[DeTomaso] efi horse power gain

Kirby Schrader kirby.schrader at gmail.com
Mon Aug 10 15:23:27 EDT 2009


A definite issue. Just like trying to use a mass air flow sensor with IR!
:-)

My Pantera system uses throttle position only. I use a MAP sensor to
compensate for barometric pressure. The Haltech F9a can do manifold
pressure or barometric pressure, but since I did not have a plenum, I
went the route I did. It works fine.

The GT40 has a common plenum mounted to the base of the intake
manifold. This is a TWM setup with their 'wheel actuated' throttle
linkage mounted on top of the plenum. Each throttle body has a vacuum
hose running to the plenum and the MAP sensor is attached to the
plenum. So there is a 'common' vacuum.

However, with IR and a decent cam, even the 'common' vacuum is not
very constant. The TEC3r helps compensate for this with a feature they
call 'TPS blend'. You adjust a curve/map for how much throttle
position input you want vs manifold pressure. So at low rpm's, you add
a lot of TPS bias and as the rpm goes up, you can rely on manifold
pressure. It works really nicely once you get your head around what it
does and how to adjust it.

Not sure I understand your pulses statement. Are you saying the ECU
measures each pulse of vacuum from each throttle body? The ones I'm
familiar with measure the manifold pressure as a single entity. There
is no attempt to find pulses. That'd be real tricky with longer hoses
giving different response...
If someone claims to do this, I haven't seen such a system. I guess I
need to read up on this mega system called FAST.

If you used all throttle position, the TEC3r would not need to know
anything about the manifold vacuum, I think. More reading to do. After
all, Will might give me more grief if I don't know the answer to that
one!
:-)

