As some of yall know I'm purchasing a 350 crate motor when I return from this deployment. I've already got all of the externals needed, along with the 350 esc and knock sensor and Cop chip, but I'm still a little leary about buying the Holley TBI.

I've read the sticky multiple times, and I'm not all about having to weld a bracket so my cruise control works or splicing wires so I can reach the sensor on the side. Also since I'm going to be using the Edelbrock TBI Intake, the 2" bores will not be that great of a benefit.

So I'm thinking of sticking with the stock TBI unit, putting some 65# injectors on it and a TDS afpr and being done with it.

So help a guy out here. This is the last piece of the puzzle before purchasing the motor.

Thanks.

 

So what crate engine are you getting? You could always get a junkyard tbi and have it board out as large as it will go then do the same to your intake. That would help some. Or buy a 454tb off e-bay or wherever, there not as hard to setup to the stock linkage.

Steve

 

This one: http://www.goautocenter.com/300hp_tpi_1987-89.htm

 

Your going to have to run a lot of fp with those 65# injectos to feed that engine but it sounds doable. Still woudn't hurt to bore out a stock tb to get more air though.

Steve

 

22

 

How much do you consider alot? He is only talking about feeding a 300HP motor.

 

Well considering that the stock pressure is 9-13psi and stock hp for a 350 running 65# injectors is about 210hp I'd say he would have to up it to at least 17-20psi, that is almost double what the stock fp is.

Steve

 

210 hp is what the motor is producing, but that is not because of injector size limitations. The formula I have seen used on this board to size injectors was 1/2 pound of fuel per HP. A pair of 65# injectors at stock FP should support 260HP. I estimate that I am sitting at about 300HP with my mods and 65# injectors, with FP set at 15 1/2 lbs. Motor pulls strong to 6000 RPM with no evidence of leaning.

 

Gunny,

You should still consider the holley unit and either boring out your performer tbi intake, or going with another intake.

The main reason people need to fab their own throttle bracket is not do to the holley tbi, but do to adapter plates moving the tbi foward, or if the 300-66 intake is used, it also moves the tbi foward. The only modification to the holley tbi throttle are the studs to which the cables connect, which is easy to do.

If you seriously want to come close to making the 300hp, you are going to need a 2" tbi. If worse comes to worse, having a custom bracket made up should not be all that bad or expensive.

 

Joker, how did you figure your getting close to 300hp from your setup? Do you have track times or dyno printouts. With the mods you have thats pretty impressive.

As far as the fuel presure to get a certain hp from a certain size injector I didn't do the math like I should have. I guess we all get lazy sometimes. I was just implying it would take a lot more than stock. My 91 only had 8psi when I first put on my fp gauge. Now since I have the afpr on it it stays around 12psi. So I guess I was just going from my own experiance.

Steve

 

The whole fabbing the bracket thing can be sidestepped if you use a lokar throttle cable. I used one of their adjustable cables and jsut junked the lokar cable housing that came with it and used the stock throttle cable housing. Hooked it all up and it worked perfectly.

 

Just so yall know, AJ92RS350 has this exact same motor with a Turbo City TB on it, and it has put out a dynoed proven 319 HP and 399 lb/ft. Since Turbo City's website it down, I don't know what kind of injectors he's running. He did say that if he could have done it again, he would have gone with the Holley, but I'm all about not having to fabricate anything. Plus, I'm not that good at fabricating.

Loker throttle cable??? So what you're saying is, that I wouldn't have to fabricate the holley brakcet at all and I could just use this cable for my cruise control? I'm a little confused on this one.

 

Opps... didnt read far enough down in the first post.

Lokar stuff took care of the throttle and such but I dont have cruise control anymore. An easy aproach which worked like a charm for my origional throttle cable after i broke the cable (long story) was just to splice a section of cableing in. Or, you can get a a defunct cruise control unit from a yard and cut the cable with linkage attached to get the needed extra cable to reach the tbi and then splice that in with a cable crimp. Its clean and its easier then welding a bracket up. I dont know where to get the crimps from since I scavanged mine but im sure theyre available. The linkage on the end of the cable can also be spread apart and removed if your careful but i dont know if the cruise control unit can be disasembled and the cable replaced with another.

Doing the above should allow you to use the stock throttle bracket if your using an off center adapter. The easiest solution of all is not to use an off centerd adapter or an off centered intake so theres not as much work to be done.

 

Nope, just Gtec times that I know better then to share. I use my Gtec alot for chip tuning.

Making crap of my mods?? I dont think they are to shabby.
ported s/r torquers
ZZ4 cam
performer rpm manifold
65# injectors
hooker headers and full exhaust
cold air hood
actual chip tuning (not mail order)

 

Aw, c'mon, you can share them . Most people here know enough that gtec times are an estimate and not to be taken as absolute fact but non the less it does give an idea of how a setup is doing.

 

Well I'm thinking I might just reuse my stock throttle body and throw on those 65# injectors and TDS afpr and see how it does. If I feel it's choking the engine off, I'll just upgrade later. Of course I'll do the ultimate TBI to the throttle body so that will improve it a little.

OK, a couple of questions though. . .

Does anybody know what the gm parts number is for those 65# injectors is?

Do you think that 65#'s with about 15 psi will be enough or would the 85#'s at say 11 psi be better?

Do I need to updgrade my fuel pump? If so, any recommendations?

Thanks for yall's help.

 

I'm runnin 75 pph injectors at 21 psi and they are just barely feeding my 300-325 hp motor. I'm not completely tunes yet but I could need more pressure before it's over with. I hate to sound negative but I really think your going to need to look into chip burning with that much stuff being that far from stock. It will run but how well is anyone's guess. If your are set on running the caprice chip then I would pass on the holley tb and use the stock size caprice injectors so that there is that much less different from a stock 350.

