I guess in the drag racing world, you go from gas, to alcohol, to nitro
methane. But since the top-fuel guys are at the top of the food
chain, they use whatever it take to be the fastest. I don't think that
because they use nitromethane they are getting an unfair advantage
over somebody's turbo engine. A turbo engine can be configured
to run alcohol too, so until somebody builds a nitro-methane
turbo dragster and beats the current leaders, I guess we won't
quite know if it is possible to beat the supercharged crowd, right?
that would be cool to see, maybe Apex'i or Blitz will build and import
one one day.

I guess I have a Mercedes bias since my dad has two of them, an '85
500SEL and a '99 SL500. Maybe their production cars, have different
goals such as quiet running, longevity and overall smoothness, over
BMW's obvious focus on performance. But if their smart enough
to go to McLaren for support then so be it. every manufacturer has
some sort of skunkworks for their high performance side. SVT,
AMG, M power, TRW, TRD, Ralliart, etc... Because the production
cars, and the motorsports cars have so little in common, they'd
have to have different minds at work behind them. Besides the block
I'm sure they have very little in common with their production brethren.

Right, turbos and small high revving four bangers go together like
peanut butter and jelly. I totally agree. But doesn't it seem weird
that V8 people, who already have low end grunt, seem to prefer
superchargers for their lack of lag and off idle boost, even though
they already have loads of it and import people like the top end
boost of turbos, for their (our) engines that usually already have a good
top end? Anyway, I guess it has a lot to do with the weight of the cars
too. But that still seems odd to me. Although, a turbo does give
a small car the ability to keep up (or pass) a bigger V8 by giving
the small engine the breathing ability of the cube heavy domestics.

Ditto.

 

Good points... I have a bimmer bias because of my dad, a 2001 740i Sport at present and soon to be a 2003 M5 or 911 Carrera 4 (the toy) and 745i Sport. My mom goes the merc way though. I agree that BMW and Merc cater to different drivers.

Skunkworks is one thing... but the BMW motor is a better performance machine over the Merc block.

A nitromethane turbo dragger... hmmm, that would be pretty cool. Maybe I can convince some friends of mine to try to make the engine with me.

About V8s and superchargers... I really don't know why most V8 owners go the supercharger route. Turbos are more effective on V6s than superchargers. Perhaps it's because V8s are lower revving engines and really can't spool up a turbo and have plenty of torque to spool a supercharger.

What do you think?

Gary

 

part of the reason V8 guys (like myself) prefer blowers over turbos is that #1 there are hardly any companies that make turbo kits for domestic V8s. and #2 the amount of power "robbed" by driving a blower is miniscule when talking about how much torque a V8 makes at low RPMs. A small displacement engine, especially 4 cylinders lack that initial grunt to get the blower spinning fast enough to make it competitive with a turbo's small amount of hp draw. In either case you have to consider how much power the engine produces prior to the boost kicking in.

There is no definative "better than the other", it all depends on the engine and the application

...I love talking about getting Blown

 

Hehehe... Blown.

 

just remembered a cool setup that uses the best of both worlds. I'm sure all of you out there have heard of this car before,(if not, you can't call yourself a rally fan), the 1986 Lancia Delta S4. This beast of a rally car, used both a turbo and a supercharger. The super for low end, and the turbo for high end. was rated at something like 550 hp.

just thought i'd add that little tid-bit.


ps: still like talkin' about bein blown

 

Can you explain this theory to me? What is it about aftermarket cams? The cut? Everytime I have seen a car with a huge turbo go with a more agressive cam, it has picked up MPH. Less aggressive cams hurt a car with a big turbo more than an upgrade. Think about all the forced air that cant get INTO the combustion chamber. And where is the sir leaking out to? I've never heard of this before. Enlighten me

There was one year that the Toyota MR2 used both a turbo and supercharger. Only one year though...kinda makes you think...

 

Why would the companies pass over such a great opportunity
by not producing turbo kits? When I used to read GM High tech performance, I got tired of seeing the same Vortech/383 stroker/nitrous
combination on every f-body, and at the time, one turbo kit had
fianally been developed for LT-1's, by a company I can't think
of now, and that a LS-1 kit was on the way. But as far as revs
are concerned, there's a '97 Cobra and a '00 T/A outside my window
with 6800 and 6000 RPM redlines respectively, so I'm sure they
rev high enough to spin a turbo. My Eclipse tachs out at 7000 and my
turbo starts to spool at about 2500. The exhaust energy from a 302 or
350 should be a lot more then my 123ci at that same speed. Somehow
Jackson racing has been succesful at making blowers work with small
engines. Maybe its just tradition. since blowers caught on with hot
rodders first in this country they've remained strong.

