I think feral is right! After reading all points of veiw i have learnt more than i expected to! I'm so glad i became a member of this prestidious club, you guys are so cool! i value all of your points of veiw and i'll say this-THANK YOU! I think i will look at a turbo setup but the $64000 question- where do i start? I had a look at the section that somone mentioned earlier(tech section) and relised that there is so many options open, which one is the best? i rang the fella that i bought my 1200 ute off and he said that a sunny manifold without the hot box(somthing to do with the pollution gear, i think) is where he started and he has made it all himself(manifolds and all the plumbing), it looks rough as guts but, gee whiz it went well. Is a sunny inlet manifold were i start? and what size turbo do i need? my mate has a ET pulsar with a T2 air research(i thought they were used in chopers and light planes?) would this be big enough? the fella i bought my ute has a T25 garett(i think) and is running a side draught webber, thats another question!, what sort of carby is better because he said that he originally had a SU but had problems but since he put the webber on he has no problems, My quess is that it would depend on how the carby is jetted, does that matter?Also, do i need a cam? and which way is the best way to drop the compression ratio? a spacer plate between the head and head gasket or putting in de-compression piston and rings? THANKS again for sharing all of your knowledge and expirence, KEEP IT UP!!!

has anyone got a turbo set up? even a couple of pictures would do fine! just so i know what i'm in for.

Steve.Give Adrian a ring on 38491150.If memory serves me correctly he had a turbo setup for sale some time back,he may still have it.Hope this helps.
Jim.

Hey jim, how you doing? thanks mate i'll give him a ring tomorrow!

Simmodat
Thanks for the "robust debate"
For the record, i went back over my posts in this thread & could'nt find where i was supposed to have used the term "underboosted" Must have been someone else.


In the event that anyone is not clear, i also did say that boost is usually described as being manifold pressure ABOVE AMBIENT [pressure]


Next, there are basicly two types of mechanicly driven supercharging. Positive displacement, represented most often by the Rootes & vane types, & "other," which is usually seen as centrifugal or axial flow types. All of my writings refer to the positive displacement types, as this has been writen many times in my posts.


Boost at idle? It strikes me as a contradiction in terms. The dump & burn system [anti lag] keeps the turbine up to speed, but it does not produce boost at idle, but, like a real blower, it will allow boost to be produced OFF IDLE.
Anti lag. The very name is an admission that there is a problem to be addressed.

The positive displacement types take a fixed & measured chunk of air with every revolution & shove it down the hole. This is controlled by the variable restrictor plates on the inlet side of the blower. These plates are the throttle plates of the carb[s] At engine idle, these plates are closed, allowing only enough fuel & air to pass to sustain idle. As these throttles are opened the blower can get a bigger chunk of air. If the throttle is open wide, the blower can easily stuff more air into the engine than it can swallow. Result? Boost, right OFF idle [speed] This can result in high torque figures at speeds much lower than your average turbo instalation can provide at the SAME LOW speed.


Turbo's have been around since the 40's & formalised drag racing since the 50's. In all that time, just about every idea known to man has been tried, including bottled air, through a throttleable regulator, to allow boost without a blower. Turbos have not proven to offer the performance characteristics that are required for THIS FORM of competition. The Fuel Rail engines that you refer to are "stock block" derived. That means that they are derived from passenger car engines, using a technology dating back into the dawn of the 20th century. Stuff like rocker arms & 2 valves per cylinder. The Blower that they use dates back to the 1930's. & it's design goes back into the 1880's


F1 tecnology is constantly being updated & the power outputs that they make are truly awsome, but i don't think i will be seing any F1 derived engines on the street anytime soon, even in a heavily detuned state. There are, however, plenty of 2 valve, rocker arm motors around in all sorts of configurations & sizes. It's an appropriate technology for street use.


For street duty, the linear power delivery of a [positive displacement] blower can truly enhance the driving experience, in engines big or small.


I will stop offering an alternative view on supercharging when the turbocharger "propaganda" stops.


