400 SBC TBI conversion in my COE hotrod project

[kscarguy]

I am attempting something very new to me. Swapping my hotrod truck to TBI Fuel injection. This is not something I have any experience with.

To begin, the vehicle is a 1941 Ford COE car hauler hot rod. The engine is a new 406 SBC, with slightly dished pistons, stock heads, longer rods, fresh cam (not too big, told by mfr. that it would work with the TBI). The trans is a 700R4, the cruise control is1970's Chrysler (not installed yet), the wiring harness is mostly from a 82 Chevy truck and it has dual aluminum fuel tanks . The plan is to swap the truck over to TBI. It currently gets 12 mpg on the highway running about 2300 RPM @70 mph on a Quadrajet carb.

So far: I have collected 90% of the parts I need.

Intake - Aluminum TBI intake from 1987 350. Center four holes elongated, manifold bead blasted and clean.
Throttle body - 1987 stock from 350=
Wiring harness - 1987 Chevy truck. Pulled apart and labeled.
Sensors - all sensors plugged into harness, weld bung for O2 sensor to be put into exhaust header.
Brackets - correct throttle cable/TV cable bracket, Cruise diaphragm/module from 1990 Chevy truck with linkage
Fuel system - both hard lines on engine and flexible stainless fuel lines to body from 1990 350 engine, fuel tank valve for switching between tanks
ECM - xxxx747 truck computer

Installing the manifold, brackets and even wiring the system do not scare me. What scares me is getting a decent working fuel system and programming the computer to work with the 400 SBC engine.

I am considering using the fuel pumps from a 2000 Chevy 3500 truck (without the pressure regulator on the pump) and putting an in-line regulator in the line. I do not know for sure what pressure the 2000 pumps put out. I think it is 45 psi. I was told that I should increase the pressure from 12 to 15 for the 400 engine. I could swap in stock pumps from 1987, but I am afraid they will be too low on the pressure.

I also am confused on the Adjustable Internal Fuel Pressure Regulator available for the Throttle body. I have no idea what this does. Will this allow me to increase fuel pressure?

If anyone has any advice on what I should do to make this swap work, please do not hesitate to share.
Thanks!

[Six_Shooter]

The internally adjustable fuel pressure regulator is just that, it allows the stock regulator that is located in the TBI injector pod to be adjustable. Yes, this will allow pressure changes, such as your proposed increase to 15 PSIG.

As far as the throttle body itself goes, you may find that the 350 TB is a little restrictive, depending on the actual RPM range you plan to run the engine in. If the revs are mostly under about 4500 then it should be fine, though I can see a need to change the injectors to larger ones needed regardless.

I would skip trying to use a factory pump (I say that even though I LOVE to use off the shelf OEM parts), and just go for a frame mount Walbro, or similar. This will keep the fitment easy, and no need for extra regulators, even though you shouldn't really need any extra regulators with the OEM pump you have thought about using. The FPR (Fuel Pressure Regulator) in the throttle body will take care of that.

As far as tuning goes, yes it seems daunting at first and it IS a steep learning curve, but it is a fun one. I will strongly suggest getting equipment that will allow you to emulate the EEPROM, for real time tuning, such as the moates.net Ostrich 2.0, or AutoProm. This will speed up both tuning time and learning, because you can see the changes effects as they are made.
Starting with a stock 350 bin, that is matched to your trans will be a great start and should allow you to start the engine and get driving around, though it won't be ideal, you shouldn't notice any real issues. 350 to 406 is only about a 16% increase in displacement, and shouldn't really effect initial driving sessions to get the tune squared away, just don't go beating on it until you feel the fueling and spark tuning is close.

The biggest effect on how an engine runs seems to be from the cam, mostly, I'm not negating other parts here, but the cam has a huge influence on how the vacuum is developed in the intake. I've tuned large duration cams, and it can be challenging, but is doable. If the .050 to .050 duration is less than about 210 degrees, I have found that most stock bins will run on them, while not ideal, they will start and run, without too much difficulty. The problem comes in when the intake pressure, or rather vacuum is less than about 15 in/hg (>50 kpa), at idle. A stock bin will think the engine is under load and start to pour fuel in, which will only make the situation worse.

