4.3L to ?? swap.

1998_K1500_Sub said:

Yup, I like that plan. I do something similar. @Supercharged111 as well. We're all thinking along the same lines, but perhaps with minor differences in our objectives.

When I'm not pulling a trailer, I opt for a tune that downshifts more readily and goes into PE more readily, because those events occur during passing, acceleration lanes, etc. which are brief and where I like the quick response.

I also have an aversion to downshifts that'll immediately rev my stock L31 engine to >3000RPM (it dies-off above 3500 anyway), so I require LOTs of TPS input to initiate them.

When pulling a trailer I'll tune differently to reduce shifts (hunting) and reduce extensive PE; I'll simply tolerate the performance. Of course, at very heavy throttle, downshifts and, when appropriate, PE are warranted. I don't want to be running in PE for minutes at a time

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I like just enough PE delay that when I put the hammer to the floor, the transmission can make a clean, smooth downshift before the engine ramps up to full power. I feel like enabling PE from a cruising situation for a WOT pass before the transmission downshifts could beat on the clutches without any real benifit. You can see mine drops into PE almost as soon as the downshift is completed.


The engine does not seem to miss a beat doing it that way either. Power comes on smoothly and quickly.

I love how this thread went from ripping a defunct 4.3L out and wondering what to replace it with, to let's discuss to how tune ECM's and stay completely off topic.

So, in case anyone is interested, my lack of progress on the 5.7L now is because I have two other projects in my way. One being the Wife's 67 Buick. We're doing an EFI conversion. Believe me this is the last resort. Didn't matter what we did to that 300ci, it REFUSES to idle, runs rich, and stalls out when coasting in traffic. She just wants the damn thing to be a reliable driver. For anyone wondering, we didn't just wake up one day and decide to do the swap. LOTS of research, and this: https://www.efisystempro.com/sniper/holley-sniper-2gc-efi-system-550-865-865-866

Next, I have to tear the dash out of my Trans Am once again. NOT looking forward to that, especially since it barely went back together the second time w/out turning into a crusty mess.

........digression.....

L31MaxExpress said:

I like just enough PE delay that when I put the hammer to the floor, the transmission can make a clean, smooth downshift before the engine ramps up to full power. I feel like enabling PE from a cruising situation for a WOT pass before the transmission downshifts could beat on the clutches without any real benifit. You can see mine drops into PE almost as soon as the downshift is completed.

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The engine does not seem to miss a beat doing it that way either. Power comes on smoothly and quickly.

xc_hide_links_from_guests_guests_error_hide_media

Click to expand...

I love the data display. What ECU are you logging, the 0411 or other?

I watched the MAP when you first tip in, it appeared to peak at 28.64". What was your elevation (above sea level) when you made this measurement, 1000' or so? Or was there a hurricane nearby?

Using the timestamp (in seconds) given by YouTube, WOT is just before 3s (2.7s maybe). The RPM starts rising rapidly thereafter, I presume b/c the downshift has begun.

Around 3.7s it appears the shift is completed, as the engine RPM is no longer rising as rapidly.

Right about 4.5s I see the injectors jump from ~11.3 to ~14.3 and the O2 sensors react, so I assume that's PE coming in ~2s after WOT. The engine is coincidentally passing through 4000RPM in the video; I'm guessing RPM isn't material here.

Acceleration from 55-75 took about (9.3 - 4.1)s = 5.2s. The resulting acceleration's about 3.8MPH/s (5.6ft/s^2, ~.17G)... back of the napkin anyway.

IAT was around 60F, so a cool day.

1998_K1500_Sub said:

I love the data display. What ECU are you logging, the 0411 or other?

I watched the MAP when you first tip in, it appeared to peak at 28.64". What was your elevation (above sea level) when you made this measurement, 1000' or so? Or was there a hurricane nearby?

Using the timestamp (in seconds) given by YouTube, WOT is just before 3s (2.7s maybe). The RPM starts rising rapidly thereafter, I presume b/c the downshift has begun.

