Wish I would've done a Before and After with the Dragy.
Now that you’ve been all up in its business you know the engine better. Worth it!Observations -
- Amazing how much quieter a new roller setup is than a 30 year old flat tappet in terms of engine racket.
- Nice little hot rod bump to it at idle, annoying gas smell occasionally, even with cats and a solid A:F.
- Not sure how much is the change in injectors, and how much the cam, but I had to pull a lot of fuel down low (probably injectors) and add a lot in the upper revs (probably the cam).
- All of the OEM smog stuff was shot. AIR pump was freewheeling, thermactor tubing was packed full of carbon, and there was a colossal vacuum leak in the tubing to the fuel vapor canister that I missed the last time I had the intake off. Eliminating that vacuum leak required a few generous turns to the idle adjustment to get it to run.
Working on the details in the tuning, but overall drivability was great after a few miles with autotune and then a couple rounds of VE Analyze.
I tried to reuse the rubber VC gaskets, but no bueno, have a leak on the passenger side, so new gaskets this weekend. I want to tweak the distributor rotation a little, too. But, otherwise, she's back to driving.
I'd never noticed before that MAP load never gets to 100 at WOT. I'm so used to dealing with boosted vehicles, I didn't realize that naturally aspirated never got to baro. I wonder if a bigger throttle body would get that last 2-4 kPa?
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Some engines can never get to 100 KPA, and some engines can go well over 100 KPA. I’m not sure if it’s an efficiency of the engine type thing or what.
Anything is possible if you do it wrong enough. Like Nitrous backfire is what I was thinking.They can have VE greater than 100% thanks to valve timing and intake synergy (note that the one above is in several places), but MAP can't be higher than barometric pressure (about 101.5 kPa for me here in Raleigh) without boost.
Aaannnndddd.... I forgot to change the distributor gear. Thankfully, I decided to clock the distributor a little differently while I was changing the valve cover gaskets, and noticed that, in the 430 miles I'd driven it, the gear teeth were about 50% gone. I'm pretty relieved that I didn't procrastinate with the gasket change, or I would've been sitting on the side of the road somewhere wondering what in the world was going on.
It would lay down really hard at upper revs and occasionally miss, and I couldn't figure out why.
I stuck the distributor from the red truck in it until I can get a proper replacement.
Regarding Calculated fuel, Did you do the “Double injector size” with the 60’s or go exact? I’ve been wondering if and why it matters.A couple of things related to tuning that are noteworthy. Dialing this thing in to the level it was with 19# injectors and the stock valve train doesn't seem possible. I'm having to lean on O2 correction more than I did before, so I've turned up the PID response and given it a bit more range than previously. The correction can swing plus to minus for the same load/rpm range with the change in daytime temperature, even with similar MAT temperatures.
I've also raised my 30+ percent throttle shift points, both up and down, pretty significantly to make up for somewhat less of a midrange - it's more apt to lug a little bit in OD at low speed and light throttle on an incline, so I've set it up to downshift more enthusiastically.
Pluses are way better behavior when it does downshift all the way through WOT to the upshift. It's a nice upgrade.
Batch fire, 60# injectors, and a more cam.