29 PM
#14
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For monitoring, just take a look at the threads we have on the NASA forums. Whatever you suggest, the rules and requirements and monitoring devices MUST be the same for ALL competitors.
For instance, at NASA Nationals, I am subject to dyno testing via a dyno on site and acquisition data via a device they install in my car. However, they only bring a 2wd dyno to the event. So an AWD car never has to go across the dyno, they are only subject to the data acquistion. The reason this is not fair is because I can be disqualified for being one (1) horsepower over my limit on the dyno. Yet that same one hp will not show up on data acquisition, therefore the AWD car is not subject to the same scrutiny as the 2wd car.
-Kevin
For instance, at NASA Nationals, I am subject to dyno testing via a dyno on site and acquisition data via a device they install in my car. However, they only bring a 2wd dyno to the event. So an AWD car never has to go across the dyno, they are only subject to the data acquistion. The reason this is not fair is because I can be disqualified for being one (1) horsepower over my limit on the dyno. Yet that same one hp will not show up on data acquisition, therefore the AWD car is not subject to the same scrutiny as the 2wd car.
-Kevin
I can see not having one in regional races, but it's a must at Nationals IMO.
02-01-2012, 04:14 PM
#15
Melting Slicks
Hey guys, I'm working on a project (more theory than anything else at this point) and it leads me to asking this question of you:
How hard is it to get a Corvette (whether a C5/C6 or LS6/LS2/LS3/LS7) to NASA's 5.5:1 ST1 ratio? Are the motors too stressed out? Is it difficult to get the weight out of the car?
Thank you in advance for any insight you provide.
DMP
How hard is it to get a Corvette (whether a C5/C6 or LS6/LS2/LS3/LS7) to NASA's 5.5:1 ST1 ratio? Are the motors too stressed out? Is it difficult to get the weight out of the car?
Thank you in advance for any insight you provide.
DMP
To answer your question, It is not hard to get weight out of a Corvette or to make enough power to run in a 5.5:1 class. It is just expensive....as it is with any car at that pwr/wt ratio.
Hell, my car had to be ballasted to make the class and I had a small displacement engine.
02-01-2012, 04:23 PM
#16
Melting Slicks
OEM LS6's seem to be ok, as the original engine was in James' car until RA in Dec. of 2010. That engine lasted for 6 years no issues , until bang-o. The replacement engine ( which was a late production CTSV engine) only lasted 6 months in the same environment, same engine speeds. James and I discovered when taking somethings apart, that the premature anaylsis was incorrect about oil starving the engine as the rod journal of the escaped rod was not heated , or spun. Seems to be rod bolt failure. All engines are not the same, the last one while fast, was not as good as the first one which was also fast and lasted ALOT longer.
02-01-2012, 04:29 PM
#18
Le Mans Master
Thread Starter
Dave,
To answer your question, It is not hard to get weight out of a Corvette or to make enough power to run in a 5.5:1 class. It is just expensive....as it is with any car at that pwr/wt ratio.
Hell, my car had to be ballasted to make the class and I had a small displacement engine.
To answer your question, It is not hard to get weight out of a Corvette or to make enough power to run in a 5.5:1 class. It is just expensive....as it is with any car at that pwr/wt ratio.
Hell, my car had to be ballasted to make the class and I had a small displacement engine.
I don't know if this will go anywhere, but I am bringing it up for discussion with the "powers to be."
02-01-2012, 07:01 PM
#19
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Dave.. Can you mention to them about the ST2 class. Just like Alex mentioned we (ST2) have alot of cars that are not T1 legal but not quite up to STO power levels. Having another place to play would help grow both racing orgs.
02-01-2012, 07:26 PM
#20
Racer