Around 3.7s it appears the shift is completed, as the engine RPM is no longer rising as rapidly.

Right about 4.5s I see the injectors jump from ~11.3 to ~14.3 and the O2 sensors react, so I assume that's PE coming in ~2s after WOT. The engine is coincidentally passing through 4000RPM in the video; I'm guessing RPM isn't material here.

Acceleration from 55-75 took about (9.3 - 4.1)s = 5.2s. The resulting acceleration's about 3.8MPH/s (5.6ft/s^2, ~.17G)... back of the napkin anyway.

IAT was around 60F, so a cool day.

Click to expand...

The P59 but that histogram works for both the 0411 and P59.

Elevation is about 1,200 ft where I ran that.

I will take your napkin calculations a bit further. If all my unit conversions are correct. I believe I am at about 7,000 lbs right now. I have not changed how the thing is loaded but plan to hit the CAT scale on my way home tomorrow.

Ignoring the minutes on the datalog, 55 mph was at 37.621 and 75 mph was 42.831 seconds for 5.21 seconds from the instant the datalog touched 55 mph and 75 mph respectively. The total force required to accelerate 7,000 lbs from 55 to 75 mph is 608,413 ft/lbs. That force applied over 5.21s is an average of 212 hp. I have done a few coast down tests to calculate how much hp is required to keep the thing rolling from wind and rolling resistance. In neutral at 65 mph it is approximately 70 hp and at 75 mph it is about 100 hp. If I pick the middle ground of that acceleration test and add the coast down power loss to the acceleration force, I get 282 hp. Then add in the assumed 25% drivetrain loss of the 4L85E in 2nd gear with an unlocked converter and 10.5 14-bolt. 282/.75 = 376 hp. The engine RPM was 3,900 @ 55 mph and 4,988 @ 75 mph. Add them together and divide by 2, giving an average RPM of 4,444 rpm. 376 hp x 5252 / 4444 = ~444 ft/lbs. The average engine torque output is in the 450 ft/lb ballpark during that run.

I also pulled the data from a run that ended up from 70 mph to 83 mph in 2nd gear. That run was 70 mph at 45.884s and 83 mph at 48.684s. Total acceleration force of 465,436 ft/lbs. That force applied over 2.80s is 302.3 hp. Using the 100 hp of the 75 mph coast down I come up with 402/.75 = 536 hp. 70 mph @ 4,600 rpm and 83 mph @ 5,400. Average of 5,000 rpm. 536 hp x 5252 / 5000 rpm = 563 ft/lbs.

Now the fun part, average both of those numbers and you get a shade over 500 ft/lbs. Average the HP numbers and they are in the mid 450s. With the truck intake I saw 412 whp @ 5,600 with a locked torque converter in 2nd gear and 397 whp with an unlocked converter. 397/.75 = 529 hp at the crank. I saw 430 ft/lbs @ 3,400 rpm with the converter unlocked at about 15 ft/lbs less with it locked. 415 ft/lbs / 0.80 = 518.75 ft/lbs at the crank. ~20% loss to approximate torque loss at lower rpm where torque peak occurs. Driveline losses increase with driveline RPM.

Seems the math is not all that far off no matter how you dice it up. Perhaps one was slightly uphill and the second run was slightly downhill. Also two different points in the powerband coming into the torque curve early on one run and coming into the higher end on the 2nd. 7,000 lbs with a small block is not a race car but it does run well for what it is.

L31MaxExpress said:

The P59 but that histogram works for both the 0411 and P59.

Click to expand...

What software are you using to generate that display?

L31MaxExpress said:

I will take your napkin calculations a bit further. If all my unit conversions are correct. I believe I am at about 7,000 lbs right now. I have not changed how the thing is loaded but plan to hit the CAT scale on my way home tomorrow.

