So you automatically assume user configurable tools are crap? Not surprising, as I have learned to assume the same thing of a lot of users who configure things. Too bad the tools seem to get the brunt of the hate.

 

I think you quoted me on accident because I said nothing of the sorts.

 

So your current combo is this:

Engine: 416 LT stroked
Compression: 10.5:1
Heads: Stock
Fuel: E85
Cam: Blower grind
Turbos: Twin Comp 68/71 1.06
Trans: 8L90E

When you reference the car that made 1200rwhp, you said it ran the same turbos, and was it the same fuel? Are both combos the same a/a or a/w setup?

Key question for me is how many lbs of boost did the other car have to make to achieve 1200rwhp?

 

I quoted your post intentionally, but perhaps projected my viewpoint of a lot of users onto the intent of your post. User configurable tools can be very repeatable if they are properly used, but they have the ability to be manipulated at the whim of whatever jackass is using them. Apologies if it seemed I was putting words in your mouth.

 

This... that cam has way too much exhaust duration. The turbos should be sufficient to go 7300 7500 on that motor. However, im pretty sure you are losing power due to excessive overlap. Like the quote above, most turbo grinds generally run around an 8 degree split between intake and exhaust on an efficient combo. Additionally, the timing events for a blower cam is not ideal for a turbo due to backpressure made in the hotside. I'd bet if you changed the cam to something like 238/246 on a 114.5 or 116 you'd pick up power everywhere and the system as a whole be happy.

 

Your cam has 22 degrees overlap. That's way too much for those turbines on that big of an engine. You need to cut that number in half at least and it will wake up.

 

Measuring pre turbine back pressure should show if that cams overlap is choking those turbos out.

 

Man, it has to be. Everything on his combo looks great except for the cam. The intake/exhaust split is too wide and it has 22 degrees overlap.

 

I was specifically talking about user configurable dynos and how the results that come out of those are NOT comparable to another dyno. It's all up to how the end user sets them up and I've never seen two of them read the same. Then you get into where a "shop" starts to inflate numbers to sell a product or a service and claim they can make more power then anybody else and before you know it you have cam only LS3s making 500 rwhp with their "tuning". I guess my whole point, and what I said was, I immediately throw the results of a user configurable dyno out the window as you can't compare them to different dynos. About the only dynos that you can compare now a days are plain old 2WD dynojets since you can't skew how they read unless you **** with the weather station, but then that's obvious when you see the conditions on the printout.

 

Yes that is correct and everything was the exact same except cam, heads and intake. Other car was on around 25 I believe and mine stopped making power at 20.

 

That is really what I am thinking/hoping. I am really wanting to change the cam to something better suited and see what it does but don't want to waste the money if it won't pick up much, hence my thread here.

 

I believe its the cam. My sbe ls3 made almost 1100 on 16 lbs with stock heads, vs 6766 twins, fast high ram and a smallwood solid roller. That cam is 236/244 114.5 with btr ultimate rpm springs. After lash the duration is actually around 232 240 with about 6 or 8 degrees overlap. It peaked around 7500 with that combo. Your engine has larger turbines than mine so it should peak close to that on your 416 or maybe a little lower, but the hp number should be higher. I would just about bet the farm that if you changed the cam, couples with the right valve spring your power goals would be reached. Too much overlap on a turbo car is way worse than too little. It's the cam and springs. Gotta be.

 

Others may have said it, but boost is entirely different betweeen Supercharger and turbo. The first thing to acknowledge is exhaust back pressure, Ambient air is 14.7 lbs. pushing against the intake and exhaust valves. Exhaust is pushng against 14.7 lbs. PLUS the exhaust systems bends and length. A supercharger is free of the pressure ratio. Spin to the world and make boost. A turbo must balance its freedom on the intake side with the restriction it introduces on the hotside. Hence the difference in overlap. For this reason a Supercharger or Nitrous cam is very different from a turbo cam

 

I think I am going to swap it and see what it does, I don't know what else it could be.

 

Perfectly said.

 

Thanks for the information, I was thinking it was cam related but I am not a mechanic by any means and definitely not a turbo wizard by any stretch of the imagination. I am going to swap it and retune it and see what it does.

 

That's what I'd do. I'd be willing to bet an eyebrow that it would pick up power everywhere.

 

I may have missed it but have you responded to what NicD was saying about the Dynocom dyno?

 

I didn't because I really don't have anything to say about it, my trap speed lines up with the power I made on the dyno with the weight of the car so I trust the number it gave.

 

That is what counts. Hell, I have trapped 129mph in a 4000lb car before that only dynoed 509hp. We found out old dual roller mustang dynos can have serious wheelspin issues. The trap speed vs weight is an excellent indicator of actual power.