Initial Startup
Thread Starter
Junior Member
Joined: Feb 2006
Posts: 58
Likes: 0
From: Winnipeg, MB, Canada
Car: 1991 K1500
Engine: 355 Vortec
Transmission: 700r4
Axle/Gears: 10 bolt, 3.42
Initial Startup
Folks:
I apologize in advance if this is kicking a dead horse... if so, please point me in the right direction, but my searches didn't reveal what I was looking for.
Been doing a significant amount of research into tuning... and on one hand think I've got a pretty decent grasp of at least performing basic tuning... however, on the flip side... I'm utterly confused. (Contradiction I know). Here's the scoop, and a couple of very brief questions:
My engine threw a rod bearing, so had it rebuilt (350 LO5 TBI originally from a roadmaster but going into a 4x4 chevy/1227747 ECM) with re-sized rods/bearings, ported 193's (Don't laugh... done alot of reading on that too and just didn't have the funds to go with different heads, but figured I could get some gains none the less), and a comp 262H-R12 computer roller cam (210/220 @0.050, .480/.480 lift). Also have flowtech shorty headers with aftermarket exhaust and have ported the TBI.
Now for the questions:
1) Is it better to go with 65lb/hr injectors and modify fuel pressure to around 19lbs? Or go with 80lb/hr injectors and keep FP lower? I've read mixed comments, but the one that stands to reason in my mind is that the fuel would be atomized better at higher psi... so the 65lb/hr would be better???
2) No matter the outcome from q 1, in order to have a driveable vehicle, can I simply modify the BPW to match injectors and then take my time (i.e. couple of weeks of spare time) to tune... or am I going to have problems and need to tune right off the start?
3) If the answer to q2 is that I will need to custom tune right from the start, are desktop dyno numbers (In terms of VE and MAP) good enough for a starting point? Or is there a program from another ECM that I could use that would work well as a starting point?
Thanks in advance for any help!!
I apologize in advance if this is kicking a dead horse... if so, please point me in the right direction, but my searches didn't reveal what I was looking for.
Been doing a significant amount of research into tuning... and on one hand think I've got a pretty decent grasp of at least performing basic tuning... however, on the flip side... I'm utterly confused. (Contradiction I know). Here's the scoop, and a couple of very brief questions:
My engine threw a rod bearing, so had it rebuilt (350 LO5 TBI originally from a roadmaster but going into a 4x4 chevy/1227747 ECM) with re-sized rods/bearings, ported 193's (Don't laugh... done alot of reading on that too and just didn't have the funds to go with different heads, but figured I could get some gains none the less), and a comp 262H-R12 computer roller cam (210/220 @0.050, .480/.480 lift). Also have flowtech shorty headers with aftermarket exhaust and have ported the TBI.
Now for the questions:
1) Is it better to go with 65lb/hr injectors and modify fuel pressure to around 19lbs? Or go with 80lb/hr injectors and keep FP lower? I've read mixed comments, but the one that stands to reason in my mind is that the fuel would be atomized better at higher psi... so the 65lb/hr would be better???
2) No matter the outcome from q 1, in order to have a driveable vehicle, can I simply modify the BPW to match injectors and then take my time (i.e. couple of weeks of spare time) to tune... or am I going to have problems and need to tune right off the start?
3) If the answer to q2 is that I will need to custom tune right from the start, are desktop dyno numbers (In terms of VE and MAP) good enough for a starting point? Or is there a program from another ECM that I could use that would work well as a starting point?
Thanks in advance for any help!!
Joined: Mar 2000
Posts: 1,692
Likes: 1
From: Corona
Car: 92 Form, 91 Z28, 89 GTA, 86 Z28
Engine: BP383 vortech, BP383, 5.7 TPI, LG4
Transmission: 4L60e, 700R4, 700R4..
Axle/Gears: 3.27, 2.73
I'd go with the 80's and an adjustable FPR. Gives you more playing room.
The BPC should get you running well enough on that setup. The cam is reasonably small (smaller than some "computer compatible" cams). Once the engine is warmed up, it should drive pretty well. I'd probably start off with some part load driving and adjusting the BPC to get 120's for BLM (a touch on the safe side at least).
The BPC should get you running well enough on that setup. The cam is reasonably small (smaller than some "computer compatible" cams). Once the engine is warmed up, it should drive pretty well. I'd probably start off with some part load driving and adjusting the BPC to get 120's for BLM (a touch on the safe side at least).
Thread
Thread Starter
Forum
Replies
Last Post
tyeo098
Tech / General Engine
38
Nov 30, 2015 06:27 PM