Touring Car engine needed!

[quote=“oldgreg”]A good touring car engine is one that gets your touring car around the race track faster than the other guy without breaking any rules. And so, in that spirit, here’s the nastiest fire-breather I could put together within the bounds of the rules.

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I can’t even imagine how many vents would be needed for this engine…

If the engine has 30000+ km mtbf with cooling at 450 kj/s does that count too? :laughing: Because that’s really low for a turbo engine

Thing is, it’s a racing engine, and over the course of the season it will not race even a fraction of that.
That’s why mtbf is not higher. As for cooling, it turned out to be a good natural limiter to the hp. It should be a decent challenge for most.

Okay I’ll give this a shot, given the cooling requirement of <450.0kj/s. I’m sending in a high tech race-bred engine, designed for as much power as the cooling allows, with very high revs and lower peak torque (so you don’t need an insanely heavy transmission to cope), but of course, a responsiveness that will be difficult to match! This is what I believe a good racing engine does.

[quote=“RoninGT21”]Thing is, it’s a racing engine, and over the course of the season it will not race even a fraction of that.
That’s why mtbf is not higher. As for cooling, it turned out to be a good natural limiter to the hp. It should be a decent challenge for most.[/quote]

Well, I think you misunderstood mtbf like most people. MTBF assumes average road use, not being revved again and again to max rpm in race conditions at full power. The engine would last only a fraction compared to when it would be driven as a daily driver. Remember that Automation is mainly simulated for road cars. Especially when parts are stressed they break way more easily in racing. 30000 km mtbf would be like 300 km in racing, on average, meaning it could break sooner or later. A daily life example would be our feet: do your normal walking and daily activities and there’s no problem, but if you go on a 10-20 km walk you can get blisters.

I’m not really happy with the cooling limit, but I’ll try anyways (mainly due to the fact that I just finished a 475 bhp engine with just 3.2% tameness penalty that still has 40000 mtbf with 450 kjs cooling) Time to make a ridiculously economical race engine with some great tame torque.

I agree that Dragawn’s interpretation of MTBF and how it should be used here would make for a superior brief, but would also argue that it would be slightly more impractical (but only slightly, insofar as testing the engine in a frame with 450kj/s of ventilation is impractical). Also, I do think that the spirit of touring cars is to have engines with a relatively narrow spec when it comes to output, so that’s something I’m willing to swallow.

That said, reliability is something I didn’t mention in my initial description of a good race engine but this is a good point (as a certain currently running endurance race goes to show), so I’d encourage MTBF to be a strong criteria for judging. The minimum requirement may be just 30k, but in reality most of the engines considered should have considerably more than that.

hmm, limited cooling sure is a challenge, since it isn’t simply a max horsepower limit .

I already have a high horsepower prototype ready with a tameness boost, but due to it having near 30% economy the responsiveness is poor, although it’d make a great 21st century green racing engine. Second prototype is a more torque-ish variant with 21% economy and a lot more responsiveness, but less tame aswell (so far).
Both have an insane 80000 km MTBF though :laughing:

Dragawn, I’m curious, how exactly do you go about measuring “tameness” of the engine?

The engine I started with had close to 35% economy, but unfortunately the responsiveness was also about 35! On the other extreme, I pushed a responsiveness of about 85 out of the same block… but the economy is now closer to 18% :laughing:

85 responsiveness, well damn that’s some aggressive ignition timing :laughing:

I suppose you have noticed the engine value in the tameness results. I always tune my engine whilst it sits in an existing model with sufficient cooling, since how tame the engine is can take odd turns. So far with my experimenting it pointed out it’s how “predictable” the engine is. A nice steady powergain or drop is easier to use than one with sudden drops, changes, etc. But it’s more complicated than that it seems. I’ve experimented with VVT mixing with normal to get a near perfectly flat torque, but the tameness responded (very) poorly to that, probably due to the cam profile shift or something.

I probably gave out way too much info than I should in order to win this, but here you go.

The penny just dropped for me :astonished:

Suddenly all your talk about tameness penalty makes sense. It turns out that my best touge-conquering turbo engines had tameness penalties in the realm of 4% (something I completely ignored during the Haruna battles)… whereas an engine even twice as powerful, but also twice as responsive, made the car insanely hard to drive with tameness penalties of up to 70%!!!

