Which Fuel Injection? [Archive]

TheSilverBuick

12-30-2011, 11:03 PM

TA I bet wouldn't have any problem upgrading an SPX. Who knows, maybe they'll give you the contact information of the guy that actually does the conversion. I just bought the SPX with fuel rails and injector bungs from TA, didn't get the whole kit. If you have the ability to weld aluminum and are a decent fabricator you could drill and weld your own. set up. I plan on doing a drill and epoxy injector bungs set up on a performer intake I have.

As for ECU, consider my two cents on the MegaSquirt for obvious reasons. I have around 35,000 miles on mine now. I could probably duplicate the system on my car for
~$700 intake (yikes! I think that's what I paid anyways)
~$250 MegaSquirt II (MS1 is $203, only thing is doesn't do is IAC control)
~$64+$85 Relay board plus relay board cable (optional)
~$67 Labeled made wiring harness.
~$59 Jimstim engine simulator (for assembly and testing)
~$400 8 42lb/hr injectors ($300 for 32lb/hr, which I ran until the aluminum heads and roller cam upgrade)
~$250 LC-1 Wideband O2
~$5.50 Tuning cable
~$65 Map sensor upgrade for second barometer,etc (optional)
~$467 for a squarebore 1,000cfm Edelbrock throttle body (there are cheaper single valve ones that will work, or a carb with a $15-$30 throttle position sensor tied to it)
$145 fuel pressure regulator.
~$110 Ford fuel pump (I ran one straight from the junkyard for a couple years, $30)
~$30 for coolant and air temp sensors new, need pigtails though (I just grabbed these from the junkyard with pig tails)
$30 in soldering iron and solder.
$30 in various electrical parts, connectors, etc.

Grand total $2,727.50 Prices have gone up a bit since I did mine =/ I originally didn't have $400 injectors and I didn't pay $110 for a fuel pump so I had around $2500 in mine, which I think is what I've been saying in any other EFI threads I've commented in. But this set up works for pretty much 100HP-650+HP, and will work well beyond that with a fuel pump and injector upgrade (and maybe throttle body?).

I'm going to call the fuel return line plumbing a push on cost as some kind of modification to the fuel system will likely have to be done for any system. But I only really have around 20 feet of 5/16th fuel line and a few miscellaneous plumbing parts added since I use the stock 3/8ths fuel line. On your car, I'd investigate using the 5/16th evap lines from the carbon canister (that's probably long gone?) as the return line. Be aware, there is supposed to be a restriction down to a pin hole size some where in that line, I think it's on the gas tank sending unit, but it could be in the line somewhere back by the gas tank. In retro-spect, I'd probably of used this line to simplify plumbing.

I'm not going to debate any other systems, just laying out there what I have. I want to do my Centurion on the cheap by using a performer intake and epoxy injector bungs, a Q-jet throttle body, possibly skip the relay board, and get the cost down by well over $1,000.

If you have any questions just ask, I'll be watching this thread :)

elagache

12-31-2011, 10:48 AM

Dear Dan and V-8 Buick members,

I am interested in switching from my 1050 holley style carb to fuel injection. there seems to be alot of choices.

Well there are some choices, but there aren't as many as it would seem. When I looked into this, the number of choices where someone had actually made it work on a Buick engine wasn't so large.

I see that T.A performance offers a type of fuel injection that requires me to send in my intake and install fuel rails.

I started looking at the TA Performance system too. But it is expensive and I didn't find anyone on V-8 Buick who had gone that route and offered a review. It is a lot of money to spend without some glowing testimonials.

I am also very interested in the F.A.S.T efi conversion kit. if i went in this direction do i still need the fuel rails that T.A performance offers? are there other choices that i need to consider?

Actually F.A.S.T as two product lines. The EZ-EFI system is a throttle-body unit, basically a replacement for your carburetor: http://www.fuelairspark.com/ezefi/default.asp. They also make a sequential EFI system: http://www.fuelairspark.com/Products/FS-%27EFI%20Kits%27-0.aspx but they only have kits for Chevy and Ford engines.

