Ya it's such a hard pill to swallow after all the effort, time and money spent. I thought I put together a strong combo that would take nitrous, boost whatever and go strong for a long time with tons of torque for a fun street car that should run strong at the track. I dont understand what is holding it back. Unless I've missed something in the engine or trans tune. I can post my tune file (HP Tuners) if anyone is up for taking a quick glance to see if I've missed something..

 

I understand this completely about building a combination that we expect to do better. Good luck man, hopefully its something simple

 

I guess the one thing I was hoping someone could explain to me is the fact that I used the same base tune on the same dyno when I switched intakes. Logging everything I saw a gain of mass air hertz, a gain in cylinder airmass, and I had to add over 12% more fuel to reach the same 12.5 afr, and i made THE EXACT SAME POWER! I was also logging zero TCC slip as it was locked, and also zero trans slip.. this is what makes zero sense. More air pplus more fuel equaled nothing

 

If you have a file yes please upload. Maybe there will be something simple. I doubt it because you seem like the type who has really paid attention. The power is not what is bugging me. It is the torque.

 

You know after reading the responses to my questions regarding AFR and atomization of the fuel itself - I'm really leaning towards a Fueling issue myself - that, or something is up with the transmission. Because, as the OP stated, there should have been a clear/obvious difference in the two graphs when he changed intake manifold. I believe there is something not related to the engine that's causing a "bottleneck" . I don't know much about auto's though, so I couldn't say what. How does one verify slippage when dyno'ing through an Auto? I assume slippage in this case is referring to the internal gearings/converter?

And I hate to be the one to wear the tinfoil hat but - have you had the chance to dyno another car on this dyno? will it even let it exceed those torque figures? Hell maybe something is wrong with the dyno itself? lol

Also, not trying to beat a dead horse here but... *what's the compression ratio on this engine*?

 

I will definitely upload my tune soon as I get home, thanks! Ya the low torque is what is truly baffling I agree
I'm able to log slip as I use HP Tuners, so the trans slip pid compares input shaft rpm to output shaft rpm along with the known gear ratio, in this case 4th gear which is 1.15. I show zero slip coming from the trans, and the same with the converter. Unless there is truly something wrong with the trans and it is showing false data... I too am limited in these 6l80 trans. The only slip I see on the street is due to the stall as it is very VERY loose. It is going in for a refresh this winter when the car is down, and will be getting the new fuel pump. I know fuel pressure drops to 45psi at the tip of the pull, but where peak torque is, it was still above 55psi. This shouldnt have effected power production at this point. Like the other guy from Australia who has literally the same combo as me except ported LS3 heads vs my ported LS7, his torque is almost 90rw higher. That is what this combo was exactly built for. A heavy G8. 515rwtq is insane and doesnt make sense to me. I will have that tune up soon

Also, the compression ratio is 11.5:1

 

The heads were ported by Blackwell race engines, very very good machinist. I had him put 2.180 intake valves in

my dyno chart here shows 393 rwkw = 526rwhp and 808nm = 595 lb ft. The rev limiter was set at 6800rpm . After this i put on a fast 102 and made 549rwhp and roughly same lb ft

Yes id say very close to same engine specs. I dont know how much diff gears change dyno figures. For this dyno i had t56 with 3.27diff
Once i sort out my crank no start issue ill be on dyno with upgrades, mamo 265heads, mamo msd and 259/265 solid roller . Ill post dyno graph so you can see result

 

If you are adding fuel and seeing more air flow, dyno could have been adjusted differently for correction factor, tire could be low on air pressure, to many variables from day to day. Honestly see what it does at the track and tweak it their.

 

That's some crazy torque for only having a 3:27 rear gear.
I'm at 1150nm at the rear with 3:91 gears.
Also seems to me Blackwell know what they are doing.
In regards to your upgrades I was thinking of going the same route except with 235cc heads from Mamo which suit my bore and stroke.
With the solid roller is that a low lash solid from cam motion?
I was looking at doing a ported fast 102mm from Mamo.
I did ask him how this one feels compared to a ported msd.
He did say the fast has better velocity and will be stronger in the low and mid range but the msd will be a little better higher up in the rev range.

 

The cam is a crow cams solid, builder picked it , im sceptical but will run it up and see how it goes. If doesnt do what i want i'll swap to a cam motion solid.

