Fw: [Diy_efi] Lumpy engine in closed loop cruise

Sat Oct 22 06:54:58 UTC 2005

Rick and Lee,
I hear what you are saying, and I agree on 70 MPH as a cruising 
speed. Above that air drag comes into play, and I think 85MPH is 
bit ambitious for "cruise" The Lotus is a slippery body, so it 
may be realistic.
In the case of the Lotus, the turbo is adding what a NA manifold 
would have plus 5 PSI. so its making about 10-11 PSI. so as Mike 
suggests in his post, the motor seems to be working harder than 
need be.
Air leak somewhere, or MAP sensor faulty, or not suited to turbo 
use?

When you referred to "slightly below absolute zero" don't you 
mean slightly below atmospheric?
BTW if you have worked out a way of obtaining pressures less 
than absolute zero, patent it.

Geoff H

From: "Rick McLeod" <dunvegan at sbcglobal.net>
To: <diy_efi at diy-efi.org>
Sent: Saturday, October 22, 2005 6:38 AM
Subject: Re: Fw: [Diy_efi] Lumpy engine in closed loop cruise

I would agree, I have 3 volvo's w/ factory turbos and
at 70 MPH w/ just a slight uphill load the vac/boost
will approach zero, then return to vac side on the
downhill untill bottom and load returns and cruise
calls for power to continue on flat land, at which
time it is between those extreemes, of course when I
pass, it blows by zero and well into boost, but that's
my problem w/ my lead foot :-)
--- "Lee M. Lemoine" <llemoine at gmail.com> wrote:

> With a turbocharged car, a lot of times light load
> crusing is right below
> "absolute zero" so to speak... only a light bit of
> vaccum, which really is
> 'almost boost' so to speak (if the turbo wasn't
> there, there would be lots
> more vaccum)
>
> -- LL
>
> On 10/21/05, Mike <niche at iinet.net.au> wrote:
> >
> > At 04:12 PM 10/21/05, you wrote:
> > >I think what is happening here is a
> misunderstanding of "cruise". My old
> > brain may be behind the times,
> > >but to me 85 MPH is a bit over cruise. (unless
> it's an F1 or CART -
> > tongue in cheek).
> >
> > Thats really only 136 Km/Hr, bit fast for the
> freeway I guess,
> >
> > When I used to go country in the olde ford escort
> with 1600cc I used to
> > happily
> > 'cruise' at 140 to 150Kms/hr, no turbo, not even
> WOT, somewhere around
> > 75%,
> > so his setup with some boost suggests his valve
> timing might be out or
> > he has a reasonably serious exhaust restriction...
> >
> > Looking forward to doing my block tomorrow with
> kids, depending on what
> > I find I just might really do my block !
> >
> > <chuckle>
> >
> > Rgds
> >
> > Mike
> >
> >
> >
> >
> >
> > >Geoff H
> > >
> > >
> > >----- Original Message ----- From: "Mike"
> <niche at iinet.net.au>
> > >To: <diy_efi at diy-efi.org>
> > >Sent: Friday, October 21, 2005 1:57 PM
> > >Subject: Re: [Diy_efi] Lumpy engine in closed
> loop cruise
> > >
> > >
> > >>At 12:19 AM 10/21/05, you wrote:
> > >>>Why to you say it is heavy load ? they is
> almost no boost. 0.3 bar max
> > which is nothing really.
> > >>>Throttle is about 5-10% so the turbo is just
> ticking over.
> > >>huh ? Did I miss-read when you said:-
> > >>
> > >>"In 5th gear, trying to hold steady 85 mph, 3500
> rpm, MAP about 100-130
> > kPa"
> > >>
> > >>Am I correct in seeing that as absolute manifold
> pressure at that cruise
> > ?
> > >>
> > >>To me that says you are at close to atmos
> pressure in your manifold to
> > >>keep it at 85mph, thats a fairly high pressure
> for cruise - isnt it ?
> > >>
> > >>>How do I richen it up, that is one of my
> problems. If you can the VE
> > tabels will the BLM not pull it back.
> > >>
> > >>Dont know anything about your ECU, maybe
> aftermarket performance
> > >>people can help. However, I have occasionally
> had similar problems,
> > >>came down to electrical connections on air flow
> meter, the ECU
> > interpreted
> > >>this as faulty and switched in and out of limp
> mode.
> > >>
> > >>If the car is more than 5 yrs old really worth
> checking connectors,
> > often
> > >>just cycling them (plugging in and out a few
> times) can help diagnose.
> > >>
> > >>Other thing that occurs, make sure all your low
> voltage leads
> > >>are well away from your high tension (EHT) . A
> common problem on the
> > Nissan
> > >>engine used here in the commodore is the cyl 1
> ignition lead being
> > really
> > >>close to the crank angle sensor leads and the
> tags breaking so there
> > >>isnt the normal separation, this allows high
> tension voltage noise to
> > >>get imposed on low voltage signals this can
> cause ECU to misread
> > >>crank signals, in your case make sure the MAP is
> not being misread
> > >>because any high voltage leads cannot corona
> discharge influencing
> > >>the main sensors. On one forum in Australia we
> had one guy who went
> > >>through 4 crank angle sensors - suffice it to
> say - he didnt know having
> > >>good EHT leads right next to low voltage leads
> would or could be an
> > issue
> > >>ie. Even brand new good leads allow some corona
> effect...!
> > >>
> > >>Fortunately its not as if its plasma ignition,
> that would be far worse
> > >>
> > >><chuckle>
> > >>
> > >>Rgds
> > >>
> > >>Mike
> > >>
> > >>
> > >>
> > >>>Dermot
> > >>>
> > >>>
> > >>>
> > >>>>Bit of a heavy load for cruise,
> > >>>>
> > >>>>And yes does sound a bit lean, can you richen
> it up by
> > >>>>20% and observe the effect ?
> > >>>>
> > >>>>Rgds
> > >>>>
> > >>>>Mike
> > >>>
> > >>>
> > >>>Regards from
> > >>>
> > >>>
> > >>>Mike
> > >>>Perth, Western Australia
> > >>>VL Commodore Fuse Rail that wont warp or melt !
> > >>>Twin tyres for most sedans, trikes and
> motorcycle sidecars
> > >>>http://niche.iinet.net.au
> > >>_______________________________________________
> > >>Diy_efi mailing list
> > >>Diy_efi at diy-efi.org
> >
> >>http://lists.diy-efi.org/mailman/listinfo/diy_efi
> > >_______________________________________________
> > >Diy_efi mailing list
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> > >http://lists.diy-efi.org/mailman/listinfo/diy_efi
> >
> >
> > Regards from
> >
> >
> > Mike
> > Perth, Western Australia
> > VL Commodore Fuse Rail that wont warp or melt !
> > Twin tyres for most sedans, trikes and motorcycle
> sidecars
> > http://niche.iinet.net.au
> > _______________________________________________
> > Diy_efi mailing list
> > Diy_efi at diy-efi.org
> > http://lists.diy-efi.org/mailman/listinfo/diy_efi
> >
>
>
>
> --
> Sincerely,
>
> Lee M. Lemoine
> http://www.turbochargedsoul.com/
> > _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>

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