98 TransAm LS1 Tuning Help
04-25-2014, 11:57 PM
#1
Staging Lane
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98 TransAm LS1 Tuning Help I'm looking for some help on tuning my 98 Trans Am LS1. I just installed BBK Long Tubes And BBK ORY-P but I left on the Stock I-pipe and muffler. I put a electric Bad Landz Cutout. I really enjoy have the stock muffler and having a nice quiet car when needed. Here's my issue...
I am having some issues tuning the VE tables my self. I compared my own tables ( HP Tuners) to a lot of other Stock Bin files and it looks like someone messed around with the tune before. The dyno I went to looked and said it looks like a hand held. I'm posting my dyno sheet. The AFR was a little lean for my liking. I like driving the car daily but it doesn't have to be my Daily. After looking through the VE and PE, I noticed during my latest data log I had a lot of knock. the Tuner at the Dyno said there was something on the sheet that looking like the timing was being pulled. If someone would mind taking a look at my tune file I would be grateful. Thanks The Tuner is HPtuners.
I am having some issues tuning the VE tables my self. I compared my own tables ( HP Tuners) to a lot of other Stock Bin files and it looks like someone messed around with the tune before. The dyno I went to looked and said it looks like a hand held. I'm posting my dyno sheet. The AFR was a little lean for my liking. I like driving the car daily but it doesn't have to be my Daily. After looking through the VE and PE, I noticed during my latest data log I had a lot of knock. the Tuner at the Dyno said there was something on the sheet that looking like the timing was being pulled. If someone would mind taking a look at my tune file I would be grateful. Thanks The Tuner is HPtuners.
04-26-2014, 10:24 AM
#2
98s have some very aggressive timing tables in them stock, they run more than I
run in a heads\cam car. The tune in your car is bone stock. VE and MAF should be
ok with just an exhaust upgrade. 13:1 is lean for a stock tune but is it really 13:1?
dynos typically use tail pipe clamp style O2s that are slow to respond and generally
error to the lean side. With that said though it running lean is a good recipe for knock
especially with the timing you have. A fuel pressure check would be a good start.
Check it KOEO and driving the car.
run in a heads\cam car. The tune in your car is bone stock. VE and MAF should be
ok with just an exhaust upgrade. 13:1 is lean for a stock tune but is it really 13:1?
dynos typically use tail pipe clamp style O2s that are slow to respond and generally
error to the lean side. With that said though it running lean is a good recipe for knock
especially with the timing you have. A fuel pressure check would be a good start.
Check it KOEO and driving the car.
04-26-2014, 04:31 PM
#3
Staging Lane
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98s have some very aggressive timing tables in them stock, they run more than I
run in a heads\cam car. The tune in your car is bone stock. VE and MAF should be
ok with just an exhaust upgrade. 13:1 is lean for a stock tune but is it really 13:1?
dynos typically use tail pipe clamp style O2s that are slow to respond and generally
error to the lean side. With that said though it running lean is a good recipe for knock
especially with the timing you have. A fuel pressure check would be a good start.
Check it KOEO and driving the car.
run in a heads\cam car. The tune in your car is bone stock. VE and MAF should be
ok with just an exhaust upgrade. 13:1 is lean for a stock tune but is it really 13:1?
dynos typically use tail pipe clamp style O2s that are slow to respond and generally
error to the lean side. With that said though it running lean is a good recipe for knock
especially with the timing you have. A fuel pressure check would be a good start.
Check it KOEO and driving the car.
Where would I got to add fuel? Do I need to data log the Trims again ? PE tables ?could you point me in a good direction ?
Thanks
04-26-2014, 05:23 PM
#4
Looking at the trims can be helpful plus or minus 7,8,9 is pretty common and fairly normal. At +15 you for sure have lean it will spit codes at +25
But trims do not tell the whole story you can have them fairly close and still run lean WOT. PCM will add positive trims to commanded PE which should be pretty rich if
the fuel system can deliver. Fuel pressure check @ KOEO and idle 58?
Put the gauge under the windshield wiper and do a WOT blast. Fuel pressure WOT
in the 40s could go that lean on a stock tune but your dyno numbers do not really reflect that.
But trims do not tell the whole story you can have them fairly close and still run lean WOT. PCM will add positive trims to commanded PE which should be pretty rich if
the fuel system can deliver. Fuel pressure check @ KOEO and idle 58?
Put the gauge under the windshield wiper and do a WOT blast. Fuel pressure WOT
in the 40s could go that lean on a stock tune but your dyno numbers do not really reflect that.
04-26-2014, 06:02 PM
#5
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VE table needs work and 28 degrees is more than most. You're commanding a 11.7 after 2k rpm and it was 13 on the dyno? After peak torque your VE table should start to go down much like a dyno sheet.
Here try this. When logging you need to do steady state and don't include any major increase of the TPS. Try to do 1k rpm at first and slowly work your way up. Using the brake pedal for when you need to do the upper rpms will be your friend.
http://r.search.yahoo.com/_ylt=A0SO8...8T.kRr28z7dxg-
Ps, if your tuner said there was something pulling timing and can't tell you why then go elsewhere.
