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dcb · 11-06-2009, 02:18 AM

As you said, if you had the money you would get lots more battery and motor and etc.

You don't. It's all about getting the most energy out of what you have, though I expect you will come back with "no it isn't" or somesuch oversimplification.

A couple questions (hint, there is only one answer)

Do you agree that you get the most energy out of a given amount of fuel at BSFC peak?

Do you agree that there is an optimal discharge rate for a battery to get the most energy out of it? (unfortunately lower is almost always better) and that you only have $200 of battery to work with currently?

Do you agree that you can typically approximate bsfc peak while accelerating a stick shift? i.e. hold 70% throttle and center shifts @ 3k in your case?

Do you agree that the load will typically be much less than %70 while cruising, and thus even though you are getting "great mpg", your engine is not extracting the most energy it can out of the fuel?

Still with me?

ok, so we have established:
1. Your engine DOESN'T need any help at being efficient during acceleration. (cus you know how to accelerate most efficiently)

2. Your engine DOES need help at cruise.

3. You have a fairly small amount of electric energy to contribute to your drive on the current budget. If you hope to see the most return at the pump (putting energy back in the car not via the wall outlet) you had better optimize.

So lets say you have 4 trolling batteries already, and they can make 3hp for an hour (just a swag), and your car needs 9hp at cruise, and you cruise for an hour daily. The effect would be like cutting your drag by a third.

Lets say you happen to be around the 3k rpm mark, the first problem you should notice is that reducing load increases bsfc. Well like with an aeromod, you will have to regear (get a trans out of a 1.3 or an xfi) to get your engine load back up to an efficient place (and fully realize your mpg going up by 50% maybe).

FYI, If you glide properly, the extra weight isn't a huge deal on acceleration, just takes you longer to glide to a stop.

11-06-2009, 02:18 AM	#178 (permalink)
dcb needs more cowbell Join Date: Feb 2008 Location: ÿ Posts: 5,038 pimp mobile - '81 suzuki gs 250 t 90 day: 96.29 mpg (US) schnitzel - '01 Volkswagen Golf TDI 90 day: 53.56 mpg (US) Thanks: 158 Thanked 269 Times in 212 Posts	As you said, if you had the money you would get lots more battery and motor and etc. You don't. It's all about getting the most energy out of what you have, though I expect you will come back with "no it isn't" or somesuch oversimplification. A couple questions (hint, there is only one answer) Do you agree that you get the most energy out of a given amount of fuel at BSFC peak? Do you agree that there is an optimal discharge rate for a battery to get the most energy out of it? (unfortunately lower is almost always better) and that you only have $200 of battery to work with currently? Do you agree that you can typically approximate bsfc peak while accelerating a stick shift? i.e. hold 70% throttle and center shifts @ 3k in your case? Do you agree that the load will typically be much less than %70 while cruising, and thus even though you are getting "great mpg", your engine is not extracting the most energy it can out of the fuel? Still with me? ok, so we have established: 1. Your engine DOESN'T need any help at being efficient during acceleration. (cus you know how to accelerate most efficiently) 2. Your engine DOES need help at cruise. 3. You have a fairly small amount of electric energy to contribute to your drive on the current budget. If you hope to see the most return at the pump (putting energy back in the car not via the wall outlet) you had better optimize. So lets say you have 4 trolling batteries already, and they can make 3hp for an hour (just a swag), and your car needs 9hp at cruise, and you cruise for an hour daily. The effect would be like cutting your drag by a third. Lets say you happen to be around the 3k rpm mark, the first problem you should notice is that reducing load increases bsfc. Well like with an aeromod, you will have to regear (get a trans out of a 1.3 or an xfi) to get your engine load back up to an efficient place (and fully realize your mpg going up by 50% maybe). FYI, If you glide properly, the extra weight isn't a huge deal on acceleration, just takes you longer to glide to a stop. __________________ WINDMILLS DO NOT WORK THAT WAY!!! Last edited by dcb; 11-06-2009 at 08:44 AM..