Don Terrill’s Speed-Talk

nitro2 wrote:

plovett wrote: I think average hp is what really matters when accelerating a vehicle.



paulie

It matters, but you can have two engines with the same average HP over the same rpm range and depending on the shape of the HP curve, one will accelerate the same car with the same gearing, quicker than the other.

I'm definitely with you there. But now we're going to have drag race these engines with optimized gearing........

plovett wrote:

nitro2 wrote:

plovett wrote: I think average hp is what really matters when accelerating a vehicle.



paulie

It matters, but you can have two engines with the same average HP over the same rpm range and depending on the shape of the HP curve, one will accelerate the same car with the same gearing, quicker than the other.

I'm definitely with you there. But now we're going to have drag race these engines with optimized gearing........

LOL. Could be done with the right dyno type AND the right formula to go with it.

nitro2 wrote:

plovett wrote:

nitro2 wrote:
It matters, but you can have two engines with the same average HP over the same rpm range and depending on the shape of the HP curve, one will accelerate the same car with the same gearing, quicker than the other.

I'm definitely with you there. But now we're going to have drag race these engines with optimized gearing........

LOL. Could be done with the right dyno type AND the right formula to go with it.

Okay, but might it depend on all sorts of other variables like the weight and drag, of the hypothetical vehicle the engine is going in? Just for starters? Also length of race (mph), traction, number of gears, etc. etc. etc.

I'm for the K.I.S.S. principle whenever possible.

JMO,

paulie

plovett wrote:

nitro2 wrote:

plovett wrote:
I'm definitely with you there. But now we're going to have drag race these engines with optimized gearing........

LOL. Could be done with the right dyno type AND the right formula to go with it.

Okay, but might it depend on all sorts of other variables like the weight and drag, of the hypothetical vehicle the engine is going in? Just for starters? Also length of race (mph), traction, number of gears, etc. etc. etc.

I'm for the K.I.S.S. principle whenever possible.

JMO,

paulie

Not really. You just want to race an engine, not a car.

nitro2 wrote:

plovett wrote:

nitro2 wrote:

LOL. Could be done with the right dyno type AND the right formula to go with it.

Okay, but might it depend on all sorts of other variables like the weight and drag, of the hypothetical vehicle the engine is going in? Just for starters? Also length of race (mph), traction, number of gears, etc. etc. etc.

I'm for the K.I.S.S. principle whenever possible.

JMO,

paulie

Not really. You just want to race an engine, not a car.

I think the point of the contest is to "race" engines.

plovett wrote:

nitro2 wrote:

plovett wrote:
Okay, but might it depend on all sorts of other variables like the weight and drag, of the hypothetical vehicle the engine is going in? Just for starters? Also length of race (mph), traction, number of gears, etc. etc. etc.

I'm for the K.I.S.S. principle whenever possible.

JMO,

paulie

Not really. You just want to race an engine, not a car.

I think the point of the contest is to "race" engines.

Well that may be the "intended point" of the contest, but I have yet to see any EMC or other contest where an engine was effectively "raced" against the others, and for that matter precious few dyno tests from anywhere, ever, that accomplished it either.

nitro2 wrote:

plovett wrote:

nitro2 wrote:

Not really. You just want to race an engine, not a car.

I think the point of the contest is to "race" engines.

Well that may be the "intended point" of the contest, but I have yet to see any EMC or other contest where an engine was effectively "raced" against the others, and for that matter precious few dyno tests from anywhere, ever, that accomplished it either.

Okay, well I guess you need to start your own contest where all the engines are dyno-ed, then put in the same car, with optimized gearing for each engine, and run down the track, hopefully under the same weather conditions and with identical track prep, and driven equally well. That would be cool.

plovett wrote:

nitro2 wrote:

Well that may be the "intended point" of the contest, but I have yet to see any EMC or other contest where an engine was effectively "raced" against the others, and for that matter precious few dyno tests from anywhere, ever, that accomplished it either.

Okay, well I guess you need to start your own contest where all the engines are dyno-ed, then put in the same car, with optimized gearing for each engine, and run down the track, hopefully under the same weather conditions and with identical track prep, and driven equally well. That would be cool.

Pretty much the same thing can be accomplished with an engine inertia dynomometer .. they can even simulate shifting gears and RPM drop.

Most are electric and around half a million dollars.

Walter R. Malik wrote:

plovett wrote:

nitro2 wrote:

Well that may be the "intended point" of the contest, but I have yet to see any EMC or other contest where an engine was effectively "raced" against the others, and for that matter precious few dyno tests from anywhere, ever, that accomplished it either.

Okay, well I guess you need to start your own contest where all the engines are dyno-ed, then put in the same car, with optimized gearing for each engine, and run down the track, hopefully under the same weather conditions and with identical track prep, and driven equally well. That would be cool.

Pretty much the same thing can be accomplished with an engine inertia dynomometer .. they can even simulate shifting gears and RPM drop.

Most are electric and half a million dollars.

Sounds good to me. It would be interesting for sure.

For the sake of progress and development, I think there should be two classes; NA and forced induction.

The competition would be to see who could develop the highest BMEP. Period. That would normalize
for size. A secondary option would be BMEP divided by rpm.

plovett wrote:

nitro2 wrote:

plovett wrote:
I think the point of the contest is to "race" engines.

Well that may be the "intended point" of the contest, but I have yet to see any EMC or other contest where an engine was effectively "raced" against the others, and for that matter precious few dyno tests from anywhere, ever, that accomplished it either.

Okay, well I guess you need to start your own contest where all the engines are dyno-ed, then put in the same car, with optimized gearing for each engine, and run down the track, hopefully under the same weather conditions and with identical track prep, and driven equally well. That would be cool.

LOL. What happened to the KISS principle.

Yeah an inertia dynamometer is needed, then it needs to be run the right way.

nitro2 wrote:

plovett wrote:

nitro2 wrote:

Well that may be the "intended point" of the contest, but I have yet to see any EMC or other contest where an engine was effectively "raced" against the others, and for that matter precious few dyno tests from anywhere, ever, that accomplished it either.

Okay, well I guess you need to start your own contest where all the engines are dyno-ed, then put in the same car, with optimized gearing for each engine, and run down the track, hopefully under the same weather conditions and with identical track prep, and driven equally well. That would be cool.

LOL. What happened to the KISS principle.

Yeah an inertia dynamometer is needed, then it needs to be run the right way.

These are your ideas, not mine. I was just trying to be nice.

I like just averaging hp over the specified rpm range. Simple and useful.

An inertia dynamometer with the right measurement parameter, is a lot better test than a regular dyno sweep test, and every bit as simple (assuming performed without gear changes and all that sort of thing). It's just not cheap.

That being said, one could also take a regular dyno sweep test and determine which engine would win on an inertia dyno roll on test, still keeping with the KISS principle. Just a formula, and all these contests use formulas of one sort or another to determine the winner.

Average HP is fine if there is a significant difference in average HP between 2 engines, but it's just not a good way to evaluate 2 engines that have pretty close to the same average HP.

What could we learn if each engine had in-cylinder pressure equipment? That would be cool alongside the dyno sheets.

Doing a standard xxx RPM dyno test has the engine see a variable load during the dyno test.

The inertia dyno will have a fixed load on the engine and show a variable RPM acceleration. The highest RPM acceleration rate will be around peak torque.

Stan