OK... maybe I'm a little late but... Check out page the November 2002 Super Chevy Mag. Turn to page 116 and you'll see ATI's ad on the bottom left. See the Nova? Does that ad say 1350 HP on 91 octane gas? Ummm... ONLY 427 CID? LORD HAVE MERCY! :hail: Now I'm curious to know if thats a SBC or a BBC... Hmmm. I guess the turbo boys arent the only ones to make over 1000 HP on pump gas huh? I was starting to lose faith the the blower bandits. What else can ATI pull off?

I should have some dyno numbers by the end of the month

Looking forward to that

Mostly likely big block.....

i know someone with a 502BBC and a D-3 blower that propels a 4400lb impala to 9.20s

Blowers make just as much power as turbos do, there is just more maintenance imo

ROC,

What sort of power level is that 502 at? Also, do you know how much boost he is running?

hp is in the 4 digit range somewhere.......no idea on boost

it is probably like 3 psi on such a LARGE engine like that.....

to anybody trying to decide between turbo and supercharger just think of this

turbo, pros

take less power to turn
can use less restrictive exhaust (turbo's make great mufflers)

cons

Fire risk, these things get MEGA hot

with the turbo spinning in excess of 120,000 rpm the bearings can wear quickly, oil seals can blow meaning a $2000 rebuild (almost every turbo car I know of has had at least one)

car has to idle between 30 and 60 seconds before shutting engine down

supercharger pros

no lag
same boost
far longer life (normaly not more that 8000 rpm)
no fire risk
lower under hood temp
can shut engine off after about 5 secs of idle
that sound!

cons
umm, I dont have one on my sport coupe?
you'll sound like a rice boy if you turbo a 4 or 6 and use a dump valve! (no offence to anyone with turbo 4 or 6 pot cars) (or for that any nissan 300zx owners)

You are forgetting about the BELTS on a blower.......

Also.......i RARELY hear of any turbo related fires

Also, not EVERY turbo spins 120,000rpm only the small ones do. As you get bigger in size the rpms come down and are closer to the rpms of a blower

Lastly....i hear about more blower compressor wheels coming apart and taking out motors that i do turbos

To argue that a supercharger has a longer life, better durability or reliability than a turbocharger is silly. Turbochargers have proven themselves to be the sole choice for a reliable power adder the world over, in countless applications ranging form OTR diesel trucks, aircraft, boats/ships, power gernerators, etc. All of which place a premium on reliability and long life. It is not uncommon for a turbocharger to go hundreds of thousands of miles between rebuilds, while it's common for supercharger to need rebuilding every 35K miles or more. Additionally, rebuilding a turbo does not cost $2000, you can buy a rebuild kit for $100-$200, and the bearings used in turbo's are designed for the 100K rpms of the turbo shaft.

I've enver heard of anyone having an engine fire as a result of a "mega" hot turbine housing either. If they did, then it was obviously a poorly designed system that placed the turbine housing too close to something that couldn't handle the heat. This is no different than not placing headers or exhaust pipes too close to something that would be damaged by the heat. Also, while the turbine housign does get hot, as much as 1300-1400F under periods of high engine load and boost, this is onyl for brief periods of time. Plus, there are plenty of options to manage the heat. I use a turbine housing heat shield from Thermo-Tec that maintains the heat so well, you can literally touch the outside of the ehat shield with the engine running without burning your skin. I wouldn't recommend it, I've just accidently found that out, if you know what I mean.

As for as idling the engine for a few seconds before shutting it down, I've been doing that with all of my hi-performance engines for years after pushing them hard. If you were just out cruising, not pushing it hard, it's not even an issue. But if you just came in from tearing it up, I can't see where 30 seconds is much of an inconvenience.

The whole lag thing is a joke as well. On a properly designed, and sized turbo system on a V8 engine, there is plenty of exhaust energy to spool up the turbo(s). Lag is an issue witht he import cars cause they are generally only around 2 liter or so engines, which need to be spun up to generate enough exhaust energy to spool the turbo. Not the case with a street-sized turbo(s) on a V8. I didn't see any mention of the fact that turbo's provide superior low and mid-range torque to a supecharger since they produce boost at much lower rpm than an SC, which generally doesn't produce maximum boost until 90% or so of engine redline. A turbo can produce near significant boost throughout about 3/4's of the engine's rpm range, therfore having more area under the curve(torque).

I was going to post something similar but it seems like it carries more weight comming from someone with a 1200hp TT car.



