Tim,
You have hit the nail on the head. We were hoping we would go "too far" on
the CFM capability so that we would no longer wonder "how far can we go?"
To addend my previous post, removal of the JETII chip improves the topend
and eliminated the surge at the expense of the midrange "flattening" out.
In discussion with JET they feel they can preserve the midrange, add some
advance to the timing and richen the top end a few percent to improve the
perf. @ WOT. My truck is a 98 360 cuin R/T with "shorty" style headers,
factory dual down pipes and 3" factory cat back. I have a fresh air
induction on the stock air box with stock hat and K&N drop in filter. The
rear end ratio is 3.92-1. its an automatic (only thing offered in R/Ts )
and has 6300miles on it. I have a JET stage II chip but... The big question
is : what is required on the 360 to make it work with 700+ cfm capability.
It doesnt "slow down" with 700cfm, but its not faster either. To really
optimize, a cam change or rocker ratio change might do the trick, but
without a mopar SBEC to richen things up they probably wont work too well on
the 98 without someone elses computer mods... We may have hit on the reason
MOpe isnt ready to sell you what appear to be universal power increasers
(cam, rockers) for a 98 (their listing "stops" at 96 even though the parts
"will fit"... ) Im sure Jules has tested all of these combos on the 97-98s
right????
BKB
-----Original Message-----
From: T & J [mailto:jan@bewellnet.com]
Sent: Sunday, October 04, 1998 6:18 PM
To: dakota-truck@buffnet.net
Subject: DML: Re: R/T Big throttle body track testing (loong)
From:Tim Roller>magnum318@bewellnet.com
>Great update on the Holloway "Super " TB, and I commend you on such great
weather and testing conditions and the testing results. I feel I can't
recommend any feedback, because I don't know what you have done to the
engine as aftermarket parts or is it just stock, and only the 2 TB's used as
a testing procedure. From what I can see, if your truck motor is basically
stock and only maybe headers, and exhaust work done, the reworked stock TB
would fill in the needs for most of us. If you have extensive
valve-train(1.7's), cam, headers, Jet or Mopar Performance Computer firing
the injectors then from what I see is a serious lean condition on the upper
end of the mid-range to the rev limiter and maybe a new mapping of the
computer module is in order to take care of this to prolong the injector
discharge or just a more agressive injectors--maybe around 22 or 24 Pounds
per Hr. That 700 cfm is overkill for a mild stock engine--just like putting
on a bigger carburator. Looks good, but it's not necessary and performance
will be seriously affected.
-----Original Message-----
From: Bridges, Bruce <bbridges@alarismed.com>
To: 'dakota-truck@buffnet.net' <dakota-truck@buffnet.net>
Date: Monday, October 05, 1998 11:44 AM
Subject: DML: R/T Big throttle body track testing (loong)
>DML,
>I tried out the 700+cfm Holloway stage II throttle body at the track
>Saturday. Got some interesting results. The conditions: 75deg F, 70%
>humidity, 29.99 Atmospheric pressure.
>
>I started with the Stage I TB (see pics on the DML) this TB has stock
>butterflys was unshrouded and "cleaned up". disconnected the battery for 5
>min, reconnected and lined up: (note final mph are off due to track
>"problems"...
>Run 1, Stage 1 TB:
> R/T .628
>60ft: 2.319
>330ft: 6.395
>1/8ET: 9.801
>1/8 mph: 71.69
>1/4 ET: 15.32
>Mph 89.87
>Run2, Stage 1 TB:
> R/T .833
>60ft: 2.216
>330ft: 6.282
>1/8ET: 9.684
>1/8mph: 71.74
>1/4 ET: 15.209
>Mph 89.72
>all runs: transmission in drive. ended the test of the stage I since the
>track was getting crowded and the Big TB was calling my name!
>Run 3: Stage 2 TB
> R/T .617
>60ft: 2.304 (lots of tire spin)
>330ft: 6.404
>1/8ET: 9.832
>1/8 mph: 71.19
>1/4 ET: 15.409
>Mph 88.89
>Run4: Stage 2 TB
> R/T .759
>60ft: 2.275
>330ft: 6.362
>1/8ET: 9.781
>1/4 ET: 15.348
>Mph 89.04
>Run5 Stage 2 TB:
> R/T .753
>60ft: 2.302
>330ft: 6.379
>1/8ET: 9.782
>1/8mph: 71.77
>1/4 ET: 15.305
>Mph 89.77
>Run6 Stage 2 TB, Manually shifted
>R/T .674
>60ft: 2.213
>330ft: 6.363
>1/8ET: 9.817 (hit the rev limiter 2-3shift, ouch)
>1/8mph: 70.83
>1/4ET: 15.410
>1/4 Mph: 88.92
> hit the rev limiter on 2-3shift (manually) kinda slowed me down...hits
like
>a ton of bricks.
>Note the run6 60 ft time vs the run 2 60ft time. Extra wheel spin and
still
>the same time!!!
>My impressions:
>The R/T loved the Stage I TB combined with the exhaust mods and JETII
>module. It felt like it would go faster as the computer "caught on" to the
>combo. A great combo for the street cruiser thats wants snappier
>performance from their R/T for minimum bucks. I think my combo of mods has
>scrubbed around .5-.6 seconds in E/T from the stock config. The Stage II
>TB presents some mysteries/opportunities. On the track, it felt "softer"
in
>the mid range but pulled hard to redline after about 2500rpms. I had a
>significant problem with traction with the stage II TB as well but not with
>the stage I BUT my 60ft times (2.216 stageI vs. 2.213 stageII are
>equivalent! More grunt at the botom from the bigger TB, go figure?). Its
>hard to tell about the traction problem since the track had "aged" over the
>afternoon and probably had gotten more slippery since the first run. I
>didnt see the 14s I was hoping for, nor huge improvements from the big
TB...
>BUT On the drive home, I noticed a definite surge at WOT at freeway+
speeds.
>I continued driving putting about 2 more drivecycles on the truck. At that
>point I felt that I am getting to 90mph from 65 mph faster than ever, but
>after "extended" WOT at 3K + rpm I get the surge. This says to me that Im
>too lean at the top end. The R/T never surged with the stage I TB. Hmmm
>Frank suggested removing the JET chip to see if the WOT gets better. Ill
do
>that this afternoon. Sounds like more mods are needed... New comp mapping?
>Bigger injectors? Ill keep the list posted on what those might be as we
>get further along in the development process... Any suggestions to make
the
>big TB work?
>BKB
>
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