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As promised, here are the first set of results from my before/after
tests. Up to now, my engine has been stock, save for the removed
snow screen. I have just installed an Euro TB and a G chip.
The short form: mid-range roll-on acceleration tests showed no
improvement.
I think I really need a K+N to take full advantage of the chip &
the TB. That's logical, actually, since the TB can't do anything
if there is the same restriction (the stock air filter) upstream
as with the stock TB. Also, the G chip only works off of the
amount flowed through the system, and the stock filter is
restricting the flow & not allowing the G chip to do enough
magic. (I already ordered a K+N stock replacement filter last week
from Pep Boys, and am hoping to get get it before the autox this
Sunday.)
Of course, that begs an obvious question: if I had gone to the
K+N filter as the ONLY upgrade, how much improvement will I see?
The throttle response DID feel better, but that could have been
because I removed a bit of slack from the throttle cable!
Anyway, here's the nitty gritty of the tests if anyone is interested:
My roll-on tests are timed runs between two RPM points, in specific
gears: second gear, from 2k to 5k, and third gear, from 2k to 4k.
A bigger range may be more meaningful, but for my purpose (auto-xing),
those are the RPM range where gains are the most important to me.
Also, I couldn't do tests in higher gears, because I didn't want to
be caught in possession of 5000 rpm in fourth or fifth gear on the
street! |-)
The street I did the tests on is a wide, fairly new 6 lane (3 each
way) divided street, no shops or residences on either side. The two
way-ness allows me to run tests in both directions to even out
the effect of elevation changes, as well as wind & air conditions,
etc. The streets are punctuated by left-turn lanes at decent
intervals so I can turn around quickly w/o having to wait at a
light (too time consuming).
I did 12 runs of each test, 6 in each directions. I cruised at the
start RPM (2k) making sure that the car is neither accelerating or
decelerating, then I floored the gas and hit the stopwatch.
I stopped th watch when the needle hit the target RPM (4k or 5k).
I threw out the slowest and fastest times, and averaged the rest.
I took care to make sure that the car has more or less the same
amount of gas, the same tire pressures, and the same configurations
e.g. no lights, no fans, no radio (!), etc.
The results w/ G chip & Euro TB were about a couple of hundreds
of a second slower than stock i.e. WAY inside the "noise" range of
the results and not a distinct gain or loss.
Here are my notes:
========= 04/20/98 ==========================================================
o All accessories off (no lights, no fan).
2nd gear, 2000rpm - 5000rpm
Low & high times (in []'s) omitted from calculation of averages
Steady at 2k, then floor throttle + start stopwatch; stop watch at 5k.
o Low & high times are in []'s; they are omitted from the calculation
of the average.
o Ambient temperature readings are from the MFA.
-------------------------------------------------------------------------------
o Stock:
98/04/20 12:15
Fuel: 3/4 tank
Temp.: 75 (start), 78-79 (end)
Wind 6mph out of S
Rel. humidity: 62%
Sunny
Road: dry
2nd gear 2000-5000
Direction #1 (JR BMW -> Braker)
5.41 [5.12] 5.25 5.28 5.19 5.22 / 5.270
Direction #2 (Braker -> JR BMW)
5.44 [5.53] 5.21 5.44 5.41 5.28 / 5.356
2nd gear 2000-5000, average: 5.313 secs
========= 04/20/98 ==========================================================
o Stock:
98/04/21 19:00
Fuel: 3/4 tank
Temp.: 68 (start), 68 (end)
Wind 12mph out of N
Rel. humidity: 32%
Sunny
Road: dry
3rd gear 2000-4000
Direction #1 (JR BMW -> Braker)
8.31 [8.55] 8.03 8.34 8.50 8.35 / 8.30600
Direction #2 (Braker -> JR BMW)
8.31 [7.53] 8.31 8.44 8.19 8.31 / 8.31200
3rd gear 2000-4000, average: 8.309 secs
========= 04/22/98 ==========================================================
o Tests with Euro throttle body & G chip:
98/04/22 12:00
Fuel: 5/8 tank
Temp.: 70 (start), 75 (end)
Wind 0mph
Rel. humidity: 28%
Sunny
Road: dry
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
2nd gear 2000-5000
Direction #1 (JR BMW -> Braker)
5.41* 5.35 5.37 [5.38] x.xx 5.31 5.13 5.32 5.29 / 5.296 (5.295 incl. last run)
Direction #2 (Braker -> JR BMW)
5.50* 5.35 5.32 x.xx 5.41 5.19 [5.03] 5.31 5.35 / 5.316 (5.321 incl. last run)
* first set of runs doesn't count 'cause I had the vent fan on.
2nd gear 2000-5000, average: 5.306 secs (5.308 secs incl. last run)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3rd gear 2000-4000
Direction #1 (JR BMW -> Braker)
8.56 8.35 8.50 8.53 8.69* 8.69 x.xx / 8.552
* I had the vent fan on this run.
Direction #2 (Braker -> JR BMW)
8.00 8.54 [8.06] 8.25 8.19 [8.85] 8.25 / 8.246
3rd gear 2000-4000, average: 8.399 secs
-------------------------------------------------------------------------------
- --
Andy Nguyen \ aqn@tivoli<img src=/i/dc.gif border=0 width=35 height=15> \ Tivoli Systems, Austin, TX \ 512.436.8229
Ave, XTela, morituri te salutamus.
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Thu Apr 23 22:46:28 -0500 1998