wait4me

iTrader: (10)

I just went out and tried some settings. Here is what you need to do OP,

Go to table b1829 and from 6000-4000 rpm Put in -64 for the values in the gears you want it to pull down fast.
That is a NEGITIVE 64. "-64"

Then on the coast down table pull 15 deg from the table at the higher rpms. B5122.

That allowed my heavy car come down very fast.

ramey

Thanks very much!

As far as inertia goes, it is very significant, which is why i am doing a light flywheel. But the vacuum is largely constant with cid. The inertia is not just the flywheel. It is all rotating accessories if the car is not in gear. In an lsx that is probably 150-200lbs depending on what flywheel and crank you run, though the flywheel is the largest diameter. In your top fuel example, it is the entire weight of the car at 300 mph. Of course it will keep spinning.

edcmat-l1

iTrader: (10)

Yes, in my TF example, it is the entire drivetrain spinning the engine, which is a good example of what happens when you try and engine brake a car.

As for the inertia from the accessories, it is largely insignificant. Because it doesn't carry the weight of the flywheel, and it's not hanging off the end of the crank. The whole purpose of a flywheel is inertia. Ever try to start a lawnmower without a flywheel or blade? The whole purpose of a flywheel is inertia.

http://en.wikipedia.org/wiki/Flywheel

ramey

The only difference between any mass connected to the drivetrain with respect to inertia is the moi, largely dictated by diameter of the weight. Ac, alternator, crank, valves, driveshaft etc are all part of the total moi equation with the flywheel. Thus taking 20lbs off the fw may only be 10% of the total mass though probably more % of moi due to diameter.

edcmat-l1

iTrader: (10)

The flywheel has all the Mass. None of the other stuff mentioned stores any energy. It doesn't have enough mass. Not even combined. Valves move back and forth. No inertia. Driveshaft, driveline, that has significant weight and can store a signficant amount of energy. An AC pulley has hardly any weight. Same with an alternator. A balancer has some, but not much, and it's concentrated too close to the centerline of the crank.

Perfect example, unbolt a torque converter and start and rev an engine and see how fast it accelerates and decelerates.

ramey

Thats great info. I dont think we were brave enough to try a negative. I'll try that. Thx.

wait4me

iTrader: (10)

I went thru the assembly last night that I had done in idapro originally when mapping out the tables/calls for this controller type, and it looks to be that a negative number in the table will call for a negative torque request. If it is 0 or higher it calls for a positive torque request. Hence when at idle and you need more airflow, you add to that table and it adds it. A value of 0 would be free rev it looks like with no throttle help. Neg will pull it down via throttle blade.

ramey

well, the 23 lb clutch/pp/flywheel assy is in, down from 57, and without any tuning, it does rev up a bit quicker, but certainly does not drop throttle any quicker. which ends the inertia v. throttle position tuning debate. i will try some negative values as wait4me posted and let you guys know what happens.

now, with the GS transmission and light flywheel assy, getting the power down in 1st and second gear coming off corners is the big issue. I assume you can tune throttle OPENING rate v. pedal position pretty easily. I will do a search, but any info is helpful.

HeavyMetl

iTrader: (2)

Has nobody here driven and old school carbed hot rod? Even with a heavy flywheels, rotating assembly, and driveline parts the engine deceleration when closing the throttle is dang near instant. The goofy LS electronic controls has long been a complaint of mine too during engine deceleration.