8.1 Vortec, throttle body, adapter, harness
10-02-2016, 02:58 PM
#1
8.1 Vortec, throttle body, adapter, harness
Working on my 8.1 Vortec intake, for my '03 3500.
Can I use the LS7 throttle body that Summit lists on their website, with the Casper's adapter harness, and a 4 bolt mounting plate?
The plan is to cut the intake, fully port it, remove the EGR (I neither need nor want it), move the PCV system (to prevent oil consumption), and install one of the bigger throttle bodies, such as an LS2 or LS7. I'd just as soon TIG weld a mounting plate for the throttle body, instead of using an adapter, since the adapter is just going to move the throttle body out toward the fan shroud, requiring an even tighter radius on the air inlet tube from the MAF sensor. I'd almost TIG weld a cast aluminum 90 degree elbow on it, but I think that might put the MAF and the throttle body too close together.
The Casper's harness is PN 108115.
The LS2 throttle body is PN 12570790.
The LS7 throttle body is PN 12605109.
The Wilson mounting plate is PN 087001.
Can I use the LS7 throttle body that Summit lists on their website, with the Casper's adapter harness, and a 4 bolt mounting plate?
The plan is to cut the intake, fully port it, remove the EGR (I neither need nor want it), move the PCV system (to prevent oil consumption), and install one of the bigger throttle bodies, such as an LS2 or LS7. I'd just as soon TIG weld a mounting plate for the throttle body, instead of using an adapter, since the adapter is just going to move the throttle body out toward the fan shroud, requiring an even tighter radius on the air inlet tube from the MAF sensor. I'd almost TIG weld a cast aluminum 90 degree elbow on it, but I think that might put the MAF and the throttle body too close together.
The Casper's harness is PN 108115.
The LS2 throttle body is PN 12570790.
The LS7 throttle body is PN 12605109.
The Wilson mounting plate is PN 087001.
10-02-2016, 07:58 PM
#2
I've welded on an L29 cast upper before. These things are hardened, heat treated to make them stiffer. Before welding it you'll need to soften it up or it will be very prone to heat cracking.
You can tell by the sound wrapping it if it's hardened. Suspend from a metal hook and knock gently with another piece of metal. The more ring the harder it is, the more thud the softer.
What's worked for me is putting the hardened cast aluminum into the oven supported on a stainless steel tray and then turning it on and heating to 750 degrees fahrenheit using the clean cycle. (Most ovens won't set higher than 550.) Once temp is reached turn the oven off and walk away. Do not open. Leave the cast aluminum inside to cool off as slowly as the oven does and it will soften.
To weld on it wrap the whole thing in a welding blanket or something else high-temp fire resistant so that the entire piece stays hot while working with it. Heat it up with a torch before welding helps too since the thick cast will so rapidly pull heat away from the puddle. When finished leave wrapped and let cool down slowly.
To re-harden you'll have to heat it up in the oven again and then remove and quench in oil. The probability of cracking in the process is present, and opening an oven than hot is dangerous in itself, so there's some risk. (Some ovens have a thermal door lock when the clean cycle is activated.)
Heating and cooling may distort the whole thing slightly and it may be necessary to machine flat the mounting surfaces.
The adapter isn't really such a bad option, considering.
You can tell by the sound wrapping it if it's hardened. Suspend from a metal hook and knock gently with another piece of metal. The more ring the harder it is, the more thud the softer.
What's worked for me is putting the hardened cast aluminum into the oven supported on a stainless steel tray and then turning it on and heating to 750 degrees fahrenheit using the clean cycle. (Most ovens won't set higher than 550.) Once temp is reached turn the oven off and walk away. Do not open. Leave the cast aluminum inside to cool off as slowly as the oven does and it will soften.
To weld on it wrap the whole thing in a welding blanket or something else high-temp fire resistant so that the entire piece stays hot while working with it. Heat it up with a torch before welding helps too since the thick cast will so rapidly pull heat away from the puddle. When finished leave wrapped and let cool down slowly.
To re-harden you'll have to heat it up in the oven again and then remove and quench in oil. The probability of cracking in the process is present, and opening an oven than hot is dangerous in itself, so there's some risk. (Some ovens have a thermal door lock when the clean cycle is activated.)
Heating and cooling may distort the whole thing slightly and it may be necessary to machine flat the mounting surfaces.
The adapter isn't really such a bad option, considering.
10-02-2016, 08:10 PM
#3
I probably won't weld it myself, although I probably could. It's pretty likely that I'll just let the guy who does my racing cylinder heads do it, I figure if he can weld my aluminum big block heads, he can handle this job. He'll be doing most of the porting anyway.
There are already a couple of spots in the air duct where it hits the fan shroud, moving everything forward with an adapter will only make that worse, and I'm trying to improve air flow.
There are already a couple of spots in the air duct where it hits the fan shroud, moving everything forward with an adapter will only make that worse, and I'm trying to improve air flow.
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