TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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Sweet. RBob is the man. I will probably be giving this a try, with a 4bbl unit, and a couple of superchargers, and see what happens. I just need more money, and more time. LOL
MM no longer sells it (Gen 1 engine with dual TBI, blower, atop a 502) but the above is the cached page showing the same detail. I've posted this info before on TGO (do a search)....... but I needed to repost given the recent (now locked) posts. FYI.
Yah, I talked to RBob about this a while back. Lots of features and is definatly what I'm going to be using on my Crossfire Injection...after the mods and getting everything back together
If this is 'common' knowledge, please forgive my ignorance. But, where do you get a throttle body with four injectors? I had no idea that anyone made such a thing. Why isn't everybody using them?
Also, how would you run (2) two-barrel throttle bodies? Maybe, using a dual-carb intake manifold? How would you set up the linkage?
One final question. I am running (L31) Vortec heads. I don't ever recall seeing a dual-carb manifold that works with the Vortecs. Does someone make them?
If this is 'common' knowledge, please forgive my ignorance. But, where do you get a throttle body with four injectors? I had no idea that anyone made such a thing. Why isn't everybody using them?
Also, how would you run (2) two-barrel throttle bodies? Maybe, using a dual-carb intake manifold? How would you set up the linkage?
One final question. I am running (L31) Vortec heads. I don't ever recall seeing a dual-carb manifold that works with the Vortecs. Does someone make them?
They made approx 390 fwhp using the Holley 4v TBI unit in a comparo test against a PFI setup and a Stealthram. They probably handicapped the TBI test by using the smaller throttle body (700 cfm) than the ones used on the other two engine tests.
OK. Well I found a 4-bbl Commander 950 system on the website. But, it is a system with its own computer. Do you need the Holley computer plus the new EBL computer? Or does the new EBL computer replace the Holley computer?
Again, why isn't this the 'automatic' upgrade to every TBI owner (kind of like an open elememt filter)?
It's not an 'automatic' upgrade because of the cost. Air filter mods are easy/cheap, so nearly everyone does one.
The Holley system is also more of a plug-n-play upgrade, rather than a cheaper DIY mod. Serious money spent on an upgraded TBI could also be spent on a newer car (LT1, LS1 etc).....
OK. Well I found a 4-bbl Commander 950 system on the website. But, it is a system with its own computer. Do you need the Holley computer plus the new EBL computer? Or does the new EBL computer replace the Holley computer?
Again, why isn't this the 'automatic' upgrade to every TBI owner (kind of like an open elememt filter)?
You can get the TBI by itself.
The 2-bbl TBI isn't even a restriction until around 320 FWHP.
Please bear with me. I am very interested in the possibilty of going to this 4-bbl unit. Can someone tell me exactly what is involved in making this change? I understand that I will need the 4-bbl unit, a new intake, and of course the EBL computer. Exactly what else is involved? Are the fuel lines the same? What about throttle linkage? Is the process 'bolt-on' or is highly custom? I saw that the Holley kit (the one that includes the computer) came with a lot of accessories like a new wiring harness. If you just get the TBI unit what else do you need to get to make it work?
The Holley 4bbl TBI unit hasn't been used much as no OEM ECM could properly drive the 4 injectors. It could be used with the Cmdr 950 but that drove the cost up even further.
With the EBL and the 4 injector modificaiton it is now possible to use either the Holley 4bbl TBI unit. Or use two 2bbl GM TBI units on a dual quad manifold.
I haven't looked for any dual quad manifolds for the Vortec heads. So I don't know if any are available.
If you shop for a used Holley unit (2 or 4 bbl) avoid those units that have the black plastic round caps over the injectors. The good units have the newer style injectors with connectors that protrude horizontally from the injector.
Please bear with me. I am very interested in the possibilty of going to this 4-bbl unit. Can someone tell me exactly what is involved in making this change? I understand that I will need the 4-bbl unit, a new intake, and of course the EBL computer. Exactly what else is involved? Are the fuel lines the same? What about throttle linkage? Is the process 'bolt-on' or is highly custom? I saw that the Holley kit (the one that includes the computer) came with a lot of accessories like a new wiring harness. If you just get the TBI unit what else do you need to get to make it work?
The TBI unit has 1/4" NPT openings for the fuel in/out. I believe it comes with barbed fittings for these connections. Can also use a 1/4" NPT to -6 AN adaptor and use AN lines. They are not in the exact same location as the stock stuff, so some changes will be required.
The IAC uses the flat 4 connector (instead of the square 4 connector). So you may need to either get an adpator or cut and splice in the flat 4 connector (used on BBC TBI units).
The TPS uses the flat 3 connector same as stock.
For connecting the injectors I don't know if they have an adpator harness or not. The connectors are different then the stock stuff. Or maybe the TBI unit comes with connectors on pigtails. Either way just need to splice the connectors into the existing harness.
I am not sure about the throttle linkage. The one I have has been modified, so I'm not sure of what is stock. I would imagine that it would be similar to what Holley does with their 4bbl carb's. I would place the installation between a bolt on and custom. Some changes will be required, but nothing that requires a machine shop.
