Not GN-related but need your opinions guys on choosing an EFI for my Chevelle...…

[toofastforyou]

I'd like to get rid of the carburetor and convert my '71 big-block Chevelle to EFI with a carb-replacement throttle body.

There are several manufacturers out there but after reading a lot on them, I narrowed it down to four choices: either FiTech, Holley or MSD.
There is the FiTech "Meanstreet" :
LINK: http://fitechefi.com/default.asp.pg-MeanstreetEFI good for up to 800hp, then there's the
Holley "Sniper" in 600 or 1,200 hp versions :
LINK: https://www.holley.com/products/fuel_systems/fuel_injection/sniper_efi/ and they also have the
"Terminator Stealth" (which looks like a real carburetor) good for 600hp :
LINK: https://www.holley.com/products/fue...minator_efi/terminator_stealth/parts/550-440K also good for 600hp. Both these Holleys are not out yet but due to be released very soon... and last but not least,
the MSD "Atomic"
LINK: https://www.msdperformance.com/products/fuel_systems/atomic_efi/atomic_efi_tbi/parts/2910 which I'm leaning towards at the moment because I already have a complete MSD ignition system (MSD 6AL box, MSD distributor, coil and plug wires) which can be tied-in to the EFi system allowing to control timing.

All of them come with hand-held controllers to set up the engine's parameters and are self-learning once the parameters are entered into the controller. I guess it all becomes a matter of personal choice… There's just one detail though… MSD says that their "Atomic" is good for up to 625 hp...but I guess it would still be fine for my engine setup (496 cu.in. 698 hp on the dyno) as I rarely use 100% of it's power on the street and have no plans to race it either.

…( I have my Buick GN for that!

…) but seriously, maybe I should give them a call to find out what they're going to say...
Let me know what you think,
Thanks,

Claude.

P.S: I know that FAST also makes a system but forgot to mention it...

 

[87GNSteve]

Do they require you to install an O2 sensor?

 

[toofastforyou]

Do they require you to install an O2 sensor?

Yes they do (I forgot to mention that…) but it's no big deal. Also, some of them can be used with no return line but apparently it doesn't give very good results. The best way to go (no matter which system you choose) is with an in-tank pump and a return line.

Claude.

 

[87GNSteve]

I remember seeing the MSD install on one of those cable TV shows, I was pretty impressed it was real easy they did it on a small black chevy.
I wonder though if you have dual exhaust that doesnt cross? or an H pipe that crosses over way in the back?..... do you just put the o2 on one bank? or at the "H" crossover in the back will it be too cool?

 

[Heskahoka]

I ...
I wonder though if you have dual exhaust that doesnt cross? or an H pipe that crosses over way in the back?..... do you just put the o2 on one bank? or at the "H" crossover in the back will it be too cool?

Reading the MSD instructions, it looks like you can do the o2 in either bank. Personally I would do an H pipe and put it in that for the average of the two banks.
It seems pretty cool that you can integrate the timing with the fuel with the MSD.

Heck, I am thinking you could raise the fuel pressure to get more horsepower than the 625 listed.
Cool project!

 

[toofastforyou]

Thanks Steve and Heskahoka for your replies. I have an "X" pipe on my car but it's about in the middle of the car, too far back…but like Heskahoka said, you can do the o2 in either bank. As for raising the fuel pressure to squeeze out more power, it's a good idea but I don't know if that would work… It's something I should ask MSD about when I'll call them.
Just a sidenote: When my engine made 698 hp on the dyno, that was done with a huge 1,000 cfm Holley "Dominator" carburetor which I replaced with a Holley 4150 series 850 cfm unit when I bought the car for better drivability and I must have lost a few hp's by doing so. That's why I'm thinking that even if rated at 625 hp, the MSD system would probably be fine for me as I don't think my engine makes 698 hp the way it is now...

Claude.

