Tbi-MAX

woot woot, its completed on the lift! now, Oldred just threw a good idea into my head! which Alvin was trying to tell me all along. But Oldred said for me to put back in the stock 61# injectors and run them at a very high psi, to feed my combo, and the spray pattern will be even finer of a mist, to help the TBI atomize the mixture better. leading into better mpg as well... i thought this was just great. now instead of the other regulator i was planing, i am just going to order a import unit so i can regulate my psi anywhere over 20psi! and get a really misty spray... so once i start logging and tuning, i can work even better on my mpg tune. its just like the BBC injectors dont spray very finely. so im going to re-install the SBC injectors, into the BBC throttle body, order a import regulator, and go from there with the tuning... now can someone calculate how much psi will it take to feed 350 or so hp and say 450# of tq with 61# stock suv injectors? also why is it not discussed or said, its better to run smaller injectors at a higher psi?

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Ronny

http://www.users.bigpond.net.au/ben_...ctorsizing.xls

Tbi-MAX

ok so i played with that, and entered 61 rated at 13psi with injector duty cycle at 90% BSCF 0.45 with a new pressure of 28 psi will feed 358hp!

does all of this sound correct? im going to take the spring out the BBC regulator, install the 61#s and get the after market import ***** regulator.

Ronny

Watch your duty cycle. I think my duty cycle in AE was higher than PE. My point is that you may need more fuel than you think and you may end up going back to the big inj's.

Tbi-MAX

what should the duty cycle be set at then? in the excel document? if i need more fuel, cant i just turn the psi up? the import regulators reg from 20psi all the way up to 50psi... i think oldred is running near 40 psi on his 350ci. and he has set his reg up to 50 psi b4 i read. so will i still need the BBC injectors?

Tbi-MAX

alright got the VAFPR ordered, it will be here this week. Im going to use the SBC injectors after talking with Oldred, 91chev and the other guys on FSC. Also I didnt realize Fast305 was using 46# injectors on his 500hp beast he built a few mnths back, at like 60 psi...

here is the VAFPR i will be runing the 61# with:

Ronny

Try the smaller injectors. Just watch the duty cycle. DC should be under 90% if I recall. It is not a setting in bin. It is a reading in your datalog (TP-RT). 100% means you are a max capacity of the inj. If so you increase FP or go larger inj. Thought TBI injectors can be run as high as 30 lbs? Maybe Fast355 ran them higher. Not sure.

Tbi-MAX

man you have been helpful & it clears stuff up for me. makes sense about dataloging to see the DC! sweet.. yea, i was doing some major intesive searching last night. NO you are incorecct with 30psi, the stock marine VAFPR those run up to 30psi..

As long as you have the pump to supply it, and external reg.. it does whatever the pump is willing to give.. the regulator i got say 20-140 psi on the gauge..

Rbob has tested the injectors up to 60psi himself.. and the sprayed perfectly fine he said.. and alot of people are runing both SBC & BBC injectors at those psis daily ranging from 40-50psi.. but the 61# is the injec of choice. same injectors ill be using, that came stock with my truck.

Oldred runs about 50psi WOT and 30psi @ idle...

i got the 61# injectors installed back in the truck today.. surpiseingly the truck cranks up quicker than ever with just the key! no more foot is needed at all... at the same psi as the BBC i managed to get a small lean pop around 15-1600rpm, so i shut it down.. took the reg off, and turned that up to MAX psi possible on the stock reg and BBC spring. So now the stock tbi regulator is MAXED out with the walbaro 255 in the tank... the lean pop was gone! but i notice i had to open the TB blades slow as the air gush is too much without the tune. so it will still lean pop, but no where as easily... i would guestimate its around 16-17psi.. (too little)

no more black water is coming out the exhaust and it doesnt smell rich anymore. but when i get the VAFPR installed, i will set it to the calculated psi... and start to tune from there.. i cant wait.. its been way over due. and all of this is starting to make perfect sense to me.

i entered DC as 88% BSFC as 0.45 with a calculated pressure of 29psi. I should support 356hp!

so when i get the stuff in, and bypass the stock regulator by removing the spring, and putting it back together.. cutting the return line, and installing the VAFPR in series. I will set it @ 29psi to start with..

Tbi-MAX

setting the psi tomorrow, after i finish connecting the return lines..



tuning phase has begun..

Tbi-MAX

wow, it doesnt look like that above anymore..



tuning is 100% better than the dyno tune. truck runs so much more better its not even funny!

BronYrAur

looks great, sounds good, glad the tuning is working out for ya! I can't help but notice you zoomed in on an open vacuum port on the TBI though, that's a vacuum leak and should be blocked off.