Did i know that a turbo engine responds better when traveling up hills? Better than what? Better than when on the flat? You write that the turbo builds more boost [than what?] more quickly [than what?] A blown engine will "lug" right down into rpm levels that turbo engines start losing efficiency at. The turbo is just a centrifugal blower & it's efficiency is dependant on the impellor spinning at a satisfactory speed. Mechanicly driven centrifugal blowers suffer the same problem at low speed.


At lower engine speeds, that are often seen on the street, the exhaust volume is less, & as boost drops off, it becomes even less still, & the turbine starts to lose speed. One feeds the other & it becomes necessary to increase engine speed [lower gear] to increase gas flow, which spins the turbine, making more boost, resulting in more gas etc. etc. The ability to benefit from the boost provided by a positive displacement blower at LOW engine speeds is NOT a bad thing.


You seem to know a lot about Iraq, & i don't know what you are on, but VB does not help preformance.


Turbo lag, & cost, have prevented them from being universally addopted on production cars, although the many millions of Dollars that have been spent on research have definately made inroads in that department. From my own observations, the most successfull ones seem to have very complex & costly instalations of computer control, multiple turbo's & a lot of complex plumbing. EFI is also a bonus for any engine.


The technology of a positive displacement blower is simple by comparison to the latest turbo setups & killing cylinders to keep fuel flowing into the exhaust to maintain turbine speed really works, but the cost in resources & cash will keep it off the street for a while yet.


You may note that i keep refering to the STREET, which is where i live, in an automotive sense, & exotic competition stuff is beyond my reach, or desire. I would suggest that on average, almost every member here drives at least one street car, but relatively few of us compete, so i put it to you that the higher end of turbo technology, the stuff that really works, is in reality, out of reach of many. The performance characteristics of relatively simple positive displacement blower is WELL SUITED to street driving.

In conclusion, i suggest that the book "SUPERCHARGE" by Australian, Eldred Norman be sought out at swap meets. This 1970 publication addresses the problems of various types of supercharging, & although a little old, the laws of physics have not changed & it is still relevant. My copy cost me $1, so it was a good buy.

Please note the closing sentence of my post of 18/11/03
Chris

That was beautifully put
Thats all i wanted to hear from you, a nice technical explanation, well done!

Quote:

Yes better than on flat road.

Quote:
i understand what u r saying here. However, the turbochargers have not seen the R & D of recent times ever before, they are more capable than their predecessors have ever been in the past. By this i mean theyre more responsive, reliable and efficient than before. I thought by now you would have taken their ever growing presence on production cars as a sign of a change in trend, or atleast a viable alternative to superchaging, not saying a replacement, i believe supercharges have a place on the street too.

Quote:

correct me if im wrong, but wasnt this you?

Quote:

But think of this for a moment. When a drag car sits at the line, usually the engine is stalled up for a launch to a higher RPM, which means lag is insignificant once the clutch is dropped, this is open to correction. If turbos were really proven to be a "limp banana off the line" then how would you explain a performance rotary or any turbocharged drag racing vehicle for that matter being able to lift the front wheels? If what you say is true, then surely they would just putt along until the turbo reaches sufficient speed to make enough boost, no wheel stand. If this was just a joke then fine, but it got my ticker tocking

I dont hate superchargers or the people who drive them, i like fact i love the idea of diversity. After all, isnt variety the spice of life?

P.S.
Dont take offence mate, just trying to spark some controversy, makes things a little more interesting

Simmodat
I thank you for your reply & like Feral said, no offence taken. I tend to get a little "passionate" about some subjects & this is sometimes reflected in what i write. I can not be accepting of my own flaws, & critical of the same things in others without being hypocritical. If we can keep personal insults out & stick with "passion" & some minor ragging, then i'm fine with that.

Yes, i am aware that there are more turbo cars around than ever before. I am also aware that the industry had a fling with them a while back in the 80's & largely droped them from their lineup. I think the larger part of the problem lay with the high level of warranty claims. Not because turbo cars were defective, but because revheads flogged the ring out of them from new.

