How simple/complicated is to install a 900cfm stand alone 4BBL-TBI unit in a moded 305? I will be buying one very soon...(already have 4bbl intake)

Stock TBI not enough(even moded); 670cfm only fits cars up to 89(unless u want to run in open loop) and I have a 92, see why I need the stand alone system? Im trying to take a 305 all the way.
Sorry, no 350's,superchargers,TPI's,nos,or carbs.

 

Wow, somebody should have told me that I can't run the 670cfm unit cause my car is a 91!
Yo, no reason why the 670cfm unit won't work. If you plan on going with a stand alone system (scrapping the GM ecm) then go with the holley 950 system because it can control the 4 peak and hold injectors found on their 4 barrel units. The GM ecm can't control anything more than 2 unless you think the car will run fine with half the voltage going to the injectors .
I can't figure out a way to run EFI, a 305, and require anything more than the Holley 670 unit. Do you mind telling use how much power this 305 is making and what heads/cam combo!

 

yeah if your name is what ya got "335" id too like to know if that stroker kit helped alot and what your runnin quarter wise as well as maybe streetability.

 

I would like to think that the technical advisors at Summit,Jeg's and Holley themselves know what they are talking about. I will not lie the car is not build yet but I will start the build up by the end of this month. I do have most of the parts already and this is how it goes good or not.

Deluxe(best parts) Stroker kit .30 over,new roller lifters,new hex true roller 2xroller timing chain($120),Crane Powermax 222/230---.509"/.528" roller cam,Sportsman II heads milled to 58cc 200cc runners including 10 degree locks and Titanium retainers to avoid valve float,1.6 T6aluminun rockers with girdles. Single plane Xcelerator 4bbl intake(IN NEED OF FUEL DELIVERY SYSTEM-HOPEFULY THE COMMANDER 950-900CFM FROM HOLLEY). Complete gasket set and the intake-block-heads-headers,gaskets will be sent to be port matched.

Complete March pulley set and brackets,new alt,new TCI starter,new optima battery in the trunk,double pusher fans,HI vol. oil pump,300+ Accel ignition system, billet breakerless distributor,no cat,no stat,completely no emmision system,headers,silencer and cut-out,aluminum drive shaft + yoke,3000+ stall converter,upgraded racing tranny(check "Transmissioncenter.net")pro series auburn posi,Richmond 3.73 gears,full racing suspension(sub frames included), fiberglasss cowl induction hood,B&M megashifter,digital air/fuel ratio gauge,vented rotors,stock but chrome aluminum rims,drag radials,and a whole lot of chrome and a few more goodies...
Everything is brand new and If new engines kick *** my little 305 will trully surprise many, I know.

 

I have no doubt that your setup wont be nice, it sure sounds like you plan on getting the most outa that 305.

However, we have several memebers running the 670 on 89+ cars. JPrevost and NJ SPEEDER come to mind right away.

And the techs at jegs/summit - in my expirence - dont know jack about TBI. Hell, lots of efi guys dont know jack about tbi. I really dont know a lot about it and I've been reading all the stuff I could about it for the last 3 years.

Holley is just saying that it wont work so you'll buy their 4bbl unit which is like $600 more.

 

I don't mind using the extra 2 injectors been that they are fully adjustable.

 

That 900 CFM tbi unit has 4 85 lb/hr injectors. WAY too much for your engine. You will never get it to idle. Get either the 650 or 700 CFM units that have either 45 or 65 lb/hr injectors.

 

"The GM ecm can't control anything more than 2 unless you think the car will run fine with half the voltage going to the injectors ."


Not that id actually do this ( i think the 670 is more apropreate), but couldnt you just build an external cotrol box w/ transisters (and some other stuff) working as solid state switch to trigger teh injecters from the computers signal? i would think that each bank of two injecters could be run in parrelel from the one signal fromt the computer for each stock injector.

 

Yes Doug, maybe ur right, 900cfm is somewhat too much so I should go with the 700cfm unit (spacer if needed)plus I love the square flange as far as breathing is concerned compared to the 670cfm (2bbl)satand alone system.

As far as fitting a 670cfm into the 89 up camaros, If it's the truck TBI u may run into some type of problem but not with the 2bbl 670cfm stand alone system. Besides I want to believe that my 305 will make a little more HP than the 300 max. limit the 670cfm unit is supposedly capable of handling.