I suspect however that this stat is more relevant for windier tracks, and the correlation is not necessarily direct as there are many other factors in play, but I’m getting a much better idea of how it is relevant. I’ll have to reconsider whether I should or shouldn’t revise my engine for this, because it may turn out that my engine is too responsive for the task. Or I could leave it at that for the consideration of the OP, which would be more sportsmanlike.

Don’t worry, as long as the competition is open, you can send in revisions.
Also, I would like to thank you all for sending me your submissions.I haven’t had time to check them all, but I’ll get around to it today.

[quote=“strop”]The penny just dropped for me :astonished:

Suddenly all your talk about tameness penalty makes sense. It turns out that my best touge-conquering turbo engines had tameness penalties in the realm of 4% (something I completely ignored during the Haruna battles)… whereas an engine even twice as powerful, but also twice as responsive, made the car insanely hard to drive with tameness penalties of up to 70%!!!

I suspect however that this stat is more relevant for windier tracks, and the correlation is not necessarily direct as there are many other factors in play, but I’m getting a much better idea of how it is relevant.[/quote]

If you look at the .lua file for Haruna, you’ll notice that the “sportiness” values are often quite high, implying crappy pavement and not particularly good traction. High road “sportiness” penalizes untame cars, so it makes perfect sense that your tamest engines were the fastest down the mountain. Now, if you were to edit the track and set the “sportiness” of every section of the track to 0 I think you’d find that tameness no longer made any difference to laptimes. But you’re also right that it is more relevant for twisty tracks, or at least for twisty tracks with non-zero “sportiness”. A 3 mile long straight with sportiness=5 road surface probably won’t have too much effect on an untame car once you’re doing 100+, but through turns and especially when accelerating out of a tight turn onto a straight an untame engine will definitely cost time.

But anyway, Dragawn and Strop, thanks for talking about this. I have a sneaking suspicion that it is going to come very much in handy when I post my second test track. hinthint* :smiling_imp:

I decided to give this a go.

Partially due to some comments suggested in my own engine thread, partially due to me having been trying to work within constraints and compromises in any event, decided to put together this OHV motor.

I put a self imposed man hour limit of 100, and tried to more see how far I can go with the actual MTBF along with a somewhat reasonable fuel economy. This came an obvious cost of engine responsiveness. I could go further with economy and engine response, but a kick in the shins has been keeping limits on cooling.

Then again you learn something new every day and you try to figure out things regardless. I’m sticking with an OHV setup for the time being because I’d have to sit down some more hours to figure out an OHC setup (be it Direct acting, single or dual) properly in regards to working with a turbo AND managing heat.

If heat wasn’t a problem, I could easily put a reasonable 300bhp motor to these specs otherwise with less than 100 man hours…not that I’m bragging or anything.

If this was N/A, I could actually put together a motor for the power, although honestly I don’t know if I could meet the temperature requirements. I’d try now but my computer is crap and I might try later.

That said, here’s my first proposal, but not my ‘final’ one.


The first is again, an attempt at not just making the power, but also torque. However I’ve been trying to properly set up the turbo so it can spin to full speed earlier in the rev range.

But again, a constant problem has been the heat. If that was not an issue, I could put better optimization with fuel economy, power and response.

But then again, I’m sure in the eyes of others…there’s a billion things I could have done better. We’ll see.

I think it’s a fine engine! Here is mine. I absolutely don’t expect to win anything with this, but it’s somewhat efficient, decent enough torque curve, and middle-of-the-road responsiveness. I certainly thing it could hold it’s own! :slight_smile:

I’m a little unsure how to submit. Is it just this photo, a PM, submit engine file?

Thanks for confirming all that oldgreg. I guess the question is now what kind of roads to expect in a touring car championship…

@oldgreg I made the sportiness value like that partially due to the “fear factor” aswell. It’s a steep downhill with no run-off sections if you screw up, only some barriers, overshooting a corner can mean a car wreck and possibly death.

As for touring…I’d say near perfect roads, but tame/sporty ratio seems to always have some effect.

Well, that will be all up to moders, as in one of the latest developer videos I found out that racetracks will need to be redone.

Pushrod power MK2! now lighter, more powerful, and slightly more tame. It’s hand assembled by a skilled team of 25 engineers at a rate of one every working week.


Wow! I can’t believe I felt guilty for having 141 man hours! hahahaha

Wait until you see what I did… Would be pretty easy to scale it back I guess but since the brief said do whatever… Guess the engine does need to be slightly easier to produce I guess!