More Power muahahahahahahahaha

[Highspeed]

We are all talking from different frames of reference here, which is going to get complex
We have street cars, racers and dragsters all competing together

All-aluminium engines work fine for street and racing cars with a caveat that I'll get to in a minute. For 1/4 mile engines I'll just take HTRN's word on that application.
The problems with aluminium engines are often caused by the end user :- The engine overheats due to water pump or rad failure. The owner is in a hurry to get moving again and refills the system with cold water causing thermal shock. The steel cylinder liners shift due to the co-efficient of expansion that HTRN mentions and that's all she wrote. Major killer of the Rover V8 family of engines.
I think it was Porsche who pioneered the integral aluminium liner with a proprietary electro deposited chrome steel coating, although I could easily be wrong on that. BMW have been using it for decades and I'm familiar with it via high performance 2 stroke bike engines. It's a great system but one more step down the road towards sealed throwaway engines because it's very difficult to recondition.

Regarding the overhead cam design, I'm still not convinced by two big valves and I don't think I ever will be. I spent too much time trying to get power from these kind of engines in motorbike form, where you don't have the option of simply adding more cubes or using forced induction.
I recently got my hands on some professional engine simulation software ( I'm not saying what exactly, because I didn't pay the $15k asking price for it ) and I'm learning to use it by running simulations of engines I have already tuned in real life ( I kept notes, because I'm weird like that )
Those twin valves, the resulting combustion chamber shape and the limitations on compression ratio are a massive bottleneck. Plug in a 4 valve pent roof chamber and the gains are enormous, without a commensurate rise in fuel consumption.

[HTRN]

Try comparing the low(as in under 5000RPM) performance - The typical limit for street motors for piston speed is 4000ft/min, that's 5300RPM with a 4.5"(114.3mm) stroke. Which means peak power should be less than that.

Play with your software, and see what happens for motors running under 4000RPM. I think the results may surprise you - the issue with the 4 valves, Hemis and wedge designs have been known for decades, and in the US, at least, it's a big money industry to squeeze every last cfm out of a intake/exhaust port. One of the better engine design programs I've heard of was The Engine Expert, which went for stupid money($500) in the early 90s. Apparently, it's still available, and has been updated. The lack of pricing on the website makes me suspect it hasn't gotten any cheaper. Do keep in mind, that flow rate(cfm) isn't everything, port velocity is very important too - simply hogging out the ports to the max possible before you hit the jackets will give you lots of flow.. Along with low port speed, which can lead to all kinds of headaches. The new LS style ports take everything that's known about port design, and incorporates it - Head porters have known for decades that tall narrow ports flow better, and incorporate them. Typical flow numbers are so high, that I generally don't see higher flow rates except in Race hemi heads, or Dart Big chief heads, neither of which can be thought of as destined for street strip duty.


HTRN

[ButchS1066]

The way we do things south of the Mason-Dixon:

39BB.jpg

[Darrell]

I recently paralleled a souped up ricer (Subaru) on the highway, the car was chirping, whistling and tooting like a steam kettle about to explode, plus it had a raucous exhaust note. I've heard similar noises coming from rally cars on TV and such. I know ricer racers are squeezing lots of horsepower from small engines, how are they doing it? Also, I assume that though they're getting lots of HP, they're not getting the torque of larger (V8) engines. ??? I remember when Subarus were gutless wonders. What's changed?

[rightisright]

I know ricer racers are squeezing lots of horsepower from small engines, how are they doing it?

Turbos and tuning. That hissing and chirping is the turbo blow-off valve. Some of those Subarus and Mitsu Evos are pretty damned fast. There are some out there that can beat me, but I haven't met one yet! 450 HP and almost 500 ft/lb of torque in a Eurosedan can really boogie.

Now that older twin-turbo Supra I raced was another story. That thing ate me alive. When I caught him at the next light, he told me he was making 800 HP at the wheels And I believe him. It took off like a Hayabusa!

[HTRN]

The way we do things south of the Mason-Dixon:

How we do things in "Nu Yawk"
And no, it's not mine.

Note the numbers: 604CID, pulling 8.94@153MPH.. Also, it has license plates. It's not the only really fast street car here - there was a monster shoebox Nova, and the infamous "Redbird", that did 9.30s at E-town on slicks, using 2 stage NOS, and a 530inch motor.

The guy who did the chassis work used to have his tubbed Cavalier out in front of his shop over on Veterans Road West..


HTRN