Throttle body EFI (Holley Xflow) vs Multiport on Indy max wedge

[TexasRoadRunner68]

I have trick flow 270s on my 512/400, which means the only intake option I have is the Indy 400 I-2 or the 4500 version.

I did notice for an extra $500, Mancini sells a version set up for fuel injection.

Is the difference worth it? What all do you need to run that vs throttle body efi?


I know certain brands like fitech have bad reps. It seemed like engine masters seemed to think the newer Holley systems were pretty good though.

 

[INTMD8]

I would only do multi port efi. Would rather have a carburetor than throttle body injection. Just my opinion.

 

[Derwud]

I would get the manifold from Mancini and build a Multi Port set-up.

 

[TexasRoadRunner68]

What all

I would get the manifold from Mancini and build a Multi Port set-up.

What all do you need to set one up?

 

[Derwud]

The easy answer is a Edelbrock Pro-Flo 4 and use the Mancini manifold and fuel rails instead of the Edelbrock.. Or build it using Holley parts..

 

[6872n73]

What's the purpose of the build?

 

[TexasRoadRunner68]

What's the purpose of the build?

Mostly street use. But I would like to track it. It’s on the spicier side of street builds. Ideally something I could take on hot rod power tour one of these years and not have durability/reliability issues.

I currently have a Holley xp950 plus for it.

 

[Derwud]

Mostly street use. But I would like to track it. It’s on the spicier side of street builds. Ideally something I could take on hot rod power tour one of these years and not have durability/reliability issues.

I currently have a Holley xp950 plus for it.

What are the specs on your current can including LSA.

 

[TexasRoadRunner68]

Cam specs

 

[451Mopar]

Main difference is the sequential needs to know crank position, so a dual sync distributor or other trigger device so the EFI knows which cylinder it is on.
Batch Fire EFI (includes TBI) just pulses all the injectors at the same time. TBI air/fuel distribution should be about the same as with a carb.
The individual sequential EFI can trim the injectors for the air flow of each cylinder to compensate for different manifold runner airflow, but you would need headers with individual EGT probes or O2 sensors to see the differences.
I'm not sure what the best sequential injection strategy is as far as best crank / piston position to inject the fuel. Maybe avoid intake/exhaust overlap so fuel is not sucked out the exhaust?

 

[6872n73]

110 centerline on the can is a must for efi to auto tune Auto time is nice for the street. You can do lower centerline with efi but but it's not really for the seasonal changes for the street but if you're on the track and adjusting the tune it's fine. I've got 106 centerline Cam that I started out with a carb and it had the roudy should that I liked. I now have Holley hp and the efi has tamed the roudy ness out. idle to about 12-1400 rpms is really tough to tune reliably with auto tune because of the vacuum signal is not consistent and the computer is trying to adjust constantly. The tune can be set to not adjust at that rpm and I can get it run good at this day but the next day it changes slightly.......
EFI will cost more but they're is more to play with when it's done. Adjusting timing and fuel with a few clicks is priceless with instant gratification or sadness.
I will say the worst thing about efi is that it's addictive. I with I had the dominator for more inputs to play with

 

[451Mopar]

Works with big cams and low vacuum, just take a bit more tuning.
"Self-Tuning" is overstated. The newer EFI systems will self adjust the air/fuel ratio (not ignition timing), and only after the engine is warmed up.
You have to program the ignition timing, and the start / cold settings, but the systems come with pre-configured setups that usually work OK.
Also have to verify / compare your actual ignition timing is what the EFI thinks it is.
The EFI did help make the big cammed (270+ duration @ 0.050", 0.726" lift) 499" stroker alot more fun to drive on the street.