What did I do???
What did I do??? Hello, I just changed the cam in my 2001 GMC Sierra RC 2wd stepside and it feels lazy??? These are my modifications done. LQ9 6.0, LT headers w/ electric cutouts, 4.10 w/ Eaton posi 3500 stall, shift kit in tranny w/ cooler. I bought the LQ9 as a new crate motor then installed Thunder Racing 224 .563 at 112. This also has the Beehive springs and there pushrods. This setup made this truck perform amazingly fast. It had excellent response and a nice lopey idle but more to the mild side. Well, I decide to change the cam one more time so I went with Texas-Speed Comp TQRV2 cam which has a 232/234 and a .598 lift with a 113 LSA. I had them also retune the PCM. I just started it tonight and drove it for about 25 miles and I'm somewhat disappointed. It feels kinda lazy compared to the other cam and it's not much bigger. I just wanted more of a racy idle which also is kinda the same also. What has happened?? Do I have to give the computer time to adjust?? Please if anyone has any suggestions please send them my way.
Originally Posted by alconk
Hello, I just changed the cam in my 2001 GMC Sierra RC 2wd stepside and it feels lazy??? These are my modifications done. LQ9 6.0, LT headers w/ electric cutouts, 4.10 w/ Eaton posi 3500 stall, shift kit in tranny w/ cooler. I bought the LQ9 as a new crate motor then installed Thunder Racing 224 .563 at 112. This also has the Beehive springs and there pushrods. This setup made this truck perform amazingly fast. It had excellent response and a nice lopey idle but more to the mild side. Well, I decide to change the cam one more time so I went with Texas-Speed Comp TQRV2 cam which has a 232/234 and a .598 lift with a 113 LSA. I had them also retune the PCM. I just started it tonight and drove it for about 25 miles and I'm somewhat disappointed. It feels kinda lazy compared to the other cam and it's not much bigger. I just wanted more of a racy idle which also is kinda the same also. What has happened?? Do I have to give the computer time to adjust?? Please if anyone has any suggestions please send them my way.
Rollinna65 pretty much nailed it. The bigger cam makes less horsepower in the lower rpm range which makes your truck feel sluggish down low. The tradeoff is more horsepower in the higher rpm range. Your gas mileage should be lower now too.
Shifts points are still at 6 grand or maybe it's 6200. They told me that I would notice more mid and loose some bottom end which I was willing to sacrifice (it's all over the road until around 40mph). I did notice the speedo climbs faster from 70 on up but just don't feel it??? It that true about the PCM learning the new program?? They told me it takes about a hour of driving to do so???
Originally Posted by alconk
Shifts points are still at 6 grand or maybe it's 6200. They told me that I would notice more mid and loose some bottom end which I was willing to sacrifice (it's all over the road until around 40mph). I did notice the speedo climbs faster from 70 on up but just don't feel it??? It that true about the PCM learning the new program?? They told me it takes about a hour of driving to do so???
