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Re: Dyno Day success! (kinda long)



Wow, good shit Ben!  117.9 HP to the wheels (I'm assuming that's SAE 
corrected and not actual, right) is a lot of power for what you got under 
that hood!

My first (baseline) run with 41,000 miles on the car was corrected to 106 
if I remember correctly. Actual was 109.6 -- I scanned the wrong graph to 
put on my website (www.scirocco16v.org under "Press").  With the 
coast-down, I came up with 123hp at the motor...  So basically, anything 
over 106 is what you gained with your mods... i.e. you got 12hp more out of 
the motor.  Which also explains why you're faster than I am. :)

Mine made 110.0 lb-ft of torque, but again, that's actual.  Corrected was 
108 if I remember... so despite an overly rich mixture, you're still ahead 
of the game.

I'd love to see that curve though.

And remember, the benefit to mixture is bell shaped at full throttle, at 
all revs... so basically, running lean loses power less and less until just 
past stoich, and then overly rich falls off... albeit slower.  So if you're 
*too* rich all over, there will be gains by leaning out the mixture.

The other thing to consider is that the engine goes open-loop at full 
throttle -- so it's ignoring the O2 sensor.  Correct me if I'm wrong of 
course.  So your O2 sensor not working would have had no effect on 
performance on the dyno.  But if your car is running way rich due to DPR 
adjustment, it might have hurt performance.  I don't think so, personally, 
because while your car is running rich, it's not overly rich IME -- just a 
little teeny bit of black smoke at high revs, which is exactly what you want.

Don't change a thing with your mixture, just get that O2 sensor back on to 
get the car running more efficiently at part throttle.  And enjoy it -- 
according to the Jason-o-Meter, you got yourself a nice 136hp motor.(*)   :)

Jason

*  The 136hp at the motor figure was obtained by using the same drivetrain 
losses as my car displayed on a coast down measurement.



At 01:48 AM 10/23/00 , you wrote:
><snip>
> >
> >I think everyone (except Ben) was pretty pleased by their performances.
>
>  Well, first of all, this was a great time!  Second, a working o2 sensor
>is a very good thing to have...especially when trying to dyno!!  ; )
>
>   the details...
>
>My 1.8 16v (TT exh, Euro intake, K&N air filter, and lightweight flywheel)
>did two base runs on the Dynojet (2nd run was best)
>  HP: 117.9  Torque: 109.5
>
>Here's the problem... : /
>
>  after the 2nd run Brett and I check the timing and then check the fuel
>mixture so that we can do a little "tuning" ... the whole point of the
>day!... and we notice that the o2 sensor isn't sending a good reading, so
>we can't set the mix.  And this means that both of my runs were done
>without a working o2 sensor!  Which means that my mixture was already too
>rich...helped me out in top end a bit, but took away some bottom end...
>I don't even know what the car could have done now (if the sensor was
>good)
>
>The source of the problem is that last month I installed a new o2 sensor
>(generic 3-wire) and I spliced it into the old connectors.  I was careful
>to make the solder connections correctly and everything...
>but I forgot about the hot exhaust gasses being hot enough to melt the
>solder!  The heating element on the sensor shorted out so I was basically
>running a single wire sensor...at the cat. (which doesn't get quite hot
>enough to make the sensor operate all the time).
>
>What have I learned?
>   If you are going to install a generic 3-wire o2 sensor, make sure that
>you solder the connections with a solder that will not remelt under the
>heat of the exhaust!
>
>Does anyone have another solution to this potential problem?
>
>I will just have to wonder now how the results would differ on the dyno...
>hmmmmm
>
>
>=====
>____________________________________
>Benjamin Harder
>86 Scirocco 16v
>81 Scirocco
>http://members.nbci.com/Scirocco16v/
>
>__________________________________________________
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>
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----------
1987 Scirocco 16v
1988 Mercedes 190E Sport Euro


http://www.scirocco16v.org


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