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Dyno tuning
Wow Dan, that is some good stuff! That car turns into a monster around
3500 rpms! $200 for those kinds of hp gains is a pretty good deal
considering people pay that much for an intake on their honda that gives
them 3 hp. :D Goes to show that Dyno tuning is really the only way to
get that extra bit out of whatever setup you are running. I'd be willing
to bet you could squeeze 10 hp out of a stock CIS-equipped car with some
crafty dyno tuning. Sure beats making adjustments and then ripping down
the street saying "hmm, felt better that time!" :)
--- Dan Bubb <jdbubb@verizon.net> wrote:
> 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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