Acceleration off the line
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Junior Member
Joined: Sep 2001
Posts: 82
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From: Woodlands, Texas, USA
Acceleration off the line
Okay, I've made some pretty good improvements in my ol' truck. Got the BLM's very close to 128 and I've improved acceleration for passing, but I just can't figure out how the get more acceleration from a stand still. It doesn't hesitate, it just bogs down.
Is it a matter of adjusting pump shot, or should I be looking at spark advance too?
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1991 Chevy C2500HD 5.7L HD. 16147060 ECM
Mods: Crane PowerMax 2030 cam 204I 214E @ .050 and 423I 446E lift, Jacobs Pro Street Ignition System. Using DataMaster and TunerCat with $85 ECM files.
Is it a matter of adjusting pump shot, or should I be looking at spark advance too?
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1991 Chevy C2500HD 5.7L HD. 16147060 ECM
Mods: Crane PowerMax 2030 cam 204I 214E @ .050 and 423I 446E lift, Jacobs Pro Street Ignition System. Using DataMaster and TunerCat with $85 ECM files.
Supreme Member
Joined: Jun 2000
Posts: 7,554
Likes: 1
From: In reality
Car: An Ol Buick
Engine: Vsick
Transmission: Janis Tranny Yank Converter
<font face="Verdana, Arial" size="2">Originally posted by davidjon_99:
Okay, I've made some pretty good improvements in my ol' truck. Got the BLM's very close to 128 and I've improved acceleration for passing, but I just can't figure out how the get more acceleration from a stand still. It doesn't hesitate, it just bogs down.
Is it a matter of adjusting pump shot, or should I be looking at spark advance too?
</font>
Okay, I've made some pretty good improvements in my ol' truck. Got the BLM's very close to 128 and I've improved acceleration for passing, but I just can't figure out how the get more acceleration from a stand still. It doesn't hesitate, it just bogs down.
Is it a matter of adjusting pump shot, or should I be looking at spark advance too?
</font>
AE
Timing table
PE enables
VE table
Spark adder
Need to start doing one change at a time, and take notes about things. Notes are very important.
Senior Member
Joined: May 2001
Posts: 502
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From: Hollywood, FL
Car: 78 Regal
Engine: 82 FBod LG4 305, 730 ECM
Transmission: M20
Axle/Gears: 4.10
I thought I have read in this forum where the trucks have a delay for accelerating so that they don't peel out when towing a boat or something like that. You know, so that power is smooth in coming in and not abrupt or jerky, kinda like me.
Thread Starter
Junior Member
Joined: Sep 2001
Posts: 82
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From: Woodlands, Texas, USA
<font face="Verdana, Arial" size="2">Originally posted by hectorsn:
I thought I have read in this forum where the trucks have a delay for accelerating so that they don't peel out when towing a boat or something like that. You know, so that power is smooth in coming in and not abrupt or jerky, kinda like me.</font>
I thought I have read in this forum where the trucks have a delay for accelerating so that they don't peel out when towing a boat or something like that. You know, so that power is smooth in coming in and not abrupt or jerky, kinda like me.</font>
------------------
1991 Chevy C2500HD 5.7L HD. 16147060 ECM
Mods: Crane PowerMax 2030 cam 204I 214E @ .050 and 423I 446E lift, Jacobs Pro Street Ignition System. Using DataMaster and TunerCat with $85 ECM files.
Member
Joined: Feb 2001
Posts: 166
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From: canada
<font face="Verdana, Arial" size="2">Originally posted by davidjon_99:
That was probably me who posted that. I turned that "feature" off (set the WOT delay to 0) and now I'm trying to figure out what else I can do to get a little more acelleration. I will be limited by the heads they put on these trucks, but I should at least be able to beat a Yugo off the line.
what gears are in your truck? is it a limited slip? tire size? all this will determine how your truck starts out from a stop. also trucks have a low stall converter which limit the rpm so you don't spin excessively when pulling from a stop. my truck has a stock converter, posi, 4:11 gears, 35 x 10.50 x 16.5 tires and because of my stall it is very hard to spin the tires on dry pavement, cannot build the rpm fast enough. wet pavement is another storey. i am also alot heavier, 6000lbs. 500lb diffs.
</font>
That was probably me who posted that. I turned that "feature" off (set the WOT delay to 0) and now I'm trying to figure out what else I can do to get a little more acelleration. I will be limited by the heads they put on these trucks, but I should at least be able to beat a Yugo off the line.
what gears are in your truck? is it a limited slip? tire size? all this will determine how your truck starts out from a stop. also trucks have a low stall converter which limit the rpm so you don't spin excessively when pulling from a stop. my truck has a stock converter, posi, 4:11 gears, 35 x 10.50 x 16.5 tires and because of my stall it is very hard to spin the tires on dry pavement, cannot build the rpm fast enough. wet pavement is another storey. i am also alot heavier, 6000lbs. 500lb diffs.
</font>
Thread Starter
Junior Member
Joined: Sep 2001
Posts: 82
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From: Woodlands, Texas, USA
I've got 3.73 with limited slip and stock converter in the 4L80E. It is a long bed extended cab with 14 bolt rear end so there is a bunch of mass that has to get moving. I'm probably expecting more out of this thing than it can deliver off the line.
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