Jon,
So true! 13.5 A/F @ WOT w/ 700cfm TB @ 4900rpm. Injector roll off protocol
for at least the 98 computer keeps duty cycle below the magic 80or so % to
avoid injector hang, so with nitrous the limitations are real and dangerous
without enrichment!! I like to go fast, but Im going for the long haul too!
The surge could well be an injector hang below 4900 rpm due to extreme duty
cycleing the injectors! Need to go with a boost in fuel pressure @ WOT to
avoid tossing a piston top out the exhaust pipe (nasty smell too). But in
reality (new info) the stock injectors are not capable of delivering enough
fuel at the stock fuel pressure beyond the comps roll off protocol so Id up
the injector size/type too (Thanks Frank!!) my best 60ft is a 2.216, but Ive
got a CCR/T, with spare, tailgate and cooler of pop in the cab. alright, so
Im not serious enough.
BKB
-----Original Message-----
From: Jon Steiger [mailto:stei0302@cs.fredonia.edu]
Sent: Friday, November 06, 1998 4:12 PM
To: dakota-truck@buffnet.net
Subject: Re: DML: R/T 14.60 for real, no tricks,no juice
On Fri, 6 Nov 1998 Dyno05@aol.com wrote:
> The times I have posted with my R/T were all done with no Nitrous and with
> radials. The 14.60 was done in 58 degrees with 50 percent humidity. I
have
> run 14.65 in 78 degrees but 39 percent humidity. This vehicle likes low
> humidity and a cool motor. In about 75 degrees with 50 percent humity I
> average, 14.80 to 85. The first time I raced it bone stock I ran a 15.09
with
> the airbox out. 15.25 is my worst time ever, with real bad wheelspin, and
on a
> hot humid day.
> The only modifications I have done is a JET stage 2 module and my own
fresh
> air intake. I remove the tailgate and spare tire( worth 135 lbs) My
best
> 60 foot time and it is my average is 2.00 seconds flat. I get the best
launch
> by spinning the hell out of the tires in second gear for about 4 seconds,
and
> then proceeding with 2 dry hops, or until it hooks hard. Then I stage and
mash
> it hard on the last yellow. That gives me a 2.0 always. if it spins bad,
on a
> bad run, I get a 2.2 But with a good burnout on the stock RSAs, I have no
> problems. On the juice however It will run low 13s on radials.
Those are some good times, for sure! Awesome 60' times for radials
too! (What psi do you run in the tires?) My best 60' is about 2.08
so far, with 2.1 - 2.2 being my average.
> As I said earlier, I just purchased slicks and will be trying spraying out
of
> the hole next fri. It should ,if my calculations are correct , should go
high
> 12s. The nitrous kit I have is a very simple one, It is from compucar, it
is
> caleed the street heat system. It is very very stealthy and takes only
about a
> half hour to put in. No solenoids or extra lines to run. Just a simple
bottle
> mounted in a duffle bag, the solenoid is on the bottle, you run the line
into
> the tube after the airfilter . That is it. You plug in the solenoid to
your 12
> volt source and the button is in there too. The o2 sensor senses a lean
> condition from the extra oxygen in the nitrous, and in turn automatically
> enrichens the fuel. I have made about 12 passes with it with no ill
effects.
> I have noticed some surging though in the top of second gear and third but
not
> often.Only on 3 runs did it surge, and only once did I deem it neccesary
to
> get out of it. Feel free to mail me direct if you have any speed secrets
or
> want any tips from me.
YIKES!!!!! YIKES!!!! YIKES!!!! =(
You mean there is no fuel enrichment whatsoever? What about a fuel
pressure cutoff? You're playing with fire there... The engine does
not use the oxygen sensor at WOT, only at partial throttle. At
WOT, the computer uses lookup tables to determine the amount of fuel
to use, and doesn't even look at the oxygen sensor! You can run full
lean at WOT, and the engine won't care and won't do a thing to prevent
it. They're set up to run rich at WOT, but not nearly rich
enough to compensate for nitrous! Bruce (a fellow DMLer) was getting
a lean condition on his '98 R/T just from a larger (700cfm vs 500cfm)
throttle body, so I'd hate to see what your A/F ratio is when you're
on the juice!!
If I were you, I'd immediately stop using that setup at least until
you have a way of determining the air/fuel ratio when the juice is on.
(If for no other reason than to satisfy your curiosity.) Depending
on your paranoia level, you might also want to tear into the engine
to make sure that you haven't damaged something already.
You might have some trouble trying to explain to your local
Dodge service manager why your pistons look like someone went
hog wild with an oxygen torch... They might refuse warranty
service (pretty obvious that nitrous use was the cause) and
you'd be shopping for a new engine out of your pocket...
Do what you like, but I just got the heebie-jeebies when I read
your post; you're playing russian roulette there fer shur...
There's an excellent book about nitrous oxide written by David
Vizard in the SA Design Series (I think...) Its available through
Summit, and I highly recommend it to anyone using or considering
the use of nitrous. Read through it once, and I think you'll
get the heebie jeebies too! ;-)
Good luck!
-Jon-
.--- stei0302@cs.fredonia.edu ----------------------------------------.
| Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
| '96 Dodge Dakota v8 SLT CC (14.58@93.55), '96 Kolb FireFly 447 |
`--------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'
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