L31 Extreme Budget Build

[L31MaxExpress]

It's a shame they dummyproofed it to the point an experienced tuner has to struggle to this extent.

It is straight up bad, if I could fix the base tune like Holley or the old Accel systems it would be done. Scre Edelbrocks little calibration hand held on the older system or the app for your phone on the newer systems. It is nearly worthless for an experienced tuner. If it were a TBI computer, TPI computer, Black Box, 0411 or P59 it would already be running great.

 

[L31MaxExpress]

Finally have it running a lot better, not perfect but much better now than it ever has run before. I set the IAC to hit its target with the transmission in reverse. Idle thus a bit higher than commanded in Park/Neutral and drops smoothly right down to target when it goes into Reverse or Drive.

After driving it around this evening.

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OE gauges are actually surprisingly accurate as well. Mechanical oil pressure gauge was showing 50 psi at hot idle and the mechanical temperature gauge ~190F. Without the AC on, fan clutch engages at ~210F and brings it right back down to ~190F. I did swap the 180F for a 195F, I feel like the larger variation between thermostat opening and fan clutch engaging was messing with the learning some. It was dropping to 172F at times and Edelbrock states, needs to maintain 180F in the instructions. I noticed the 02 Learn flag was turning off showing a red flag when it was dropping to 172F and would turn green again when it would warm back up a bit, system is much pickier than the GM ECMs and PCMs in regards to coolant temp.

Some of the added smoothness and power that is now starting to become apparant could also very well be the engine breaking in more with the more miles driven.

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[L31MaxExpress]

I have this heavy thing to swap out now too, lol. After the alignment drives great, just the box and pitman arm have some slack. Should take care of it making it drive practically like new.

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[L31MaxExpress]

I meant to also say earlier, jammed it up on the highway while I was out and about, pinned the speedo needle at 80-85 cruising with other traffic for about 25 miles, then turned around and came back. The 350 was singing 3,000-3,200 rpm and just begging for more go pedal, but I resisted. Did not miss a beat, tracks straight, rides well and even handles decently.

 

[SNCTMPL]

I meant to also say earlier, jammed it up on the highway while I was out and about, pinned the speedo needle at 80-85 cruising with other traffic for about 25 miles, then turned around and came back. The 350 was singing 3,000-3,200 rpm and just begging for more go pedal, but I resisted. Did not miss a beat, tracks straight, rides well and even handles decently.

Can’t ask for much more than that.

 

[L31MaxExpress]

Can’t ask for much more than that.

The fact the fuel gauge only moved 1/8 tank was also a bonus. ~15 mpg would be darn good pushing a brick into the wind at 80-85 mph with no overdrive. Now that it has the headers, the tuning is closer and I am not laying into it out of every stop sign or stop light it seems like it sips on that $$$$ 93 octane fairly lightly.

 

[L31MaxExpress]

The highway romp did emphasize the need for new weatherstrips though. I put Metro brand on my 1983 back in about 2005 or 2006. They are still in practically like new condition. Probably should also do the window runs and felts as well.

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[L31MaxExpress]

Idling around in city traffic running the A/C with the 195F thermostat, the clutch fan starts to engage more around 208-210F and brings it back down to ~190F and releases. When the clutch engages it pulls the a/c pressures down enough to blow 29-30*F air before the compressor cycles. Very little fan noise from the clutch fan and no noticeable power loss.

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[L31MaxExpress]

I also remodeled the engine for the heck of it with a dual plane and headers with a free flowing exhaust vs the single plane and manifolds. Also modeled with the correct compression ratio. The software models of both setups also reflect the tremendous torque gains from the dual plane and headers.

492' cam, 10.1:1, single plane and manifolds
RPM-----HP-----TQ
2,000---133---349
2,500---180---377
3,000---230---402
3,500---273---410
4,000---302---397
4,500---322---376
5,000---326---343
5,500---314---300

492' cam, 10.25:1, dual plane, small tube headers. The bad part is with no overdrive, no lockup converter, etc it has me thinking of putting the cam that is in the 97s 383 in it when it comes out. The 271/284 @ 0.006, 218/228 @ 0.050 on a 108 LSA with 0.533 lift advanced to a 102 ICL shows it would make over 430 hp @ 6,000. I would have to swap in some 0.050" offset retainers to make that work though. Then again this is near perfect as it sits, no sense chasing more power at the expense of drivability and fuel mileage.

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[L31MaxExpress]

Also a bit of a surprise to me, ~100 miles on this since the tail pipes went on and they have not even built up soot yet. The wideband 02 sensor must be controlling the fueling very well for optimal fuel burn.

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