Midnyte81

On another note, Large bore + short stroke = High rpm and midrange torque. So why don't more people drive destroked and bored out 350s and 400s? The reason I ask this question is that the New Ferraris have a bore similar to the Chevy 400s and a stroke similar to the old Chevy 289s. (Large bore + short stroke = High rpm and hp) If I were to acquire a 400 block and bore it 4.155 (Given that I have aluminum heads and a hell of a cooling system), put a 289 forged crank and bottom end parts in it, put ported and polished Pro TopLine 50cc castings that support 200 or 220 cc intake runners (2.02/1.60 valves), get a hell of a top end (Preferrably Lunati or Comp Cams), put a raised single plane with dual 4 barrels, and match it all up to a built T56. would that be the Chevy equivalent, or is it wishful thinking?

Air_Adam

People don't do it because a 400 can still make more power than any short stroke engine based on the same block.

And an engine like you are talking about (BTW, chevy's engine was the 283, not 289) would be a DOG below about 4000 rpm, just like those Ferraris are.

MrDude_1

if you took a "New Ferraris" engine, and stroked it... and then spun it to the same RPM anyway, it would make more power.


with a 400, why would you destroke it, only to make less power?
the max RPM you could spin it would still be the same... they'll both rev so fast that you couldnt tell the diff in speed (obviously they'll sound diffrent)... the only thing is, you make more power with more displacement.



THATS the reason you dont see destroked 400s very often... its only classes that have a cubic inch limit, and the occasional mislead person that have destroked motors.

ljnowell

More CI = More potential. Thats the bottom line.

Midnyte81

It makes a lot more sense that way. My apologies about that 289 mistype. (That's Chevy blasphemy!) I love my stroker, but someone told me about that theory. I know 427s with the right parts can be spun to 8500+ rpm. Is the same possible for the 400? If I do this, keep in mind this won't be a daily driver, so I won't really need low end torque.

Midnyte81

Also, more cylinders = more hp. Look at the Diablo. Perfect example. Hmm, on another note, why doesn't Chevy make an exotic 10-16 cylinder engine that is like 5.7 liters? Perhaps even bring back the LT5 engine and tweak it to supercar potential.

blyth18md

more cylinders = more hp....i dont think so. If the number of cylinders produce an increase in displacement the potential for HP goes up...

Reason they dont produce exotics...
more cylinders = more parts = more money

MrDude_1

because every time they think they need to do somthing super to make more power, they find they only need to tweek the genIII a little more to meet their goal.

ShiftyCapone

iTrader: (7)

Close but a bit off. It just makes for a more balanced engine with less rotating mass per cylinder. Basically, that increase in stability allows for higher revs because each cylinder has less momentum. Multi cylinder engines are created to reduce primary and secondary forces inside an engine. Complete cancellation is possible with V12 and V16 motors and the engine becomes more harmonic. Much greater than a V8. Chevy doesn't need to make an exotic engine because what they have works and is cheap to develop and produce. Not to mention the space contstraints and minimization of parts.

Rembrandt

more cylinders for the same displacement, not OF the same displacement CAN make more power.

for a given displacement more cylinders means smaller cylinders which are more efficient burn-wise (everything is closer to the plug) and have higher rev potential due to lower mass.

Once volumetric efficiency is maximized and the engine is tuned, you can't make any more of the torque component of horsepower; so if displacement is limited you can only rev higher to gain power.

Hence F1 cars making 900 horsepower with 260-300 lb-ft of torque, not because of magic, but because they can't fill the cylinders any better, so they build an engine that sustains that volumetric efficiency at higher RPM.

Next time you hear some local race engine builder wannabe lure you with the mystique of "trick" race car style setups...

...tell him to STFU .

Rembrandt

who, GM?

also no market or brand&image credibility for exotic car range.

daverr

iTrader: (1)

F1 car have great volumetric efficiency.Formula one cars of the late 70s (sorry i dont have present specs) were only 3.0 liters ,which explains why the torque was at the 260-300lb level.They made 520 hp @ 12300 rpms ,i dont think they had problem with cylinder filling.I wish i had 350 sbc with F1 technology ,id be making over 1000 horsepower(no replacement for displacement).

Rembrandt

WTF?

I said nothing to the contrary that they have the highest VE of any road race natural aspirated engine made!

You hit a brick wall or asymptote of how well atmospheric pressure can fill the cylinders once you have the ports and manifolds and valves and cam timing perfect;

so to make more power, you have to go with higher revs because VE is maxed out.

F1 cars now STILL make 260-300 lb-ft and they are 3 liters, but can breathe very well at high enough revs to make 900hp.

Midnyte81

Here's the market and brand&image credibility for exotic car range. I almost forgot about this one.
Never say never!:lala: :lala:

Midnyte81

Here's the pic.

Rembrandt

v16s

DemonKnightDK

Dont know if you guys new this or not but GM is currently working on making a V10 based on the LSx engine... they are also making a new DOHC V8 to replace the northstar...

five7kid

iTrader: (14)

Making power is all about pumping air/fuel. The more you pump through and combust, the more power you make.

You can do that by increasing the volume of the air pumped through the engine in each revolution, or you can increase the number of revolutions occuring in a given unit of time - either one works, both have their drawbacks. Since Chevy has always had pushrod operated valves in their production V8's, increasing the revolutions per second has always been an expensive proposition.

Since this doesn't really relate to the technical details of swapping engines in a 3rd gen F-body, which is the purpose of this forum, that will have to be the last word on this thread.