Louis

iTrader: (7)

Thats good power!! Really good power

Turbos are a very complicated beast for sure in the 750-1000 rwhp realm of things. Lots of stuff to keep track of.

topend

turbos are peaky and have a short powerband which why they work well in diesel engines . if your going to compare centrifugal superchargers to turbo chargers i would suggest doing so on a more accurate dyno like a mustang dyno. u cant compare dyno jet results with mustang dyno results. For more area under the curve i would suggest a whipple or roots.

cablebandit

iTrader: (37)

780rwhp thru an 80e..unlocked 9psi at 12.7 deg of timing dynojet.

MY99TAWS6

iTrader: (3)

Umm peaky and short powerbands?? Maybe if a guy puts in a huge turbo way oversized to the engine.
Then I agree.
But if you size the turbo or turbos reasonably you have a great powerband. From say 2000 starting to spool to maybe 3000 full spool and carrry full boost all the way to redline. How is that peaky and short. You can also set how much boost so its not peaky ,modern electronic controllers can do great things with turbos.

No one seriously thinks the centrificals or any super is more efficient than turbos. As long as supers are run off the crank its going to be a fact of life.
Turbos destroy centrificals in area under the curve unless again you are talking a turbo that way way too big. LIke putting a 1000 hp turbo on a 4 cylinder ,yeah its going to be a horrible match. Or a way way too small one.
Turbo systems need to be sized to the engine and driving requirements.

Turbos are not rediculously complicated they are quite simple. The factory has made millions and milllions of turbo cars. Hardly any supercharged cars.
Even the cobalt are now turbo not super I hear.
Miilions of semis are running turbos and many many trucks.

Sized properly you get great power, great powerband. And good reliability.

Roots blowers are good in some applications. They look intimidating and sound neat. They can really look good sticking thru the hood like in Mad Max.
They can make a lot of power. But they can also have way too much bottom end and die on top or like the new twin screws also have too much bottom but not die on top. You can only deal with so much power down low. One advantage to the centrificals. They are easier to control down low for power. The boost ramps up. and turbos also generally start spooling up then the boost hits full on and holds to redline but by having the spool up a bit higher in the powerband you can help the too much too soon too low problem and they can be finely controlled for gear, rpm by electronic controllers .

Inital install can be a bit more intensive on the turbo. My kit took like 100 hours but a lot of that was to wind up with a near factory looking install.
You can't even tell there are two turbos in my car if it wasn't for the litlte aps logo on the intercooler you wouldn't have a clue. You can change the spark plugs. Get to the top of the engine.It keeps the air ,didn't really relocate much either.

So yeah had to put a couple oil drains in the pan. Had to put a couple of fittings on the head and block to send coolant thru the turbos. Hardly super complicated. And yeah you have to tune afr and timing for the turbos but you have to do that for the supers and you have to upgrade the fuel system for any power adder.

I like all the power adders and have been in both turbo and ati cars. And huge roots BBC. And paxton lt1. Sts cars. Nitrous cars.

I have seen an NA heads/cam/header bolt on 346 ls1 destroy repeatedly an ati lt1. The ati got so mad he turned up his boost and took out his motor.
Now not saying the ati was crappy just that peak numbers are one thing and area under the curve is another. And I don't have the dyno graphs to compare that NA car to the ati car and there are lots of variables.

But from driving a d1c ls1 auto and from driving my TT its night and day difference and yes I realize I am a 408. The auto was a 346. Still the turbos start spooling up at around 2000 can hit full around 3000 in third. They will hold full boost to redline . The ati ramps up. Hit them both in third and really see the difference or fourth gear roll ons with no downshifting at higher speeds. Or a fifth gear pull that would really show it. If you can gear down then you can make things closer .Around town in third band down to second on the turbo. It will be at instant full boost. The ati will also have more boost when geared down but not full..it needs to be near max rpm to make max boost. Turbos don't if sized right.

And don't care what dyno you measure on. Turbos have troubles spinning the tires off on the dyno anyway. Turbos win in theory and practice unless
you really mess up on sizing. But supers are still fun and so is nitrous.
And nitrous can have great area under the curve as well. Until the bottle runs empty.

On the track it evens out. You rev that centrifical high up and keep it up there with fast shifting stall converters..etc. Nitrous works great at the track too. On the street its different story in the real world. Roots and twin screws are awesome on trucks for pulling but the turbo diesels are no slouch at pulling either!

Power adders all fun. And even though I said in theory and practice if sized right the turbos are superior I might still buy a procharger for my 96z and a magncharger or kenne bell twin screw for my future vette. Why because I am a speed freak and each power adder has its own unique flavor and pros and cons. Blonde or brunette,redhead..all good!
And if you really want something fast then combine a built big cube NA with twin turbos or super and add some spray. Spray can play nice with supers or turbos. Instant spool up on the turbos and supercools the intake charge.

