Anybody heard anything about this carb style EFI?

I use a similar EFI system in my '70. Although I chose to use a megasquirt ECU with a holley 900cfm TBI unit.

Those of you who are interested in this Boss EFI unit.. have you checked out the similar offerings from Edelbrock and Holley?

From a horsepower perspective, the further your injectors are from the intake valve, the more power you will make(to a point). This is due to better fuel atomization, and the cooling effect that goes along with it.

The downside of throttle body injection vs a port based system is that it has slightly less throttle responce. Particularly at low RPM and low throttle. Still better than any carb tho (if tuned right), but not as good as port injection.

How does this system stack up against the Mass Flo EFI system? How is it better and how is it worse?

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They are completely different EFI technologies. Mass flow system uses a mass air sensor, whereas the bossEFI system uses speed density(Manifold absolute pressure). You'll need to do some research as to the pro's and con's of each system. In a nutshell, speed density is more complicated to tune and requires re-tuning for significant engine combo changes. BUT, it doesn't require an expensive mass air sensor which acts as an intake restriction and costs HP. Mass air is easier to tune and doesn't need to be retuned for minor engine changes. But tends to make less power due to the restriction caused by the mass air sensor. Then there's the injector placement. The mass flow system uses port injection, the BossEFI uses throttle body injection.

Other pro's and con's... The BossEFI system let's you keep the "carb'd look" and you can use your existing intake manifold with no modifications. The BossEFI system comes with a tuneable ECU where the Mass Flow system gives you a factory ECU and you'll have to buy an aftermarket tuner if you want to tune it.

C'mon some one buy one and try it out......I too have used TBI the holley projection and loved it both analog and digital, the digital was a bitch to tune though but the throtlle response was killer and power, the only carb that has been close has been my demon. The thing that interests me besides the self learning and I believe that is due to the wide band 02 setup which would let you dial in A/F ratios at any given point is that it uses high pressure injectors which is different than other "TBI" systems so I would think the fuel would be even more atomized, Barry Grant had a cool TBI called VFI which used injectors and carb venturis but I havent seen it for a couple years.

I'm forking out 700.00 for a new prosystems carb tommorow for my new 408 but somewhere down the line I want to inject it again and the boss efi is interesting.

Did you guys catch the "no need for a fuel return line" if your under 500 h.p.?!
I've been looking at the holley Tbi system but this one sounds like it eliminates the need to modify my fueltank, I'm I reading the site correctly?

If the fuel pressure is adjusted by a PWM controller as the site suggests there must be a fuel pressure sensor that determines when to pulse the fuel pump.

htwheelz67 said:

C'mon some one buy one and try it out......I too have used TBI the holley projection and loved it both analog and digital, the digital was a bitch to tune though but the throtlle response was killer and power, the only carb that has been close has been my demon. The thing that interests me besides the self learning and I believe that is due to the wide band 02 setup which would let you dial in A/F ratios at any given point is that it uses high pressure injectors which is different than other "TBI" systems so I would think the fuel would be even more atomized, Barry Grant had a cool TBI called VFI which used injectors and carb venturis but I havent seen it for a couple years.

I'm forking out 700.00 for a new prosystems carb tommorow for my new 408 but somewhere down the line I want to inject it again and the boss efi is interesting.

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yeah, i too thought it looked very similar to the BG VFI as well, in fact i'm seriously wondering if BG sold the rights to it to these guys. BTW, the Pro-Comp Electronics guys have already ripped this one off too, either that or this company is a "division" of Pro-Comp, don't know which though.

BottleFed70 said:

,,,,,,,,,,They are completely different EFI technologies. Mass flow system uses a mass air sensor, whereas the bossEFI system uses speed density(Manifold absolute pressure). You'll need to do some research as to the pro's and con's of each system. In a nutshell, speed density is more complicated to tune and requires re-tuning for significant engine combo changes. BUT, it doesn't require an expensive mass air sensor which acts as an intake restriction and costs HP. Mass air is easier to tune and doesn't need to be retuned for minor engine changes. But tends to make less power due to the restriction caused by the mass air sensor. Then there's the injector placement. The mass flow system uses port injection, the BossEFI uses throttle body injection.

Other pro's and con's... The BossEFI system let's you keep the "carb'd look" and you can use your existing intake manifold with no modifications. The BossEFI system comes with a tuneable ECU where the Mass Flow system gives you a factory ECU and you'll have to buy an aftermarket tuner if you want to tune it.

Click to expand...

This new Boss system uses wideband o2 sensors. And is using a completely new ECM. What we know about tuning/modding the old Speed Density (MAP) systems from the may not apply. I'm hoping that that using wideband sensors will make this a true self learning system and manual tuning would not be needed in most cases.

how is a speed density setu self-learning? how would it know I want 15:1 on the highway and 12.5:1 at WOT?