Rate my flatplane V8!

[Jakgoe]

Hey,

Sorry I couldn't get around to this sooner, I see the other guys have done a nice job helping you. I still, however, have a huge suggestion that everyone else just completely forgot to make. Raise the RPM limit! I mean, seriously, the power curves you guys are putting out are fine and all, but man, would the power be more useable if you just raised the limiter by 500-1000 RPM.

Also, Strop, take a moment to consider that you lost 50 ft-lb when you downsized the engine. Not so insignificant. Sometimes, if not most of the time, it is absolutely acceptable to make an engine that is bigger than what you really need for the power goals and such. Larger engines can be more reliable, have better power curves, MUCH more torque, and be more economical. Smaller does not always mean better. A lot of people, companies (I'm looking at you, Mercedes AMG), can get caught up in the idea of downsizing, but it is just not true.

I'll give a shot a tuning the engine sometime later today.

Thanks,

Jack

[strop]

Er, Jack, we already covered the whole rev limiter thing: if you look at the figures, I'm sure you will notice that the redlines have been increased significantly in subsequent examples. In addition, I'm sure you already realise that it gets progressively more difficult to maintain a reliability above 70, 75 etc. if you push it up too high, which of course can be countered by reducing stroke and upping block and valvetrain quality (the quality also affects the peak of power: higher quality low end, later peaks).

Also, as for the torque, I'm not convinced (and this is something also covered in the ?stickied thread about torque vs hp), that torque alone is significant, which is why I suggested swapping the engine file (only I messed up the attachment) to see whether a higher revving but less torquey or more grunty but lower revving engine was better suited to the car. How much mass and how much traction there is would be factors. While you're definitely right in that larger engines (with shorter strokes) can be more reliable and their power curves are easier to manage (that crap torque curve in mine is a side effect of the smaller size, after all), I don't know exactly what kind of car the OP is making here, so it's not all that easy to rightsize.

But, of course, of everybody in the forum I would say you by far are the most familiar with the game mechanics, so I have no doubt there will be something for everybody to learn from your example!

[Jakgoe]

Here's assuming you wanted 570ish horsepower. If you want more, this engine can easily provide that. But for now, this this has large improvements in economy and torque, and a massively improved power curve. To boot, it is also more reliable. This is based off Strop's engine, so give him credit for it!

Rightsizing! Woo!

5.1L FP 40V DOHCRev1.lua

(51.32 KiB) Downloaded 167 times

[Corvette6317]

Tunerguy21 specially said he DIDN'T want a performance intake, your engine BARELY has more reliability than my second engine (my first has more than yours) and strop's engine, not to mention how Tunerguy21 also specially said he wanted really high power per liter! Sorry if this seems harsh but you failed Jakgoe, then again come to think of it Tunerguy21 only ever asked for constructive criticism so unless if you were trying to one up us then you wasted your time in the first place.

Keep in mind that I have another version with a performance intake already fitted, so that possible improvement has already been covered (that one is for a different version of the car, though).

I would normally just go with a larger displacement engine, but I'm a strong believer in power-per-liter over just outright grunt, so I tried to get a higher revving, lower-displacement engine to make similar power to larger engines like those of the Gallardo/Huracan (and for the Huracan I'm already down on power, so I'm glad my car is light).

[Jakgoe]

Hey, let's address this point by point.

First off, the performance intake. Perhaps he wants it, perhaps he doesn't. The .lua file is posted, he can change it to standard if he wishes. You used one, I used one, and Strop (who I need to give credit for the basis of my own engine to), used one. That, my friend, is called being hypocritical.

Reliability. I said it was more reliable. Not much more reliable, just more reliable. Nothing to see here.

As for power-per-litre, did you not read what I said? This engine has a lot more to give, but I purposely kept it to 570ish hp. It has over 110hp per liter, which, if I may say so, is very high for a naturally aspirated engine.

So unless if you were trying to one up us then you wasted your time in the first place.

Please explain how me building an engine is any different from you guys doing it.

Cheers,

Jack

[Irkie500]

Any particular reason why you set the rev limiter to 8800 when the power peaks at 7600? A rev limit of 8000 would be plenty to stay in the power band and would give a couple extra points the reliability for sure. 8800 to me seems really excessive because when you shift you would be right at the peak of the power band and move right past it, instead of shifting slightly before, riding the power slightly past the peak and shifting again.

[Corvette6317]

Hey, let's address this point by point.

First off, the performance intake. Perhaps he wants it, perhaps he doesn't. The .lua file is posted, he can change it to standard if he wishes. You used one, I used one, and Strop (who I need to give credit for the basis of my own engine to), used one. That, my friend, is called being hypocritical.

Reliability. I said it was more reliable. Not much more reliable, just more reliable. Nothing to see here.

