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Looks like it's my turn to give tbi swaps a go

So, 2500 miles on it since conversion and other than the initial timing display hiccup, it's been flawless. I live at 6200ft and routinely hit 12500 to 14500 and it's been great. Lots of logging so far but not a lot of tuning time. My BLMs are all within 4% of 128 with a semi conservative timing map. I'm planning on keeping going with it, still gotta refine the AE shot and my WOT fueling however I'm working on a 16197427 pcm swap as well for its maf, iat, and dual electric fan control. I have all the parts except the newer style knock sensor. This one is gonna be a longer term project as I have a few different ideas I'd like to toy with in the programming so I'm making a plug and play adapter for the 16197427. Making my intake for the maf with a Ford style airbox that is sealed and can be run as a snorkel, fed to the caddy bonnet

20161011_181409.jpg
 
Well, since I do a lot of driving during the week I've had a lot of time datalogging and tuning the 7747 and now have it dialed in. Due to being blocked from work due to the fires, I accidentally got bored and finished making my adapter for the 7427 and yesterday I started tuning it with a speed density bin. Now, the tbi 7747 starts and idles great compared to a carb, especially when its 32* outside, but the 7427 is worlds apart! After driving it on the 7427 today from the Springs down to Pueblo to grab a maf from a 6.0 I decided screw it and just wired up the maf and IAT and burned a bin. All I have to say so far is WOW. Right from the get go this thing was damn near dead on, only thing it needs is a little more AE for quick stabs at the throttle. Also got my Windstar fans in and wired up to replace the clutchless engine driven fan that was in the truck when I got it. So far so good, and for anyone on the fence about doing the $0D maf conversion, DO IT!!!!!!!!!!!!!
 
3200 more miles on the 7427 running $0D maf and all amazing and the only change I made was getting rid of a plugged up rotting turbo muffler and going with a walker 21054 (my new favorite muffler) and my typical outside the rail tailpipe routing.
The colon surgery to the exhaust free up all that restriction, yet due to the maf scale it needed no retuning. The burn 2 lives in my desk now, no longer plugged to the laptop 24/7 like when I was 7747 $42.
For those who don't know the truck, it's a bone stock 73 with this TBI added. No lift or gears (3.07s) th350/np203, and 33s added after a fender trim. truck average mpg driving to the gulches trailhead area was 21.2mpg
I had to take it down Hackett's gulch to the river to help with a multi vehicle recovery and ended up having to tow our other blazer most of the way back out of Hackett's (the ghettoflage 78).
Jake had his blue 1 ton k5 down there to recover a dead trans in LS Jeep buggy. Jake destroyed his winch, Ryan blew ghettoflage's front diff, and I bent my antenna, lol. It's ok, I want the windshield mounted antenna anyways!
 
I had to check that muffler part number, it's what I got but haven't installed. Care to elaborate on your thoughts on it? Sound? I was looking for the quietest muffler I could fine, the OEM muffler designs appear to be that, just haven't installed it yet. Toying around with the idea of a resonator too, but I have a feeling after the muffler is installed, the noise is going to be from the road, not the engine.
 
To me it sounds about like some of the factory mufflers that are on the throaty side. I have very little tailpipe on my truck, probably about 2.5' total and it's very quiet. It's not whisper silent, but has the tone that says v8 without being intrusive at all. I have no droning at any rpm or throttle position, and with windows up or down all I can hear is road and wind noise. If I go WOT you can hear that it's not a stock exhaust, but still not intrusive or annoying. Easy to have a conversation, talk on the phone, etc .

I'm headed up to go check the creek bank by my cabin in a bit, I'll grab some sound clips for you
 
That will be interesting. I'm going to be running full length exhaust, so I'm hoping it's the same, only road/wind noise.
 
OK, here is a couple of cell phone vids

Cold start (28* outside)
https://goo.gl/photos/bGzmV89muSprhZu3A

Warm idle in park
https://goo.gl/photos/Hh1D94UJ2nYd1Kou7

45mph roll, windows closed
https://goo.gl/photos/98rrYJMuTH5Erj3w8

My cab and door seals are in about average condition, no carpet but I do have the rubber mat, and have speedholes in my front floorpan, lol. Honestly, I can hear the intake note more from the MAF swap and Ford airbox. The 78 has a 3" in 3" out 50 series deltaflow with the same tailpipe as this one, and its noticeably louder and also has the flowmaster resonance. This Walker doesnt seem to bother the deer up by the cabin either.
 
