The “Redneck Blower”, fact or fiction?

Discussion in 'Rally Raid' started by J.D.., Jan 17, 2012.

  1. J.D..

    J.D.. Member

    Joined:
    Jan 17, 2012
    Location:
    Belgium
    Since this is my first post here on RDC I’ll better start by introducing myself. Late forties male, European but not French(Belgian to be precise), and involved in amateur and semi-pro motorsport since my late teens, and this both in rally(wrc style tarmac and gravel) and track(touringcars and GT’s). Apart from this I also have a big intrest in the Dakar(most WRC fans don’t really care for Dakar, they consider it to be a not very competitive adventure sort of event), and i found this site years ago when Robby Gordon started campaigning his Hummer, it was about the only place where i could find some info on the driver and the car. Since then i’ve been a lurker here, and even became very interested in American off-road and bajaracing. I’ve followed the last couple of Baja1000 live on my pc, included the wheaterman audio feed. And no, I stil don’t like TT’s or any other sort of racetruck(they just look wrong, must be a cultural thing i guess:) )but those class 1 and 10 buggy’s are extremely cool. Up till now i never posted a message here because i didn’t feel that i could contribute much, there’s more then enough knowledge available here, and posting some euro insight to counter some of the misconceptions here never seemed worth the while. Others sometimes try to put some things in perspective(e.g. Mark Miller) and although most seem to respect his views, I often have the feeling that they dont take them into account very much.

    Now about the “Redneck Blower”

    Well, what i’m gona write here I figured out about an hour after hearing the RG got Dqed for plugging his in/deflation system into his engine inletsystem bypassing the mandatory airrestrictor.
    The reasson i’ve waited this long is that i thought someone else would also come to the same sort of reassoning and post it here so i wouldn’t have to(writting in english is a slow and very tiring activity for me :) )

    Before i proceed please understand that i’m not saying that Robby cheated, i only want to discuss the fact that there’s more to this than first meets the eye.The one’s who could know(Fly??) have been very scarce in their info about Robby’s CTISsystem and only throw us a “red haring”, being that the air stored in the spare tyres is no more than a “mouse fart”, a fact i easily agree with.

    Now let’s look in detail what a CTIS system really is. In the middle there’s some sort of manifold with valves and pressure regulators(manualy or electronicaly controlled), and on the one side this is connected to the tyres(only rears and spares as per ASO/FIA regulations) and on the other side there’s a pressure source(compressed air bottle and/or compressor (12volt or enginebelt driven)).The rules allow for a 15liter(0.53 cuft) bottle, a 300bar(5000psi) bottle can thus contain 4500liter of air(159cuft). Checking some simple compressor specs i found that a 1hp compressor delivers 100liter per minute, a 2hp compressor 200liter per minute, you figure out the rule of thumb yourselvesJ. This means that a 1hp compressor can fill this bottle in 45 minutes, or 22.5 minutes in the case of a 2hp one, and so on. But how much can one do with 4500liter of air? The stoichiometric air-fuel ratio for petrol is 14.7, this means that for a given mass of petrol you need 14.7 times that mass to burn or combust the petrol. Now some simple math. 1 Liter of petrol weighs 711 grams, so you need 711grams times 14.7=10,452grams of air to combust this 1 liter. The weight of air is approx 1.2 grams per liter. 10,452/1.2=8,710 liters of air needed to combust 1 liter of petrol. Well, in the light of that, 4,500 liters doesn’t look that much, just enough to combust ½ liter, a little more than a “mouse fart’, a “horse fart” maybeJ.

    Or is it?

    Please note that what I’ve written up till now is just simple facts and fysics, it describes what the rules allow for and the math and fysics of combustion. What follows now is not “fact” it’s just a little mental freewheeling,

    Ideally we would have the flow rate numbers of the restrictor, we could then calculate how much air is used and how much “boost” could be produced by adding some extra air. Another way of knowing how much air can pas through the restrictor is if we would know what the max fuel consumption is because this will be determinated by the amount of air that is available to combust it. Since I don’t have these exact numbers I searched for some info on the size of his fueltank and how much distance or time this would allow for. But in al fairness it is almost impossible to determinate this exact number. So I base my case on the high number of 50liter per 100km, and also that the average speed on the special is 120km/h. This results in a fuelconsumption of 1liter per minute. Please note that this is a very high number and that the real number is probably lower, and that the lower the number gets the bigger the described effect will be. In the case of 1liter per minute you would thus need 8710 liter of air per minute, the 4500 liter bottle would thus allow you for a 10% boost for a duration of a little over 5 minutes, or 20% boost for about 2.5 minutes, or… With a 1hp compressor you could refill in 45 minutes resulting in a 10% boost for about 10% of the time, a 2hp compressor for a 10% boost for about 20% of the time, and so on…. Imagine the availability of this sort of boost during the last couple of miles to a 12000ft summit, or climbing one of those gigantic dunes?


