Car Enthusiast Club [Now Motorcycle friendly!] - First thread to 150k! ¯\_(ツ)_/¯

[Bitter]

16 minutes ago, Jtalk4456 said:

this might be a weird question, but not sure where else to ask it. 
There's the long running knowledge that current gasoline engines are most efficient around 55 mph. But when we're talking electric engines, is there some peak efficiency speed like that or does it not because it's electric?

That's HIGHLY dependent on a lot of things like coefficient of drag, gearing, drive train losses, and the particular engine and it's power band. My Celica heats peak MPG at 62mph at 2700 rpm where there's a spot in the power band that's really efficient. Typically the higher the manifold vacuum the better the MPG but that's only a gas engine thing and only for ones that run with a throttle body.

 

Electric cars it's more a function of just coefficient of drag and drive train losses as speeds increase.

[Jtalk4456]

1 minute ago, Bitter said:

That's HIGHLY dependent on a lot of things like coefficient of drag, gearing, drive train losses, and the particular engine and it's power band. My Celica heats peak MPG at 62mph at 2700 rpm where there's a spot in the power band that's really efficient. Typically the higher the manifold vacuum the better the MPG but that's only a gas engine thing and only for ones that run with a throttle body.

 

Electric cars it's more a function of just coefficient of drag and drive train losses as speeds increase.

so in a way gas cars efficiency is mostly limited by the motor, but on electric vehicles, peak efficiency varies more on the efficiency of the physical car design, weight, drag, etc?

[Lomac]

10 minutes ago, Jtalk4456 said:

wow that's pretty low. I mean still overall elec is good for sure, but that's not what i expected. So how would that work with the eventual move to electric mass transit, electric trains buses and all that? Actually trains not as much with moving to maglev and hypertubes over time, but still

Buses are probably one of the best use cases for EVs.  They're generally kept to low speeds throughout sprawling cities/urban developments and can potentially use wireless charging pads at their longer stops to get a quick boost of range.  Power from overhead lines for EV buses have been a thing for decades as well. 

[arnavvr]

10 minutes ago, Jtalk4456 said:

so in a way gas cars efficiency is mostly limited by the motor, but on electric vehicles, peak efficiency varies more on the efficiency of the physical car design, weight, drag, etc?

Gas car efficiency is VERY dependent on gearing. I really wish I had a 6th gear in my car, doing 90-95mph is 4000rpm +

[arnavvr]

1 minute ago, Lomac said:

Buses are probably one of the best use cases for EVs.  They're generally kept to low speeds throughout sprawling cities/urban developments and can potentially use wireless charging pads at their longer stops to get a quick boost of range.  Power from overhead lines for EV buses have been a thing for decades as well. 

Buses are probably long enough as well to have solar on top of them, which could charge the batteries throughout the day.

[bcredeur97]

1 hour ago, arnavvr said:

Gas car efficiency is VERY dependent on gearing. I really wish I had a 6th gear in my car, doing 90-95mph is 4000rpm +

Lol I don’t cruise faster than 82 or so in my Miata. That’s where it’s at 4000 rpm in 6th gear 

 

I think it goes open loop for anything beyond 4000 rpm. Old ecu thing 

[GDRRiley]

On 3/30/2021 at 6:09 PM, arnavvr said:

I'm pretty sure timing belts aren't that expensive; it would probably be worth it to just test it out and see if the thing works.

timing belts are something that I've decided I should do often in my civic. instead of 100K miles at 50k because it isn't much and I tend to be a bit rev heavy.

[arnavvr]

4 hours ago, bcredeur97 said:

Lol I don’t cruise faster than 82 or so in my Miata. That’s where it’s at 4000 rpm in 6th gear 

 

I think it goes open loop for anything beyond 4000 rpm. Old ecu thing 

That's really short gearing lol. What's the top speed of the car?

[Tonyx]

7 hours ago, Jtalk4456 said:

There's the long running knowledge that current gasoline engines are most efficient around 55 mph.

Not really

Usualy Is lower for smaller and less powerfull cars

On mine is around 60 kmh on 5th gear so engine under 2000rpm 

Depends by engine, size, gear ratio, drag and tires.

 

Of course engines had a range of better efficiency compared to engine load but a much longer gear ratio increase speed and higher speed increase much quickly aero drag

[bcredeur97]

5 hours ago, arnavvr said:

That's really short gearing lol. What's the top speed of the car?

