Jon,
You are right in that at WOT the fuel and ignition settings come from tables
within the ECM (Open Loop). At WOT the mixture is rich for two reasons, to
keep
the Cat cool, and for power, emissions regs. are a lot more lenient at WOT.
Additionally there are adaptive cells in the ECM to take up production
tolerances
between engines. What I want to do is push the mods right up to the point
where the computer can't adjust (lean condition). If we still have room for
improvement,
then we can go to someone like JET for a custom chip that will richen the
fuel. The computer actually looks at the O2 sensor(s) up to approx. 7/8
throttle settings,
most of the throttle settings will not be a problem. Most NOS kits that I
have seen actually run the fuel quite rich under NOS operation so I don't
think NOS would
be much of a problem, but I have never installed/played with these kits so I
would talk to the kit manufacture about mods before installation. The price
would just
be the mods. The TB that Bruce has was new, my cost on a new TB is approx.
$200.00 (1992 - 1998) for anyone who would want a new one. The nice thing
about
new is that they give you a new IAC and a new TPS. I have a friend that is
going to give me a couple of warranty 97/98 TB's. I still need to look at
the 96 to find
out what the difference is, and I have a couple of 95's to work with.
Additionally, cost for an early TB from the salvage yards out here in Calif.
is approx. $85.00
(92 - 95). I still need to get my hands on one of the V-6 TB's because I
don't want to leave these out. I really don't know what to expect with the
bigger plates,
because of the "black box", but we will certainly find out. In regards to
the price, we are not trying to make money on this, just cover costs and
take some of
"MAGIC" out of other peoples prices, and help some of our friends out.......
The machine work is really simple and straightforward. Second guessing the
ECM
is the hard part. I've got to tell you I have had a lot of fun doing the
work.......
Frank
> -----Original Message-----
> From: Jon Steiger [SMTP:stei0302@cs.fredonia.edu]
> Sent: Monday, August 31, 1998 5:22 PM
> To: dakota-truck@buffnet.net
> Subject: RE: DML: RE: RE: franks TB!!RE: Magnum Performance Throttle
> Body?
>
>
> On Mon, 31 Aug 1998, Holloway,Frank T wrote:
>
> > DML,
> > Here is where we are at with the TB's. The first one that Bruce
> installed
> > appears to be working fine (no check engine light, or dead spots off
> idle).
> > The next will
> > have larger thinner brass throttle plates and a stainless steel throttle
> > shaft installed. Hopefully he will be installing the new one the weekend
> of
> > Sept 12th. I will be
> > installing one identical to the new one for Bruce this coming weekend.
> Bruce
> > had some concerns about interference with the manifold and larger
> throttle
> > plates,
> > and I need to check this out on my truck (see if it is unique to Bruce's
> > truck), flow numbers will follow. Additionally, I'll be running my truck
> on
> > the dyno to check
> > for power and lean conditions. If everything goes according to plan, we
> > should have some additional numbers next week. Cost, we don't know yet
> but
> > were kicking
> > around a figure between $50 - $100 each, what do you think????
> > Frank
>
>
> Frank,
>
> I've done some porting on my TB already (knocked off "stonehenge"
> blocks,
> knife-edged the divider, removed the ridge in the bores) but I'm very
> interested in the larger bore one. I'll be looking forward to hearing
> your
> flow/dyno/mixture results.
>
> One concern that Bill (Tierney) and I were discussing at the track
> one night was about a possible lean condition. If the TB bores are
> bigger,
> I assume that would let more air through, so you'd need to up the fuel
> in order to keep that 14.7(?) ratio. It should be interesting to see
> how well the computer handles this below WOT.
>
> Anyway, the main concern was with running nitrous. At WOT, the
> fuel mixture will (I believe) come from the static tables within
> the PCM, and the O2 sensor won't be used to regulate flow. (I've
> heard that the Magnums run slightly rich at WOT, which might help
> a little.) Anyway, the concern is that the wider bores will lean out
> the mixture, and when nitrous is added... boom? The kits from NOS
> and the like are set up to increase the fuel to a specific flow, so
> the fuel plus the air from the TB plus the nitrous should be within
> tolerances. More air than stock from the TB might be a problem. I
> guess if I were to do a more or less custom nitrous setup, I could
> up the fuel a bit to compensate, but I'm not sure how much leeway
> there is with the manufactured kits.
>
> PS: Just so everyone's clear and there aren't any misunderstandings,
> would that $50-100 price include the TB, or just the work, plates, and
> shaft?
>
>
> -Jon-
>
> .--- stei0302@cs.fredonia.edu ----------------------------------------.
> | Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
> | '96 Dodge Dakota v8 SLT CC (14.85@90.72), '96 Kolb FireFly 447 |
> `--------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'
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