    Now how do I quantify the “advantages’ that such a system could generate? Well, this is a sport where hundreds of thousands if not millions of dollars get spent to find an extra couple of seconds over a 500km stage, so you tell me?


    To end. Like I said, I don’t know if RG did it or not, even more I would rather not discuss that in this thread. And what about ASO first allowing it and then dqing him for it, well, that to could be a very interesting topic for another thread. The only thing I wanted to say is that plumbing a ctis into the engine-inlet, bypassing the airrestictor could be used for more than simply using the vacuum there for faster deflating tyres. And btw, if I wanted vacuum for deflating I would rather use a simple vacuumpomp(as used in diesel-engined cars for the brake booster) anyway.


    Regards,

    J.D.

    PS. Please excuse me for my bad spelling and grammar, I live in a country with 3 official languages so English is only my 4[SUP]th[/SUP].
    3 people like this.
  2. randy s

    randy s Well-Known Member

    Joined:
    Jan 10, 2007
    Location:
    el cajon, ca
    i thank you for your input and i'm not smart enough to question your points you brought up. but i do know that the aso should never have approved the design in the first place after it was submitted to them and to come in only after rg won a stage with this is chicken chit. i also apologize for my misspelled words but if i spell chicken chit correctly i face being DQed on here. welcome to rdc...
  3. wessen

    wessen New Member

    Joined:
    Feb 27, 2010
    Location:
    high desert BELGIUM
    amai, das nen helen boterham...
  4. J.D..

    J.D.. Member

    Joined:
    Jan 17, 2012
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    Belgium
    Goh, valt wel mee:) het int engels uitleggen is het moeilijkste deel...
  5. randy68

    randy68 Well-Known Member

    Joined:
    Jan 21, 2009
    Location:
    Chino Hills, Cal.
    They talkin 'bout you randy...Hmmm??? Ha!
    1 person likes this.
  6. J.D..

    J.D.. Member

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    Jan 17, 2012
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    Belgium
    Not really:)

    Just some local "patois" between Belgians.
  7. randy s

    randy s Well-Known Member

    Joined:
    Jan 10, 2007
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    el cajon, ca
    let em' talk..i got some pretty thick skin on me. i've been a purple section member for quite awhile now. ja ja
  8. randy s

    randy s Well-Known Member

    Joined:
    Jan 10, 2007
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    el cajon, ca
    and i apologize for any mistakes in spelling here by yanks in english because it's our third language now as well after spanish and vietnamese....fourth, if you count arabic.
  9. wheeli

    wheeli Funny Guy from the North, eh

    Joined:
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    Location:
    Stifflers moms house
    The waffle guy makes some good points. Its all sh!+ head nassers fault......grrrrrrrrrrrrr
  10. Ferrari333SP

    Ferrari333SP Well-Known Member

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    Farmington, MN
    jajaja, waffle guy. When I was in Brussels for a few days back in 2008, I had myself some waffles, and they were quite delicious.
  11. michael_loomis

    michael_loomis Babe

    Joined:
    Jun 27, 2001
    Location:
    Murrieta, Ca.
    Thanks for the well thought out post JD!

    If there is a diaphragm as claimed, all that would be for naught. I don't see where the diaphragm would be though, unless the tires are tubed and the wheels have secondary stems.

    I'm certain he lost way more than 10% would have given him at high altitude, where as the TDI engines suffered nearly nothing. Could be a potential gain going up dunes however. He did win with 15 mins to spare without it connected, although his only time getting stuck was with it disconnected too.
  12. Suhaib Kiani

    Suhaib Kiani Active Member

    Joined:
    May 31, 2011
    Location:
    Islamabad, Pakistan
    JD, Nice to meet you! Good to know that I am not the only alien lurker around here :)

    I do accept the point (made on the forum) that "air after the restrictor is air after the restrictor" and something not to be taken lightly in FIA events. So that leaves Robby pretty exposed whenever they found it....

    Nevertheless, I just can't get my head around how a 3hp compressor with a bottle can provide 20% / 10% or even 5% boost to an engine easily producing excess of 400HP (post restrictor). We're talking at least 20 to 80 HPs incremental power here which if possible should make a good case for taking off turbos and superchargers and going for 10HP compressors and large air tanks! Or am i missing something here.....
    1 person likes this.
  13. J.D..

