I'd rather watch modified versions of an engine I can own myself. F1 cars might as well use jet engines since they use such drastically different technology.

 

Don't kid yourself, there is tons of technology in the N.A.S.C.A.R. world. The alloys and materials used for diffrent components are incredible and the cylinder head and camshaft technology is ridiculous. Remember, most of us here are most akin to the roller cam, these engines run with a flat tappet camshaft with nearly 1" of valve lift and still manage to spin over 9000RPM for what might as well be an entire day. Believe me, there is some technology there for sure. We build some pretty bad little engines for our local circle track guys and even a Super late model is a pretty impressive piece, making 450ish HP from 360" through 2 1.5" holes in the restrictor plate is a pretty tricky process!!

-Bryan

 

Wow OVER 100% volumetric efficiency would mean you would have to stop every once in a while to drain some fuel out of the tank right?

 

Humm, no....it would mean you'd have to stop sooner to fill up the tank.

 

Nascar engines are very efficient engines, between the cam timing, and alot of R&D in headers/exhaust scavenging. They are limited to carb size, and they make alot of power with a small carb. I had a friend that worked at a nascar team engine shop. They dyno'd one of the engines with my 1050 CFM Braswell Dominator, and it only gained 15 HP across the board. For almost double the airflow capability, it wasn't a huge gain in power.

 

volumetric efficency = how much air is placed in the cylinders vs. actual displacement of engine

 

Well that's how some of them do it the old fashioned way. Either way they all cost a arm and a leg.

 

I do not believe the 12:1 is the limit on comp. I think it is much higher. The engines do not make 750 hp with the restrictors in the carbs. The information about the 1050 carb making 15 more hp is not even close to correct. One of the top teams bolted on a larger dominator (unrestricted) on one of the cup cars and the speed went from 178 to 230 and that was without tuning the carb to the engine. Those cars are incredibly aerodynamic and will go 200 mph with 500 hp. I have read that the exhaust systems are so good that they get a very good pull on the intake charge because of the vacuum effect the exhaust creates. They are not as complicated as F1 but probably have more tricks applied, do to the same basic engines for past 30 plus years were as F1 rule changes make them start over every decade or so.

 

just to give you guys a taste, in one of our schools project motors. Romco late model series motor. (Bowtie block and bowtie heads, 390 cfm carb, carillo rods, custom cut JE's 9:1 compression) spinning to 9000rpms makes 604 hp on the engine dyno. It is basically a mini cup motor. Cup cars do not run near the 13 or 14:1 compression ratios like they used to. I believe 12 to 1 is where they are at now.

 

12.00:1 compression ratio is the limit in the rule book. The 15 HP gain was on a dyno engine, using a stock Edelbrock SB2 intake with the dominator adaptor. No carb tuning, with it setup for my drag car. The cars can go alot faster than 200, but the body template and spoiler rules for the races limit them.

 

Dont forget the NHRA pro stock trucks ran basicly the same engine except 2 dominator carbs on a sheet metal intake and made over 900hp.

 

Damn right! Those were some IMPRESSIVE motors!

 

12:1 is the rule... period

The Cup motors are on par if not more complicated in some areas compared to F1 motors, actually they are suprisingly similar.

F1 rule changes force the teams to change the motors yearly. Over the last 4 years they went to unlimited engines per weekend, to one engine per weekend, to one engine for 2 weekends to now dropping displacement from 3.0L to 2.4L. Not to mention the little things in there like rules on the materials used in the motors and the banning of variable length intake manifolds.

Them Pro Stock truck motors also tried to run the Splayed Valve heads, what junk they are.... that's why the Little Chief heads were designed.

Bret

 

DanO, you are very correct about optimizing components. That works for every good engine.

Look at the BMEP at power peak rpm for F1 (183 cu.in.), NASCAR Cup (358 cu.in.) and Pro Stock (500 cu.in.) engines. You might be surprised how close they are, and which has the highest.

BMEP (Brake Mean Effective Pressure) is a good measure of how much an engine gets out of the air it pumps. IOW, it indicates how much torque the engine gets to the flywheel from each cubic inch of displacement. Because hp = torque x rpm (and a conversion factor of 1/5252 to get the units correct), it's very important to get the highest torque/cube and then go for rpm while not losing much torque/cube as you up the revs.

Of course doing it at near 20,000 is much more expensive than doing it nearer 10,000.

 

Comparing a ps/t motor to a cup motor is well...kinda like comparing a new c6 to a vw bug. Cup motors by design are technology limited. The effective teams are spending more money using the power they have, and making it durable, then trying to make more. You can make all the power in the world off of the plate, but if you are racing restricted, all bets are off. If you are racing in a bowl, all the power does little good, while recovery is king.

Imagine how fun nascar would be if they could use un-restricted 500" P/S motors....I might actually watch then!


Dennis

 

I don't think those chassis would be able to deal with that kind of power and would make for a bunch of high speed bumper cars, ha ha. Would be more exciting though, that's for sure.

 

And a solid-roller camshaft.

 

PST engines used to make closer to 975 - 985.

 

Its called unlimited R&D budgets. When I first went to work for Stef's we had just finished 3 x R&D pans. These were for testing only and not legal by todays standards but they were built to help understand other things going on. Cost was $9000. They aren't scared of failure down there so they will try stuff, even if it is off the wall.
Even the oil pan has specific guidelines that we must follow or the pan is deamed illegal. 1/8" of an inch more depth can mean more power.

Sweeping engine rule changes will take place in '07. Stay tuned.

 

What changes?