Rise of the Phoenix

iTrader: (27)

Any way to fix that without a cam change? Would a FAST setup fix it and allow me to run this cam?

ddnspider

iTrader: (26)

It gives you a much better shot, more air in more air stays in the chamber. Don't take what I say as gospel though, I just get paid to think analytically and rule out variables until a solution is reached. In this scenario it seems reasonable that the combo just isn't working together and I think valve events and the speed of the airflow is coming into play. Its all about cylinder pressure in the end and i think the cam with that i/e isnt as good as it could be. It's a Tick cam, was that when Martin was working there? If so what does he say about the change in the graph from the header swap?

Rise of the Phoenix

iTrader: (27)

Martin hasn't weighed in yet. I hope he sees this and does. What you are saying is basically what Kent (builder and tuner) is saying. He said the intake is acting like a velocity stack in the higher RPM'S and it just cannot keep up with the heads and headers. Seems as if the valve events are not optimal for this setup. A different cam on a 112 or 113 LSA may not have this issue of the intake being such a restriction.

nmass399

Your running it in speed density correct? Look at the new tune in the ve table vs the old tune with the other headers and see what it looks like. Is it putting more fuel in or less at those rpms?

Rise of the Phoenix

iTrader: (27)

Yes, it's in Speed Density. I'll find out. What could that tell us if it's putting in less or more fuel at the higher RPM's?

ddnspider

iTrader: (26)

I cant help but notice the thread down from falxzzr that seems to have similar issues at high RPM. Same dyno and tuner, and if the AFR and spark are what they are, is it possible the dyno has an issue at high speed or is there examples from that dyno where they'll pull cleanly to something highish. He also has a new motor, was the same builder the one who put your cam in?

jmilz28

iTrader: (13)

I think you're on to something here. I'd take this car to a known reasonable dyno and see what it puts down. My thinking is there is something fundamentally tweaked with this dyno.

kinglt-1

iTrader: (26)

I just do not see the LS6 choking power per SE. It's is documented to have made well into the 450whp range with a vast range of H/C 346 setups over the years. Will a Fast make more power yes, but the LS6 is not a bad piece. If we were talking about the LS1 intake then yea this theory would seem plausible. The motor should still peak around 63-6400 even with the LS6 and carry.

I think the dyno is wacked...take the car to a different one. Or head to the track and see what it traps.

Rise of the Phoenix

iTrader: (27)

I see what you're saying about FALXZZR and his dyno sheet. His graph, like mine, stops making power before it theoretically should. That could be an issue with the dyno, who knows.

In regards to Kent, who did my cam and heads swap, as well as a lot of the tuning, I do not doubt his ability at all. He's done tons of LSx builds and has an 8 second LSx himself that he built and tuned.

9sectruck

iTrader: (9)

The car feels awesome on the street. The car does not lay over on dyno nor does it sound like it has any issues during the pulls.

There may be something with the dyno settings that is causing low hp numbers in the upper rpm.

The graph from one pull to the next pull with header swap and new mufflers. (no dyno settings change) seem like it falls off to fast. Yes the dyno may be off but the car def lost power up top.

As for a clog or restriction on exhaust there is no smell or noise to indicate a blockage.
The car did need more fuel on big end to get back to the 12.7afr after swap was done. Timing has not been changed from these two pulls. 29deg.
Nathan. We will strap the car down tonight and do another hit. Maybe another set of eye and ears will pick up something..

9sectruck

iTrader: (9)

The initial hit on street and dyno around 2800rpm the car will go 12.0afr then climb straight to 12.6-12.7afr. Timing ramps in from 22-25 up to 29 by 4900rpm

9sectruck

iTrader: (9)

yes i built both cars. And tuned both. Op car was done 3-4yrs ago on street tuning and fallzer was done on dyno this last month...
Im not the big name tuner by any means. But doing for about 6yrs now. (knock on wood just blowing my own **** up) nobody elses.
I find the stopping points with my own car.. Lol

Rise of the Phoenix

iTrader: (27)

If it needed more fuel on the big end, doesn't that mean it's making more power which necessitates more fuel, or am I wrong there.

9sectruck

iTrader: (9)

The very last graph with dyno recalibrated. This after re-tuning car with more fuel up top to get afr back in the 12s. The car still falls off at 57-5800rpm. Im going to scan map readings on the car with key on not running to verify the map is around 102-105kpa then do another pull with car and see if the car is pulling vacuum. (90-98kpa) this should tell us if intake is choking the car down.

9sectruck

iTrader: (9)

Yes nathan it should. More air more fuel should have net more power

slow trap

iTrader: (22)

i don't have the graphs but mine has the same issue of dropping off quicker up top now than with the 1 3/4" headers. it really sucks dropping time and money into mods that in reality should pick up power but they wind up not doing squat. now i may also be thinking ddnspider may possibly be onto something. we need the cam gurus and advanced fellows in here to help.
rise of the phoenix's car on the same dyno carried better with the 1 3/4 " so i doubt it is the dyno.valve timing and over scavenging may be the issue but i would hate to change cams and still not be where it needs to be.heck,look at people claim true duals with an x pipe helps scavenging and picks up power.i am lost on my setup as well as one like this guy's. good luck on finding your lost h.p bro.

ddnspider

iTrader: (26)

Not knocking you as a tuner by any means. If anything a setup like this on a dyno is cake to tune especially at WOT so I doubt its an issue in the tune.

Rise of the Phoenix

iTrader: (27)

I sent the dyno graph to Brian Tooley this morning to get his opinion on whether or not it's the cam causing this.

Rise of the Phoenix

iTrader: (27)

Kent, that sounds like a good idea. It will help narrow things down for sure.

fst100

iTrader: (5)

something else to think about since you had mentioned cam overlap which sounds interesting.
http://www.lunatipower.com/Tech/Cams/CamSpecTerms.aspx
particularly under the "What does it do?". makes one wonder that a cam with 111 like a MS4 make topend power would then need to rev really high (with a lift .649/.609 IIRC) along with proper gearing make power, right?