All good!

cablebandit

iTrader: (37)

A "screw" car just kicked some *** at Orsca in SC. Gotta find what works for you.

topend

your only thinking of the compressor side of the turbo. Sure you`ll have the same boost psi from 3000 rpm to redline ,thank your wastegate for that. So heres the question for u.. what is your exhaust turbine pressure like from 3000 rpms to redline????? likely to increase with rpms right????
now imagine what this back pressure does to your motor and its effect on the powerband.

cablebandit

iTrader: (37)

oh lawd...someone tell Lynch he won with the wrong technology this weekend.

davidadavila

for me i would have to say that the procharger set up for a average street driver like myself that does hardly any racing, just the fact that you can keep all the stuff that you have bought for your car before you went f/I is great, like headers exhaust which can be is much as 1500 or more depending on what you bought, you get to keep your air conditioning installation is way easier than a turbo setup, you can do it in a day..price is also a big differnce too..I know the original question is basically which makes more power, but if you concider how much power your making with way less money, you get a better return with the procharger kit in my opinion.

Louis

iTrader: (7)

How old are you, and what is your background in turbo technology as of late?

MY99TAWS6

iTrader: (3)

Topend your theory is all very nice. But in the real world turbos are the king of the poweradders,outlawed from many classes for being too efficient.
I am old guy not sure how old you are. I have experienced all the various power adders. Driven them ,ridden in them. A properly sized turbo will have an excellent wide powerband. Too small will run out up top and too big will narrow the powerband or make it peaky as you said. Depends what you want from the car. The factory often will chose smaller turbos. This gives quicker spool but costs some up top. But gives a pretty broad powerband where its useful in most street driving situations. Some guys bolt on huge single turbos or giant twins. They get late spool up and narrow their powerband.
Choices...and different purposes. /But they get monstrous high mid and top end.

You can overcam an engine, take compression way too high,you can choose wrong headers or put heads and cam on a car and not do exhaust. You can put huge heads on a car. Just mistakes in the build same thing.

I happen to own a turbo car if you check out the sig. And I guarantee that after even a short ride I will be cleaning your seat after you **** your pants from pure fear and that will likely only be at 7psi or around 750 engine hp with torque that will rip your head off from 3000 up as it hits full spool .And you would realize really quicklly that your theories about backpressure or whatever you think you know about turbos is all just theoretical mumble jumble!

I have had big cube NA, a huge roots blower BBC, cars with spray. But my 408 TT and my 97 turbo talon with its big snail are two of the scariest of all the cars I have ever had.They can be described in one world..BRUTAL! The only comparable feeling to a well done turbo car is a huge 300 or 400 or bigger shot of nitrous and the bottle runs empty! Turbos just keep going and going like the energize bunny. They would boost forever if it weren't for their wastegates.

What other power adder can make a little 1.8 4 banger put out 1000 hp?
You don't see many roots or twin screws or even centrificals doing that on those little engines. Turbos work ,plain and simple and work very well. I predict in not many years we will have turbos that have no need for oil or water cooling. Turbos that can spin up much quicker which will greatly widen the powerband. This will be turbos golden age. Science fiction..not at all...two words..magnetic bearings! That will be the new HOTNESS in turbo technology. Almost zero friction.

Anyway sorry for the novel. I guess I take my power adders too seriously.
And admitted they are all fun but really its pretty much common knowledge turbos are king of the hill.But they still can be improved on.And superchargers would also benefit from magnetic bearings.

And yes will concede one point to you .If I shove potatos in my tailpipe of my turbo car it won't run very good. Now that would be backpressure! But unless you go super small on your turbo sizing for the motor its not much of a factor in the real world..just mabye on paper or in some intellectuals head.

I think its been said that bumblebees can't fly? And of course sts turbos don't work..UMM OK!

Zombie

iTrader: (2)

Don't forget that blow through carb setups don't work either.

TS6

iTrader: (41)

I should have clarified: I meant similarly sized turbos. Your turbo is capable of alot more than my D1SC.

MY99TAWS6

iTrader: (3)

Comparing boost levels is also pretty useless as different turbos and would think different supers have very different airflow capabilities at the same boost levels. 20 psi on my stock t25 turbo is not the same flow or power as 20psi on my gt35R.
Too many guys just compare 7psi to 7psi. More to it than that.

You can of course go bigger and bigger on supers also and get more and more power.But the simple fact remains supers are not as efficient as turbos since they run off the crank
and centrificals are progressive by nature since they are tied to rpm.
Roots have great bottom and get weak higher up. Twin screw are strong all thru the powerband but still not as efficient as turbos. But this efficiency thing is not that meaningful in the real world either. Who cars if a super eats up 100 hp if it puts out 400. Still a 300 net gain and thats still huge!

It all comes down to what powerband and what a person likes. A turbo car is not automatically going to beat a centrifical car. There are lots of factors to consider driver is big one,traction, suspension,raceweight,etc.

