Supercharger Vs. Turbo- Off the Line Results

[mycarhasposessedme]

Simple logic suggests turbo's run off the exhaust flow..In order to get enough exhaust flow the engine must turn and turn fast..Hense turbo lag... Root superchargers run off the crank of the motor itself.. So when the motor turns so does the supercharger creating no lag and instant boost... So which setup would deliver more lowend torque and power? I believe it would be the supercharger..

Please correct me if I am a wrong...

Thanks very much for that dribbles, that'l do fine.
Its all so simple.

 

[Boosted2.0]

I have already corrected you and told you you were wrong numerous times. ANYONE that knows how to drive would not be foolish enough to launch at idle speeds in a turbo car. My altrac is a 2.0 liter with a manual trans. I launch under 10 PSI of boost atr 5500 RPM. Thats 10 PSI before I ever leave the line or move an inch. If I want to drop the clutch at 8500 I can do it at 13 PSI. A 2 step rev limiter is a beautiful thing. My buddies supra launches at anywhere from 12 to 15 PSI. My point is simply that, as you have made readily apparent, you do not understand a thing about turbochargers or their application in a drag racing situation.

 

[lowfat_hg]

"In order to get enough exhaust flow the engine must turn and turn fast..Hense turbo lag... Root superchargers run off the crank of the motor itself.. So when the motor turns so does the supercharger creating no lag and instant boost"

Not always so.

Even the best setup turbo system will rarely create boost at high rpm with no load.
you need load to create boost, since boost is pressure created by forcing air into the engine, if there is no load to 'push', no boost will be created.
likewise for the roots type charger.
no load no boost.
my car roots boosted engine will redline way before any boost is seen at no load.

as for the comment about no lag with a roots type blower...
there is always lag.
i changed from a no intercooler, small diameter pipe inlet tract from my blower to my inlet to an intercooler with large diameter pipes with a larger volume to pressurise.
the difference in lag, or throttle response was marked.
the amount of volume that needed to be pressurised before the inlet saw boost was increased and therefore lag increased.

just another factor to consider.

 

[stevechumo]

Well, I had been turbocharging the 4 bangers (Honda engines) for a long time and I can share my experience. Laggy turbo isn't the case all the time. If I put a turbo that has the maximum hp capacity (I just make it a simple term) of about 80% more than the stock engine hp, then I can start having the boost at 1500 rpm building up really quick all the way to red line. This means it almost has no lag at all. As you know from 750-800 rpm (Honda factory set) to 1500 rpm only takes a split second.

Within this turbo capacity, I made 65% more hp than the stock engine, and only used about 90% of its hp capacity. Don't confuse this with the average 70% efficiency. This means 90% of the 70% efficiency. This seems to be maxxed out and it's the example of my last Honda Accord.

So many of us have heard the term "turbo lag" is because they come from the cars that have too big turbos put on them. Let's take our 1UZFE for instance. Its stock bhp is 250 hp. If we put the a T70 or a GT40 on it, it might have a real lag. These turbos can almost triple the hp on the 1UZFE. However, if we put a smaller 60-1 on it, the lag will be surely reduced but it still has some lags.

Therefore, I'm currently putting the T04E (its max capacity is 450-475 hp), the largest T04 in its class from what I checked for the specs, I'm very positive I'll almost have no lag for my SC400. The engine is already running, but I haven't run the car on the street. However, when I revved it up to 2000 rpm and released it really quick, the BOV instanly released a lot of air from the intake manifold. This also strengthens my belief it won't have lag once it's really running on the street. Well, let's see about it in a few weeks.

As for the belief of the root supercharger, it runs by the belt but it'll still need to wait to build up air as long as the cranks turns faster. For turbo, the exhaust gas is always in the pipe and it always turns the turbo all the time. This can be similar to the supercharger. However, it'll take some distance for the exhaust to be blowed really fast to the turbine. But this will take a split second. The only real lag is due to the compressor fin to start turning faster to create pressure and blow the air to the engine. Other lag causes can be from the long exhaust pipes and intake pipes, but if done right, it won't be the problem.

 

[SC400TT]

Jibby, you have got to be one of the funniest guys I have ver met in Cyber Space...:nana: :bigok: I can't help but love ya...When we do the Texas shootout next year, I hope you can make it. I truly would love to see your car, and run you as well...Who knows, it might turn out like this...:nutkick: It is all in good fun. Just know that If I flame you, it is in fun. I do not doubt your car is quick, but consider your weight...Significantly heavier car...You have to add significantly more power and torque to the wheels to get the same launch as Justen. And as I said, Twin Turbos done right will absolutely scream off the line...

