After engine mods should the values in the VE table be lower or higher? I'm only looking for generalisation here.. I know absolute values can vary depending on specific mods done. But, I noticed that my entire VE table is lower than the stock table and I'm wondering if that might be the source of some of my tuning issues. Thanks for any input on the topic.
If your mods increased engine airflow efficiency above stock, the numbers will be higher, if not, they'll be lower. A high-lift cam, for example, will reduce stock VE values below 2000 rpm due to value overlap, and increase them above 3600 rpm where the cam and heads flow better. If you're tuning this yourself, tune the MAF first. You'll see an immediate and noticeable difference.
__________________
Best regards,
Bill
Calgary, Alberta, Canada
2003 Quicksilver roadster , 1SB, F55, QF5, MN6, Z06 Ti catback, 2 cat H-pipe & air lid, Euro red/amber tails, Vette Net, and HP Tuners s/w - available for free to anyone in Calgary
Thanks, that's the kind of info I was looking for. The car has a large cam and FAST intake, ported TB etc. I assumed the #'s should be higher than stock at some point yet my whole table is lower than stock. I have played with tuning to a small extent but, I don't think I'm ready to start tuning the whole thing myself without extensive help and guidance.
What types of symptoms are you having that lead you to change the tune? Have you logged data indicating that there needs to be a change - with a wideband or a good drive logging the LTFT's/STFT's? If you would like, send your tune file to me at fieroslave@yahoo.com and I will give it a look.
I live right up the road in Cape Canaveral and have some experience with HP tuners - if you would ever like some help just shoot me a pm and maybe we can meet up sometime. Good luck,
If your mods increased engine airflow efficiency above stock, the numbers will be higher, if not, they'll be lower. A high-lift cam, for example, will reduce stock VE values below 2000 rpm due to value overlap, and increase them above 3600 rpm where the cam and heads flow better. If you're tuning this yourself, tune the MAF first. You'll see an immediate and noticeable difference.
Do you have a good write up on how to tune the MAF? I'm using EFI Live.
I use HPTuners, but for EFILive, set B0120 to 200 to configure the tune for all-maf. Set B3801 to disable, so you can use the STFTs to tune the closed loop portion of the maf table. Reset the fuel trims. Set your PE table to reflect the afr you want at WOT. Hook up your wideband and use it to tune the WOT portion of the maf table. You can tune both from the same log - about five logs/corrections and you should be very close to perfect.
For an ideal tune, find some hilly roads, pick a gear that lets the car run at 1600-2000 rpm, set the cruise control and let the car cruise up and down the hills to populate the maf table cells. Then make three back to back runs in the same log to WOT. That should give you lots of valid data to correct the maf table.
__________________
Best regards,
Bill
Calgary, Alberta, Canada
2003 Quicksilver roadster , 1SB, F55, QF5, MN6, Z06 Ti catback, 2 cat H-pipe & air lid, Euro red/amber tails, Vette Net, and HP Tuners s/w - available for free to anyone in Calgary
Last edited by Billf6531; 10-11-2009 at 05:55 PM.
Reason: added more methodology
Hi, maybe you can help me. I installed a Vararam to weeks ago and since then I got a PO171 lean left bank one when I first was running it in the garage. I cleared the code and drove it and the next day getting on the freeway same code came back. Cleared it again and drove for a week and its not running right. It idles rough and I can smell that rotting egg smell when I pull in the garage. I have done the idle relearn thing. I also disconnected the battery for 30 minutes as recommended by forum members. I have driven it about 100 miles and last night I was pulling out of a parking lot and got the code PO174 lean right bank.
I have access to tunning software, JET DST. Also I put a 160 thermostat
and reset the fans on at 187 off at 182. It runs 180 on the freeway.
Any ideas?
Thanks for any help you might have.
The first thing I'd do is check for an air leak at all the connections between the Vararam and the throttle body. Second, log the trims. A colder thermostat will require more fuel.
Is there a specific reason you put in a colder thermostat? These LSx engines like heat, and run well with stock thermostats and appropriately adjusted fans. When you think about it, your new thermostat opens at about 160*, and then the engine has to heat up all the coolant in the rad to reach it's 180* operating temperature. If you must change the stock thermostat, why not put in a 180*?
