This sounds very, very wrong. The spark curve should look roughly like the torque curve. 360 tq is within reason imo. The intake is going to show more loss at top end. Are you going to try taking over the tuning yourself?He said he set it at 19 degrees across the board.
Correct. Fairly quick advance rate up to about 24° by 2,400 through peak torque, then it should level off and slightly advance to maximum value of ~28-32° above peak HP. Correctly timed that cam should make peak torque around 3,500 and peak HP around 5K.Originally Posted by 1project2many
This is what I was using for 91+ octane fuel running a Vortec 350 with a GM LT1 F-car cam, 1.6 rockers, and long tube headers pulling around a 1999 Suburban with 3.73 gears and a GM 4.3 torque converter stalling around 2,800 rpm. I had 6K behind that Suburban more than once and it pulled a trailer on a hot day without knock retard. At the converter flash speed of 2,800 rpm at WOT I was already at 28* timing.
0-80 mph on an uphill on-ramp on a hot summer night.
https://www.youtube.com/watch?v=LYdyu501Z4Y
Last edited by Fast355; 05-09-2018 at 08:18 PM.
Fast,
Do you remember what the spark bias was for this timing table?
Yeah, I need to get this sorted out. I bought the Autoprom and AFR to do tune and datalogging. I am not sure if I should just start with the current chip and tune from there, or if I should scrap my $600 tune and start from someone else who has a similar setup? I was hoping someone had a similar setup that I could start from.
Either way I will modify from data.
Start from scratch, IMO. No telling what was modified or messed up. Start with my spark table, remove about 6* from the whole table until you can verify the fueling and knock retard. Then slowly bring in more timing as needed. Multiply your MAP and TPS AE by 1.5 as a starting point to fight lean pops and backfiring. Calculate your injector flow rate and put the value into the constant. Then tune your VEs. Once you get the engine running halfway decent you can play with your transmission shifting and torque converter. I would however set your trans line pressure to equal the Zero MPH line pressure values across the whole MPH table. Zero MPH line pressure is always higher on the TBIs than any other MPH.
Last edited by Fast355; 05-09-2018 at 08:27 PM.
I will do as you suggest.
Looking at the fuel injector calculator on WitchHunter's site, it would seem I need around 100 lb/hr of injector output. Do you feel this is about right?
Between all the hard parts I have sitting around, I can get to about any injector rate. The company that tuned my truck put in my 11 psi spring with one of my smaller injectors so they are probably around 62 lb/hr. I have another set that put out 75 lb/hr at 11 psi. I also have a few springs, 13 psi, 14, psi, 18 psi, and an adjustable regulator. The larger injectors with the 18 psi spring puts my rate near 96 lb/hr. I can use my adjustable base to bump up from there if needed.
Funny part is looking at the same calculator on WitchHunter's site given my current injector and pressure it suggests it should make near 230 hp crank. Really not too far off looking at the dyno sheet.
Posting Permissions
Reply With Quote
Bookmarks