Announcement

Collapse
No announcement yet.

turbo chargers

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • turbo chargers

    i know this isnt a racing site, but i know a lot of machinists are gearheads by nature. my question is regarding turbos. i found a unit by warner-ishi model rhb3. it is shown in a book next to a box of film for a size comparison. it is rated for .5-1.25 litre engines. my problem is i have tried to find out where or what these units come on, if i can buy one direct from the manufacturer or what. i have emailed several turbo distributors, as well as warner ishi and have recieved no responses. it seems as though you have to have c.i.a. level five retinal scan clearance to get anywhere. that is just my experience with turbos, just wondering if anyone has an "in" with a comany. any help is appreciated. i have a summer time project coming up that involves turbo charging a 400 cc engine. but it has gone nowhere as i can not locate the unit, and i dont want to use an oversized unit because the inertial mass will be too great, and lag can not be excessive

    thanks ,

    steve

    ------------------
    extreme tractor racing
    extreme tractor racing

  • #2
    Steve,

    You need to give more details of what you expect from the turbo engine, so can you define the application of the engine a little more. Can you define where you want maximum torque, max power and where you want the boost to start. Its also good to know what maximum engine rpm will be. This is the basics for 'turbo mapping' and will define the compressor and turbine ratio's.

    Don't get carried away with thinking that a turbo will be a 'top end' performance aid, one of the benefits of turbo's are that they produce power in proportion to mass through put of the engine (in other words they respond to throttle demand). This is contrary to popular belief, and as a direct result of some bad mapping of turbo applications in the past. Superchargers (when mechanically driven) produce power in proportion to engine speed, hence these units tend to give top end power at the expense of low rpm torque, which flies in the face of common concepts between the two methods of boosting.

    A good starting point for you may be to visit the following website:-

    http://www.turbofast.com.au/welcome.html

    There are some good calculators for basic turbo mapping available on this site.

    One other point to remember is that if the engine is fitted with a carburretor, then you would be well advised to fit the carburettor downstream of the turbo (i.e. as a pressurised unit). This will prevent the compressor centrifuging the fuel out at high speed, not something which is beneficial!! This does raise the problem of having a pressurised fuel delivery system which is capable of varying the pressure delivered to a float chamber, a Malpassi unit is required to do this.

    RR

    Edit note Whoops wrong url!!!!


    [This message has been edited by Ragarsed Raglan (edited 03-19-2003).]

    Comment


    • #3
      My best friend works for a rebuilder that does starters, alternators, product blowers, and turbocharges. They are pretty large into turbos. He is in charge of the turbo line. If you give me a pic and serial/model info, I will pass it on to him.
      Matt

      Comment


      • #4
        ragrag,
        thanks for your information on turbo mapping etc. i didnt mention all the details, but i have considered all of the specs etc. the reason for my post is unless it is a honda civic, people cant help me get what i need.i contacted the manufacturer directly and got no response, but like i said before, i have a picture from a book about turbos, and it shows this small class of turbos which is what im trying to get my hands on. Fyi, turbo lag should be null with the class of turbo i want to use. if i try to get away with a larger turbo, i fall out of my compressor map and will be in surge sector which is no good. obviously, lag is inherent by its nature, but because of the clutch system i am using, this is tolerable in the low ranges, as clutch slip will give a dwell where the turbo can ramp up. after this point i need peak torque through the midrange . if i have too big of a compressor turbine combo, it will just lag lag lag.this smaller turbo based on the air flow throught the motor is ideal, its mass is small, its a/r ratio is ideal, and im smack dab in the center of its map. i just cant locate them. one company quoted me a larger turbo,(2.5-3.8 liter engines,) and i just laughed. im trying to superstuff a lawnmower engine!
        extreme tractor racing

        Comment


        • #5
          Here's a couple of links that google turned up searching on "rhb3 turbo"
          Turbo 4-wheeler:
          www.paatving.com/Articles/turbo400ex/turbo400ex.asp

          Buy a rebuilt ($100 core charge...)
          www.turbo-power.com/pricing.html

          Comment


          • #6
            Steve,

            Sounds like you've got it all covered to me! Just got to go out and find the source of supply!!

            One aspect you may want to consider, if this is a competition vehicle, is doing similar to one of my colleagues at work. He races a Ford Sierra Cosworth RS500 (sprints and hill climbs), he has modified the turbo with an external electric motor drive to the compressor. This allows him to hit the switch on the dash and get his turbo on full boost whilst sitting on the start line with only about 1500rpm on the engine, and light load.