Because I'm having an engine built by Jim Weise in Minnesota but have to have it put on the car in California, I decided to go with the F.A.S.T. EZ-EFI system in part because of favorable reviews on this board like this: http://www.v8buick.com/showthread.php?t=181640.

If you can do more of the work yourself, systems like MegaSquirt will probably be less expensive and more satisfying because you'll have better control over the outcome.

It seems like this area is still evolving so you may find additional choices. However, you will find yourself having to be a pioneer of sorts.

Best of luck with your project!

Cheers, Edouard :beer

P.S. Definitely check out all the discussions on EFI in the High Tech for Old Iron (http://www.v8buick.com/forumdisplay.php?f=55) forum. This topic comes up periodically and you size up the "territory" very quickly by going over what has been already said.

wormwood

12-31-2011, 11:30 AM

Bizno... i am currently making 400HP at the wheels as dyno'd.

eleganche... i really dont want to be a pioneer simply because as i am prety good at bolting on parts, i am prety bad at diagnosing problems. i will look into the megasquirt.

silverbuick. i have an old SP intake, not an SPX, which i have had ceramicoated.

i guess i should state my goals with this possible upgrade. i would like to have a little better fuel economy , easier starting (as i have starting issues), and of corse a coolness factor.

satch

12-31-2011, 11:33 AM

I'm going the Megasquirt route....

@SilverBuick: what software do you use (Megatune, Megatunix...etc)? Do you plan to go to Megasquirt III for any of your cars? I have two Megasquirt I controllers I built six years ago, I just recently tested them and they work fine but unfortunately there's no upgrade path to the Megasquirt III for the early boards.

I'd go with the Megasquirt III if I was buying a kit today.

pmuller9

12-31-2011, 12:39 PM

Dan

There are 2 basic systems.

The Throttle Body Injection (TBI) is the easiest where you simply replace the carburetor with the TBI unit
and you control the fuel electronically and your present ignition system continues to control spark timing.

Then there is the port fuel injection which will require you to send the intake manifold to have injector bungs and fuel rail installed.
TA can do that service for you.
With this system you can still control fuel only or use the system to control spark also.

Depending on which port injection system you choose you can have the option of doing a distributorless "Coil On" configuration also.

Which route would you like to go and we can proceed form there

Paul

TheSilverBuick

12-31-2011, 01:44 PM

I am using EFIanalytic's TunerStudio.

I am running MS1/extra on my Thunderbird with a TBI, fuel only control.
I am running MS2/extra on my Skylark, fuel and spark.
Both are 3.0 boards.

In the works on the OHC Pontiac engine I'm going to run an MS3 for not just the sequential injection, but so I can balance the AFR's on the individual cylinders. Which will help the engine reach it's peak potential because port lengths and shapes vary the AFR's vary cylinder to cylinder in almost every enigne. MS3 allows a fuel trim for each cylinder. Only worth the cost IMO if you are looking for that last degree of HP. I have a 3.57 MS1 board that should be upgradable to MS3, or I'll use the 3.57 on the T-bird and convert a 3.0 board over.

If you aren't using an IAC (just use a simple high/low idle valve) then you can't be the value of an MS1.

Also if you have some wide band readings or know what your AFR's were at peak HP, it's easy to create an AFR table based on the dyno info and the EFI will match it.

wormwood

01-01-2012, 12:46 PM

Thaks Paul, that is the kind of info i need, but what are the pros and cons of each system?

elagache

01-01-2012, 05:15 PM

Dear Dan and V-8 Buick high-tech gurus,

Thaks Paul, that is the kind of info i need, but what are the pros and cons of each system?

