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I ran against one of these yesterday at a 1/2 mile runway event. He got a great launch and was probably about 4 car lengths ahead of me for a bit (stinking runway paint at the starting line!). I believe i got him by about a fender at the very end though. He said it got too hot toward the end of the run. Ill check to see if i caught this run on the pdr.
Nice kit and can make a ton of power if you build a block that can take it. The centrifugal sc kits are just so much cheaper, this is going to be a tough sell unless more guys start swapping in built engines.
Nice guy and great looking car. He did say this kit was kind of their prototype kits and had been on and off the car several times. It was definitely going to get recoated soon
I ran against one of these yesterday at a 1/2 mile runway event. He got a great launch and was probably about 4 car lengths ahead of me for a bit (stinking runway paint at the starting line!). I believe i got him by about a fender at the very end though. He said it got too hot toward the end of the run. Ill check to see if i caught this run on the pdr.
Nice kit and can make a ton of power if you build a block that can take it. The centrifugal sc kits are just so much cheaper, this is going to be a tough sell unless more guys start swapping in built engines.
Nice guy and great looking car. He did say this kit was kind of their prototype kits and had been on and off the car several times. It was definitely going to get recoated soon
Either way a tough sell. I would not want that mess under my hood.
Also for the price of these twin kits you can get a supercharger AND build the engine.
Turbos and tight Corvette engine compartments are a tough combination....
Look at the pic., above. The air intake is compromised. It is sucking hot air from behind the radiator... For 700hp, the air filters are a huge restriction! They are only good for a lawn-mower!
Altitude correction factors do not work for turbos on a dyno, since turbos compensate for altitude, themselves. They do not compensate 100%, but the naturally aspirated correction does not apply.
Anothe problem is the size of the Corvette motor. 500hp is possible from 2L 4-cyliner, 850hp from 3.6L 6-cylinder, 5 to 7L V8 should make 1200+hp to make it interesting.....
My turbo recipe:
1. 304 stainless is for kids. It is what spoons are made of. It is inexpensive, but at high temperatures, it will corrode and scale. 321 or (more rare) 347 stainless was made for high temperature exhaust. There is no reason to use thick schedule 10 plumbing pipe (304 is used in food processing). 16 gauge is plenty with 321. Inconel is even better, 0.030 (yes paper thin) tube will be stronger than 304 or 321 or titanium at turbo inlet temperature. Inconel will not scale or dull. It will stay shiny, even wrapped in insulation and running very high exhaust temperatures. It is expensive. 304 can be used after the turbine, where the temperatures are much lower.... BTW, Inconel is used by F1, usually in 0.020 thickness.
2. Use Borg-Warner EFR turbo. It has BOV and waste-gate built in. At 15 to 20 psi boost levels both work well and take much less space.
3. Use one turbo with split turbine inlet. Just like Indy cars. They have a choice of one large turbo to 2 small ones. 2 small ones may make plumbing with 2 intercoolers and 2 banks of cylinders easier. On the other hand, since Corvette motors have flat cranks, plumbing can be OK. Big motor should be able to spool up 1 turbo well. Also with modern materials, like the EFR, the spool is much better.
4. Garrett and Precision have good turbos. They lack feature (2) and (3). Some of them have built-in waste-gates but they are not effective. Also the split-turbine (usually T4) housing on Garrett and Precision is a very different design that BW EFR. BW EFR is much better for a flat crank V8 or V6.
My design just saved 3 to 4k. Inconel piping would add $500 to $1000 back.
Good test for a turbo car is a lapping session for an hour. 1/4 mile takes under 10 seconds. 1 mile take 20 to 30. City driving in stop-and-go traffic does not really use the turbo, but does check for heat accumulation under the hood, with only the rad fan to get rid of it. Lapping is 30 minutes to 1 hour.
Garett seems to have sold the patterns and manufacturing rights for their old turbos to the Chinese. Maybe they just copied them. They are cheap. There is lots on e-bay. The are probably designed to diesel trucks... None will last on a gas motor.
Eh. Still not cost effective. 700+rwhp can be had for only $5k with a centri supercharger system and tons of tuning opportunities. Nothing really adds up with a turbo and inconel is very expensive and requires experience to use and that experience costs money.
I agree with the main point. On a large displacement motor, there is plenty of power, already.A smaller motor with a small added weight penalty of a turbo like a 3.5L can make more power that a 6L V8. There are many examples out there already. To me a 'break-even' point for any supercharged a 6L V8 is 1000+hp.
Inconel is very easy to weld, similar to 304 or 321. I recall, so not sure, but when welding 321, Inconel rod is used. The weld is much stronger than the base part. It is expensive, but can be made very light and last much longer and not suffer any problems. Maybe the expense is justified. Inconel stays shiny with reflective surface, even under a thermal wrap e.g. after repeated 1800F exposure. It has a saphire sheen to it. I have pics.