Here try this. When logging you need to do steady state and don't include any major increase of the TPS. Try to do 1k rpm at first and slowly work your way up. Using the brake pedal for when you need to do the upper rpms will be your friend.
http://r.search.yahoo.com/_ylt=A0SO8...8T.kRr28z7dxg-
Ps, if your tuner said there was something pulling timing and can't tell you why then go elsewhere.
Last edited by danieloneil01; 04-26-2014 at 06:10 PM.
04-27-2014, 06:39 PM
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Staging Lane
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VE table needs work and 28 degrees is more than most. You're commanding a 11.7 after 2k rpm and it was 13 on the dyno? After peak torque your VE table should start to go down much like a dyno sheet.
Here try this. When logging you need to do steady state and don't include any major increase of the TPS. Try to do 1k rpm at first and slowly work your way up. Using the brake pedal for when you need to do the upper rpms will be your friend.
http://r.search.yahoo.com/_ylt=A0SO8...8T.kRr28z7dxg-
Ps, if your tuner said there was something pulling timing and can't tell you why then go elsewhere.
Here try this. When logging you need to do steady state and don't include any major increase of the TPS. Try to do 1k rpm at first and slowly work your way up. Using the brake pedal for when you need to do the upper rpms will be your friend.
http://r.search.yahoo.com/_ylt=A0SO8...8T.kRr28z7dxg-
Ps, if your tuner said there was something pulling timing and can't tell you why then go elsewhere.
Im not sure if anyone messed with the tune before I had the car, I will be spending some time this week just tuning as much as I can. The dyno I just did a few pulls but I didnt have the tune look into anything in the tune file. I'm getting ready to throw ported 241s and a cam in shortly but Im trying to learn the basics of tuning before I go all in, Thanks for everyone help!
04-27-2014, 06:42 PM
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Looking at the trims can be helpful plus or minus 7,8,9 is pretty common and fairly normal. At +15 you for sure have lean it will spit codes at +25
But trims do not tell the whole story you can have them fairly close and still run lean WOT. PCM will add positive trims to commanded PE which should be pretty rich if
the fuel system can deliver. Fuel pressure check @ KOEO and idle 58?
Put the gauge under the windshield wiper and do a WOT blast. Fuel pressure WOT
in the 40s could go that lean on a stock tune but your dyno numbers do not really reflect that.
But trims do not tell the whole story you can have them fairly close and still run lean WOT. PCM will add positive trims to commanded PE which should be pretty rich if
the fuel system can deliver. Fuel pressure check @ KOEO and idle 58?
Put the gauge under the windshield wiper and do a WOT blast. Fuel pressure WOT
in the 40s could go that lean on a stock tune but your dyno numbers do not really reflect that.
the other problem I noticed is the racetronix fuel pump starts to whine when it gets hot... not sure why. I have heard different stories about it. I will be checking fuel pressure soon. when the car first starts it is silent but after an hour or two of driving the fuel pump starts whining loud. but the car never has issues with power... IDK?
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04-27-2014, 07:08 PM
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That is too lean imo. Shoot for 12.5-12.8 AFR. My 98 TA had 28 degrees of advance at WOT bone stock from the factory. The knock sensors on the 98 LS1 are different compared to the later LS1's and were notorious for false knock. I would see 3-4 degrees of knock at times even when the car was tuned.
04-27-2014, 07:38 PM
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That is too lean imo. Shoot for 12.5-12.8 AFR. My 98 TA had 28 degrees of advance at WOT bone stock from the factory. The knock sensors on the 98 LS1 are different compared to the later LS1's and were notorious for false knock. I would see 3-4 degrees of knock at times even when the car was tuned.
Yea I noticed during my last data log it was seeing close to 4 degrees of knock , I will be changing the tune this week and see if that helps out, I also pulled some other bin files from Hp tuners site and compared them to mine. Going to richen up the wot this week as well.
04-27-2014, 07:40 PM
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VE table needs work and 28 degrees is more than most. You're commanding a 11.7 after 2k rpm and it was 13 on the dyno? After peak torque your VE table should start to go down much like a dyno sheet.
Here try this. When logging you need to do steady state and don't include any major increase of the TPS. Try to do 1k rpm at first and slowly work your way up. Using the brake pedal for when you need to do the upper rpms will be your friend.
http://r.search.yahoo.com/_ylt=A0SO8...8T.kRr28z7dxg-
Ps, if your tuner said there was something pulling timing and can't tell you why then go elsewhere.
Here try this. When logging you need to do steady state and don't include any major increase of the TPS. Try to do 1k rpm at first and slowly work your way up. Using the brake pedal for when you need to do the upper rpms will be your friend.
http://r.search.yahoo.com/_ylt=A0SO8...8T.kRr28z7dxg-
Ps, if your tuner said there was something pulling timing and can't tell you why then go elsewhere.
The dyno pulls I did this past week I ran two with the exhaust cut out closed but the last one I ran with it open maybe that had more to do with it ?