Well, if you are going to ask . . . . . you are likely to be sorry!! :Do No:

There is another fork in the road before comparing throttle body versus sequential fuel injection. There is two different ways to determine the air-fuel mixture. By far the most common technique is called "Speed-Density" This technique computes the amount of air going into your engine from various parameters like engine speed and manifold vacuum pressure. This is a fairly precise calculation but . . . (remember the devil in the details?) It requires some adjustment of lookup tables to make everything work out correctly. This can be done by a human - precise but tedious, or by software - easy but obviously less precise.

One of the main arguments for a system like EZ-EFI is that it is self-tuning. However, the price you pay is that the self-tuning may not make the best use of your car's potential.

Other systems such as the Megasquirt family and Accel EFI allow the user to tune the engine manually using a laptop or equivalent. The very advantage is also the curse. You have more control but . . . you have more control to make mistakes in. :grin: Obviously, if the software you are using is "smarter" mistakes are less frequent. However, experience around V-8 Buick suggests that you need to get a "feel" for the process. If this sort of thing feels like exactly the sort of tinkering you'd enjoy then you have a new potential hobby. If not - you've got problems. If money is no object, then having a professional tuner and station will most likely get more out of your engine than any amount of your amateurish tinkering will get you. One theme reported on V-8 Buick is that if you tinker too much you'll make things worse and - how you know when you've tinkered "just enough"?

Back at the beginning of this post was the other fork in the road. Mass Flow systems. In this case sensors actually measure the amount of air mass flowing into the EFI system. This in principle should eliminate a lot of the guesswork. Sadly the only system on the market is produced by a company called (surprise) Mass-Flo: http://www.massfloefi.com/. However, this company is using some very dated electronics and I couldn't find anybody who has used their product on a big-block Buick engine. So I gave up on these guys - basically because I needed a safe choice in a complex predicament.

There is a slanted article toward Mass Flow systems here: http://www.carcraft.com/techarticles/electronic_fuel_injection/index.html. Still, it may help you understand some of the concepts and make sense of the EFI vocabulary.

Or, after reading all this . . . you might decide a carb isn't so bad after all!! :laugh:

Best of luck . .. . it t'aint easy!!

Cheers, Edouard :beer

TheSilverBuick

01-01-2012, 09:34 PM

Pretty much they all get fuel into the engine at least as well as the carb and all are capable of more consistent starting and keeping in tune than a carb, some have timing control abilities, some do not. Some have upper horsepower limits, just watch for that. Then some are bolt on and go and others are more hands on.

Like Mark says, if you can get your hands on the tuning software for various ones, you can check out how all the user settings are laid out and like Edouard says, more control can mean more places to screw up a setting, but it's really no different than how many settings can be screwed up on a carb (for proof look at the mixing shop board =P ) only you don't have to spill gas everywhere to change the settings!

71stagegs

01-01-2012, 09:45 PM

Dan Look at this, looks too easy?
http://www.atomicefi.com/AtomicInstallationVideo.aspx

pmuller9

01-02-2012, 03:14 AM

Thaks Paul, that is the kind of info i need, but what are the pros and cons of each system?

Dan

To start with, any EFI system (TBI or MultiPort) will require a high pressure fuel pump at or in the fuel tank.
In the tank is preferred because the fuel helps keep the pump cool for longer life.
Base or minimum pressure is 43 PSI at the injectors for proper operation.

The TBI is the easiest and cheapest to install because it simply replaces the carburetor.
The down side, as stated in some of the above posts, is most models have limited programmability and most models do not control spark.

MultiPort Fuel Injection:

With MPFI the sky is the limit especially if you are an outside the box thinker.
As you can tell from the previous posts, one of the deciding factors is your willingness to experiment and learn the technology.
If you are comfortable with a laptop and want to have fun then go for it.

Most of the systems can be examined online by downloading their software and the installation instructions.
This way you can get a feel for the system and also see if it has all the features and controls you need.
It's also important if there is a tech available (Like Mark) that can give you a kick start and be readily available to help.

