[Gmecm] GMECM Question related to fuel economy

[BNRVL at aol.com]

Rick..I drove my 1033 Dodge Monday and what Torque the TPI system has   
!!WEOW...!!  will add r-700 later for lock-up OD feature ..
 
Bob
 
 
In a message dated 3/2/2010 7:41:11 P.M. Central Standard Time,  
wades at mountainmanmotors.com writes:

As an  old school "do it myself" (with a few exceptions) kinda guy, I can 
say
that  I would prefer that big old engine with all its cubes, friction,
weight,  etc. vs. a  smaller engine anytime.  As far as economy, the  big
engine gets the nod - I like the torque thing - lots of torque at a low  
rpm.
Fuel injection just adds icing to the cake.  It's like a nice  carrot cake
with thick icing and then adding another layer.  Just gets  better.



-----Original Message-----
From:  gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On 
Behalf
Of  clare
Sent: Tuesday, March 02, 2010 5:56 PM
To: 'A list for discussing  General Motors EFI'
Subject: Re: [Gmecm] GMECM Question related to fuel  economy

What it comes down to is displacement per minute.
A small  engine wound tight pumps the same amount of air as a large engine 
at
low  speeds.(or can, depending on displacement and speed)
The big engine has  throttling losses and increased friction due to shear
size, but the little  engine has increased friction from higher surface
speeds. They tend to  balance out somewhat.
What you really want for economy is an engine that  produces adequate power
at it's maximum torque rpm with high manifold  pressure. - In other words -
an engine that runs at maximum efficiency at  cruise.


> -----Original Message-----
> From:  gmecm-bounces at diy-efi.org 
> [mailto:gmecm-bounces at diy-efi.org] On  Behalf Of Rick McLeod
> Sent: Tuesday, March 02, 2010 8:59 AM
>  To: A list for discussing General Motors EFI
> Subject: Re: [Gmecm]  GMECM Question related to fuel economy
> 
> Slight disagreement in  terms, cruise is more of a toruqe 
> thing, not horespower thing. Torque  keeps things in motion, 
> horespower is really delta of motion.
>  
> Matching the build of the engine torque curve to the desired 
>  application is key to mileage.
> 
> My experiences:
> I  targeted a '87 Camaro build using a 5.7 at a 2400 to 3000 
>  torque peak, and geared to cruise 70 MPH at the lower end of 
> the  curve. Result, at 75 MPH it turned right at 2500 and 
> knocked down  over 30MPG through rolling interstate thru 
> central Missouri,  so it can be done. My '86 vette does even 
> better, due in part to  being lighter weight. Don't believe 
> you must have tiny engines to  bang big mileage, torque is 
> your partner, along w/ a smart tune  in the ecm.
> 
> So, I'd go for a bigger small engine, something  that is 
> designed or rebuilt to develop low end torque - you may need  
> to design intakes for that, which is what the TPI maximizes 
>  w/ it's long runner design. And, a good lockup converter goes 
> a long  way to mileage, but consider a higher stall to allow 
> it to build  torque RPM on launch (a relative term) to 
> maximize stoplight  mileage.
> Most of the advantage is gained from getting the most from a  
> load of fuel, and not doing it as frequently (think about 
>  diesels) so the more torque at least RPM and then gearing is 
> really  where a mileage monger is happy. Goes to the less 
> frictin at lower  RPM as well, the less strokes per minute is 
> less friciton actions per  minute, friction doesn't increase 
> w/ RPM, but double the RPM and you  double the friction events 
> thereby doubling the required effort to  overcome friction per minute. 
> 
> cheers
>  -rick  
> 
> 
> 
> 
>  ________________________________
> From: Scot Sealander  <ssealander at stny.rr.com>
> To: A list for discussing General  Motors EFI <gmecm at diy-efi.org>
> Sent: Mon, March 1, 2010 7:27:46  PM
> Subject: Re: [Gmecm] GMECM Question related to fuel economy
>  
> 
> That being said, a constant cruise requires a certain amount  
> of horsepower just to maintain that speed, but luckily that 
>  number is not large.  So my conclusion is that you need to 
>  minimize any parasitic losses, such as engine friction, 
> rolling  friction and so on to get the best mileage.  Engine 
> friction  losses rise rapidly with engine speed, so I think a 
> slow engine speed  is needed to keep those losses low.  
> 
> I have a 90 Vette  with TPI and a six speed, and the gas 
> mileage it gets when driven to  try and get mileage is just 
> amazing.  At 55 mph in 6th gear, the  engine is just turning 
> over at 1250 RPM.
> 
> My thoughts  are that you may not need the smallest engine you 
> can find, but an  engine that makes enough torque at a low 
> engine speed to allow it to  cruise at a low engine speed.  
> Oh, and use a manual transmission  so you can control what 
> gear it is in.
> 
> Scot
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