Don Terrill’s Speed-Talk

Anyone up for a little fun?

Excelleration has a HUGE dyno test coming up later this week using one of their inertia engine dyno's. The name of the company that is bringing engine(s) and the series they race in is confidential; however it is OK for me to reveal the type of data that this company is most interested in analyzing.

I cannot reveal the actual numbers - only the type of data. ie: Torque, HP, RPM/Sec, fuel flow, bsfc, A/F, cylinder pressures, etc. It is this type of data that you should predict will be the most interesting to this company. Please provide your predictions before this Thursday, Jan. 10 @ 3PM. After the test has concluded; I will post the type of data in the order of importance to this company.

Here are a few details to help formulate your guesses.

Engine:

American made V8
Less than 500 C.I.
Single carburetor
Gasoline
Testing under 10,000 RPM

The winner gets to be called --- the winner!

Mike Laws wrote:Anyone up for a little fun?

Excelleration has a HUGE dyno test coming up later this week using one of their inertia engine dyno's. The name of the company that is bringing engine(s) and the series they race in is confidential; however it is OK for me to reveal the type of data that this company is most interested in analyzing.

I cannot reveal the actual numbers - only the type of data. ie: Torque, HP, RPM/Sec, fuel flow, bsfc, A/F, cylinder pressures, etc. It is this type of data that you should predict will be the most interesting to this company. Please provide your predictions before this Thursday, Jan. 10 @ 3PM. After the test has concluded; I will post the type of data in the order of importance to this company.

Here are a few details to help formulate your guesses.

Engine:

American made V8
Less than 500 C.I.
Single carburetor
Gasoline
Testing under 10,000 RPM

The winner gets to be called --- the winner!

Plate or open?

hi mike


id say ....fastest accelleration rate rpm/s

I'll bite, I say RPM/sec as well and BSFC second. Was that the same dyno my SB2 was going on for that carb/FI shootout?

PPH

I do not know what the company's agenda will be, so I am an interested party as well. Once I learned of the session - several test types came to mind, however I won't know what is used until after the session is completed. After the test is completed - I will post all of the types in the order of importance.

It's more than fine for everyone to predict one or more test topics.

Mark: Yes, it is the same dyno and I am still working on coordinating a carb/fi test.

RayJE Carburetors wrote:id say ....fastest accelleration rate rpm/s

I'm with you on that one.

I'm not really sure what the question is asking here though, seems to be worded oddly.

Bret

On an inertia dyno, time from X RPM/speed to Y RPM/speed IS power.

SStrokerAce wrote:

RayJE Carburetors wrote:id say ....fastest accelleration rate rpm/s

I'm with you on that one.

I'm not really sure what the question is asking here though, seems to be worded oddly.

Bret

Bret:

You're right - I did not do a good job of explaining this for some reason. Sorry about that! It is clear in my mind, but the delivery is poor. I'll try once more.

A company is going to dyno test at least one engine on a fairly-sophisticated inertia-style engine dyno this week. I have intimate knowledge of this dyno that simulates the operation of a racecar more closely than an absorber-style dyno is able; thus the data is different than that from an absorber style dyno.

This company has previously tested like engines on the most sophisticated and elaborate dyno's available. Those dyno's (and the inertia-dyno) offer multiple features to analyze. The list of features offered is nearly endless. From torque & power to individual cylinder pressures, to various flows, temp's etc...

There is a group of sharp individuals on this forum that enjoy learning about the latest technologies and also enjoy predicting outcomes.

When I learned of this upcoming test - my immediate thought was; "I wonder what types of data this company desires to analyze during the test-session, and what their priorities are". Upon realizing that this information was interesting to me - I thought it might be interesting to anyone on here, so I decided to offer it up as a quiz.

For example:

My guesses (in order of priority) would be:

1) Rates of Acceleration
2) Fuel Flow (during acceleration and deceleration)
3) Air Flow (during acceleration and deceleration)
4) Intake Vacuum
5) A/F Ratio
6) Individual A/F Ratios

I have the knowledge that all fluid temp's will be well-controlled and consistent; however if I did not have this knowledge - I would want to be able to see these temp's to ensure a consistent series of tests. These temp's would probably be at the top of my particular list.

Does this better explain the question?

I'll play.
I predict they are interested in:

1) Acceleration / deceleration - the change in RPM per degree of crankshaft rotation per (2) Torque load
3) Voltage at the plug for each spark occurrence
4) Exhaust flow
5) Exhaust temp
6) O2

Cylinder pressures

My highest priority would be time to accelerate from one given rpm to another. If it were a short-track engine say 5000-9500. If it was for longer tracks, say 6500-9500. This assumes the inertia load simulates the car running in top gear. Times should be very similar to on-track times if traction is not a problem.

If the engine were instrumented with pressure transducers in every combustion chamber as well as EGT, that data would be useful especially if the engine/dyno could be rolled and pitched to simulate on-track longitudinal and lateral acceleration. I'm looking to see if each cyclinder is making it's fair share of torque under simulated track conditions.

I would most definitely try to duplicate atmospheric conditions and liquid temps as seen on their race-shop dyno tests on that particular engine, but I suspect that is a given.

Jon

Rate of Accel.
Individual A/F ratio's
Exh. temps

Ron

OldSStroker wrote:My highest priority would be time to accelerate from one given rpm to another.

You mean like this:




To me that is THE best measure of performance, time from RPM to RPM under actual load.

My next priority would be A/F ratio for each cylinder.

Next would be exhaust temp for each cylinder.

you mean it's not to finish the great "which is better, Carb's or F.I dedate"