Tbi,efi for sbc400?

a_kelley said:
As far as I know, the older gm stuff is all done with chip programming and swapping. I'm sure someone somewhere has a canned tune for a 400, or simple enough to rescale a 305/350 fuel map for a 400 or alternately, scale the injector flow rate and/or scale the fuel pressure. You might still want to get it tuned if you scale the injectors or pressure.. I'd offer to help you out with that if you were closer to me.

or you could use the tpi intake, injectors, & sensors with the kit that @Scooter402 is building and keep the hei for ignition. (Basically a stand alone EFI board)

who was it on the board that I saw was chipping older gm pcms?
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Yeah stand alone was what I had in mind for the tpi and leave hei alone but I’d like to strip all the old wiring out and wire whole thing up new with one of the painless fuse boxes if possible!? electrical is my Achilles heel.. appreciate the offer tho
 
I've burned chips for tbi and TPI setups. While you could leave the distributor alone and go fuel only, I prefer letting the computer handle timing too.

Chipping a factory ecm requires some soldering skill to install a new electronically programmable prom chip Vs the stock uv light erasable chip that needs a $$ and harder to find uv chip eraser.

@Scooter402's setup is very DIY requiring lots of fine soldering, for a more expensive but pre-assembled setup look up a Microsquirt system from the makers of megasquirt.

You can get a microsquirt computer and 8'wiring harness for $388. It's capable of running 1 to 8 injectors with 2 injector circuits. Basically hook 4 inj to one wire the rest to the other for TPI or one inj to each on tbi. It can run the stock GM coil and ignition module to control timing with the right module. Check out their website for a PDF that goes really into detail on setting it up, read it several times and it'll start making sense.

It will require wiring but it should be simple splicing of connectors to the 8'harness.

You can basically use it with all the tbi or TPI sensors and injectors but it's a much more user modifiable ecu than the stock GM one.

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DynamicEFI

They have everything to tune it. I almost went this route and a bought a new harness for my k5 since I found a lot of issues with it being old and everything being brittle. I may have s whole TBI setup to sell soon I haven’t decided.
 
Tim C said:
I've burned chips for tbi and TPI setups. While you could leave the distributor alone and go fuel only, I prefer letting the computer handle timing too.

Chipping a factory ecm requires some soldering skill to install a new electronically programmable prom chip Vs the stock uv light erasable chip that needs a $$ and harder to find uv chip eraser.

@Scooter402's setup is very DIY requiring lots of fine soldering, for a more expensive but pre-assembled setup look up a Microsquirt system from the makers of megasquirt.

You can get a microsquirt computer and 8'wiring harness for $388. It's capable of running 1 to 8 injectors with 2 injector circuits. Basically hook 4 inj to one wire the rest to the other for TPI or one inj to each on tbi. It can run the stock GM coil and ignition module to control timing with the right module. Check out their website for a PDF that goes really into detail on setting it up, read it several times and it'll start making sense.

It will require wiring but it should be simple splicing of connectors to the 8'harness.

You can basically use it with all the tbi or TPI sensors and injectors but it's a much more user modifiable ecu than the stock GM one.

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I’ll look into the micro squirt harness I’ve used a painless before and was pretty simple setup
 
I believe tpi may be what I go with if I can find a donor at junkyard just not sure what all vehicle besides vette and canary had the 5.0 or 5.7
 
C.Berry said:
I believe tpi may be what I go with if I can find a donor at junkyard just not sure what all vehicle besides vette and canary had the 5.0 or 5.7
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You know this one time I researched enough to figure out how to run a 96-00 vortec front cover/timing chain/reluctor wheel and 96-00 vortec CMP sensor. That way you could run LS coils and an LS ECM to run the fuel map. You’d have to get creative with your wiring since the firing orders are different but it would allow you to run sequential instead of batch fire. I feel that’s worth the performance to go that route with a SBC 400 TPI build. Would be one hell of a stump puller.
 
