Thread: Which Fuel Inj. to buy...

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im looking to replace my 6-71 blower with a EFI unit as well and I cant decide what to go with. all the throttle body units look pretty lame so im curious to see what people will say here =).

Originally Posted by Uptown83

im looking to replace my 6-71 blower with a EFI unit as well and I cant decide what to go with. all the throttle body units look pretty lame so im curious to see what people will say here =).

Check these cool kits out for Chevy and Ford
http://www.twminduction.com/v8_kits/chevy.html

Originally Posted by hcar

Check these cool kits out for Chevy and Ford
http://www.twminduction.com/v8_kits/chevy.html

They are cool looking.

My main concern will be the items in the bulleted list I started with. In particular driveability: which would include good support and information for setup and tuning, etc. I feel pretty good with support I've gotten from Holley in the past. If I go with someone like TWI...I'll have to become comfortable I'll get teh support I'll need.

Any input on that for this company?

Still awaiting thoughts on the original question.

Originally Posted by Uptown83

im looking to replace my 6-71 blower with a EFI unit as well and I cant decide what to go with. all the throttle body units look pretty lame so im curious to see what people will say here =).

I'll bet we miss the push back in the seat that the blower delivers

But we'll probably enjoy the improved driveablity and economy

Originally Posted by ewingr

I'll bet we miss the push back in the seat that the blower delivers

But we'll probably enjoy the improved driveablity and economy

there tech is good and I can tell you Roush Performance buys these kits and puts them on there 402IR motor, this is modern tech.
http://www.roushperf.com/pdfs/402IR.pdf

hcar, the stack injection looks really nice but does have some problems with initial setup and holding adjustment for the long term. I have $5200 in ours so far so it isnt a cheap solution.

Throttle body injection (TBI) is a poor man's fuel injection. The GM version runs 14 or so psi and squirts into the throttle body so there arent 8 injectors. The TBI is kinda half way between a carb and fuel injection. Positives: cheap, simple, can cobble one up using stock parts. Cons: not as fuel efficient as real injection, uglier than a pig, not very tuneable

Fuel Injection runs >40 psi and can be either a factory job or an aftermarket unit. The common factory jobs for the SBC are the tuned port and the ramjet. The tuned ports are cheap now, a lot of people hack the code so the controller is easy. Parts (sensors) are at the Chev dealer. The ramjet uses a Mercury Marine controller (MEFI4) and is similar looking to the old Rochester units from the 50's and 60's. Arizona Speed and Marine sells a unit similar to the GM unit. Both work really well at lower revs (5500 and under).

After market units seem to be everywhere now. If you go this route, make sure that the unit has oxygen feedback (O2 sensor). Most of the units that feature "no computer" adjustablility are pretty limited in their abilities and are pretty crude controllers. A good controller vendor will recommend your cam basics, ask a bunch of questions about your motor, and will program the controller for your application.

Expect to spend at least $2K for a respectable setup or up to $6K for something like the Roush stack injection.

Injection is really nice for street vehicles.
mike in tucson

Robot

Do you know of any comparison information on varying systems? I was thinking of the Holley Stealth Ram. I know it does have computer programming (I'm not knowledgeable enough to know much about how goot it is) and has 0xygen support.

If I start getting towrad 6K, I would rather sell my engine with the blower and put in an LS1. It would ultimately cost me more than 6K, BUT 6k would be a good start on it.

Originally Posted by hcar

there tech is good and I can tell you Roush Performance buys these kits and puts them on there 402IR motor, this is modern tech.
http://www.roushperf.com/pdfs/402IR.pdf

I get an error that the PDf is damaged. I'll try again later.

I did a little more browsing, and it looks like they don't sell the computer stuff. That means purchasing from multiple vendors. That scares me more.

And, if I get up to 5K or more, I will probably go with an LS1, as I noted above.

ewingr

Fuel Injection Specialties is in San Antone, their web site gives a good summary of Tuned Port Injection:
http://www.fuelinjection.com/

Arizona Speed and Marine: http://www.azspeed-marine.com/

Street and Performance: http://www.hotrodlane.cc/

I would suggest that you find a source that sells you the entire unit including the controller. Then, you will avoid the finger pointing if something doesnt jive. Next, decide what your intent is going to be, looks, performance, economy, simplicity, whatever. Talk to a couple of vendors and dont buy until you talk to your chosen group.....most will say, "we'll fix you right up" but spend some time and learn the basics. Also, if you can find some local guys who have F.I., you can talk to them....especially about a vendor's tech help after the sale. Also, if you dont speak it yet, get up to speed on the lingo..... CPK, VSS, etc....just like computer nerds, the injection world has acronyms to make them feel special.

Next, when you have knowledge of the systems, assess your engine. Do you already have a crank sensor and a distributor that is setup for your chosen controller? Note that most higher-end controllers tie the ignition to the fuel.
For instance, AZ Speed and Marine builds a MSD air meter on a GMPP manifold with the injector bungs welded in. A MSD distributor is tied to the Mercury Marine controller. They sell the harness and everything. When done, it looks like a carbureted setup except for the fuel rails. We put one together, set the static timing, and it fired first lick. Most of the better sources sell very high quality harnesses with the good wire. Most of the injection systems use factory type sensors.

Once you have done one, you will enjoy the easy starting, smoother performance and other advantages of injection. Unless I was building a drag car, I would never go back to a carburetor.

mike in tucson