MPFI tech

[STEBS]

had a few idea's pop into my head the other day, and i cant find didly to support it...

ive always been a fan of early carbed small blocks, and this last year ive been doin a lot of research into TBI just for the simple fact that not alot of people really mod TBI's all that much and i also have a plan for a 400tbi for a "stock appearing" gmt400 project down the road... but a couple days ago i got off on a MPFI kick, and cannot find anything on it

i can find the Holley MPFI kits, but as far as "hard info" or numbers, i cant find it... every search i do is either: TBI to MPFI, or carb to TBI, or TBI to carb, or LS swaps or voetc's, or people talking about TPI, or ramjet... and im not doing anything like that... hell half the time i do internet or youtube searches for "chevy 350 MPFI" and it comes up with all these damn honda rice tuners... i wasnt a genious in highschool, but im pretty sure "chevy 350" has absolutly NOTHING to do with honda... just sayin

ive got a few ideas for an engine with a MPFI setup, but with out any information i cant really plan ahead. is there a reason every1 keeps talking about TPI or ramjet? im curious what all id look at doing for a hot little street engine, upgraded vortecs, or mild aluminumn heads... whats a good cam profile to go along with the fuel injection... what do i do bout spark timing? what kind of numbers can systems like this bring on the dyno and at what cost... how do u decide on injectors when u cant find info on a potential powerband with parts u may or may not use? the kit is $3k+ and says its supposed to be a "plug and go" install... so does that mean it will work best with a stock set up, or do i need to have mild or better upgrades? any kind of fuel miliage increases? i mean theres so many questions unanswered but yet i cant find answers... im still a little new at the whole fuel injection thing, so am i missing something or?

 

[STEBS]

and if i do searches on EFI swaps, it all comes up with the TBI style 4bbl injection... its almost like nobody runs fuel rail EFI intake set ups, or if they do it aint talked about much

 

[great white]

TPI comes up because it is MPFI.

TPI is batch fire MPFI as opposed to sequential fire though.

I put TPI on my old 89. Was a pita. Was a great conversation piece when in lifted the hood.

I started with the original 7747 ECM modified for batch fire TPI, then moved up to a 7427 PCM, eventually converting the truck to obdII and running a 411 PCM. If I was to do it all over again I'd likely just buy an EBL (modified 7747 ECM: http://www.dynamicefi.com/EBL_Flash.php) and be done with it.

The old TPI was good for low end torque on a SBC, which is what they were designed for. I've still got two full systems in the garage. They're "wall hangers" though. TPI swaps are long past thier prime when things like an LS series engine (also mpfi) can be had for not much more than a song these days.

Ram jet comes up in your searches because it it also MPFI.

All MPFI means is Multi Point Fuel Injection. Even the newer vortec's with the leaky OEM poppet injection are considered mpfi....so are Hondas, Nissans, Fords and Chyslers with one injector point per cylinder.

Heck, even my 6.5 diesel can be considered MPFI.

The 4bbl style FI comes up because it is relatively cheap, easy to dial in and gives good results. Its also pretty much bolt on if using a kit.

There are also 4bbl kits that look like TBI, but the throttle body is just the blades and the modi is down on the I take at the ports. For example: http://www.google.ca/url?sa=t&rct=j...=kY8NBkf60gGrNiGKq7cjDw&bvm=bv.59026428,d.cWc

This would have been another option when I did TPI on my old 89, but back then it was all pretty new and prohibitively expensive so it was pretty much roll yer own or pay out the nose.

I was in the roll yer own crowd....mostly because of cash flow deficit....

 

[superdave]

There are also 4bbl kits that look like TBI, but the throttle body is just the blades and the modi is down on the I take at the ports. For example: http://www.google.ca/url?sa=t&rct=j...=kY8NBkf60gGrNiGKq7cjDw&bvm=bv.59026428,d.cWc

This would have been another option when I did TPI on my old 89, but back then it was all pretty new and prohibitively expensive so it was pretty much roll yer own or pay out the nose.

I was in the roll yer own crowd....mostly because of cash flow deficit....

That's still a pricey option at over 3 grand. I understand cash flow deficit.