As for power-per-litre, did you not read what I said? This engine has a lot more to give, but I purposely kept it to 570ish hp. It has over 110hp per liter, which, if I may say so, is very high for a naturally aspirated engine.

So unless if you were trying to one up us then you wasted your time in the first place.

Please explain how me building an engine is any different from you guys doing it.

Cheers,

Jack

Did Tunerguy21 use a performance intake on either of his engines? No! Did I use a performance intake on my first engine? No again! Strop was the one who started using performance intakes, I felt he was trying to outdo me so I uploaded the second engine just to outdo him and nothing else. So no hypocrisy on my end, just laziness or poor reading skills on yours.

Does your engine have more reliability than either of Tunerguy21's engines? Heck no! His has more than 10 reliability over yours! Does your engine have more reliability than my FIRST engine? Nope, and just to prove how you're still just as lazy or bad at reading as before you totally ignore how I said my first engine has more reliability than yours in the post you just responded to.

And yes I did read what you said, sadly I can't say the same for you reading what me and Tunerguy21 said. Your engine may have more to give but so what? This thread was about Tunerguy21 wanting constructive criticism, not for others to post engines with room for improvement.

I can't speak for strop but I was just basically wanting to show off, so unless if that's what you were trying to do then yes you doing it is different to me doing it.

You're a freaking idiot dude, and unless if you're going to apologize then I'm just going to ignore you from now on.

[nialloftara]

Any particular reason why you set the rev limiter to 8800 when the power peaks at 7600? A rev limit of 8000 would be plenty to stay in the power band and would give a couple extra points the reliability for sure. 8800 to me seems really excessive because when you shift you would be right at the peak of the power band and move right past it, instead of shifting slightly before, riding the power slightly past the peak and shifting again.

It depends on gearing, as this is just the engine file we don't know if its getting a wide ratio high speed box which could make use of the extra rpms or a close ratio track box which might not need them. Better to have them first and retune after its in the car.

[nialloftara]

*rant*

Whoa dude! Let's take a second and calm down, this thread was about giving ideas and constructive remarks on tunerguy's engine, every one has a different style of building and different ideas on what's best. How about we just give our ideas and let tunerguy take what works best for him from the results. Same for strop and jack this should be for helping not showing off.

[Tunerguy21]

Alright, first I apologize for not getting on sooner, but I woke up kind of late and had some running around to do before I take a trip down to Florida. Now, Corvette is right about the fact that I want a lower displacement. I'd like to keep it at the current 4.8 liters, but I will try the other two engines regardless for the sake of comparison and I'll edit this or post again with the results. What I'm going to do is list the parts my engine uses, and if anyone is willing to tinker with my exact design and let me know how to improve it, please do.
Bottom End: Quality +2
AlSi Block
101mm Bore
75mm Stroke
Billet Crank
I-Beam Steel Rods
Lightweight Forged Pistons
Top End: Quality +8
DOHC 40v
AlSi Heads
12.7:1 Compression
Cam Profile: 65
VVT: All Cams
No VVL (obviously)
Fuel System: Quality +8
Direct Injection
ITBs
Standard Intake
Premium Unleaded
11.8:1 AFR
Ignition Timing: 94
RPM Limit: 8400
Exhaust: Quality +3
Long Tubular Headers
Dual Exhaust (no bypass)
2.75 Diameter Piping
High-Flow Cat
Muffler 1: Straight Through
Muffler 2: Reverse Flow

Once I try the other two engines, I'll post up comparisons. And please keep the fighting out of this thread. We're all friends here (I would hope).

EDIT: If anyone could explain why all the power/torque curves were different to mine, that would be greatly appreciated. Mine seems to be much smoother of a climb while others have an abrupt increase in the upper revs.

[Irkie500]

You could probably drop the crank down to a forged unit or even cast unit to save some $ and man hours. The cast unit seems to hold really well against almost all power except the most extreme, although im not entirely sure how it will fair with the high RPMs.

[Corvette6317]

Right off the bat your AFR is too high, for a non-forced induction engine with direct injection you should never exceed 12.0:1, whether you lower timing or compression to make that happen is up to you but either should see more power, torque and efficiency right there.

This is possibly the last you'll hear of me since this account got a board warning and the owner may decide to not let me post anymore.

[nialloftara]

Direct injection can go to 11.8:1 without running rich. I'm on my boat till tomorrow night but I'll try and play around with your engine then.

[Tunerguy21]

Direct injection can go to 11.8:1 without running rich. I'm on my boat till tomorrow night but I'll try and play around with your engine then.

Alright. I look forward to seeing what you can make of it. Unfortunately, while I'm in Florida I won't be able to get on Automation, but I'll try to do what I can while I'm still here. As promised, I'm including comparisons of strop's, Jakgoe's, and my engines.

[Tunerguy21]

Strop's engine.