What I have LEARNED
08-04-2015, 12:45 PM
#1
Pro
Thread Starter
What I have LEARNED
Hey,
I recently switched cars, and so I thought I'd use this point in time to compile and share a little learning. Mostly from experience, with solutions gleaned from here, of course, but also some useful info from some aero guys, race guys, some others. Maybe info of use to someone considering a blown car. Apologies on the length.
And yes, I LOVE my blown Vette. If you like a car that is crazy quick and fun to drive, that backs down from almost nothing, that always makes passengers GASP the first time you hit it, and can still peaceably drive the wife to a nice dinner and have the valet park it in front, this is a great choice.
I originally started in 2009 with an AO Base Vert that I ordered from the factory. I started with a base model so I could build it the way I wanted, and spend money on just the things I wanted. Thinking I would end up saving money over the price of say a ZR1. It was a good thought.
I wanted a blown car, road course capable, and around 200 top end. And this was to be my daily driver. So, 20K miles/year going on it of mostly back and forth in the Texas heat. Early on I added Bilsteins and stiffer sway bars. I tracked with just this, and quickly decided the tires had to go, that the Goodyears were good when new, but boy do they die off pretty quickly as they age. Then you spend months waiting for them to finish wearing, all the while with little grip. Michelin PS2s fixed that. Just in this configuration, it was a damn quick track car, not good enough to chase down the big boys, but eater of lots of other things, including a buddy's M5, which infuriated him to no end.
I also did a Bonneville run in stock form, just to have a baseline and see how a C6 Vette does. It was an eye-opening experience. Salt has about half the traction of asphalt. Rolling it up to big speed the first time, at around 160, the car started drifting sideways away from the racing line. Just literally moving out sideways while pointed straight ahead.
Wow is that disconcerting. Gentle lift off gas, let it get traction again, and try again. It took five full length attempts to get to top end, at 183. This in a base vert, at 4000' elevation (so, less HP).
This taught me about lift. In factory form, when traveling at speed air slams in through the radiator, and into the underhood space. It then has nowhere to go, so pressure builds, until it gets high enough to compress a bit and go out under the car. Meanwhile, the air flowing over the outside causes the area over the hood to create a low pressure zone there. High pressure below, low pressure above, et voila, the hood acts as a giant piston, lifting the nose of the car. Plus the high pressure air moving under the car pushes the whole car up as well. And the faster the speed, the greater the pressure difference, and hence the greater the lift. Data on this was VERY hard to track down, obviously not something GM would want to be trumpeting about. I finally found an article where someone used the Daimler wind tunnel in Germany and a stock C6, and got sufficient force on the nose to back flip the car at 240mph. And certainly enough lift at 160 or so to pull traction from the front tires on salt. Ewww. I also had a nice lunch with a longtime salt veteran, who told me about the first two ZR1s to show up at Bonneville, and how they both spun out at 200, sending showers of glass down the track. So, a vented hood was going to be a-comin'.
Once 50K arrived and the warranty lapsed, I had Dallas Performance do an A&A Vortech centri. I had picked the centri for the Bonneville runs, something that makes more power up top. If not for that, I might have stuck with a roots style for just street use. And turbos cost more, and I am cheap. We added nothing besides the blower kit to the car. I learned, that was not going to do it. Dynoed 557, and I was told by Taylor that was because it was a REAL optimal day for dynoing, don't expect that to happen again.
Started driving it, and just absolutely loved it. But I soon discovered the heat issue.
In the summer heat, the car did not like stop and go traffic, and would get hot. And the water temp tended to be higher or lower based on the air temp. I also did some test runs on the highway, where I would downshift to drive the RPM up, and leave it there for 30 seconds (cause, Bonneville runs are more like 2 minutes at full throttle). The car would quickly get very hot, and it would take quite a while to cool back down. So, hood first.
When I added the hood, back in 2012 or so, the ZL1 option had not been available, and most folks didn’t bother with louvers on C6s. I looked at the various options, and of course no one would publish real data. I decided to go with the ACS World Challenge hood. This one was actually developed in the GM wind tunnel for real race teams, and that was good enough for me.
With the hood added, traffic temps quit being such a problem. You could just watch the heat pour up out of all those vents. And driving around, the hood was moving lots of air. Indeed, with the low pressure over the top of the hood, it was likely accelerating airflow through the radiator, making it pull more BTUs. But still, in the 30 second pulls the car would get too hot. Needed to add more radiator.
