Observations regarding NA I4 vs V6 engines

[Chris B.]

Originally Posted By: John K
On the supercharger vs turbocharger comparisons in 2007 the MiniCooper S changed from a supercharged engine to a turbocharged one. They also changed the engine supplier... It would be interesting to know the reason for the change, I haven't found a detailed discussion. From the web site I got the following (easy to do because the Cooper S convertible still has the old engine, but it messes up the weight and performance comparisons...). Engines have the same bore and stroke, and the latest one is direct injection.

Supercharged: 168HP@6000rpm, 162LbFt@4000, 16.4LB/HP, 134mph top, 7.0 sec 0-60.

Turbocharged: 172HP@5500rpm, 177LbFt@1600-5000rpm, 15.5LB/HP, 139mph top, 6.7 sec 0-60.

The most surprising part to me is the flat torque from 1600 to 5000 rpm.


168hp on a supercharged/turbo engine....how lame is that? Why even bother when you can just through a gerbil under the hood and get more power.

 

[ikeepmychevytoo]

I remember the days when the overheating was a major problem on sustained high speeds, especially the smaller Europeans. They may never boil the coolant but as the cylinders expanding they simply couldn't keep the performance even they initially could. Specifically Fiats 1.3, 1.4, 1.6 were very prone to this. Even newer smaller engines from 90's from various makes are not far better than those. While they can keep such a speed, after a long drive one may notice some consumed oil.

V blocks have more proportionate x y z dimensions. Their amorphous shape may make contraction/expand related thermodynamic analysis very difficult but once this engineering festival is done you get a stable powerhouse.

Ford's German V4s were popular here. They were avaible in probably all the model spectrum Ford was producing in Germany, including the Ford Transit (Europe and Britain's Econoline/ workhorse van). Like advertised in brochures, they would never oveheat and could keep the performance. Sound was almost like a v6.

My driving observations for the v-6 vs. L4: Usually v's have more cooling capacity, they take longer to reach a completely warmed state. Once warmed they are very stable, with a temp gaugae that I could track the thermostat actions I can say that thermostat is trying to keep the engine warm at speeds. Speedier the car the cooler the native intention of the engine. On L4's, after a certain load and speed especially at the long up-hills you'd better watch the needle. V's -if they must- tend to overheat at the idle. Stop and go is the hardest time for a V because, in proportion to the block, radiator capacity is at question then.

Also per the combustion theory, minimized thermal sink possibility diverts the possibility towards the motion. So it is thought that, ideally, while the cylinders preferred as hot as possible and the outside of block as cold as possible. Given the thermal and strength demands v's are at advantage in design phase.

If conditions let me a vee (like not strictly stop-go traffic or particularly lightweight) I'd personally prefer it for overall well-balance.

 

[Jethro]

Originally Posted By: Chris B.

168hp on a supercharged/turbo engine....how lame is that? Why even bother when you can just through a gerbil under the hood and get more power.


The car is small, doesn't need 200+ horsepower. It still gets decent fuel mileage, has more than enough torque, and has less stress on the engine and forced induction systems.

I don't think it's lame at all.

 

[javacontour]

100hp/liter is seldom lame.

What is lame is thinking that the ONLY way to performance is large displacement.

There are many paths to speed, smaller, lighter cars with small, force-fed engines to larger cars with huge displacement powerplants.

There is room in the world for all of these.

What I find the most lame is a closed mind.

 

[ThirdeYe]

It's all about the power-to-weight ratio

 

[XS650]

Originally Posted By: ThirdeYe
It's all about the power-to-weight ratio

That's true if all you do is drive on boring roads.

Wrestling a pig around a twisty road is a lot less fun than driving a nimble handling car on a twisty road.

edit: I think we agree.

 

[Drew99GT]

Factory boosted vehicles, especially turbocharged ones, are severely detuned so the vast majority of owners who WILL use 87 octane craap gas and rarely change the oil, etc. etc. etc. get that extra 50,000 miles out of em before they blow up.

Get a boost controller and turn it up a bit, along with an ECU upgrade unleashes insane power increases for such little work.

 

[BuickGN]

Originally Posted By: Drew99GT
Factory boosted vehicles, especially turbocharged ones, are severely detuned so the vast majority of owners who WILL use 87 octane craap gas and rarely change the oil, etc. etc. etc. get that extra 50,000 miles out of em before they blow up.

Get a boost controller and turn it up a bit, along with an ECU upgrade unleashes insane power increases for such little work.


That's the beauty of factory FI cars. On good gas, 21psi, and a chip, I took a second off and added 6mph to the factory times.

 

[gtx510]

I here ya, upgraded turbo cars are a blast.

Regarding the boosted Mini engines; torque is what accelerates a car and it takes a Honda K24 to out-torque the old s/c Mini engine.
That's not too to bad for a 1.6L w/ 11.6psi from a positive displacement (roots) s/c and a tiny intercooler.
I wonder what upgrading to a Eaton MP-series s/c would do.

http://en.wikipedia.org/wiki/Tritec_engine old
http://en.wikipedia.org/wiki/Prince_engine new

http://en.wikipedia.org/wiki/Honda_B_engine
http://en.wikipedia.org/wiki/Honda_K_engine

 

[Auto-Union]

A lot of mfgs are going back to 5cyl. The I-5s I deal with are great engines. A turbo I-5 is ideal.

One advantage of the V6 (v-inline) is packaging, to put the 6 in the space that normally takes a 4, a Golf or Jetta for example. Another advantage is the single cylinder head, making for less expensive manufacture.

 

[Auto-Union]

iirc, there is a VR4 and maybe a VR5.