I thinks some of you guys is funny.

"Turbos are best" no "Superchargers are best" lol.

A little secret here....A turbo is a type of supercharger, every bit as much as a roots type blower is a type supercharger.

What ever floats your boat, by all means, bolt er on and drive it like you stole it.

"Roots type blowers only make torque down low" huh? Why would the most powerful version of this combination leave the tree at 8000 rpm and go through the traps at 8500 rpm? 7500-8000 hp with a 500 cu. inch motor. Now I've been hanging at the track since I was 3 yrs old and I have not once seen a turbo car do that no matter if it was sanctioned by the NHRA,IHRA, AHRA or BOZO the clown. I've never been at a roundy round race or an Indy race but I am going to guess that a 1000 hp Indy car would whoop a 8000 hp Nitro Funny car right about the same time they came to the first corner. That would make a pretty good argument for the turbo car but not worthy of arguing over for obvious reasons.

I believe that turbos are just fine but, I like roots type blowers for what I do and to have a meaningful discussion attempting to compare one with another, I believe you're gonna have to break it down into categories. I want to say that these categories would include intent i.e. street (500-1000 hp), short duration road race/drag race (1000-2000hp), long duration road race (1000-2000 hp), and all out drag racing (3000-8000 hp). But I dont know anything about the other types of forced inductions when they're used within their intents so there is probably a lot more sub-categories that I haven't even considered.

first of all, 10psi of boost is a 66% increase in power, at sea level anyway. atmospheric pressure at sea level is 14.7 psi, lets say 15 to be more simple. by mathematics, 15psi and another 10 psi would be a 66% increase. that 1 dude that says the turbos are restricted in the NHRA obviously doesn't know that turbo lag would not produce 0-100 in .84 seconds, 4.75 positive g's on takeoff, and all the other cool **** they do. check please. oh, heat. exhaust is the hottest part of the motor, the heat transfers from the turbo shaft to the turbo, to the incoming air, heating it up that much more, besides compressing it, Boyle's law of gases big guy. more heat, intercooled maybe, but intercooled centrifugal superchargers are that much colder. next, think, a big fan in the way of exhaust gases, this means backpressure like a mother. which takes gas and horses. and if u think those systems headers they provide solve it, they don't. and cost, c'mon. dont even build a car if u dont intend to street race it. of course all this depends on your horsepower and torque curve, and why you really want your car bad ***, and how bad *** you make it, and how 1 drives. find out more facts before you start pointing the finger. dont take my word for it, u probably wont cause your arrogant for writing that article, go find out. they each have pro's and con's. neither one is necessarily "better," like constant load, turbos are slightly better. but differencing, superchargers are the way because they're output is directly proportional to engine rpm. ive written enough, some people will never learn.

There are still some diesels still in use that use roots blowers,in fact the 892 jimmy diesel used 2 turbochargers feeding a roots blower,g.m. must have found benefits in both of them,they were producing 600 hp plus,in the late 60's,when the turbod only cats and cummins were putting out only half that,keep in mind tho that the jimmy was a two stroke diesel.

I think the reason all the big deisels today use turbos is because their cheaper to produce as well as more fuel efficient.

Yeah Jim, the Detroit Diesel/GMC two strokes wont run without that blower on it either. It's the only way for them to get air into the cylinders. A big 8V92 sure sounds cool when it revs though.

Bigger two strokes like the EMD 645 and 710 series use a turbo with an overrunning clutch so when they're running at lower engine speeds the turbo is directly connected to the engine. When exhaust gas flow is sufficient the clutch disengages and it acts like a traditional turbo.

[QUOTE=Blazin72]Yeah Jim, the Detroit Diesel/GMC two strokes wont run without that blower on it either. It's the only way for them to get air into the cylinders. A big 8V92 sure sounds cool when it revs though.

I think they will run without it,just not very effeciently,I've seen blowers pile up in them,they still run,but not even enough power to move an empty truck down the road,they have to be towed,

The 71 series jimmies(also two stroke),came either blown or naturally aspirated,they would run without forced air.

I do know that they will both run backwards if you roll a truck or machine in reverse,in gear,the engine will run that way and puke all the oil out of the exhaust pipe until you trip the emergency air shutoff on the blower.

Very powerful motors,just not fuel efficient.

Jim, the Cylinder on those two strokes does not uncover the air box ports until the piston is almost at bottom dead center. There is no way for the cylinder to draw air in. At the same time the air box ports are uncovered the exhaust valves are open. The blower blows down the cylinder, forcing the spent gas out. The exhaust valves close before the air box is covered up so the cylinder can build a little more pressure.

The Detroit/GMCs are considered naturally aspirated when they dont have a turbo, even though they still have the blower on them.

They are fairly powerful for their size, considering an 8V92 is about 120-160 ci smaller than the engines from Cat and Cummins.

Don't ya just love a good debate?

But beware,I am a master debater!
As well as a heavy duty mechanic and been around deisels for a long time.

