wakeech

hey guys, y'all know that i know a thing or two about most movey-bits on a car, but one thing about which i don't know as much as i want is the all-mighty turbo system...
i know the mechanical and functional basics, but i wanna know at-least-as-much-but-probably-lots-more about turbos than i do about wankels... especially about impeller design... i want nitty-gritty, hard numbers and theory, no pictures necessary (but who doesn't like pictures, right?? )

books, websites (couldn't find much i didn't know already), anything at all... just point the way please...

...i wanna know more than you, just help a brother out.

Dazz... Buger... Eccles... babylou... Grimace... smart people, racy people... i know you're out there, lurking...

Strider

I don't know if you get Turbo Magazine there in the nother, but I would give it a shot. The past few issues have been really helpful with my learning what all the parts/theories/technicallities are. I believe it's an ongoing article that they keep adding to each month. If you don't I can scan and post them somewhere.

Strider-

wakeech

i've read what they have online: strictly unimpressive... is the publication any better??

Strider

I'll check it out then get back to you. And I'm not saying they are the know it all or anything, but they do give a good understanding of how everything works. But knowing you... you'll want more than that :D

Strider-

mrWankel

check out http://auto.howstuffworks.com/turbo.htm

Dave

Supercharger

Why turbo is not the way to go…

Quote from May issue of CARandDRIVER:

“Turbos, as in Audi’s previous S4, can be plenty fast, but they never have the no-waiting torque, nor do they ramp up in a trusty way as you dip into the power. And they never have the magic burble, either.

This new S4 gets the company’s 4163cc, five-valves-per-cylinder, all-aluminum V-8 rated at 340 horsepower at 7000 rpm. It has a bottomless reservoir of torque - adrenaline delivery, no waiting - and great flexibility. Nothing loafs along like a substantial V-8. This one, Audi says, is no heavier than the twin-turbo 2.7 V-6 of the previous S4.”

Audi 4.2-liter V8: 340 hp / 302 lb-ft

The 4.2-litre V8 engine is also impressive thanks to its compact design. Its dimensions - especially the length of only 464 mm (18.3 in.) - enable installation for the first time in an extremely slim engine compartment.

To make this compact feature possible, Audi's engine developers installed a chain drive for camshafts and ancillaries on the engine output side, making it possible to reduce the length by no less than 52 mm (2 in.).

The entire V8, with a gross weight of just 195 kg (430 lb), is just as light as its predecessor in the previous S4, a twin-turbo 2.7-litre V6 engine, resulting in major benefits for the weight balance and handling characteristics.

MaRX8

But they sound so cool.... grew up in my parents Saab 900 Turbo.

Sputnik

That's comparing two different engines available in the same car, not turbocharging in general.

And what the heck is a "flexible" engine?

---jps

wakeech

Supercharger, i'm not so certain that some of these automotive "authorities" really know what they're talking about in absolute engineering terms: it may be better (as far as fuel consumption and reliability goes) for a road car to do it all-motor, but there are may benefits to having a forced induction system, the most superior of which (i believe) is the turbocharging system... as far as RAW performance goes, they're pretty tough to beat.

continuation

yeah, to compete with the KINDS of boost a full-blown turbo race engine can pump, an all-motor engine with, say, double the amount of static displacement would have to turn some serious revs (with sick amounts of porting and very very aggressive cams) to make equivalent power... that kind of high-rpm tuning would leave you with less bottom-end punch, similar to a turbo-lag effect: there really is no perfect solution.
because of this, and because i know some about all-motor engineering (not lots, but some) i wanna take a closer look at turbos, as that's a very popular way to get a lot of power from a rotary... among other things, they're just cool :D

wakeech

yeah, did that... again, i want something a lot more substantial

thanks though, Dave

babylou

wakeech,

Knowing you want to learn about forced induction and have a techno mindset look for a book written by Corky Bell, http://www.bellengineering.net/maximumboost.html and read away. Corky Bell is probably the best turbo & blower kit designer around. He works with www.flyinmiata.com on all of the well renowned Miata turbo systems. I bet they team up to do an RX-8 system.

wakeech

cha ching!!!! Lou, you da man :D :D

[edit] now only if i could get the ISDN number... ahahaha... i'm just gonna take off to the bookstore now (for lunch)... see what i can dig up

wakeech

sha-weeeeet... got Maximum Boost on order... thanks Lou... anyone else??

