I have been reading this forum for a year and it is the place to go for TBI info. I FINALY have my 383 project ready for the next stage TUNING. I have the 454 TBI unit with the 80lb injectors
ready to bolt on, but wanted to get the engine broke in before I started tuning. It now has the 5.7 TBI unit with 55lb injectors and a stock chip.
I have taken a data scan using Winaldl and would hope that one of the guru's could point me in the right direction to start the tuning project. I can email anyone that is interrested in looking at the file.

The engine has the following:
9.5 CR
383HT Roller Cam
.030 Keith Black Pistons 10cc inverted dish
6" rods
Performer Intake for Vortec Heads
Vortec Heads
Headers
Free flowing exhaust
Will have the 454 TBI Unit
80lb Injectors

I have the Autoprom and want to dive into this. But want to get a few pointers from the experts before I toast my $$$$$ engine.


Thanks for all the Info that has been made available to read, it has and is invaluable.

THANKS

 

Set the idle timing to like 20d, low load timing to no more then 35, and the higher K/Pa areas to like 20d.

Start your engine, and get it up to the 2K break in RPM. Watch to see that it goes closed loop, and that the BLs are within the limits, ie whatever the chip settings are.

Once past break-in, then work on getting a decent idle. Then look at the start up settings, and how it runs when cold. The cranking AFR, and choke AFRs can vary alot. Then, you can start on the low speed drivibility, via working on your BLs. Once you have the VE table worked out as much as you can, you can start invoking PE, and looking at the plugs.

A WB will shorten the process alot.
And, there no such thing as too much patience, or too much note taking.

 

Thanks 'Grumpy'
after reading about the EBL UTBI code that RBob is releasing soon I am going to wait for it before I start the tunning process. It should be worth the wait, it will give me more options and a shorter learning curve.

 

Just to give you an idea of what size injectors you want with TBI; take the lb/hr rating and divide by 4. That will give you the approximate injector size if you were running port injection (on a v8). Example; 61# injectors is like having a 15.25# TPI injectors . As you can see, not even GM felt that was enough for their 305's let alone 350's. The opposite works too, take 19# stock TPI injectors and mult by 4 you get the approx TBI injector size which is 76#, bbc injectors are right there and that's the largest TBI injector out there. As you can see, TBI is easily fuel limited and the only way to make the peak horsepower is to crank up the fuel pressure or add 2 more injectors with an add-on injector driver (expensive if bought).
To break it in, I'd run the stock TBI with stock injectors and increase the fuel pressure by 3-4psi with a stock chip and 4-8 degrees base timing. Have a scanner hooked up to monitor the closed loop operation. Break-in around 2000rpm, go up to about 2400 slowely watching the temps and oil pressure. Once up to 2400, go directly down slowely to around 1600 then back up to 2000 always moving the RPM slowely to get some different ignition timing. Watch the exhaust pipes. If they start to glow you're probably running either too rich or not enough timing, or both, so obviously try some timing but if it smells rich and the engine is running smooth it's a good bet you need to turn down the fuel . Good luck and don't worry about it. I broke in my engine with the TPS wired backwards and even drove around with it like that! Washed the cylinder walls with gas but caught it soon before any serious damage.

 

Thanks for all this info.
I think I am allright on basic operation of the engine at this point.
Engine Has about 300 miles on it now and really idles good and is very responsive in the sub 3000 RPM range. I have not yet opened it up above 3000 RPM.
Orderd a walbro 255 fuel pump and the adjusable regulator 0-40
I will hold off on putting the larger TBI and injectors on until I get the U-TBI and EBL.
Love the low end tourque of this 383
Just hope it doesn't eat gas like a big block with the large injectors and increased fuel pressure.
Thanks again!!!

 

Sorry Double click I guess

 

It's a common misconception is that larger injectors and more fuel pressure will be bad on gas. Change the calibration and you'll lower the pulse widths resulting in nearly if not exactly the same mileage!!
Definatly get a good strong fuel pump. TBI pumps are a joke. You'd be better off with a hand operated spray bottle pump.

 

Sure right about stock TBI pumps being lazy.
I adjusted the fuel pressure regulator and I could only get 13PSI out of the stock pump.

 

With the EBL, a 454, 3/4t P-U, utility bed, several hundred pounds of chains, pull downs, and towing gear I got 17.2 MPG last week. And, I'm hoping to beat that.

 

With the EBL, BIG ROLLER cammed 305 TBI (12 in/hg of vacuum at idle in P/N and 6 in/hg in Drive), 700r4, 2,800 stall, 3.73 gears pulling around 5,500 lbs, I averaged just shy of 18 MPG last tank(only about 150 highway miles and the rest city and heavy traffic, I see 5-10 MPG on instant calculations in traffic, 0 @ lights, 15-20 @ a steady 30-45 MPH and 20-25 @ 60-75 MPH on level sections of highway). The tune still is not quite right as I just swapped the cam a couple of weeks ago and haven't had time to fine tweak it. Lets just say ALPHA-N is Awesome!

I run 68 lb/hr injectors @ 32 PSI and can feed my engine to its 6,500 RPM redline.

The increased pressure and injector size, let me decrease the BPW and provide better air/fuel atomization. That seems to increase fuel mileage, clean up the emissions some, and decrease carbon buildup. All 8 plugs look like new!

TPI pump in the TBI Van tank.

Letting it shift @ 5,800 RPM in Drive, I ran a Sea Level Corrected 15.24 @ 96.7 MPH (312+5,500 lbs+ Aerodynamic Brick). Not giving any power up for the mileage I am gettign.

 

That is good to hear, I am really looking forward to tuning with the ebl any Ideas on how much longer before it is avalable?