EFI benefits with Carb appearance?

maxxfish · Aug 10, 2005

EFI benefits with Vintage looks?

Hy everyone,

I just found this forum, and this is my first post. Looks like a great resource!

I just bought my first Mustang, a '69 Mach 1. The original FMX is with the car, but no motor. As part of the deal I got a 351W and a C-4 which were pulled from a '75 truck, and I would think they need rebuilding.

If I have to go to the trouble and expense of rebuilding, I should probably change this up a bit. I see a T-5 or AOD in the future. I thought about a 5.0 EFI swap, but it would be a shame to put that in a Mach 1. I just don't think the EFI intake would look right.

So after some research, I discovered the Edelbrock RPM EFI setup. Looks relatively stock, but has all the benefits of EFI. Seems to be plug-and-play, simple setup. But its $2600. So should I rebuild the 351W and get this?

There is also a Holley EFI setup that takes the place of a carb, but isn't really a complete system (although it's $1500 less).

Or how about a full 5.0/T.5 swap...is there any way to make this setup look 'vintage?' Yes, I know about the 4-weber EFI setup: it's a fortune! Other options? Advice? Estimated costs? Also, how much $$$ am I looking at for a 351W rebuild? Thanks in advance,and looking forward to being on the forum! Max

ForceFed70 · Aug 10, 2005

For closest to carb appearance, you'd want to go with a Throttle Body Injection method.

Holley makes a complete system:
http://www.holley.com/products.asp?product=950-22S

This setup is nice because it's pretty much the same thing as doing a carb swap, except you have to add a ECU, O2 sensor, and coolant temp sensor.

I'm going to go this route in the winter, except I'm going to assemble my own system. I plan on using a 4bbl throttle body like the holley system, except I want to use a different ECU (megasquirt).

SitDown · Aug 10, 2005

To keep the same look you can run a efi spyder intake and accufab makes 2 lines of EFI 4 barrel TB's...

their 4150 unit is around $500(4500series ~$600), seems pricey but youd spend the same on a decent carb adn ~$300 ona standard tb&egr

68rustang · Aug 10, 2005

It's pricey but a better overall system than the ones already mentioned which are speed density systems.

http://www.mass-floefi.com/

It is a mass air system just like the 89 and up 5.0s

Bullitt · Aug 10, 2005

if you are interested in doing this (for a 289/302), i have both a 4 barrel TB like SitDown posted a picture of and an Accel intake manifold (Victor Jr style with machined injector pockets and billet fuel rails) for sale.

PM me if you're interested.

ForceFed70 · Aug 10, 2005

68rustang said:
It's pricey but a better overall system than the ones already mentioned which are speed density systems.

http://www.mass-floefi.com/

It is a mass air system just like the 89 and up 5.0s

Just because they say mass air is better, doesn't mean you should believe them

When it comes down to pure performance, speed density is infact the better system. However it does have some drawbacks. It really depends on the application and the owner.

68rustang · Aug 10, 2005

70_Nitrous_Eater said:
Just because they say mass air is better, doesn't mean you should believe them

Just because they say mass air is better, doesn't mean you shouldn't believe them.

For a race car, or tuning for specific conditions yes speed density is better. For someone who drives their car in varying conditions (altitudes, temperatures, fuel, etc) or is continually making small upgrades (headers, cat-back, different intake, etc) as most of us are, The mass air system is better because of its ability to adapt. My bike, an SV650S is fuel injected with a speed density type system. If I go too far past what the default tables in the computer can handle mod wise, I have to reprogram the computer. When I say too far I currently have a slip on pipe on it, if I would even add something as small as K&N filter I would need to re-map the fuel curves or it would run too lean.

65up2d8 · Aug 10, 2005

68rustang said:
Just because they say mass air is better, doesn't mean you shouldn't believe them.

For a race car, or tuning for specific conditions yes speed density is better. For someone who drives their car in varying conditions (altitudes, temperatures, fuel, etc) or is continually making small upgrades (headers, cat-back, different intake, etc) as most of us are, The mass air system is better because of its ability to adapt. My bike, an SV650S is fuel injected with a speed density type system. If I go too far past what the default tables in the computer can handle mod wise, I have to reprogram the computer. When I say too far I currently have a slip on pipe on it, if I would even add something as small as K&N filter I would need to re-map the fuel curves or it would run too lean.

You hit the nail on the freakin' head.