The main advantage is the ability to control both fuel and spark based on all engine parameters including knock
and the ability to control many of the things external to the engine such as transmission, radiator fans ect.

In sequential mode individual cylinder tuning can be done.

There is the option to go distributorless or "Coil On" which gets rid of distributor phasing problems especially for wide swing timing when turbocharging.

For spark control it is far easier to make a change in the spark table than to recurve a distributor.
This will let you experiment with timing all day with just the touch of the keyboard.
The software will also show you real time, exactly what number from the table it is presently using so you know where to make changes
on both the fuel and spark tables.

Then there is the list of controls specific to power adders and racing and the list goes on. You get the picture.

The other reason for the advent of MPFI is to remove the restriction on intake manifold design where the intake runners have to converge where the carburetor is located.
Now better designs could be incorporated and still be packaged under a hood.
This gives the DIY guy a chance to create a wild design for the WOW factor or do something like Velocity Stacks for show.

If you do 2 injectors per port you can run a dual fuel system with pump gas in one and race gas in the other.
When running a turbo or supercharger the system will automatically switch from pump to racing gas as the boost exceeds the limit for pump gas octane.

Anyway this is just the tip and you can get as creative as you want.
In our shop we do not use carburetors!

The down side is it cost more.
In post #3 TheSilverBuick took the time to list one of the least expensive setups.

As always I hope this helps

Paul

P.S. Which Gibson cam are you using? The 107 or the 110

Nothingface5384

01-02-2012, 09:43 AM

That's why Accel introduced the Thruster. For lack of a better term they "dumbed" down the Gen 7, however most all the features of the Gen 7 are still accessible with the Thruster box, you just use the Gen 7 software instead.
But one thing to remember, a lot of those screens don't need to be fooled with, hence the lack of accessibility on the Thruster. But on the flipside they're in there in the event you do need them and can add tremendous improvements in drivability vs something that doesn't have them.
And when I sell a system I sell it with a base program and help. I do alot via the internet, I can change calibrations and email the changes back to you to download into the ECM. You can't do that with all of them.

does the thruster work with blowthrough...or need any blowthrough modsbto the throttlebody

pmuller9

01-02-2012, 11:21 AM

does the thruster work with blowthrough...or need any blowthrough modsbto the throttlebody

The Thruster supports up to 40 psi of boost and it is just a matter of selecting the right Map sensor.
If you are doing 15 psi or less you will need a 2 Bar Map sensor.

You will also need to use a boost referenced fuel pressure regulator with the system.

Mark can verify and give more info.

Paul

Nothingface5384

01-02-2012, 12:06 PM

The Thruster supports up to 40 psi of boost and it is just a matter of selecting the right Map sensor.
If you are doing 15 psi or less you will need a 2 Bar Map sensor.

You will also need to use a boost referenced fuel pressure regulator with the system.

Mark can verify

Paul

yea, I knew about the needed xbar map sensors which dictates the amount of supported boost..the only system I knew of that supports blow through out the box was the powerjection3 with a map sensor.others like holley or fast need modifications to the throttlebody itself along with the Xbar map sensor

elagache

01-02-2012, 04:52 PM

Hi Paul, Dan, and V-8 Buick high-tech gurus,

First, Thanks Paul for explaining the difference between throttle-bodies and MultiPort fuel injection. That was Dan's actual question, but . . . by the time I had explained everything else - I forgot!! :Do No:

Second, I'm realizing that I have some nagging misconceptions that others might be having as well. So, just in case I'll toss them out.

All MultiPort fuel injection systems have injectors in the intake manifold. However, a Sequential MultiPort fuel injection system goes one step further by only injecting into a cylinder that is about open the intake valve - correct? This requires some sort of a timing device like the ACCEL triggering distributor - right?