I had a long-time racing engineer buddy tell me about how heat works in the engine. When one burns fuel, it turns to heat. About 1/3 of the heat is uses to expand gases and shove the pistons down, making HP. Another 1/3 just goes out the back as heating of the exhaust gases. And the other 1/3 just gets dumped into the block, heating up the oil and water. The water takes about 80% of the load, and the oil takes about 20%. My engine was making about 50% more HP than stock, so that much more heat was pouring into the block. The factory radiator simply was not designed to move that much heat into the air.
Interestingly, there is no industry standard test for how many BTUs a radiator can move. So what that leaves you with to make decisions on is a lot of anecdotal evidence, which tends to go all sorts of ways, and is mostly random noise. I finally decided to go with a C&R unit. C&R builds radiators for Indy and NASCAR cars, and those customers can afford the best. C&R was not the cheapest, but boy do they make a fat radiator. Had that installed, along with 60% water and some water wetter.
And poof, water temp problems were all good. Now it could take the 30 second pulls, no problem, and cool back down very quickly from what little they did rise. But the oil temps were still a problem, as they still rose quickly and took a while to come back down. Needed an oil cooler.
The problem with a traditional radiator-style oil cooler for my application, it doesn’t let the oil heat up very quickly when the engine is started cold, especially in daily driving. And having oil lines out in space was a bit concerning. So, I decided to go with a ZR1 oil/water intercooler. On a base LS3 this means adding (1) an extra fitting to the radiator, (2) a welded-on boss on the oil pan for the intercooler to bolt to, and (3) ZR1 exhaust manifolds to clear the intercooler.
And poof, no more oil temp problems. Where in the past the oil tended to run maybe 30 degrees hotter than the water, now they were locked together at the hip, staying within five degrees of each other all the time. When the oil would try to heat up too much, the water would yank it right back down. And as a bonus, the oil would heat up quicker on a cold start, as the water got hot quickly, and then would pull the oil temps quickly up. And now in daily driving, temps just went to the thermostat temp, and tended to stay there. Very hard to get them to go up, even in the Texas heat.
On track, this combination worked. Twenty minute sessions, no temp issues. I had also added ZO6 springs, and slightly bigger CCW wheels with Michelin PSS tires. Man did this combo work great. Pulling over 1g all day long, explosively quick on any straight, running down most of what I could see. Lord I need a racing seat, what a wrestling match to stay put.
Back to Bonneville, and the first run turned 193. At about 100mph, you felt the nose just plant hard to the ground, and it stayed firmly planted the entire run. Temps barely rose, and came back down quickly. Niiiiice. But it was clear that the louvered hood and the Ron Fellow rear spoiler I had added (only an inch or so tall) were now creating a lot of drag. Always the trade. I had had an aero expert tell me that the World Challenge hood was designed for road racing, to address both cooling and lift. For something like Bonneville, it was likely overkill, I might want to tape up maybe half of the louvers to improve aero. And indeed, I’d brought some racer tape just for the occasion, which could also be used to close up the radiator opening a bit as well.
But after the first run, checking everything, found the rear main had sprung a leak. This was yet another time that the blowby pressure was causing a problem. Needed to get that addressed. Stopped there, and headed back home.
I decided to add a couple catch cans, one RevExtreme, one someone else. That helped some, but I was still puffing smoke every time I’d floor it on the highway. My race buddy told me, it’s the oil, stupid. He went into a highly technical discussion about why Mobil One was not the oil I wanted for this application. So on his advice, I switched to Amsoil. And poof, no more blowby problems. Weird.
I added meth injection, just for some insurance. I used an Alky Controls unit. The last touch was a custom radiator mount, created by Lucas Auto Care in Houston, as the nose sat lower, even with the ride-height bolts about as far as they would go to lift it, and I’d managed to impact the lowered radiator a couple time, once bad enough to have to get it repaired. The custom piece was MUCH more solid, and angled up to try to push the radiator up if I struck it again.
The end of my orange car time came at around six years and 97K miles. The car acquired an electrical gremlin. You can read the details in another post. Several other folks on the forum have had similar issues, just a Vette thing that might happen to random cars. And mine did have lots of miles. Two months, three shops, and lots of my own attempts, and I finally gave up. But I still loved the combination I had built, and I wanted to keep it. So, after looking at $90K for a new ZO6 vert, as well as several other possibilities, I decided to track down another 2009 base vert. That took a couple weeks. AO was impossible to find, and so I settled for a low miles Arctic White with 3LT trim and the butterfly exhaust. Spent about $7K switching everything over between the cars, turning the white one into a beast, and returning the orange one to stock. During the midst of the work, a burnt wire was found under a header of the orange one.