Hmmmm I’ll have to read into batch fire before I can research into how to set it up! Lol
iwaxmyjimmy said:
You know this one time I researched enough to figure out how to run a 96-00 vortec front cover/timing chain/reluctor wheel and 96-00 vortec CMP sensor. That way you could run LS coils and an LS ECM to run the fuel map. You’d have to get creative with your wiring since the firing orders are different but it would allow you to run sequential instead of batch fire. I feel that’s worth the performance to go that route with a SBC 400 TPI build. Would be one hell of a stump puller.
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In my opinion batch fire isn't so bad, sequential idles smoother and cleaner idle emissions, but at higher rpm for performance the injectors are open longer than the valves anyway so the fuel still backs up in the runner sequential or batch.

The TPI setup fired all 8 at one time once per revolution as batch fire, the stock TPI computer only has one injector driver. That's how I'm running the 350 in my dads 67 c10

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I feel like batch would be a hell of a rumble idling if all injectors fire at once! I’ve still got so much homework to do on tpi swap that I’ll be busy for awhile lol
 
That's how they were in the 80s and 90s. The fuel just sits by the valve waiting for it to reopen.

I'd suggest reading as much as you can at the www.Diyautotune.com site, they make the megasquirt and microsquirt. Go to www.thirdgen.org it's a camaro website but there's a wealth of information about efi and tuning on the specific forum pages there. Also www.binderplanet.com has a really good tbi swap section. It's geared towards tbi swapping international scouts, but Thirdgen and binderplanet are where I learned all about fuel injection swaps for my old Ford.

Third gen has a huge FAQ thread with tons of links. Learning and swapping efi will be like drinking from a firehose so you'll want to go back and read everything several times.

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Like I said originally, an aftermarket 4 barrel efi system is self contained and self learning and can be done in a weekend. You'll spend a similar amount of money swapping anything else, but if you're set on junkyard TPI or tbi after reading up on everything, keep us posted, I've done both and I can try to help you figure things out if you get jammed up.

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thanks Im gonna read up on all of the swaps before deciding I still like the Holley sniper system an tpi the most tho it’ll likely be one of those two! I’ve read a lot of the info so far off of thirdgen.org a lot of posts on it there even some specific for the 400! I feel like by the time I get to reworking fuel system I’ll go with ease over coolness just bc it’s been 8 years oct since I’ve been to Harlan for fall crawl... sad but true
 
To echo what @a_kelley said, if I were you I'd scale up a fuel map for a 350 and scale the injectors as well. That would definitely be the easiest route to go.

To reply to what you mentioned earlier about 305 runners and torque, the TPI setup is identical on the 305/350 with the exception of the injectors and the ECM. The intake manifold, runners, and upper plenum are all the same. The only difference between runners/manifold is there was one of the earlier year cutoffs (I don't recall at this time which it is) that had a 9th injector for WUE that was later changed with the ECM tune. If I were to offer advice, I'd get the later (non-9th injector) manifold and run a speed density setup without a MAF. You'd need a MAP sensor instead. To add to your list above, you'd also need an intake air temp (IAT) sensor. It's generally the same thing as the CLT sensor, but sometimes they might be an open element vs a closed element like the CLT sensor. I believe the CLT sensor will work just the same as an IAT, though.

You may also need a vehicle speed sensor. I know I needed one when I ran TPI on my old 383. And just for the record, yes - it was a torque monster. :D If you do in fact need a VSS and do get rolling on this, I could possibly dig around in my bag of spare goodies in the garage and find one. If it will work for you, you're welcome to it (if you do this swap). It adapts between a mechanical speedometer sender off the transfer case and sends a square wave pulse to the ECM for vehicle speed.
 
For the money, the fitech go street 400 kit is hard to beat. The only downside is it doesn't control ignition. The Holley sniper is $999 pretty much anywhere and can run ignition with the right distributor.