Hmm, that's not bad at speed. Definitely far more noise from other components than the engine/muffler.

A bit more than I like at idle, but then again, idle can't be that bad in the truck, since there is no road noise.
 
Yep, it's not bad at all. At idle inside the truck all I can hear is the blower for the heater, not the exhaust
 
That's just a muffler, right?

If you posted already previous, apologies, but are you running manifolds?
 
I'm running stock manifolds into a 3" collector, into this muffler, then about 2' at most of 3" pipe for a kickout after the muffler
 
Well, it looks like swap #2 starts tomorrow morning on the ghettoflage 78. Details of parts going into this one are:

Spectra sp12l1h fuel pump and sender
Dst1830 distributor
Ks6 knock sensor
7427 (94/95) pcm
Gasket matched stock TBI intake
New 195* tstat
New radiator hoses
Katts lower radiator hose heater
SBC TBI with ultimate mods done
New feed and return lines from front to back
All emissions deleted physically and in tune
Sonic cleaned SBC 61lb/hr injectors
Adjustable FPR
5.3 truck MAF
Harness built by me
Tune by me (will be dialed in on Ostrich 2.0

Truck has a 355 I threw together last year with a decked late roller block, ported camelhumps, manifolds into single 3" with flowmaster, non-lockup 700r4 I built, and np203. As soon as it arrives, were throwing the intellitronix gauge set in it to replace the factory stuff too.

If anyone wants any specific details or photos, let me know!
 
What's the deal with the 5.3 MAF?

I'm guessing the PCM there is a "OBD 1.5" or whatever, and the MAF is a higher resolution piece than the old MAF's like I run?

Not that I'm having any issues with mine, but I'm curious what it takes to run the later MAF's. The early MAF's were pretty pricey last I looked.
 
The 5.3 MAF is a little bigger, higher resolution, and has the IAT built in so you dont have to run a separate IAT. They seem to go pretty cheap online, plus are all over the parts yards (in some of the Caddy's as well). I can post the MAF scaling table for them if you want to try one out some time
 
az_762_nato said:
The 5.3 MAF is a little bigger, higher resolution, and has the IAT built in so you dont have to run a separate IAT. They seem to go pretty cheap online, plus are all over the parts yards (in some of the Caddy's as well). I can post the MAF scaling table for them if you want to try one out some time
Click to expand...

I don't know all the tech speak for it, but I am guessing my ECM won't even work with the later MAF's. I know the limit is 255 in pretty much every parameter, and when folks were building pretty wild engines, the ECM and MAF couldn't "read" high enough. The PCM you are using is probably not limited to that 255 value.
 
The 7427 pcm still has a lot of the same limitations as the original 7747 tbi ecm. What part number MAF and computer are you using?
 
az_762_nato said:
The 7427 pcm still has a lot of the same limitations as the original 7747 tbi ecm. What part number MAF and computer are you using?
Click to expand...

Hmm, can't find the MAF PN online. Surprising. It's the "later" unit that doesn't use the external burnoff module, and it's Bosch, that's all I can remember. Apparently these (the one I run) are analog units, the 1985 was FM.

Computer is a 1227165. Which is not a real good one lol. No one ever figured out (or spent enough time doing so) to figure out why the data output freezes on them. Datalogging can be torturous, as it will simply stop outputting data at random times, and won't until the ECM gets a key off restart. :(

At some point I plan to go MAP, I've got all the parts, just haven't gotten the motivation to do so, since it's been working fine as-is.
 
https://docs.google.com/spreadsheets/d/12tafdyb5Rio1W1CGReNba3JXlmx9xB8ir0HqnWbN8u0/edit?usp=sharing

That is the MAF scale for a few different GM units. I'm using this setup as the go-to now due to how well the MAF handles flow changes compared to the tbi running SD. The 78 and the 73 are drastically different engine-wise, but the tune from still comes out within a few % in everything but timing due to the heads. the MAF is handling large elevation changes better than the SD was for me too. I live at 6200ft and routinely go to 14000ft and back for work and everything in between. The MAF seems to like the non "computer friendly" cams pretty well too
 
I suspect it is highly unlikely the earlier FM MAF's run the same frequencies per gms/sec as the later ones.

My MAF has given me no issues, but the plumbing of the MAP setup is much cleaner. Plus allows me to ditch the arguably terrible ECM. Not much more annoying than trying to record a log so you can make changes, and your data freezes.
 
Have you tried writing a pause into your datalogging software? I had to add one into the adx file I was using for ALDLdroid because it would glitch pretty badly at times
 
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