Well I think the verdict is in, I was definately without question static with the 305 injectors, i might even hazard to guess they were static by 4500 rpm.

I went to the junkyard today and picked up an early model 454 TBI unit (they wouldnt just sell me the injectors) and got the old 454 injectors that had been claimed as 90 lbers (rbob says they are 80.5) I put those on, put my fp at 20 psi, dropped my bpw from 112 to 72 and off I went.

Basically, big injectors completely throw off your cal no matter what you do with bpw, I played around with FP to try and find a sweet spot but to no avail, some parts were real rich, some parts were lean.. I guess it just changes the proportions of things

I went from the car being rediculously lean at around 5000 rpm and worse as rpms came up to being able to pull clean to 6k and have it "rich enough" I actually have to pull back alot of fuel, its too rich! The monster is now being fed.


Once again I must tell you that the wideband is a must for tuning a setup like this. I have now seen the light, I wouldnt even bother trying to tune another car like this without a wideband.


BTW, anyone wanna buy a GM 454 throttle body from me sans injectors? I can throw in two sets of stock injectors if you wish... any idea on what this is worth?

 

i dont know what its worth. but im interested. it has injectors or no??

 

yeah, like i said ill throw in a set of stock injectors, i.e. stock 305 injectors

 

i was just reading on another thread how it made a guys car run really rich. will it do that to mine??im looking to get a spare tbi like yours to port the lip out of it and see who can make an adjustable regulator for it. i know you can and seen peoples bit dont know how to myself?? i have a 350 so i guess the 305 inj wont be any good for me. but name a price and throw them in

 

Nice, good to know its getting ample fuel up that high. That's a fairly stout little 305 too. You are running a 670 right? Is it pulling any vacuum at WOT up around 6000 or no? I forget what the cam you were using in there too, refresh my memory. Good to hear you got it running well; track times soon?

 

didnt make any vacuum datalogs or anything like that yet. The car still needs to be tuned in to run hard enough to pull alot of air, its on the rich side so that would skew any results of a test like that.

I dont think Im going to have any vacuum whatsoever though, with the 600cfm carb I was not pulling any vacuum worth mentioning even shifting at 6k (maybe about 2 kpa, ill have to look at the logs again)

 

I too have the 454 injectors, but on my 350. Mine are red and blue I believe. . . are yours the same?? I've been using 85#'s as my variable when planning.

If you read my other thread about the swap, you'll see that I was way high as well (eg 25 psi), and had to go to a stock 305 spring in order to turn her down. (Thanks to Sean for that by the way).:hail:

Anyways, I haven't datalogged since the swap, so I don't know what my tables look like yet. It might even be similiar even though I'm sitting on 45 more cubes. I really think 65#'s would have been the way to go, except they cost twice as much as the rest of them.

 

I purposely raised my FP so that I could set a real low BPW. I wanted to make the tables so that I couldnt make my injectors static even if I wanted to.

Right now i have WOT almost tuned in and im sitting at a bpw of 68 with my VE coming out to around 88% at 5200 rpm where it seems to be peaking out (still a little rough)


the one thing about setting BPW that low and pressure that high is it throws off your pump shot and i think it may be screwing with some deceleration enleanment parameters.

But yeah I have the darkblue/dark red injectors which were previously known as 90s but apparently are actually 80.5's.
I too thoughtthat the smaller injectors could hack it and finally with the WBo2 I found that there was no way, even at 40+ psi the stock 305 injectors werent cutting it. I think you are muchbetter off for the long run with the bigger injectors. As you can see, im even pushing these a little far and thats only on a 305. The good thing is the pressure can always be raised even more.

On a related note, now that i have the WOT roughed out (pretty consistent upper 12s AFR all the way to 6) ive notice that the exhaust note has become downright savage! I dont know why, i can make guesses but i can tell you for certain the low end and midrange have improved over the carburetor dramatically, throttle response is not even comparable. My butt dyno is not calibrated enough to tell any difference top end though.

It just occurred to me that i might be able to tell a difference using my datalogs and the timestamp.. i might do that.