A jimmy has four valves per cylinder,all exhaust valves.
Air intake is thru slots in the cylinder walls.
The blower forces the air into the crankcase,and that is the reason the jimmies were always referred to as GREEN LEAKERS,they leaked oil all the time due to the excessive crankase pressures.

I have never been inside a 92 series engine myself,but have rebuilt 71 and 53 series,and they do come naturally aspirated,no turbo,no blower,they draw air thru slots in the cylinder walls about half way down,the incoming air is what pushes the exhaust gasses out the valves,the same way a two stroke husqvarna 2100 power saw works,and it has no blower or turbo,or no rotary or reed valves.



Air flow is what makes them work,once they fire in a certain direction,they keep going in that direction,that is why a jimmy will run backwards if started backward,with the blower actually sucking air out of the motor,and in thru the exhaust ports.
It was a common problem on the old jimmies that is one of the reasons the air emergency shutoff was built into the blower.

I can post an internal diagram from one of my jimmy manuals if you like.

Or check this out:
http://www.eng-tips.com/viewthread....d=107194&page=1

A blower on a diesel and a blower on a gasoline engine are two different animals. I don't know much about diesels, but I have a pretty good handle on blown gasoline engines.

The example of why don't top fuel dragsters run turbos, doesn't hold water. The reason is the class rules DO NOT allow turbos. The blowers are limited to a certain size as well. While they do make huge power and turn a lot of RPM these are NOT pump gas or even race gas engines. They overdrive the blowers a BUNCH. You could not do that with pump gas. With that in mind roots blowers shine at lower RPM's over other power adders. They just by nature make a ton of down low torque. That is not to say they can't perform well at upper RPM's as well, they are just at a disadvantage in all out power high RPM applications, the turbo and centrif superchargers start to shine up there.

For those that haven't been to serious drag races (Fastest street car, PSCA, Outlaw races, etc..) you need to go. You will see the blown cars 60ft much better and run the same ET as a turbo car, but you will see the turbo cars MPH a LOT higher than the roots cars or even the nitrous cars. This is because the turbos make more and more power as they go down the track, more RPM more power.

There really isn't even a debate here, there are facts and there are opinions.

If Top Fuel were running Turbos, I am not sure the ET would be much different, but I KNOW the MPH would be nuts. This is what the NHRA does NOT want. This is why they limit gearing, fuel, supercharger size, tire size, etc... They just like Nextel Cup want the races as close and as safe as possible. How much faster than 330MPH do they need to go?

[QUOTE=camaroman7d]



There really isn't even a debate here, there are facts and there are opinions.

Facts x opinions = debate.

]

name one diesel engine used for on or off highway trucks that uses a meck blower, that has been built in the last 10 years. 8v 71 and 92 series detroits made goob power at full rpm but had a ver poor torqe curve and pumped 1/2 the fuel out the exhaust. cat and cummins had a excelent torqe curve as the engines pulled down under load extemp rises and turbo speed increases thus boost increases. especially good on hills as engines get same air at 10000ft as sealevel.the fellow who has seen the 2stroke gm without a gear driven blower running has seen something rare. in the days of cheap fuel the detroits were a ok engine, did well in marine (sea level lots of air}race cars and dragsters i know little about so cant coment on. but automotive diesels ther is no contest turboes ar light years ahead

This is a hot rodder site, not a diesel site. When talking hot rods (gas engines) typically diesels aren't involved. I don't think anyone is arguing that diesles work more efficient with turbos. Not many funny cars or dragsters with diesels.

All power adders have their advantage and disadvantage. If the car is built around the power adder of choice (proper gearing, tranny, weight, etc..) all can perform well. The use and goal of the car is where the choice of power adder comes in.

I just have to say that I am dissappointed to have not seen (maybe I missed it) in this thread anyone mention the twin screw supercharger. Which is far more advanced than the roots-type. It takes what's great from roots and all is better from there.

You definately can not class any forced induction method as "the best", because all types have different advantages and disadvantages except that now the twin screw supercharger is better than the roots type supercharger at everything other than cost. From what I have seen Turbochargers and Centrifugal superchargers offer the best in all out peak power since they are the same basic concept except for what drives them. One thing I haven't seen much of about Turbochargers is how much power is loss through it obstructing the flow of exhaust if any at all. By seeing how much of a power gain you can get out of using true equal length headers against shorty headers or stock manifolds, I'd just imagine that since the wastegate has to tap into the exhaust it must block some sort of flow causing the exhaust to not be able to escape fast enough for it to flow as well as without the turbo wastegate. They say it can't have a parasitic loss due to the fact that it is tapped into wasted energy but it might if it is effecting the rate at which that wasted energy flows away from the engine for it to breath to it's most optimal. If anyone has any information or charts concerning that matter it would be interesting to know.

