Centrifugal Blower vs Turbo (Twin Turbo vs Single)
#81
Melting Slicks
Budget controls "best setup". The more limited budget, the more you start having to make your own parts, you need a welder, fab shop, etc and the cost will have this sort of parabolic effect where it costs even more as you try to do more things yourself the right way with expensive tools and equipment factored in. Imagine having to buy a whole machine shop just to tool 1 engine over for 1 car, that would be far more expensive than buying a bunch of built engines done somewhere else. But then the where else becomes a variable all of it's own with it's own probability statistics for success that are now out of your control. So budget in this perspective reflects build control: How much control do I want or need to have over each aspect.
I will skip to the good stuff. Lets say you need 100% control, but also combined with low budget. It means you cannot buy your own machine shop to turn out an engine, and having 100% control means you cannot buy a built engine either. That limits us instantly to SBE variety so we start from there: find the best stock engine for the build that meets the budget. If engine budget is $500 you go for the 5.3L truck engine. If you have more you try to get an aluminum variety. Most stock engines stop between 800-1000rwhp so I wouldn't be thinkin about much more than 700 to the tires in a daily driver with some kind of budget SBE setup. Once you figure that part out the rest is easy: pick a cover that flows ~80lb/min and put a mild cam (228* @ .050 with less than .600 lift) and off you go with whatever you create, wherever you decide to put it.
I will skip to the good stuff. Lets say you need 100% control, but also combined with low budget. It means you cannot buy your own machine shop to turn out an engine, and having 100% control means you cannot buy a built engine either. That limits us instantly to SBE variety so we start from there: find the best stock engine for the build that meets the budget. If engine budget is $500 you go for the 5.3L truck engine. If you have more you try to get an aluminum variety. Most stock engines stop between 800-1000rwhp so I wouldn't be thinkin about much more than 700 to the tires in a daily driver with some kind of budget SBE setup. Once you figure that part out the rest is easy: pick a cover that flows ~80lb/min and put a mild cam (228* @ .050 with less than .600 lift) and off you go with whatever you create, wherever you decide to put it.
#82
Melting Slicks
"Lag" gets a lot of bad rap that we need to put into perspective. Most setups feature 'oversized' turbos because they are racing the vehicle in question. If you flow to around half of the compressor map, you are sitting right near the center island (a little to the right is...) Use a 'matchbot' to see where the engine combo lands, for example here is my 5.3 with the turbo I picked:
http://www.turbos.borgwarner.com/go/05M2G7
If I was racing the car this turbo would be terrible because it flows right out of the center island and off the map to the right almost immediately once it gets some boost in it. However, this is how the OEM typically size a turbo: peak torque of the engine is near the center island and the compressor runs right of it as it nears redline, falling off the map to the right. This is what happens when we size the turbo "just large enough to make the total desired power: 80lb/min giving us ~800 horsepower". Why the OEM does this is for a couple simple reasons: the first being that now the turbo's wheels weight is minimal and it will spool as fast as possible. The second is now the turbo will be most efficient during engine peak torque, adding to the 'surge' of torque midrange (often turbos are added to 4-cylinder and 6-cylinder engines which spend more time there in daily driver applications) and ensuring an efficient compressor when compression pressure is highest (peak torque region). There may be other reasons but we can take those that we already have and go to the bank: if you want the vehicle to drive like that, with powerful mid-range, fast as possible spooling, almost like an N/A engine quality, you would size the turbo the same way.
Lets look at racing again to tie this up. In racing the engine will not spend any time in mid-range. Even spooling up we would use nitrous and so forth to get it going and a large racing converter to blow through the mid-range and get to the peak power. So we size the turbo for that: we make sure it runs into it's center island during peak power, instead of peak torque like we wanted above for the street car. This way the compressor is most efficient during peak power region. It has "too much to give" more than we want. If you wanted 1000 to the tire in a racing setup you would buy a 1400-1600hp turbo and not use the right most portion of the map, this is how you would set the matchbot to choose a turbo.
http://www.turbos.borgwarner.com/go/05M2G7
If I was racing the car this turbo would be terrible because it flows right out of the center island and off the map to the right almost immediately once it gets some boost in it. However, this is how the OEM typically size a turbo: peak torque of the engine is near the center island and the compressor runs right of it as it nears redline, falling off the map to the right. This is what happens when we size the turbo "just large enough to make the total desired power: 80lb/min giving us ~800 horsepower". Why the OEM does this is for a couple simple reasons: the first being that now the turbo's wheels weight is minimal and it will spool as fast as possible. The second is now the turbo will be most efficient during engine peak torque, adding to the 'surge' of torque midrange (often turbos are added to 4-cylinder and 6-cylinder engines which spend more time there in daily driver applications) and ensuring an efficient compressor when compression pressure is highest (peak torque region). There may be other reasons but we can take those that we already have and go to the bank: if you want the vehicle to drive like that, with powerful mid-range, fast as possible spooling, almost like an N/A engine quality, you would size the turbo the same way.
Lets look at racing again to tie this up. In racing the engine will not spend any time in mid-range. Even spooling up we would use nitrous and so forth to get it going and a large racing converter to blow through the mid-range and get to the peak power. So we size the turbo for that: we make sure it runs into it's center island during peak power, instead of peak torque like we wanted above for the street car. This way the compressor is most efficient during peak power region. It has "too much to give" more than we want. If you wanted 1000 to the tire in a racing setup you would buy a 1400-1600hp turbo and not use the right most portion of the map, this is how you would set the matchbot to choose a turbo.
#83
1000-whp target and less => Go with supercharger POS or Centri
1000+whp and more => Go with Turbochargers
If your personality is thirsty for more power and participating in drag racing with targets in mind that require more HP and power every time to compete,,, definitely the turbo is your love.
I don't have experience with turbos yet but I was very happy with Centri's reliability (except F2 was aggressive) in past years making from 700 to 1100whp ( & now moved to Twins turbos seeking 1800+hp, build in progress)
1000+whp and more => Go with Turbochargers
If your personality is thirsty for more power and participating in drag racing with targets in mind that require more HP and power every time to compete,,, definitely the turbo is your love.
I don't have experience with turbos yet but I was very happy with Centri's reliability (except F2 was aggressive) in past years making from 700 to 1100whp ( & now moved to Twins turbos seeking 1800+hp, build in progress)
Last edited by WHITE_SHARK; 08-13-2020 at 05:21 AM.
#84
Melting Slicks
1000-whp target and less => Go with supercharger POS or Centri
1000+whp and more => Go with Turbochargers
If your personality is thirsty for more power and participating in drag racing with targets in mind that require more HP and power every time to compete,,, definitely the turbo is your love.
I don't have experience with turbos yet but I was very happy with Centri's reliability (except F2 was aggressive) in past years making from 700 to 1100whp ( & now moved to Twins turbos seeking 1800+hp, build in progress)
1000+whp and more => Go with Turbochargers
If your personality is thirsty for more power and participating in drag racing with targets in mind that require more HP and power every time to compete,,, definitely the turbo is your love.
I don't have experience with turbos yet but I was very happy with Centri's reliability (except F2 was aggressive) in past years making from 700 to 1100whp ( & now moved to Twins turbos seeking 1800+hp, build in progress)