This was fixed, and the gremlin was gone. Oh well, that’s the way it goes.
As I’m now in the Houston area, GForce did the tune on both cars. The white one, now using the meth, dyno’ed right at 600. I sold the orange one, and ended up out about $30K, to lose about 75K miles. That deal works for me, especially compared to the $90K for a new ZO6. Oh, I know I’m missing some upgrades, but I’ll bear up for now. And maybe add a forged engine sometime in the future.
And I am once again REALLY enjoying my ride. I still need to get back up to Bonneville, maybe this year, maybe next. And I haven’t had a chance to get on MSR-H yet, that should be fun. Re my personal choices, there are lots of ways to deal with the various issues, these just worked for me.
Story of the day.
I recently switched cars, and so I thought I'd use this point in time to compile and share a little learning. Mostly from experience, with solutions gleaned from here, of course, but also some useful info from some aero guys, race guys, some others. Maybe info of use to someone considering a blown car. Apologies on the length.
And yes, I LOVE my blown Vette. If you like a car that is crazy quick and fun to drive, that backs down from almost nothing, that always makes passengers GASP the first time you hit it, and can still peaceably drive the wife to a nice dinner and have the valet park it in front, this is a great choice.
I originally started in 2009 with an AO Base Vert that I ordered from the factory. I started with a base model so I could build it the way I wanted, and spend money on just the things I wanted. Thinking I would end up saving money over the price of say a ZR1. It was a good thought.
I wanted a blown car, road course capable, and around 200 top end. And this was to be my daily driver. So, 20K miles/year going on it of mostly back and forth in the Texas heat. Early on I added Bilsteins and stiffer sway bars. I tracked with just this, and quickly decided the tires had to go, that the Goodyears were good when new, but boy do they die off pretty quickly as they age. Then you spend months waiting for them to finish wearing, all the while with little grip. Michelin PS2s fixed that. Just in this configuration, it was a damn quick track car, not good enough to chase down the big boys, but eater of lots of other things, including a buddy's M5, which infuriated him to no end.
I also did a Bonneville run in stock form, just to have a baseline and see how a C6 Vette does. It was an eye-opening experience. Salt has about half the traction of asphalt. Rolling it up to big speed the first time, at around 160, the car started drifting sideways away from the racing line. Just literally moving out sideways while pointed straight ahead.
Wow is that disconcerting. Gentle lift off gas, let it get traction again, and try again. It took five full length attempts to get to top end, at 183. This in a base vert, at 4000' elevation (so, less HP).This taught me about lift. In factory form, when traveling at speed air slams in through the radiator, and into the underhood space. It then has nowhere to go, so pressure builds, until it gets high enough to compress a bit and go out under the car. Meanwhile, the air flowing over the outside causes the area over the hood to create a low pressure zone there. High pressure below, low pressure above, et voila, the hood acts as a giant piston, lifting the nose of the car. Plus the high pressure air moving under the car pushes the whole car up as well. And the faster the speed, the greater the pressure difference, and hence the greater the lift. Data on this was VERY hard to track down, obviously not something GM would want to be trumpeting about. I finally found an article where someone used the Daimler wind tunnel in Germany and a stock C6, and got sufficient force on the nose to back flip the car at 240mph. And certainly enough lift at 160 or so to pull traction from the front tires on salt. Ewww. I also had a nice lunch with a longtime salt veteran, who told me about the first two ZR1s to show up at Bonneville, and how they both spun out at 200, sending showers of glass down the track. So, a vented hood was going to be a-comin'.
Once 50K arrived and the warranty lapsed, I had Dallas Performance do an A&A Vortech centri. I had picked the centri for the Bonneville runs, something that makes more power up top. If not for that, I might have stuck with a roots style for just street use. And turbos cost more, and I am cheap. We added nothing besides the blower kit to the car. I learned, that was not going to do it. Dynoed 557, and I was told by Taylor that was because it was a REAL optimal day for dynoing, don't expect that to happen again.
Started driving it, and just absolutely loved it. But I soon discovered the heat issue.
In the summer heat, the car did not like stop and go traffic, and would get hot. And the water temp tended to be higher or lower based on the air temp. I also did some test runs on the highway, where I would downshift to drive the RPM up, and leave it there for 30 seconds (cause, Bonneville runs are more like 2 minutes at full throttle). The car would quickly get very hot, and it would take quite a while to cool back down. So, hood first.
