nicksmelly Posted February 4, 2011 Share Posted February 4, 2011 Not sure if this guy made a genuine mistake, or he actually thinks a dirty old V8 can produce 390bhp... He says its a 3.9 by JE, but it's on flapper efi, so likely to be a 3.5 producing 390bhp. Ebay linky clicky thing I want it Quote Link to comment Share on other sites More sharing options...
missingsid Posted February 5, 2011 Share Posted February 5, 2011 Personally I would be amazed, The 2nd generation BMW M3 was notable in its day as the only naturally aspirated production car to have over 100BHP per litre. The V8 M5 only produced 400BHP out of 5 litres and the current V8 M3 produces more than 100BHP per litre. As far as I was aware the normally aspirated but tuned Rover V8 was around 200-250BHP for a 3.5 unless very special, so I would not expect too much more from a 3.9. HfH Nige would be good for comment on this I guess. Marc. Quote Link to comment Share on other sites More sharing options...
robhybrid Posted February 5, 2011 Share Posted February 5, 2011 Years ago 100hp per litre was talked about as a magical figure difficult to beat I remember reading vissard? books on tuning engines. Quote Link to comment Share on other sites More sharing options...
Steve Hiatt Posted February 5, 2011 Share Posted February 5, 2011 I noticed the other day that the Ford mini MPV is 2lt and 200hp, just shows how things have come on. I guess £2k might get you over JE's doormat but I think 190hp might be more realistic. Quote Link to comment Share on other sites More sharing options...
Paul Wightman Posted February 5, 2011 Share Posted February 5, 2011 These days 100 bhp/ltr is nothing, my 'toy' is producing 370 bhp out of 2 ltr. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted February 5, 2011 Share Posted February 5, 2011 Since materials moved on to allow substantial turbocharging in petrol engines (above 1000degrees C EGT ) power levels have leapt up. 100bhp per litre would still be impressive from a naturally aspirated engine, there aren't many production N/A engines that beat that figure - though I'd like to check the calibration settings on the dyno sheets for the ebay V8... Quote Link to comment Share on other sites More sharing options...
Phantom Posted February 5, 2011 Share Posted February 5, 2011 My Seadoo ( RXT RS ) is 1.5 litre, producing 260hp and accelerates quicker than a Ferrari – Guess the supercharger helps! Quote Link to comment Share on other sites More sharing options...
nicksmelly Posted February 5, 2011 Author Share Posted February 5, 2011 I'm sure there will be someone who falls for it and fits it to a 2 ton Discovery, tells everyone in the pub about his 390bhp engine and 3 seconds 0-60. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted February 5, 2011 Share Posted February 5, 2011 As for what state the gearbox would be in after having 390bhp put through it... :lol: Quote Link to comment Share on other sites More sharing options...
missingsid Posted February 6, 2011 Share Posted February 6, 2011 These days 100 bhp/ltr is nothing, my 'toy' is producing 370 bhp out of 2 ltr. Errrr Naturally Aspirated. Marc Quote Link to comment Share on other sites More sharing options...
robhybrid Posted February 6, 2011 Share Posted February 6, 2011 out of interest whilst at the autosport show the other week there was a rotrex tts performance supercharger stand that had a Honda type r engine stock hp 175 at the wheels that they uprated to 365 at the wheels.using twin Superchargers. Is the type r 2 litre? Just for £3750 + vat diy fitment, and a small note about highly recommending the use of uprated rods and pistons if being used for competition use. Quote Link to comment Share on other sites More sharing options...
orangebean Posted February 6, 2011 Share Posted February 6, 2011 On manufacturers figs I get the equivalent of 186 hp/l from my normally aspirated Honda NS400R. Nasty smelly polluting 2 stroke horses Quote Link to comment Share on other sites More sharing options...
Paul Wightman Posted February 7, 2011 Share Posted February 7, 2011 Errrr Odviously turbocharged! Why struggle with a naturally aspirated engine when something as simple (relatively speaking) as adding a turbo gives an easy power increase. Marc Quote Link to comment Share on other sites More sharing options...
missingsid Posted February 7, 2011 Share Posted February 7, 2011 I have no issue with it other than the topic is about NA engines. Marc. PS I like the idea of getting high power without a Turbo. Quote Link to comment Share on other sites More sharing options...
will_warne Posted February 8, 2011 Share Posted February 8, 2011 out of interest whilst at the autosport show the other week there was a rotrex tts performance supercharger stand that had a Honda type r engine stock hp 175 at the wheels that they uprated to 365 at the wheels.using twin Superchargers. Is the type r 2 litre? Just for £3750 + vat diy fitment, and a small note about highly recommending the use of uprated rods and pistons if being used for competition use. Rob, it'll last about 2 minutes especially if it is a current generation Civic (which has weaker internals than the earlier version). That said, a K20a (first gen Civic type r engine) can be tuned to about 360 at the crank (so a little over 300 bhp at the wheels) with standard internals using a supercharger, charge cooler and some cams (TODA A3s are good but you'll loose some mid range). Something like this is likely to end up in my Lotus at some point As others have said, 100 bhp/litre is still impressive in an n/a production car and, although easy enough to achieve on small 4 cylinders, it is impressive to get a figure like that out of a larger V8. It certainly isn't impossible BUT it's unlikely. Quote Link to comment Share on other sites More sharing options...
nicks90 Posted February 8, 2011 Share Posted February 8, 2011 As others have said, 100 bhp/litre is still impressive in an n/a production car and, although easy enough to achieve on small 4 cylinders, it is impressive to get a figure like that out of a larger V8. It certainly isn't impossible BUT it's unlikely. so how do they get it out of smaller 4 cylinder 4 strokes - like bike engines - but cant do it with higher displacement engines? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 8, 2011 Share Posted February 8, 2011 With revs! Quote Link to comment Share on other sites More sharing options...
Aragorn Posted February 8, 2011 Share Posted February 8, 2011 Exactly, a bike revs to 15k+! The problem with getting 100hp/litre from an NA car engine is it needs to be very "cammy" to get there, which ruins emissions and makes it idle like a bag of spanners. The advent of variable valve timing means you can have aggressive enough cams to make the power, but at the same time have an engine that idles properly and passes the required emissions standards. Audi and BMW are both getting more or less 100bhp/litre from large V8 motors, but the major issue with bigger engines is that more reciprocating mass means parts need to be made from lighter and more exotic materials so it doesnt self destruct doing 8000rpm. Audi and BMW are both also running modern multivalve heads with VVT etc. The cylinder head on an RV8 simply cant flow those sort of figures, and the bottom end wouldnt stay in one piece! Quote Link to comment Share on other sites More sharing options...
robhybrid Posted February 8, 2011 Share Posted February 8, 2011 large cc usually means bigger pistons and that means more weight being forced to change direction very quickly, a piston goes from stop to full speed twice in one revolution cause at tdc and bdc the piston changes direction, years ago on my hnd engineering course we did simplified calculations on the forces required and the figures were frightening. Quote Link to comment Share on other sites More sharing options...
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