Car questions. Turbo, AWD, Viper...

Factual Questions
21

Did someone say Turbo-chicken?

I happen to drive an 85 Turbo-chicken (Thunderbird Turbo-Coupe) with 145,000 km on it and the turbo runs as well as ever. In looking at 100’s of owner reports I have rarely seen any owners complain about turbo failure in their Turbo Coupes, SVO Mustangs or Merkurs which all share the same 2.3 litre turbo configuration. Later models added intercoolers which added to the horsepower and reliability of the turbocharger.

Other cars that use turbos are less reliable, your VW turbo diesel will wear out the turbo much sooner due to the constant use the turbo experiences. This goes for turbo-diesels in general.

Ford had a reliable design going for them… it is a well designed configuration in that the turbo only kicks in under moderate to heavy load, the 2.3 in itself puts out around 125 HP which is enough HP for toodling around town. Punch it and it becomes an entirely different driving experience. Add the great suspension and I have a fast and luxurious car that handles like its on rails. I am planning on adding a turbo regulator and an intercooler to my car in the future so that I will have more horsepower at the bottom end.

I rarely exceed 3500 RPM in my car and it cruises at 70mph with the engine turning around 2500 rpm. Mileage is around 35mpg.

Why have North American manufacturers gone away from turbo-charging?

Cost and image.

Replacing the engine in my car would be very expensive and many people that have blown up their Thunder-Chickens (usually through racing) have replaced the 2.3l with a 5.0l V8 which is much cheaper. I have a older friend who is a Mopar fan and he made fun of my four cylinder… that was until I took him for a spin around the block. It was one of the few times I ever pushed my car to it’s limits.

Never make fun of a man’s ride.

22

For those curious about my experience, I’ve:

rebuilt Ford 1.9l, soon to rebuild a Chevy 2.8 daily driver, and Chevy 3.1 turbo/racing engine

swapped in a new 1.9l into an Escort, Geo 1.1l into a Metro, Dodge 3.0l into a Voyager

replaced a transmission on a Ford Escort, and Voyager

replaced an automatic tranny with a manual in a 90 Z24, and a manual with an automatic in an 89 Z24. 3.1 and 2.8 liter engines, respectively. Actually the same engine, but the 3.1 was bored/stroked from the 2.8 for the 90 model year.

I’ve also done basic work, tune ups, etc but not full rebuilds on Chevy 350s, Ford 351 Windsors, Merc flatheads, Chrysler 2.2s and 3.0 (actually the last one is a Mitsu)… uh, well, just about every domestic engine make and size since the 80s. Some foreign work also, mostly on Mitsus and Nissans.

Not exactly an earth shattering list, but hell, I am only 19. :smiley:

–Tim

23

Well, I have a different take on this…

I hang out with an Import Racing group, and these guys are into their cars something fierce…

But you really can’t compare imports and american, it’s really 2 different ways of looking at cars.

See, most of us Americans are inthralled with displacement, and big engines.

The import guys are interested in seeing just how much power can be wrangled out of the little 4-banger engines.

There is a HUGE amount of competition and animosity, which is typified by a lot of the stuff said here: *"…us Americans build real engine that don’t need 'em." “…I don’t want a stupid turbo or supercharger instead of my Big ol American engine. I want to hear and feel that rumble, not whine along at 6000 rpm just so I got a little power.” *

Before the fire starts, however, I’m just using those as examples… the import guys are just as bad, but I do have to admit that I’ve seen races, and when the import guys get beat, they tend to be a little more gracious about it.

When the Civic Si’s pull up and spank a 5.0 Mustang, usually they get dirty looks. Heck, when I tried telling my Uncle-in-law about some 9-second 1/4 mile Hondas, he called me a liar!

Just my 2 cents… me, I’m gonna drop a v-8 in my volvo, and that’s gonna be fun.

also, the Bertone Volvo’s are rare, sort of the supreme luxury car for Volvo, leather interior, wood grain, better engines…

24

I hang out on http://www.dsmtalk.com sometimes, alt.autos.chevy, alt.autos.hot-rod, rec.autos.tech, rec.autos.rod-and-custom, newsgroups like that.

