WAWA wrote:you mean it's not to finish the great "which is better, Carb's or F.I dedate"
I wish. I wanted a free dyno session.
Let's face it, I'm sure everything is going to be important, but the faster it accelerates from one RPM to the next at any given load has to show the final results of the usable power within the desired operating range. Fuel consumption would be an issue on a cup car. Individual cylinder combustion pressure, temperature, A/F ratio, would allow one the data to maximize overall output. All downhill from there. Maybe valvetrain dynamics under actual operating loads/RPM's?
Mark Whitener
www.racingfuelsystems.com
____
Good work isn't cheap and cheap work can't be good.
Does the engine in question race 99% of the time in gear or does it use gear changes?
If so the transitional response/Recovery response would be the 2nd variable after acceleraion time from RPM a to b.
Bret
[img]http://photos-g.ak.fbcdn.net/hphotos-ak-snc1/hs139.snc1/5928_111214857139_110806152139_2127222_6826389_n.jpg[/img]
[i]Those of you who think you know it all are particularly annoying to those of us who do[/i]- Penske garage sign @ Indy circa '71
SStrokerAce wrote:Does the engine in question race 99% of the time in gear or does it use gear changes?
If so the transitional response/Recovery response would be the 2nd variable after acceleraion time from RPM a to b.
Bret
Bret:
The engines for this test are in high gear most of the time; although the point you bring up is very important.
Excelleration is in the design-process of equipping one of the dyno's with a transmission, which will allow for analysis of this response/recovery that you speak of. As you know, there is a lot going with the engine at the rapid transition during and immediately following an upshift and providing the ability with the engine at WOT is highly anticipated. The transmission option will not be in effect for the test session next week.
The dyno John uses to test is also a little out of the ordinary to the extent they have modified it so that the engine drives through a 4 speed Lenco to simulate, as closely as possible, a car making a pass down the strip.
This dyno test session was finally run yesterday and I can report in more detail than previously considered.
Engine: Dodge R5-P7 Cup Engine w/restrictor plate.
Test: Durability & acceleration using trace chart of 1 lap @ 2.5 mile Daytona Speedway.
RPM range: 8200-8500 at WOT. Variance due to cornering resistance. Occasionally accelerated to 8900 RPM for simulated higher speed drafting periods.
Range: 700 miles total. 1st run = 80 miles, stopped for valve lash check. 2nd run = 60 miles, stopped for visual inspection of engine & dyno. 3rd run = 560 miles non-stop @ WOT.
Duration of 560 mile continuous test: Approx: 4 hours.
The engine & dyno were automatically controlled throughout the test session.
Sounds like a fun test. Did you guys use a pressurized radiator setup, or a standard dyno heat exchanger?
Doug
Hi Doug:
A pressurized heat exchanger was used.
More interesting data:
The 560 mile nonstop segment consisted of cycling the restrictor plate engine through the rpm span that the engine will experience in the Daytona 500. There were no simulated pit stops made. This portion of the test took 186 minutes to complete.
The crankshaft made 1,562,400 revolutions in the 186 minutes.
MadBill wrote:8,400 RPM average! I had no idea plate engines ran that high!
Yep. Part of the COT-deal. Bigger hole in the plate. At Talladega last year they were seeing 8,900 at certain times. (New tires, lined up & catching a 2-wide group...) 8,800 @ Daytona during testing last month too.
This team failed a 500 mile durability test less than a month ago at a facility in Detroit. Working 7 days @ week since that test; the team worked out a combination they hoped would last for 500 miles and still have good power. They succeeded.
Once they realized the engine was sound (and while the durability test was underway), they studied:
5) Acceleration from 8200-8500, and from 8200-8900 RPM's.
6) Fuel Flow
7) Air Flow