I MUST build a strong performer cause there are a few races that will take place soon and many people are betting against me and making fun of my car CAUSE IS A 305, I love to prove people wrong especially when they are so sure about something. I will be racing a couple of mustangs but there is a guy with an RX7 20B turbo modified engine that says no way in hell do I have a chance on beatting him and he really mean it. We'll see about that. If u guys want to see the race I'll uploaded cause I will surely have it recorded. Thanks Doug.

 

Well considering the stock unit has supported 300hp I don't see how the 670cfm unit only supports 300hp. I've figured that with GM BBC 90gph injectors I should be able to support over 400hp with this 670 unit, and there are no problems getting this to work on a 91 f-body. The only "hassle" might be the TPS sensor but $2 in the parts store will get you the weather pack required. The 90-92 TPS sensor has a funky triangle shape and the holley unit is 3 in a line, if that's too hard to figure out then don't even bother spending money on the 305...you've got a lot more complicated obsticles ahead like valve shrouding from the small bore.
Cam selection is going to be the biggest headache and I'll bet money that it won't be TBI friendly. You'll most likely convert to an Alpha N system to make huge horsepower and keep EFI. I just can't imagine a good vacuum signal with a cam that'll suport your expectations and remain n/a.

 

Actually, i may give this a try. The external control box could simply be a set of voltage followers made w/ op-amps. Very cheap and easy. Of course, a transistor circuit couldn't hurt, but would take a few more calculations.

 

2 things that might help you:

 

other:

 

Putting that up there is like hyroglyphics to me! But since im just in this thread for the knowledge i dont guess that matters. What about that TB from turbo city? Does is look like it would be worth it? I plan on around 300 hp when im through with the rebuild but then soon after i wanna add the pc1 procharger(forged internals of course) so i just wonder if that TB is gonna support that.

Brandon

 

Your doing a lot to that 305! It should be sweet. As far as the injection goes, the holley 670 WILL bolt right up, with only a small amount of wire spicing (very easy). I have a '90 and it works like a charm. and as far as hp rating goes, the 670 is capable of handling quite a bit more than 300hp. A stock unit with a few mods can do that (though it is it's limit). Being a TBI owner and on this bourd I almost hate to say it, but if your spending the money, why not think about ram jet or tpi. Or even carb. The tpi and ram jet will be more expensive, but there also a sure bet in meating your hp needs. Just my $.02, please don't hate

 

heh... i went with mechanical enineering three years ago instead (ah... descisions, descisions).... so im only slightly familiar with schematics and design of circuits. Ill keep those in mind, though...

 

question, is teh activation signal for the injectors just a step (on/off) type of deal or is it something else?

 

keep in mind that the bores are small and once the flow through them goes sonic (b/c of your power adder) You cant get any more air flow rate, no matter how much you increase the boost. I think i calculated out the theoretical maximum at something like 1200 CFMs. (Very, very theoretical)

 

It's a little more complicated than just a switching transistor...it seems to have very specific timing controls. I hope Grumpy chimes in because I always thought I'd just install some heafty transistors from an old amp and run it like that. I don't see how it's any different but obviously it is or they wouldn't have made such complicated schimatics .

 

the TBI injectors are low impedance and thus require a peak and hold type controller. the 'complicated' schematic shown converts the peak and hold signals from the ECM to digital signals which then drive 4 individual peak and hold circuits. This prevents low voltage to the injectors, provides the right power handling for the transistors, and provides the peak and hold function. The peak and hold more or less saves power and extends the life of the injectors. it takes about 4 amps to open the injector soleniod, but once it's open, it only needs like 1 amp to keep it open, thats why it is designed that way. I built this 'translator' and bench tested it, but I have yet to install it on my project. Hope that clears up why you need a special driver for low impedance injectors.

 

for somebody with sooooo much $$ to spend "by the end of this month" on a 305, you wana build the first 2.25 inch 2bbl tbi and run some 80pph injectors at 20psi? see pic under my name

edit forgot this

however, good thread on running the 4 injectors off gm ecm.

