OK. From what is known, NASCAR engines are making around 750+ HP. Some people on this forum say they are running ungodly compression ratios. No they aren't. They're limited to 12:1. They must have a cast iron block and have a choice of aluminium heads or cast iron. The engines are around the 350-355ci mark right? Aren't the combustion chambers limited to 61CC? ( I know they are limited), Cam specs are limited etc. I know items such as the oil gallery are polished smoothe for improved oil flow, etc.
But in all possibilites, it's impossible for a 350CI engine to run the HP they are running N/A right?? Engine masters are only making 600HP and up with a max restriction of 366ci in the small block competition. Although they are restricted to pump gas. But still, John Kasse was running in the upwards of 35 degrees of timing on his winning pull (it was detonating though, but that's why he has coatings).
Am I missing something?
Thanks,
Philip S.

 

umm good ?.... I would have said High Compression.

 

A "NASCAR" motor makes 750+ RWHP 358ci N/A because the teams have millions of dollars to R&D.Teams may run any bore and stroke as lons it fits in the 358 dimesions..cams are open as well heads blocks and manifolds are supplyed from the teams praticular MFG as well as serious technical support.

 

358 cubes is correct. Max bore is about 4.180 or so, so strokes are down around 3.3. Max power on open engines (not plate) probably comes in the high 8's and holds on without dropping much past 9500. It depends on the track and rpm range. Martinsville today showed about 4500-9000. Some track have a gear rule imposed to limit rpm to maybe 95-9700.

The secret is making great BMEP at 8700-9500. IOW, pumping lots of air at those rpms. Cup engines have to use flat lifter cams. 9700 isn 't all that much problem for them now, but it is ungodly expensive to do.

 

if you have a set of heads that can flow 500cfm and you rev it to 10krpm, you can make a ton of power.

also are you sure on the compression? They are spinning these motors pretty high, nothing like IRL cars though

 

The amount of R&D in the engine is ungodly. I am not sure how true this is, but I have been told that they don't have any bearings in the bottom end of the engine. Everything is polished extremely smooth, and the tolerances are of course very close.

 

From what I've heard is that they spend millions on just the head design.

 

Yes theres bearings....babbit type main and roller bearings for the cam

 

First off start off with a SB2.2 Cylinder head. 400-440cfm is easily doable out of these castings for these teams. The chambers aren't limited at all, they are in the 30-40cc range with flat top pistons and have extremely good burn and timing settings in the mid to high 20's. 2.0:1 rocker ratios and .750-.800" lift teamed up with a 2.180" intake valve. Throw in there lots of work to get the intake manifolds and headers perfect along with everything else and these power levels aren't hard when you have 3-4million dollars a year per team just to spend on motors.

Bret

 

There is sort of a rule of thumb, originated I believe by Air Flow Research, that the max power potential of a 2 valve/cylinder V8 gasoline engine is about 2.0 x CFM (intake port CFM at max lift). This is a "give and take" number, of course - bigger displacement motors will tend to make a bit more, smaller a bit less, compression ratio is a factor, etc.

For a smaller displacement engine with a high flowing port, the only way to actually take advantage of the available air flow is to rev the heck out of it, as has already been noted in this thread. Not so for a bigger displacement motor. My '67 has a 548 CID big block, with heads that flow about 380 CFM at max lift, and makes 618 RWHP (about 730 crank HP) with a very streetable cam.

The Engine Masters competition is another thing altogether. First, they can't )(by rule) use the kind of specialized heads that the Cup motors do. Just as important, the competition is about average power from (I think) 3000 - 6500 RPM. A Cup motor would lose that competition, badly, because they're designed to run from about 7000 to 9000 or so. But because HP is a function of torque and RPM, they make more power at those higher RPMs.

 

The cams are expensive! On the order of 1000$+ for just the cores The lobes are welded to be able to withstand the abuse they take

 

Hmm, I remember reading a book that explained the motor specs. I could swear that the chambers were limited as well as the valve sizes. However, you are from a very experienced field so I take your word on it.

 

I thought it was max power numbers? They added the peak HP and TQ together to get a final score? I'm probably wrong.
Philip S.

 

Known as Hardsurfacing in the welding world. Wow, There's more to these engines than I was lead to believe.
Thanks for the discussion guys!

 

They use belt driven oil/scavenge pumps to create vacuum in the crankcase, they reduce tension of the rings, especially the oil scraper ring, gas ported top ringlands, oil squirters to cool the bottom of pistons, oil squirters to cool the valvetrain at 9000+ RPM, smaller bearings (Honda size) to reduce bearing speed, belt driven cams, huge solid lifters to reduce stress on cam lobes at high RPM, and ungodly amounts of money in the heads. There are creative little things you can do on track to to make a little extra power also. It's only cheating if you get caught.

 

like others have said, theres a ton of money for R&D in nascar. one of the main reasons why there is such a huge ford gathering for aftermarket parts- they have all those ford series.

i forgot where i read it, but they grind hundreds of cams and heads and just toss them out when they dont make the power of the previous "best" cam or head setup. must be nice to have that kinda research at your disposal .

 

Only thing I know is an altenator and set of headers that we run on our Craftsman truck motor is more money than I have in my 408.... I do also know a cam and set of lifters for a cup motor is about 6 grand...

 

What NASCAR spends is nothing compared to F1 teams. They spend millions upon millions just in engine R&D, not to mention the chasis. The F1 guys are using memory alloys for their cams, that when hot the cam lobes grow, and then upon cool down they go back to their original specs.

the cash they have on hand to spend is inconciveable, and there are hundreds of teams that are spending like that too

 

And nobody mentions F1 cars?

If you want to be amazed by engine technology take 3.0L NA (183 cu in) and put out 900+ hp and pushing 20,000 rpm

Its all about optimizing all of the components to work together. You can actually design engines to create over 100% volumetric effiency without forced induction.

Not to be a stick in the mud, but nascar engines do not have the enigneering power (and $$) behind them like F1. But the nascar rules prevent technology from filtering into the sport of carburation and 9" rears... (zzzzzz)

 

I would like to see some cam specs on these. I drove a stock car in Florida last year, a SBC making 650+ HP and the lopiness at idle was shaking like crazy. Idle speed was between 900 and 1800 RPM, just flucuating back and forth. What a blast to drive though!