Assuming I got this much right, I'm confused by the term: "tuned port fuel injection." Does "tuned port" refer to some sort specific modifications to the intake manifold that somehow "tunes" the airflow with the injection, or does this refer to modifications in the cylinder head itself?

Wikipedia doesn't discuss this - can't trust anybody these days!! :laugh: and Google generates some very puzzling hits. I fear manufacturers are misusing the term as well.

As along as I'm dumping my confusions, what is "gasoline direct injection?" Does that involve a new opening into the cylinder combustion chamber? The Wikipedia article mentions some interesting economy and emission advantages: http://en.wikipedia.org/wiki/Gasoline_direct_injection.

Okay, so I've tossed out my confusions . . . :Do No: Can somebody Learn me about all this!! :Smarty:

Thanks in advance!! :TU:

Cheers, Edouard :beer

wormwood

01-03-2012, 12:59 PM

Paul... The Gibson 110

Thanks for all the input fellas. after reading all of this, i'm thinking i just dont drive the car enough to put this kind of effort and money into it. i am interested most in the multi port as described by paul. so is that the one with the fuel rails that TA offers? please pardon my ignorance.

i think i will put my time and effort in figuring out why my car has such a difficult time starting, and not just band-aid it with fuel injection. maybe ill save it for another day. (like if my tax refund is more then expected)

TheSilverBuick

01-03-2012, 08:08 PM

TA is the only one that offers a Buick intake out the door with injector bungs and fuel rails. I'm sure they can work with you on getting the intake, injectors and fuel pressure regulator then you can just wire in your choice of ECU.

Hey, I fired up my q-jetted and points powered Centurion today and after the initial cranking (hasn't been started in a couple weeks), it re-fires up quicker than "any" EFI system I've seen, OEM or otherwise. It's not impossible to dial in a carb and distributor, but they can be as confusing as EFI, lol!

TheSilverBuick

01-04-2012, 08:28 PM

Or I have a superbly tuned Q-jet and points set up. Instantaneous fire up, as quickly as you can turn the key. No waiting for the fuel rail to pressure up, no waiting for the timing signal to sync. Call it what you will, it starts quicker than any OEM new car I've ever started in the last 15 years.

bammax

01-06-2012, 11:52 AM

Basically this is the breakdown.

Carb: dumps fuel and air into the engine in a lump based on the throttle position which moves valves and levers mechanically.

TBI (throttle body injection): dumps fuel and air into the engine in a more atomized lump based on the throttle position and a few sensors and which open valves electically.

Batch-fire Multiport Injection: Squirts fuel into each cylinder directly by way of an injector positioned in the intake track just above the intake valve. It's controlled the same way as the TBI but with more sensors. This system fires every injector at the same time regardless of which cylinder needs the fuel. Some such as the F/Y-body TPI (tuned port injection) also have an "upstream" injector which fires fuel into the intake when cold to richen the mixture and allow the engine to warm up faster. The vortec 4.3 in the mid 90's used a "spider" located under the intake to distribute the fuel from the line to the cylinders via plastic tubing and poppet valves.

Sequential Multiport Injection: Mechanically the same as the batch-fire above, but with better control. This system fires fuel to the specific cylinder that needs it just before the valve opens fully to ensure no fuel is wasted in cylinders that aren't burning. It's main difference from batch fire setups is that it uses both a crank and cam sensor to know which cylinder is on the compression stroke during the intake opening sequence.

Fuel injection can also be broken down into speed density and Mass Air Flow systems. Speed density uses a graph and dumps a certain amount of fuel based on your rpms. It's downfall is that the graph must be perfect and the engine may still have issues if you change altitude or the air temp changes. Mass Air Flow measures the amount of air moving into the engine as well as its temp to determin the proper amount of fuel needed to maintain the proper mixture. It's downfall is the added sensors such as the MAF, IAT, and O2 which can be avoided somewhat with speed density.

TheSilverBuick

01-06-2012, 09:30 PM

I understand you're trying to generalize EFI but imo you gave less than accurate and misleading info.