Ignoring the minutes on the datalog, 55 mph was at 37.621 and 75 mph was 42.831 seconds for 5.21 seconds from the instant the datalog touched 55 mph and 75 mph respectively. The total force required to accelerate 7,000 lbs from 55 to 75 mph is 608,413 ft/lbs. That force applied over 5.21s is an average of 212 hp.

Click to expand...

Assuming a constant .17G acceleration (from my prior post), delivered HP is 174HP at 55MPH and 238HP at 75MPH. Averaged that's 206HP, so our crude numbers jibe. (Edit: Note that I've NOT calculated the "average HP" here, I've simply averaged two HP numbers to see if they're close to @L31MaxExpress' number. A bona fide calculation of "average HP" requires a different approach, such as he did.)

L31MaxExpress said:

I have done a few coast down tests to calculate how much hp is required to keep the thing rolling from wind and rolling resistance. In neutral at 65 mph it is approximately 70 hp and at 75 mph it is about 100 hp.

Click to expand...

Nice. I've meant to do something similar but haven't.

L31MaxExpress said:

If I pick the middle ground of that acceleration test and add the coast down power loss to the acceleration force, I get 282 hp. Then add in the assumed 25% drivetrain loss of the 4L85E in 2nd gear with an unlocked converter and 10.5 14-bolt. 282/.75 = 376 hp.

Click to expand...

Aren't powertrain losses... amazing? We work so hard to glean all the engine HP we can (let's ignore fuel efficiency), and yet so much is wasted as heat in the powertrain.

L31MaxExpress said:

The engine RPM was 3,900 @ 55 mph and 4,988 @ 75 mph. Add them together and divide by 2, giving an average RPM of 4,444 rpm. 376 hp x 5252 / 4444 = ~444 ft/lbs. The average engine torque output is in the 450 ft/lb ballpark during that run.

Click to expand...

You're going right into the rabbit hole I opened for you I would have done the same calculations last night except I was tired and didn't care to guestimate your vehicle weight, powertrain losses or wind drag.

L31MaxExpress said:

I also pulled the data from a run that ended up from 70 mph to 83 mph in 2nd gear. That run was 70 mph at 45.884s and 83 mph at 48.684s. Total acceleration force of 465,436 ft/lbs. That force applied over 2.80s is 302.3 hp. Using the 100 hp of the 75 mph coast down I come up with 402/.75 = 536 hp. 70 mph @ 4,600 rpm and 83 mph @ 5,400. Average of 5,000 rpm. 536 hp x 5252 / 5000 rpm = 563 ft/lbs.

Click to expand...

That's nice torque from an NA 383SB. I won't bother recreating your numbers, our approaches are similar and generally identical.

L31MaxExpress said:

Now the fun part, average both of those numbers and you get a shade over 500 ft/lbs. Average the HP numbers and they are in the mid 450s. With the truck intake I saw 412 whp @ 5,600 with a locked torque converter in 2nd gear and 397 whp with an unlocked converter. 397/.75 = 529 hp at the crank. I saw 430 ft/lbs @ 3,400 rpm with the converter unlocked at about 15 ft/lbs less with it locked.

Click to expand...

I trust you've tweaked your TCC lockup to maximize acceleration, or at least to improve on some personal objective you might have (e.g., I lock mine up a bit early in normal driving and keep it locked most of time b/c I like the "feel").

I also did one last one 75-99. As expected the resistance inreases and the power available to accelerate decreases but not by a lot.

1998_K1500_Sub said:

What software are you using to generate that display?



Assuming a constant .17G acceleration (from my prior post), delivered HP is 174HP at 55MPH and 238HP at 75MPH. Averaged that's 206HP, so our crude numbers jibe.



Nice. I've meant to do something similar but haven't.



Aren't powertrain losses... amazing? We work so hard to glean all the engine HP we can (let's ignore fuel efficiency), and yet so much is wasted as heat in the powertrain.



You're going right into the rabbit hole I opened for you I would have done the same calculations last night except I was tired and didn't care to guestimate your vehicle weight, powertrain losses or wind drag.