That said, for Chevy stuff it's hard not to pick up a $500 5.3 and have the wiring and computer done for another $500 and roll on.
 
I guess I’m just an old Jalopy soul I love my old small blocks the look the sound the smell which will be gone with efi... Takes me back I suppose! Don’t get me wrong I like the 5.3 engine but with everyone basically in the world doing a LS swap, I like stickin to my roots even if it is just a cammed 6.6 with whatever type efi I end up going with! Lol
 
Scooter402 said:
To echo what @a_kelley said, if I were you I'd scale up a fuel map for a 350 and scale the injectors as well. That would definitely be the easiest route to go.

To reply to what you mentioned earlier about 305 runners and torque, the TPI setup is identical on the 305/350 with the exception of the injectors and the ECM. The intake manifold, runners, and upper plenum are all the same. The only difference between runners/manifold is there was one of the earlier year cutoffs (I don't recall at this time which it is) that had a 9th injector for WUE that was later changed with the ECM tune. If I were to offer advice, I'd get the later (non-9th injector) manifold and run a speed density setup without a MAF. You'd need a MAP sensor instead. To add to your list above, you'd also need an intake air temp (IAT) sensor. It's generally the same thing as the CLT sensor, but sometimes they might be an open element vs a closed element like the CLT sensor. I believe the CLT sensor will work just the same as an IAT, though.

You may also need a vehicle speed sensor. I know I needed one when I ran TPI on my old 383. And just for the record, yes - it was a torque monster. :D If you do in fact need a VSS and do get rolling on this, I could possibly dig around in my bag of spare goodies in the garage and find one. If it will work for you, you're welcome to it (if you do this swap). It adapts between a mechanical speedometer sender off the transfer case and sends a square wave pulse to the ECM for vehicle speed.
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I thought I read the 5.7 runners were bigger for top end and 5.0 were shorter which didn’t make sense bc also read they can fit in the same manifold. I assumed they meant ID of 5.7 is bigger for more flow at lower rpm higher gear and 5.0 were smaller ID for high rpm in lower gears!? Still in research mode on all of this but after watching a sniper install it’s cake to wire that unit up, but sniper dizzy is a lil more in depth I’m not sure what all benefits I get from computer controlling timing to be honest I know I hate not being able to time my 99 5.7 without having a damn computer tho lol
 
C.Berry said:
I thought I read the 5.7 runners were bigger for top end and 5.0 were shorter which didn’t make sense bc also read they can fit in the same manifold. I assumed they meant ID of 5.7 is bigger for more flow at lower rpm higher gear and 5.0 were smaller ID for high rpm in lower gears!? Still in research mode on all of this but after watching a sniper install it’s cake to wire that unit up, but sniper dizzy is a lil more in depth I’m not sure what all benefits I get from computer controlling timing to be honest I know I hate not being able to time my 99 5.7 without having a damn computer tho lol
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Nah, they're the same. There are bigger ID runners available obviously, but what came from the factory is the same for both engines.

The self-learning systems certainly have something to be said for them. I had considered one of a couple from time to time, but the cost kept stopping me. I was thinking finally that I would go with a FITech unit, or possibly even Powerjection (the latest to my knowledge was the Powerjection III). They seemed to be good bang for the buck. But then I started getting interested in electronics, it became a part of what I do, and here we are today.

Just to reply to your inquiry - benefits of computer controlled timing is that you know exactly what your timing curve is for a particular RPM and engine load (because you put it that way). If you know either by feel/sound/driving etc. that you need a little more or a little less timing in a particular area in the RPM range, you can go into your timing table and adjust accordingly instead of guessing by changing out springs/weights or fooling with a vacuum advance canister. Besides....we can only assume that those springs and weights in the dizzy kits are what they say they are without actually measuring them, perhaps doing a little math/Physics to determine if we actually are getting the advance by RPM that we think we are, etc. In short, I suppose I'm saying that the computer controlled timing is much more predictable and reliable. Set your base timing and off you go!
 
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