I would love to see Justen's car in person, and get a ride...That would be exhiliarating. I would also like to ride in your car too. SO, relax up a bit, my friend. Some times you post up like a raging bull that never stopped to think about what walls he was attempting to break through...Remember, some walls can be impenetrable...Take what the learned guys have to offer here with humility...They mean you well, and they truly have earned the respect they deserve because they have paid the price of time, and much reading, studying, hands on trial and error, etc. They know their stuff. I believe most all of them really like you...It's just that sometimes you post recklessly...But frequently, you do so in such a way as to really make me laugh...I really do appreciate your contributions, especially your attitude, but remember, some of the guys posting here are way above most of our heads...Give them the respect they so well deserve...We can and do learn a heck of a lot from them...

Ryan

 

[jibbby]

Hey Ryan that's my MO.....Hard to teach an old dog new tricks...That's probably why I've been banned on just about every Lexus forum on the internet...:dunno: I have a tendency to get competitive....

I hear you on the heeps.. I too want to roast Justen's car as it sounds hella fast..:yikes: ...Also, you can roast my car anytime as long as you race me in yours after.....It's all good my friend...:fing02:

Just so you know when it looks like I am flaming someone or firing back most of the time I am mostly just fooling around.....Mycarpossesme is a good example of that...Forum battle savy are the words that come to mind.....

Hey, I never said I was sharpest tool in the shed but I do know my share of automotive knowledge... I lived and breathed these 1uz-fe motors for years... Grew up on the root chargers, big and small block American motors, etc...Did my share of engine swaps, builds, mods and budweiser drinking, etc....Had my share of turbo boosted cars as well.

In conclusion, I am not too proud to say I am wrong at times as it happens..No problem and that is how we all learn and grow.... I can be humbled no problem...I just don't like when people talk smack...I feel compelled to fire back and not be the bigger man...Eye for an eye baby and not turn the cheek....:twak:

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Back on topic -

OK so I am wrong about the difference between root chargers and turbo chargers?... So you guys are telling me there is no difference in lag time between a properly fitted turbo and root charger?....

If that is the case that is news to me... I have always thought the root chargers had the slight advantage over turbo charged motors in the lag department...

Again, a straight answer WHICH WILL HAVE MORE BOOST LAG a properly fitted standard turbo or a mid size root charger that is dialed in?

I am still unclear on this from the responses I am getting?

I also understand the smaller the turbo the less lag it will most likely have...Larger turbo's more lag time...

 

[jibbby]

A better actual comparison - Which application when mounted onto a 4.0 liter sized 1uz-fe motor will yeild the least amount of lag time?

A) A single turbo T04E
B) An Eaton M90 supercharger

This is basically what I am getting at....

 

[Treynon]

a whipple charger


:burnout:

 

[cribbj]

Take the earlier example of three identical cars, slap a turbo or turbos on one, a PD compressor on another, and a centrifugal SC on the third. Everybody sizes their setup so they make the same peak HP. Nobody has a HP advantage, and no other changes are allowed.

No NOS, trans brakes, 2 steps or line locks. Trannies are manual.

Assume there are three genetically identical clones driving the cars ;-)

Everybody rolls up to the line, launches and goes. What we're looking for is how the same identical setup responds to being boosted in three different ways.

Who has the best 60 ft time?

Who has the best 0-60 time?

Who wins the 1/8 mile?

Who wins the 1/4 mile?

(I don't have a favorite horse in this race as I own 2 turbocharged cars, and am building a supercharged motor at the moment. I like blown motors in all varieties)

 

[stevechumo]

A better actual comparison - Which application when mounted onto a 4.0 liter sized 1uz-fe motor will yeild the least amount of lag time?

A) A single turbo T04E
B) An Eaton M90 supercharger

This is basically what I am getting at....

Honestly, I don't know. I never experienced driving the M90. And even if the M90 can make the car jump at the first few feets, I believe the T04E will pull the car after a few feets really quick while building the boost at the same time. The result at 0-60 mph or 1/8 mile? It's hard to say. For daily street driving? There shouldn't be any difference because you don't floor the gas all the time and both M90 and T04E should feel similar.

But in this case at top end power, the T04E will win for sure because it provides more hp than the M90.

 

[jibbby]

Cribbj and I pose the same question.... Even if I am wrong in my assumptions I am beginning to think no one has real experience between all the above boost applications...I don't think we will ever get a real correct answer on this one...Just alot of different opinions..

Turbo guys knows what the turbo's can do, supercharger guys knows what the chargers can do.. All applications considered on an equal car maybe RMS can answer as he probably has the most knowledge and experience out of the whole group here... Off the line power and no manual or human clutch error involved...Just engine boost and power from a dead start...??????????????

I still find it very hard to believe a standard turbo application will experience less lag time then a standard root charger setup... Come on isn't that common knowledge?

