“… the greatest detractor from high performance is fear: fear that you are not prepared, fear that you are in over your head, fear that you are not worthy, and ultimately, fear of failure. If you can eliminate that fear—not through arrogance or just wishing difficulties away, but through hard work and preparation—you will put yourself in an incredibly powerful position to take on the challenges you face" - Pete Carroll.
1. b-b-b-but I thought Lag couldn't be shown on a dyno??
2. THIS is your 'obvious advantages of a SC over a TC'??
But you've admitted an improperly-designed SC system CAN result in Lag, but make no allowances that a PROPERLY designed Turbo system cannot eliminate lag? And I've also shown how SC systems are not 'on' all the time, too.Since it’s mechanically connected to the crankshaft, its “on” all the time, hence no lag
3. Define drivability? I've put up more than a couple dyno plots showing fairly smooth power delivery. I've DRIVEN turbo systems where the transition from vac to boost is seemless. It's a fallacy to imply 'all' turbo systems suffer drivability issues because the turbo cars you may have driven had them.
“… the greatest detractor from high performance is fear: fear that you are not prepared, fear that you are in over your head, fear that you are not worthy, and ultimately, fear of failure. If you can eliminate that fear—not through arrogance or just wishing difficulties away, but through hard work and preparation—you will put yourself in an incredibly powerful position to take on the challenges you face" - Pete Carroll.
1. It can’t. Are you now admitting same?
2. I admit that an improperly applied system can produce negative results. Whouda thunk? Perhaps a turbo can eliminate lag, but I haven’t seen it.
3. Drivability is the immediate and linear increase or decrease in power with a corresponding change in throttle position.
Last edited by glockmail; 07-03-2007 at 11:46 AM. Reason: refined definition
1. But the dyno SHOWS the 'lag'. The turbo begins spinning as soon as exhaust passes through it...it 'lags' until enough exhaust causes it to spin fast enough to produce usable boost.
2. But I've shown you dyno evidence of "no" or "so-small-as-to-be-no-Lag."
Here's just ONE example of a modern turbo system:
One moreBMW’s first U.S.-market gasoline turbo, a 3.0-liter blown six-cylinder, has two small IHI turbochargers that each pressurize three cylinders with a maximum of about nine psi of boost. Direct fuel injection, a first for a BMW gasoline turbo engine, helps to cool the intake charge and allows a high 10.5:1 compression ratio. The block is made from aluminum, not magnesium and aluminum as used in BMW’s naturally aspirated straight-sixes. Horsepower is 300 at 5600 rpm, and the peak torque of 300 pound-feet arrives at just 1400 rpm and hangs on until 5000 revs. We’ve driven the 335i, and if there’s any turbo lag, it’s infinitesimal.
3. You need to get out of the house and drive a modern designed turbo system. You'll be surprised....considering the boost pressures (15.6 psi at its peak), the revs come surprisingly lump-free. Mega-boost cars often have mega-abrupt transitions from boost off to boost on. (The Mazdaspeed 6 has a) steady, deliberate surge rather than a sudden whoosh
“… the greatest detractor from high performance is fear: fear that you are not prepared, fear that you are in over your head, fear that you are not worthy, and ultimately, fear of failure. If you can eliminate that fear—not through arrogance or just wishing difficulties away, but through hard work and preparation—you will put yourself in an incredibly powerful position to take on the challenges you face" - Pete Carroll.
The dyno can't show the lag as explained earlier; dynamic throttle position is not reported. The report about "infinitesimal" lag is a better indication. I am aware the BMW held off using turbos for a long time because of the lag issue. Apparently they did a nice job and should consult for Porshe.
My days of driving sports cars will need to wait until my kids are through college.
Of course it can show lag; I've shown you how. Are you saying you want to know how the turbo performs under every possible throttle position, by gear?
Sometimes I think you're just making up stuff for the sake of being difficult.
Porsche's turbo systems have even 'less.' Read up on cars today, Glock, and things such as DFI engines and Variable Vane turbos.
“… the greatest detractor from high performance is fear: fear that you are not prepared, fear that you are in over your head, fear that you are not worthy, and ultimately, fear of failure. If you can eliminate that fear—not through arrogance or just wishing difficulties away, but through hard work and preparation—you will put yourself in an incredibly powerful position to take on the challenges you face" - Pete Carroll.
You don't understand boost threshold vs. turbo lag.
The guy starts out in 4th or 5th gear...floors it...and waits for the exhaust to generate enough velocity and heat to get the turbo making boost. This happens VERY quickly - which shows the turbo does NOT take a lot to spool up. It's 'not laggy'. The dyno clearly shows that.
“… the greatest detractor from high performance is fear: fear that you are not prepared, fear that you are in over your head, fear that you are not worthy, and ultimately, fear of failure. If you can eliminate that fear—not through arrogance or just wishing difficulties away, but through hard work and preparation—you will put yourself in an incredibly powerful position to take on the challenges you face" - Pete Carroll.
“… the greatest detractor from high performance is fear: fear that you are not prepared, fear that you are in over your head, fear that you are not worthy, and ultimately, fear of failure. If you can eliminate that fear—not through arrogance or just wishing difficulties away, but through hard work and preparation—you will put yourself in an incredibly powerful position to take on the challenges you face" - Pete Carroll.
I think you've clearly shown that you don't know WTF you're talking about.
The dyno you describe isn't typical of the type that are used on automobiles. A DynoJet, for instance, applies a load as the vehicle comes up to speed. Usually this is done in 4th gear (1:1). It's a continuous measurement.
Go drive a few modern turbocharged vehicles and then get back to us. If you'd like a list of said vehicles, feel free to ask.
It's easier to buy gear than talent.
www.google.com Wikipedia.org works too. Bring your level of knowledge to 'within the past 20 years'; that'd be a great starting point.
The chart shows Horsepower and Torque. Torque is measured and horsepower calculated from torque. One can see the WAY the engine makes power by looking at the chart. It's VERY simply stuff now Glock; but if you refuse to learn there's no point in going on beating myself up trying to teach you.
“… the greatest detractor from high performance is fear: fear that you are not prepared, fear that you are in over your head, fear that you are not worthy, and ultimately, fear of failure. If you can eliminate that fear—not through arrogance or just wishing difficulties away, but through hard work and preparation—you will put yourself in an incredibly powerful position to take on the challenges you face" - Pete Carroll.