The Highway Patrol Challenge [Reviews]

[Kampfzerstorer]

2BBL? Why

Cost restraints, as well as that I found the reliability part to be better with it compared to single or triple. I dropped the whole V8 part and went for something else for my submission though.

[KLinardo]

Inline 4 are not that light when start to be around 3 liter (my engine weight way more than 200kg / 400lbs). However, I'm not the only one who choose a DW/DW setup with a DOHC 16 valve engine... a bit of Offenhauser engine.
OHV V8 are overrated

but muh pushrods...

I prefer the DOHC setup from today's modern cars, like the 2013 5.0 Coyote in my driveway right now . However, the tech just isn't there for a super durable and powerful OHC motor in '78. You have to remember that most of these cars were being serviced by in-house mechanics. They could build a pushrod motor. I think OHC is just too much for the police mechanics of the 70s IRL, but this is a competition within a tycoon game, so I'm interested to see how those motors fare. Go look at my pursuit variant I posted earlier and you'll see that 500 HP comes through OHC not OHV.

[KLinardo]

Here's the car that didn't make the cut for my side before I made the Gloucester Mayhem 3.8.

The main reason why I decided to scrap this idea?
Dat fuel efficiency. 7.7MPG (US)

At first I was looking at this and thinking to myself: "You idiot... you should have built the 550 CI motor you were thinking about. This guy annihilated you in the power-train department. Great going, that's the one thing you're good at." Then I saw the 2-barrel and the fuel economy and instantly was glad about my decision to go with a smaller V8. I like how balanced the stats are though. It would make a great land barge cruiser for the middle class office worker.

[maxpayne3000]

Inline 4 are not that light when start to be around 3 liter (my engine weight way more than 200kg / 400lbs). However, I'm not the only one who choose a DW/DW setup with a DOHC 16 valve engine... a bit of Offenhauser engine.
OHV V8 are overrated

but muh pushrods...

I prefer the DOHC setup from today's modern cars, like the 2013 5.0 Coyote in my driveway right now . However, the tech just isn't there for a super durable and powerful OHC motor in '78. You have to remember that most of these cars were being serviced by in-house mechanics. They could build a pushrod motor. I think OHC is just too much for the police mechanics of the 70s IRL, but this is a competition within a tycoon game, so I'm interested to see how those motors fare. Go look at my pursuit variant I posted earlier and you'll see that 500 HP comes through OHC not OHV.

my problem with DOHC is theres not much low end grunt

[Lordred]

my problem with DOHC is theres not much low end grunt

Then you are doing cams wrong

[maxpayne3000]

my problem with DOHC is theres not much low end grunt

Then you are doing cams wrong

I just don't like them, because i'm stuck in my ways

[Zabhawkin]

my problem with DOHC is theres not much low end grunt

Then you are doing cams wrong

You actually loose a little in the low end with the higher valve count because you loose flow velocity. However since the engine will also breathe better and carry to a higher RPM you can fix that with lower gears, maybe even come out ahead as far as torque (power) applied to the ground.

[Lordred]

You actually loose a little in the low end with the higher valve count because you loose flow velocity. However since the engine will also breathe better and carry to a higher RPM you can fix that with lower gears, maybe even come out ahead as far as torque (power) applied to the ground.

Which can be tuned with intake runner length, and valve overlap. Another thing you can get into is swept area difference.

Things we do not get to muck about with in the engine builder

[Zabhawkin]

swept area difference.

That one is new to me. I think there was at least one company that tried out shutting down 2 valves at low RPM to keep the velocities higher. As well as a few that worked on variable runner lengths.

[Lordred]

Variable runner length has been a thing for at least a decade.

By swept area difference, I was not talking about making adjustable valve size, but more so into the base design of the valve opening from the get go, intentional partial shrouding the intake valves can make a world of difference in the performance of an engine.

The biggest thing though is the variable runner length, it makes a rather large difference in keeping the air velocity high.

[nialloftara]

Mazda loves variable runner length systems, and from them ford learned the trick. Honda had a 3 stage VTEC system that ran it as a 3 valve at low loads. Those are the most common one's I know of. To a lesser effect butterfly valves on the exhaust act kinda like a variable runner but effect the back pressure rather than the intake flow.

[Zabhawkin]

By swept area difference, I was not talking about making adjustable valve size, but more so into the base design of the valve opening from the get go, intentional partial shrouding the intake valves can make a world of difference in the performance of an engine.

Do you have any links where I can read up on it? Last I heard shrouding was always bad and to be avoided if possible.

[Lordred]

http://www.dtic.mil/dtic/tr/fulltext/u2/408926.pdf It is a boring military study, but it sumarizes nicely what I am talking about.

partial valve shrouding (swirl generation) is more effective than nothing on a stratified charge engine, BUT having a method of creating turbulence upstream of the valve is preferred.

When we transition to all DI engines, than this will no longer apply.

here is an example from Ford on the 2v SOHC engine.

[nialloftara]

Ahh in chamber swirling I thought so, but that's mostly for economy right? Power mods normally go with bigger vales and remove as much shrouding as possible.

[Zabhawkin]

Swirl helps with a lot of things, mostly by mixing the air/fuel inside the cylender and reducing lean/rich sections, which also reduces the chance of knock and pre-detonation.

That combustion chaber is one ugly lumpy thing. Sharp edges where they are intentionally shrouding the valve, the vavle is shouded at the cylender wall, and way too much surface area for heat to soak into.

Edit to add: Wouldn't a DI engine except when its in ultra lean burn mode still benefit from swirl?