engine horsepower

[go-vee-or-go-home]

wondering what horsepower the engines are running , i know stock is 40 hp. what is the range for a reginal engine and what would it be for a national engine. what is the top horsepower getting out of the engines.
thanks for your time
Colin

[smsazzy]

not an easy answer because there are so many variables but the conventional wisdom says 53 to 58 with rare quotes about 60 or more.

[brian]

Didn't realize when I used Stephen's laptop to make the above posting that it would come up under his name. The posting is mine and does not necessarily reflect his opinion.

[SR Racing]

Brian (Using Stephen's computer) and Stephen, are correct in regards to the numbers that are thrown around. I would be wary of ANY numbers.. We have 2 engine dynos and a chassis dyno... We have dyno'ed literally hundreds of engines (new, used, fresh, broke-in, ours and several other builders. I have never seen one actually produce 60HP with any statistical validity. It might bounce on 60 during a run, but it was usually due to a jitter in the water brake pressure or throttle. I am assuming the above with SAE correction factors. Since builders have a plethera of dyno brands and different calibration routines, etc. their numbers will vary.

Also, the peak HP number alone isn't going to put you up front. Producing 60HP at 5100 RPM (where most peak) won't do much for you if you have 45HP at 6400. The intake, heads and carb flow and cam timing are going to make the big difference at 6000+ (where you are typically in your passing zone)

You really have to trust your builder that your engine is a top notch, middle of the road, or back marker. The good thing about FV racing is that a good driver can finish up front in most any decently prepared engine. (Whether 56HP or 65HP )

[hardingfv32-1]

Peak power at 5100, is this correct? I have always thought it was closer to 5800.

Brian

[grimes34]

"The good thing about FV racing is that a good driver can finish up front in most any decently prepared engine. (Whether 56HP or 65HP"

Not in my neighborhood ! If you got a 52hp motor and the other guys got a 57hp motor, You finish last!

[SR Racing]

Most all hit peak by 5100/5200 RPM. A good one will hold it out to 5500 or maybe 5550, but they are all dropping by then. I suspect we will see some large cam retard engines for the run-offs. (at RA) They might hold power slightly past 5550. Up in the air yet is how well they go up the hill on the front straight. Since torque might be down a bit at 5000. But as long as you are in a draft, you will be there for the pass at 6500 RPM. I will have to look at some DA graphs to see where it will be optimized. We haven't done a FV race at RA in several years.

[SR Racing]

Not in my neighborhood ! If you got a 52hp motor and the other guys got a 57hp motor, You finish last!

I was joking about the 56HP vs 65HP.. However, a 52HP motor is a broken motor,... In spite of that, if you give 52HP to any of the top drivers in FV they will still finish near the front. I have seen it happen many times. I have also seen some of the biggest motors ever dyno'ed finish in the back... <g>) That's one of the things that make FV a great driver's class. To win the run-offs (especially at RA), you need a good engine, but the best drivers will still finish up front.

[wroché29]

Hi-jacking the thread: A while back there was a discussion about adjustable cam timing and how it wouldn't be an advantage to have track-specific engines with regeards to cam timing. Now I'm reading that RA engines would benefit from retarded cam timing.
Can I assume that the previous discussions were an effort to vote down the proposed change? It's a rhetorical question, but if you can't resist then go ahead and jump all over me anyway...

[Ed Womer]

It sure would be a good idea to be able to adjust the timing without having to tear the engine apart. Weither it is practical or not it would save alot of expense.

Ed

[wroché29]

Sorry Colin;

I THINK I'm at 56 horsepower, can't convey the area under the curve though... Other things to consider are HP losses through the drive train, rotating mass, etc.

[brian]

Although I have seen peak numbers above 5100, I agree with everything that JIm has said.

Since I was a more vocal participant against the cam gear change I will say my objection was more about tradition over technical issues. If a race course contains long straightaways, the rpm will be higher. That being said, more retard will shift the hp up the curve. A move from Heartland to RA is a perfect example. Heartland was a challenge because rpm was held to the lower ranges and RA will be just the opposite. There will be more changes than cam timing. Head modifications, ring packages, even valve springs may change so look for a lot of development this year. Of course trannies will be the first major thing changed.