I will accept that the term "limp banana" might create an image that is not entirely accurate, however it did serve the purpose of stimulating robust debate.
At no load, it does not take much to bring an engine up to launch rpm, but at no load, there is not a lot of gas volume, so the turbine may well be spinning up a bit, but usually not at the speed needed to provide full boost when the clutch is dumped. The blower will deliver full rated boost within one revolution of the blower at the sorts of engine speeds that racers launch at.

Street engines can have pretty much the same thing at street speeds, but it might take two revolutions.

Turbo race engines, like non turbo race engines, bear little resemblance to what we actually drive on the street. [well, most of us] The Mazdas launch with wheels airborne because the car, the engine & the driving style are optimised for this style of racing, & if you inject the nitrous onto the turbo's blower impellor at the right place, at the right angle, with the right pressure, at the right time, then turbo lag is measured in milliseconds

Well, between us, we seem to have taken up a fair bit of space & i have enjoyed it. I also have learned something, & i am very glad that Feral decided to join us. I was begining to think i would be subdued under a rising tide of turbo technology. Arrrrgh!
Chris

As an asside, see if you can learn of the diferent application of turbine technology that was applied to the Wright 18 cylinder aircraft engine, known as the Wright Turbo Compound engine. It was mechanicly blown & the turbines pumped their power straight to the crank, thus adding 20% to the engines output & making the Constelation airliner a true intercontinental traveler.

If you ever get the chance, go for a ride in a "blown" car. It's addictive.
Chris

most if not all S/C setups i have seen are suck through, is there an issue with blow through??? was discussing it with someone and i think it would be better to go blow through but i may be missing something???

i have a blow through turbo setup, its a fair bit easier than you would think, but can get pricy, if you can make your own plumbing its a big bonus, check out some websites and look at suck through vs. blow through, that would be a good starting point, i prefer blow through but not every one does, suck through is alot simpler

basically blow through the turbo is before the carby and blows air into it, suck through it is after the carby and draws air through it

RC1200
Most "superchargers" are mounted to the inlet system at the blowers outlet flange, so a blow through design is not a practical. There are exceptions, but not many.

Turbo's, on the other hand, are usually mounted on the exhaust system & use plumbing to feed the inlet. This makes them much more suitable for use with blow through systems.
Blow through is, in theory, every bit as good as any other system, but they are not widely used, & i believe that there is a good reason.
They are a pain.

The system simply uses a box that is sealed, with the carb inside & the compressed air is blown in. The fly in the ointment is the word "sealed" The box usually has a removeable top & this must seal tight. The carb sits on the bottom, with a gasket, & the whole thing sits on the manifold, with another gasket. There must be provision for a throttle shaft that push pulls, or rotates, or a cable. This must be sealed too. Blown engines need choke when cold, so provision must be made for enrichment as well. By my count, thats 5 potential air leaks so far, & thats just the box.

If you use the original fuel pump, then that has to go in a box as well, & it must be supplied with air at boost pressure. You need to seal not only the box, with it's cover & two hoses, or pipes, but the rocker arm that works it as well. If the diaphram leaks, it is a good idea to find a way to harmlessly dispose of the fuel instead of allowing it to build up in the box.

All of these seals must be checked periodicly, particularly where a moving part passes into the box, like a throttle shaft, as the sealing medium is much more prone to leakage due to wear.

If you use an electric pump, it should have a pressure rating that equals max boost, plus whatever it would have had on an unblown engine. If you use a lot of boost, then the high pressure of the pump may overpower the needle & seat causing flooding, when low or no boost is present.

With a suck through, just mount the carb, hook up the controlls, connect the plumbing, use whatever pump you want, & drive.

It's odd that you don't see a lot of blow through systems around.
If you can make one work, it should work well, but suck through's work well to, with a lot less hassle.
Chris

Dodgeman dude, I had to read that in parts at a time.
You didn't include references and you forgot to add in your bibiography and rationale.

( I miss schoool..not)