RBob ........... Awesome. Thank you. I have been looking at the Holley website further. The kit comes with an external-tank fuel pump, Oxygen sensor, MAP sensor, and Coolant Temperature sensor. Are these needed? BTW, I already have the in-tank 255l/hr fuel pump. The instructions for the system also state that the transmission will have to be changed from an electronic lock-up to a mechanical lock-up. What is this about? If you splice the connectors for the injectors into the stock connector (or use an adapter if available) doesn't that mean that all of the injectors will fire at the same time? It looks like the 'Commander' system fires them progressively (kind of like the secondaries on a carb). Again, please forgive me if I am asking what some people might think as being stupid questions. Thanks again.
Your making it a bit too complicated for yourself. The EBL with the injector driver upgrade is an add on to your oem computer, with that you can just bolt on the 4-barrel unit and wire up the extra injectors. You won't be using anything from the holley kit other than the TB itself.
I love the idea, because I am debating about building a nice little 355 next year or so. What Id like to know is, can you use the 4bbl, on a 2 bbl, till your ready to step up to a 4bbl? I am trying to get the EBL by spring of next year, and start tuning. And if Im going to build another engine, it is gonna be above 400 hp, which is out of the range of my TB. I just need to practice tuning, on my L03, till Im ready to install the 355. Can I use the 4 injector EBL, with a 2 injector TB, till I get ready to step up?
One final question. I am running (L31) Vortec heads. I don't ever recall seeing a dual-carb manifold that works with the Vortecs. Does someone make them?
BMmonteSS ....... Thank You! Along with RBob, you guys always provide me with the answers that I need.
Quote:
Originally Posted by DLV555
Edelbrock P/N 5426 or 7526 (Air-Gap)
Summit has them listed for Vortec heads.
I don't think the #5426 will work because of the style of plenum opening. I can't find a picture of the #7526. But since they are both #**26 models, I will assume that they are the same. I think #75** just designates the 'Air-Gap' series. Besides that, I believe that the Holley 4-bbl unit is the better alternative and it only requires a standard, single-carb intake. Thanks for the input, though.
Can I use the 4 injector EBL, with a 2 injector TB, till I get ready to step up?
Yes, it will work. Although it is not the ideal situation. The injectors will have twice the current flow during open time.
Quote:
Originally Posted by fadetoblack
. . .doesn't that mean that all of the injectors will fire at the same time?
The injectors will fire in pairs. The wiring is such that 2 injectors are wired in parallel to one driver, with the other 2 injectors wired in parallel to the other driver. Each pair then firing alternately.
Yes, RBob and his buds have made the dream in my previous "Dual TBI" posts a reality. With the EBL, I imagine, you could build a mild 305/350 and run two stock/near stock TBIs complete with an old 2X4 air cleaner for a sweet old school look. Hell, with the EBL and two Ultimate TBIs you could service a big-inch motor, too! Very nice.
This is all great news.
RBob, I've got a few questions for you.
I've heard that it's nearly impossible to tune for a large cam using the stock ecm. Does the EBL system solve this?
Can you give us the details of your engine? Or anyone else that is running your 4 injector set-up? (I'm curious to see actual results.)
I should probably first ask what is a large cam. I'm running a 327 with an Isky cam: 224° @ .050, .465 lift, 108 LDA. Fair amount of overlap. Runs like a dream, no, I wasn't able to get decent results with the stock ECM code.
Runs great with the EBL setup. Which is an offspring of code development & tuning for the 327.
I know of others that are running larger cams & the EBL with success.
Do you have dyno and/or track #'s for your set-up? What size injectors are you running?
I've been trying to get to a track this year. Just way too much rain. This car wasn't built as a track car, but I'm willing to give it a go. Once I do I'll post the results.
As for injector/TBI setup. It currently has the 2bbl TBI on it. Punched out to 2-1/16" bores, with 81 #/hr injectors at 22 psi. At that pressure they are flowing 112 #/hr each (using 11.5 psi as the 81 #/hr rate).
I recently went back to using the vacuum adjustable fuel pressure regulator (VAFPR). This works out great. In testing the EBL code I keep switching from one setup to another. Once back to the VAFPR I was happy with the results. It makes a world of difference.
FWIW Dan, I have a Vortec 330/350 motor, with 9.75:1 compression, comp XFI cam, the EBL and a BBC tb, VAFPR topped at 26 psi. Desktop dyno gives me over 350 horse, and 420 lb/ft of torque. In a few weeks I am taking to the track. With the EBL performance data, I should run a high 13/ very low 14 without the NOS. I also have a 250 horse NOS cheater kit on the car, with the 120 horse jets. All controlled by the EBL. Including fans, shift light. Before I go to the track I am gonna borrow a friends G-tech and see what that says. But, the track will tell the truth!!
The EBL looks great. I couldn't find much information about it when I searched the TBI boards, but I found a ton of info in the DIY Prom boards.
I'm really liking the idea of running two stock tbi units, on a dual quad intake. It seems that this could be done a lot cheaper than the cost of the Holley 4bbl unit. Would there be any drawbacks to this that I'm not thinking of? How much power could this set-up support?