Your saving grace here is that you currently have the engine running, so you can do some checks before hand to see if there will be any issues, such as the aformentioned intake pressure checks.

Just read up on tuning techniques and threads that people have created that document their tuning journeys and you will get an idea of what needs to be done. It makes a WHOLE LOT MORE sense once you actually start doing it yourself though. ;)

[kscarguy]

This is a built as a low RPM engine for street driving in a heavy truck. The cam is a Crane H-260-2. The Summit web site says it is not computer compatible, but the Crane rep said it was, because it was in the 400. I put a vacuum gauge on my engine and I had very strong manifold vacuum. If I remember correctly it was above 15 and I think it approached 18 in/hg at idle.

Basic Operating RPM Range:1,200-5,000 Intake Duration at 050 inch Lift:204
Exhaust Duration at 050 inch Lift:216
Duration at 050 inch Lift:204 int./216 exh.
Advertised Intake Duration:260
Advertised Exhaust Duration:272
Advertised Duration:260 int./272 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.427 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.454 in.
Valve Lift with Factory Rocker Arm Ratio:0.427 int./0.454 exh.
Lobe Separation (degrees):110

Looking back, I also see where I have an email from Harris Performance (tbichips.com) and they said I should run "18 psi fuel pressure", along with a custom chip to "remap the timing and fuel for the engine".

[Six_Shooter]

If that cam works anything like the H-260-2 that I had in my V6, you will have no problems. I ran that engine on stock EPROM(s) for a couple years. Having 18 in/hg is pretty good, you might even be able to improve on that with the EFI. ;)

Fuel pressure isn't really a good way to make up for a lack of injector, but higher pressure can help atomize the fuel better than a lower pressure. Tuning for the actual combination will always produce the best results. You may find a little less fuel pressure works better, or a little more, though most people run their TBIs at no more than about 18 PSIG, unless they have the late 454, which ran a higher pressure from the factory, 30 PSIG IIRC.

[blue68deville]

Sounds like a cool project, I think it will work out great. There is a ton of good info on this board, use the tutorials when you start tuning and it will all make sense.

Forget that you ever heard of the tbi chips guy. He told me that my current setup would never work, and has advised others poorly.

[kscarguy]

OK, already forgotten LOL


I am making some progress. I down-loaded TunerPro RT and also got the ASDU.bin off of the diy-efi site. I put that into the "BINS" folder under my TunerPro files.

However, I am having trouble downloading the $42-1227747-V3.xdf and xds files from this site. They keep coming in as .PHP file extensions. Do they also get stored in the "BINS" folder?

[blue68deville]

Mine downloaded the same way, I'm not sure how to change them but they work anyway as PHP. I just make sure the name I type in matches what the file actually is, it will just have php at the end.
XDF goes in bin definitions folder and ADS in acquisitions (?I think)
The bin's saved on mine in 2 versions, one was a txt file. Make sure you open the .bin and not the .txt, it will do weird stuff.

[EagleMark]

It's your version of Windows... Right click and save file as.

[BLG355]

Forget that you ever heard of the tbi chips guy. He told me that my current setup would never work, and has advised others poorly.

I am proof of this! You are at the correct place if you want tuning or help tuning.

[kscarguy]

I've been reading about EFI all day and now my mind feels like overcooked oatmeal...everything just raises more questions.

Will the hydraulic (non-roller) cam work with the TBI?

Should I swap in a VE table from someone who has done the 400 TBI swap or just work from the 350 table?

Should I swap injectors from the 454 into my 350 throttle body? If yes, what tables will I most likely need to modify to compensate?

Most likely I will buy the APU1 emulator and set up an ECM with the correct socket. After I get it running correctly, I will then burn a new chip and put it into a spare ECM and install that in my truck. Then I can use the first ECM as a tool for doing other/future EFI conversions. OR Is there a better way?

[Hog]

The TBI truck engines were non-roller cams for the most part.

peace
Hog

[kscarguy]

The TBI truck engines were non-roller cams for the most part.

peace
Hog

whew!

[kscarguy]

Some more seriously dumb questions that have probably been asked 1000 times...I read the tutorial and devouring all the information I can find. I'm learning a lot.

I think I know the answer, but my first question is, will it run? If I physically install everything and connect up the stock ECM, will the 400 run? I think the answer is yes. More importantly, will it be drivable? This, I do not know.