ForceFed70 · Aug 10, 2005

68rustang said:
Just because they say mass air is better, doesn't mean you shouldn't believe them.

For a race car, or tuning for specific conditions yes speed density is better. For someone who drives their car in varying conditions (altitudes, temperatures, fuel, etc) or is continually making small upgrades (headers, cat-back, different intake, etc) as most of us are, The mass air system is better because of its ability to adapt. My bike, an SV650S is fuel injected with a speed density type system. If I go too far past what the default tables in the computer can handle mod wise, I have to reprogram the computer. When I say too far I currently have a slip on pipe on it, if I would even add something as small as K&N filter I would need to re-map the fuel curves or it would run too lean.

Speed density will also adapt to changes in air temp, altitudes, and different fuels. Just as well as mass air will at least.

Have you ever ran a speed density system? Something as small as a filter change will not effect performance. Speed density systems also have an O2 sensor don't forget.

You only need to reprogram for large changes. And to be 100% honest, when you get into serious mods on a mass air system, you should be reprograming your ECU also.

The only disadvantage to speed density is that you need to reprogram for large engine changes. And I mean large changes, not filters or anything minor. Go with a programmable ECU and all it costs you is a little time. Personally, I won't mind spending a few hours programming and datalogging the once a year I make a significant engine change. Especially considering the benifits I'll get in return for using Speed density in the 1st place.

67coupestang · Aug 11, 2005

i ran a SD system on my 76 bronco for a while and i flipped between a stock 60?mm throttle body and a larger one and the car ran sugnificantly better with the 60. better throttle response anyways. Just what i observed....

68rustang · Aug 11, 2005

70_Nitrous_Eater said:
The only disadvantage to speed density is that you need to reprogram for large engine changes. And I mean large changes, not filters or anything minor...

Maybe not a filter itself but a filter in combination with all or many other bolt on mods that we often add as we get the money can cause a significant change in the engine's air requirements. The SD system doesn't know exactly how much air is going into the engine. It can guess based on what is coming out of the tailpipe, TPS, temperature, pressure, etc but it still doesn't know for sure. The MAF system DIRECTLY measures the amount of incoming air along with all the other afore mentioned variables and then some. With MAF you can modify to the point of exceeding the limits of the stock fuel tables but this can be compensated for by swapping injectors and recalibrated MAF meter. Each system has its plusses and minuses which can be discussed until the cows come home. IMHO if you are going to be spending money on an EFI system the stock ford MAF EFI is a better system that the aftermarket SD or more primitive systems. Not to mention parts availabilty.

rufusbooth · Aug 11, 2005

"IMHO if you are going to be spending money on an EFI system the stock ford MAF EFI is a better system that the aftermarket SD or more primitive systems. Not to mention parts availabilty."

Ahhh. The miss informed.

68rustang · Aug 11, 2005

rufusbooth said:
Ahhh. The miss informed.

Okay, where is the misinformation?

68rustang · Aug 11, 2005

I did some more reading after googling "ford speed density vs mass air." I don't see where I am misinformed. MAF is a better system for street cars, mild performance engines, varying conditions, mod as you can, most of us kind of cars. SD is a better system for high performance, specific you really know what you are doing conditions. SD can supposedly handle higher horsepower IF programmed correctly.

ForceFed70 · Aug 11, 2005

68rustang said:
Maybe not a filter itself but a filter in combination with all or many other bolt on mods that we often add as we get the money can cause a significant change in the engine's air requirements. The SD system doesn't know exactly how much air is going into the engine. It can guess based on what is coming out of the tailpipe, TPS, temperature, pressure, etc but it still doesn't know for sure. The MAF system DIRECTLY measures the amount of incoming air along with all the other afore mentioned variables and then some. With MAF you can modify to the point of exceeding the limits of the stock fuel tables but this can be compensated for by swapping injectors and recalibrated MAF meter. Each system has its plusses and minuses which can be discussed until the cows come home. IMHO if you are going to be spending money on an EFI system the stock ford MAF EFI is a better system that the aftermarket SD or more primitive systems. Not to mention parts availabilty.

No offense, but I'm wondering if you really know how both fuel injection systems work? Speed Density also measures the air coming into the system, it just does it a different way.