I kinda have to agree. Bammax mostly described an Alpha-N system for speed density. Alpha-N uses only rpm and throttle position for sensors (practically mechanical injection, but electronic). Speed density requires** the whole suite of sensors (cam sensor optional for sequential), and you build a fuel table off rpm and engine load (vacuum/atmospheric pressure) and uses the suite of sensor to calculate air density, where as a MAF system uses a heated element and calibrated tube diameter (the MAF sensor) to calculate the mass of air passing through) and the suite of sensors to trim the fuel calculations.

**I use 'requires' loosely in the sense if one or two sensors fail the system won't quit, just not operate optimally.

doc

01-08-2012, 06:51 AM

doc

01-08-2012, 12:01 PM

Actually,, I used a 89 jeep set up,,,, from a wrecked comanche,,,, tuned it up several times,,, replaced all the injectors.... with brand new ones,,,, and I am a certified mechanic.... efi just did not do that much for that particular vehicle...

pmuller9

01-08-2012, 01:04 PM

Every component in any system is a potential trouble source.... the power will not be that much different, the economy will not be that much different,,, the expense and the hassle will be way more.... for 2700 bucks you can pretty well install a huffer..... and that would boost both the mileage and the power .... I converted a jeep to efi and after 5 years of hassle finally took it back to a holley carb.... it ran better with a carb with way less hassle....... IMHO,,,, mistake,,,,

Doc

You were correct when you said that going a factory EFI system or any system that does not allow the user to tune the fuel or the spark tables can be a Mistake.
That was the very point at the begininng of this thread that systems that allow the user to have full control
have the advantage over systems with limited or no access to the control unit.

It was also pointed out that systems with full access give the user the most flexibility for success as well as the most freedom to screw it up.
So it depends on how much support comes with each system and how much a person is willing to take on.

Also there are many variables in going to a "Huffer" that can make the project a success or a frustrating situation also.
If a person wants a supercharger system that doesn't violate the hood, then in most cases we are back to EFI again.

Anyway this thread was successful because it gave Dan (the one who started this inquiry) the information he needed to make an educated decision

BTW I love supercharging for street use!

Paul

doc

01-08-2012, 04:00 PM

Dead on,,, Paul,,, :Smarty: Goes back to my statement about adding more components makes for more opportunity for failure of some kind....:laugh: :laugh:
In my case,,, the truck was a 81 and the efi was the stock set up for 89 and still pretty primitive.... not laptop tunable....
In my humble,,,,:Brow: simple is better...

TheSilverBuick

01-08-2012, 04:32 PM

Yup, carbs are simple.

http://www.v8buick.com/forumdisplay.php?f=83

bammax

01-09-2012, 01:47 PM

I was going with a generalized breakdown since it makes it a bit easier to undertsand the fundemental differences. If you get too specific than it becomes way too confusing to someone just starting out. For example I left out the double injectors per cylinder for nitrous setups, and the Bosch analog injection on the Olds motors in the late 70's, or the mechanical fuel injection from the 60's. For the most part speed density comes down to a fuel map that doesn't fluctuate while maf systems have a little more on the fly variability to the enrichment.

Remember that this will come up years later on a google search so don't make things too specific and leave out the non-engineers :pp

TheSilverBuick

01-09-2012, 09:17 PM

I won't get into a pissin match here but that's simply not true.

I concur on both accounts.

TheSilverBuick

01-10-2012, 09:15 AM

Where I simply can drive from 7500+ feet in elevation to sea level on a single trip. And as the year progresses drive in conditions with air temps less than -10*F to greater than 120*F. Huge variations in atmospheric running conditions. That's my main motivation. I can get a Q-jet to start and run great at each of those, but I'd have to break the screw driver out everytime I drive off this mountain because my idle goes up 300+ rpm, plus it has off the line hesitations if tuned for one elevation and driven in another. Not to mention choke settings in winter versus summer. I've finally become complacent enough with the EFI I can now "Set it and forget it" and it's good. :TU:

bammax

01-10-2012, 10:27 AM

I won't get into a pissin match here but that's simply not true.