The 9.25 sec Honda is a tube-frame CRX with a nitrous and turbo 2.2 VTEC, right? Can’t remember the guy’s name right now.

Now, you’ve gotta do alot of work to a Civic Si (Si-R to you Canucks) to beat a 5.0, but the DSMs I’ve been talking about can take a Cobra or SS with VERY little modification. Electronic boost controller, fuel pump, exhaust, and larger intercooler piping, mainly.

So yeah, it may be surprising to hear, but a turbo 4 banger is waaay easy to make go WAAAY too fast, and, unlike a 9 sec V8, you can dial the boost down and still have it be a smooth running street machine, too. Usually you can hit 12s or 11s without ever cracking the engine, whereas with a V8 you’ve gotta do ALOT of internal work for that. Not to say I don’t love the rumble of a V8, but they can be harder, no, scratch that, more involving to make fast. (As a disclaimer, any attempt to make more than ~500 hp with a Mitsu 2.0 turbo will result in a bent rod, detonation, and fuel cut)

Side note: Why does a port/polish job drop low-rpm torque? IIRC, torque is just a measure of HP@5250 rpm (not really, but you know what I mean, I can’t think of the equation off hand). So wouldn’t raising HP at ANY point raise torque, also? Or would a p/p just ‘peak’ the power more? Jesus. I can fix an engine, but I know almost nothing about engine theory. Anth, what’s that engine theory book you tout? I guess I should read it.

–Tim

25

Actually, the 5.0 we beat was a convertible, so that would make it an automatic… I guess that one of the guys has beaten a Manual in his Si, and all he’s got going on is Intake-Header-full cat-back exhaust. also, V-tec controller for Apex…

Ah well… sometime next year I want to pick up a Civic Hatchback, and start my other project (13 second 1/4 mile daily driver… I’m gonna try to be all engine to… hehe)

26

Homer,

Have you seen my long posting in this thread?

Torque and horsepower

If you are talking about raising horsepower at any particular rpm, then yes, you are also raising torque as well at that rpm. And the other way around.

Who says porting and polishing must lower low-end torque? The only way I could think of how it might do that is by disturbing the low-end pressure-wave supercharging effect that the intake and exhaust system can have. This effect leads to an old mechanic’s saw “Putting headers on a car can make it less powerful and hurt your low-end torque.” Pressure wave supercharging has a more pronounced effect at lower rpms, but to what extent porting and polishing would hurt that rather than help…that seems like a really hard generalization to justify IMO.

27

“No turbos: American car manufacturers are not alone. Japanese have abandoned turbos as well. Why? Reliability,
requirements for high octane fuel.”

One instance doesn’t prove anything but I have a 1986 300ZX with the original motor and original turbo, 189,000 thousand miles. Still goes like a scalded cat.
It is actually better to use 87 octane gas. You don’t need high octane unless you set the boost very high. If the boost is very high you need an intercooler or the engine can’t handle it. You get detonation. They are very reliable.

28

Anth: Thanks for the torque vs. hp link. I’m gonna read through that. Here’s a cool link for you: Pretty picture Uh… I just saw that now and I wanted to share it.

The reason I ask about the p&p job is because my dad is convinced that a it would make me lose low end torque for high end hp, but I’m convinced that it would open up the engine along the whole rpm range, because the engine will breathe better regardless of it’s rpm, and a better breathing engine is more powerful. He also says an open exhaust will ‘burn my valves’ and I’ll lose torque (that would be affected by exhaust scavenging, right? lowers the volumetric efficiency?) but he’s not entirely specific as to what a burned valve is or why an open exhaust would cause that.

