| Author |
Message |
steve souza (Stevebnut) (24.91.90.28)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 27, 2002 - 8:04 pm: | |
Is it possible to increase the blower speed to boost power on a detroit two stroke?
Steve |
Geoff (64.1.0.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 28, 2002 - 10:02 am: | |
Changing the gears for faster rotation won't help you (if you can even find them!)-- the blower is actually an air supply pump to the engine and the stock gears already supply more air than necessary at sea levels. The usual remedies for more power are advanced timing and bigger injectors, or going to a turbo engine.
--Geoff
'82 RTS CA |
Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 16, 2002 - 5:39 pm: | |
I can see where you are coming from with this. The hot rodders years ago started hanging Detroit superchargers on their mills and simply adjusted the blower speed to regulate the boost.
Why this would not work on a Detroit is unknown to me. If just a few pounds of boost to feed the ports works fine, what would more boost do? Kinda like hanging a turbo.....
Only just the Roots type blower would be spinning faster to provide the necessary or desired boost increase. There has to be someone who hops up Detroits who can answer your question. Might be a trick way to increase some power. Good luck. |
Jason Windecker (198.81.26.174)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 16, 2002 - 6:05 pm: | |
The reason you cannot simply turn the blower faster is because the blower is simply blowing air thru the engine. the roots blower is filling and scavenging the exaust from the engine, the 2 stroke is open to atmospheric pressure when the pistons are below the intake ports, so there is nothing to build pressure against, in a 4 stroke the exaust valves are closed and intake valves are open so there is a chance to build pressure against the exaust valves, so a supercharger will efectivly increase pressures, however in the 2 stroke pressure is built against the airbox and intake ports with the roots blower but as soon as the piston falls below these ports everything is once again opened up to atmospheric pressures and all boost is lost, the piston is the only thing that will build presure in a 2 stroke, in theory if the timing was changed so that the exaust valves were closed for a time before the piston covered them then your theory might work, however the engineers at detroit have there timing specs and thats how they were desiged to work, there is no free ride here i'm sorry you might as well opt for the turbo engine and save yourself the headache as the time effort and $$$$$$ spent to accomplish this engineering feet would be better spent retrofitting to a more modern turbo engine not to mention the fuel economy lost to pumping all that air for nothing, a turbo is free boost, if it was cost effective and worked well then they would have done it, no need to reinvent the wheel, Just my 2 cents worth.
Jason windecker
21 years young and cant decide what bus i want yet LOL, |
For the greater good. (12.94.4.89)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 17, 2002 - 10:57 am: | |
Jason, good points. But could you get that period key fixed? LOL |
Greg Roberts (Gregeagle20) (172.141.251.61)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 17, 2002 - 3:45 pm: | |
Jason,
In relation to what you are saying, would you like to explain why a turbocharger is effective at creating boost (through the blower) but increasing blower speed will not increase boost? I would have to contend that boost is boost no matter which device develops the boost. It's a matter of the mission and goal of the engineers which for the detroit 2-cycle is reliability and availablility with reasonable power. The turbo is a cool way of meeting the goal. Turn the blower up and you get less reliability because it is turned up all of the time. The turbo is load sensitive so not boosting hard all of the time and is easier on the engine. Maybe you know something I don't about the physics of the design and I am anxious to learn. |
Mallie (65.38.24.92)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 17, 2002 - 4:54 pm: | |
This is a question that has been pondered by many of us who have some knowledge of how a engine works.
And I still do not see why it is not feasible to a degree, with some combination, with high compression pistons, or maybe low, std or adv. timing.
It would never be equal to the natural altitude compensation of a turbo.
My conclusion is that it has probable been tried with a lot of other schemes, and fail.
I would have to believe, with all the years of experience, DD has done the most they can with the engine, if it could have been done, DD would have done it.
Mallie |
Jason windecker (198.81.26.174)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 17, 2002 - 8:57 pm: | |
Ok boys now all this is in theory and just kinda goes with logic as to what the engione is trying to do, In effect yes you are right it does not matter what device is creating the boost, the turbo works well do to the fact it is simply using waste heat and air from the engine exaust. and making up for atmospheric conditions that are less that favorable, IE above sealevel, the roots blower could do that as well, but is far less efficient cause it takes HP to do that, the turbo is all free, the roots blower on a detroit is in essence not necesary at speeds about 1300 rpms. the turbo provides all the air, the turbo is better at creating boost because it is more sensitive to atmospheric conditions du to the fact is has much less to do with engine speed that a supercharger, yes it takes the engine running to produce that but still less reliant on engine speed but more on heat exiting the engine< where as the supercharger is always relying an the engine to be running at a specific RPM to acheve boost, (if it were set up that way) so yes now that i think about it in theory it would work but not cost effective, just like i said in last posting if it were effective DD would have done it, just my 2 cents worth again and goes along with the whole theory of engine operating principals, get a turbo LOL jason windecker |
Richard Bowyer (Drivingmisslazy) (66.190.119.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 17, 2002 - 9:16 pm: | |
Jason, your posts would sure be a lot easier to read and understand if you would be so kind as to include a few periods and paragraphs.
Richard |
Jason Windecker (198.81.26.174)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 17, 2002 - 9:34 pm: | |
Sorry guys i am through with school thanks, however whan i get on a thinking rampage thats the last thing that comes to mind will try to do better next time, you all know how that goes
Jason |
Gary Carter (66.82.52.49)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 19, 2002 - 12:30 am: | |
I never noticed the lack of punctuation. |
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