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Thought I'd throw this out there...ever since selling my turbo Buick, I've got the itch to get into forced induction again. I'll admit, boost is like crack....you get your first taste, then you want some more.
Anyways I've considered throwing a supercharger on my 69 Nova's 350 small block, but I don't know if I'd get the same effect as my turbo car did....or if it would be better....or worse....I don't know if I want to go turbo again since I'd have to custom build the headers for it, plumb oil lines, etc. I'm more after a bolt-on-and-go deal.
I've not driven a car with a s/c before...I'm sorta wondering how they compare to a turbo in terms of neck snapping acceleration...?
you don't need to have custom headers made. There are kits out there that are basically bolt and go for your application. My friend just finished his Nova last spring and seeing as how his v8 was just as fast as my turbo 4, he needed more. So we researched into turboing it because that's what I had experience in, and because I personally like turbo's more than superchargers. It's actually not all too difficult to turbo a SBC powered nova.
you don't need to have custom headers made. There are kits out there that are basically bolt and go for your application. My friend just finished his Nova last spring and seeing as how his v8 was just as fast as my turbo 4, he needed more. So we researched into turboing it because that's what I had experience in, and because I personally like turbo's more than superchargers. It's actually not all too difficult to turbo a SBC powered nova.
Are there intercooler kits for that platform too? If you can get an exhaust manifold (preferably cast for durability) and intercooler kits that are made to fit this application without having to farm out custom work to a shop it would be a relatively simple deal. How do you go about tuning?
Are there intercooler kits for that platform too? If you can get an exhaust manifold (preferably cast for durability) and intercooler kits that are made to fit this application without having to farm out custom work to a shop it would be a relatively simple deal. How do you go about tuning?
We didn't get that far. We are more so the DIY people so as far as bolt and go 100% not sure, But i'd imagine that there is something out there. We just mainly needed to find some headers that would be able to work with a turbo. We were going to piece together our own Intercooler plumbing if we couldn't find something that would work.
There has to be SOMETHING though, as a SBC is an extremely commonplace engine to work with. It might not be Nova specific, but honestly, how much different were those cars back in the day to where the routing wouldn't be interchangable. Also, with one of those piece it together yourself IC kits, you'll have more than enough piping to fab your own with some couplers.
Tuning though, I had a tuner that would tune anything. You gave him the application and he would tell you what to do and he'd tune it. But I would just imagine you would take it to a shop and have them tune it for you just like any other car. And being carbuerated, (i'm probably so far off here) isn't there no tuning involved as the amount of fuel being delivered is derived on how much air flow there is so that no matter what the proper amount of fuel is delivered?
We didn't get that far. We are more so the DIY people so as far as bolt and go 100% not sure, But i'd imagine that there is something out there. We just mainly needed to find some headers that would be able to work with a turbo. We were going to piece together our own Intercooler plumbing if we couldn't find something that would work.
There has to be SOMETHING though, as a SBC is an extremely commonplace engine to work with. It might not be Nova specific, but honestly, how much different were those cars back in the day to where the routing wouldn't be interchangable. Also, with one of those piece it together yourself IC kits, you'll have more than enough piping to fab your own with some couplers.
Tuning though, I had a tuner that would tune anything. You gave him the application and he would tell you what to do and he'd tune it. But I would just imagine you would take it to a shop and have them tune it for you just like any other car. And being carbuerated, (i'm probably so far off here) isn't there no tuning involved as the amount of fuel being delivered is derived on how much air flow there is so that no matter what the proper amount of fuel is delivered?
I know with my car, I went with vehicle specific intercooler piping kit because clearances between many of the components are pretty tight and I really didn't feel like buying a bunch of mixed piping and getting something that kind of worked (my kit only has four separate pieces and the cold side sits centimeters from an alternator pulley). With the older classics I know there is probably a lot more room to work with so fabbing something up yourself with piping and couplers might be a lot easier.
With regards to tuning carbureted cars for forced induction....I don't know. I understand this is a bit of a lost art lol. I guess that because a turbocharger/supercharger will force more air into the carburetor, it will naturally draw additional fuel through the carb (due to vacuum) although I can't see how you would lean out or richen certain rpm ranges since you don't have direct control over fuel.
I know with my modern engine management, I set specific fuel injector duty cycle values based on a specific RPM and MAF value which is a measure of air flow. It's not too difficult because I effectively look at my MAF value at a specific RPM which equates to a specific boost figure, and then look at my AFR's to see if I'm rich or lean and then either add or remove fuel to reach an ideal AFR.
Last edited by iTsLiKeAnEgG; 05-17-2013 at 03:47 PM..
Boost is controlled first by the physical capability of the compressor. That's really a mechanical issue - rpm, size and shape of the vanes, etc. The actual boost is controlled by a wastegate or valve. There is nothing different about raising the boost pressure of a turbo vs. a SC.
A turbo can't just be made to spin faster. You could change the turbo to a different one.
A SC could be made to spin faster with a different pulley.
But boost levels can be changed for either through the wastegate.
Uh, no. Most supercharged cars don't even have a wastegate. I have a twin 18g 911 Turbo, I know a little about what I'm talking about.
There is a world of difference between the max boost made with a turbo vs a supercharger. A turbo's max boost is limited by the compressor AND the turbine, and simply by the volume of air the exhaust can flow. You can stick the largest turbo in the world on a car, capable of making 1000+ horsepower... but if the engine is too small to even begin to be able to use it in its efficiency range, it's worthless.
Superchargers have pulleys, and to change the max boost you HAVE to change the pulley. No exceptions. Wastegates have only recently been installed on supercharged applications, and it's still different than a turbo, because you can't increase boost past the limits of the pulley you've chosen. They're used when you want to fine tune the car by running a 15 psi pulley for example, but then using the wastegate to only run 12 psi.