 

How much lash is in a crow cams solid?
If it's .020 or .030 you are going to have one noisy engine.
If it's for track only it doesn't matter.
A normal race solid is also going to be brutal on the valvetrain and you will need to check your lash much more frequently.
If you are going to be driving this thing on the street at least 50% I would definitely go the low lash from cam motion.
It's a mild lobe designed for the street with no lash adjustments necessary for a long time.
It runs very quiet and the lobes are still higher in intensity than even the craziest hydraulic roller lobes.
Cam specs chosen are good if it was a cam motion solid as you only lose about 6 degrees of duration on each end.
With more lash you will lose even more duration.

 

Lash for the cam is .016. Its not a race cam ,lobes not to aggressive . Designed for street. Will know more once ive driven it

 

Oh ok.
That's not too bad then.
I still think the USA made stuff is better.
Cam motion use a stronger and harder steel.
What are you looking for with this cam which will be the deciding factor?
You will lose about 9 degrees of duration on each end which will turn it in to a 250/256 cam once warm.
If you have time, create a thread for your engine.
I really want to see your results.

 

Just wondering if these cars had fuel pressure issues? Or was pressure fine and they still picked up going to a return style system? I am running my car with a dead headed rail but returning from the regulator right before the rail. Fuel pressure is dead on (I log it) but I still don't like the idea of fuel only entering one side of the rail. Looking for some motivation to add a return to the rail and change my fuel lines

 

I installed an electric fuel pressure gauge near my reg which gives me a digital reading inside the car after I was having coil pack issues at high rpm and car was hitting rpm limiter too soon. It's nice to mash the throttle and knowing you still have 60 psi fp showing inside the car (the electric gauge reads 2 more psi than the mechanical gauge on the reg ).

Like Darth said IR gun before you do anything else. But these gm coils can deteriorate and still work well at most rpm's making you think the coils aren't the culprit but they will spark weak at higher cylinder pressures.

Also, I had one new in box MSD wire reading 1000 ohms (all others read under 50 ohms as typical) and I pulled the boot on the coil end first to see what's up and the wire wasn't crimped properly, but you could barely tell that it wasn't. All I did was squish the terminal with a pair of pliers in hope I fix it, and then it was good, read under 50 ohms.

As for your fuel pressure, no way it can be dropping in the 40's and your injectors are working properly. These new school things are too smart for their own good sometimes, it is keeping your afr target because it's smart enough to do so, doesn't mean you are making max HP. Injectors will be opening all messed up.

If it were me, before you do anything else, IR gun your primaries from a cold start, but don't just trust that alone, check every wires resistance with multimeter just incase if you haven't already because you can still have spark in a cylinder but weakens under high cylinder pressure, and get your fuel pressure rock steady. And if it were me I'd buy a new set of oem coils if yours are over 100k miles old and put them on, because I no longer trust that well used gm ls coils are worth a ****.

 

Ok so I for sure just figured it out!! The issue was I felt like I was being "limited" to 530whp and 518tq no matter which intake or runner length was being used. Obviously the dropping fuel pressure needs to get resolved, and I'm ordering a new DeatschWerks pump this weekend. Mostly I couldn't understand how to very different runner lengths produced the exact same power curve. It wasnt until I started thinking about my old setup (6.0 w/ls3 heads, cam, headers etc) that I remembered I was having funny oscillating airflow values at upper rpms until I read that people started using a honeycomb insert to straighten out the airflow and give the MAF a smoother reading. Well it seemed to work decently at the time. Fast forward to this LSX454 build, and I completely forgot the HONEYCOMB IS STILL IN THE MAF TUBE!!! No wonder I couldn't exceed a certain power number as airflow was being greatly restricted!!! I just went out to the car and pulled it out. It was literally sitting almost exactly sideways in the MAF tube as well!! I cant believe I never thought about this until now!! 😖. So it's time for a street tune then back to the dyno!! I included a picture so you all can laugh along with me.

 

I removed that thing from my MAF when I first got my car....it didn’t offer any noticeable power gains or responsiveness.

But if yours was sitting sideways at an angle that would block a good bit of airflow.

 

Hopefully this will fix it.
Keep us updated and post a dyno sheet.

 

Honeycomb helps quite a lot with the MAF... especially if using the LS3/7 style cartridge. It helps even out the airflow. It's not a restriction.

 

Really? I figured with the airflow this setup should be making, that honeycomb would be some sort of a restriction for sure