Can someone please explain how small displacement engines e.g. GT2's 3.6l flat six, can push out 520 odd bhp with room for tuning and other car manufacturers 'need' more cylinders and generally more displacement to reproduce the same figures?

If it is possible to push smaller engines for this much power why wouldn't we see more high performance cars with these lighter engines?

 

Preachin to the choir my brotha.

T--U--R--B--O--S

We need um.

Blowers got the torque grunt, but you can't beat the turbs for that high hp.

 

Think about it. How long will a motor making 150 hp/liter live compared to one that makes 90-100 hp/liter? No brainer.

 

omg....out of all the motors you just have to pick the GT2 and you think is just a flat 6?

 

The GT2 just came to mind, there are many other engines that could have been considered; but I agree that may be an extreme case.

I'm surprised to hear that longevity would even be considered as a reason not tp push an engines capabilities more than they are currently. With proper cooling and reinforced internals I would imagine engineers could safely create engines that 'could' last just as long as a camry's, with proprer maintenance.

 

The largest forces on a motor are reciprocating (by some margin) ... I.e. the inertial loads on the internals...

A high output low revving engine will always outlast a higher revving variant. Long live the V12TT... !!

Take a 600hp truck revving to 2.5k rpm vs a 600hp racing motor revving to 15k rpm...... how many miles you reckon each is good for? 300k vs 500?

As the power pressure pulse increases this does place more strain on the motor but not nearly as much as increasing revs 1000rpm for example. Also the pulse has room to disovle down the cylinder, but as a piston reaches TDC the strain on the conrod is emense... and does not dissipate as a energy pulse does. Obviously if you get the pulse timing wrong (detonation) your engine is going to implode pronto....

100k miles on an M5 will have one very tired motor, 100miles on a V12TT for example will not be anything close to as worn out. The one revs to 8500 the other to 5000?. In its life time the M's motor has done nearly twice the amount of cycles over the same distance driven, all else being equal, and assuming the rev range is used proportionately the same which may not necesarily be the case gvn the very high low-down torque on the V12 and the relatively higher torque peak of the M motor.

 

Thanks for the insight Steve. By that reasoning I would imagine high compression, high revving cars would not be suitable as long term DD's.

I don't think I agree with AMG holding the mercedes philosophy of creating 'long-lasting' engines by sacrficing performance. If an AMG car could be made to have a more potent engine with a shorter lifespan, (or simply larger maintenance expense), I believe consumers would be more prone to purchase, rather than having these N/A engines with more linear power bands and longer lives.

 

Yep I had a few in the past and they are tiring to drive and generally more noisey too boot.... but on the track its a different ball game...!!!!! N/A cars generally easier to drive on tracks since their power delivery is more linear and progressive... heavily boosted cars tend to be very binary with power but they have come a long way from the old days.

 

Correct. A high specific output almost always entails spinning the motor faster. If you want a long lasting motor, keep the revs down. This is why you can realistically get 300K+ miles out of a Cummins, but the V10 in the M5 will be scrap metal years earlier and an 8 liter Hemi funny car motor making 5000 HP comes apart after every pass. Customers always want more power, but they also want the motor to last longer than the warranty period. AMG does not "sacrifice" performance to get long life, they build larger, less stressed engines that still make outstanding power. The 5.5 and 6 liter V12's make 500-600+ HP. Both the 5.5 Kompressor and NA 6.3 make 500+ HP. I don't see any sacrifices there.