When I added the hood, back in 2012 or so, the ZL1 option had not been available, and most folks didn’t bother with louvers on C6s. I looked at the various options, and of course no one would publish real data. I decided to go with the ACS World Challenge hood. This one was actually developed in the GM wind tunnel for real race teams, and that was good enough for me.
With the hood added, traffic temps quit being such a problem. You could just watch the heat pour up out of all those vents. And driving around, the hood was moving lots of air. Indeed, with the low pressure over the top of the hood, it was likely accelerating airflow through the radiator, making it pull more BTUs. But still, in the 30 second pulls the car would get too hot. Needed to add more radiator.
I had a long-time racing engineer buddy tell me about how heat works in the engine. When one burns fuel, it turns to heat. About 1/3 of the heat is uses to expand gases and shove the pistons down, making HP. Another 1/3 just goes out the back as heating of the exhaust gases. And the other 1/3 just gets dumped into the block, heating up the oil and water. The water takes about 80% of the load, and the oil takes about 20%. My engine was making about 50% more HP than stock, so that much more heat was pouring into the block. The factory radiator simply was not designed to move that much heat into the air.
Interestingly, there is no industry standard test for how many BTUs a radiator can move. So what that leaves you with to make decisions on is a lot of anecdotal evidence, which tends to go all sorts of ways, and is mostly random noise. I finally decided to go with a C&R unit. C&R builds radiators for Indy and NASCAR cars, and those customers can afford the best. C&R was not the cheapest, but boy do they make a fat radiator. Had that installed, along with 60% water and some water wetter.
And poof, water temp problems were all good. Now it could take the 30 second pulls, no problem, and cool back down very quickly from what little they did rise. But the oil temps were still a problem, as they still rose quickly and took a while to come back down. Needed an oil cooler.
The problem with a traditional radiator-style oil cooler for my application, it doesn’t let the oil heat up very quickly when the engine is started cold, especially in daily driving. And having oil lines out in space was a bit concerning. So, I decided to go with a ZR1 oil/water intercooler. On a base LS3 this means adding (1) an extra fitting to the radiator, (2) a welded-on boss on the oil pan for the intercooler to bolt to, and (3) ZR1 exhaust manifolds to clear the intercooler.
And poof, no more oil temp problems. Where in the past the oil tended to run maybe 30 degrees hotter than the water, now they were locked together at the hip, staying within five degrees of each other all the time. When the oil would try to heat up too much, the water would yank it right back down. And as a bonus, the oil would heat up quicker on a cold start, as the water got hot quickly, and then would pull the oil temps quickly up. And now in daily driving, temps just went to the thermostat temp, and tended to stay there. Very hard to get them to go up, even in the Texas heat.
On track, this combination worked. Twenty minute sessions, no temp issues. I had also added ZO6 springs, and slightly bigger CCW wheels with Michelin PSS tires. Man did this combo work great. Pulling over 1g all day long, explosively quick on any straight, running down most of what I could see. Lord I need a racing seat, what a wrestling match to stay put.
Back to Bonneville, and the first run turned 193. At about 100mph, you felt the nose just plant hard to the ground, and it stayed firmly planted the entire run. Temps barely rose, and came back down quickly. Niiiiice. But it was clear that the louvered hood and the Ron Fellow rear spoiler I had added (only an inch or so tall) were now creating a lot of drag. Always the trade. I had had an aero expert tell me that the World Challenge hood was designed for road racing, to address both cooling and lift. For something like Bonneville, it was likely overkill, I might want to tape up maybe half of the louvers to improve aero. And indeed, I’d brought some racer tape just for the occasion, which could also be used to close up the radiator opening a bit as well.
But after the first run, checking everything, found the rear main had sprung a leak. This was yet another time that the blowby pressure was causing a problem. Needed to get that addressed. Stopped there, and headed back home.
I decided to add a couple catch cans, one RevExtreme, one someone else. That helped some, but I was still puffing smoke every time I’d floor it on the highway. My race buddy told me, it’s the oil, stupid. He went into a highly technical discussion about why Mobil One was not the oil I wanted for this application. So on his advice, I switched to Amsoil. And poof, no more blowby problems. Weird.
I added meth injection, just for some insurance. I used an Alky Controls unit. The last touch was a custom radiator mount, created by Lucas Auto Care in Houston, as the nose sat lower, even with the ride-height bolts about as far as they would go to lift it, and I’d managed to impact the lowered radiator a couple time, once bad enough to have to get it repaired. The custom piece was MUCH more solid, and angled up to try to push the radiator up if I struck it again.
