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-   -   decision time!! carb or efi (https://www.rx7club.com/1st-generation-specific-1979-1985-18/decision-time-carb-efi-423826/)

GTRay 05-10-05 09:20 AM

ok, maybe i was a bit pesimistic on my original post but i think a lot of crucial information is overlooked when the only that is posted is "how easy this is"

you're right, the 12a doesn't need EFI manifolds - i've been in this game for far too long to try adapting 13B EFI parts onto a 12A. I would start with a downdraft carb manifold and go with an InjectionPerfection TBI. kits can be found that contain 4 injectors, TPS, throttle body, velocity stacks, and fuel rails - ALL IN ONE! talk about a sweet looking setup!

while there are guys out there that swear by the megasquirt kit i'm still partial to the microtech units. the available add-ons and tuning features of the microtechs still impress me. and yes, before anyone trumps me on this i do have a previous relationship as a dealer for microtech - there, now my bias is in the open :-)

when it comes to a project like this planning is the MOST IMPORTANT part!

always give yourself options and realize that some parts of the project will become expensive.

my opinion of junkyard parts, especially wiring harnesses, is pretty low. the youngest SE you're going to find in a junkyard is now 20 years old. 20 years of age, neglect, repair, and sometimes abuse are going to take its toll. if you want to go EFI and your car was built for a 12A i would suggest leaving it a 12A and using an already available aftermarket kit such as the microtech or haltech unit that comes with an already constructed wiring harness. if you want to purchase a bundled kit that includes almost all the parts you will need to convert from carb to EFI i will be more than happy to help you with your setup.

pull the engine, rebuild it and design your EFI system. if you need help with the design process be sure to ask. an organized list of parts is crucial!

pm me if you have any specific questions about planning your project.

Ray

GTRay 05-10-05 09:24 AM


Originally Posted by Elysian
http://www.auto-nomics.com/cgi-bin/s...rt=10850-002-D

and yes, i understand it still needs 2 fuel rail, some injectors, probly a throttle position sensor, but use TII injectors with that and u won't have to spend a ton...


hehe... TII injectors are at a premium right now. most of the import crowd has realized that turbo rotaries are thirsty and require big injectors from the factory. 550cc injectors are seeing a big demand right in everything from civics to supras.

Ray

CODE BLUE 2 05-10-05 09:35 AM

I decided to do the change over from Carbed to efi/ecu. "Microtech" on my 79 supercharger. Its not cheap, but well worth the switch. I have a 13b 4 port. If you have any questions on the goods and bads catch me on aim or pm.

QuagmireMan 05-10-05 09:43 AM

motec!!

drunkclever 05-10-05 11:04 AM

just for now i think I am going to throw the 13B in and make as close to stock as I can get it. If I can get the stock harness and ecu in the bone yard thats what I am going to roll with for now. While I wait for my rex account to get fatter, this will allow my plans to mature to the point where it can just fall off the brain tree.


At the moment I am looking to up grade the fuel system. I have found various choices :

http://store.summitracing.com/partde...=KeywordSearch

edit.
in a word.. overkill.. http://store.summitracing.com/partde...=KeywordSearch

i guess finding a complete ready-made-tested system for fuel delivery isn't that hard... or is it? will the first one work just fine?

vosko 05-10-05 12:02 PM

why are you gonna spend that much?

85rotarypower 05-10-05 12:40 PM

Well, I have to suggest carb if your not planning on using lots of boost (under 15 psi). If you use a holley setup, boost preping the carb is very easy and tuning a holley is easier than anything. Everything is readily accessable by removing the fuel bowls. From there its just as simple as taking out a screw and replacing it. just get a full set of tuning parts and your set. It takes time to tune a carb, but IMO its much easier.

Elysian 05-10-05 12:45 PM

i went with a holley setup on my SP 6 port 13B, but thats only a temporary solution till i get everything i need to go FI, then i'll take some time to FI it, and hopefully be running with minimal down time, tho with my record, nothing goes as planned, and down time will be huge lol

GTRay 05-10-05 01:15 PM

interesting...

the first pump you picked out is a low pressure pump meant to be used with a carbed system. that pump won't work in an EFI application where your rail pressures need to exceed 40psi.

i would reccomend these pumps:

Bosch Fuel Pump part number: 0580 254 044

-or-

MSD -2225 http://store.summitracing.com/partde...3&autoview=sku

these pumps will flow a great deal of fuel at the required pressure and will also work when you start building your turbo system. you can source most of the plumbing locally or purchase it directly from summit as well. you're on your own for locating the bosch pump - most bosch dealers will be able to find it for you though, just give them the part number.

