T&T w/truck from Carolina Dragway Jan16th - Page 3

gearmesh, inc. · 01-19-2011, 11:42 AM

I have heard that with a turbo, if you have the means if retarding the ignition timing while on the 2-step and/or transbrake, the extra heat in the exhaust from late ignition will help spool up the turbo even more.

I have even heard of specific turbo cams that have a late closing of the exhaust valve. The exhaust valve doesn't close until the piston is part way up on the exhaust stroke so that you get a high velocity push of exhaust gas to drive the turbine side of the turbo harder. This makes for a wider lobe separation and a more steetable cam, too. I have heard a lot of praise for the folks at Cam Motion concerning their turbo grinds.

Carlrx7 · 01-19-2011, 09:58 PM

there is got to be a way to get that done inside the tune without having to use a standalone.

Carlrx7 · 01-19-2011, 10:02 PM

Rob,

Do you have one of these tables?

Clutch Fuel Cut Off Spark. mainly used to reduce the popping on decel, since you are now auto, i say toggle the clutch engauge switch and see if your timing changes, if so, you owe me lots of steak!

-Carl

BAD BOB · 01-19-2011, 10:24 PM

they normally would cut out fuel which would cause it to lean out, atleast thats how my efi live works. looked into doing something with mine like that but was told it was not the thing to do

Carlrx7 · 01-19-2011, 11:12 PM

well, there is a fuel cut table as well, also several ways to trick the ecu to think its in a specific gear, and each of those tables have an rpm spark or fuel cut limit.

-Carl

Foose04 · 01-20-2011, 12:06 AM

Hey Carl, yeah I actually played with it when the truck had the stick in it. However, it was a really rough 2step at best (slow to resume after cutting off) I have my doubts on how well it would work at the low RPMS i'd be using it at. Thanks for the heads up though.

Carlrx7 · 01-20-2011, 12:57 AM

Ps. I hope that 4.8 came with stainless steel exhaust valves with all this late combustion.

Foose04 · 01-20-2011, 01:05 AM

Inconel...didn't you know I got a factory freak. Jim Bob at the GM plant that day hooked me up for shits & giggles.

01-19-2011, 11:42 AM	#41
gearmesh, inc. creepy azz cracka Join Date: Nov 2008 Location: Summerville Posts: 1,587	I have heard that with a turbo, if you have the means if retarding the ignition timing while on the 2-step and/or transbrake, the extra heat in the exhaust from late ignition will help spool up the turbo even more. I have even heard of specific turbo cams that have a late closing of the exhaust valve. The exhaust valve doesn't close until the piston is part way up on the exhaust stroke so that you get a high velocity push of exhaust gas to drive the turbine side of the turbo harder. This makes for a wider lobe separation and a more steetable cam, too. I have heard a lot of praise for the folks at Cam Motion concerning their turbo grinds. __________________ "I came into this world kicking, screaming,and covered in someone else's blood, I have no problem leaving the same way!" ÔÇ£If you carry a gun, people will call you paranoid. ThatÔÇÖs ridiculous. If I have a gun, what in the hell do I have to be paranoid about?ÔÇØ -Clint Smith, Thunder Ranch.

01-19-2011, 09:58 PM	#42
Carlrx7 Senior Member Join Date: Apr 2010 Location: Ladson,SC Posts: 3,813	there is got to be a way to get that done inside the tune without having to use a standalone. __________________ Dark Aladdin

01-19-2011, 10:02 PM	#43
Carlrx7 Senior Member Join Date: Apr 2010 Location: Ladson,SC Posts: 3,813	Rob, Do you have one of these tables? Clutch Fuel Cut Off Spark. mainly used to reduce the popping on decel, since you are now auto, i say toggle the clutch engauge switch and see if your timing changes, if so, you owe me lots of steak! -Carl __________________ Dark Aladdin

01-19-2011, 10:24 PM	#44
BAD BOB Senior Member Join Date: Mar 2008 Location: SUMMERVILLE Posts: 3,681	they normally would cut out fuel which would cause it to lean out, atleast thats how my efi live works. looked into doing something with mine like that but was told it was not the thing to do __________________ IM BAD BOB

01-19-2011, 11:12 PM	#45
Carlrx7 Senior Member Join Date: Apr 2010 Location: Ladson,SC Posts: 3,813	well, there is a fuel cut table as well, also several ways to trick the ecu to think its in a specific gear, and each of those tables have an rpm spark or fuel cut limit. -Carl __________________ Dark Aladdin

01-20-2011, 12:06 AM	#46
Foose04 Senior Member Join Date: Feb 2010 Posts: 965	Hey Carl, yeah I actually played with it when the truck had the stick in it. However, it was a really rough 2step at best (slow to resume after cutting off) I have my doubts on how well it would work at the low RPMS i'd be using it at. Thanks for the heads up though. __________________ 12 GMC Denali HD: 4x4, 12" Bullet Proof, 24x12 American Forces, 40x15.50 Toyo M/T's, h&s mini max, deleted, 5" axle dump, S&B intake,tractions bars, air bags. 04 GMC 1500RST: TMS Iron 347/S480/4l80E - 9.63@143.22 05 GMC 2500HD: LLY@372HP/669TQ, 4x4, 8" FabTech, 4.56 gears & 37" Toyo M/T's

01-20-2011, 12:57 AM	#47
Carlrx7 Senior Member Join Date: Apr 2010 Location: Ladson,SC Posts: 3,813	Ps. I hope that 4.8 came with stainless steel exhaust valves with all this late combustion. __________________ Dark Aladdin

01-20-2011, 01:05 AM	#48
Foose04 Senior Member Join Date: Feb 2010 Posts: 965	Inconel...didn't you know I got a factory freak. Jim Bob at the GM plant that day hooked me up for shits & giggles. __________________ 12 GMC Denali HD: 4x4, 12" Bullet Proof, 24x12 American Forces, 40x15.50 Toyo M/T's, h&s mini max, deleted, 5" axle dump, S&B intake,tractions bars, air bags. 04 GMC 1500RST: TMS Iron 347/S480/4l80E - 9.63@143.22 05 GMC 2500HD: LLY@372HP/669TQ, 4x4, 8" FabTech, 4.56 gears & 37" Toyo M/T's