The end of my orange car time came at around six years and 97K miles. The car acquired an electrical gremlin. You can read the details in another post. Several other folks on the forum have had similar issues, just a Vette thing that might happen to random cars. And mine did have lots of miles. Two months, three shops, and lots of my own attempts, and I finally gave up. But I still loved the combination I had built, and I wanted to keep it. So, after looking at $90K for a new ZO6 vert, as well as several other possibilities, I decided to track down another 2009 base vert. That took a couple weeks. AO was impossible to find, and so I settled for a low miles Arctic White with 3LT trim and the butterfly exhaust. Spent about $7K switching everything over between the cars, turning the white one into a beast, and returning the orange one to stock. During the midst of the work, a burnt wire was found under a header of the orange one.
This was fixed, and the gremlin was gone. Oh well, that’s the way it goes.As I’m now in the Houston area, GForce did the tune on both cars. The white one, now using the meth, dyno’ed right at 600. I sold the orange one, and ended up out about $30K, to lose about 75K miles. That deal works for me, especially compared to the $90K for a new ZO6. Oh, I know I’m missing some upgrades, but I’ll bear up for now. And maybe add a forged engine sometime in the future.
And I am once again REALLY enjoying my ride. I still need to get back up to Bonneville, maybe this year, maybe next. And I haven’t had a chance to get on MSR-H yet, that should be fun. Re my personal choices, there are lots of ways to deal with the various issues, these just worked for me.
Story of the day.
The following users liked this post:
IMXCITD (04-13-2016)
08-04-2015, 05:29 PM
#5
Pro
Thread Starter
Oh for sure! No offense to ZR1 owners, they are wonderful cars. But I saved a boatload of money going my own route, and have a car that stays on the ground, with fewer cooling issues. Though the dry sump and forged engine would be nice . . .
08-05-2015, 08:37 AM
#7
Burning Brakes
Great read.
08-05-2015, 05:06 PM
#10
Le Mans Master
that was a great read and sounds like little gremlins that came up for my setup along the way 
I've always done basic modifications to most of the cars I've owned. Going for a whole supercharger, meth, etc. etc. etc. was a new game for me. Didn't realize that motto holds true..."the more you change the more stuff that goes wrong"
I'm at that phase of your story where you mention cooling issues and I'm thinking radiator and oil cooler coming down the pipe.
I've always done basic modifications to most of the cars I've owned. Going for a whole supercharger, meth, etc. etc. etc. was a new game for me. Didn't realize that motto holds true..."the more you change the more stuff that goes wrong"
I'm at that phase of your story where you mention cooling issues and I'm thinking radiator and oil cooler coming down the pipe.
08-05-2015, 06:30 PM
#11
Drifting
Definitely a good read. I myself am going through heat issues and have a nice brushless fan awaiting install. I'm also looking into hacking out one of my fog lights to use as an oil cooler vent and installing a screw on sandwich plate oil cooler system that bypasses when the oil is cold but hits the cooler when hot.
As for lift I find that interesting. My base C6 did feel a little floaty in touring mode (F55) but felt very planted at 185 mph in sport.
As for lift I find that interesting. My base C6 did feel a little floaty in touring mode (F55) but felt very planted at 185 mph in sport.
08-07-2015, 10:10 AM
#16
08-17-2015, 04:36 PM
#17
Pro
Thread Starter
I was out of town last weekend, taking the younger one off to college. I'll be heading back up Dallas way this upcoming weekend. Got a few buddies who need a ride . . .
08-17-2015, 06:26 PM
#18
What ive learned is the mod bug never stops!! Lol
08-17-2015, 09:18 PM
#19
Melting Slicks
Member Since: Mar 2007
Location: Santa Barbara CA
Posts: 2,391
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23 Posts
What I've learned over the years is that moderation (along with smart, educated decisions) is the key to making these things fun and reliable.
This really goes for modifying any car, though. My daily driver makes ~50% more RWHP and ~70% more RWTQ than stock, but is really no less comfortable or reliable. When done right, everything can still work the way it should.
This really goes for modifying any car, though. My daily driver makes ~50% more RWHP and ~70% more RWTQ than stock, but is really no less comfortable or reliable. When done right, everything can still work the way it should.
08-17-2015, 09:35 PM
#20
Burning Brakes
Why was the Amsoil a better choice over the Mobal1? I'm running boost as well and would like any thing that helps save it from drinking any oil or pushing any oil.