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Custom 4bbl TBI, what do you think?

muscle

muscle

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Ok guys I posted on here about a week ago about this guy making custom four barrel TBI units. TBI is a much more affordable way to convert a carburated engind to EFI. The problem with tbi is the stock gm throttle bodies are limited to a maximum of 670 CFM (this being the big block gm TBI units).

I have a 400 sm blk that requires a minimum of 750 cfm. I bumped into this guy http://www.customefis.com/index.html on the internet while searching for what I was looking for.

He told me he was building custom four-barrel tbi units as a kit for $1500. He finally sent me some pics that i have included here for your opinion. What do you guys think? is the linkage assembly a little cobbled?

The good thing is that the ball bearings on the throttle shafts. More about it here http://www.customefis.com/pod.html

should I go for it or keep looking?

P1010004.jpg

tbi1.jpg

tbi2.jpg

tbi3.jpg
 
Steering linkage looks aweful. The whole thing looks very 'homebrewed' to me.
Are you sure you need 750cfm + ?? That must be a seriously high reving motor to need all that air?
 
looks a little cheesy, but at the same point, a Holley 4 barrely throttle body costs I believe about $1000 just for the throttle body. The whiteknight is running a 4 barrely TBI setup, search and see who they went through.

Fuel injection usually requires a bigger amount of airflow than a carburated setup. A lot of TPI guys run 1000cfm throttle bodies. But that is TPI, don't think TBI needs it so much.

The increased fuel supply would be a big factor to me with this setup.
 
Why not go Edelbrock EFI? Still under $2K and includes whole system (intake, stand alone comp, injectors, air valve, etc).
 
this one still gets my vote!! :-p

4bblThrottleBody.jpg
 
mini_mull said:
Why not go Edelbrock EFI? Still under $2K and includes whole system (intake, stand alone comp, injectors, air valve, etc).
Click to expand...

Word...go to a junkyard and buy a complete tbi harness, tbi, and computer and sensors for 300 then buy this kit from edelbrock... you'll have mpfi with the simplicity of tbi since it runs off all the old tbi stuff. WAY better than tbi.

http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10002&storeId=10001&categoryId=14297&parentCategoryId=10299&langId=-1
 
one big problem i see with all of these pics posted so far. thay are not t.b.i units. where is the injectors.? thay are just air valves. those need to be used with injectors on the manifold . if you are going to spend that much just get the edelbrock pro flow unit. then you can play with your stuff your self.
 
southernspeed said:
Steering linkage looks aweful. The whole thing looks very 'homebrewed' to me.
Are you sure you need 750cfm + ?? That must be a seriously high reving motor to need all that air?
Click to expand...

I had a 650 cfm edelbrock carb on this motor and it was like you were suffocating it. Im running a 750 holley now and it has its power. But im glad I posted this here because i was thinking his TBI looked a little clunky.

I was hoping to go with a retrofit kit in tbi that could save money, not starve the motor. I guess ill need to look at multi-port like edelbrock or holley. I heard accel makes them too. If you guys have upgraded your engine with one of these id like to hear about it.
 
I'd do some serious reserach on Accel injection stuff before spending some money on it. Their fuel injectors are notoriously horrible out of the box.
 
mini_mull said:
Why not go Edelbrock EFI? Still under $2K and includes whole system (intake, stand alone comp, injectors, air valve, etc).
Click to expand...

gets my vote, I e-mailed them to see if they could help me with my engine and they said that it will support 500hp with 36lb/hr injectors
 
loafer said:
I'm running the Holley Commander system 950 with a 4 brl TBI. So far it's worked well. I bought the 650cfm one for my stock 350, but they sell them up to 900CFM: http://www.holley.com/types.asp?type=61
Click to expand...