Then there is a traditional turbo vs. supercharger debate. Maybe that should be a separate thread. consider some points:
1. Turbo can and will make more power, if the internals will hold it or for same internal mods. Supercharger takes 150hp off the crank. Turbo has some back-pressure, but not 150hp worth. Turbo can run higher boost more efficiently.
2. There are lots of available supercharger kits out there. It is a simpler system.
3. Intercooling is same. Superchager provides simpler packaging.
4. Supercharger is heavier.
5. Modern superchargers are closer to whipple design so more efficient.
6. A very good single turbo system could be built for a Corvette. it would be cost-competitive.
7. why 6, given what we have, already.
8. With internal mods a V8 can run 1200-1500hp on 20lbs boost with no issues. Do we need that?
Consider the following production, street cars:
MB CLA45 375hp from 2L
Ford GT 600hp from 3.5L
Caddy ATS, the V6 has a lot left on the table
Alfa Romeo 4C with 250hp from 1.7L
So single turbo V8 is 750hp in light street trim without breaking a sweat... Then the sky and strength of head bolts is the limit.
What about trany and the diff and the 'nut behind the wheel'. All of those will break( the car) first.
GM probably got upstaged by the GT vs. C8...
Anton
Originally Posted by NinjamanZ51
Eh. Still not cost effective. 700+rwhp can be had for only $5k with a centri supercharger system and tons of tuning opportunities. Nothing really adds up with a turbo and inconel is very expensive and requires experience to use and that experience costs money.
You make some valid points but I do not think a turbo is the best option for most enthusiasts using this particular vehicle. Perhaps a rear mount system would prove more efficient for heat displacement but then you have tubing to run to the front of the car and subsequent boost lag albeit relatively minor. Fortunately, that's where displacement comes in handy! Additionally, running a rear mount setup will eliminate the need for inconel or any fancy alloy. Is it cost efficient? Maybe. Unfortunately, it adds more parts to go wrong and for the average Corvette enthusiast, that may not bode well.
Anyway, we don't need to go into a turbo vs. supercharger debate. There's plenty of data for and against either application and we don't need to beat a dead horse. We all know a turbo is exhaust driven and a supercharger is powered by an engine's accessory belt drive. There are pros and cons to both and so forth.
Have fun building your custom system!
Originally Posted by ageshelin
I agree with the main point. On a large displacement motor, there is plenty of power, already.A smaller motor with a small added weight penalty of a turbo like a 3.5L can make more power that a 6L V8. There are many examples out there already. To me a 'break-even' point for any supercharged a 6L V8 is 1000+hp.
Inconel is very easy to weld, similar to 304 or 321. I recall, so not sure, but when welding 321, Inconel rod is used. The weld is much stronger than the base part. It is expensive, but can be made very light and last much longer and not suffer any problems. Maybe the expense is justified. Inconel stays shiny with reflective surface, even under a thermal wrap e.g. after repeated 1800F exposure. It has a saphire sheen to it. I have pics.
Then there is a traditional turbo vs. supercharger debate. Maybe that should be a separate thread. consider some points:
1. Turbo can and will make more power, if the internals will hold it or for same internal mods. Supercharger takes 150hp off the crank. Turbo has some back-pressure, but not 150hp worth. Turbo can run higher boost more efficiently.
2. There are lots of available supercharger kits out there. It is a simpler system.
3. Intercooling is same. Superchager provides simpler packaging.
4. Supercharger is heavier.
5. Modern superchargers are closer to whipple design so more efficient.
6. A very good single turbo system could be built for a Corvette. it would be cost-competitive.
7. why 6, given what we have, already.
8. With internal mods a V8 can run 1200-1500hp on 20lbs boost with no issues. Do we need that?
Consider the following production, street cars:
MB CLA45 375hp from 2L
Ford GT 600hp from 3.5L
Caddy ATS, the V6 has a lot left on the table
Alfa Romeo 4C with 250hp from 1.7L
So single turbo V8 is 750hp in light street trim without breaking a sweat... Then the sky and strength of head bolts is the limit.
What about trany and the diff and the 'nut behind the wheel'. All of those will break( the car) first.
I do not speak of any fantasy turbo system. I built a few. I tuned some myself. I raced cars with them. I have done and felt what it works like in a road race car. I know which parts it breaks first.
I do not want to hijack the thread.
If anyone is interested in pics and details, please PM.
Anton
P.S. I am not trying or have anything to sell.
Originally Posted by NinjamanZ51
You make some valid points but I do not think a turbo is the best option for most enthusiasts using this particular vehicle. Perhaps a rear mount system would prove more efficient for heat displacement but then you have tubing to run to the front of the car and subsequent boost lag albeit relatively minor. Fortunately, that's where displacement comes in handy! Additionally, running a rear mount setup will eliminate the need for inconel or any fancy alloy. Is it cost efficient? Maybe. Unfortunately, it adds more parts to go wrong and for the average Corvette enthusiast, that may not bode well.
Anyway, we don't need to go into a turbo vs. supercharger debate. There's plenty of data for and against either application and we don't need to beat a dead horse. We all know a turbo is exhaust driven and a supercharger is powered by an engine's accessory belt drive. There are pros and cons to both and so forth.