So say what the difference is then? The point of this thread is to help people understand but all you're doing is harping on me about the exacts of outdated technology. Either give us the actual explination as to the differences between speed density and maf and why the oems ditched speed density or find a new target to sling crap at.

I'm basing everything I say off of the findings of someone using junkyard GM parts in a retrofit. The most common speed density system someone will come across is the 80's f-body. It's great in hot rods but there's a reason why it was dropped prom production cars fairly quickly.

Here's a great writeup explaining what each does and how it works. It also shows what years they were used. It's a great starting off point when going junkyard hunting for efi parts from GM's
http://www.carcraft.com/techarticles/electronic_fuel_injection/index.html

TheSilverBuick

01-10-2012, 10:49 AM

From what I gather, OEM's went to the MAF system (that actually works in conjunction with the speed density system, MAP sensors are still on new cars) primarily for pre-warmed up conditions. Before the O2 sensors fired up, and to get a better grasp on air density before heat sinking under the hood took place. The MAF sensor helps calibrate the computer on knowing how much oxygen is in the engine and can back check against what the speed density system is calculating based on air intake temperature and engine vacuum(compared to atmospheric). OEM's are under government pressure to make sure emissions are met, so it's in effect a redundant system, if one doesn't agree with the other then you get a check engine light but the car doesn't quit running (anymore..). The MAF sensor can help back check the calibration on the baro table as like the O2 sensor can do feed back for atmospheric condition changes, where as a strictly Speed Density system with no O2 feedback turned on or second baro sensor (and calibrated table) can go astray. Most aftermarket speed density systems utilize an O2 feedback, some utilize a second baro sensor and table, and some both.

The aftermarket embraces the speed density system most often because it's so flexible. A speed density system doesn't care if it's on a 100cc engine making 2HP or on a 5,000HP big block. Simply upgrade the fuel system and throttle body and go. A MAF system is limited by the MAF's available. Can you find a MAF for a 2HP engine? You could probably successfully use one from a small car, but if you upgrade to even 800HP, or more, how many MAF's are available and at what cost compared to a simple throttle body? They are rarely as upgradeable as projects progress because of their physical limitations, so only a few aftermarket companies go that route. If you can build a product that fits 300 applications, or build a product that can fit those 300 applications plus another 700, which route would you go? Economically the one that has the broadest reach.

As mentioned, if you can not adjust the system on an aftermarket setup, then it sucks, no matter what type.

bammax

01-10-2012, 11:13 AM

Now that's some good info.

One thing to keep in mind too is that aftermarket mafs have a habit of producing poor performance on some cars since the maf isn't the same calibration as what the ecm is expecting to see. It's common on the LT1's to have a car become unreliable when the maf is swapped out for the bigger aftermarket unit.

One common between all systems though is the need for a good temp sensor. On the TPI cars a bad temp sensor causes the upstream injector to stick on and it kills mileage. On the LT1 cars a bad temp sensor causes the entire car to go haywire. On the old Bosch analog units the temp sensor going bad would cause a no start condition.

TheSilverBuick

01-10-2012, 12:39 PM

With a laptop it's a walk in the park to troubleshoot issues like that. Due to my shoddy wiring I was having an intermitted break in my air intake temperature sensor readings. It manifested itself as a bucking while driving down the highway, plugged in the laptop and instantly saw my IAT bouncing radically causing a lean condition (on an already pretty lean cruise tune!). I ignored it for the rest of the trip and tracked down the wiring issue when I got home (150 miles later), no real problem. Worse case scenerio I could of unplugged the sensor and made a temporary change to the VE table to account for the default air intake reading. Yes I needed my laptop, but A) I didn't stop and actually do anything about it until I got home so I was never stranded and B) sensors rarely fail, this was an installation failure, aka operator error. I have 35,000 miles on my MegaSquirt and it has yet to leave me stranded anywhere, this instant mentioned actually is the only issue I recall having.

bammax

01-10-2012, 06:44 PM

More good info from you guys. That's the stuff we need to help determine how to choose a system for a retrofit.