Tbi-MAX

had to bump for updates...

well it sounds even better now, and im getting the tune under proper order. yea, i knew about the vac leak.

here i go acting a fool, but you can hear the engine, i just wanted video of how healthy the motor sounds.

comp

thanks for update

JohnBlazeLTZ

How's she running Max?

BackInBlack86

406 in the works, pretty sure he told me he sold the 383

__________________
"There's Something About A Woman In Flame Retardant Pants..."

JohnBlazeLTZ

Really? Wow...I am surprised by that...come on Max...we need an update I guess! Why you trying to surprise us with a 406? ~

Fast355

Thats my next engine as well, a healthy 406 to replace my current 350.

__________________
350 Vortec shortblock, balanced, blueprinted, 18cc dished pistons, total seal rings, ported 906 Vortecs, Edelbrock TPI Vortec base, Custom Reed Grind Hydraulic Roller Cam, Doug Thorley Tri-Ys, 2 1/2" exhaust, Stock TPI runners and plenum, stock 48mm TB, 24# LT1 injectors, AFPR @ 46 psi, 7730 ECM, DIY Tuning, stock 1,600 rpm stalled 700r4, 3.08 gears, P295/50/R17 tires.

Soon- 4L60E and 7427 TBI PCM in MPFI mode

RFmaster

Hey Fast

Which heads are you planing for your 406??? Vortec or something a bit bigger (and meaner)???? This is a good thread as I'm basically about to repeat 383TBI build (vortec heads and K1012 or 1013 cam equivalent).

//RF

Tbi-MAX

ok, hey guys... its been along time.. yes... the cat is out bag. i thought this was on hushhh... Johnny sorry for the late response.. ok here is the low down. You guys know I did this on a budget under 2700... turned around sold it for 4200. and building my 408 SBC.. yes small block!

JE forged pistons
6" NASCAR rods (out the back door)
double roller bottom end
HYDRALLIC roller lifters RETRO FIT
LUNATI "marine" cam... EXPECT 500HP & 520# tq b4 4000 rpms
AIR FLOW RESEARCH HEADS 190! 72 i belive
1.6 roller rockers... (i cant remember but my lift is like .57/.58 in that range) ill fix this later

compression is about 10.1 I plan on runing 93 as always.

its just going to be a TQ MONSTER... the burb should more like a bat out of hell with this new tq numbers.

again, Im going to TUNED PORT INJECTION.... ditched the TBI for about 500$ installed. got TPI for under 300$ loaded... budget is doing good... so far I have under 2000$ into all of this... as Ive gotten quality used parts, and brand new essential parts. Used parts are: RODS, LIFTERS, HEADS, PISTONS. they have been to the machine shop and checked and polished NEW! everything else is NEW from summit.

Im going to post some videos of the OLD 383 in a few momments.. then you guys can HEAR and get a GRASP of how it ran.

Tbi-MAX

okay here is 1 of my favs


ok heres another... still this was not nailed yet on the tune. part throttle


listen to her GROWL


people seem to like this one... (excuse the abs light is on) lol


1st startup after intake swap single plane HIGH rise.. BBC TBI.. 90# injs, yes i know its has a vaccum leak on the TBI nipple..

Tbi-MAX

here is the rubber i burn now...


little lesson on turning radius... my burb can bust a Uwee quick lets say... that modd was fun


she is getting painted ALL black and limo tint by summer..


would u think a 383 or wait.. 408?

Tbi-MAX

specs?

1hotroc

Hey Brent your ride looks like a lot of fun! Enjoy the torque of that tpi, talk to ya 1hotroc (Mike).

rocko350

Don't forget to put the rest of the lug nuts on. Why stop at a 406 when they can be stroked to a 434? A balanced, forged rotating assembly from www.competitionproducts.com can get you there fairly priced.

Chris

Tbi-MAX

thanks Mike!

hey Chris, those pics where just after i put the tires on... the truck looks alot different actually, you would be surprised. but its getting a new color shortly. I just had these parts for a steal. i had the exact same set of slightly used JE forged pistons for the 408 block i had purchased. I just couldnt turn down the price on them. basically a give away. so that way I saved like 800$ just on some "custom 434" pistons with the short skirts. As well as kicking 550+$ on the 4" crank. I simply went with a summit scat for 250$ so I wouldnt have to custom the pistons. Trust me I was itching to do it so bad. but things came up, moved, and had to put cash elsewhere.

however I have plans to SC this very same 408 in the future couple of months. while runing a TPI intake on it, It should put the TQ numbers about 650-700 ish Im hoping.


on the 383, I think the best mods, I actually could feel were, the: BBC TBI! the 90# injs were a charm as well, I really felt the long tube headers. I plan on doing a electric fan swap on the new engine as well. every little for mpg. but with more tq than my last engine, it really saves mpg, barely having to hit the gas pedal and all. 20% throttle, keeps you hanging with traffic.