Chronolicht: You also should have a EG temp gauge (ahead of the o2 sensor, probly about 6-8" from the head, should check at ~1500, IIRC) at high boost to see if you’re leaning out too much, that also causes detonation. Check for small aluminum specks on your plugs. An intercooler lowers in the incoming air temperature, which in turn makes for denser air (that’s why an intercooler lowers boost pressure, too, right? bueller?). The denser air will cause a leaner situation if your fuel pump can’t supply enough fuel, your injectors are too small, or the MAP or MAF is set wrong. How much boost are you running now? (Just curious. I like turbos.) You could also run a A/F sensor to your oxygen sensor. Anything about .73 volts is good (.71 to .75) IIRC. I haven’t been keeping up on turbocharging lately (busy) so I’m getting hazy on the particulars.

Geez. I’ve probably made so many errors in specifics here it’s not even funny. Bedtime, I guess. After I read that torque vs. hp thread. :smiley:

–Tim

29

I’m absolutely horrid at math. Okay, so torque is p=tr/5250

So how can you have higher torque than hp if 1) torque is a derivitive of hp and 2) hp and torque are equal at 5250?

Like my Z24 has 140 hp and 180 lb/ft… yet some cars will have 180 hp and 140 lb/ft…

I have so much to learn!

Thanks for that link. I’m going to have to get that textbook, maybe. I like working on cars, but to be an effective little bee, I really need to know WHY something works, and how to make it work better.

That, and I’ll likely need to have a custom grind cam for my turbo 3.1

–Tim

30

There is a lot of back ‘n’ forth about the generalizations folks are making on cars.

If someone says, “There is no replacement for displacement” it is pretty well accepted that statement is true. We don’t have to hear about some twin friggin’ turbo 3.0 V-6 that cranks out 260 HP. Zippity friggin do-da, it has a nice horsepower peak.

To defend my Mustang Vs. F-Body post, “Arghh! Give me a break!” The point was: Real world (where we live), and it’s Mustang Vs F-Body at a light, you’d be a damn fool to bet on the F-body, which is probably stock and, to make matters worse, probably an automatic, and probably has a 150 pound bass system in the trunk.

Recall aside, the twin cam 4.6 Ford motor is nicer than the f-body 5.7. BUT, even a modern v-8 such as Fords STILL struggles to keep up with an iron horse push rod v-8, I’ll give you that point: DISPLACEMENT FOLKS!!! 1.1 litre apart and Ford can’t beat an old 5.7!!! Viper: Big and old engine! A pushrod engine in a Super Car!!! I’m sure these pushrod owners are afraid of twin cam v-6s!!! :slight_smile: DISPLACEMENT AND TORQUE AND BIG POWERBANDs are the way to go!!!

After local trips to the official sanctioned drag strip and the not-so-official drag strips, I can draw some conclusions:

A hot-rodded Civic could beat a few stock Stangs and F-bodies, but in general, they ain’t scarin’ any real hot- rodder with a tweaked V-8.

Mustangs and F-bodies go back and forth, and it’s the Mustangs that get more engine-work to win, but f-bodies can’t claim a decisive victory. (The most effective Mustang tweak not found on many f-bodies: Dropping in a better ratio rear gear. I know f-body guys do it, but not with the frequency of Mustang owners).

You know, I love to see 190-220 HP v-6’s that claim to be as powerful as V-8s, and little hot-rodded 4’s that seem to be fast too, but for the love of god, they just ain’t as earth stompin as a big ol’ v-8.

How long before someone makes a v-6 as powerful as a Viper? I don’t see any v-6’s challenging Cobras, or Vettes. And I don’t see any performance trucks with V-6s.

Torque counts (repeat after me: “Torque counts”), as does a nice flat and usable horsepower band. Engine size accomplishes this. Torque’s importance increases when the terrain isn’t flat, or you have a passenger, or you blow a shift, etc.

V-8s and displacement rule. Don’t be a friggin’ Euro-head and get jazzed up because your Euro-Jap car cranks out 220 HP.

OOH! Look, honey, my Maxima makes 222 HP! Why does it still take me 8 secs to get to 60mph?

