Performance 400cc I4

[Deskjetser]

This is my 5th or so engine, i'm very new to this so please don't murder me if it's no good.

I decided to make a line of extreme performance engines, starting from the bottom is my tiny little 0.4L Inline four, with a huge meaty turbo bolted on.

It makes for a light, powerful and torquey little monster, albeit with a very short lifespan. However, it does suffer from extreme turbo lag. Please tell me whatcha' think!

Converted stats for all nationalities;
Displacement: 393cc - 0.4L - 24cu
Power: 131hp@8300RPM - 96kW
Torque: 122NM@ 7300RPM - 90.1ft-lbs
MTBF: 159km - 98miles
Weight: 51.1kg - 112lbs
Size: 273 x 253 x 284mm - 10.75 x 9.96 x 11.2inches
Economy: 1428g/kWh - 2.34lb/hp-h - 1050g/hp-h


http://i.imgur.com/gwJQaHz.jpg

[oppositelock]

Not too shabby, just a couple observations:

Turbo is seriously too big. Your peak power is at 8300 rpm, but you're not even making full boost until past 10000 rpm. In fact there's no reason to even rev this thing past 9000, since the power just keeps dropping. The 12000 rpm redline is just helping to kill your MTBF.

Octane requirement is only 66.4. You can run way, way, way, way, way more compression.

Here's something I cobbled together as an example. Same power, better reliability, more usable powerband, and just a tiny fraction of the cost. Only downside is it's a little bit heavier.

0.4L 16V DOHC TurboRev0.lua

(89.59 KiB) Downloaded 269 times

[Deskjetser]

Not too shabby, just a couple observations:

Turbo is seriously too big. Your peak power is at 8300 rpm, but you're not even making full boost until past 10000 rpm. In fact there's no reason to even rev this thing past 9000, since the power just keeps dropping. The 12000 rpm redline is just helping to kill your MTBF.

Octane requirement is only 66.4. You can run way, way, way, way, way more compression.

Thanks for the tips, ill try make a revision of this engine today. Although, after a few tweaks I think it will be neigh impossible to achieve the same torque with a more usable power-band.

[Kubboz]

Who cares about torque? Torque is hardly relevant.

[Deskjetser]

Torque is hardly relevant.

How so? Your confusing me

[Kubboz]

It's the power that accelerates the car, not the torque. And it's a shape of the power curve that determines how the car accelerates. Of course, torque CURVE can be useful (to determine the power distribution, as torque and power are closely related), but the absolute value of torque is almost irrelevant as you can change it with the gearing.

You can watch this video for more explanation: http://www.youtube.com/watch?v=vX8wlkSDwSY

[Noxan9]

It's the power that accelerates the car, not the torque. And it's a shape of the power curve that determines how the car accelerates. Of course, torque CURVE can be useful (to determine the power distribution, as torque and power are closely related), but the absolute value of torque is almost irrelevant as you can change it with the gearing.

You can watch this video for more explanation: http://www.youtube.com/watch?v=vX8wlkSDwSY

..... right...... torque is the thing that does the work in an engine..

horsepower gives you speed, torque gives you momentum, and the higher the momentum, the faster you accellerate.

[Deskjetser]

I'm just working on the completely re-thought version of this engine, i'm throwing out the turbo as it just causes problems for my inexperience. Also, i've sneakily increased the displacement from 393cc to 449cc, so even though it's got an extra 0.5L displacement, sneaky badges on the car can get away with saying 0.4L! (Rules of rounding numbers)

Even soo, i've cut down the man hour costs from 1300 to mid 60s and slashed the material costs from $2200 to $360. Unfortunately the power is halved, down from 130hp it's now mid 60hp, although the power band is much more usable.

Another positive note is that it's 10kg/22lbs lighter than its extreme cousin.


I'll be posting this soon.

[Kubboz]

..... right...... torque is the thing that does the work in an engine..

horsepower gives you speed, torque gives you momentum, and the higher the momentum, the faster you accellerate.

Have you watched the video in question?

3 engines with the same power (but different torque and redline) were put into the same car. The acceleration was NOT better in torquey engine. Torque only tells how power is delivered, but it does not accelerate the car directly.

[Deskjetser]

Ok, so I have two engines here, one is a revised one virtually identical to my original except for a slight change in displacement. The other is the engine I wish I had come up with first, while it may be naturally aspirated and thus lacking power compared with the original design, it is actually a viable engine for commercial use.

Please note: The displacement has been increased from 393cc to 449cc, while this is somewhat sneaky i'm still sure it could be marketed as a 0.4L using the rules of rounding numbers. Tell me what you think about this please!

Firstly, here is the revised engine of the original;
It produces more power and torque, is substantially cheaper to produce in both cost and man hours and last but not least; it has an improved life-span too!
It almost completely makes up for the extreme turbo lag... Although i'm sure if the car was light enough, it wouldn't be too much of a problem.




Lastly, here is the new engine, naturally aspirated, cheap to produce and 10kg/22lbs lighter than the original version of the engine above;
While the power output is half that of the original version of the engine above, it has a substantially more usable power-band, is completely affordable and has a very respectable life-span!

[deanwells1234]

Lastly, here is the new engine, naturally aspirated, cheap to produce and 10kg/22lbs lighter than the original version of the engine above;
While the power output is half that of the original version of the engine above, it has a substantially more usable power-band, is completely affordable and has a very respectable life-span!

Not too sure what you would put this engine into, but with a good gearbox and transmission and a very very small lightweight car you could get a decent car out of this. I know the 98 Saturn S series had around 100 HP in their engines so something like that i assume?

[Deskjetser]

Not too sure what you would put this engine into, but with a good gearbox and transmission and a very very small lightweight car you could get a decent car out of this. I know the 98 Saturn S series had around 100 HP in their engines so something like that i assume?

Yeah, i'm sure this little engine would be fine for a little runabout car. A little hatchback platform would make a nice little home for it, just so long as the weight was kept down i'm sure it would be a viable consumer car.

I'm probably going to do some inline 4s with larger displacement next, say 1000cc or so. I'll post again once I start.

[deanwells1234]

I'm probably going to do some inline 4s with larger displacement next, say 1000cc or so. I'll post again once I start.

Ya a majority of cars are between 1L - 2L engines. I myself stick within the 2L - 3L range, Could probably use some smaller engines to go in my cars as well

[oppositelock]

You've done a much better job of optimizing these new engines. Any reason for going from DOHC to SOHC, though? Since it looks like you're trying to wring as much power as possible out of these tiny engines, it seems like an odd choice. Also, if you plan on putting it in a regular production hatchback, you may want to consider mufflers, an air filter, and tuning it for lower octane fuel.

[Deskjetser]

Any reason for going from DOHC to SOHC, though? Since it looks like you're trying to wring as much power as possible out of these tiny engines, it seems like an odd choice. Also, if you plan on putting it in a regular production hatchback, you may want to consider mufflers, an air filter, and tuning it for lower octane fuel.

It seemed a better option for lifespan, it was also cheaper and I didn't want the service costs to be crazy high, so that along with other things was why I went for SOHC.

Also, these engines are just fore runners to the actual things if I were going to put them in cars, they are currently prototypes to help my learning curve.