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Dyno tuning
great numbers dan. eighteen runs for 200 is a good deal. I'm hoping to see
your netfews car one day.
On 8/13/06, LEF <rocco16@sbcglobal.net> wrote:
>
> An interesting read, to be sure.
> I need to convince my youngson to quit messing around, finish the
> MegaSquirt, and take his turbo'd MkI to the dyno .
> Thanks, Dan.
>
> larry
> sandiego16v
> ----- Original Message -----
> From: Dan Bubb
> To: scirocco-l@scirocco.org
> Sent: Sunday, August 13, 2006 4:07 AM
> Subject: Dyno tuning
>
>
> LONG, LONG, LONG!!
>
> Finally decided that it was time to stop farting around and put the
> nephew's
> (Mike) car on a dyno and actually tune it.
>
> Couple interesting things came out of this.
> The first was that we wasted about 5 runs trying to fix the engine
> running
> lean at low RPM boost. We kept richening up the lean area at 3500 and
> below
> and kept seeing the 4500 RPM range richening up with no change at 3500.
> Well
> there's the length of the exhaust pipe and there's about 10 ft of tubing
> to
> the dyno's WB and that was essentially delaying the signal about 1000
> RPM.
> 5 wasted runs figuring out the dyno WB had a significant delay.
>
> Once up into the higher RPM ranges the dyno WB was showing leaner
> running
> than Mike's Innovate LC-1 WB by about .5 AFR so we used that as
> calibration
> which was the point of using the dyno WB in the first place. So,
> basically
> we went back to Mike's original map that had a very consistent AFR from
> his
> tuning efforts, richened the whole boost portion of the map by .5 AFR
> and
> ditched the dyno WB. So, something to keep in mind and the most likely
> reason that dyno runs always seem to start off lean.
>
> The second thing was that despite all the effing around with AFR in the
> 12.5
> to 13.5 range, we saw no significant difference in power. Richening it
> up
> did stop the engine from pinging when boost first came in though.
> http://i9.photobucket.com/albums/a95/jdbubb/86%20JH%20Turbo/scan0001.jpg
> That was about as far as we could go with fuel tuning. I figured we were
> about done cause when we started we had some pinging.
>
> Mike's using a Cheapass (R) ball and spring boost controller that we
> cobbled
> up (works just as good as a Forge manual boost controller though!) and
> it
> allows boost to initially rise to 13psi, then brings it back to 10 psi
> and
> maintains that fairly well. That's why there's a big hump in the torque
> curve at 3800. That's also where we had some pinging.
>
> So, the next thing to try was spark advance. Again, at 3800 and 13 psi
> we
> were already, apparently, on the limit. So we progressively added more
> advance at higher RPM. 1 degree at 4200, 2 at 4800-6200 and 3 at 7000.
> We
> did this several times and the progression can be seen here:
> http://i9.photobucket.com/albums/a95/jdbubb/86%20JH%20Turbo/scan0003.jpg
> Advance at 3600 and below was unchanged, but the engine definitely liked
> more advance at higher RPM and we were able to bring the high RPM torque
> up.
> Advance at 6200 went from 17 to 23 degrees by the time we started
> pinging
> again.
>
> Lastly we tried increasing boost. We had essentially been tuning at 160
> kpa.
> Increasing boost only 1.5 psi brought fairly significant pinging (BTW,
> you
> should hear pinging on the dyno. It's almost like the engine's sneezing,
> but
> it's a really hard mechanical sneeze ;^) so we started bringing the
> advance
> in the 190 kpa range down to compensate. In the end we ended up with
> virtually the same power we had at 10 psi boost since we had to pull so
> much
> advance out. So, that was that. Back to 10 psi boost and call it a day.
>
> Also of interest is watching an engine on the dyno. They move around a
> LOT!!
> Towards the end of the day we could almost tell how well the run had
> gone
> just by watching the engine position. No top end, you could see it
> relaxing
> in the mounts! Last run, it was leaned back all through the run. ;^)
> First and last run comparison:
> http://i9.photobucket.com/albums/a95/jdbubb/86%20JH%20Turbo/scan.jpg
>
> Eighteen runs, $200, we'd learned a few things, got a shitload of data
> and
> picked up 13 peak hp with an even bigger difference above 5400. 186whp @
> 5400 on 10 psi boost and 220 lb-ft @ 3800. Maybe not huge numbers but
> this
> is an incredibly streetable turbo. Where before it was all about using
> the
> midrange and shifting early, now it's still pulling strong at 6500. ;^)
> Imagine Mike sneaking up on sooo many unsuspecting suckers driving this:
> http://i9.photobucket.com/albums/a95/jdbubb/86%20JH%20Turbo/100_0759.jpg
> What a kick in the butt to drive!!
>
> What's next? Mike's engine apparently isn't very detonation resistant.
> Gotta
> get around that and run some more boost.
>
> One of these days I'll have more power than my nephew! :^(
>
> Dan
>
>
>
>
>
>
>
>
>
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