So given that the turbocharger and the centrifugal are the ones battling for peak power. On the other side I personally think there actually is a best forced induction system for the street with full boost almost right off idle all the way to red line with no boost drop off in the upper RPMs like with roots-type supercharger, puts out less heat than both the roots-type supercharger and a turbocharger, allowing you to increase boost, and has an incredibly low parasitic loss and that's the twin screw supercharger. Getting exhaust components ceramic coated isn't going to lower your temps it will just prevent them from warping and cracking due to heat. Single Turbochargers systems have been proven to hurt the low end power more than running NA. Some people ask well why are so many vehicles including diesels using turbochargers out of the factory. Well that's pretty simple, turbochargers are cheaper and you can bet that major manufacturers get great deals on ordering in large quantity. It's cheaper for diesel companies to purchase large turbos to be able to put out decent boost levels at low rpms than to purchase superchargers. And it's not because they want to make it easy for people to make 10second times at the drags. And theres a reason why many major brands are changing to twin screw type superchargers on their newer vehicles like the new Ford GT and many of models from Mercedes

When it comes to forced induction the turbo is the most efficient, powerful, and cheapest way to go. end of story. im sure all of you who have your roots blown 572 arent aiming for efficiency...just (easy) power. Personally, ill take a 9 second 3 liter turbo supra (with a stock bottom end might i add) over any street driven supercharged car any day.

This is what basically sold me on turbo engines...

2200 horsepower on pump gas...not to mention under 500 cubic inches...and what about upwards of 2800 hp and 2100 ft lbs of torque on alcohol?
twin turbo pontiac V8 I'd love to see a supercharged engine make near that amount of power with less then 500 cubic inches.

I'm new to all this.
I found this forum because I’m currently searching/deciding on what kind of forced induction should I use for my civic.
LoL I know its a piece of junk. and I only have a stock Integra type R swap in it.
almost stock (edelbrock manifold, top secret intake, greedy exhaust. and gsr trany with ls fifth gear (so I can cruise at high speeds on highway.)) I love doing at least 135mph on it almost everyday on my way to work (early on morning no traffic.)
no internal changes.

I'm using it as a daily driver, so I’m not looking for some crazy dragster.
my favorite part is that I get around 29-30 mpg at 90-95 mph.
I drive to work and back around 55 miles daily, highway. (my main intensions are fastlaning )

I’m interested in Jackson racing supercharger:
http://www.proficientperformance.co...percharger_kits

and here is some great info on those:
http://www.proficientperformance.com/jackson-faq.php#n


My "junk" has no exterior mods.
I like to keep it a sleeper, except the 4.5" exhaust, and integras wheels. and its lowered with teins (whole suspension kit with adjustable chamber.- expensive, but I love that cornering)

anyway maybe I’m a little off the topic.
So many opinions, and facts here.
Well look at those links; see what "Jackson Racing" made with a stock GSR,
and their 6psi (base option) blower.
I know this is just a childs’ toy in comparison to some blowers mentioned here, but is there a turbo that would make so much power out of 6psi?
I'm looking for safe for motor daily driver.
I also found a used JR blower on e-bay for around $1500 with everything needed. (pulleys, belt, fuel rail, injectors, fuel pump, and regulator. etc.)
I'm not planning on touching my internals for now.
yet
motor has around 4k after rebuilt. soooo.........

anyways I'm still deciding for if I should get a cheap turbo kit,
but this looks prity impresive to me.

any ideas? please post.

Whenever I get anything I'll post it here.

Sorry for I'm so off the topic, but I actually took the time to read this whole forum.
Too many opinions, facts and calculations based on assumptions. Too much error percentage. And since a b18c1 GSR was mentioned here already I thought of mentioning my b18c5. J

p.s. looking at this particular charger, I want to know how reliable will it be, and is there a better way I should go? I’m a big fan of turbo’s, but this one’s pretty impressive.

I am still a sc fan due to the simplicity. Some things this write up did not talk about was lag, boost creep, extra plumbing,. It's an issue with the turbo stuff. I know that you can use smaller turbos, change A/R, retard the timing at launch with your ECM to reduce lag, but that is still real technical. What about the extra heat on the exhaust manifolds. I know some of the high end turbo racers are changing their $2000 exhaust manifolds after 10 to 20 passes. Exhaust valves also take added abuse. Due to the turbo actually spooling because of the expansion of the exhaust gas (combustion occurring in the exhaust manifold) they take alot of added heat. Stainless valves is a must unless you can afford inkinal. I also think that this is a very one sided opinion and they both have alot to offer our industry. When articles are produced I feel that they should be as neutral as possible so you let the consumer decide. They ragged enough on sc so I had to on turbos. I do like them and would put one on my vehicle if it ever fits the theme of the car I'm building. I like the supercharger better for most of my applications. Turbo's are the future so we must embrace them. Also I don't recall who said this about needing twin turbos, but there are cars out there making 2000 plus horse with one turbo. Through what research I have done 2 turbos is a waste. If you tune your engine management system correctly and you size the turbo accordingly you should never need more than one.