The one thing I would disagree with is that you can get the low/midrange response with a supercharger, but you have to go with a more efficient positive displacement like an eaton or a screw type like a whipple... and the eatons have proven themselves for multi hundred thousand mile use.

WRT wear in turbos, there is very little contact between hard parts inside them so unless something goes wrong there isn't any real wear inside. The bearings are semi or full floating and should never touch durring operation, they are designed this way to dampen shaft harmonics. There are only really 3 ways that turbos wear out:
- you have an oiling problem that takes out the turbo
- you send something through the compressor or turbine breaking the blades
- you have a blowby problem or a badly plumbed drain and you mess up the oil seals by forcing the oil past them

none of them are wear issues, but basically operator or a design error.

that's why intercoolers are a great thing to have...

I work for a corprate motorsport facility where we run a fleet of turbo single seater race cars (10) so i have seen lots of turbo cars

they run garret turbo's, without doubt the best

I have NEVER seen a turbo car run for 100 000 without a turbo rebuild

in 1 year of working for this company these 10 cars have gone through about 12 turbo's with a COMBINED milage of 200 000 ( this equates to 1 turbo every 10 000 ish) all of these failures were the same, oil seals.

a turbo cannot be re built at home, with even a large turbo spinning at 40 - 50 000 rpm a 1gramme inballance will destroy the turbo first time it spools up

a co worker runs a VW corrado G60 (supercharged 4 cyl) that has 150 000 without any problems on the origional blower, i ran a Renault turbo with 100 000 on the clock and recipts for 3 turbos

maybee american turbo engines are different, but for european cars turbos are far less reliable than superchargers. as for the fire risk european engine bays are far more restricted than American ones, i have personally heard of 3 renault and 1 Mitsubishi turbo related fire (normaly oil leaks that catch)

i would like to hear views on this as i have always shied away from turbos for this reason, but would love a third gen turbo TA or chev Syclone!

in all fairness this could be a cross the pond thing though, because the only turbo V8 i have ever seen was an '80 T/A 4.9, so un reliable that the owner swapped in a 400 then a 455, but i know these were bad to begin with. all of the other turbo cars i have seen or owned (only 1 for me) were european (ugh)

just for the record, the wear thing normaly goes like this,

spam head thrashes turbo car then shuts off engine without idling for at least 30 secs

oil in oilways of red hot turbo bakes on to oilway walls restricting oil flow

turbo nips due to insuficient oil flow.

typical tubo tirbine housing temp in a garret T3 (european) turbo is about 1000 deg C.

Well, what you're describing sounds mostly like the result of driver abuse, not a turbo desing problem. Most likely, what is happening is that the oil is coking behind the oil seals where it would normally be slung off and plugging it's ablility from draining out of the CRA correctly.

BTW, assuming that the wheels are fine, if you index the compressor wheel before you disassemble it, anyone with a vise and a little patience can rebuild it as long as they assemble it the same way as it was before it was taken appart.

possible, most turbo cars are bought by people who love to abuse them

having just driven a twin turbo V8 it seems they work better on larger engines, this had no lag at all, and you wasn't really aware of the turbo's spooling up

With the inteligence of the normal Escort RS turbo owner in the UK, I wouldn't trust them to make a cup of coffee, let alone rebuild a turbo!

are there any turbo kits available for the thirdgen? i've seen supercharger kits (paxton I think) and will buy one as soon as i win the lottery!

what about all the diesel trucks running turbo's.. they log on alot of miles, usully with 2 or 3 rebuilds in the truck's lifetime (our work truck (94 ford 7.3L turbo diesel has 230,000 miles and one turbo rebuild). somebody who i know who owns a fleet of trucks (transport service) have hiway tractors with well over 300,000 miles on them and no problems.. others with 120,000 miles and have gone through a couple of turbos..
i know of people who have gone thought a couple of eaton superchargers on their thunderbird super coupes' and gtp (Although the gtp from just plain abuse and lack of care)
which one's better?
depends on owner and application in my opinion.
i find that turbochargers need closer attention then superchargers but work better for every day/weekend racing type deals..
superchargers only give full boost at redline..

Diesel burns much colder than petrol, so as a result the gasses driving the turbo are not as hot and the turbo is much cooler, thus preventing the blocked oilways that can occur in petrol turbo's due to heat baking the oil. (the only real weak point in a turbo)

Jaguar XJR's run superchargers, but failures are un heard of. these, like Corrado G60's produce boost from idle to redline (both are screw type blowers, not the roots type)

I think you're right, suitability depends on the aplication and the owner.