The JDM ecu limits it to 112. But on the usdm one I’ve had it up to 123 back when I was young a stupid lol

 

i don’t know what speed gearing runs out I think it’s around 130 or so 

 

funny thing is this is with the 3.9 rear end... most miatas came with a 4.1 rear end so this is longer lol. There’s a very rare 3.636 rear end some ppl put in, but it’s hard to find. 

[jagdtigger]

11 hours ago, bcredeur97 said:

Lol I don’t cruise faster than 82 or so in my Miata. That’s where it’s at 4000 rpm in 6th gear 

I would stay below 3800 if i were you, anything above that severely shortens the lifespan of the engine. My golf has 5 gears and hovers around 3000 when im going at ~90 kmh 5. gear...

[JoaoPRSousa]

13 minutes ago, jagdtigger said:

I would stay below 3800 if i were you, anything above that severely shortens the lifespan of the engine.

 

Imagine having a redline of 7000RPM in a mass produced engine

Oh wait

[jagdtigger]

5 minutes ago, JoaoPRSousa said:

 

Imagine having a redline of 7000RPM in a mass produced engine

Oh wait

On mine it starts at 6500, mechanic still said i should stay bellow 3800. And he certainly isnt a dabbler so most have good reason to  say it.

[JoaoPRSousa]

1 minute ago, jagdtigger said:

On mine it starts at 6500, mechanic still said i should stay bellow 3800. And he certainly isnt a dabbler so most have good reason to  say it.

 

I'm just saying they wouldn't come out of the factory with that high of a redline if it "severely reduces" the lifespan of the engine. Pretty sure that wouldn't pass on a quality check. But hey, I'm no mechanic, so take this with a big pile of salt. /s

[vetali]

I thought this was the car enthusiast club, not the granny's sunday stroll to church club.

[PandaCopyRight]

53 minutes ago, jagdtigger said:

I would stay below 3800 if i were you, anything above that severely shortens the lifespan of the engine. My golf has 5 gears and hovers around 3000 when im going at ~90 kmh 5. gear...

I mean if its maintained and serviced properly it shouldn't have any issues in any RPM until the redline and should still be like new 

[Bitter]

1 hour ago, JoaoPRSousa said:

 

Imagine having a redline of 7000RPM in a mass produced engine

Oh wait

Peasant. 7800 red line, 8000 fuel cut, 20yrs old.

[Bitter]

13 SRX runs poopy. Lol!

[PandaCopyRight]

9 minutes ago, Bitter said:

Peasant. 7800 red line, 8000 fuel cut, 20yrs old.

i think my cars redline is like 4500
its 5 years old

[JoaoPRSousa]

Now I'm seriously doubting if these posts are April's Fools material or not

[bcredeur97]

3 hours ago, jagdtigger said:

I would stay below 3800 if i were you, anything above that severely shortens the lifespan of the engine. My golf has 5 gears and hovers around 3000 when im going at ~90 kmh 5. gear...

Eh it’s a Miata it’ll be fine. 
 

engine blows up you put a new one in it and keep going 

 

it’s the easiest car I’ve ever worked on so actually don’t mind as long as I have another car to drive lol. The engines aren’t super expensive either 

[bcredeur97]

3 hours ago, vetali said:

I thought this was the car enthusiast club, not the granny's sunday stroll to church club.

hey ill go over 4000 rpm every now and then at home. I was more referring to long interstate trips lol

I miss autocrossing. I wish vehicles that can tow miatas were affordable. takes all the stress of breaking your car 150 miles from home away

[PandaCopyRight]

18 minutes ago, Benji said:

In which case it's a diesel.

Spoiler

SHHHH DONT SPOIL IT GOD DAMMIT

 

[the gamer that is bad]

Nitrous it then

1 hour ago, PandaCopyRight said:

i think my cars redline is like 4500
its 5 years old

 

[AlwaysFSX]

4 hours ago, jagdtigger said:

I would stay below 3800 if i were you, anything above that severely shortens the lifespan of the engine. My golf has 5 gears and hovers around 3000 when im going at ~90 kmh 5. gear...

Gotta hit redline on the on-ramps to shake the mud out of the frame

3 hours ago, vetali said:

I thought this was the car enthusiast club, not the granny's sunday stroll to church club.