    J.D.. Member

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    Jan 17, 2012
    Location:
    Belgium

    If by "diaphragm" you mean the "manifold"(pneumatic control unit seems to be the official name for that part) well of course there is one, one might consider it the heart of a ctis system. Also there is no need for secondary stems(they are not even allowed per FIA rules), the tube just goes on the normal stem and opens the stemvalve, the pressure is then controlled by the pneumatic control unit.

    Like i said, this would not be a "double your power all of the time" kind of system. In the case of a 10% boost at 10% of the time this would only be an 1% gain on average. So not a huge gain, but not negligable also. And if used in that way it would without a doubt be illegal. And believe me or not, i've seen bigger names do weirder stuff for much smaller gains.
  14. Wendell #527

    Wendell #527 Well-Known Member

    Joined:
    Jul 25, 2007
    Location:
    Oak View, CA
    JD that is good insight. I was thinking he'd have to be deflating his tires to add hp, but I get it now. I didn't realize they had a bottle of compressed air to pull from. Still, for them to allow it and then DQ after he started winning is really weak. Changing their minds would be ok, just tell him to unhook it. To change their minds AND DQ him for it is 'tarded. It did add a lot of drama though, and probably boosted interest in the US. To see Robby smoke em after he was pissed was pretty epic.
  15. J.D..

    J.D.. Member

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    Jan 17, 2012
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    Belgium
    Well, passing FIA scruiteneering doesn' mean that the car is legal, is just means that they didn't find anything obvious. Also, the biggest part of scruiteneering is about the safety features, the technical legality part is mostly taken on face value. In the very high end racing series like WRC the technical controls are much more in detail, in WRC they even have surprise "car weighting" in between stages, the have a custom built scale on a trailer for it. And guess what, in the french WRC round of last year FIA dqed a semi-works Citroen(in third place when dqed) for coming up short 4 kg on one of those surprise "weightings". Yes, a french car, in a french rally dqed by FIA. "Merde" happens, even if your french:)
  16. Ramsey_ElWardani

    Ramsey_ElWardani Ironman

    Joined:
    Apr 1, 2001
    Location:
    Carlsbad, CA
    There was no bottle of compressed air. The spare tires act as the air reservoir and an electric pump keeps them inflated, no where near the pressures a bottle can handle.

    If you look at available pictures, you can see the CTIS hoses, and that the connect to the tires' (sp? lol) valve stems, which have valves in them. We have all deflated a tire by depressing the valve stem valve - do you really think there is enough air flow through a valve stem, even if the spares were inflated to 110 psi, to super charge a V8 that is already pumping lots of air?

    Good write-up J.D. but something is missing - and few know what it is.
  17. J.D..

    J.D.. Member

    Joined:
    Jan 17, 2012
    Location:
    Belgium
    Dear Ramsey,

    Why would one rely only on the spares as reservoir when the rules allow for a 15l bottle? This would mean that after two punctures you would be left without reservoir. And just because you don't see the bottle on some pictures doesn't mean it isn't there, that bottle can be placed anywhere in the car for weight distribution reassons. And yes i know that i'm only guessing, but that could be easily fixed by comming clear and publishing the installed ctis in detail. FIA won't do this right now because of the pending appeal.

    Best regards,

    J.D.
  18. pappawheely

    pappawheely O.G. Photo

    Joined:
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    In the Dirt
    Any additional air would have to be matched with additional fuel right? Wouldn't that detract from your effective range?
  19. J.D..

    J.D.. Member

    Joined:
    Jan 17, 2012
    Location:
    Belgium
    True, but as i said, we're talking about an on average 1%, maybe 2, gain, so an extra gallon per 100gallon. I think the Hummer can manage that sort of extra weight.
  20. arqangel67

    arqangel67 Well-Known Member

    Joined:
    Oct 24, 2008
    Location:
    Crestline,Ca
    J.D. you bring up some intersting ideas and calculations but as Ramsey has stated there is no compressed bottle of air. If there was than he would not be having these issue's with the aso. All we know is that Robby was using the spare tires as a resevoir. He had means by compressor to refill tires but not to deflate them. A vaccum pump would have created more parasitic drag on the engine and would have been another item that could've potentially failed, so my guess is that he chose to use engine vaccum (if approved which it was) to deflate the tires faster. Your calculations are pretty good but that is only for 1 liter of fuel his engine is 7 liters which would require alot more air than even a 15lbs. and tires combined could supply.

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