Efi?
 

this is verry hypothetical right now, but not so much in the future but..

What is the best EFI system for a 400ci motor and vortec heads? How would the driveablity change? MPG? Does efi come in complete kits, with wiring harness's and ecm's? How would I get tuned?

http://store.summitracing.com/egnsea...4294901803+115

that should give you an idea of what it'll cost for good fuel injection. I'm doing my MPFI 388 a little different. Also the Vortec heads make it very expensive.

WF, your best bet (given your budget) will probably be a retrofit of a TPI system or something like that.

probably...but on his motor it wouldn't be worth the power gains

Not sure I follow you bubba. What do you mean?

Interesting a TPI 400ci engine. I'm a noob with this stuff (though I own the TPI book). I wouldnt think the intake manifold, injectors / rail or heads would fit a 400ci. Decent amount of fitment / fabrication needed right?

I'm really just throwing that out there... I'm not up on my TBI/TPI, etc. stuff. Most regular Gen I small block parts will fit on a 400.

ud need a pre 87 tpi manifold normally but i dont no with the vortech heads

Because of the vortec heads any type of EFI is going to be expensive. so for that amount of money I would just go all out and do an MPFI system, which features the fuel injectors in each runner for maximum HP gains. Not to mention the link I sent was for a VERY high flow intake and all of the options were for the vortec heads on a 400SBC. TPI is the predecessor of MPFI, MPFI works better than TBI or TPI because of the way it fires the injectors. I'm gonna do my EFI388 with the same manifold and a Megasquirt system just like I got for the V6. With the Megasquirt you can also run DIS if its to your fancy, and they all come with a built in nitrous window switch. so by doing it that way you get more options and your knocking the price down $1,000.

See, I don't see it that way. A lot of Vortec headed cars are/were fuel injected so adapting a setup to his 400 doesn't seem like it would be that expensive.

For the $2-3k that the Holley system costs he would be better off just buying a used LS1 or something like that.

JMO.

TPI systems ARE MPFI. all MPFI means is multi port fuel injection. it if has a fuel injector for every cylinder, its MPFI. now you could argue that some TPI systems are batchfire and some are sequential, meaning one fires an entire bank at once and the other fires each cylinder at once, respectively.

*edit*

you'd be better off going with a system like edelbrock's pro flo system. carb style intake with a throttle body on top, drilled and tapped to accept fuel injectors.

thats why I said :nod:

but, tpi is not the predecessor of mpfi. TPI IS MPFI

well if you look at it as the fact manufacturers don't call it TPI anymore. any way you want to call it an injector per cylinder is better than 2 for all 8 (TBI) or a carb. Its much more efficient in terms of fuel consumption to the amount of power made by the system.

the reason its called tuned port injection is because the intake runner lengths are tuned. TPI is still a multi port system because it has an injector for every cylinder.

/MPFI argument

What manufacturers don't call it TPI? Where do you get all your info from???

He could easily order the Vortec TPI intake and go with TPI. I think Jegs sells the Vortec manfiold IIRC...

Converting to EFI would require allot of work. Your easiest solution would probably be to find a TPI set-up from a 3rd gen and install that.

Aftermarket kits would require allot more work and fabritaction.

When you say "best" do you mean best as in easiest to convert or would work best for you application, or best as in above all others? If I could afford any system I would buy a Motec system. Probably has more abilities to manage and monitor more things that any other.

http://www.motec.com/products.htm

Motec has some neat stuff, none of which is cheap!

Not really up on my 400 info but why not just get the Vortec baseplate for the Holley StealthRam setup and run that? Fairly inexpensive and it will flow enough to support the cubes.

Why not just leave it carb'd. ANY fuel injection is going to be alot of work. Say you go with a TPI you need a TPI set-up for Vortech heads, new wiring harness, New computer since all the TPI cars had a different style then the 84, fuel sender, fuel pump, different fuel lines at the very least in the front. Chances are you will break at least one line and the fuel tank will be rusty on the top so you can replace those etc etc. Your car was designed to run on a carb so I'd keep it that way.

Also TPI is a form of MPFI, don't get it confused with SFI (Sequential fuel injection) like on the newer cars. I also don't know how much you would save fuel wise, definately a little but the TPI fires 4 injectors at a time. I don't think you could switch to EFI properly without dropping at least $2000.00-$3000.00 so just leave it be.

MPFI is any fuel injection system that uses a fuel injector for each cylinder. TBI is NOT MPFI, for example.

sequential just means that every time the intake valve opens, the injector fires for that cylinder.

batch fire is where the right and left banks fire all at once (first the right side, then the left side or vice versa). the downfall of this is that out of the 4 injectors that fired (assuming this is a V8 motor) only one was fired at an open valve, the other three were fired at the back side of a closed valve.

Not all TPI cars were batch fire, the early ones were, but the later ones werent. I dont know the change over year, but I know SD cars were sequential.

I hope this helps clear things up a little bit. :)

WayFast, I researched all of this stuff and got most of the way there before I decided to go carbed on my Vortec 406. If you want power gains, don't go for a factory TPI system. They tend to run out of breath quickly. If you want simplicity, go for a TBI system. You can get a TBI throttle body from a later model 454 that will feed the 400 just fine. Same caveat as the factory TPI applies. My choice was the Holley Stealth Ram for Vortec heads. I tried pieceing it together using an ECM from a late 3rd gen, but I would suggest just buying the whole kit.

I just wanna make it clear that the only reason I was switching to EFI was because at the time my '81 was going to have to function as a daily driver and I wanted something more fuel efficient and reliable in the winter, not for performance gains. Since I have my 4th gen DD now, I went back to the carb.

From what I heard on TGO, People are having tons of problems with tuning. Right now, im just going to drop this idea for the future completly. Who ever said an ls1 swap would have been more ethical is probably right.. thanks guys

I know GM used batch until 93 in the Vettes and F-bodies.

Wayfast, just remember that a stock FI system is nowhere near as flexable as an aftermarket system. My electromotive system can control low inpedance injectors, has a rev limiters bulit in that can be set to either reduce fuel pulse or pull timing, a bulit in two step, 2nd fuel pump control ( I can turn on a secondard FP at a certain RPM), and a port that can be activated by throttle postion or Map sensor (reading boost) that can activate nitris or alki. And the software provides full graphics. And this would be on of the less expensive systems.

I stand corrected, so for the misinformation.

Just another oddity of the 93s. I could never figure out why GM would go this way since they had such success with the Grand National's using SFI.

Must have been some cost involved???