 

[QUOTE]Originally posted by unhdsm
[B]
Can you explain this theory to me? What is it about aftermarket cams? The cut? Everytime I have seen a car with a huge turbo go with a more agressive cam, it has picked up MPH. Less aggressive cams hurt a car with a big turbo more than an upgrade. Think about all the forced air that cant get INTO the combustion chamber. And where is the sir leaking out to? I've never heard of this before. Enlighten me


The degree of valve overlap the cam produces is what allows the air to leak out. Valve overlap is the amount, in degrees of camshaft rotation that the exhaust valve is still open when the intake valve begins to open. All engines have this to some degree. Higher horsepower engines, ie. more radical cam profiles, will have more of this.

As for all that air that is being forced into something? There is always at least 1 cylinder on it's intake cycle letting air in. Otherwise the engine wouldn't run (except for 1 and 2 cylinder engines, but this is a car message board, mo-peds and lawn mowers are elseware.)

 

Did Toyota actually build that car? Or was that a kit that HKS made
for the 1g factory supercharged car? If it was OEM, what year was it?

Such a car participated in SCC's top ten street car shootout, and
Meguiar's sponsored an Integra with a newer version of the HKS
twin charger kit. Very expensive and very complicated, the
supercharger actually disengages when certain speeds are reached,
engine speed I guess, and then the turbo takes over.

I remember reading somewhere how the Lancia car was such
a beast that it was legislated out of existence by the sanctioning
body, and that a few top drivers were killed by it. Pretty scary.

 

About aggressive cam designs...

It's somewhat of a double edged sword with forced induction via turbo. The more aggressive the cam the longer the valve stays open, both intake and exhaust, during the engine TDC and BDC cycle. So, during a cycle there is greater overlap between aggressive exhaust and intake cam opening because of the larger degrees of rotation of both cams. And with that overlap, your boost just goes right out your exhaust.

Now, don't get me wrong. When I was referring to an agressive cam I was thinking more of Jun3s... great for NA but with a really short seat time and long rotation cycle... which boost loss is a problem. I wasn't referring to all aftermarket cams, in fact ITR cams are great low cost upgrade for teg owners NA or boosted. And crower cams are the bomb. If you look at crower and skunk2s, etc., their respective catalogues have different cam profiles levels for different applications.

So, you want an intake cam that lets in as much air/boost as possible during a cycle, and an exhaust cam that lets as much exhaust out as possilbe, but you want to limit that overlap, especially in forced-induction aps. So you want great lift, good seat time, and limited intake/exhaust overlap during a cycle.

Although, some may like to be blown and blow it at the same time... with their cars that is .

 

That's good info. It also explains much better why cars idle so lousy with extreme cams. I just thought the air escaped back out the same intake valve. So going with a less aggressive exhaust cam may be benifical with a big turbo...for more than just a smoother idle, right? A cam upgrade is probably not too far off on the talon.

 

[QUOTE]Originally posted by GPTourer
[B]



Why would the companies pass over such a great opportunity
by not producing turbo kits?

Take a look inside the engine compartment of those cars sitting outside your house. where is there room to fit a set of turbo headers? I think that's the major dillema facing aftermarket parts manufacturers. Centrifugal supers are easier to plumb, cost less, and produce similar hp outputs. It's a no-brainer as far as practicality is concerned. But it would be sweet to see/hear a turbo'd LS1 at full song...

 

It actually was the leading cause of the demise of the B-group cars. The most up-and-coming driver, (still holds record for youngest driver to win a rally stage), was killed while driving his lancia. The reason they (group B cars) were abolished was because the cars were too powerful for the suspension technologies of there time.

 

just talked to an mr2 buddy of mine. Youre right. I always thought toyota made that car. But HKS made a kit for the SC 1G MR2.

 

That car must be a bullet... Anyone know the 0-60 and quarter mile times?

It would seem you'ld want the car set up so the turbo initially helps spool up the supercharger and when the rpms get bonkers go full turbo... Did the turbo feed into the supercharger? Anyone have a pic of the engine?