Later,
Kirby

On Mon, Aug 10, 2009 at 12:59 PM, Ken Green<kenn_green at yahoo.com> wrote:
> I guess the only difference I can think of between an IR system and a system
> with one or two throttle bodies feeding a common plenum (a tunnel ram like
> system) is the MAP sensor signal.  Just seems like it could be tricky?  4
> pulses per revolution versus 1/2 pulse?  But I think that not all EFI
> systems need MAP sensors?  I think the TEC-3 and FAST both do???
>
> Ken
>
> --- On Mon, 8/10/09, Kirby Schrader <kirby.schrader at gmail.com> wrote:
>
> From: Kirby Schrader <kirby.schrader at gmail.com>
> Subject: Re: [DeTomaso] efi horse power gain
> To: "Ken Green" <kenn_green at yahoo.com>
> Cc: wkooiman at earthlink.net, "De Tomaso List" <detomaso at realbig.com>
> Date: Monday, August 10, 2009, 6:23 AM
>
> Ken,
>
> Thought about your comment over the weekend and I'm not sure what the
> difference would be with an IR system... If the throttle bodies are
> synchronized so they work good at low rpm and idle, then I would think
> it would be the same as any other system. Should be transparent to the
> 'tuner'. When I had the GT40 on the dyno, the guy didn't even ask or
> seem to care that it was IR. But then, maybe he wasn't a 'good' tuner!
> :-)
> As a side comment, he was not familiar with the TEC3r at all, but once
> I showed him how it worked and where stuff was (the VE table made his
> eyes light up... Ah! OK!! I'm good with that!), he was happy.
> And like I said before, I drove away happy with another 40HP.
>
> And Boyd mentioned that someone recommended inside rails being better
> vs outside rails. I'm still struggling with this. The only thing I can
> think of is the length of the connecting hoses being shorter on the
> inside setup. Shorter hose, better fuel distribution/pressure. My
> rails are on the outside on my Pantera; inside with the GT40. Another
> possibility is the direction of the injector spray... inside rails
> point the injector more toward the intake port. But if you have a tall
> throttle body, then I wouldn't think this would make that much
> difference since it would be spraying towards the side of the throttle
> body anyway.
> I will say that when you put the rails on the inside, it gets REALLY
> crowded in there with the linkage and the injectors and the wiring.
>
> Ah yes... the 'experts'. In my experience, on and off the job,  the
> way to find out if they are experts or not is start asking in depth
> questions. If you get blown off by comments like 'don't worry about
> that', 'I've done it for years', etc. as answers, then they are not
> experts. They just think they are.
> :-)
>
> FWIW,
> Kirby
>
> PS: Wow... thanks for the kudos, Will!
> Dangerous territory you're skirting there... Me? An EFI expert?
> I just have two systems that I installed and have tuned myself.
>
>
>
> On Sun, Aug 9, 2009 at 2:29 AM, Ken Green<kenn_green at yahoo.com> wrote:
>> I'm not sure what the difference is between Bosch and Lucas, but if you
>> are
>> going after high HP, I think you want low impedance (aka, peak & hold)
>> injectors.  A lot of stock ECUs can't provide the power for low impedance
>> injectors, but both the TEC-3 and FAST ECUs can.  The advantage is that a
>> low impedance injector opens quicker, so if you have a high flow rate
>> injector, you can control it better at low fuel demand.
>>
>> I have been told that it is easier to tune the FAST ECU, but that may
>> depend
>> on who does the tuning.  I think you can actually spend more on dyno
>> tuning
>> than what you pay for the ECU, so it's probably best to get hooked up with
>> an experienced local tuner and get the ECU he likes to tune.  It also may
>> be
>> important that the tuner has done 8 stack systems, but I'm just
>> speculating
>> on that.  Like someone said, an EFI system is only as good as it's tuned.
>>
>> And, every expert you ask will give a different opinion.
>>
>> Ken
>> --- On Sat, 8/8/09, boyd casey <boyd411 at gmail.com> wrote:
>>
>> From: boyd casey <boyd411 at gmail.com>
>> Subject: Re: [DeTomaso] efi horse power gain
>> To: "Kirby Schrader" <kirby.schrader at gmail.com>
>> Cc: wkooiman at earthlink.net, "De Tomaso List" <detomaso at realbig.com>
>> Date: Saturday, August 8, 2009, 5:00 PM
>>
>> I have been speaking to Gary at twm induction and they actually use a
>> weber intake manifold and machine it to adapt the injectors . He said
>> that the FAST computer was the way togo now adays. The system Mad dawg
>> has was he top of the line back when he got it but the new fast system
>> is supposed to be supierior. The important factors are sequentail
>> injection vs batch injection, the speed of the system and how many
>> injectors it cam control. Also lots of the Weber style EFI have the
>> injectors and fuel rails on the out side and thats supposed to be a no
>> no. Another big factor is the injectors. Gary told me the Bosch were
>> far supierior.  ( cost around $300 or $400 more then the lucas
>> injectors. Many of the systems are designed as EFI for dummies. No
>> fuel return, no computer pprogram adjustmment neccesary. It seems to
>> me if your going to bite the bulet for $6500.00 + you may as well do
>> it right or just  go with a holley commander for around $2000.00.
>>
>> Boyd
>>
>> On Sat, Aug 8, 2009 at 6:33 PM, Kirby Schrader<kirby.schrader at gmail.com>
>> wrote:
>>>
>>> Ah, yes.... another person doing
>>> IR EFI on a GT40. Let us know how you get on!
>>>
>>>
>>> Jack Houpe, Mike Trusty and myself all have a TWM setup with a TEC3r (Jack uses a TEC2)
>>> on our GT40's.
>>> Each one of us attacked the twin tank fuel feed setup differently.
>>>
>>>
>>> I need to re-plumb my fuel system. I have a 'better idea' than what I am using now.
>>> On 8 Aug 2009, at 11:23 AM, Julian Kift wrote:
>>>
>>> I am in the initial stages of an EFI retrofit on the GT40 with a TWM IR
>>> system. Even after getting a good deal on the TWM throttle bodies and the
>>> ECU it has cost far more than I care to tell in $$ and time (it's all the
>>> little stuff, plus the complexity of twin tanks in that application
>>> requiring a swirl pot etc.). I constantly ask myself why I didn't just
>>> buy
>>> a
>>> Weber 48IDF set up and may even still do that.
>>>
>>> For the Pantera I have a Kinsler mechanical unit that I will convert to
>>> EFI and the ECU will be the DTAFAST (out of the UK), it is as capable as
>>> a
>>> MOTEC at about half the cost.
>>>
>>> http://www.dtafast.co.uk/
>>>
>>> Julian
>>>> Date: Sat, 8 Aug 2009 10:54:49 -0400
>>>> From: boyd411 at gmail.com
>>>> To: wkooiman at earthlink.net
>>>> CC: kirby.schrader at gmail.comdetomaso at realbig.com
>>>> Subject: Re: [DeTomaso] efi horse power gain
>>>>
>>>> The EFI set up I am looking at and considering is basicaly the same
>>>> one Mad dawg has. It is a twm Induction stack (looks like webers) The
>>>> ECU I am considering is the FAST ( I spoke to dawg and this is a more
>>>> upto date ECU then he has) Another key component are the injectors.The
>>>> two things I don't have are Mike Trusty and the CASH! I'm working on
>>>> the cash but I don't know what to do about Mike.
>>>> Boyd
>>>>
>>>> On Sat, Aug 8, 2009 at 9:57 AM, Will Kooiman<wkooiman at earthlink.net>
>>>> wrote:
>>>> > There's a very dramatic initial negative increase.  In most cases, the
>>>> > initial increase is the carbureted HP * -1.
>>>> >
>>>> > After a year or two of fiddling around, EFI catches up.
>>>> >
>>>> > Then you get smart and buy Mike Trusty a plane ticket.  You treat him
>>>> > right,
>>>> > feed him, and brag about how your tires hook really well.  Then M.T.
>>>> > fiddles
>>>> > for 15 minutes, and finally EFI surpasses your carbureted HP.
>>>> >
>>>> > But then you need better tires.
>>>> >
>>>> > -----Original Message-----
>>>> > From: detomaso-bounces at realbig.com
>>>> > [mailto:detomaso-bounces at realbig.com]
>>>> > On
>>>> > Behalf Of Charles Engles
>>>> > Sent: Saturday, August 08, 2009 8:46 AM
>>>> > To: boyd casey
>>>> > Cc: Kirby Schrader; detomaso at realbig.com
>>>> > Subject: Re: [DeTomaso] efi horse power gain
>>>> >
>>>> > Dear Boyd,
>>>> >
>>>> >
>>>> >                  Perhaps Kirby Schrader would comment on this.   He
>>>> > had
>>>> > one
>>>> >
>>>> > of the Haltech EFI systems installed on his already healthy engine
>>>> > back
>>>> > in
>>>> > the mid nineties and he has first hand experience about the before and
>>>> > after
>>>> >
>>>> > performance.  He was very happy with the change.
>>>> >
>>>> >                             Warmest regards,  Chuck Engles
>>>> >
>>>> >
>>>> >
>>>> > ----- Original Message -----
>>>> > From: "boyd casey" <boyd411 at gmail.com>
>>>> > To: "De Tomaso List" <detomaso at realbig.com>
>>>> > Sent: Friday, August 07, 2009 10:50 PM
>>>> > Subject: [DeTomaso] efi horse power gain
>>>> >
>>>> >
>>>> >> Can anyone tell me what kind of horsepower increase one could expect
>>>> >> from the addition of a quality professionally setup sequential efi to
>>>> >> a Cleveland  engine?
>>>> >>
>>>> >> Boyd
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