The Single Engine Lineup Challenge (REVIEWS POSTED)

@abg7 that’s a fairly good summary of my suggestions, although I want to emphasize that nothing I say here is the end-all-be-all. I’m still learning just like anyone else, and what I’ve suggested here is based on my experience building competitive everyday cars.

For valve train type, it’s important to note that DOHC is not always the best choice; the power and efficiency is good but it’s also very expensive. All of the valve train types have their purpose. While I generally avoid OHV/MOHV in modern years since they don’t offer VVL, there’s nothing inherently wrong with using them, and they certainly have their uses when trying to build an engine that is easy to produce or very lightweight. (In real life, OHV is a staple even in modern, high-performance muscle cars, so it makes total sense to use them for a muscle car challenge!)

If you want to send me your cars, I would be happy to do a review for them. Seeing as how you were the only one I didn’t get to review, it would be nice to round this out so I can say I reviewed every car. I for one am interested in seeing the lineup with by far the best efficiency!

@koolkei One thing to keep in mind is that for most of these markets, comfort is valued far more than sportiness. A lot of people tend to ignore engine noise, but it plays a very important role in comfort. Adding noise is easy, but reducing noise is a lot trickier. That’s why I think it’s important to choose quiet engine options, when they aren’t too expensive.

For the mufflers, double baffled is the better choice as long as you don’t choke the exhaust. They really are a lot cheaper and quieter. I’ve found that choking the exhaust doesn’t help efficiency that much, and tends to hurt drivability as well. There are better ways to achieve efficiency.

Keeping the intended market in mind, it makes a lot of sense to trade some power/efficiency for comfort. My retuned engine only gets about 0.3 mpg less fuel economy in the cars, and the reduced noise offsets the loss in smoothness from +0 in bottom end. So it’s almost 20 PU cheaper with next to no loss.

This is also part of the reason for the really bad interiors. Your cars are over budget, and a good interior puts them further over budget. So rather than just leaving the basic interior, you should consider where else you can lower costs so you have money for a good interior.

@rk38 glad to hear that I helped! The next update is arriving in the coming weeks, and I’m going to need some time to get familiar with the new balance tweaks. We’ll see about stage 2 after that. I’m thinking it will be in a different era, and maybe I’ll throw in some additional judging criteria to keep things interesting :wink:

This is true, I also feel like performance intakes are OP when it comes to performance. They don’t do as good a job with noise reduction, however, so you may take a slight hit to comfort, but the muffling system needs revamping anyway so it’s barely relevant.

oh, I see phale’s kind of addressed this already.

Matters mainly if one wants top end power since that’s when the flow is high enough to get restricted. And since you get higher power with higher revving…

No shit! It’s called a performance intake for a reason :stuck_out_tongue:

This is an important point. Top end power is only demanded by the 3 sporty markets. The rest demand low end power, where short cast headers make more sense.

lol okay that was a bit of an English fail on my part :joy:

What I meant was, the way the numbers play out in the game, one would wonder why one hasn’t gone out and immediately replaced their stock box with a K&N or something already. But then again that’s probably due to the altered way in which one assesses cars compared to real world experience. Or is it?

Abg7

Engine
1.6L I4 DOHC-4 VVL
Turbo DI
162hp - 115.5 PI - 73.2 reliability - 31% efficiency
$1381 mat cost - 39.3 PU - 157.37 eng time

I have to say, at first glance, the Harris engine is remarkably well-designed. It’s inexpensive, quiet, and has good efficiency and power. It doesn’t have any of the problems I pointed out with the other engines, aside from the use of a high-flow cat. If you only look at the results in the engine designer, then this is the best engine by far.

I’m really glad that abg7 submitted this engine for review, because it allows me to demonstrate the next level of engine design - designing the engine for the big picture, instead of by itself. This is something that can be difficult to grasp, since you can’t see the big picture effects when tweaking in the engine designer. Take a look at these screenshots to see what I mean.

The original engine.

My version. Note that it is both less powerful and less efficient.

The car with the original engine. The big problem here is the engine’s -10% drivability modifier.

The car with my retuned engine. With some minor changes, I was able to improve the modifier to -6.4%, so drivability goes up significantly. Also notice that the car is now 2.5mpg more efficient, even though the engine efficiency is lower!