 

[great white]

That's still a pricey option at over 3 grand. I understand cash flow deficit.

For sure. Was just meant as an example of what's available.

Most "prepackaged" stuff is going to be around the 2-3 grand mark.

A smart shopper should be able to get it all done for 1,000-ish plus a good deal of learning how to calibrate and EFI system...

 

[STEBS]

There are also 4bbl kits that look like TBI, but the throttle body is just the blades and the modi is down on the I take at the ports. For example: http://www.google.ca/url?sa=t&rct=j...=kY8NBkf60gGrNiGKq7cjDw&bvm=bv.59026428,d.cWc

the other EFI kits that resemble TBI, like the EZ EFI kits, i like how simplistic they are, but still not what i had in mind, so that bein said with there popularity, is it basicly like the best bang for the buck cuz its cheap fuel injection

thats the holley kit i had refered too, and want to do something with but cant really find much out about possible combinations with it. is it just so damn expensive that not many people even bother with the kit? (holley makes a simular kit for only 1500 but you supply the fuel injectors and pump http://www.jegs.com/i/Holley/510/550-701/10002/-1?parentProductId=761891 ) is it a matter of tuning that turns ppl away (since you mentioned the ease of the wet injection tuning above)

 

[STEBS]

i stand corrected on the holley kit fer 1500 i mentioned, i didnt see last night that its as bare bones as it is. it said to supply injectors and f/p of choice, but until just now, i didnt see that it doesnt come with any ecm, wiring harness, sensors, etc... how hard (and technical) would it be to "roll my own" mpfi set up like this to turn it into a full functional system?

so its basicly back to the first holley kit i had looked at thats over 3k, i seen that ACCEL makes a simular MPFI kit for 4k but even includes the hardware for spark control http://www.jegs.com/i/DFI/310/77142EB/10002/-1?parentProductId=1123885

 

[great white]

Well, you could roll your own, but it wouldn't be a nice as the holley kit.

Grab a SBC aluminum 4bbl manifold. Weld bungs in to fit the injectors. Then the injectors and rails off a TPI setup (or similar, chose it before welding bungs). Toss in a tps, map sensor and O2 senor to run the ECM. Fuel pump and a regulator.Then work out something you can use for a throttle body. You could make do with an old square bore stripped and worked over I guess.

Toss in a couple assorted bits to tie it all together.

Grab an EBL for ease of setup and programming.

get real familiar with wiring diagrams and tuning.

That should drop you right around a grand or so. But it would sure be one hell of a junkyard dog.....

 

[STEBS]

Well, you could roll your own, but it wouldn't be a nice as the holley kit.

Grab a SBC aluminum 4bbl manifold. Weld bungs in to fit the injectors. Then the injectors and rails off a TPI setup (or similar, chose it before welding bungs). Toss in a tps, map sensor and O2 senor to run the ECM. Fuel pump and a regulator.Then work out something you can use for a throttle body. You could make do with an old square bore stripped and worked over I guess.

Toss in a couple assorted bits to tie it all together.

Grab an EBL for ease of setup and programming.

get real familiar with wiring diagrams and tuning.

That should drop you right around a grand or so. But it would sure be one hell of a junkyard dog.....

thats kinda what i figured it would take, and honestly i wouldnt be scared to try it (intimidated as hell, but not scared) ... alot of fuel injection confuses me just for the fact i have ADD, so some concepts just dont "click" like they do for others, but when im able to channel my focus (thats where all my research and ideas and inquiry comes in) into something in peticular than i can do extraordinary things like roll my own MPFI system

now that being said, if i were to start off with, lets say a TBI or vortec base.... we'll use TBI for the sake of argument... say i find me an ol early 90's SWB 2wd... would i find the pin out for the ECM and basicly change the in and outputs to make the system work and then still be able to use the majority of the factory sensers and wiring? or since vortec is already MPFI, would i utilize that ecm with this sytem for the truck in question?

 

[superdave]

It seems like a bare ramjet manifold for about $500 would be a good place to start. Seems like an adventurous sort could junkyard the rest, but the manifold fab work would be skipped, and it's purdy.