Hey loafer how was that to install? The holley kits require a laptop to program, where the edelbrock mpfi come with the calibration module. I am running a weiand 8004 intake which is in the holley family and im sure will be compatible. also i see that holley does not include an upgrade kit for your distributor for timing control. The nice thing about it is the $1479.00 price.
 
muscle said:
Hey loafer how was that to install? The holley kits require a laptop to program, where the edelbrock mpfi come with the calibration module. I am running a weiand 8004 intake which is in the holley family and im sure will be compatible. also i see that holley does not include an upgrade kit for your distributor for timing control. The nice thing about it is the $1479.00 price.
Click to expand...

It does require a laptop to program, but it is much more versatile than the Edelbrock system. it can be set up to run MPI, 2 brl TBI, 4 brl TBI, computer controlled timing, and allows you to run all kinds of different ignition system configurations. You can even run it with a mechancal/vacuum advance distributor, but I don't recomend this as it is very difficult to stabalize the idle. You aslo have full control over the timing map, fuel map, idle air control, acceleration enrichment, and many other useful parameters.

For computer controlled ignition I just bought a used large cap distributor from an EFI 87 (I think) Camaro. These distributors are a direct plug in to the Holley wire harness. You can also use the small cap distributors with a cheap little adapter harness that Holley sell. I made my own adapter harness with the intent of switching to the small cap dist. some day.

I've been having a little trouble with IAC valve sticking lately on mine (3 years old now) but I just ordered a new one, so hopefully that will solve my problem.
 
eagle mark said:
Where are the injectors on that new TBI unit?
Click to expand...

I dunno Mark, but Im leaning now towards an edelbrock mpfi.

What intake do you use for your mpfi? and can I get all the bells and whistles with your system that I can with edelbrock?
 
We use the Holley MPFI intake.

What Edelbrock system are you leaning toward and we will take a look.

I know one advantage we always have is long term proven reliability of GM parts that are NOT special order. Along with the supporting websites and documentation of GM systems.

What's your engine specs?
 
eagle mark said:
We use the Holley MPFI intake.

What Edelbrock system are you leaning toward and we will take a look.

I know one advantage we always have is long term proven reliability of GM parts that are NOT special order. Along with the supporting websites and documentation of GM systems.

What's your engine specs?
Click to expand...

approx 375 hp 400 sbc:

Balanced crank, rods pistons
91/2 to 1 hypereutectic pistons
Hydraulic lifters
Comp Cams - Duration: @ .050 214/224 Lift .443 .465
Stock heads ported, polished 1.95" intake, 1.75" exhaust, roller tip rocker arms.
Weiand 8004 intake, currently with 750 cfm Holley carb.
Exhaust is headers with 2 1/4" flowmaster.

considering the Edelbrock Performer Pro-Flo EFI System or the Performer RPM Pro-Flo EFI System.
 
Your 400 engine is similar to the 383 in the red Camaro on the MPFI page, his is a little bigger cam and does 420hp on the dyno.
http://www.affordable-fuel-injection.com/chevy-mpfi-sbc.htm

Actually with your cam we have run the large bore TBI with great results for half the money. It will not produce the results of MPFI.

I don't know how to compare them as I've never run the Edelbrock system. Ours comes with a new small cap or large cap EFI distributor, theirs does not, I didn't see any mention of a MAP sensor with the Edelbrock but they say it's speed/density? About the same price, we can add a tuner for $395. that is run by laptop and is more a professional level then just pushing buttons on a display. It's also capable of Nitrous tuning. With your engine you won't need any tuning with our system, even if you did the chips are guaranteed!

Reliability and service are a couple things you need to look at if this is not a race car. AFI systems can be serviced by anyone with GM experience including a lot of guys on this board. Parts are easily obtainable at any parts store in the country. If you forget to unplug your ECM and weld? Then need a new ECM, they are to available at the parts store or wrecking yard. The support for GM systems is incredible as you can see the Edelbrock system refers it's ECM to a GM unit.

Hope that helps
 
Hey guys.....
This year we will be running a BBC MPFI system from Affordable Fuel Injection

One thing I can tell you, is these guys have great service and know their stuff and would highly recommend them...

Our first trip this year will be Moab and look forward to testing the changes full out then.....
 
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