For a turbo, you can run open wastegates and most turbos can hit 30 psi or more, or simply getting a flash tune to run more psi. There's a lot more flexibility with a turbo setup.
Finally, a turbo and a SC can be made to spin faster... it's called pushing the gas pedal down farther.
Twin 18g's on a 911 should be wild and still retain decent spool. I'm pushing my single TD05-20G with a 2.0L 4 banger and even that makes for a wild ride when boost hits. Initial power delivery feels like an exponential function lol.
you don't need to have custom headers made. There are kits out there that are basically bolt and go for your application. My friend just finished his Nova last spring and seeing as how his v8 was just as fast as my turbo 4, he needed more. So we researched into turboing it because that's what I had experience in, and because I personally like turbo's more than superchargers. It's actually not all too difficult to turbo a SBC powered nova.
Can you please provide me a list of what parts you all used to make this work? And what year Nova?
Quote:
Originally Posted by DELL37
Per lbs of boost a turbo car will be more efficient and make more power. I've owned a couple of factory supercharged and turbo cars as well as built my own setups. While some people will tell you that turbos are "free" power that isn't exactly true as there is "some" loss due to back pressure but this is minimal.
Here's is what I found out swapping a blower for a turbo kit without making any additional changes to the car. After playing with an 04 Cobra for a couple of yrs I had a car that made 522HP and 564 lbs to the tires. It had been dynoed a number of times and these were the best numbers. Boost was right at 15lbs. It had headers, exhaust, cams, a tune etc etc. It was fun but I knew there was more. Being a turbo guy my entire life I knew something big was missing.
I met John Urist in the pits at the drag strip one day and started talking about his kit for the 04 Cobra. I made the call the following week and had a kit at my house in a month. I did the install at home and drove the car for a couple of days very easy to make sure I didn't have any leaks etc. I scheduled a time to have a local shop do a tune and dyno time. Putting a very safe tune in the car the first pull was at 5 lbs of boost. The car responded with around 350 at the tire. Boost was bumped to 11lbs and the car laid down 535hp and 602 lbs tq. For those that are doing the math. That's more power and torque than it made with the blower with 4 lbs LESS boost. We bumped the boost one last time back to the same 15lbs run on the blower and the car responded with 684hp and 773lbs tq. The shop recommended turning it down as that was approaching the limit of the stock parts and I did plan to drive it pretty hard. We turned it down to 12 lbs and left it alone
For the record that's 162hp and 209 lbs tq MORE with the turbo than with the blower at the same boost level. Both setups were tuned by the same shop on the same dyno and no other changes were made to the car.
Turbo cars can be a real pain the butt to build and work on but there isn't a comparison when it comes to power.
One last thing.. People like to talk about turbo lag or waiting for the boost to hit.. That was an issue years ago and could be a problem today IF you choose a turbo that is too large for your application. No point in putting a pair of 88's on the car if all you want to make is 600hp...
I've put together a number of old SBC combo's and the Nova is a very easy platform to build on. IF your 350 is basically stock I'd recommend going pretty small on the turbo. A single 62-67mm T04 unit with a .81 exhaust A/R will give you almost instant boost. Keep the boost at 5-6lbs and it should make well north of 450HP with a mild cam and intake. The key will be to clean up the heads and get a good exhaust system after the turbo.
If you seriously want to do a turbo SBC let me know. I can give you part numbers and dyno results for some of the cars i've built over the years.
All this talk about max potential HP and Tq is great, but no one here is running anything at the limits of available tech. So suggesting that one FI setup is inherently better than another is really an exercise in theory. A blower setup can be put on and perform as well as a turbo, and vice versa. If turbos were always better, why do the fastest dragsters all use blowers? If blowers were always better, why do most FI street cars use turbos? Since most of you apparently only drive in a straight line (a Porsche on a drag strip is a waste ) you wouldn't understand what it's like when a turbo spools up before the apex of that thing called a turn. Blowers are linear and more predictable, and generally give more power in the lower RPM range. Then again, why does Porsche use turbos?
All this talk about max potential HP and Tq is great, but no one here is running anything at the limits of available tech. So suggesting that one FI setup is inherently better than another is really an exercise in theory. A blower setup can be put on and perform as well as a turbo, and vice versa. If turbos were always better, why do the fastest dragsters all use blowers? If blowers were always better, why do most FI street cars use turbos? Since most of you apparently only drive in a straight line (a Porsche on a drag strip is a waste ) you wouldn't understand what it's like when a turbo spools up before the apex of that thing called a turn. Blowers are linear and more predictable, and generally give more power in the lower RPM range. Then again, why does Porsche use turbos?
It's not theory, turbos ARE more efficient. You're using spent exhaust gases whose energy would be lost simply as heat, to be used again for forced induction. A supercharger on the other hand, doesn't recoup any energy lost by heat, and even has parasitic losses from driving the pulley.
Dragsters use blowers because of the instant power, there is no turbo lag. When you're running the 1/4 in less than 5 seconds, even hundredths of a second count. Fuel use (and efficiency) is also not much of a consideration for dragsters.
Porsche uses turbos because it's a better way to make a 3.6 or 3.8 liter engine perform like a much larger NA motor. For them, it does come down to efficiency. Stock Porsche turbos actually aren't that big, I'd argue they are a bit on the small side, which gives them extremely fast spool up. The latest turbos running VTG turbos are even more efficient, and have very little lag. With short gearing, any lag is basically unnoticeable.
(For the record, that's not my car on the drag strip, I track mine. The turbos they had in that car is what is in mine now.)
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) you wouldn't understand what it's like when a turbo spools up before the apex of that thing called a turn. Blowers are linear and more predictable, and generally give more power in the lower RPM range. Then again, why does Porsche use turbos?