My 7747 computer is for a 1990 5.7, automatic. Do I just put it all together and see if it starts? Is there a better method or a better starting place (better BIN)? I ask this because I can't afford to have the truck be unmovable and stuck in the garage since I may have to relocate soon...

[lionelhutz]

It should run at least well enough to move it around.

That cam is just fine for EFI, in fact I'd almost consider it a little on the small side for a 406 engine.

I would use a dual plane carb intake with an adapter plate.

It should work with the newer fuel pump. I have run a high pressure pump meant for port injection just fine. Others have mentioned the same. The advantage with a newer fuel canister is that it has a jet pump to keep the canister full and it won't ever stumble due to the pump sucking air. A frame mounted pump would work OK too but you may need to take measures to ensure no air reaches the pickup. I have used a sump on the bottom of the tank with success.

You could just add 16% to the VE table to begin with, unless you don't have the programming equipment yet.

Your thoughts on the tuning and using a final chip are good. That gives you the ECM to use for tuning another project.

[Fast355]

It should run at least well enough to move it around.

That cam is just fine for EFI, in fact I'd almost consider it a little on the small side for a 406 engine.

I would use a dual plane carb intake with an adapter plate.

It should work with the newer fuel pump. I have run a high pressure pump meant for port injection just fine. Others have mentioned the same. The advantage with a newer fuel canister is that it has a jet pump to keep the canister full and it won't ever stumble due to the pump sucking air. A frame mounted pump would work OK too but you may need to take measures to ensure no air reaches the pickup. I have used a sump on the bottom of the tank with success.

You could just add 16% to the VE table to begin with, unless you don't have the programming equipment yet.

Your thoughts on the tuning and using a final chip are good. That gives you the ECM to use for tuning another project.

I wouldn't add it to the VE, I would adjust the BPWC and BPW vs EGR table.

[lionelhutz]

Yes, you are correct. Modify the BPW to match the new cylinder displacement (and injectors if you change them).

[kscarguy]

I wouldn't add it to the VE, I would adjust the BPWC and BPW vs EGR table.

Forgive me for being a newbie...

BPWC? -- I do not see anything with that exact acronym on TunerPro. What is BPW and BPWC and how and why will I need to modify it?

Here is what I see

BPW Constant for EGR Off (Scalar)
BPW Constant Multiplier vs Barometric (table)
BPW for EGR On (table)

(FYI - I have three EFI tuning books coming from the library to try and learn)

[kscarguy]

Am I am right or way off on this...

BPW - Base Pulse Width. This appears to value based upon the result of a long mathematical formula. (BPW = BPC * MAP * T * A/F * VE * BVC * BLM * DFCO * DE * CLT * TBM) I can understand increasing the pulse width the let a little more fuel in to feed the 400. Now how? It seems like it would be in the BPW Constant Multiplier table...perhaps offsetting the entire 5.7 engine table by multiplying by 1.16? (406/350=1.16)

This raises questions to this newb...how would I know if this was too rich? Should I take it in small steps , say multiply by 1.5, then 1.8, etc? Is there something I should watch to determine if I am operating safely?

[lionelhutz]

Here is the info from Tunercat. I would just do the calculation and put the value in.

BPW Constant

Cylinder volume and injector flow rate are combined in this calibration value. A typical value for a 5.7 liter V8 is 135.
Cylinder volume is 5.7/8 or 0.7125L
Injector flow rate is 7.48 grams/sec, (61.22#/hr/injector)
Using the formula BPW = 1461.5 x (cyl vol / inj flow rate )
= 1461.5 x (0.7125/ 7.71 )
= 135
This constant should be changed if injector size or cylinder volume is changed.

[EagleMark]

After you calculate the correct BPW that's it, your done. It's not a tuning parameter. It is a calculation.

Way to go Newb! :thumbsup:

[Six_Shooter]

Although I've never found any formulas to be correct. I find I usually have to add about 20 to 30% to get a BPW that actually works without maxing the VE table.

[kscarguy]

I think I am getting this somewhat figured out...

Install fuel pump(s) buy don't get overboard on fuel pressure or flow since the TB regulator can get overwhelmed.
Install an adjustable regulator in the TB so I can change the pressure for WOT on the 406.
Check fuel pressure first before firing it up. Not to exceed 20 psi on supply line.

