Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 09-07-2011, 07:45 AM   #41 (permalink)
Corporate imperialist
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,175

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)

Snow flake - '11 Nissan Leaf SL
SUV
90 day: 141.63 mpg (US)
Thanks: 269
Thanked 3,522 Times in 2,796 Posts
Back when the I had converted to electric fans it could barely hold the load at idle with the head lights and the big fan on. When I would apply the brake the volts would always drop.

I will try the 95 amp alt first. Spinning the standard alternator faster will likely just burn it out sooner and still not provide the amps I need. I have nearly doubled the power needed at idle with the electric fuel pump (5amps) and electric coolant pump (6amps).
When the fans (3 of them) need to run theres 12+5+5 more amps right there. 99% of the time I can get away with just running the larger 12 amp fan.
At night turning on the head lights and running lights is about another 12 and the brake lights draw 4 or 5 more as needed.

I plan on building a glassless solar panel that puts out 18.5v (open circuit) that should be good for pushing about 6 amps into the electrical system at 14.5 volts. If it works well I might build a second one.
And I will install my 21v @ 0.4 amps salvaged panels to apply power to the batteries all the time when the sun is out (no danger of over charging, it takes nearly an amp to hold voltage at 13.2v and 2 amps to maintain 14.5v).

__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 09-07-2011, 09:39 AM   #42 (permalink)
Master EcoModder
 
Diesel_Dave's Avatar
 
Join Date: May 2011
Location: Indiana
Posts: 1,194

White Whale - '07 Dodge Ram 2500 ST Quad Cab 2wd, short bed
Team Cummins
90 day: 37.68 mpg (US)
Thanks: 112
Thanked 511 Times in 213 Posts
Quote:
Originally Posted by slowmover View Post
Then how do we use it? I haven't read up on how others interpret these maps since we didn't have one. I much appreciate your pointing out this map.
Okay, you probably already know some of this stuff, but I'll start off with the basics (because that's what I always do to myself when I'm trying to figure something out).

The first thing to consider is the required power output of the engine. This is determined by:
1) Total vehicle & payload weight
2) Road grade
3) Aero drag
4) Rolling resistance of the tires
5) Mechanical efficiency of the drive train
6) Desired acceleration

For our purposes we can consider the first 5 things as givens--so we have a certain vehicle with a certain weight on a certain road. When you're driving the only thing you really have control over is your desired acceleration. Once you decide that, you know the required horsepower.

Now, look at that BSFC map I reffered to earlier (Post #37 in that other thread). There are 3 dashed orange lines. Each of those lines represents a different horsepower level. Up and to the right is the highest power level. So those 6 above factors dictacte which of those lines you will be on.

Now, even though you now know which line your on, there are various conbinations of engine speed/torque that can generate that horsepower (anywhere along the line). This is because horsepower = speed (rpm) x torque (lb-ft) / 5252. So you can see that 1000 rpm/ 200 lb-ft gives the same horsepower as 2000 rpm/ 100 lb-ft (38 hp).

Now, gearing will determine where you are on the line, because gearing determines the engine speed. The speed of your axle is dictated by your vehicle speed (and tire size) & gearing determines your drive ratio (between the engine crank and the axle). Thus, gearing determines the engine speed. For example, if the total drive ratio is 2:1 then your engine speed = twice axle speed).

So, going back to the chart. Let's say you have a 6-speed transmission. In theory, you have 6 different places you can be on that line. Your highest gear will put you the furthest to the left, the lowest gear furthest to the right. In practice you don't have 6 choices because some of the gears would put you completely off the map. If you picked your lowest gear at 70 mph, you engine might have to turn 15,000 rpm to generate enough power (which, obviously, the engine can't actually do). If you picked your highest gear a 10 mph, your engine might have to produce 1500 lb-ft of torque (which it can't do either). So realistically, in any given scenario, you probably only have 2 or 3 choices.

So, look at the BSFC map again. If you're at any given power requirement (any orange line), would you rather be down and to the right or up and to the left? You can see that, for this type of map, in almost every case, a lower rpm will give you better BSFC. (Note: if you look at a BSFC map for most gas engines, you'll see that this isn't true nearly as much for them).

So...all that leads me to my rule of thumb: unless you're getting up close to the torque curve (close to not being able to produce the required power), keep your rpms as low as possible.
__________________
Diesel Dave

My version of energy storage is called "momentum".
My version of regenerative braking is called "bump starting".

1 Year Avg (Every Mile Traveled) = 47.8 mpg

BEST TANK: 2,009.6 mi on 35 gal (57.42 mpg): http://ecomodder.com/forum/showthrea...5-a-26259.html


  Reply With Quote
The Following 2 Users Say Thank You to Diesel_Dave For This Useful Post:
DieselFan (09-07-2011), slowmover (09-07-2011)
Old 09-09-2011, 08:44 PM   #43 (permalink)
Banned
 
Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,442

2004 CTD - '04 DODGE RAM 2500 SLT
Team Cummins
90 day: 19.36 mpg (US)
Thanks: 1,422
Thanked 737 Times in 557 Posts
One thing I find surprising in Gear Vendor instructions is that oil needs to be changed every 5000 miles!