Because, sweetie, it’s got a great peak HP number, but we’ve also opted for the automatic, and Nissan isn’t exactly spacing the gears to use all that “torque”.

Yeah, darling, I wonder what the rear-wheel HP numbers look like.

I wonder why the fastest cars come with such big engines when there are all these great 3.0 and 2.2 engines with just 6 and 4 cylinders?

Gee, honey, I think I’ll buy a truck next. I’m sure a 2.2 Civic engine could really haul some ass.
:slight_smile: Thank God that when I add up the cyclinders in both my cars, I get 16. I’ve driven BMW this, Shelby that, Civic whatchamacallit, Volvo turbo etc, Maxima thingy, Audi Shmaudi and I’ve come to one conclusion:

Displacement Rules. :slight_smile:

31

I hope you’re not referring to me with the “sweetie” and “honey” and whatnot, and for your own sake, I TRUELY hope you’re not speaking to Anth. Now before she comes and rips your post to shreds, I have a few things to say.

First off, there’s no need to be condescending and pedantic.

You have a preference. That preference is American pushrod V8. Lots of people share it. But repeat after me: It is a PREFERANCE. Everyone has a different one, and not a single one is the ‘right’ one to have.

Second, there is no comparing a pushrod V8 in a Nascar to a pushrod V8 in a production car. What’s the redline on those things, again? And don’t Indycars use I4s nowadays? Sorry, that’s a pushrod in a Viper, not a Nascar. How does the Viper fare in acceleration vs. a Shelby 1? That’s got a supercharged V6 sourced from an Aurora. How does a Viper fare against a mildly tuned 3000GT VR-4? That’s got a 3.0 V6 TT. How does a Viper fare against a mid-range tuned Eclipse GSX? It’s got a single turbo I4. The answer to all three of these is ‘not very well’. This leads me to my third point.

Third, POWER is POWER, regardless of how it’s made, a corallary to that is that TORQUE is TORQUE, regardless of how it’s made.

A good, flat powerband is VERY nice to have. But it is just as easily made with a correct size turbo, or correct size supercharger pulley system, as it is with CI. Read Anth’s post about HP vs. Torque that she linked to. I did.

Fourth, displacement is displacement. Let’s take a 5.0 (302) n/a engine. Now let’s take a 2.5 (173, right? 189 is 2.8) turbo engine pushing 1 bar (16 psi, or, 2xregular air pressure). The 2.5 liter engine is effectively a 5.0 liter engine. What’s the problem? If I ran my 3.1 liter engine at 20 psi, I’ve effectively put a 6.7 liter engine in a 2200 lb chassis. That is going to be fast.

Leave emotions at the door. This is a place for facts.

Manny or Chronos, I think this belongs in IMHO now?

–Tim

32

Well Homer, this is a very common tale that people toss out when talking about exhaust mods - the apocryphal tale of burning the exhaust valves due to open exhaust.

What some more scientific persons have tried to explain it as it if you were running with a true open exhaust, that it just short (12 inch or so) pipes going from the port and into the air, then there is a possibility that during shutdown, the pressure wave effects will cause fresh air to be drawn back into the cylinder, thus hitting the valves with cold air. And warping the valves.

Who the hell drives with 12 inch port pipes? I’m assuming that every street car with exhaust mods will at least have a header, and a long section of pipe going to the end of the car, and a muffler of some sort. I do not see how enough cold air can be drawn into an engine on shutdown to hurt the valves. You need some serious cooling going on to warp the exhaust valves.

One theory as to the origin of the old saw is that the valves get injured due to the combination of a too-high lift and duration cam, coupled with hard-ass driving. Valves and valve seats are many times left stock by the hot-rod tinkerer, and not upgraded to stronger or better ones.

What he’s talking about with “exhaust scavenging” is the pressure-wave supercharging effect. But one cannot apply one universal exhaust axiom to this. Pressure wave supercharging/exhaust scavenging is affected mainly by the header geometry and length, much more so than anything else on the back end.