 

Thank you JPrevost. Do you happen know what kind of current those injectors require (so I can pick the right transistor)?
I would like to give this a try some time this summer. But, rather than using a four barrel TBI unit, I want to use dual stock two barrel units (for money reasons, I can get a used TBI cheap, and a dual 4 barrel intake. Then i'd just have to make the TBI - 4barrel mounting plate and some kind of fuel manifold or splitter). Hmm, i wonder if this would clear my hood.
This idea probably sounds dumb to most ppl, but hey, it's different .

 

Never mind the current thing, I just read the above post

 

of coarse, by adding all this extra stuff mentioned in the posts, it seems to defeat the efi's main strenths of simplicity, realiability, and ease of use... but thats just my opinion.

 

tag

 

The CS 452s, and LM1949s have long since been discontinued.

The only answer now adays for the DIYer is going with some LARGE, POWER MOSFETS. You just going to have to run them in a saturated type mode. You can use a 555 and then cut back on the power using a second MOSFET, but it gets ugly to do that.

As for the 670 not working on something, here's a head scratcher.

670 TBI with a custom adapter mounted on a XFire.

Yes, it runs just fine thank you very much.....

 

Grumpy, is the following link out dated?
http://www.national.com/pf/LM/LM1949.html
Also would it be too difficult to grab some "fried" ecms and desolder their LM1949's? Maybe take them off some TBI v6 ecms that are a dime a dozen.
If not, do you know if there are any plans for your alternative method in the diy-efi.org ftp incoming folder?
Thanks

 

Soon there will be an "in your face" follow me If u can video showing a monster asphalt ripping 305 here. Jprevost I think u don't know much about 305's or hate my mods too much considering ur comments, and the current parts available for my car. Have u open up a magazine lately prevost?

Just cause some of u don't care or can't afford to modified a 305 does not mean I should do the same; frankly I have seen 350 et's on a few F.Body sites and they suck. 12's 13's a few 11's hahahahaha even supercharged.

YES I WILL BE FASTER and by the way remember there will be a video don't be laughing or pulling bs flags too soon u may end up eatting them.

 

considering that a 305 isnt too far away from a 350 in terms of ci thats more than possible given $xxxx to spend. It would probably be more cost efficent to buy a built 383 and put TPI on it. If doing your own custom build is the kind of thing that turns you on, then by all means, go ahead.

 

Id be happy with a low 13 or high 12 when i get my 350 in.

 

Sounds like you want to get flamed. No where have I denounced your mods, I've only pointed out some very serious considerations that you'll have to take into consideration!
You're wrong all over, I know plenty about 305's, more than you but I'm not going to get into a pissing contest on the board. As for the mods, if I hated them why would I be posting information that should be HELPING you? Don't want the plans for running a 4 barrel TBI off of a GM_ecm, fine, tell me to take the images off this topic :duh:. Now what kind of a stupid question is "have you open[ed] up a magazine lately"...I've read plenty but I don't usually "read" magazines, I just like the pictures . Seriously though, don't go by what magazines tell you unless they display baselines or have a HUGE article with good sources listed. When was the last time they talked about TBI, my point exactly, they don't know everything and they never will. Personally I'd rather read my ASE books, much more information and less .
I'd love for you to make me eat my words because I've been around long enough to know that most of the new guys to this board talk but don't walk, in other words, "yeah, I'm getting a blah blah" and next thing you know they sold it, wrecked it, couldn't afford it, disapear/never heard from again, or do the mods and are so disapointed that they give up and sell the car or slap in a 350/383/400 Etc.
I have one last thing to say. NOBODY I've talked to has ever been disapointed with swapping a 350 yet everybody that's rebuilt/built a 305 gets a bad case of the speed itch!
Now if you're serious and can tell me your budget I can be a very helpful person but if you don't want my help just let me know ahead of time so I don't have to waste anymore time on this topic.

 

i used to be like this guy. when i was a newbie, um was that 4 years ago now. Wow how time flies. i had big dreams for my 305. then i realized that 10 thousand dollars on an engine was retarded.

dont get me wrong now i still have big dreams, but they are for my 69 camaro. and 10 thou on that is not retarded.

the in your face video will never come. let me know you are over 19 and i might start to beleive you a little. or how about some other history of other engines you have built, because if a monster 335 is going to be your first. good luck tuning that 4bbl tbi, you better switch to carb fast. LOL

the topic here was great... until we got another response of in your face... Jon, how about we change the topic, and keep the good info up on this post.

nic

 

I tired calling around some time ago, everthing even related to injectors are gone. Once accel, holley, etc etc heard they were going to be discontinued, they bought up all the remaining stock of them.