Since I have a 406 engine, my BPW will obviously vary because the cylinder volume is different. I will do the calculation of cylinder volume and locate the flow rates of bigger injectors. This will give me two different BPW values...one for each injector size.

WHERE do I change the values for the BPW? I only see these three locations: My guess is in the Constant Multiplier vs Barometric Table.

BPW Constant for EGR Off (Scalar)
BPW Constant Multiplier vs Barometric (table)
BPW for EGR On (table

Injectors? I read that the injectors should be sized to be between 10% and 90% duty cycle on the injector. My max RPM will be 6000 (If it can even rev that high with the small cam). How do I know where I am in the duty cycle of the injectors? How do I know which injectors will work better? At what point am I overworking the smaller 61 #/hr injectors?

EDIT

Did I do this right...? I did a SWAG guess on the HP to be 325...I could be way off.

325 HP x .50 BSFC (stock heads) = 162.5 # fuel per hour
162.5 / .85 duty cycle = 191.18 3 per hour
191.18 / 2 injectors = 95.6 # per hour per injector
SQ(95.6/81 BBC injector) x 13 psi for rated 81 injector = 18.1 psi fuel pressure

[kscarguy]

I re-ran the numbers and using a much lower 250 HP, along with the 61# injectors. I come up with a needed fuel pressure of 15.3 psi. This sounds far more reasonable for my mild engine mods.

I also ran the BPW formula above for the 406 vs. the 350 using the stock 61# injectors . I come up with a BPW of 156.6, or 16 percent higher than the 135 value used for a 350 engine. Before I try to start the 406 engine, should I modify the two tables (BPW with EGR Off) to a fixed value of 156.6 and (BPW With EGR On) high-lightening the entire table and applying a 1.16 multiplier to richen up the fuel mixture?

Past this, I am stumped as what to do.

[EagleMark]

Although I've never found any formulas to be correct.....I've got one and I'll attach it here, it's in Open Office format. But you'll see my final advice is to not use it...

18 PSI is about right for 325 HP. The Injector Duty Cycle is not something you can see until running and it's in Data log. Well it's in there because I changed some things in $42 so when you burn your first chip make sure you add "BPW and Spark Advance Hack" from the Patches folder. This will take out some useless data and put in useful data.

Are you running an EGR? Motors like this usually have them disabled, there's a Patch for that as well. Then the only Parameter that needs changed is "Base Pulse Width" in the fuel folder.

Now all that said I can tell you what I do... leave it alone and tune the VE tables. When you raise fuel pressure and do all the calculations you end up with a bigger (or smaller? I forget because I don't do this anymore) BPW and the bigger the BPW the lower the RPM where the engine goes from Sync fueling to Async fueling and Async fueling is about impossible to tune from BLM data from the Narrow Band O2 sensor.

Leave the BPW alone, raise the fuel pressure to 18 although if you calculate that it will say it's not enough, but it is when you data log and watch the Injector Duty Cycle because when these ECM go WOT and start to go static (100% IDC) they change from Sync Fueling to Async Fueling (and don't set the Async flag to tell you) and dump the fuel in, this is where you tune it by PE-AFR.

[kscarguy]

Thanks Mark for the PM on chip burning. I am very torn between learning to do this myself and paying a pro. I guess I need to do a little more investigating before I decide. It's not that I am afraid, it is a time constraint. I rent a house that is pre-sold and soon I will be given notice to move. I can't have my truck un-drivable for very long.

On that note...can I hook up an Ostrich 2.0 to my ECM and just run on that permanently? Does it require the solder in socket modification to the ECM? Can I do data-logging directly from it or do I go through the serial port on the .... (dang what's that anonym)...ALDL?

[Six_Shooter]

Yes, The Ostrich can be used as an EPROM replacement, however, IIRC you are using the '7747, which I have not had success using as an EPROM replacement with a '7747, even using the socket booster. I am sure there is a reason, and it's probably a pretty simple one, but I haven't needed to find why, so I just power it from teh laptop while I'm tuning, then program an EEPROM with the new BIN when I'm done.