Main thing is all the power adders work and work well and all are big fun. Just like some guys are still saying the sts rear mounts don't work. Well after having driven and ridden in two they do work and work pretty good. So again theory is one thing real world is another.

Most of us I think live in the real world. Bench racing ends at the track or dyno. Well even more the track. And high peak power is not necessarily the best . Big areas under the curve can mean a lot more. Its probably easier to mess up a turbo setup with way wrong sizing,especially way too big. Supers seem more forgiving. And the twin screws and roots sure do put out super torque down low!

sciff5

iTrader: (1)

As far as I know 20psi is 20psi if your comparing 2 different types of FI on the same engine. Boost is just a measure of restriction... although a supercharger may use more of the engines available power to turn it.. turbos suffer from pumping loses..

Lets stay on topic here.. Obviously I am talking about a properly sized turbo. We all know what happens when you put too large of a turbo on a car or too small.. no need to go over basics here. I want to get a little more in deapth.

MY99TAWS6

iTrader: (3)

Then why do turbos have airflow specs..and that airflow determines the potential hp output. A 65 pound per minute will do around 650 engine hp. A 25 pound per minute would do 250 max.
So according to that if the little one could do 25 pounds then the big one would have to do 65 pounds.
But in actual fact the big one might hit its rated power at 35psi on the one engine and the little one might hit its peak at 20psi.
20 psi is 20psi if you don't take airflow into account. PSI is meaningless except you know that going up psi on a turbo that is not flowing its max yet at the lower psi means there is more power to be had. once turbos reach their max airflow then they don't do much if you try to take them higher.

So a 650hp turbo might reach that max power at 20psi on a big engine, 35 on a smaller one.
Because of airflow being the real measure of power dont think you can directly compare boost for different supers and turbos. You would need to pick say a turbo that can do 50 pounds a minute and a super that can do 50 pounds a minute on same engine and then compare loses due to things like engine drag on the super. Not as simple as some people seem to think.

I have seen a mag test take super,turbo and compare at same boost levels.It was pretty much a meaningless test.

lcvette

iTrader: (3)

I own a turbo corvette C4 LT4 and a procharged LT4.. both have built heads cam motors.. the blower is a P1SC (baby blower) and the turbo is a 76mm.. at the same pressure level, the turbo car destroys the blower car hands down. now the thing to remember here is that the P1SC has a VERY inefficient compressor wheel. non-helical blades and it does the job but not nearly as well as a D1SC or F1a or larger would.

my take on my cars.. belt slip SUCKED for me since the drive assembly was a 6 rib belt with minimal wrap on the crank, it wasn't until i spent 2 grand on a new balanbcer and bracketry and lots of other stuff that the blower car even worked correctly. now it is a dedicate 8 rib drive with 270* of wrap.

so for simplicity sake, neither the turbo nor the blower in MY application was easy to get right. (no turbo kit for C4 corvettes, I built it myself)

for the drivers seat perspective ..... Turbo all day long.. the blower car doesn't get driven hardly ever since the other car is up and running.. nothing feels like a turbo coming online on its way to 22psi..... that Hand of God push people refer to is where its at for me!

Chris

30th t/a

iTrader: (51)

I thought this was a neat comparison
http://www.youtube.com/watch?v=a-hypgHPu14

2 stangs, 1 PT76 turbo, 1 F1A Procharger. The procharged Mach 1 6 speed needed 6 more psi to hang with the turbo auto stang.

NicD

iTrader: (7)

Looks like you are just repeating what you heard somebody else say because it's not factual information and you obviously don't have any experience. My combo is about as simplistic as you can get as it's just a stock cube motor with a average sized turbo (T76). My powerband goes from 3700 rpm to 7000 rpm as I let off early on that graph I posted and that's on a non-loaded dynojet and it's better on the street/strip. During a race I am really never below 3800 rpm nor am I below full boost.


I don't understand your point here? Of course there is exhaust backpressure that goes up when you run more boost or spin it higher, but so what? My powerband doesn't suffer because of that nor do I lose as much total power from having that backpressure compared to driving a supercharger mechanically. Do you have a point?

slow67

iTrader: (2)

Wrong!!! 20 psi on one turbo (or blower for that matter) may create a lot more heat than another. More heat=less power. Also, a blower (as stated earlier) my make 400 more hp at 20 psi, but it takes another 100 to turn it, so you only gain 300. Granted a turbo is an exhaust restriction, but will still make more power than a comparable size blower.

cablebandit

iTrader: (37)

aint that the truth.
My small incons made 735-750 rwhp at 15psi
my 88 makes the same power at 8psi so size does matter

turbos are more hassle than a s/c. Just depends on what you want. A s/c requires headers and generally a littly louder vehicle than a turbo vehicle. Turbos are a little stealthier but of course once you go to the drag strip, all bets are off. There is no BEST option....just one that suits YOUR needs/wants best.