I miss having a turbo on my old car. I was able to adjust boost according to what fuel map I was running. I had pump gas only, pump gas meth, and race fuel map. I used an electronic boost controller to add or subtract boost based on the map I was running. Boost by gear was also nice. They can also adjust how much to ramp up boost by rpms if you're having traction issues.
Reading through all this debate I have to laugh. Since we're in production of a C7 TT kit, technically I'm a competitor to PTS, yet when I look at this kit I'm impressed in that it looks like a well thought out and designed kit. Anyone can sit in the passenger seat and critique a kit, but until you're in the position of designing a mass production kit, that's affordable, and actually works......
I've designed one for this platform, and there isn't alot of room in there. Just the fact that they have a working product is in itself an accomplishment.
A couple things to note:
1. Yes, a SC kit is cheaper. This has generally always been the case, so why the surprise? The fact is, a TT makes better mid range tq than a centrifugal, and way better top end than a PD. In fact pound for pound a turbo setup will always make more power simply due to the inherent pumping losses attributed with the SC. It's really an entirely different animal. If you're really simply trying to compare HP per dollar, nitrous.... $550 kit you can have as much power as you want! But it's different, and at the end of the day so is turbo vs sc. Yes, they're both FI, but they're entirely different animals. Both have their pro's and both have their con's.
2. Single vs Twin is a moot point. It's like asking do you want a gallon of milk or two half gallons? It's the same thing. And with proper turbo sizing you can accomplish faster spool or better power with either. If you really want to split hairs, TT's are slightly more efficient because of the reduced heat/pressure loss associated with a cross over pipe, but it's so negligible it's not worth talking about. And looking at things from a mass production standpoint where labor is the most expensive component, the build cost would roughly be the same anyways.
3. Some of the things brought into question like the filters behind the radiator is simply insignificant. You're super heating the air by compressing it through the turbo anyways, then cooling it with the IC. So the initial start temp really doesn't play that much of a roll. Yes, this has been tested. Hence why most FI car's a cold air intake makes no real difference over a simple short ram....
By all means, I'm not trying to criticize you, in fact I would encourage you. If you can make an inconel turbo kit using EFR turbos, for $2-3K less than this one on a mass production level while still maintaining a profit margin to cover your overhead costs and feed your family, go for it! I along with the rest of the world would LOVE to see this!
Reading through all this debate I have to laugh. Since we're in production of a C7 TT kit, technically I'm a competitor to PTS, yet when I look at this kit I'm impressed in that it looks like a well thought out and designed kit. Anyone can sit in the passenger seat and critique a kit, but until you're in the position of designing a mass production kit, that's affordable, and actually works......
I've designed one for this platform, and there isn't alot of room in there. Just the fact that they have a working product is in itself an accomplishment.
A couple things to note:
1. Yes, a SC kit is cheaper. This has generally always been the case, so why the surprise? The fact is, a TT makes better mid range tq than a centrifugal, and way better top end than a PD. In fact pound for pound a turbo setup will always make more power simply due to the inherent pumping losses attributed with the SC. It's really an entirely different animal. If you're really simply trying to compare HP per dollar, nitrous.... $550 kit you can have as much power as you want! But it's different, and at the end of the day so is turbo vs sc. Yes, they're both FI, but they're entirely different animals. Both have their pro's and both have their con's.
2. Single vs Twin is a moot point. It's like asking do you want a gallon of milk or two half gallons? It's the same thing. And with proper turbo sizing you can accomplish faster spool or better power with either. If you really want to split hairs, TT's are slightly more efficient because of the reduced heat/pressure loss associated with a cross over pipe, but it's so negligible it's not worth talking about. And looking at things from a mass production standpoint where labor is the most expensive component, the build cost would roughly be the same anyways.
3. Some of the things brought into question like the filters behind the radiator is simply insignificant. You're super heating the air by compressing it through the turbo anyways, then cooling it with the IC. So the initial start temp really doesn't play that much of a roll. Yes, this has been tested. Hence why most FI car's a cold air intake makes no real difference over a simple short ram....
By all means, I'm not trying to criticize you, in fact I would encourage you. If you can make an inconel turbo kit using EFR turbos, for $2-3K less than this one on a mass production level while still maintaining a profit margin to cover your overhead costs and feed your family, go for it! I along with the rest of the world would LOVE to see this!
Nick, awesome kit, keep up the good work!
CK
So do you have a kit available? Im located in colorado and trying to get something performance wise for my C7. Thanks
This is a brand new account and has only commented on this post.
I actually have PTS building my c7 and am getting one of their turbo kits.
They are great people to work with and have made me exceptionally happy overall with their flexibility as I have changed my setup multiple times from the original kit to large turbos to a full engine build to even larger turbos to changing it completely to a big single turbo and so on lol. They are great people who do amazing work, and I highly recommend.
11-12-2015, 07:12 AM