Pressure wave effects on the exhaust end need not be magic. Somewhere, I have a book that tells how to calculate the ideal header pipe length and diameter to get your peak scavenging effect at any rpm you choose. I will look for it, as it might be interesting. In general, longer header pipes shift the peak scavenging effect to lower rpms, and short headers pipes shift the scavenging effect to higher rpms. Of course, it is a simplification, but the principal holds true.

Same on the intake manifold. A “high rise” manifold (or “slab of ribs” manifold, like seen on some pickups) uses longer pipes to accent the supercharging effect at lower rpms.

33

Power = (Torque * RPM) / 5250, if power is measured in horsepower, and toque in lb-ft. Likewise,

Torque = (Power * 5250) / RPM

Having a torque higher than horsepower at a certain rpm is no magic. Consider:

Torque: 250 lb-ft at 1500 rpm
thus, power must be (250 * 1500) / 5250 = 71.4 hp at that specific rpm.

Or consider
Power: 300 hp at 5500 rpm
thus, torque must be (300 * 5250) / 5500 = 286 lb-ft at that rpm.

You just have to consider that these are at different engine speeds.

Also, I would not recommend the reference I supplied in the other thread, as it requires Calculus to Differential Equation level math to read.

34

“The Brits think we make crap and you can’t sell a non-Jeep American made car in mainland Europe or Japan.”
The phrase “Yank Tank” springs to mind.
Its only because so many people associate American cars with big oil tanker lookalikes that can’t corner.
Besides the point-“Ford developed a turbo 'Stang, bolting a turbo onto a 320 hp Cobra Twin Cam 4.6 liter V-8, but is going to abandon it in favor of the 5.6 liter”
4.6 litres and 320 hp you need to turbocharge it?
Sort of puts my Mum’s 1200cc Renault Clio to shame.

35

*A hot-rodded Civic could beat a few stock Stangs and F-bodies, but in general, they ain’t scarin’ any real hot- rodder with a tweaked V-8.
*

well of course… displacement generally equals power. This is a given. However, displacement can be countered by the correct aftermarket, and turbo’s are part of that group.

I would like to thank you for confirming my earlier statement, BTW…

At this point, in the club that I hang out with, is an Integra that should be able to pull low 13, high 12 second quarter mile. This one is all engine.

Yes, a V-8 puts out more power, we all know that, but where the battle gets fierce is trying to get folks to acknowledge that the 2.0 liter 4 cylinder can be made it’s equal or better, cheaper.

and if Honda made a v-8, it would have 1000 hp.

36

Tiny turbo’d 4- and 6-bangers may have more top-end horsepower, but find me one that makes 300+ lb-ft @ 1500 rpm like my AMC 360 :smiley: That is some serious low-end torque. Of course, the redline on this thing is around 5000 rpm, max hp 200-ish @ 4000 rpm…it may be slow, but it’ll pull.

Back to the OP re: AWD-- The simplest explanation for the lack of AWD in the US is that it didn’t sell. Eagle (under AMC) was available in AWD, and with the same transfer case as the fulltime 4wd big Jeeps (strong!), but Chrysler eventually dropped the line.

37

Thank you for at least dropping the HP question…

And have no fear, when I need to tow a trailer I would use a Truck, but for just racing, or daily driving I like to see what can be done with the little engines.

And the fella I mentioned has spanked several trucks, Magnum V-10’s, and so far 1 Lightning from the line and down the road.

Me, I take a bus… hehehehhe

38

Well, this thread is largely just people boasting about their cars and arguing about which is best, but I think there’s still enough factual material here to keep it in GQ. No promises on where it’ll be tomorrow, though.

39

Most Diesel pickups are turbo’d. As for the question of why there’s not that many Diesels, us Americans are just more used to gas engines. ::shrug:: And gas is (relatively) cheap over here. I, for one, would love to have a turboDiesel Grand Cherokee. Sadly, they’re only available in Europe (and even then I couldn’t afford one…)