We'll just say, I tried to test a POWER MOSFET'd ecm to distruction, and failed. While they waste some electricity, and generate some extra heat, it did last.

Might be time for a processor fan thou.

Someone just needs to pick up the ball and continue with this.

 

I'm open (for the pass )!
What about just snaging some ecms from the junkyard that are "broke" and just remove their injector driver circuits?

 

I'm open as well
I may play around with this idea at the lab at work tuesday, after my microprocessor project for class is finshed. I'm only an undergraduate, so I'm still kind of new to this, so i'm open to any suggestions.

 

Hey Im not going to justify myself prevost and please don't let ur emotions run wild is not healthy; but understand me eversince I started buying parts for my car since last summer all I hear for the most part is how ****ty my car will be and Im fed up with it specially when it comes from people that have not given the 305 the mods it really needs to perform at its fullest. Yes it takes more $xxx to build a 305 unlike a 350 for speed but a 305 just doesn't accept a half way job. Prevost Im not sure but I think that the 4bbl system comes with all u need for easy installation, what I need to find out is how simple/complicated is the actual installation from someone that is done it------Exactly my point!!!!!.


Im 33 years old on a budget but with some $xxx to play. I don't BS no time for that and if my car ends up slow(not likely) ur damn right I would sell it or buy a 350 crate and switch as many parts as i could to it. As far as the video, please there is nothing to it, it will be posted fast, slow or whatever just to show that I walk the walk.

 

no offence... but if your doing this to prove everyone else wrong, then your doing it for all the wrong reasons... my bro had four f bods and he learned the hard way that its cheaper just to put more displacement in rather than mod the two 305's that he had. He quickly adopted the "more ci's is better" attidude and just droped a 400 in one and a 350 in the other. Im going to follow his example and just put a 350 in.

Back to this injector topic... When i get some more free time im definatly gonna construct one of those controller circuits. Probably wont find a use for it but what the he!!, itll be a learning experiance.

 

335

Newbie's a little uptight huh?

Coming back at people is no way to get good info.

Unless you beleive what you read in the mag's. The only thing that the "talking heads" (where did I hear that before? LOL) know is what the people who's parts they are trying to sell tells them for the most part.

And.... the "tech advisors" as you call them. It really makes one wonder after talking to some of them and you knew more before you called

Sorry Tas....it spontaniously combusted or something like that!!!

 

Obviously noone so far is given me a straight answer and all I feel is a lot of hate. For those that complimented what Im about to do to my car thank you. Im done here, LIKE A SAID, NO TIME FOR BS!! however, we will pick this up in a couple of months.

 

If you feel anything it's just what your attaching to it.
The Net is rather poor form of communication. There is no vocal or visual aids to what's being said.

If you want to play with a 305, more power to you.

If you want to go fast, you can reinvent the wheel or use proven ideas. Some of us have build engines for more years then you've been alive if you want to raise the age issue.

You might want to research bore to stroke ratios.
And then valve diam sum to bore ratios.
then rod lenght to stroke ratios.
Once you get past understanding things like rod lenght and cylinder filling you'll have a firm grasp on what the 305 is designed to do, and the 302, 307, 350, and 400. There is alot of genius in these engine series.

Every engine has it's inherit good traits and flaws.

You want to ignore all that fine.
HTH

 

Cheaper to buy some off the rack stuff and start that way.
For 4 P+Hs you'd need 2, 747s.
The few CS 452 I bought years ago were $4 a pop. Can you buy 2 747s for $16?.

Remind me off list in a day or two if I don't post a part no., but I think I have a current MOSFET number around here.

Don't be surprise thou of an EE going that won't work.....

 

Aaaaamen brotha. :sillylol:

 

Hey 335 that setup will be sweet i love my 305 and im looking at preety much the same buildup that ur planning on doing. but all i gotta say is that you will lose to the RX-7 no doubt... 20B with turbo hell he has u beat. 13b's come stock with 2-rotors and the 20B comes with 3 rotors thats like taking a V6 and making it a V9 speaking in relative terms. the 20B's run at 350-400 hp out of the box properly modified by the rotary motor builders. then with turbo hell he is gunna leav u at the line. i love camaros but i wanted an RX-7 its the only import i'd buy. So i read up on all the mods and found out how they work and are built. they arent reliable but the are quick and powerful. ID LIKE TO SEE THAT RACE. what yr RX-7 is it and does it have turbo?
.