 

[Heskahoka]

Your project got me curious so I did some reading - mostly on the LS1 Tech sites.
Consensus is that ideal placement of the 02 sensor is not in the H or X pipes but more upstream in one of the banks. The H or X pipe may run lean or rich depending on the pulses and pipe layout. Bank side choice for the 02 should the the one that tends to run lean on the engine or the one with better access to change the 02..your choice.
I would stay away from the Holley only because it is so new. I would not want to be one of the first guinea pigs.
I agree that the 625 would be plenty for your car. Have fun with it, whatever you choose.

 

[toofastforyou]

I haven't bought it yet but the MSD makes sense considering it's compatibility with what I already have on the car. Appearance-wise, it's a matter of taste I guess… I just wish that the MSD would be available in a "shiny" finish (like the Holley)… or maybe black…I dunno anymore!

Claude

 

[chasmat2316]

Claude why not spend the money on a port fuel system, I think you would be better off. You could put together a system for about the same money as one of the TBI systems your looking at

 

[Chuck Leeper]

Claude why not spend the money on a port fuel system, I think you would be better off. You could put together a system for about the same money as one of the TBI systems your looking at

My thots, exactly ^^^^^
I see most of those systems are over $2K, and you end up w/ an overpriced 4bbl. An air cleaner on it, and it's just another BBC/Chevelle.

 

[ITSAV6]

Single plane intake with injector bungs and Megasquirt II controller, it's self learning also.

 

[toofastforyou]

Thanks "chasmat2316", Chuck and "ITSAV6". I thought of a port fuel system but I was looking at the TBI systems for several reasons: It's not a question of price but rather a question of keeping it simple . I don't really feel like having to tune the system, just bolt it on and start the car and it self-learns...
1° With a TBI, I wouldn't have to change the intake manifold (which is already is single plane), and polished and ceramic coated,
2° the throttle, kick down cables and bracketry remain the same as well as (keeping the same air cleaner which is painted to match the valve covers)
3° It would also retain the '70's retro look which is ok for a '71 Chevelle. I do shows with the car, I spent a great deal of money detailing it and make it look good, so to me it's important that everything remains looking good… (See pic below…)

As for performance I don't know if there are advantages of a port fuel system over a TBI system but keep in mind that I don't have any plans to race that car.

Thanks guys, I appreciate,

Claude.

 

[ITSAV6]

Megasquirt II self learns also, does timing, and provisions for lots of upgrades too. Speed density or maf, flex fuel and knock sensor and lots more.
https://www.diyautotune.com/product/megasquirt-ii-engine-management-system-w-pcb3-assembled-unit/

 

[Heskahoka]

I haven't bought it yet but the MSD makes sense considering it's compatibility with what I already have on the car. Appearance-wise, it's a matter of taste I guess… I just wish that the MSD would be available in a "shiny" finish (like the Holley)… or maybe black…I dunno anymore!

Claude

The MSD throttle body looks to be aluminum. I am betting that you could polish it before you mount it.
You have a real nice engine bay, I understand why you would want to keep it shiny.

 

[toofastforyou]

The MSD throttle body looks to be aluminum. I am betting that you could polish it before you mount it.
You have a real nice engine bay, I understand why you would want to keep it shiny.

Yeah maybe it could be polished…but it's hard to say just by looking at the pictures. Also thanks for the good comments about my Chevelle's engine bay, I appreciate!
BTW…here's picture of the whole car…

Claude.

 

[chasmat2316]

The car Is beautiful!

 

[Heskahoka]

That car could lure me away from the Dark Side!

 

[20psiofevil]

If it were mine I'd research the fitech. Mega squirt has come a long way as well.

 

[toofastforyou]

If it were mine I'd research the fitech. Mega squirt has come a long way as well.

Yeah I checked FiTech also…they have their "Meanstreet EFI" unit good for up to 800hp which could also be an excellent choice.
LINK: http://www.fitechefi.com/default.asp.pg-MeanstreetEFI

Claude.

P.S: Thanks "chasmat2316" and "Heskahoka" for your good comments!

 

[czimpel]

Beautiful Car Claude!