Performance MOds for 05 GXP
#31
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Lets not forget, there are cams available for this car right from GM. We give up 25 hp by having the SLS "torque" cams instead of the STS "hp" cams. The car still feels like it needs to be on cam before pulling really hard, so I don't know how much we are really getting by having the torque cams.
Best North* test I ever saw was in 2002 by Motor Trend. Their STS ran 60 in just under 6.5 and the quarter in 14.5. Considering that the GXP is lighter, a 300hp GXP should easily be able to do the same.
Best North* test I ever saw was in 2002 by Motor Trend. Their STS ran 60 in just under 6.5 and the quarter in 14.5. Considering that the GXP is lighter, a 300hp GXP should easily be able to do the same.
#33
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The LD8 was detuned in a couple ways, not just the cam. Cracking open a Northstar is a dicey, odds side with snapping headbolts than not. And then switching cams without being able to alter fuel/air/spark because the PCM is locked will only make the engine worse, not better. For now it'* useless to surmise anything unless you can afford a custom PCM, and the expertise and expense of knowing how to program/tune it. Hate to be the pessimist here, but like I said, we've been here for 5 years bangin our head against the wall. In that time span, a few performance companies have made statements that didn't materialize. Including intense. I'm not jumping up and down with anticipated joy here.
If you really want to get a lurch form your GXP, Call Zex. I run 75 wet shot without a hiccup. About are much as you can spray.
If you really want to get a lurch form your GXP, Call Zex. I run 75 wet shot without a hiccup. About are much as you can spray.
#36
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Hope you do, Man. Don't like to be Nancy negative. But been chewing the GXP ideas "fat" to long. It'* lost it'* flavor for me over the years.
To bad you dont live closer to Alberta. We have a guy very good with PCM'* that thinks he can get around the PCM. Needs a gunea pig.
My opinions.
About the cam'*. The LD8 is called detuned. And the word implies alot of things. Some wrongfully perceived. Gm stated when they developed the LD8, it was "tuned" for a lighter chassis and a quicker Final gear ratio. You have to consider the whole picture of HP vs Torque. And that isnt stressed enough. Or known adequately by people who sit and BS. Also our more modern LD8 has coatings throughout that allow it to need/use much lighter oil. Something that needs to be considered when you start mix and matching parts.
You stating common misconceptions here and I have to correct them. From GM specs.
Notice the torque of the LD8. And you want to believe that reverting to a L37 setup will help our cause. Not logical. You are stating misgiven facts perceived by some that were here 4 years ago and moved on to spread their armchair physics.
Also, you say the L37 cams are available for our car. They started the same engine but split and were independently developed from then on. And that was way back in 1994. I have never seen credible evidence that those cams will, "slip into our car". I realize you are basing what you say on what you hear, but do some research. Can you provide us with a link showing where to get them and that they list as viable for the LD8? I doubt it.
The are alot of forums out there, and some have just plain bad info. Alot of us here actually check things out before we speak. Because here, people are allow to question and evaluate things.
To bad you dont live closer to Alberta. We have a guy very good with PCM'* that thinks he can get around the PCM. Needs a gunea pig.
My opinions.
About the cam'*. The LD8 is called detuned. And the word implies alot of things. Some wrongfully perceived. Gm stated when they developed the LD8, it was "tuned" for a lighter chassis and a quicker Final gear ratio. You have to consider the whole picture of HP vs Torque. And that isnt stressed enough. Or known adequately by people who sit and BS. Also our more modern LD8 has coatings throughout that allow it to need/use much lighter oil. Something that needs to be considered when you start mix and matching parts.
You stating common misconceptions here and I have to correct them. From GM specs.
-
- L37 high-output 300 hp (224 kW) and 295 ft·lbf (400 N·m)
- LD8 high-torque 275 hp (205 kW) and 300 ft·lbf (407 N·m)
Notice the torque of the LD8. And you want to believe that reverting to a L37 setup will help our cause. Not logical. You are stating misgiven facts perceived by some that were here 4 years ago and moved on to spread their armchair physics.
Also, you say the L37 cams are available for our car. They started the same engine but split and were independently developed from then on. And that was way back in 1994. I have never seen credible evidence that those cams will, "slip into our car". I realize you are basing what you say on what you hear, but do some research. Can you provide us with a link showing where to get them and that they list as viable for the LD8? I doubt it.