            RR

            Comment


            • #7
              rr, thats a unique one! never heard of that. im not going to go that route though. i wouldnt want to spend the money on a motor that could spin that fast, nor the engineering involved to connect it, probably need a sprag clutch or something. amazing though. what will they try next? heh.
              steve
              extreme tractor racing

              Comment


              • #8
                lunken, good links thank you. i need to get googlin.
                steve
                extreme tractor racing

                Comment


                • #9
                  Glad to help. I gave the search terms because I tried several combinations and those gave the best results. It's a trick to get Google to give just enough results, but not too many...

                  Comment


                  • #10
                    RE:........ he has modified the turbo with an external electric motor drive to the compressor. This allows him to hit the switch on the dash and get his turbo on full boost whilst sitting on the start line with only about 1500rpm on the engine, and light load.

                    My old 1966 turbocharged Corvair, 164 CID (2.69L), 180 HP compressor turned about 10,000 at idle and 80,000 RPM at WFO. How does your buddy get his electric motor to turn the compressor (probably smaller and therefore spinning even faster!) up to speed? What speed does it turn when he drops the clutch?

                    FYI the old (1982), 650cc, four cylinder, Yamaha 650 Seca motorcycle had a turbocharger and at 11 PSI of boost and the motor turning 7500 RPM the turbo was turning 250,000 RPM. That is NOT a misprint. If I recall it was that same tiny , RB3 Ishi/Warner turbogharger too.
                    Rgards,Ken

                    Comment


                    • #11
                      kgarver;
                      kinda defeats the purpose of "free"horsepower.
                      extreme tractor racing

                      Comment


                      • #12
                        kgarver,

                        It just happens that part of our business (the EV branch of our group, EV standing for Electric Vehicle) is high speed DC brushless motors, the largest of these is 110Kw 15Kg weight and run at 20,000rpm, the smaller ones are in the 25Kw range and spin at upto 80,000 rpm. We even do some smaller still that are gearchange actuators for fly by wire that are geared to well over 100,000rpm and can gearshift in 4 millisecs (faster than either pneumatics or hydraulics). These motors run on 300V and above. We did the electric hub motors for a Chrysler concept car a number of years ago. I'm afraid I can't reveal too much as a lot of this is sensitive information.

                        RR

                        Comment


                        • #13
                          It's hard help you when you play your cards so close to your chest. I can see why you've had problems getting info from the manufacturers.

                          So far we have "supercharging" and "Honda Civic" and your frustrations with directly dealing with turbo manufacturers. Nothing about cam, carburation, stock, modified, strong parts, RPM, service, reliability trade-offs; there's very little to go on.

                          Lemme give you some background.

                          People expect a lot from superchargers. The problem is, physics frequently frustrates these expectiations.

                          Failure to understand the physics of superchargers leaves you at the mercy of people who claim they do and want to either sell you one or have you buy into whatever line of nonsense they're spouting.

                          There's no-one who's taken a harder look at superchargers on piston engines than the military and aircraft engine manufacturers during WW II. No expense have been spared and experience gained is preserved in librarys. There's little theory in today's engine supercharging niche that wasn't developed in this era. Subsequent advances have been made because of manufacturing, computer modeling and new materials.

                          Airplane engines operate in a somewhat different regime than automotive engines but the information gained back when is applicable to present-day piston auto engines. Superchargers increase charge density in the engine cyclinders. The more fuel/air mixture is stuffed into the cylinder the greater the expansive force of the conbustion gas acting on the piston. There's a figure associated with this BMEP - brake mean effective pressure.

                          Supercharging increases engine torque. Period. Increased torque at a specific RPM results in increased HP in direct proportion. Since supercharging improves engine "breathing" associated benefits include a potential for effective operation at higher RPM. Increased torque at higher RPM results in HP figures to delight any testosterone secreting mammal. It's also an excellent way to scatter engine parts.

                          Supercharging may be mild or massive depending on the end use, reliability, budget, and mechanical strength of the engine. Much can be said on the subject of supercharging engines but when all is said and done self-appointed experts and ICE engineers all agree: optimizing a supercharger to an engine is ultimately more dependent on tinkering than calculation.

                          A supercharger is an air compressor and it requires power to compress air. As the weight of charge increases via supercharging the HP demand of the supercharger increases. Thus a significant fraction of the engine output is required to drive the supercharger. Nothing is free. Even the exhaust driven turbo chargers draws power normally wasted from the exhaust stream and thus increases exhaust back pressure.

