Cam change?

[GetSmart]

2013 SS L99

I recently asked an installer to swap out my GPI SS1 to a BTR Stage 3 cam, the specs for each cam are:

GPI SS1 VVT - 219/231, .638/.629 on 112 LSA. Tuned by Ryan at GPI

BTR Stage 3 LS - 229/244, .631/.615 on 113 LSA. Tuned by local person.

I can't remember what the overlap are for both of these cams. But I remember he said there is +4 advance for the 113 LSA.

My problem is....I don't feel any more power from the BTR stage 3 cam! Also, the chop is not as choppy and the sound is not as loud to me. The acceleration seems to be a little better and the shifting is a little smoother, but overall the power is not noticeable, in fact, it seems like it has less power to me. Another weird thing to me is that at stop lights it has very good manners, does not buck or surge, seems to do it even less than the GPI cam, I thought I would need torque converter to handle the Stage 3.

I would think going from a SS1 to a Stage 3 cam, even though its two different makes, the difference would be noticeable.

Anyone have some insights?

Thanks,

John

[InFiD3ViL]

The GPI cams really are great cams, and nobody can tune them like Ryan can. Maybe the difference in power was made up by a combination of the VVT and Ryan's expertise. I know the tuner can adjust the tune a bit to get things more/less choppy, to a degree. I had asked Ryan to give me more of a natural/random lope instead of the repeating Brap-Brap-Brap and it came out great.

I'm assuming that BTR Stage III cam is a Non-VVT cam, correct?. You got more duration/overlap on the BTR cam of course, but the GPI cams are fairly high lift (VVT or not), especially compared to other companies similar staged cams. Maybe specs wise it is kind of a wash? That BTR cam likely shines above 6000 rpm compared to the GPI. Interesting nonetheless.

Just curious, since you removed VVT why didn't you stay with GPI and go with one of their LS3 cams and let them tune you again? Just trying to change things up?

[FasNuf]

A quality tuner makes a huge difference for sure.

[GetSmart]

Just to try something different and local. My GPI SS1 cam had some nice power for a small cam. The problem was the push rods were too long and the trunions shredded sending needles in the heads. The exhaust valves were beat and the rockers were worn down. Started making a clacking sound, knew it was a broken rocker sound. I felt Ryan did a great job with the tune, but the local installer didn't think so, he said the transmission was off.

Ryan gave me a mean chop and lots of power and torque.

The installer probably didn't want to fuss with the VVT/phaser tuning, but I thought the difference would still be noticeable even though the VVT was being deleted.

How do you think I should approach this matter with the installer? The specs for the two cams are similar, with the Stage 3 having more duration. The installer said his tuner tunes with the MAF sensor off and on.

Thanks.

[Inferno dogg]

Originally Posted by GetSmart

Just to try something different and local. My GPI SS1 cam had some nice power for a small cam. The problem was the push rods were too long and the trunions shredded sending needles in the heads. The exhaust valves were beat and the rockers were worn down. Started making a clacking sound, knew it was a broken rocker sound. I felt Ryan did a great job with the tune, but the local installer didn't think so, he said the transmission was off.

Ryan gave me a mean chop and lots of power and torque.

The installer probably didn't want to fuss with the VVT/phaser tuning, but I thought the difference would still be noticeable even though the VVT was being deleted.

How do you think I should approach this matter with the installer? The specs for the two cams are similar, with the Stage 3 having more duration. The installer said his tuner tunes with the MAF sensor off and on.

Thanks.

You still have the stock stall converter?

[GetSmart]

Originally Posted by Inferno dogg

You still have the stock stall converter?

Yes I do, I know, kinda weird.

[TheFlyingBananaSS]

Those cams are very close specs. But the GPI has that high lift which looks as though they knew what they were doing when they designed their cam line. Good news for me as I have a SS2 going in my baby.

[TheFlyingBananaSS]

Oh I believe the GPI is +6

[TheFlyingBananaSS]

My SS2 is 228/235 .637/.637

[GetSmart]

Originally Posted by TheFlyingBananaSS

My SS2 is 228/235 .637/.637

wow, thats a pretty aggressive cam for a stage 2. Yah, the installer was telling me before that the lift was too high, but the BTR stage 3 lift is high also. I didn't know just a few more degrees or inches makes so much difference between a stage 1 and stage 3. But Ryan's tunes are really aggressive and makes the car fun to drive. Right now I have a bigger cam and yet it's not as fun to drive.

[JakeS]

In regard to stage 3 cams. When they recommend a torque converter, is that to reduced the forward creep?

[InFiD3ViL]

Originally Posted by JakeS

In regard to stage 3 cams. When they recommend a torque converter, is that to reduced the forward creep?

That's a part of it. Mine pushes pretty bad with the stock convertor. The other part is that if the convertor and cam are properly matched, it allows you to get right into the cams powerband.

Since you mentioned a Stage 3 or aggressive cam, let's assume that cam starts making power at 3000 rpm. But your stock convertor is rated 1800 rpm. You will be starting out in a dead area of your power band with that convertor, since your cam isn't making much power at 1800-3000 rpm. The higher rated converter gets you into your power band immediately. Without the convertor the car will feel lazy in the lower rpms. Someone else will have a better way of explaining this hopefully.

[Warship2k15]

Originally Posted by InFiD3ViL

That's a part of it. Mine pushes pretty bad with the stock convertor. The other part is that if the convertor and cam are properly matched, it allows you to get right into the cams powerband.

Since you mentioned a Stage 3 or aggressive cam, let's assume that cam starts making power at 3000 rpm. But your stock convertor is rated 1800 rpm. You will be starting out in a dead area of your power band with that convertor, since your cam isn't making much power at 1800-3000 rpm. The higher rated converter gets you into your power band immediately. Without the convertor the car will feel lazy in the lower rpms. Someone else will have a better way of explaining this hopefully.

What he said!
Get a converter with a decent stall the car be much quicker and more fun to drive.

[InFiD3ViL]

Keep in mind his SS1 was a VVT cam, which is lower lift and duration than the non VVT LS3 SS1-SS3 cams. But apparently, that VVT makes up for the lower numbers in the curve.

My Stage 1 GPI SS1 LS3 cam (Non-VVT) is .647/.638, 224/237 (My cam card numbers, advertised is 646/.637). That's pretty high lift for a stage 1, but only 7º overlap and moderate duration. The GPI LS3 SS3 is the same lift specs as mine but duration is 233/253. Compare that to his new BTR Stage 3 cam...quite a bit larger. His new BTR cam is a lower lift, but higher duration/overlap cam than the SS1 VVT. Add the VVT and Ryan's tuning into the mix...not surprised that he isn't feeling a big difference. Obviously I understand there are other things in play here.

GPI SS1 VVT : .638/.629, 219/231
GPI SS1 LS3 : .646/.637, 224/237
GPI SS3 LS3 : .646/.637, 233/253
BTR Stage 3 : .631/.615, 229/244

This was just an example to show that you can't really compare stages from one cam manufacturer to another. You are always best served to grind the cam based on your end power goals (and head flow capability, of course) It was also to show how beefy GPIs cams are lol. This isn't even mentioning their Stage IV NFC cam.