44+HP vs BMEP?

John Clasen · Joined: 04 Aug 2001 Posts: 563 Location: San Marcos, CA

Brant, I think you give the big guys more credit than they deserve. What they have that the individual builders do not have is numbers. Large numbers of people to throw at a problem (or a solution) and large numbers of dollars to support all those white coats. That enables them to try countless different pipe, ignition, cylinder and head combinations. The time necessary to perform that work alone kills most of the small guys, let alone the money. By the time we can test three or four combinations thoroughly, a week is past. The factory guys put a team on a project and the work is accomplished in one day. We have dynos, they have dynos; we have flow benches, they have flow benches; they have design software and so do we. It is remarkable to me that we can achieve the levels of torque and HP that we do out of these MX engines given the lack of resources. I am just saying that 42 to 44 Hp are realistic numbers from a MX'er, 48 & 49 are not (given todays rules).
One final point, your analogy about Katech & Loyning competing against Toyota or Cosworth or Honda (et.al.) is hardly what your typical kart engine builder is up against. We are not engineering and building an entire engine here, we are merely modifying its' characteristics to better fit our needs. It's not alot deeper than that.
Cheers, J.R,

[ August 08, 2001: Message edited by: John R. Clasen ]

John Denman · Posted: Fri Aug 10, 2001 2:03 pm Post subject: 44+HP vs BMEP?

Dynos are a funny thing. I don't think you can drop by your local National Bureau of Standards and pick up a Dyno calibrater.

I think is was Dynojet, but not sure, that offered a software upgrade some years ago from DOS to Windows. Magically I was told, the motors gained 3 HP when you upgraded.

A dyno is merely a reference tool. Put two identical dynos in the same room, and run the same motor on each under the exact same conditions, and they may read the same numbers. But take two different brands at random from any two shops, and they will almost certainly read differently.

Use HP as a reference. Did the last dyno run produce more or less power when those ports were reshaped? How much? The next thing you know, a customer is told, "yeah, I found another 2 HP and now you have 43 HP", but they don't say "according to my dyno that is probably not precisely calibrated". As long as it got 2 more HP then the builder did well (very well, tip him or her!)

Which motor is the fastest? Thats what they build tracks for. How much total HP on a dyno? Thats marketing.

Rodney Ebersole · Posted: Sun Aug 12, 2001 6:02 am Post subject: 44+HP vs BMEP?

Brant, Thanks for the list of Blairs works. but could you or somebody type in a clickable link in here so us lazy computor illiterate can find it.

Terry Tilton · Joined: 20 Jul 2001 Posts: 58 Location: Austin, Tx

If you had a 1000 ft straight, two karts of equal gearing, weight, driver ability, etc. How much if any would a kart that had a one or two horsepower advantage pull away from the other kart. I just find it hard to believe that one lousy but very expensive horsepower is going to amount to much if anything on the track. Can someone explain that to me?

John Neilson · Posted: Sun Aug 12, 2001 7:00 pm Post subject: 44+HP vs BMEP?

Terry,
To skip the HP formula conversion, think about this. Aerodynamic drag, an old saying was "to double your speed requires 4 times more HP.)
One step further, or back. My son and I did a test with the Stallion nose and a CIK nose on a kart. At 500ft, the stallion nose had a 2 mph advantage over the CIK nose. I smell FREE hp.

John

Drew Cleaver · Posted: Mon Aug 13, 2001 10:05 pm Post subject: 44+HP vs BMEP?

quote:
Originally posted by John Neilson:
Terry,
To skip the HP formula conversion, think about this. Aerodynamic drag, an old saying was "to double your speed requires 4 times more HP.)
One step further, or back. My son and I did a test with the Stallion nose and a CIK nose on a kart. At 500ft, the stallion nose had a 2 mph advantage over the CIK nose. I smell FREE hp.

John

Is there a pic of this nose somewhere???

Thanks,
Drew Cleaver www.vmaxracing.cjb.net

John Denman · Posted: Fri Aug 24, 2001 3:36 pm Post subject: 44+HP vs BMEP?

quote:
Originally posted by Terry Tilton:
If you had a 1000 ft straight, two karts of equal gearing, weight, driver ability, etc. How much if any would a kart that had a one or two horsepower advantage pull away from the other kart. I just find it hard to believe that one lousy but very expensive horsepower is going to amount to much if anything on the track. Can someone explain that to me?

Also depends on the exit speed into the straight. As far as from a standing start, I would say between 3-5 kartlengths on 1000 feet for difference between 39HP and 40HP. Less if the slower kart drops into the leaders draft.