Off Road Toad Posted January 10, 2012 Share Posted January 10, 2012 Is this wise? I'm not connected with this, i just came across it as you do. http://www.ebay.co.uk/itm/Eaton-M45-Supercharger-kit-Land-Rover-200-300Tdi-engines-/160709770184?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Car+Make%3ALand+Rover%7CCars+Type%3A2.5+Td5+4WD&hash=item256b0c7bc8#ht_720wt_1185 What possible benifits would you get from supercharging a tdi over a turbocharged one? I'm not how they've done this but they must have kept the turbo aswell as it's required for controlling the fuelling through the pump isn't it? Quote Link to comment Share on other sites More sharing options...
jad Posted January 10, 2012 Share Posted January 10, 2012 no turbo lag, cooler intake temps if you were to get rid of the turbo probably. it may well have a dent on your fuel consumption depending on how well set up it is. U could get rid of the turbo as the fueling is only controlled on boost pressure which the supercharger obviously still does. I cant imagine it would be too hard to knock up a frame like that to mount one and there are plenty of those superchargers on ebay Jad Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted January 10, 2012 Share Posted January 10, 2012 There's a reason diesels are normally turbo charged and not super charged. IIRC it's something to do with the way that a turbo is able to vary boost depending on engine load and not rpm. Higher load = higher velocity exhaust gasses = more boost etc. A supercharger's boost is entirely dependent upon rpm. Or something like that - I'd have to go and look it up. I'm not convinced a supercharger can just be bolted on in place of a turbo - I'm sure there's a lot more to it than that. Alongside a turbo (as in the eBay ad) might be a good idea for a racer (minimal lag), but I can see it having an enormous impact on fuel consumption. Quote Link to comment Share on other sites More sharing options...
jad Posted January 10, 2012 Share Posted January 10, 2012 you would have to find out how much boost it was producing at what rpm. If 1-1.2bar at 1000rpm all the way to the red line then it would go like stink but might be hard to cruise with and possibly destroy fuel consumption. There are some hot rods that meet at a cafe near me on the first sunday of the month. When i was there last there was a V8 supercharged diesel. He said he could sit behind lorries and get 40mpg so it is doable but might require some tweaking. Maybe ill have to go and have a chat with him... Quote Link to comment Share on other sites More sharing options...
Team Idris Posted January 10, 2012 Share Posted January 10, 2012 Ooooh, supercharging and turbo! Best of both or worst? I don't know as I'd fit both, but there are plenty of double turbo projects out there, so why not? If it was to reduce turbo lag it would definately need a charge cooler rather than an intercooler to get the full effect. The only supercharged Diesels I've seen have been Detroit Two Strokes in Terex plant. Isn't there a diesel two-stroke Yenbach (Turner) aftermarket engine for the S1? I guess that would have to be supercharged as well? I can't think of any major reasons why compression ignition or spark ignition would have major different responses to supercharger rather than turbo. You get more exhaust with more fuel in both. We went to a seminar where a bloke talked of an electric turbo. We wer'nt convinced, but a turbo with an electric spin-up would be neat. Quote Link to comment Share on other sites More sharing options...
jad Posted January 10, 2012 Share Posted January 10, 2012 there are standard manufacturers cars that already have both a supercharger and turbo. They are probably slightly more refined than the above example though. The SC V8 diesel hot rod i saw did not have a chargecooler or intercooler but it did have a bug catcher scoop so constantly taking in cold air. I have heard that that electric turbos are on there way and give zero lag but have no first hand experience with them. (imagine they would be slightly more advanced than the things you currently get on ebay) Quote Link to comment Share on other sites More sharing options...
Daan Posted January 10, 2012 Share Posted January 10, 2012 The good thing about a turbo is that it is free power your using were the supercharger robs you of power to turn the wheels. Also, on a diesel, you can cram as much air in as you like, the more the better. On a petrol though, feeding more air means also injecting more fuel, or it will run lean and not run properly. Also on a diesel, low down you already have loads of torque, so you only need it more at the top end. So all this makes the supercharger more suited to petrol. The ebay thing is interesting, but I wouldnt do it that way. The path from the supercharger is so long that you still have a lag to cope with. Also, at higher revs, I reckon you are starving the turbo of air, as the charger only displaces air and that wont be enough for the turbo. The problem is that they are in series, if they were parallel, it would be better. The merc (clk or slk I think) had them parallel, with the supercharger on an elektro magnetic clutch. It then only works on low rpm, untill the turbo kicks in. If you were to set it up like this on a tdi, that might work well. Daan Quote Link to comment Share on other sites More sharing options...