I apologize for the shameless plug, but at BRM Engineering, one of the few suppliers that prepare both engines and trannies, we've had success at both kinds of tracks including the 2008 Sprints win. Give us a call.

[hardingfv32-1]

I reviewed my records and my dyno work shows 5800 as max HP point. This is with 4-5 deg cam retard. Two different tachs, one mechanical and one electronic. After bring the oil up to temp, I start my dyno pulls at 4000 and go to 6500. Head temps start at 300 deg and climb to 350. After the dyno pull, I let the heads cool to 300 degs and repeat. My cooling system cannot keep up with the head temp gain.

All that being said, comparing my engines to other top national competitors, my engines DO NOT show any top end advantage. What could be the reason for the deference in top end rpms...5100-5200 vs. 5800? These circumstances encompass the use of three engines and three gear boxes.

Brian

[SR Racing]

Brian (BRM) is right (again)...

Certainly the cam gear timing has an optimal setting at each track. My objection to the adjustable cam gear was simply that changing timing with an adjustable gear is not that simple. You have to remove the engine, oil pump and cover, possibly some lines, and then go in the case to adjust the gear/washers to get the timing you desire. Cam gear bolts are a common thing to break/loosen, and when they do they can do lots of engine damage. So I was opposed. The vast majority of guys use a 3-4 deg retard, which is pretty acceptable for most all tracks. However the more time you spend at high RPM the more that the additional retard can help. There isn't any free lunches though. You loose a little bit on the low end.

In this vein.. We use a Cam Timing wheel at assembly and cam doctor cam checker. The cams and gears can be off a couple degrees from the factory. So, just blindly adding retard may hurt, unless you know what your ACTUAL straight up timng is.

[SR Racing]

What could be the reason for the deference in top end rpms...5100-5200 vs. 5800? These circumstances encompass the use of three engines and three gear boxes.
Brian

Brian,

I suspect a 5 deg key might get you HP up closer to 5800, but that would really be the max.... I am looking at several runs right now (3 and 4 deg motors). They all peak closer to 5200. These runs are from the chassis dyno. We typically use 3rd gear runs since the inertial mass is 2200 lbs, so that represents a more real world acceleration rate. These are just about exactly the same as we see on the Engine dynos. (They of course are without the trans.) If your peak is 5800 and it is still within a HP or so of 5200, I sure wouldn't worry about it.

Also, I assume you are using a water brake. What acceleration rate are you using during the run. Typical is about 300 RPM / sec on a water brake dyno. On the Chassis dyno it's about 150 or so per sec. (In the 5500+ RPM range) Anything faster than 300 RPM / sec and your inertial effects of the engine are going to be pretty significant and will make different numbers.

While a servo throttle and water brake control on the dyno is pretty expensive, it does eliminate the inertia effects and make for better repeatabilty.

[G.B.]

Sorry if this is a naive question, but are the quoted HP figures measured at the wheel or the flywheel?

[hardingfv32-1]

If you review this thread you will notice that there have been few HP quotes. What would be the point. It is a useless number because you have no idea how it was derived. That being the case, no engine builder wants to volunteer his numbers when his competition could be inflating his. Makes for a lot of customer noise. All that matters to an engine builder are the numbers he gets from his test procedures for his own internal use.

Most engine builders use an engine dyno to get flywheel HP. These Vee engine dyno installations for the most part are primitive. SR racing is one of the exceptions. They also have a chassis dyno.

Engine HP is one area that takes time and money to acquire. Pretty much the normal racing issue.


Brian

[SR Racing]

Sorry if this is a naive question, but are the quoted HP figures measured at the wheel or the flywheel?

Brian is correct. However, for the the peak HP numbers discussed here were flywheel. The rear wheel HP is about 6 HP less than flywheel at the peak HP point. (This can vary with wheel mass.)

[Fos]

Well, two important questions.

1) Can Santa bring 'more' HP?

2) Does HP really refer to 'Higher Power'? I used to equate engine builders with religion.

If Bill can remember, I can't tell anything about HP, more or less. He beat me with my own engine a long time ago.

Bill, I really dig your avitar... it's very distracting! Who, where, what?

Happy Holidays everyone! May you and yours get all the HP you need!

TTFN
Fos