next you're going to need a surge tank/swirl pot. the swirl pot is designed to serve two purposes. it serves as a buffer between your unbaffled factory fuel tank and the increased flow requirements of the EFI fuel pump and it seperates the air from the fuel. by swirling the fuel inside the tank it sends the heaviest, most dense fuel to the boundaries of the tank, leaving the lighter fuel and air in the center. this gives you a more consistent fuel pressure and density than most standard systems. assuming there is clearance under the hood i prefer to mount that equipment on the firewall or the inner fender well for easier access. if you choose to mount this equipment under the hood you need to be sure that you insulate it from any source of heat - we all know what happens when gasoline gets hot :-)

if this car isn't going to be daily driven or expected to make a serious journey then i would suggest maybe a 5 gallon fuel cell to replace the factory tank. that way you can dump some weight and build a more "propper" fuel system.

the next most important part in your system will be the fuel pressure regulator, for that i would suggest this particular FPR:

Aeromotive A1000-6 http://store.summitracing.com/partde...0&autoview=sku

that regulator will serve you well in conjunction with the MSD fuel pump and again, provides the rising rate function desired for turbo applications.

after that it's all a matter of picking out the equipment you want to inject the fuel. since you are going with the SE engine i'm assuming that you'll also be using the SE manifolds and injection equipment which will make installation and tuning quite a bit easier. infact since you're using the SE stuff you will already have the fuel injectors, fuel rails, and fuel pressure regulator for the factory application and some mild performance tuning beyond that.

Ray

Elysian 05-10-05 03:27 PM


Originally Posted by GTRay7
next you're going to need a surge tank/swirl pot. the swirl pot is designed to serve two purposes. it serves as a buffer between your unbaffled factory fuel tank and the increased flow requirements of the EFI fuel pump and it seperates the air from the fuel. by swirling the fuel inside the tank it sends the heaviest, most dense fuel to the boundaries of the tank, leaving the lighter fuel and air in the center. this gives you a more consistent fuel pressure and density than most standard systems. assuming there is clearance under the hood i prefer to mount that equipment on the firewall or the inner fender well for easier access. if you choose to mount this equipment under the hood you need to be sure that you insulate it from any source of heat - we all know what happens when gasoline gets hot :-)

stock tanks are baffled... the 12A tank just doesn't have that bowl deal(can't remember itsname now) in the middle of the tank... we had a thread on this recently, with pics included...

jayroc 05-10-05 04:06 PM

On the holley setup, I'm just saying watch out for the extras. I've emailed and talked to the guy and this is what I'm basing the number on:

T-body 75
TPS 40
IAC 60
Machining-TPS 30
Machining-IAC 60
Adapter ring 15
Fuel rail assy 115
Total $395

Actually, it is a bit more, but at $400, it's still a sweet deal. The TB itself has to be machined to accept the IAC and TPS. Of course, you don't NEED those two, but it helps in tuning. In that case, you could get by with knocking 190 off for the sensors solenoid and machining..
I have a set of s4 FC injectors and plan on getting them cleaned for $100, then finding a mani for $150 or so used.. ECU and misc hardware, if using megasquirt, would run around $400.. Cheaper maybe, if you're frugal or find a good deal someplace.. I have this stuff already, tho.
So, $1k for a very good EFI conversion is not unreasonable. Cheaper if you got a SE and aren't going from carb.

But right now, I'm broke, so it's all just planning.. Trying to sell my old setup, ATM, dunno if I mentioned that.. ;)

Here is what my setup looked like http://www.mindspring.com/~wilkinsjr/my%20car%20pics. Engine bay is a bit dirty.. Check the pics from February.

drunkclever 05-11-05 08:29 AM


Originally Posted by GTRay7
next you're going to need a surge tank/swirl pot. the swirl pot is designed to serve two purposes. it serves as a buffer between your unbaffled factory fuel tank and the increased flow requirements of the EFI fuel pump and it seperates the air from the fuel. by swirling the fuel inside the tank it sends the heaviest, most dense fuel to the boundaries of the tank, leaving the lighter fuel and air in the center. this gives you a more consistent fuel pressure and density than most standard systems. assuming there is clearance under the hood i prefer to mount that equipment on the firewall or the inner fender well for easier access. if you choose to mount this equipment under the hood you need to be sure that you insulate it from any source of heat - we all know what happens when gasoline gets hot :-)


i did some searches and found this

http://toyotaperformance.com/surge_tank.htm

i wonder if this will work? also is that best way to rig everything up?

jayroc 05-11-05 12:07 PM

I bought a side mount tank from tweakit. Worked out well. Had to weld on a fitting to reduce the output barb to 5/16, though..

Elysian 05-11-05 05:35 PM

hm i was figuring on trying to find a GSL-SE tank, but it might just be easier to do a surge tank setup... GSL-SE's aren't common here in WA....

GTRay 05-11-05 09:48 PM

in my opinion, the surge tank method is always the easiest way to do it.

