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Forced induction engines are always going to be easier to get power out of. Pretty simple really, when building an NA motor, the whole aim is to try and get more air into it... The more air you can get in there the more horsepower you will make, it is very hard beyond a certain point to get any more air in at atmospheric pressure. Add pressure and all of a sudden perfect inlet ports etc don't really matter as much. Eg, my 1.6l corolla rally car makes 130kw atw, massive number for an engine like that, and equivalent to 210atw of a 2.6l....

they've had variable vane turbos & common rail injection on turbo diesel patrols & navarras for awhile now

manufacturers invariably go for the cheapest or cost effective option available at the time, makes sense that technology becomes more accessible ie cheaper over time

same reason early r series skylines had ceramic wheel turbos from factory rather than steel (N1 turbos excepted)

it's economics

they can totally make a household lightbulb that could last a lifetime, we haz the technology, but it wouldn't be very profitable for the company manufacturing these lightbulbs

  • 2 weeks later...

ok a few points to make here,

1: if f1 technology was used so much in road cars then we'd be seeing plenty of cars reving to well over 10,000rpm

2: turbo cars aren't that much cheaper to get power out of, people just tend to forget about the expense of getting power out of a turbo engine. the initial gains from a turbo car can be cheap (wind the boost up a bit), but after that the dollars start to climb very quickly. work out the price of a new turbo, ecu, injectors, etc. sure it will gain you more power than a natro, but it has also cost you a lot more.

3: if turbos were more common on cars then skylines would be less desirable. why would people spend 10 to 15k on a skyline when for half the money you could buy a turbo commodore or falcon that would most likely be putting out more power and be faster?

4: there will always be NA cars since they are always cheaper.

5: bigger engines with turbos overcome the lag. xr6 turbo is a perfect example. peak torque starts at 1500rpm, and the pull like a train throughout the rev range.

they've had variable vane turbos & common rail injection on turbo diesel patrols & navarras for awhile now

The variable vane turbo on the ZD30 is a bad example with Nissan's poor electronic control causing over boost.

Unless the operator is watching his instruments, this fragile engine doesn't last long.

Garrett and Holsett are having sticky vane problems in diesel applications, unlike the Cat C-15 which runs a conventional wastegate controlling the series mounted turbos.

Looks complicated but works.

Once they go, Cummins ISX operators are ditching the variable vane turbo in favour of much cheaper and reliable internal wastegate versions.

Clearly a lot more R&D required by turbo manufacturers.

ok a few points to make here,

1: if f1 technology was used so much in road cars then we'd be seeing plenty of cars reving to well over 10,000rpm

2: turbo cars aren't that much cheaper to get power out of, people just tend to forget about the expense of getting power out of a turbo engine. the initial gains from a turbo car can be cheap (wind the boost up a bit), but after that the dollars start to climb very quickly. work out the price of a new turbo, ecu, injectors, etc. sure it will gain you more power than a natro, but it has also cost you a lot more.

3: if turbos were more common on cars then skylines would be less desirable. why would people spend 10 to 15k on a skyline when for half the money you could buy a turbo commodore or falcon that would most likely be putting out more power and be faster?

4: there will always be NA cars since they are always cheaper.

5: bigger engines with turbos overcome the lag. xr6 turbo is a perfect example. peak torque starts at 1500rpm, and the pull like a train throughout the rev range.

1-not exactly. but what it has done is develop technology that enables engines to rev higher, and more reliably.

2- yes and no. But it sounds like you are coming from the perspective of increasing power aftermarket.

Building a car in the manufacturing process to develop 'x' power (x being quite a high figure- lets say in excess of 500-600hp) then building a turbo motor to do it would arguably be cheaper. Again, still something very debatable. But i spose a good point to consider is how many road going manufactured cars in excess of 500hp are turbo'd n how many are NA..

3- true

4- true

5-also true. Cmon, we have been dying for larger cc skylines for ages. Hence RB30/25 :)

Edited by jjman

I wonder what engines will be like in a few decades? I mean a 2.0L mx5 produces the same power as a 4.7L 60s mustang nowadays, there are probably smaller capacity NA engines which do as well, I guess the next step would be in using efficiency to close the torque gap.

(Though the life of petrol engines is not getting any longer, it'll be something else that replaces it. Hopefully something like methanol so that some of the characteristics we love about engines will still be there, rather than just battery or fuel cell powered whirring.)

Anyway, what I was getting at at first was that if engines become more efficient (only a small percentage of the available chemical energy is actually converted into power, ~10%) 500cc engines could be putting out the power of big v8's, but still the more cc's the easier it will be to produce power.

And if manufacturers only cared about maximum speed they would ALL be forced induction.

However, when a manufacturer also cares about throttle response and exhaust note they are hesitant to go turbo. A lot of Lambo's and Ferrari's are sold on sound, not whether they go 380 or 390kph.

I think when you've got 300+ kw/tonne then other things become more important than extra power.

Currently the focus is on direct injection with smaller turbos and high compression (but lower revs). Most of the direct injection Euro engines are making great torque and throttle response but don't rev high so they reduce consumption.

I would love to see a direct injection, medium sized single turbo straight 6 with decent revs in a light-weight chassis (the next Z-car)?

ie. If Nissan remade a sports direct injection straight 6 of say 3.0L capacity.

All alloy with 10:1 compression,

10psi, twin scroll T3 (based around a GT2835 or some such)

Direct injection

Decent intercooler and exhaust with half-decent cams to make peak power at 6500rpm.

realistic figures would be something like:

470Nm from 2500 to 5000rpm

290kw at 6500rpm

Aftermarket would go b-a-n-a-n-a-s.

Alternatively they could go S16 with even lower weight ~1200kg flat, new direct injection 2.0L with decent revs and have:

350Nm & 215Kw.

Now that would be hot cake material.

I like the way you think Simpletool.

sounds like that something that can be gotten wrong tho- hence the multitude of comments about the MX5 turbo a few years back that "it feels like the turbo isnt hooked up"

its a shame when they go too soft... Iv driven one myself and was thoroughly dissapointed. With a turbo you really want some sort of power curve/top end push to let you know its there. Certainly didnt have that...

I wonder what engines will be like in a few decades? I mean a 2.0L mx5 produces the same power as a 4.7L 60s mustang nowadays, there are probably smaller capacity NA engines which do as well, I guess the next step would be in using efficiency to close the torque gap.

(Though the life of petrol engines is not getting any longer, it'll be something else that replaces it. Hopefully something like methanol so that some of the characteristics we love about engines will still be there, rather than just battery or fuel cell powered whirring.)

Anyway, what I was getting at at first was that if engines become more efficient (only a small percentage of the available chemical energy is actually converted into power, ~10%) 500cc engines could be putting out the power of big v8's, but still the more cc's the easier it will be to produce power.

i'd guess that they will be drastically different and not really comparable (talking decades - plural, so at least 20 years). with focus now being on renewable fuels, etc.

The new toyota Ft86 is supposed to have direct injection on a 2L engine. I could see the aftermarket having some fun with that. Of course you'd have to turbo it first, which i imagine could be a right royal pain in the arse.

Edited by sneakey pete

The only problem with direct injection and the aftermarket would be......well think about what it would cost for a set of 6 1000cc injectors for a direct injection motor.

ECU's that could run said direct injection.

Notice the Track oriantated Porsche 911's (GT2 and GT3) still run conventional injectors, so that aftermarket ECU's can run the things.

Sure technology will catch up, but at what price, and with a somewhat limited use atm.

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