RE: RE: RE: 4.7L V8 TB Spacer

From: Bernd D. Ratsch (bernd@dodgetrucks.org)
Date: Wed Aug 22 2007 - 12:53:53 EDT


What a lot of folks aren't understanding - and to correct Ray....it's not
the modification that's not working...it's the PCM programming. While the
TB by itself will make a difference, once you hit the PCM's limit on
"tuning" for the other modifications...bolting anything on will not gain you
anything. There's only so much the PCM can compensate for with airflow
(intake and exhaust modifications). What you have to do, and not just
stating "it doesn't work", is look at the fuel adaptives (all 26 cells -
STFT and LTFT). This will tell you where things are at and how much more
the PCM can compensate for. There are also software limits which
programmers can help with. Camshaft selection, head flow, intake flow,
exhaust flow, fuel/timing, and O2 readings all come into play.

So with that said - will a modified TB work on a basically stock engine -
yes...and they've been proven over time to work. Start getting too in depth
with the modifications (bolt-ons, etc) and you'll be heading off to the dyno
and (hopefully) finding someone to custom flash your PCM.

- Bernd

-----Original Message-----
From: Rick Barnes [mailto:rascal@scrtc.com]
Sent: Wednesday, August 22, 2007 11:19 AM
To: dakota-truck@dakota-truck.net
Subject: RE: DML: RE: RE: 4.7L V8 TB Spacer

I have a superchip, a K&N, and a catback, but noticed nothing from the new
tb, but it is nice and shiny so I left it on. I have no internal mods
whatsoever.

Rascal

-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Ray Block
Sent: Wednesday, August 22, 2007 9:40 AM
To: dakota-truck@dakota-truck.net
Subject: RE: DML: RE: RE: 4.7L V8 TB Spacer

> -----Original Message-----
> From: Kyle Kozubal
>
> Ray,
>
> So you are saying that Hughges, F&B, BBK, and Fastman
> (as well as other companies) are all selling products
> that have no performance gains whatsoever?

Did I say that? No....I believe I said "On an internally stock motor a
larger throttle body doesn't make any difference." I will condition that
with "if the stock throttle body is not a restriction". Now, on 4.7's,
Chrysler increased the throttle body size in 2001 to 68 mm from the 65 mm
used previously. Since mine is a 2000, I bought a stock 68 mm and indeed
picked up a little performance at the track. Reasoning that even the 68 mm
may be some restriction, I tried a ported 68 mm (about 3 mm larger than the
stock one). Oops, sorry, no gain anywhere. Not at the track, not on the
street. Then I got a Superchips controller that increased my shift points
by almost 400 rpm. Reasoning again that perhaps the higher rpm may make
better use of the larger throttle body, I tried it again. Nope, nothing.
I'm back to the stock one now and run the identical times and speed I did
with the larger one. I will keep it though in case I ever decide to do
some internal engine mods.

As for the four companies you mentioned, all make excellent products. All
have their place in certain engine combinations. Just don't believe all the
marketing hype. A larger throttle body eventually made an improvement on my
Dak, but not until I had increased the engine's breathing capacity through
cam, head and manifold changes along with 1000 rpm higher shift points.

> I have a performance chip, K&N FIPK, and a Flowmaster
> Exhaust...........all that I was hoping that a larger
> aftermarket TB would nicely compliment.
>
> Kyle

How did you measure the value of the products you already have? How would
you know if a larger TB made an improvement?

When "everybody says", or "Too many people have noticed", I would be asking
how they tested it. What sort of controls were in place to isolate this
change from everything else? (variables...like weather, driving style,
brand and octane of gas, other changes?)

I see a lot of folks buy the hot item of the day. In the process of bolting
it on, they decide this might be a good time to change plugs, wires, cap &
rotor, install a fresh air filter, change the oil and maybe put some air in
those low tires. They go right out and hammer it and "wow", that (name the
item) "really performs!" Then, if they also heard it should improve gas
mileage, they drive like granny for a week and "wow, look how much that
(name the item) increased my mileage!" And "all they did" was change that
one item!

Do you know that a change in the weather alone can alter your gas mileage by
a couple mpg? It can also improve or hurt track performance by several car
lengths in a quarter mile. Have you noticed that if your truck sounds
louder, it seems faster? But is it? How would you evaluate that?

Bottom line though, it's your money involved and if you choose to not
believe me I won't be offended. Maybe someone else reading this will
believe me and save their money.

Ray
2000 Grand Cherokee 4.7 - 15.40 @ 85.70
http://www.dragtruk.com/ENTRIES/20KM1FD2KWBP.html



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