The BritishV8 Pub

Sure would be nice to see the results of those dyno runs from the 2009 Meet!

Maybe Max has them.

Tony,
While we're waiting for the results, here's a video of one of the participants:
[www.youtube.com]

"DynoBeast",

Have your specs changed from the 2007 dyno (255hp/301tq)? She is a beauty (the car Ken :)) and I'll say it again - those wheels you switched to were the icing on the cake!

Hi Tony,

You know they say a dyno test results should only be used as a tool and not bragging rights since the numbers can vary and looking at the two charts for this car, I believe that to be true.

The first test on a Dynojet unit using a "standard" correction factor. I spoke with the shop this morning and they used to do a print out using the standard CF and the "SAE J1349" CF. Now, for some reason, they just print out the results using standard, (suppose to give about an 8 HP increase). Chart:

So, now it's off to Carolina Auto Masters at the BV8 meet. I also spoke to them this morning. They're using a Dynojet unit appling the SAE J1349 CF. I expected a lower reading based on the fact that the standard CF displays a higher number. The guys at Carolina do alot of work on these LT1/LS1 engines and before they did a run, he had correctly predicted the HP and Torque results. They know their stuff. Chart:



So why was the SAE CF test higher than the Standard CF test? Beats me.

Tony, I had my TR6 at the V8 Meet but put a rod out the side of the block on the way down doing some drag racing. Anyway I was very disappointed not being able to take part in the dyno session. When I got home i put a new short block in the car and I was off to the dyno to see what it could have done at the meet. It did 400 HP and 400 ft lbs at the rear axle. Now I am even more disappointed that I was not able to make that run in front of my peers.

Dale! us V8 guys are tickled you did not make a Dyno pull. Would have been embarassing. We were not pleased that you had the engine problem. You have some very impressvie numbers and look fwd to seeing you at Indy. Really glad the head was not damaged.

THE head?!

Somtin' wrong with dat! ;)

Ken - vairdy inderestink......your hp is fairly close, but your torque was 20% higher (that's a lot lot) in Durham vs Toronto and on your second run in Durham it was 10%+ (that's a lot) lower than the first run - #'s higher overall ilo the higher o/s temp and humidity too.

Dale - yeah, I saw the grenade pics. Try to post results - would love to see the curves. Assume you were in fighting trim with 35 lbs of boost?

Anyone got a guestimate on what to add back-in for flywheel #'s on a Mustang dyno (much more expensive dyno than the dynojet type and supposedly more accurate)? I always assumed I had a stock rover 3.9 cam in mine - that panned out on the torque curve on a dyno run I had quite awhile ago - looked like a brazilian cliff diver @ 3000 rpms.

I don't have my curves in digital form and i am not sure how to post it here. Let me see what I can do. I was at 24 pounds of boost. 26 is about max for me since I only run pump gas.

Hey All:

I believe I gave the full list of dyno results to Curtis to post in the "overview" of the meet (with all the other "results", like karting, etc.)

First, Ken's runs: a) the "high" torque of the first run is the tire slip when he's first engaging. (The "premature peak".) These are usually ignored. b) Ken's computer isn't properly tweaked and you can see in both the Toronto and Durham runs that his mixture slowly tanks as the revs go up. This explains his curve "flattening out". Usually the torque and HP curves will cross at 5250 rpms and the HP will continue upwards. With the mixture dropping below 12 to 1 Ken is losing hp.... c) Yes, my dyno guy Jeff nailed it on the head. Asked if it was a stock LT1, then said "It'll do 270...." :-)

RE: driveline loss. Jeff says the modern cars are around 15%. Though we didn't get a chance to PROVE it (this is what Targett's racecar was going to be for. He has ENGINE dyno numbers and we would then have been able to compare with Chassis Dyno numbers. Alas, he broke his clutch at the Gold Cup!) we've found the "older" drivelines to lose more like 20%, and sometimes nearly 25%... It seems the lower the output, the more likely the loss is a higher percentage, probably due to overcoming inertia that is more dependent on number of gears, moving parts, etc., than what is actually thrusting down the shaft... :-)

M

Thanks Max for the update on the number's. Hopefully Curtis will have the next issue & info ready soon. The Drive line loss #'s are helpful and generally used for 15% to 18% as representative #'s for FWHP & Torque. Thanks again for a GREAT meet!

"Usually the torque and HP curves will cross at 5250 rpm"

Torque and HP curves will ALWAYS cross at 5250. HP will ALWAYS be higher than torque above this point, and will ALWAYS be lower below this point.

The dyno measures torque, and then calculate HP using this formula:

HP=torque*RPM/5250

RPM/5250 is less than 1 below 5250, more than 1 above 5250, and equal to 1 at 5250.

Just one of the reasons I consider HP to be a worthless number.

Now that's vairdy inderestink.

Hey Max - thanks for responding to pm and posting. You and Emily did a GREAT job.

After that afternoon of karting, I actually had to pass on the pizza and beer - I beat the @$%& out of myself -
all muscle and no finesse!


"He has ENGINE dyno numbers and we would then have been able to compare with Chassis Dyno numbers." - Uh, Robbie - is your engine out of your car while it's being painted ;>)

OK dyno guys, answer me this if you can. How much airflow does it take through the engine to produce 1 hp? (or 300, or 500) and what is the conversion to mass?

Jim

Thanks to Curtis here are my dyno results. As you can see it does not have much torque down low. Nothing like what Ken has.