I’m not going to say what exactly I did to improve this, because @killrob has stated that the calculations are going to be redone, so my advice will be irrelevant in a few weeks. But the point here should be clear: the big picture is what matters!

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Since your version of my engine develops peak power at redline, I have to ask this question: Could the engine (after your revisions) develop more power with an extended redline, and if so, how much? This would require stronger internals, which would lead to reduced efficiency and increased cost, but I still want to find out.

Peak power comes at 7600RPM and peak performance index comes at 8200RPM. But if you increase the rev limiter, not only does the reliability drop, but the drivability drops as well. So the practice of setting the rev limiter past peak HP RPM actually hurts competitiveness. (I hope you’ve gotten that fixed @Killrob :slight_smile: )

No, we have not fixed that yet. What happens is that a straight line is fitted to the torque curve via a least squares fit. The R^2 value (quality of the fit) is used to modify your drivability as a measure of how predictable the power delivery is. Extending the RPM beyond peak power adds more to the “away from the line” part and decreases R^2. That is a flaw in the calcs we need to fix eventually.

I think a good solution to that would be to only do the fit for common driving RPMs, say 1800-4000RPM or something like that. Because I don’t think anyone would say that torque falling off at 7000RPM is ‘unpredictable’. This would mean that turbo engines with flat torque curves would actually be very good, instead of tanking drivability like they currently do.

True, but if it were that easy I would have done that from the start. What about engines that rev to 3500 RPM? What about engines with an idle of 2000 RPM and a redline of 11000 RPM (which you’d not drive much below 3k RPM)? What about engines with turbos that have peak power at 6k RPM and basically keep said power for 3k RPM? Any solution needs to cover all thinkable extremes so that there are no exploits, otherwise it’s not better than the current solution.

Hmm. Maybe the drivability modifier should take gearing into account then, similar to how economy is calculated. Like, take the RPMs used for the cruising and acceleration tests, and do some sort of fit between them. Not sure if that is feasible.

Thanks for reviewing all the cars (and engines!) @phale, it was very insightful to read your feedback on the submissions. I’ve fallen into the routine of making similar choices each time I try to design an engine (performance intake, tubular exhaust, etc.) and it was helpful to get another perspective.

Fine-tuning to gain fractions of a point here and there took forever - updating my engine in response to your review gained each car 5-10 competitiveness in less than 5 minutes :smile:

I don’t know if you have the answers but I was just wondering why the brake performance is so bad in the game compared with real life? I based the brake setup of the Belinta on similar sized and weight compact vehicles which all use a vented and solid setup and roughly the same diameter (as close as the game would allow) as I did yet in the game that still gave me lots of fade. While I assume the real life models manage to perform adequately for the market. In fact, most vehicles in this class seem to still use solid rear discs. Putting vented discs on the rear adds considerable extra material and production costs compared with solid discs.

That’s a good question, and I don’t know the answer.
Might have to summon the @Killrob again, since I am also interested in knowing how braking is calculated :slight_smile:

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Well, first of all: how do you know the real cars have no brake fade at all?
The fade calcs take into account the top speed if I remember right, so higher top speed = more fade rating.

Considering the rather large effect that fade has on drivability, it seems like it would be a poor choice by real-life manufacturers to not use vented discs. It’s also possible to increase braking performance so solid rear discs don’t fade, but this screws up balance, requiring more pistons up front (which makes trying to save money on the rear brakes pointless).

Speaking of balance, many real-life cars use 4 or more pistons in the rear, which in-game would be terrible for balance. I never need more than 1 or 2 pistons in the rear for all but the most extreme of cars.

But just think, you only really get fade with repeated, heavy use, and how often does that happen in everyday driving IRL?

That’s why I think fade is overrated in game, especialy as far as drivability goes.

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heck. i built a supercar with 1 piston vented rear :stuck_out_tongue:

everyday car are designed to handle more abuse than everyday use isn’t it?

like. everyday, maybe not. maybe not even every year. but when you do take your car to a big mountain. when you’re going downhill, you’re gonna appreciate / feel like you need the bigger brake disc.

but like, vented disc are really only critical on the front. some cheapo cars are still on drums on the rear. even honda fit still has solid dics on the rear. which kind of makes sense. front handles more weight than the rear on braking…