Mass Air -OR- Speed Density

[429Mustang429]

I have a good question for all of those of you who have messed around with the EEC-IV systems. I recently totaled my 92 Notch 5.0, 5 speed, red w/black int. (trust me, I'm still mourning the loss). I am now building an 89 vert and want to go a little CRAZY. Planning on running a TRUE blower, -not supercharger-, the type that mounts on top of the engine and has the carbs sitting on top. I want to still run fuel injection, however.

Now, on to my question. Does any one have experiance in speed density and tuning capabilities if I'm pushing boost? The reason I want to run speed density is because i wont have a place to put the mass air meter. I know that i shoulod stick with carbs also, but I really WANT to run fuel injected. I can fab my own intake and all that, (i know it will be a lot of work, but once agian, I want to run fuel injected).

Any help would be greatly appericated...Thanks, Darren.

 

[BK_CAULEY]

how are you planning on running a carbed blower with an EFI setup? why done you just use a kenne bell with a gt 40 lower? i see no way to setup a carbed blower for EFI the base isnt going to work unless you can fab it up for injectors.

 

[429Mustang429]

how are you planning on running a carbed blower with an EFI setup? why done you just use a kenne bell with a gt 40 lower? i see no way to setup a carbed blower for EFI the base isnt going to work unless you can fab it up for injectors.

I am going to build my own custom intake with bungs for the injectors. I am also going to make an adaptor plate that goes where the carbs sit and run 2 throttle bodies up there. I have to make custom linkage and fuel rails also. I've been pondering how to run the damn system, but if i get it to work , i think she'll look bad ass.

I know that it would be a lot easier and more time effective to run a bolt on kit, but i want to have that big blower stickin up through the hood, but hopefully be a little easier on gas, and start easier/run better in colder weather. (i know it wont be that easy on gas, i'm most likely runnin 42-52lb injectors) lol.

 

[BK_CAULEY]

I am going to build my own custom intake with bungs for the injectors. I am also going to make an adaptor plate that goes where the carbs sit and run 2 throttle bodies up there. I have to make custom linkage and fuel rails also. I've been pondering how to run the damn system, but if i get it to work , i think she'll look bad ass.

I know that it would be a lot easier and more time effective to run a bolt on kit, but i want to have that big blower stickin up through the hood, but hopefully be a little easier on gas, and start easier/run better in colder weather. (i know it wont be that easy on gas, i'm most likely runnin 42-52lb injectors) lol.

as for the throttle bodies FAST makes one that mounts in place of a carb. and if you are going to make your own injector bungs just run new set of rails and new fuel lines to connect them. i seriously doubt stock rails will clear.

anyways here is the throttle bodies.
http://www.fuelairspark.com/Products/details/manifolds/throttle.asp

FYI most high horsepower boosted (turboed) cars are speed density based. they also use FAST, BS3, AEM style ECM's too.
So the benifits to mass air = easier tuning, and it'll generally accept more engine mods before re-tuning is required.

Benifits to speed density = No expensive mass air meter, mass air meters are also an intake restriction so they hurt HP a little. Speed density also doesn't care about a vacum leak (which totally screws up a mass air system). A vacum leak usually only results in a high idle. Speed density allows for more tuning flexibility (at the expense of being more complicated to tune).

 

[429Mustang429]

as for the throttle bodies FAST makes one that mounts in place of a carb. and if you are going to make your own injector bungs just run new set of rails and new fuel lines to connect them. i seriously doubt stock rails will clear.

anyways here is the throttle bodies.
http://www.fuelairspark.com/Products/details/manifolds/throttle.asp

FYI most high horsepower boosted (turboed) cars are speed density based. they also use FAST, BS3, AEM style ECM's too.
So the benifits to mass air = easier tuning, and it'll generally accept more engine mods before re-tuning is required.

Benifits to speed density = No expensive mass air meter, mass air meters are also an intake restriction so they hurt HP a little. Speed density also doesn't care about a vacum leak (which totally screws up a mass air system). A vacum leak usually only results in a high idle. Speed density allows for more tuning flexibility (at the expense of being more complicated to tune).

Excellent!!! Thanks for the input.

 

[BK_CAULEY]

Excellent!!! Thanks for the input.

you can also get complete stand alone EFI sytem form those same companies. i imagine you can move the stock components around to work but you are definatly going to want to get a 1987 speed density cars harness and ECM.

what is your power goals for this project?

 

[429Mustang429]

you can also get complete stand alone EFI sytem form those same companies. i imagine you can move the stock components around to work but you are definatly going to want to get a 1987 speed density cars harness and ECM.

what is your power goals for this project?

Not really all to sure yet. i hope to make about 5-600 horse, but i really dont know how well the block and internals will stand up to the challange. I have a 1971 351w block, forged pistons but i am planning on running stock rods and crank for now.

 

[BK_CAULEY]

Not really all to sure yet. i hope to make about 5-600 horse, but i really dont know how well the block and internals will stand up to the challange. I have a 1971 351w block, forged pistons but i am planning on running stock rods and crank for now.

a 351 will handle it. but thats about the limit of it. let us know how it turns out.

 

[BK_CAULEY]

double post.

 

[Gears & Crosses]

Good Luck on your ambitious project. It will definitely have a unique look. We need to see pics when you are done.

Although I like the bungs in the manifold idea, if you run into problems with this method, you could run the injectors on top of the blower. I really believe this has been done before too (BDS?). Injecting the gas up top helps cool the roots style blower (from what I hear)and maybe a better mixture? You may also look at running true F.I. throttlebodies up top too.

Like previously mentioned, it sounds like a stand alone aftermarket FI system with an optional boost sensor is what you are looking for. A friend of mine used a SDS system on his twin turboed 350 in a older Supra. Everything on the FI system was custom except the cumputer and harness.

Let us know how it works out,
Gears

 

[429Mustang429]

Good Luck on your ambitious project. It will definitely have a unique look. We need to see pics when you are done.

Although I like the bungs in the manifold idea, if you run into problems with this method, you could run the injectors on top of the blower. I really believe this has been done before too (BDS?). Injecting the gas up top helps cool the roots style blower (from what I hear)and maybe a better mixture? You may also look at running true F.I. throttlebodies up top too.

Like previously mentioned, it sounds like a stand alone aftermarket FI system with an optional boost sensor is what you are looking for. A friend of mine used a SDS system on his twin turboed 350 in a older Supra. Everything on the FI system was custom except the cumputer and harness.

Let us know how it works out,
Gears

Its going to be a pain in the ass, but it should be a fun project... i didnt think about injecting before the blower, but thats basicially what the carbs do...good point. i have a lot of friends in fab shops that are willing to help out so this should be a fun learning experiance.

 

[Roland69]

I don't know what would be best for what you want to do But I am a fan of SD myself

 

[65ShelbyClone]

Planning on running a TRUE blower, -not supercharger-, the type that mounts on top of the engine and has the carbs sitting on top.

Both are the same thing, FYI.

Port injection is an option as is TBI. The TBI setup will act similar to a carb...just make sure your bower is designed to be a wet flow type.

Regarding MAF vs. SD, that depends on what (standalone) EFI system you're going to use. Most are SD-ready, but some are MAF capable as well (like MegaSquirt). As far as which is better, I would say neither. Each just has a specific way that they are tuned.