Speed density uses a MAP (manifold absolute pressure) sensor. It measures vacum in your intake manifold and calculates the fuel requirement based on the volumetric efficiency of your engine, RPM, and a default fuel map. It then uses the other sensor inputs to adjust the fuel injected (ie O2 sensor, coolant temp sensor, intake air temp sensor, throttle position sensor, etc). This is where you run into problems with large engine mods, as you end up changing the volumetric efficiency of your engine. However, the other sensors will still offer feedback and thus small changes do not effect performance.

Mass air does have some advantages. Mostly in the fact that it's a more direct way of measuring air, and thus adapts to engine changes better. It's also a little simpler to understand...

Speed density has advantages in that because there is no device measuring airflow, there is less restriction to airflow (more power). Also, mass air measures airflow by using a heated wire.. which in turn heats the air entering the engine(less power). Also this heated wire is prone to failure, and is a costly device. Mass air meters usually go for around $200 and need to be calibrated. MAP sensors cost $30 and do not need to be calibrated.

In some examples, speed density can be the more robust system. For example.. in a mass air vehicle, a vacum leak causes major greif. Simply because unmetered air is entering the manifold. With speed density all that happens is your engine idles too high.

It depends on the application and owner... but speed density does have some real advantages, and a blanket statement like "mass air is better" is not applicable. No more than saying "trucks are better than cars".

68rustang · Aug 11, 2005

70_Nitrous_Eater said:
No offense, but I'm wondering if you really know how both fuel injection systems work? Speed Density also measures the air coming into the system, it just does it a different way.

No offense taken. I fully understand how both systems work. I have read the Ford fuel injection book by Probst and everything I can get my hands or computer mouse on. I don't think this is the place to nail down every little minute detail of both systems. It has been done before by people more qualified than you or me.

Answer me this, how will a SD computer compensate for changes in VE (volumetric efficiency)? Does the SD computer know precisely how much air is moving through the engine? No. Does it have a pretty good idea? yes. MAF measure the air intake DIRECTLY. Yes the little tube causes some restriction and turbulance but like I said each has it's ups and downs. www.fordfuelinjection.com has nice chart showing the plusses and minuses of both. Each has it's place, IMHO MAF is a better system for what I and most others are doing.

ForceFed70 · Aug 11, 2005

68rustang said:
Answer me this, how will a SD computer compensate for changes in VE (volumetric efficiency)? Does the SD computer know precisely how much air is moving through the engine? No. Does it have a pretty good idea? yes. MAF measure the air intake DIRECTLY. Yes the little tube causes some restriction and turbulance but like I said each has it's ups and downs. www.fordfuelinjection.com has nice chart showing the plusses and minuses of both. Each has it's place, IMHO MAF is a better system for what I and most others are doing.

Hey I already agreed with you that mass air does a more direct measurement of air. The only thing I've disagreed with you on is your statement that one system is better than the other. Speed density does use EGO correction and will thus "adjust" to changes of VE within a small range.

Mass air is not the best system for me... and I bet alot of others on this board.
For those of us who are budget minded, want the absolute best performance and don't mind spending a little time tuning...then speed density IS the BEST system.

Tuning really isn't that difficult with the right tools. Easier than tuning a carb IMHO.

ADub64 · Aug 11, 2005

Just to throw in another perspective. A lot of the LS1 performance guys are chunking their MAF and converting to speed density. This is because the speed density tuning capabilities have developed leaps and bounds over what they were in 1986 when GM and Ford starting using it. The speed density actually performs more favorably with a heavily modified engine. Either way, once you get to a certain point, significant tuning is required either way you go. Yes, the MAF does create another restriction in your intake, but do you really think that wire generates enough heat to make an appreciable difference in intake temps? I have to disagree there.

AW

68rustang · Aug 11, 2005

Tuning really isn't that difficult with the right tools. Easier than tuning a carb.

Coming from the "computer generation" myself I couldn't agree with you more.

cougar_68 · Aug 11, 2005

Hey, this is a little off topic, but I think you guys are off topic anyway so what the hay.

I saw that "carb style" throttle body and thought, "that would be cool for my setup too. Then I realized that it probably won't work for me because there would be no where to put the MAF. I really don't want to get into an MAF/SD argument.

For right now I'm using the MAF, but anyway...Lets say you had my setup (see sig) w/SD and instead of the Trick Flow intake you used one of those "carb looking" throttle bodies and a spider intake like someone metioned, is there any way to tell which intake would work better without trying it?

EFI benefits with Carb appearance?

maxxfish

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ForceFed70

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SitDown

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Bullitt

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ForceFed70

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