As for the holley tb you can just swap out your stock throttle shaft for the holley shaft and have all your stock hookups. As long as the tb is in the same place on the intake as your stock one everything will hook up fine. As for the wires, they really aren't that bad to splice up.

 

Chip tuning is a necessity to get the most out of a motor. BMmonteSS, do I understand that you have tuned your PE in your chip and still feel you need more fuel than your getting delivered (with 75# injectors at 21 psi)? Or are you turning up the pressure on a stock type chip? 75# injectors at stock pressure should support 300HP. Are you sure that is lean? The reason I ask is that I got as much performence increase from correcting the timing tables as I did from correcting the WOT air fuel ratio.

 

If im not mistaken youll need to do a touch of minor machining to accomodate teh 2 in butteflies on the stock sb tbi throttle shaft. The slots are too narrow. Correct me if Im wrong, though.

 

So what you're saying is that I can just take the throttle bracket off of the stock throttle body and put it on the Holley?


And yeah, I know that I need to get into chip burning, but I'm holding off on purchasing that stuff until I get back home and actually see how the car is running.

 

Yes, i think the throttle shaft will physically fit in the holley unit but the 'slots' in the shaft will have to be enlarged so the butterflies can be mounted, unless its a shaft from a bb tbi unit.

 

gunny,

hope all is well in afghanistan.

couple of thoughts ....

a couple of weeks back, someone posted that he'd successfully bored his edelbrock tbi intake out to 2". he even posted pics. anyone remember?

while i don't think a 305 needs a bigger tb, i do believe a modded 350 will. affordable fuel injection regular sells holley 670 bases on ebay for 80 bucks with no injector towers. i believe you could use your stock tbi injector tower, a set of 65pph injectors and do pretty well.

also, you're making 180hp with no headers? that rocks. the best i can do so far is 170 with slp 1 3/4s! where did you get yours dynod? i go to dynolab.

make sure you keep your kevlar jockstrap on, dude.

 

Yeah it's cool. Nothing like having a rocket fly right over your hooch and miss you by 100 meters.


Yeah, I remember that post, but that guy took it to a special machine shop in order to do it. The only place I can't think of that would be able to do that back home is one of those shops near Dixie Speedway

I also got mined dynoed at the same place. I have no idea how I'm making that much with what little I've done to the motor itself as far as power issues go. Lucky I guess.

Yeah, our new bullet vest are awesome. Although that jewels protector does feel a little awkward to say the least.

 

Joker: My VE curve is in the ball park right now not completely tuned, + or - 5% or so. The injectors are going erratic at 6000 right now and I'm not completely sure if I'm lean or rich on the top end right now. I just figured out that the motot cutting out was the injectors going fubar and not some other problem with my swap. I'm running 21 psi witha BPW of about 90. Once I get some time to really get it tuned in I'll be able to tell you exactly what the motor needs. I may be making more power than 300 I'm turning 97 mph in the quarter in a 3650 pound car. That is just my best guestimate. Before I started tuning I was dead sure I wouldn't need more than 15 psi with the 75 pound injectors I had but man was I wrong.

By the way this is a mucho moddified chip It wouldn't even run with a stock 350 bin or even a 454 bin.

 

Maybe the BPW is the problem. A higher number would deliver more fuel per pulse right? Or did I lose my mind some where? If I remember correctly the cop car bin I used had the BPW set at 135 and I brought that down to 108 to bring the VE tables closer before adjusting the BLM's.( I was way rich at idle and cruise with my cam) . Also you say your VE tables are close, but what about your PE air fuel ratio? have you tuned it?
Its been awhile since I did any chip tuning, but I'll need to start over this spring. I got a 357 (.040" over) short block waiting for my heads and cam. I'm going to make a poor man's ZZ4 out of it. My plan is to use a small block TBI that I bored to 48MM to feed it. I know that may sound to small but it should flow arround 610 cfm if flow is anywhere near constant to bore size. (I compared bore size and flow on TBI's of known flow rates). 610 should flow enough for 6000rpm and my cam peaks at 5200 rpm on a real ZZ4. I'll probably try my 65# injectors at 23-25 lbs and see if that will work. I'm more concerned about high pressure forcing fuel to leak then damaging the injectors.
Well Good luck to every one doing injector mods.

 

I'm with you on the concern with leaks. I was running 65's at 30 PSI for while and it held up. I've also run it up to 60 PSI (engine not running) to test it and didn't have any leaking. My understanding it that GM runs these same TBI units at 30 PSI.

One thing that is important is to use the removable Loktite (blue) on the pod screws and torque them to spec (which I don't have with me at the moment).

RBob.

 

Yes increasing your bpw constant delivers more fuel but my problem was I was running out of pulse width. Basically I was trying to spray 8 milliseconds worth of fuel in 5 milliseconds. The car would litterally hit a wall when it would do this. With some help from Rbob and others I was able to get it figured out. Here's a link to my thread that has some really usefull info on how to get your timing and PW numbers to come out in winaldl.
https://www.thirdgen.org/techbb2/sho...hreadid=210908

I got this figured out about the time winter hit us up here so my car isn't 100% tuned yet. I would give it about 80-90%. My VE is pretty close at part throttle but my idle is still stinky because the cam I'm using is just confusing the O2 sensor at idle. I need to tune it by "nose". WOT tuning is next. I got in to the point where I can run it to 6000 rpm without it cutting out, or better described as running the injectors static. I just need to get ahold of a WB or get to the track to tune by mph and plug cuts.