Help with my setup, opinions on power output etc
03-30-2022, 04:40 PM
#21
TECH Enthusiast
What valve springs did BTR recommend. Before i went solid roller i had a BTR cam very similiar and i used pac 1208x open pressure of 460lbs. Mayb your onto the issue
03-30-2022, 05:35 PM
#22
TECH Enthusiast
For what it’s worth and for anyone still checking in on this thread, I believe I have narrowed down the loss of top end power.
tuner said when he turned up the rev limiter in the Holley pcm it wouldn’t rev beyond 6700. He asked if I had my 2 step plugged in still (was using that as a rev limiter prior to Holley) because it sounded it it was bouncing off of it.
this coupled with peak power being made at 6k and dropping off as rpm increases
and the TFS springs having a 400lb open pressure, me running .646” lift with stainless valves (vs titanium)
valve float is my issue.
I called cam motion and they recommended a spring kit that I’ll order and install, and report back to this thread for anyone that cares.
tuner said when he turned up the rev limiter in the Holley pcm it wouldn’t rev beyond 6700. He asked if I had my 2 step plugged in still (was using that as a rev limiter prior to Holley) because it sounded it it was bouncing off of it.
this coupled with peak power being made at 6k and dropping off as rpm increases
and the TFS springs having a 400lb open pressure, me running .646” lift with stainless valves (vs titanium)
valve float is my issue.
I called cam motion and they recommended a spring kit that I’ll order and install, and report back to this thread for anyone that cares.
The following 2 users liked this post by grubinski:
99 Black Bird T/A (03-31-2022), Che70velle (03-30-2022)
03-30-2022, 05:54 PM
#23
TECH Fanatic
The following users liked this post:
99 Black Bird T/A (03-31-2022)
03-30-2022, 09:16 PM
#24
For what it’s worth and for anyone still checking in on this thread, I believe I have narrowed down the loss of top end power.
tuner said when he turned up the rev limiter in the Holley pcm it wouldn’t rev beyond 6700. He asked if I had my 2 step plugged in still (was using that as a rev limiter prior to Holley) because it sounded it it was bouncing off of it.
this coupled with peak power being made at 6k and dropping off as rpm increases
and the TFS springs having a 400lb open pressure, me running .646” lift with stainless valves (vs titanium)
valve float is my issue.
I called cam motion and they recommended a spring kit that I’ll order and install, and report back to this thread for anyone that cares.
tuner said when he turned up the rev limiter in the Holley pcm it wouldn’t rev beyond 6700. He asked if I had my 2 step plugged in still (was using that as a rev limiter prior to Holley) because it sounded it it was bouncing off of it.
this coupled with peak power being made at 6k and dropping off as rpm increases
and the TFS springs having a 400lb open pressure, me running .646” lift with stainless valves (vs titanium)
valve float is my issue.
I called cam motion and they recommended a spring kit that I’ll order and install, and report back to this thread for anyone that cares.
I would swap out that mid-rise intake for a MSD or Hi-ram. That thing is proven to make less power over other intakes. I'd bet even a stock LS7 manifold would make more power than that thing.
03-30-2022, 11:23 PM
#25
I don't think that's your issue. I ran a very similar combo to that on a LS7. Stock bottom end, ported and milled stock heads, BTR .660 springs (~400lb open pressure), Morel lifters, stock manifolds, and stock intake. It made 530whp and like 480wtq. I put on 1-7/8 headers and it it picked up 15whp and 30wtq. Then I put on a Mamo ported MSD and NW102 and it picked up 35whp and 45wtq.
I would swap out that mid-rise intake for a MSD or Hi-ram. That thing is proven to make less power over other intakes. I'd bet even a stock LS7 manifold would make more power than that thing.
I would swap out that mid-rise intake for a MSD or Hi-ram. That thing is proven to make less power over other intakes. I'd bet even a stock LS7 manifold would make more power than that thing.
However, that’ll be something to look into if springs don’t work. I’m sure I could pick up power with a ported msd and 2” primary LTs but I think my biggest concern is the valve train
Last edited by The0nlyon3; 03-30-2022 at 11:32 PM.
03-31-2022, 02:43 AM
#27
your worked over stock ls7 heads have lighter intake valves being that they are titanium. About 40-50 grams lighter than mine which are stainless. That’s a lot at 6500+.
However, that’ll be something to look into if springs don’t work. I’m sure I could pick up power with a ported msd and 2” primary LTs but I think my biggest concern is the valve train
However, that’ll be something to look into if springs don’t work. I’m sure I could pick up power with a ported msd and 2” primary LTs but I think my biggest concern is the valve train
The following users liked this post:
G Atsma (03-31-2022)
03-31-2022, 10:38 AM
#29
I didn't have titanium valves. I had stainless valves. Even with larger camshafts, after I upgraded from the BTR Stage 3, I didn't have issues with valve float. I don't think your issue is valve float, unless the springs weren't setup correctly and you actually have way less open pressure than advertised. I would check install height on the current springs and shim them if needed, rather than a whole new set.
the heads came assembled from TFS. My engine builder checked them… what that entails is beyond me.. I assumed a spring that came with aftermarket heads would be able to withstand higher lift cam.
400lbs open pressure is not that much for a cam that has .646” lift. The springs are not able to shut the intake valve fully before the intake lobe makes a 360° turn. Not only is the spring supposed to close the valve before the next cycle, it also has to maintain pressure on the other valve train components like pushrods and lifters which have mass.
I know you disagree but i’m basing my decision on experiences I’ve had with this set up.
Between the dyno graph and the fact my engine won’t rev past 6700rpm and it sounding like it’s hitting a 2 step rev limiter, tells me it’s valve float. Also, the springs were over looked when assembling the engine.
I’d rather spend $600 and be in the same boat as before than spend 3k between a ported Intake and TB and 2” primary LTs and be in the same boat.
im sure that stuff would help me achieve the ultimate max power out of this thing but the major issue is the springs.
It’s a free country so we can disagree as we please. Like I said, I’ll definitely post the results once I get them and will have ZERO issue admitting I was wrong if that’s the case.
03-31-2022, 08:11 PM
#30
The second cam I went to was the TSP 4.2 cam. 248/260, .657"/.655", 111 LSA, 108 ICL
Then I went to the RPM B3 cam. 243/258 .660"/.660" 114+3 LSA
It's definitely worth the time to make sure the springs are installed correctly. Hope it helps your issue. If not, just one less thing you have to worry about.
Then I went to the RPM B3 cam. 243/258 .660"/.660" 114+3 LSA
It's definitely worth the time to make sure the springs are installed correctly. Hope it helps your issue. If not, just one less thing you have to worry about.
03-31-2022, 09:35 PM
#31
The second cam I went to was the TSP 4.2 cam. 248/260, .657"/.655", 111 LSA, 108 ICL
Then I went to the RPM B3 cam. 243/258 .660"/.660" 114+3 LSA
It's definitely worth the time to make sure the springs are installed correctly. Hope it helps your issue. If not, just one less thing you have to worry about.
Then I went to the RPM B3 cam. 243/258 .660"/.660" 114+3 LSA
It's definitely worth the time to make sure the springs are installed correctly. Hope it helps your issue. If not, just one less thing you have to worry about.
03-31-2022, 10:40 PM
#32
I liked it when I had that setup. It drove great and made great power. I made 650whp with that cam, ported heads, 12.2:1 compression, holley hi ram, e85 and a monster clutch. I ended up selling the engine and going turbo.
The following users liked this post:
The0nlyon3 (04-04-2022)