What about Porsches and Audis? They use KKK Turbochargers which last forever. If you get sufficient insulation and cooling for the turbo, heat risk is not an issue. As for shaft wear, they have ball bearing shafts which will hardly wear at all, especially if the application is in a mid-sized twin turbo setup for a V8. Superchargers are nice, but they are higher maintnence than a turbo is. The only disadvantage to a turbo is they take more work to install than a supercharger.

Lots of porsche and audi KKK turbos get junked and replaced with the more commont T3's and T4's (I don't know the exact reason). I don't know of any 'ball bearing' turbos that use the ball bearings to support the shaft. The ball bearings are used for the thrust surfaces and every modern turbo that I've heard of has full or semi floating bearings (kinda like crank bearings but they are one piece and should never touch the shaft or the housing during operation and should never wear either). Possibly some of the aftermarket Turbonetics turbos have ball bearings but I can't imagine an advantage.

the ball bearings come in some turbos. i often hear the skyline has these. along with ceramic blades and whatnot.

the advantage to running ball bearing turbos is to lessen turbo lag. at least this is what i was told

my .02

later

andrew

Some of the Buick guys run BB turbos. IIRC Geno was running a BB turbo and it allowed him to run a slightly larger turbo without the extra lag. He runs high nines in a street driven car, so it must work pretty good.

Check out the turbos that Chrysler used on its 2.2 and 2.5 liter motors back in the late 80s and early 90s. Very, very common for them to go 100,000 miles plus without a rebuild. We just sold our car and it had 160,000 + and still had the original turbo.

One thing that increased the reliability was Chrysler's use of a water jacket. I am told that the jacket absorbed the heat on shutdown and locally boiled the fluid thereby avoiding coking.

My SVO has 115k miles on the engine and garret T3 turbo and I've had no problems at all. If you take care of it properly, it will last a lot longer ...

The only problem with turbos is no one makes a nice little kit for my camaro. You guys make it sound easy or maybe you dont.
But anywho the super chargers come in a kit thats made for my application but I have yet to see a turbo kit.
But then again how easy is the super charger kit to install anyways.

the Chrysler unit is a low pressure unit, like saab and volvo. these units are famed for reliability and usually last the life of the engine.

however, high pressure units like the Renault 5 / 11 GT turbo and sierra cosworth will die before 50 000 sometimes half that.

There is a Renault 5 in the UK running 30 psi of boost


hell, 320 bhp and low 13 sec passes aint bad for a front drive 1.4! (yup, 81 ci)

stock is 125 bhp and 16 secs

That somewhat begs the question - How long do you expect anything to live on a 320hp, 1.4L, 30psi boost drive train (which appears to be in a fairly heavy chassis for somethign that small if it's running 13's)?

Makes me wonder what compression ratio, fuel and detonation control is used...

I don't think that anyone would really expect anything on a 1300hp 350 to last 50k miles...

I guess I am not getting it. I don't see turbos as being that problematic.

The "low pressure unit" on the Chrysler is comparable to the stock
boost level on the G-Lader (G60) supercharger. The G-Lader had a bad reputation for needing rebuilds well under 100,000 miles (your friend's experience notwithstanding).

Yes, I am familiar with tweaked turbos and even Renaults. I had a grey-market, mid-engined R5 Turbo II with the 1.4L motor. It didn't use the water cooling jacket as used on Chryslers. Little things can make a big difference in reliability.

No, the 5 GT turbo is a VERY light car, and that is the problem, massive wheelspin everytime the turbo boosts

I simply used that car as an example of how hard people like to push turbo's. It was a demo car for a company called GT tuning, it was simply to show what was possible

the water cooling jacket may be the way to go, as it is normaly heat that kills turbo's every time (i have only ever read about one turbine failure in a classic car mag, i have never seen one,all failures I have seen myself are always heat related)

as for anti detonation, the car was, i believe, running water injection. cheap and very effective

maybe supercharger failures are consistant with different driving conditions, G40 and G60 owners tend to like the twisty roads, where the supercharger is not at a constant speed, this is where turbo's build up a lot of heat, (full boost no boost full boost etc,) rather than a constant mild boost

the supercharger in the Jaguar XJR is good for 300 000 miles. a buyers guide for these cars interviewed a specialist who clames to have never seen a supercharger failure and never sold one.

almost no friction.

Back to what I originally said... Ok if the ball bearings are used on the thrust face, but I don't see the point as a replacement for the semi or full floating bearings used to support the shaft (which sould never actually make contact where ball bearings would). I would be very surprized to find a 'ball bearing' turbo that is actually full ball bearing...