Thanks and a bit abotu me. Was:Re: [Diy_efi] TBI or TPI?
Ashley Evans
hoshy
Wed Sep 14 19:09:35 UTC 2005
AFM is the crappy sprung-flap connected to a potentiometer used in early
motronic. Offers a notable amount of resistance to the air intake.
Thanks for the info on MAP vs. MAF. I prefer the idea of MAF for the
reasons you pointed out I just need to make sure the MAF I choose will
be able to read when the super is on full boost. I'm not planning on
running alot though.. maybe 5 - 10psi
Well, Scotland is part of the UK so I guess that counts :) Although I'm
sure there are many Scots who'd disagree. Nice to hear there's yet
another Linux man out there too! I'm sure we all know it's the way
forward :) (no flames please!!!)
If I ever do get around to carrying out the plan for my final project I
will indeed post up here. I'll probably need some help too! All the
code will be GPL too, and the whole project will be open of course.
Ashley
Rick McLeod wrote:
> Now for me to learn, what is AFM?
>
> BTW, from what I've experienced, forced induction
> manages easier w/ MAF than MAP as MAP is a calculation
> of air mas based on pressure and temp where MAF
> measures true air flow. I have cars w/ turbos both
> ways, and the more easily managed and more driveable
> seems to be the MAF based, but there are definite
> differences beyond that due to manufacturer, etc.
> I know little about supers so don't know how different
> that may be from turbos.
>
> And, btw, I'm a uk'r at heart, well sort of, if you
> consider you're northern neighbors in Scottland :-)
> and a linux fan also, so would be interested in see
> the results of your final project, hopefully you'll
> hang around and post them upon completion. Good luck
>
> --- Ashley Evans <hoshy at hoshy.co.uk> wrote:
>
>> Ah, I see. Thanks for the info. I'll look up that
>> book. I'm not
>> actually doing any conversion myself just interested
>> in how it all works.
>>
>> For anyone who's interested i'm running an '89 BMW
>> 318i (m40 engine)
>> it's a simple 8v sohc 4pot not great at the bottom
>> end but quite nice
>> above 4k.
>>
>> I'm going to be installing a unichip piggyback
>> management system to
>> allow me to map it properly and facilitate a move
>> from AFM to either MAP
>> of MAF. The community I'm part of
>> (www.e30zone.co.uk) rates the MAF
>> conversion quite highly but I'm going to be
>> installing an eaton m45
>> (mini cooper S) supercharger so I may go down the
>> MAP route from the
>> beginning.
>>
>> I do computer science at uni and for my final
>> project I'm hoping to
>> create my own fuel (maybe igniton) computer based on
>> real time linux
>> (I'm a huge linux fan!) that's really the reason
>> i'm here, and I just
>> enjoy reading the various discussions... and flames
>> :)
>>
>> Oh, I'm based in the London, UK btw.
>>
>> Ashley.
>>
>> Rick McLeod wrote:
>>> The late John Lingenfelter was one of the most
>> highly
>>> respected SBC authorities, he wrote a book
>> detailing
>>> modifying the SBC in many fashions, TBI, TPI,
>> RAM-Jet,
>>> LT/S versions, etc, including bolstering oil
>> systems,
>>> fuel, etc. I recommend getting a copy or borrowing
>> one
>>> from the library if doing any SBC work, it saved
>> me
>>> many headaches building both my TPI's.
>>>
>>> BTW, TPI is Tuned Port Injection, a form of
>> multi-port
>>> injection using a long runner design that was
>>> originally optimized to the 305, but adapted to
>> the
>>> 350 with good sucess. It falls apart at high RPM,
>> mine
>>> virtually quits at about 4500, but at 1000 rpm it
>> will
>>> put a moderate hill without downshifting, and
>> cruises
>>> at 75 to 80 at 30MPG at about 2400 RPM. This is
>> torque
>>> at it's finest!
>>>
>>> To make your choice, it depends on your needs, are
>> you
>>> going to drive it much, if not don't spend the
>>> time/money on TPI, but you'll really like what it
>>> brings if you go that route.
>>>
>>> BTW, I run a 700 trans w/ a 2400 stall converter,
>>> really comes off the line hard and strong since it
>> is
>>> well on top of the torque curve at launch, but w/
>> the
>>> lockup converter it doesn't impact MPG (read claim
>>> above).
>>>
>>> Hope this helps.
>>>
>>> --- Ashley Evans <hoshy at hoshy.co.uk> wrote:
>>>
>>>
>>>> Thanks, I even fully understood your description.
>>>>
>>>> So what is TPI? is that direct injection?
>>>>
>>>> The discussion on low end torque being better on
>>>> TPI, is that related to
>>>> the manifold length?
>>>>
>>>> Does anybody have links to the equations and
>> theory
>>>> etc related to
>>>> manifold design, volume, length etc. And info on
>>>> the resonance flap
>>>> used by some manufacturers?
>>>>
>>>> I'm sorry to hijack the thread with so many
>>>> questions :-/ Feel free to
>>>> ignore me.
>>>>
>>>> Regards,
>>>> Ashley Evans
>>>>
>>>> On 14/9/2005, "Rick McLeod"
>> <dunvegan at sbcglobal.net>
>>>> wrote:
>>>>
>>>>
>>>>> you're correct, TBI is Throttle Body Injection,
>>>>>
>>>> which
>>>>
>>>>> usually is the use of a carburetor body w/
>>>>>
>>>> injectors
>>>>
>>>>> to replace the atomization function under
>> computer
>>>>> control (other primitive means are used also).
>>>>> Therefore, most all intake manifolds are
>> relatively
>>>>> easy to conver to TBI, and I believe companies
>> such
>>>>>
>>>> as
>>>>
>>>>> Holly and Edelbrock and others make simple kits
>> for
>>>>> this.
>>>>>
>>>>> --- Ashley Evans <hoshy at hoshy.co.uk> wrote:
>>>>>
>>>>>
>>>>>> Sorry for the n00b. question. I mostly lurk
>>>>>>
>>>> here
>>>>
>>>>>> to read and learn.
>>>>>>
>>>>>> TBI and TPI mean what??
>>>>>>
>>>>>> I thought that TBI means Throttle Body
>> Injection,
>>>>>>
>>>> or
>>>>
>>>>>> am I sorly mistaken?
>>>>>>
>>>>>> Regards,
>>>>>> Ashley Evans
>>>>>>
>>>>>> On 14/9/2005, "Rick McLeod"
>>>>>>
>>>> <dunvegan at sbcglobal.net>
>>>>
>>>>>> wrote:
>>>>>>
>>>>>>
>>>>>>> Clearly TBI would be an easy swap, replace the
>>>>>>>
>>>>>> carby
>>>>>>
>>>>>>> w/ a TBI unit, add some computer, wiring, and
>> a
>>>>>>>
>>>> few
>>>>
>>>>>>> sensors and you're off and running.
>>>>>>>
>>>>>>> TPI is a much nicer solution, hence why GM
>> went
>>>>>>>
>>>> to
>>>>
>>>>>> it.
>>>>>>
>>>>>>> It's long runner design lends to very good low
>>>>>>>
>>>> end
>>>>
>>>>>>> torque, but in stock form has limited top end
>>>>>>>
>>>> RPM
>>>>
>>>>>> and
>>>>>>
>>>>>>> HP drops off toward the top end. That
>> shouldn't
>>>>>>>
>>>> be
>>>>
>>>>>> a
>>>>>>
>>>>>>> factor in your application, actually TPI would
>>>>>>>
>>>> be a
>>>>
> === message truncated ===
>
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