ian_s Posted January 13, 2012 Share Posted January 13, 2012 i can see how having the two in series would be good, eliminating the lag at low revs, but as Daan says you could end up robbing the TC of air at high revs/high throttle openings. the SC would have to be geared to provide at least a little bit of boost at the top end. the boost provided by the turbo would then still be controlled by the wastegate. i assume that the inlet pressure achieved by a standard set up at max throttle/rpm is not limited by the TC itself, if so then as soon as the turbo is boosting enough, the SC is redundant and is just dead weight, eating up precious horses having them in parallel would would give you the best of both, but if you had the clutch on the SC then getting it to cut out at the right time could be interesting, and crucial. i think you'd have to have a pressure sensor on both the outlet of the TC and the SC, and when the TC pressure is higher than the SC, disengage the clutch. if the clutch disengaged too early you'd end up with a huge flat spot in the middle as you lose all boost. you'd also need some kind of one way valve on both, to stop the boost created by one disappearing out through the other. either way, it seems to be a lot of work for not really much benefit, and will also probably shorten the life of the engine considerably! Quote Link to comment Share on other sites More sharing options...
redneck Posted January 13, 2012 Share Posted January 13, 2012 The good thing about a turbo is that it is free power your using were the supercharger robs you of power to turn the wheels. Daan Turbos also rob you of power, by adding a restriction in the exhaust. There is no such thing as a free lunch, they're both pretty close in power drain. But Turbos are much cheaper to produce and fit, hence the manufacturers preference for them. Personally I cant see the point in sticking a supercharger on TDi just tweak the turbo, intercooler etc. If you want loads of "usable" power, no point having a high power, narrow power band engine in an offroad vehicle, then stick a bigger engine in. Some Detroit diesels Run twin turbos and a supercharger but they were 2 stroke engines, the sound is amazing. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted January 13, 2012 Share Posted January 13, 2012 Get any of it wrong and the super charger will most likely stall the compressor on tne turbo.. VNT every time. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted January 13, 2012 Share Posted January 13, 2012 While nosing round at the London boat show last weekend I had a peek at some huuuge Volvo Penta marine diesels. I am sure one had both a belt driven supercharger on the front of the engine, and a whopping great turbo too Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted January 13, 2012 Share Posted January 13, 2012 While nosing round at the London boat show last weekend I had a peek at some huuuge Volvo Penta marine diesels. I am sure one had both a belt driven supercharger on the front of the engine, and a whopping great turbo too You were looking at diesels? welcome to the dark side Quote Link to comment Share on other sites More sharing options...
mickeyw Posted January 13, 2012 Share Posted January 13, 2012 Barry, it appears big boats and petrol don't go together, unlike Landrovers Quote Link to comment Share on other sites More sharing options...
Ed Poore Posted January 14, 2012 Share Posted January 14, 2012 Something that being pondered amongst some friends who are into the amateur rally scene is to build a kind of KERS / regenerative braking system. Except rather than store the energy in batteries you store compressed air into a dive cylinder. When you want a boost you can then dump that air through the intake. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted January 15, 2012 Share Posted January 15, 2012 Me too, but I can't decide if the jet of air should go into the exhaust side of the turbo to keep the shaft speed spooled up? But a venturi with compressed air up the middle on the inlet side would inject a lot of air... This sort of stuff could have been done 50 years ago, but the right sort of thoughts have to come together, and Kerrs has definately done that. A lot of folks are having a ponder on waste brake energy Quote Link to comment Share on other sites More sharing options...
Daan Posted January 15, 2012 Share Posted January 15, 2012 Something that being pondered amongst some friends who are into the amateur rally scene is to build a kind of KERS / regenerative braking system. Except rather than store the energy in batteries you store compressed air into a dive cylinder. When you want a boost you can then dump that air through the intake. This has been done in WRC, were the excess presure of the turbo coming from the dumpvalve were stored in tanks in the bumpers, to be used under acceleration. It worked, then got banned by the FIA. Daan Quote Link to comment Share on other sites More sharing options...