                          Further, compressing air heats it. You can stuff less warm air in the same volume than cold air. If the supercharge pressure is high enough an intercooler is required for safe combustion and to take advantage of the potential power increase.

                          The increased HP to drive the supercharger comes from the engine via the exhaust back pressure. Exhaust turbine driven superchargers (turbochargers) increase their boost as a complex function of the weight of flow through the engine, exhaust heat, and a number of other factors. The potential for engine destruction from the effects of turbocharger runaway overboost is such that waste gates sensing boost pressure are installed to bypass exhaust gas thus "linearizing" boost.

                          Materials and manufacturing advances have sparked developments in recent years but don't expect miracles. If you're looking for big HP in a small engine and a pre-engineered kit doesn't seem viable, you're going to have to do some studying. If you don't understand the basic concepts it's very difficult to relaize what's possible and what isn't. If you're unable to speak the "engineering-ese" you won't be able to articulate your questions in a way busy engineering types can readily understand and respond to.

                          Manufacturers are normally thrilled at the prospect of selling their products. Denying a purchaser info is not in their interests. They may be reluctant to give you pricing information becuase they have contracts with their distributors.

                          This is not to say you can't purchase direct from the factory at a substantial discount a turbo for an "engineering prototype" but you'll have to sound plausible as a kit developer or whatever when you approach Warner Ishi.

                          As for "Zero lag", that's careless talk. You will always have lag in a turbocharger because of the rotating mass and the time taken to accellerate it. The lower the rotating mass the quicker it will accellerate to boost RPM. If the mass is low enough the lag may be imperceptable but it will still be there.

                          Lastly, adding a turbocharger is only part of the problem of increasing an engine's output. The cam, carburation, valves, racing class rules, and a dozen other parts and factors (including the depth of your wallet) have to be balanced together if you're going to gain the most bang from your engine.

                          If your HP requirements are transitory (passing, drag racing) NO2 might be a better choice than a turbocharger.


                          [This message has been edited by Forrest Addy (edited 03-21-2003).]

                          Comment


                          • #14
                            forest, i appreciate your information. let me stop you before you post another long reply. i did not need your explanation of how a turbo works, how manufacturing distributors work, how a turbo has lag, etc. i am fully aware of all the associated details. my question was finding a very small series of turbo such as the one i have seen and the associated documentation. i did not ask warner ishi if i can buy it direct, i was mereley asking for information on the said unit for available turbine/compressor a/r ratio's, draw through or blow through seals, etc. etc. no one i have spoken to can get me the info on that. i can get all the info i need for a rayjay or warner or whatever else, if it goes on a common application and the information is readily available, hence the reason for my post. i did not go into all my specifications, what size cam, compression, powerband, etc, for the sake of simplicity in my question.". Fyi, turbo lag should be null with the class of turbo i want to use. if i try to get away with a larger turbo, i fall out of my compressor.... " this is meant to mean "not relevant" for the amount of lag that would be present and the range in which it would occur for my application. i fully realize that lag is an inherent phenomena in the turbo charger. i appreciate the information on this site, just dont assume i dont know anything and dump your vast knowledge of turbochargers onto my post like you are gale banks. and to answer your last suggestion about nos vs. a turbo, not into that. wheres the fun in that? please dont take this the wrong way, but i am a little defensive when i feel like i am getting answers to questions i didnt ask, because it is assumed that i dont know anything. maybe i worded my post "carelessly" , speaking casually instead of scientific. sorry for the confusion.
                            steve
                            extreme tractor racing

                            Comment


                            • #15
                              Forrest, you took the words right out of my mouth.

                              I just want to install an Eaton M90 on my Slant Six. No I'm not kidding. I've already designed the adapter for my intake(Offy 4Bbl). I'd rather cast a blower intake to bolt the M90 to directly, thus doing away with the adapter, and a potential vacuum/boost leak. I can bolt a Weiand 142 to my Offy by making an adapter from 3/8" or 1/2" aluminum plate. But I like the Eaton's boost bypass for idle and cruise conditions.
                              Not that any of you care to hear about this. It was just on my mind.
                              Anyone remember the Turbodyne Superpac? It was an electrically driven centrifugal supercharger offered for sale in the late '90s. I'd still like to have one of those. Hmmmm, if I get an inverter and a couple of leaf blowers..............

                              Comment

                              Working...
                              X