Help me brake in my 383 cam...........

[kayjef]

So I am new to the site, but have been reading here for a long time. I am a novice when it comes to tuning, but want to try and do it myself.

Truck 88 GMC Jimmy (fullsize)
Motor: 383 stroker (10:1)
Cam: SUM-1105 flat tappet cam. (summitracing)
Aluminum 190cc heads (64cc chamber)
Stock 454 Throttle body (80lb injectors)

My ecm right now is a 7747 and has a stock 350 tune.

I don't want to ruin my new cam by having a tune that won't start up and run good enough to break the cam in right away. I don't need it to run perfect, just good enough at first, and then I can fine tune if from there. I am assuming my current stock 350 tune isn't up to the task, but I wonder if I could do a stock 7.4L tbi tune to break the cam in? I know one guy who successfully did this, but it was with a 350 with a cam. I would assume it would work better with the added displacement of the 383.

I am thinking the easiest thing to do is snag someone's bin for a moderately built 383 who used big block injectors and go from there.
Any help is appreciated.

[dave w]

If you can you burn your own chip, the attached screen shot is the BPW for a '7747 / 383 / 80 lb. injectors.

dave w

[RobertISaar]

a neat trick may be to temporarily setup the commanded idle speed tables to the 2000 or so RPM you'll be spinning the engine at for the break-in procedure.

[kayjef]

Thanks for the quick reply.

Edit: My best guess is about 350hp with this motor. According to some calculations I have done it looks like that requires around 100lb/hr per injector. I have a fuel pressure regulator and it looks like I will need at least 18psi to get close to those numbers. So that means I will need to set a different BPW than that quoted 114 above right?

It probably isn't absolutely necessary to have it perfect to break the cam in, but my reading tells me having the BPW set as close to reality will make for easier tuning.

Thanks.

[dave w]

Very few of the engines I tune goes to the dyno. One of the TBI / Vortec 350 engines I tuned produced 330 RWHP, with a 16197427 PCM (RIP '7747), using 15 PSI fuel pressure and 5235231 (early 454 injectors).

I think a 16197427 PCM and Wide Band O2 Sensor (WBO2) would be almost mandatory for tuning your engine.

dave w

[Chewy1576]

I used a stock bin for a 350/5 speed as my baseline and modified the BPW for 80 lb/hr injectors and 18 psi FP. It was a good starting point.

[kayjef]

I used a stock bin for a 350/5 speed as my baseline and modified the BPW for 80 lb/hr injectors and 18 psi FP. It was a good starting point.

Hey Chewy, I read all your threads and although your cam is a little more mild than mine, everything else is rather similar. I downloaded your 'Blueprint 383 Chip v3.bin' (thanks for sharing ) and holy crap it is a lot different than than my stock bin (ASDU-$42-5.7L-Auto). The VE graph jumps around a lot whereas my stock one is substantially more smooth. Same goes for a lot of other tables. Is this one of the final tunes you did or were these substantially changed past where they are in this version?

If you can't tell I am a noob at tuning, but have been researching like a mother to try and not screw it up. Autoprom and a wideband 02 sensor is in the mail. So I should be operational here in a week and hopefully ready to fire this thing up a little after that.