__________________
Best regards,
Bill
Calgary, Alberta, Canada
2003 Quicksilver roadster , 1SB, F55, QF5, MN6, Z06 Ti catback, 2 cat H-pipe & air lid, Euro red/amber tails, Vette Net, and HP Tuners s/w - available for free to anyone in Calgary
The first thing I'd do is check for an air leak at all the connections between the Vararam and the throttle body. Second, log the trims. A colder thermostat will require more fuel.
Is there a specific reason you put in a colder thermostat? These LSx engines like heat, and run well with stock thermostats and appropriately adjusted fans. When you think about it, your new thermostat opens at about 160*, and then the engine has to heat up all the coolant in the rad to reach it's 180* operating temperature. If you must change the stock thermostat, why not put in a 180*?
Thanks for the quick response
I put the 160 because some of the guys here on the forum recommended it for better performance. I have checked for leaks and found none. What therm do you use?
BTW, I have a 02 Z06 if that makes any difference.
180*. - NO, not 180* - mine is the stock 190* thermostat.
__________________
Best regards,
Bill
Calgary, Alberta, Canada
2003 Quicksilver roadster , 1SB, F55, QF5, MN6, Z06 Ti catback, 2 cat H-pipe & air lid, Euro red/amber tails, Vette Net, and HP Tuners s/w - available for free to anyone in Calgary
Last edited by Billf6531; 10-11-2009 at 08:38 PM.
Reason: brain fart
I would. I've maf-tuned a number of C5s and Zs with Vararam air and never had a problem with the stock Mafs, screened or not.
__________________
Best regards,
Bill
Calgary, Alberta, Canada
2003 Quicksilver roadster , 1SB, F55, QF5, MN6, Z06 Ti catback, 2 cat H-pipe & air lid, Euro red/amber tails, Vette Net, and HP Tuners s/w - available for free to anyone in Calgary
It depends on what your fuel trims are now. Take a short log up to 4500 rpm and determine an average. If you're adding 10% fuel, multiply your maf table by 1.1, and after you've adjusted your PE table to reflect the WOT afr that you want, and connected your wideband, just tune your maf table from there using the narrow band sensors for closed loop and the w/b for wot open loop. About five 30 minute logs after the oil temperature is 85* should get you very close.
__________________
Best regards,
Bill
Calgary, Alberta, Canada
2003 Quicksilver roadster , 1SB, F55, QF5, MN6, Z06 Ti catback, 2 cat H-pipe & air lid, Euro red/amber tails, Vette Net, and HP Tuners s/w - available for free to anyone in Calgary
Do you have a good write up on how to tune the MAF? I'm using EFI Live.
EFILive forums are great for help.
That said
B0120 to 400 (Default is 4000, I set it to 1000, but tutorials say 400)
Usually your MAF kicks in at 4000 and your car runs off the VE table till then. By making this change, you will be running off your MAF instead of the table. I use 1000 to not mess with the idle range.
B3801 Disable (this turns of the LT Fuel Trims)
(Note that you can also tune based on the Fuel trims, but you will need some custom PID's to be able to map the Avg LTFT Ben's. Search the EFILive forums if you are that serious)
B3313 change from 86f to 252f, this basically turns off the Decel Fuel Cut off feature
Setup you maps in the SCAN Tool to get you the B5001 MAFFreq vs. your Wideband. Use the default filter from the tutorials, count of 50 may not hit all cells, try a lower value. Copy with labels from the map, then switch to the tune tool and paste and multiply into B5001. Repeat until the values are +-.98% correct.
B0120 to 400 (Default is 4000, I set it to 1000, but tutorials say 400)
Usually your MAF kicks in at 4000 and your car runs off the VE table till then. By making this change, you will be running off your MAF instead of the table. I use 1000 to not mess with the idle range.
B3801 Disable (this turns of the LT Fuel Trims)
(Note that you can also tune based on the Fuel trims, but you will need some custom PID's to be able to map the Avg LTFT Ben's. Search the EFILive forums if you are that serious)
B3313 change from 86f to 252f, this basically turns off the Decel Fuel Cut off feature
Setup you maps in the SCAN Tool to get you the B5001 MAFFreq vs. your Wideband. Use the default filter from the tutorials, count of 50 may not hit all cells, try a lower value. Copy with labels from the map, then switch to the tune tool and paste and multiply into B5001. Repeat until the values are +-.98% correct.
Always watch your engine knock retard pid.
Thanks, I may go at this myself. I just need to get the wb hooked up and tested.
Corvette Store
VE table ?
I have played with tuning to a small extent but, I don't think I'm ready to start tuning the whole thing myself without extensive help and guidance.