The are alot of forums out there, and some have just plain bad info. Alot of us here actually check things out before we speak. Because here, people are allow to question and evaluate things.
#37
With regard to '05 and up, the peak TQ on the L37 dropped to 285 @ 4400 or 288 @ 4500 RPM depending on the application.
The LD8 is listed at 300ft/lbs @ 4000 RPM.
More torque at a lower RPM. That is not all bad!!
BTW, the following is some information regarding the cam specs and the differences. Thought they might be of interest to the conversation:
2004 - 2008 Cadillac (LD 1.68 Rockers
• Camshaft Lobe Duration @ 0.006 in Lift - Exhaust 236°
• Camshaft Lobe Duration @ 0.006 in Lift - Intake 242°
• Camshaft Lobe Lift - Exhaust 0.2339 in
• Camshaft Lobe Lift - Intake 0.2421 in
• Camshaft Lobe Overlap @ 0.006 in Lift 6.4° GM has it listed @ 1.98°
• Camshaft Timing @ 0.006 in Lift
• Intake Opens 1.3° BTDC
• Intake Centerline 117.0° ATDC
• Intake Closes 237.9° ATDC
• Exhaust Opens 226.1° BTDC
• Exhaust Centerline 111.0° BTDC
• Exhaust Closes 5.1° ATDC
.
2004 - 2008 Cadillac (L37) 1.68 Rockers
• Camshaft Lobe Duration @ 0.006 in Lift - Exhaust 246°
• Camshaft Lobe Duration @ 0.006 in Lift - Intake 251°
• Camshaft Lobe Lift - Exhaust 0.2339 in
• Camshaft Lobe Lift - Intake 0.2421 in
• Camshaft Lobe Overlap @ 0.006 in Lift 10.9° GM has it listed @ 2.04°
• Camshaft Timing @ 0.006 in Lift
• Intake Opens 0.3° ATDC
• Intake Centerline 122.0° ATDC
• Intake Closes 246.0° ATDC
• Exhaust Opens 229.3° BTDC
• Exhaust Centerline 110.0° BTDC
• Exhaust Closes 11.2° ATDC
Ken
The LD8 is listed at 300ft/lbs @ 4000 RPM.
More torque at a lower RPM. That is not all bad!!
BTW, the following is some information regarding the cam specs and the differences. Thought they might be of interest to the conversation:
2004 - 2008 Cadillac (LD 1.68 Rockers
• Camshaft Lobe Duration @ 0.006 in Lift - Exhaust 236°
• Camshaft Lobe Duration @ 0.006 in Lift - Intake 242°
• Camshaft Lobe Lift - Exhaust 0.2339 in
• Camshaft Lobe Lift - Intake 0.2421 in
• Camshaft Lobe Overlap @ 0.006 in Lift 6.4° GM has it listed @ 1.98°
• Camshaft Timing @ 0.006 in Lift
• Intake Opens 1.3° BTDC
• Intake Centerline 117.0° ATDC
• Intake Closes 237.9° ATDC
• Exhaust Opens 226.1° BTDC
• Exhaust Centerline 111.0° BTDC
• Exhaust Closes 5.1° ATDC
.
2004 - 2008 Cadillac (L37) 1.68 Rockers
• Camshaft Lobe Duration @ 0.006 in Lift - Exhaust 246°
• Camshaft Lobe Duration @ 0.006 in Lift - Intake 251°
• Camshaft Lobe Lift - Exhaust 0.2339 in
• Camshaft Lobe Lift - Intake 0.2421 in
• Camshaft Lobe Overlap @ 0.006 in Lift 10.9° GM has it listed @ 2.04°
• Camshaft Timing @ 0.006 in Lift
• Intake Opens 0.3° ATDC
• Intake Centerline 122.0° ATDC
• Intake Closes 246.0° ATDC
• Exhaust Opens 229.3° BTDC
• Exhaust Centerline 110.0° BTDC
• Exhaust Closes 11.2° ATDC
Ken
Last edited by Kersh; 03-03-2010 at 11:50 AM.
#38
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