That's nice torque from an NA 383SB. I won't bother recreating your numbers, our approaches are similar and generally identical.



I trust you've tweaked your TCC lockup to maximize acceleration, or at least to improve on some personal objective you might have (e.g., I lock mine up a bit early in normal driving and keep it locked most of time b/c I like the "feel").

Click to expand...

HP Tuners Scan program.

My van started with an advertised 245 hp net at the crank new and made 185 whp and 250 wtq with the Hecho en Mexico replacement engine when it still had the 4L65E and 10 bolt. The heads on that engine were pure garbage. They did not break 220 cfm @ 0.450. The 383 is signifigantly more powerful than the 230ish crank hp that 350 made. The OE cats may have been partially plugged at that point too because shorty headers, high flow cats and a muffler swap made a big difference in the power it made when I put them on.

I have part throttle lockup the way I like it and the engine seems to run best. I need to implement WOT lockup again. I will have to play with the WOT lockup to figure out at what point the additional efficiency overcomes the torque multiplication. I know the switch over point on the dyno is about 4,200 rpm so I will start there in 2nd gear. That is easy to figure out but sometimes does not exactly jive in real world acceleration. Below 4,200 the torque numbers are higher unlocked, above 4,200 they were higher locked.

To calculate power from 55 to 75, you subtract the initial kinetic energy from the end kinetic energy, and then divide by time.

KE is 1/2mv^2.

If you do this in SI, you get a result in joules per second (Watts), then convert to HP.

Edit ...

I decided to plug it in and got 212.31 HP

Alright people. I don't know how this thread went from engine swapping to computer tuning, but here I am getting back on topic. Where I last left off, I was going nuts trying to my crank machined was all worried about the rods having to be modified. All that is in the past now.

My current progress, continuing from THIS THREAD.

I have the pistons, rings, and conrods all installed now. The rotating assembly has plenty of lube, so I spun it once or twice. It moves like butter

I also noticed that the oil pump pickup tube was moving a little too freely. I could do this by hand:





So, I used a 21mm wrench to tap the pickup tube in just that much further, then *GASP* spot welded the tube in place. It's not going anywhere now.

The camshaft is going in next because in order to put the oil pan on, I need the timing cover installed. This requires the camshaft to be installed. Fun...

How high off the bottom of the pan will the pickup sit? I want to say 1/4"-3/8" is where you want to be. Plus spot welds are for n00bz, you gotta commit.

Supercharged111 said:

How high off the bottom of the pan will the pickup sit? I want to say 1/4"-3/8" is where you want to be. Plus spot welds are for n00bz, you gotta commit.

Click to expand...

So, what I did was put the pickup tube high enough so that when I set the oil pan down on the block, it would move where it would just clear the oil pan. Then, I removed the oil pan and moved the tube down JUST a bit. I'm going to say 1/4" sounds pretty darn close.

LOL @ gotta commit!

This is my latest progress, just this afternoon. Went to install the camshaft. It slid in like butter.



Then, lol, I noticed I forgot to install the freeze plug behind the cam. Try as I might, there wasn't enough clearance, with the engine on a stand, to install that plug. It went in cockeyed. Hard to tell from this pic, but it's not right.



It's a good thing I didn't throw out the old head bolts yet, because I needed them to lift the engine off the stand. Then, I put a metal folding chair under the engine to keep it from spinning, while the hoist took all the weight. Worked nicely. I had full access to the cam freeze plug then.



Much better!



Then, of course, for every step forward, there's two steps back. I'm missing the cam retaining plate in the front of the block. Now, I've labeled and stored all my parts pretty effectively for this build. That plate is gone. I don't know where it went. That's not my main concern. The bolts that hold that plate to the block look small. Not sure what size they are. Hmm.....

Also, I have to get another timing set. I've learned from multiple engine builds - replace the timing chain and the gears! I have to order these things. Hope I'll find that cam retaining plate, too.