Daan Posted January 15, 2012 Share Posted January 15, 2012 Turbos also rob you of power, by adding a restriction in the exhaust. There is no such thing as a free lunch, they're both pretty close in power drain. I find that very hard to believe, the powerloss of the restriction you create in the exhaust is nothing compared to the powerloss of driving it direct. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 15, 2012 Share Posted January 15, 2012 I find that very hard to believe, the powerloss of the restriction you create in the exhaust is nothing compared to the powerloss of driving it direct. I remember someone posting about having two turbo charged identical engines, producing same power output. then ran them both up, but with the exhaust of one feeding the other turbo, so you can work out the losses, if that makes sense? Result was the engine with no turbo on it's exhaust (only on it's inlet) was producing 40BHP more than the other one, which IIRC was about a third more than the single turbo'd bike engine. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 15, 2012 Share Posted January 15, 2012 It's also worth noting that VW do a supercharged and turbocharged 1.4l petrol engine in a Polo/Golf, which is pretty interesting In fact here it is:http://www.gizmag.com/combination-supercharger-and-turbocharger-for-vw-golf-gt/4595/ Quote Link to comment Share on other sites More sharing options...
Daan Posted January 15, 2012 Share Posted January 15, 2012 I remember someone posting about having two turbo charged identical engines, producing same power output. then ran them both up, but with the exhaust of one feeding the other turbo, so you can work out the losses, if that makes sense? Result was the engine with no turbo on it's exhaust (only on it's inlet) was producing 40BHP more than the other one, which IIRC was about a third more than the single turbo'd bike engine. But on a petrol engine this effect is more of a problem than on a diesel, due to changes in combustion due to backpressure. Also, there is another effect with a turbo: the outlet stroke may be harder due to backpressure, but the intake stroke is easier, because there is no longer a vacuum, but a pressure. So this test would not take that into account. But as said, on a diesel it is very lucrative, so much so that I am not aware of n/a diesels available anymore, but most petrol engines still are n/a. Daan Quote Link to comment Share on other sites More sharing options...
redneck Posted January 15, 2012 Share Posted January 15, 2012 I find that very hard to believe, the powerloss of the restriction you create in the exhaust is nothing compared to the powerloss of driving it direct. A turbo is a compressor, it requires power to drive it, not as much as a supercharger, but it still takes power. Like I said, no free lunch. Quote Link to comment Share on other sites More sharing options...
elbekko Posted January 15, 2012 Share Posted January 15, 2012 I recently read about this thing: http://www.scuderigroup.com/the-scuderi-air-hybrid-system/ Which seems to have the capability to charge an use an air tank. I'm not sure about the rest of the engine design though Quote Link to comment Share on other sites More sharing options...
Mr Ian Posted January 16, 2012 Share Posted January 16, 2012 Some time ago I was at ZF UK and saw an early design of a mechanical driven turbo, basically the turbo was 'driven' by the engine at lower speeds via a gearbox and importantly a sprag type freewheel, once the turbo came up to speed it just overan the manual drive and continued as a normal turbo. Have searched but cannot find any ref to this design so assume it was a failure, ho hum you can't winn them all. ian Ashcroft Quote Link to comment Share on other sites More sharing options...
zardos Posted January 16, 2012 Share Posted January 16, 2012 But as said, on a diesel it is very lucrative, so much so that I am not aware of n/a diesels available anymore, but most petrol engines still are n/a. Daan That is probably due to the lower power/torque a n/a diesel would give compared to the same size petrol, bolting a turbo charger on is an easy way to level the performance between petrol and diesel. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted January 17, 2012 Share Posted January 17, 2012 You need a turbo on a diesel car these days to sell it. No one would tolerate a slow car now And Diesels are more expensive, so it lends itself to additions like turbo charging. If your paying more, why not pay more still, for the full monty? But petrol engines are cheap, and I recon its cheaper to increase the size slightly that fit a complex high speed compressor. p.s. I hate guttless diesel turbo cars ! Energy; It takes the same amount of energy to compress air to 15psi in a given engine what ever the pump. The amount of energy going into the pump changes for that 15psi due to its efficiency losses in friction. It's just that one is shaft and the other is turbine drive. The turbo makes good use of the waste exhaust pressure, but Ilmoor have a double expansion engine that could be the next big thing? http://www.ilmor.co.uk/concept_5-stroke_2.php Just to really mess with your minds, an Intercooler or charge cooler might remove 20kW of heat from compressed induction air. That 20 kW is re-obsorbed by the exhaust gas as it expands in the exhaust pipe I only found that out yesterday looking at CAT data sheets. It's obvious, but I hadn't made the conection Quote Link to comment Share on other sites More sharing options...
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