See this thread -- and links in Post #13 -- for one mans' solution to this.

My Gear Vendor's Experience.

And here's a thought experiment with merit:

Reversing an NP-205 in a Re-Gearing Strategy

by a man I believe has also been a member here (but not recently).


Now, from the referenced post #37, the "generic TD map":






I'll print this up to keep in the truck -- and the explanation -- and change my habits. Tried to keep it simple (which worked well), so, as a few years have gone by having moved from 18+ around town to 20 for calendar year intervals (where highway miles are set aside); I'll see if I can't get that next one or two mpg on a regular basis.

Was reading around today and came across a pretty decent conversation (okay, it's Ford, but you'll get used to the odor after awhile). Big Dave shows up on plenty of these Ford FE "conversations", no surprise:

FTE: What is the 7.3 Sweet Spot?

And some other Ford TD interest:

Single Post: BSFC Map Value Loading


.

Last edited by slowmover; 09-09-2011 at 09:30 PM..
  Reply With Quote
Old 09-10-2011, 11:04 PM   #44 (permalink)
Master EcoModder
 
Big Dave's Avatar
 
Join Date: Jan 2008
Location: Steppes of Central Indiana
Posts: 1,319

The Red Baron - '00 Ford F-350 XLT
90 day: 27.99 mpg (US)

Impala Phase Zero - '96 Chevrolet Impala SS
90 day: 21.03 mpg (US)
Thanks: 0
Thanked 186 Times in 127 Posts
I'm surprised the guywith the Cummins was lugging at 1600 RPM.

Mine engine runs nicely at 1320 RPM & 70 MPH.
__________________
2000 Ford F-350 SC 4x2 6 Speed Manual
4" Slam
3.08:1 gears and Gear Vendor Overdrive
Rubber Conveyor Belt Air Dam
  Reply With Quote
Old 09-10-2011, 11:11 PM   #45 (permalink)
Banned
 
Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,442

2004 CTD - '04 DODGE RAM 2500 SLT
Team Cummins
90 day: 19.36 mpg (US)
Thanks: 1,422
Thanked 737 Times in 557 Posts
It helps to have a definition of "lugging". Have we done that here?
  Reply With Quote
Old 09-10-2011, 11:14 PM   #46 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,762

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,585
Thanked 3,555 Times in 2,218 Posts
I want to know the fe at 105 mph, cuz I never cruise at less than that.
__________________


  Reply With Quote
Old 09-10-2011, 11:25 PM   #47 (permalink)
Banned
 
Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,442

2004 CTD - '04 DODGE RAM 2500 SLT
Team Cummins
90 day: 19.36 mpg (US)
Thanks: 1,422
Thanked 737 Times in 557 Posts
Quote:
Originally Posted by Frank Lee View Post
I want to know the fe at 105 mph, cuz I never cruise at less than that.
What tahr size you runnin' to give that speedo readin' around town?
  Reply With Quote
Old 09-12-2011, 11:42 AM   #48 (permalink)
Master EcoModder
 
Diesel_Dave's Avatar
 
Join Date: May 2011
Location: Indiana
Posts: 1,194

White Whale - '07 Dodge Ram 2500 ST Quad Cab 2wd, short bed
Team Cummins
90 day: 37.68 mpg (US)
Thanks: 112
Thanked 511 Times in 213 Posts
Quote:
Originally Posted by Big Dave View Post
I'm surprised the guywith the Cummins was lugging at 1600 RPM.

Mine engine runs nicely at 1320 RPM & 70 MPH.
What Cummins guy said he was lugging at 1600 rpm? If you were referring to me, I said I rarely run over 1600 rpm.

And I envy the capability to run at 1320 rpm @ 70 MPH

__________________
Diesel Dave

My version of energy storage is called "momentum".
My version of regenerative braking is called "bump starting".

1 Year Avg (Every Mile Traveled) = 47.8 mpg

BEST TANK: 2,009.6 mi on 35 gal (57.42 mpg): http://ecomodder.com/forum/showthrea...5-a-26259.html



Last edited by Diesel_Dave; 11-03-2011 at 01:19 PM..
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Report: Improving the Aero Characteristics of a Dodge Ram Pickup Truck MetroMPG Aerodynamics 36 08-05-2013 11:25 PM
SAE report: Pickup Truck tailgate aerodynamics... better up, down, or off? MetroMPG Aerodynamics 5 11-17-2011 02:35 PM
Aeromoding my truck ('95 Chevy S10 pickup) bennelson Aerodynamics 42 12-17-2010 06:28 PM
Video: Homebuilt Hybrid Pickup truck bennelson Hybrids 18 11-26-2008 04:48 PM
More Pickup truck Aero bennelson Aerodynamics 16 05-13-2008 09:32 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com