Need master tuners help!
Thread Starter
Advanced
Joined: Apr 2003
Posts: 55
Likes: 0
From: Statesville NC
Need master tuners help!
I have added a superchager to my 92 ls1. I only runnning about 6lbs of boost. I reprogrammed the Eprom to run on a daily driving. I've changed the timing and eff. mixture, BUT now need to change MAP sensor from 1 bar to 2 bar. I using Datamaster to scan and CATS tuner to program the Eprom. I need to know all that I need to change to make sure I don't miss something. If someone could point me were to start or have a bin file that would show me a basic 2 bar change, so I could start from there. I know it would be better or wiser to have it done, but I don't learn anything that way, and I would rather learn so I could do it again than pay to never learn. So any help that some one could give would be GREATLY needed and helpful!
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
akhdnh,
You do not want ot change the MAP on your engine to a 2 bar... You would want to add an additional 2 bar if you are planning on adding suplimentary things such as feul pump modulation system or like water injection...
The best thing to do is to monitor your spark knock andyour O2 sensors, besure you are not leaning out at the upper end and you may need to trim back your timing at 90-100 KPA you should be able to see this from your logging program.
if you need more help feel free to email me...
Mo
You do not want ot change the MAP on your engine to a 2 bar... You would want to add an additional 2 bar if you are planning on adding suplimentary things such as feul pump modulation system or like water injection...
The best thing to do is to monitor your spark knock andyour O2 sensors, besure you are not leaning out at the upper end and you may need to trim back your timing at 90-100 KPA you should be able to see this from your logging program.
if you need more help feel free to email me...
Mo
Thread Starter
Advanced
Joined: Apr 2003
Posts: 55
Likes: 0
From: Statesville NC
???????
I have looked though many of scans, and it seems to be the biggest problem when the boost kicks in. I have moved the timing already and the o2 readings seem to be fine (it stays in range fine), but it knocks when the boost kicks in and the map reading go off the scale. I MAP sensor is not reading any boost just vacuum. So I need to change the sensor to one that will read boost (Right?). So mentioned just adding one. How do I add one? Don't I replace the old one?
Instructor
Joined: Jun 2003
Posts: 100
Likes: 0
From: broken arrow ok
akhdnh, I dont know if your understanding how the 2 bar map sensor works. It doesnt really read boost differently than vacum. Let me try to explain it, and somebody please correct me if i'm wrong. The map sensor works with voltage. example, lets say idle is 1 volt and wot is 5 volts. once the vacum is at zero( or 5 volts) the map is telling the computer that your at wot which with a supercharger can be achieved at less than full throttle. So you have no room to add more fuel. With a two bar map sensor is cuts the graph in half. example. now idle is 1 volt, zero vacum is 2.5 volts, 5 volts is 14.5 psi of boost. Now look at what the computer would think if you put in the 2 bar with no map table change. when your at zero vacum it's only going to give part throttle fuel and your going to be way lean. You will have to change the whole map table and cut in half and redo it along with the other tables that read ve%. Does this sound right everybody
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
new '92
Yes you are correct. That is why most people will not go through all of that trouble. I like others just have 2 bars attached to the manifold and when the boost reaches 100Kpa the ancilary control systems for boost or alcohol ijection then switch on...
Not saying it cannot be done but it would require a lot of work in my opinion
akhdnh
i'll resend my email to you...
Mo
Yes you are correct. That is why most people will not go through all of that trouble. I like others just have 2 bars attached to the manifold and when the boost reaches 100Kpa the ancilary control systems for boost or alcohol ijection then switch on...
Not saying it cannot be done but it would require a lot of work in my opinion
akhdnh
i'll resend my email to you...
Mo
Thread Starter
Advanced
Joined: Apr 2003
Posts: 55
Likes: 0
From: Statesville NC
thanks again guys
As I think I mentioned, when the throttle is is first open or opened rapidly the map pegs! At that point it knock, then the knock retard jumps in and it still knock until you get out of it or until in catches up and the map drops. It doesn't stay there long, but long enough everytime you get into the throttle. And even though I knew better I got into it one too many times before and had to rebuild the engine. I cracked 5 pistons. I'm hoping to get get something resolved before I do it again. So I was thinking of moving the timing even more and changing the knock retard some so I can dance around it. This I believe will work but it still doesn't real see or do anything with the boost. I know that changing everything is a lot of work but the way my car is working and responding to the boost I think it might be the best way.
As for the part about you saying you just added a 2 bar for ancilary control systems to help. I don't know that I have heard of this or know were to start. So could you tell me a little or a lot more so I can see if that will be an option for me.
As for the part about you saying you just added a 2 bar for ancilary control systems to help. I don't know that I have heard of this or know were to start. So could you tell me a little or a lot more so I can see if that will be an option for me.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
akhdnh,
Have you tried pulling off the belt on the supercharger ansd see what happens? Or disconnect the "snorkel "to the throttle body just to try the normal aspriation, It would also tell you what spark knock is happening...
If you go to www.carrollsupercharging.com look at the superpumper II they have information about runing a 2 bar system along with your 1 bar. Basically as i think i've said before... once you hit boost this turns on a axilary fuel pump and a soliniod that blocks threturn path to the fuel tank boosting your fuel pressure... it has like 10 settings at each 500 rpm increments that allows you to dial in the appropriate fuel pressure for each one... it reall y sounds to me like you are running lean I have had situatons where the fuel enrichement was too lean and even driving around I was getting 9 degrees of knock retard in CLOSED loop. your timing shouldnt be more than say 25 or 26 degrees at 5500 RPM.
If you can log a run and send it to me I can help you further... Otherwise I'm shooting in the dark...
mo
Have you tried pulling off the belt on the supercharger ansd see what happens? Or disconnect the "snorkel "to the throttle body just to try the normal aspriation, It would also tell you what spark knock is happening...
If you go to www.carrollsupercharging.com look at the superpumper II they have information about runing a 2 bar system along with your 1 bar. Basically as i think i've said before... once you hit boost this turns on a axilary fuel pump and a soliniod that blocks threturn path to the fuel tank boosting your fuel pressure... it has like 10 settings at each 500 rpm increments that allows you to dial in the appropriate fuel pressure for each one... it reall y sounds to me like you are running lean I have had situatons where the fuel enrichement was too lean and even driving around I was getting 9 degrees of knock retard in CLOSED loop. your timing shouldnt be more than say 25 or 26 degrees at 5500 RPM.
If you can log a run and send it to me I can help you further... Otherwise I'm shooting in the dark...
mo
Thread Starter
Advanced
Joined: Apr 2003
Posts: 55
Likes: 0
From: Statesville NC
I've been using datamaster to scan my runs. Can you use that? Also I haven't got a recent one since I rebuilt the motor, so I 'll try to get a recent scan for you. But about the leaning out the S term count does lean out (so I need t oadjust that some omre) but I don't think it is lean enough to be causing the problem.
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
Look at your O2's at WOT or as high as you feel safe going above ~ 60 % throttle... you should be a minimum of 900's with out an intercooler i was having to push to about 930 to stop the knock...
If you can export your datamaster file to a CVS ( comma deliniated file) most do... I can read it from there...
Mo
If you can export your datamaster file to a CVS ( comma deliniated file) most do... I can read it from there...
Mo