I'm personally looking at using a factory LSx system powered by the eficonnections 24x setup. The tricky part is trying to get the crank and cam sensors installed correctly. I'm figuring on using the cam sensor from the vortec van motors adapted to a stock Buick distributor body. The 24x system provides the cranck sensor, but it's going to be tricky trying to figure out the install since it can't be put in the stock timing cover like in the Chevy motors. It'll probably be done externally the way it was in another one of SilverBuicks posts.

The programming trick will be getting the fuel output in the LSx computer rich enough to keep up with a 455. I may have to use the mapping from a Vortec 454 as the base and adjust from there.

TheSilverBuick

01-10-2012, 08:07 PM

I think you're going to be surprised how different those 2 fuel curves will be (LSx vs your 455). I think you'll have to retune the whole thing.

Jmo.

Agreed, the BSFC on the LSx engine is probably waaay better than a BBB, and not just at peak power. And you may of noted, mine is a 36-1 wheel.

I do things mostly as cheaply as possible to get what I want done (because cheap is the Q-jet and base distributor =P ). I'm thinking of adding a Grand National cam sensor and a set of LS coil backs to go distributorless. Just need to cough up the dough for the coil packs :idea2: I still have no desire to go sequential on my Buick engine as I don't plan on putting in the necessary dyno time and individual AFR monitoring required to take real advantage of it. The coils are for athsetic's and uniqueness on a BBB.

TheSilverBuick

01-11-2012, 08:28 AM

Don't really need the dyno time, you've been mislead there a bit.

If when in sequential you can adjust injector timing, then it's not hard to get really close to optimum without a dyno.
While at different loads and speeds, watch your O2 feedback. As you change injector timing and get closer to optimum it will need to remove more and more fuel based on your current fuel map. And when it's right you'll notice it will need less transient fuel, you've just made it more efficient. That will be the biggest change.
Just like in the old days when you timed cars by ear, the fastest idle etc was the most efficient.

Hope this helps.

Oh for sure, you can definitely hear when the engine is happiest, almost like they sing. Datalog wise, like the old days, watch for peaks in vacuum too. And that'll work with the injector timing (relative to the valve events), but I was refering more to balancing the cylinder to cylinder AFR's. The testing one of my friends has been doing on 8 cylinder AFR monitoring (look at the current EMC Hemi article) on a couple different types of engines, they all have about a 1 full point of difference between the leanest and richest cylinder, so you are really tuning the whole engine to the leanest cylinder if you don't want detonation or such damage. That's the part I'm referring too. Both sets of adjustments really only get you that last few percent of HP (about ~30HP on a 1,000+HP n/a engine). *Also, not all sequential EFI systems have the capability to do individual cylinder fuel (and spark) trim.

If some one wants to loan me a set of Buick headers with 8 O2 bungs in I'll be glad to borrow them though :laugh:

bammax

01-11-2012, 07:54 PM

If you're going for reliability and ease of use then there's not much need to do the per cylinder fuel adjustment. In a perfect world it would happen, but it's not hugely important unless you're trying to squeeze out every drop of power or efficiency. A multipoint system should get your cylinders closer to balanced than a carb just by the design of the fuel path.

Also as I noted at the end of my last post, I'm probably going to start with the Vortec 454 tune and work from there. That motor is far more efficient so right from the junkyard it'll probably be running a bit lean. I figure reduced timing and slightly higher fuel pressure should compensate long enough to get the tune right.

Seems you're about 2 years ahead of my on this junkyard FI stuff.