Jump to content
SAU Community

Recommended Posts

  • Replies 55
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Hi,  Just joined the forum so I could share my "fix" of this problem. Might be of use to someone. Had the same hunting at idle issue on my V36 with VQ35HR engine after swapping the engine because the original one got overheated.  While changing the engine I made the mistake of cleaning the throttle bodies and tried all the tricks i could find to do a throttle relearn with no luck. Gave in and took it to a shop and they couldn't sort it. Then took it to my local Nissan dealership and they couldn't get it to idle properly. They said I'd need to replace the throttle bodies and the ecu probably costing more than the car is worth. So I had the idea of replacing the carbon I cleaned out with a thin layer of super glue and it's back to normal idle now. Bit rough but saved the car from the wreckers 🤣
    • After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
    • For race cars, this is one part where I find having the roll cage bar having gone through a hole in the floor better than the build it up on a ledge inside... The Merc I help on, the main hoop ends are marked on the car, and the jack is marked... Jack goes under a few inches and lifts one whole side of the car up... Removes that fight for long slim jacks for race car duties!   My biggest issue for the daily drivers I work on, is my jacks don't go high enough. The jacks start out on a few blocks, jack it up, then start a second jack under it on more blocks, and then I can get an axle stand under it. My axle stands are presently in use, and are nearly fully extended. The car is sitting with barely more than a cm of clearance to get the wheel off the studs! Sarah's Kluger is the same, as it has an ungodly amount of droop available in the suspension and a distinct lack of good jacking points!
    • Happy? Yep, my to do list is getting shorter and shorter. Either this light approaching is the end of the tunnel, or I'm about to be hit by a train... Ha ha ha   Also, Duncan isn't that far out of town that you need to make a multi day drive out of it. 😛
×
×
  • Create New...