Supercharger

Turbo is OK for race cars. Normally aspirated and supercharged engines are better for road cars.

zoom44

there ya go wakeech! enlightenment at last

wakeech

...automotive nirvana is nearly at hand... ahahaha

and yeah, i'm with you for sure on that SC... unless you're a total performance freak, there's not much reason to have a really blown turbo motor... and yes, in this context, using a turbo on an "inferior" passenger car design so the HP numbers can compete with newer model engines would be "cheating"... but in the context of super-high-strung-and-tuned-to-the-max purpose built engines, i really don't know if there would be one supreme aproach: different setups would certainly work better in different applications.

Supercharger

Why turbo is not the way to go (Part 2)

When Gordon Murray designed the McLaren F1 supercar, he insisted on using a normally aspirated engine. A NA engine provides instant and linear throttle response.

When Formula 1 cars switched from turbo to NA engines, they set faster lap times.

The only application where turbo makes sense is drag racing.

wakeech

alright, those seem like a few good reasons, but when Porsche makes a fast car, they insist on using turbochargers...

and about the F1 thing: every year they set faster lap times, and every year they gain more downforce, the tyres get better, chassis more slippery, and power increases... not to mention, a really high power turbo motor would obviously be much better for a circuit like Monza, and a (much larger displacement) all-motor engine would be better suited to the street race in Monaco... like i said, there is no absolute best, it's just a matter of trade-offs and situations, not to mention the talent of the engineers in getting a system to work well, and be well-rounded...

Vaillant

Yeah, that new Neon SRT-4 sure is slow....

From an efficiency standpoint, the turbo is going to be superior. In terms of lag, that's more of an issue of the specific turbo design, though with the direct drive advantage a supercharger will be better.

Admittedly, some turbos are better (less laggy) than others, but with the proper boost control and a correctly sized turbo, it becomes a non-issue.

Hey Wakeech...have you reached the part in maximum boost talking about variable vanes in the turbine? That's the way to go. Too bad there's not much out there currently available.

wakeech

heh heh, i'm still waiting for the copy to come in... a few days away yet.

vipeRX7

In my opinion, I'd rather get an n/a car than a turbo car producing the same horsepower -- you can always add a turbo to the n/a engine. Which is why, for straight line performance (NOT handling), I'd take viper over an F40 - the Viper already gets mucho power without f/i, so you could increase the power for much less. Sort of like the RX-8 and the STi/EVO ... one engine has so much more potential ... :D

DTECH-RX

Those Corky Bell books look like some really good resources! I'll probably be picking those up myself.

Gord96BRG

Nope, that's nonsense and fiction. The only reason F1 switched from turbos was because the rules banned turbo engines. For a year or two they ran NA and turbo at the same time (1989) - the turbos blew the NA cars away.

Aerodynamics had a much bigger impact on lap times - but HP is mostly HP, and there's no way that the 700 HP from the NA engines circa 1989 provided a faster car than the 900 - 1200 HP from the turbos. There's a reason that Keke Rosberg's record lap speed at Silverstone in 1985 (in a Honda turbo powered Williams) was only finally beaten by Montoya at Monza last year!

Wakeech, just saw this thread - otherwise, I'd have pointed you straight to Maximum Boost also!

Regards,
Gordon

rpm_pwr

So this is fiction you're writing then? Interesting. BTW, f1 engines struggle to make half the power of the turbo era. Nobody has ever and probably will ever get near the 1 MEGAWATT motors turned out my BMW et al. Look at Group B rally racing - You could build whatever you like - so what did the top teams show up with? Turbos.

Incidenty Mazda built an NA 21A rally car for group B but it never got off the ground.

-pete

Supercharger

Why turbo is not the way to go (Part 3)

The fastest Saleen road car - S7 - has a NA V-8.

The fastest Porsche road car - Carrera GT - has a NA V-10.

The fastest Ferrari road car - Enzo - has a NA V-12.

Read Corky Bell's book on supercharging.

http://www.askcb.com