[EagleMark]

So you have to load a bin to Ostrich everytime you loose key on power? Hmmm... that don't sound right, but I don't have one. My AutoProm will keep a bin loaded key off, no laptop overnight... but it's hooked up to ALDL... wonder if it's getting power from that?

[Six_Shooter]

The Autoprom doesn't seem to have this issue, I've read of a few other people having a similar issue with the '7747. No, the bin doesn't need to be re-loaded, just powered. It would be a simple fix to power the USB from a voltage regulator (based on a 7805) if need be, but it really hasn't been much of a concern, because the only '7747 vehicles I tune are not my own, so I don't leave the Ostrich in place. ;)

[kscarguy]

Here is the current plan...it seems the most logical and cost effective.

Install and wire everything, weld in an O2 port in my header collector, plug in the stock computer, get some kind of correct fuel pumps and a fuel pressure gauge hooked up, and finally, just see if it runs.

THEN...I will buy a data-logging cable to connect from the ALDL connecter to my USB port on my computer and perhaps an adjustable regulator if the fuel pressure seems too high or low. Use winALDL to download whatever numbers I can, and have Mark burn a chip for the 7747.

At some point in time, I would really like to learn how to reprogram the computer systems, but since it seems like that is something that can take years to learn, it seems best to leave it to the pro's so I can get this running quickly.

Am I making a good decision...?

[Six_Shooter]

Good decision, yes, best? Not sure...

There's no better way to learn to tune than to just start doing it.

You can read about it for years, but it won't really make sense until you actually make a change and see that change take effect. Then a lot of it just makes sense.

[kscarguy]

What are the odds the 406 will run on the stock 350 computer? If it runs good enough to drive, then I certainly wouldn't mind taking the time to learn, but if it runs really badly, then I will need a pro's help as time is not on my side. My real desire is to learn the newer systems so I can get into the LS engines and even the imports. The TBI seems like a good place to start.

[EagleMark]

It will probably run enough to drive around the block, but run very poorly at best! Get the fuel pressure up to 16 PSI or so and don't push it hard and no WOT runs.

When you buy a starter chip you do get a big learning curve by comparing it to an original and you'll see how many things change, it's a lot. Use the compare tool and difference tool in TunerPro RT to find how many then read the Comments and you have an advanced lesson on top of a starter chip. The when your recording data to make adjustments it's more lessons, hands one.

[kscarguy]

My fuel pump plan seems to be going down the toilet...I wanted to use the later model "Module" style in-tank pumps with the plastic cup built in. I have two pumps and planned to get aluminum bungs machined and welded to my tanks, the pumps would slide inside the bungs and a retainer ring on top would tighten the pump down on the O-ring. The issue is finding the right pump to fit correctly into the plastic housing and also have low pressure / low volume. After talking to the rep at airtec, it does not seem possible. The pumps with the double tubes on the bottom (for the correct fit) are all high pressure/high volume. He thought the low volume pump would most likely run the cup (reservoir) dry and perhaps cavatate. Well it seemed like a good idea.

[lionelhutz]

The pump can't run the module sump dry when the return goes back into the sump. A newer factory pump will move a fair bit of fuel but it should still work fine.

[kscarguy]

I quit. I give up. I am simply too tired and frustrated. This EFI swap is taking so much time and requiring so many modifications to an already heavily modified truck, that the project is not fun anymore.

I am going to stay with the carb for now and later, when the summer cruising season is over, I will return to the swap. For now, I think it is best for me to get it running and driving and to try and enjoy it. In the mean time I will try to figure out a decent and affordable fuel system.

I really hate admitting defeat...thanks for all the input.

[EagleMark]

Your just stressed for time, it's o fun when there is no time. You'll be back... to much desire! :rockon:

[kscarguy]

I might go forward with this swap after all, since I had to tear my engine apart for an exhaust valve leakage issue.

Which manifold is a better choice for a low rpm motor...the stock TBI intake or an Edlebrock performer with an adapter plate? Is there much of a difference?

[Six_Shooter]

There probably won't be a huge difference between the two, but knowing GM, they tend to design their engine systems to have a lot of torque just off idle, because it makes the vehicle feels faster and also helps the vehicle to get moving easier, without the need to rev the engine.

The nice thing about the intake manifold is that it's a fairly easy swap later on, if you feel the need to change.