I do know for a fact that a nitrous load would yeild the best results for instant excelleration over any boost application...That is why nitrous wears out the engines so fast, no gradual increase just a jolt... Rpms soar with nitrous rather then naturally climbs with boost..

 

[JustenGT8]

Jibbby,, as you know the 2 big differences are the roots is a mechanical drive and the turbo is exhaust drive; the roots is positive displacement and the turbo uses a turbine to speed up the air.

The strength of the roots is as soon as it's turning it's moving a defined amount of air per rev and if it's sized right this will mean boost is there all the time (it's more about flow than boost but boost is good enough surrogate for this discussion).

So off the line with a correctly sized SC you will have good boost for a hard launch.

The turbo being driven by the energy in the exhaust gases needs engine load to generate boost. This is where you have missed the point. There are a number of ways to generate that engine load and therefore get good boost for the turbo cars launch as well.

You can have small turbos
you can load the engine on the clutch
your ECU can run an antilag setup which is just playing with ignition timing and fuelling
or you can setup the antilag with additional air injectors as they did in the early days of WRC

So, in a pure off the line, do the best you can, there's no reason why a turbo will be disadvantaged.

Now where your 'instant' SC boost example does apply is where you are just cruising along and you suddenly want to nail it. The SC will have the boost advantage here but even then the turbo is just a down shift away and not a performance issue in my mind.

 

[rms]

Thanks for the vote of confidence jibbby, but with road applications i'm not sure that race car experience is always relevant.

I think a point being missed in all of this is engine capacity.
If the engine is large enough, it will light up the tyres off boost anyway. There will be no turbo lag as such. There is no substitute for cubic inches.

A 1500/2000cc engine would be different. A std WRX has significant lag even with the small turbo.

With Cribbj's scenario.
Large engine - probably not much difference.
Small engine - a PD S/c 60ft time may be better, 1/8 and 1/4 - it would depend on how much quicker the 60ft time was (if any).

The most obvious difference would be throttle linearity, N/A and PD S/c will be more linear.

Of course I would be more knowledgeable on this subject if GT8 would allow me a few laps at Wakefield Park. :burnout: :spank:

 

[JustenGT8]

I reckon that can be arranged Erol, once the damn clutch is sorted (i sound like a broken record)

I'm considering some rather major allow fab work seeing the engine is coming out so might drop you a line to discuss if you reckon you'll have the time? Car needs to be running for Toyota Nationals at Easter at the very latest.,

 

[stevechumo]

It seems somewhat unfortunate for us to compare because the supercharger guys live in the different areas where the turbocharger guys don't. While David (Lextreme) is having a development on his supercharger set up (The Fish), he and I are talking some local guys to go for this route. And then hopefully we can be fortunate enough to compare between the turbo and the supercharger. On the other hands, some M90 owners (Scott, Carlos, Cobra...etc) on the 1UZFE and the turbo 1UZFE owners (RMS, Chrisman, Ryan, and David) didn't record their launches officially, except you, Justen. :bigok: If they do, then we'll have a better idea of the comparison.

 

[rms]

Steve,
Don't have a turbo UZ, the race engine I built is N/A. Not in either camp really.

The owner of the clubman sports car ( I drove in an enduro race a while back, RB25 Nissan N/A 6 cyl ) and I are having the same discussion re turbo or M90 for the next enduro race.
M90 - response off corners, linear throttle, but will it have enough grunt top end ??
Turbo - enough grunt top end, but will the response be linear off corners ??

At the moment the V8 Supertaxi's are in the road under brakes and cornering but dissappear down the straights. We need to stay close to them in a straight line, but will a turbo compromise our corner speed and exit ???

Decisions, decisions, decisions !!!!!

 

[jibbby]

So it safe to say a properly fitted turbo is more aggressive at full throttle with the RPM climbs then let's say a good fit root Supercharger in most cases???

So is it also safe to say if your on a race track with many turns maybe it would be better served to run a supercharger over a turbo'd motor for that steady increase in power when turning in and out of the bends??????

 

[rms]

Probably right jibbby.
But it is very difficult to be dogmatic about it, there are exceptions to every rule.

 

[XR8tt]

On road with engine at reasonable rpm there wouldn't be much in it!!
There are too many variables and most would be up to driver control..
On the track its not all about straightline speed...On traling throttle through corners the turbo is spinning away, it doesn't stop..
In most cases where rules allow tuirbo/s are used...
Indy cars and World Rally cars...

 

[Blizzy]

The most obvious difference would be throttle linearity, N/A and PD S/c will be more linear.

That is a great term -likely more appropriate than "lag"- to differentiate between turbo and PD s/c set ups.