Ray

tasty danish 05-11-05 11:06 PM

personally i'd go carb just because i think it's cooler.
i don't think many of us drive our cars everyday, so stop bitching about gas mileage.
everyone goes FI because it's the obvious thing to do, it's better, that's why carbies are so cool, no one does them, and when you are faster than FI, it's just that much cooler.

kind of like old ford flathead engines. SLOW. However, i've seen guys supercharge them and run 12's.
sure other engines can be faster, but half as cool?
hell no.

Elysian 05-11-05 11:20 PM

maybe u don't drive ur car every day, my FB is gonna be my only car till i can get another TII... and then the TII will be the daily driver, FB will be the auto cross project car lol... theres nothing cooler about carb's, unless its cool to not atomize fuel well;) lol

hornbm 05-12-05 01:11 AM


Originally Posted by FB II
you could carb it for 600 or less. but it's a tuning nightmare from the beginning. make sure you have a damn wideband if you go carb! dont get a weber either, they stopped making 48's which would be perfect for you setup and it's expensive as hell for the tuning pieces you will need. if you go holley it will be cheaper and easier although some say setting them up is harder. we'll see. honestly, if i could do it all over again tho, i would have gone efi.

When did they stop making 48s??? you talking about the dco dcoe or ida?

wrxracer55 05-12-05 12:01 PM

there is a place that sells weber style throttle bodies, it is www.twminduction.com. I want that setup.

drunkclever 05-12-05 12:07 PM

in reguards to http://toyotaperformance.com/surge_tank.htm

whats is the efi pump? is that something that comes in the engine all-ready? At work I am going to make a surge tank just like the one in the description. I hope they got more metal in. I am thinking of adding sometype of air bleeder on the top of the surge tank so that I can release any air build-up that might accumulate.

as for the rest..
I am going to order MSD -2225 and Aeromotive A1000-6. I am going to try and go with the stock system for now, meaning I am going to the boneyard this weedend to hopefully find a door. while I am there I am going to try and find a -se wireing harndess(the inside one) and also a stock computer. If I can not find them, I will get the megasquirt.

Elysian 05-12-05 12:59 PM

air bleed? i don't think thats a good idea... as for efi pump, that means fuel pump... u need one for EFI, carb fuel pumps don't push enough psi, as has been stated inthis thread probly 5 times on every page...

GTRay 05-12-05 01:06 PM

the EFI pump is simply the high pressure fuel pump for the EFI system. also, make sure you get an EFI fuel pressure gauge so you can accurately set the pressure of the system.

i would advise against building in the air vent into the surge tank. an air vent is going to allow fuel vapors to escape the system - you don't want this to happen, especially mounted under the hood. any air in the system will be returned to the fuel tank via the return line. if the tank is constructed properly then there will no worries of airation.

in this case i would reccomend building your tank to slightly larger than the specs on that site. the extra capacity will come in handy when the accelleration loads of the 13B outstrip the fuel flow capacity of the stock fuel pump that was designed for a carbed 12A.

before you order any parts do me a favor and give me a complete catalogue of parts that you already have and that you plan to acquire. the last thing you want to do is buy parts that you don't need or can't use.

Ray

tasty danish 05-13-05 01:37 AM


Originally Posted by Elysian
maybe u don't drive ur car every day, my FB is gonna be my only car till i can get another TII... and then the TII will be the daily driver, FB will be the auto cross project car lol... theres nothing cooler about carb's, unless its cool to not atomize fuel well;) lol

dude, there is nothing cooler than having 2 sidedraft horns grinning at you.
i simply feel my project to be a excercise in the utmost simplicity. there is something beautiful about having no electronics and only 1 or 2 lines to clutter the place up. :boink:

Elysian 05-13-05 07:54 AM


Originally Posted by tasty danish
dude, there is nothing cooler than having 2 sidedraft horns grinning at you.

u can have that with FI;)

muythaibxr 05-13-05 08:08 AM

I'd like to jump in and say the megasquirt is a good option... the megasquirt itself, w/o the stimulator, is only about $140 for a kit, or $300ish pre-built. Setup is well documented, and the tuning instructions on the megasquirt site are written as if the person reading has never tuned anything before... so if you've never done this before, there is nothing to worry about.

I'm helping my friend (Tofuball) megasquirt his 13b 6port (s5). We're using the msns-extra firmware on the megasquirt, and a techedge wideband. We're using AFR tables, letting the megasquirt control ignition (right now with a hack-job GM HEI ignitor and the stock leading coil, but after tomorrow, we'll be using a stock CAS, and stock leading coil, with trailing coming in a few weeks), megasquirt controls the aux ports, and VDI as well. We're also using the staged-injection code to handle engaging the secondary injectors... ALL of it works great, so far... and we've revved up to 9000 rpms at full throttle with no problems (well, the HEI module fried but that's the HEI modules fault, not the megasquirt's, and we won't have to worry about that once we move to a fully stock ignition).

Anyway, my point is that several people have the megasquirt running their 13b's without problems.


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