 

I'll answer your question since no one else has.

I went from the stock ECM 2 bbl TBI to Holley Projection 4Di. (4 bbl 900 cfm) The install is pretty straightfoward. It comes with all new sensors, harness, fuel pump, and ECM. I strongly recommend the Di system for it's laptop tuneability. I find this to be a major plus to the system since you're not pulling the ecm apart all the time to "burn" new proms.

For a neater appearance I stripped my Factory harness of all the abandoned wires from the old ECM. The trick is to label all the old sensor fittings (tape and a marker) the harness leads from the firewall thru the wheel well and under the dash to the ecm. I mounted the Holley ECM in the "stock" location. (Bend one flange 90* and the bolt holes line up like it was "meant" to go where the factory ecm was.) You will figure it out as you start to work on it, just take your time, this is a weekend job.

From what I know the NEW Holley Comander 950 is a multipoint system not TBI.

TBI's are not vacuum signal sensitive like a Carb, but
The 900 cfm might be too large for the 305 (335) unless you plan on spinning way past 7000+ rpm and making over 500 horse. You could adjust the injection volume curve and fuel pressure to compensate but you can only take some much out... The 700 cfm will be just right.

Depending on how radical a cam you select you will need a vacuum canister to run power brakes Also be sure when you order headers you get them with O2 sensor bungs installed.

Good Luck.

I need to get my car ready for Gateway, who's heading out on the 27th & 28th?

 

You lost me when you said TBI's are not vacuum signal sensitive like a carb....it's the other way around. TBI is speed density EFI, it requires a solid reliable manifold pressure (vacuum) reading at the TB or it won't be street friendly. This is why I told him to go with an alpha N EFI system instead of the holley commander and gm-ecm!!! Alpha N systems don't use a map sensor, they just look at TPS position, engine speed and vehicle speed. Some look at coolant temp and intake air temp but you have to look around. The advantage of these systems is that they don't care what kind of cam you have in the engine.
This is extreamely useful information but if you want to disregard it because I "hate 305's" fine, I'm done.

 

FRMULA- thanks for bringing this back on topic-although the original poster jumped on prevost for appareantly no reason. I'm not taking sides-just call it like I sees it.

Your set up may have been a weekend job but that comando is not. I hope you have a daily driver cuz that thing can take a good while to work on a special set up. You will need hours upon hours to program that thing. There are 200 variables to program to make it work

 

All Holley 4 bbl TBI units come with the Commander 950 ECU, as well as all multiport. With aftermarket EFI, I've tuned cars with as low as 5 in Hg of vacuum with speed density. Obviously not daily drivers. I know of tuners that tune speed density less than that.

Just need to tune it correctly.

When sizing TBI, you choose injectors based on engine HP the same as a multiport. The BSFC may be a bit higher with TBI.

 

Doug

Can I upgrade my 4Di ecm to the commander 950???

I have the marine version of the 4Di so there is no knock sensor.

Also if I want to add a supercharger or turbo. will my 4di ecm support a 2 Bar map sensor?

 

PN 950-100 upgrades a 4Di system to a Commander 950. Comes with ECU, Harness, software, and com cable.

The 4Di actually uses a 2 bar MAP sensor. The C950 is selectable for 1, 2, or 3 bar MAP sensors.

Not trying to sell you something, but I'd recommend upgrading the ECU, but you can do it with the 4Di, just takes more time and patience and you don't have as many tuning features.

 

Maybe I should have read more than half the thread, and I'm not knocking anybodies opinions. I don't know everything. But this is how i see it.


Same goes for 300 HP on the stock one (with injectors upgraded).
Can you make 300 hp on it? Sure. Would you see a big increase if you took that same engine and put a 670 on it? I'm pretty sure.

Would the 670 support this engine? Sure. Would he get more power out of the 4 bbl? I'd be willing to bet.

BTW I'd always wondered about injector drivers. I'm gonna have to stare at that schematic for a while. I don't remember where I learned to read those, but i have been able to for a few years at least identify half the stuff. I wish I remember where from. Might give me some crazy ideas.