The Only 3300 lb. Buick V6 in the 8s using...

[Alky V6]

A lot of things wrong with this run, yet, 8.76 on 1.83, 1.5 valves.
Unfortunately, I didn't have the DS sensor on the car yet, so it's very hard to determine where the launch starts.
Judging by where the timing comes back in, the nitrous shuts down at 5421 rpm and 178.5 kPa MAP.
You can see a lot of leaning going on. Enough to cause engine rpm surging during the last portion of the run. The problem there was a hole in a tee fitting in the signal line to the referenced fuel pressure regulator, AND a burnt electrical terminal at the voltage booster for the fuel pump.
The 4 bar MAP sensor wasn't on the car yet either. You can see that at the end of the run the 3 bar MAP sensor maxed out on me. No telling what the boost was at the end of the run. I don't imagine it was a whole lot more than what the trace shows.
The boost control curve was a modified version of what I use at my 1/8 mile home track. You can see the dip in boost during second gear that I would normally need at my home track to maintain traction. Although, the dip is a whole lot less in this control curve. If I had any idea, I would have had the boost ramp up to a higher level during 1st gear and level out for the whole run. This was a case where I had only 2 practice and 2 qualifying runs to hit as close to 8.50 as possible, having only done most of my testing on an 1/8 mile track.

 

[Alky V6]

My car makes best power with an a/f ratio of 10.8:1 on a gasoline scale at 30 psi boost. You can see by the datalog that the a/f was fluctuating wildly due to the fuel supply problems I was having at the time. The lowest point in the a/f ratio trace is 10.3:1. The highest point is above 14.64:1. It's obvious that the engine was dangerously lean for the majority of the run. Yet, she pulled off an 8.76 ET, even with the fueling problems and the less than optimized boost control curve. I find that very interesting.

 

[4timesT]

With so many things wrong with the car during that run maybe your boost gauge was bad too and you were running 40 psi without even knowing it....

 

[Street Lethal]

A lot of things wrong with this run, yet, 8.76 on 1.83, 1.5 valves...

I would like to see the results w/the stock sized intake valve. I was fooling around with a set of stock iron heads recently, and I'd like to see just how deep in the nines I can get running an LC2 in a 3rd Gen F-Body, but w/the stock valves though. I think the key here isn't the actual size of the valve, per se, but the velocity of the charge. Here are some before and after's....

 

[Alky V6]

With so many things wrong with the car during that run maybe your boost gauge was bad too and you were running 40 psi without even knowing it....

The tee fitting that had the hole in it fed the fuel pressure regulator and the boost gauge in the dash. During a run, I never have time to look at the gauge, anyway. I now have the signal line go straight to the fuel pressure regulator, and the boost gauge is sitting in the dash not being used.
The MAP sensor that feeds a signal to the ECM to control fueling was on its own separate signal line off the intake manifold. That signal line had no leaks. The MAP trace line in the datalog is via the MAP sensor and ECM. It's a good reading.

 

[turbo nasty]

Ever consider having another good tuner put a second set of eyes on the tune. Not saying you arent capable just sometimes another angle can help. May cost a few bucks but spending is racing

 

[Alky V6]

I would like to see the results w/the stock sized intake valve. I was fooling around with a set of stock iron heads recently, and I'd like to see just how deep in the nines I can get running an LC2 in a 3rd Gen F-Body, but w/the stock valves though. I think the key here isn't the actual size of the valve, per se, but the velocity of the charge. Here are some before and after's....

That sounds like a very worthy goal, and challenging. Keep us posted!

 

[Alky V6]

Ever consider having another good tuner put a second set of eyes on the tune. Not saying you arent capable just sometimes another angle can help. May cost a few bucks but spending is racing

At the level I'm presently at with these small valved heads, how much could I possibly gain? And who else has the experience with a configuration similar to mine? No one.
I think that if I were to pay someone to study my tune, they would probably end up learning more from my tune than the benefit I would gain from him helping with my tune. And I would be the one paying to bring him up to speed with what I'm doing? Nah. That doesn't sound right to me. I've done just fine up to this point, and I'm not even done. I still have avenues mapped out that need exploring. We're not done yet. I have chassis work continuing, and a little more dialing in of the fuel map still. Particularly, the high boost region (above 31 psi) that I haven't even touched yet.

 

[Alky V6]

In case anyone is wondering why I haven't really explored above 31 psi yet, I want the chassis worked out to my satisfaction. If anyone has ever seen my car run, they understand why that is. Add to that, the track I test on is not the best place to be pushing the boost.

 

[Alky V6]

Ever consider having another good tuner put a second set of eyes on the tune. Not saying you arent capable just sometimes another angle can help. May cost a few bucks but spending is racing

I should add one other very important point.
My whole configuration is based on the advantages that can be had from resonance tuning a turbocharged engine. No one has shown me that they understand or even slightly comprehend the merits of pressure pulse tuning with a turbocharged engine, much less, how to accomplish it. That tuner, if he exists, is certainly not on this site.

 

[Alky V6]

I'm curious. Does anyone have a clue as to how much additional boost a person can see in the intake runner using resonance tuning? I'm not talking about the general intake plenum MAP level, I'm talking about the boost advantage obtained in the intake runner tract associated with pressure pulse tuning.

 

[Mike E]

It's going to have some relation to where resonant frequency, intake valve events, number of blades on the compressor wheel wheel and compressor wheel speed meet. This many variables would make this pressure wave vs. resonant frequency a moving target. But each time you hit it, the compressor wheel slows down and your back out of that specific situation. Unless you match that frequency and amplitude on the turbine side. I don't see how an engine that operates at varrying RPM to be able to truly take advantage of this. There may be finite points where this has some affect, but in the rpm sweep of a drag racing pass how usefull is it really? Do the collum of air and the droplets of fuel resonate at the same frequency? Most likely not because of differing densities, the have different intertia. So you most likely get to points where they cancel each other out.

I'm sure high dollar pro-stock engines take advantage of pulses in the intake runner, but they don't develop measureable pressure because of it. If someone measured this sine wave, it would have a very small amplitude. Adding boost to the sine wave moves the entire graph up, but the difference between the peak and average boost does not change. Any engine that takes advantage of this only does so in a pretty narrow rpm band and would most likely need a narrow rpm band between gear changes (ie: 5 speed pro stock car). If you want in depth knowledge of this phenomena, you should look into a book about acoustics. It's the same theories, a collumn of air vibrating with different inputs.

 

[Mike E]

If that collum of air and collum of fuel are vibrating at different frequencies or have different pressure waves, wouldn't that have some affect on how each fills the cylinder? If so, wouldn't that change air fuel ratio in the cylinder by some small amount? Is the positive affect of the pressure wave enough to overcome the negative affect of air fuel ratio changing from perfect?

 

[Alky V6]

Take a look at the old Busch Indy light Buick V6 engines. Particularly, the exhaust manifolding. Now those are some tuners that understood resonance tuning.

The boost advantage from resonance tuning in the intake runner itself over the simple intake plenum reading is a matter of not fractions of a psi, but in whole psi numbers. And not just one or two psi.

 

[Mike E]

Indy lights cars probably operated in a very narrow rpm band on the straight sections of track where they needed the power.

 

[Alky V6]

True the majority of the advantage of resonance tuning is narrow, within a 1500 rpm range, but what if that range was tuned to where you really could take advantage of it, or really needed it?

 

[Dusty Bradford]

Like he said. A drag car running up through an rpm range is totally different.

Those guys also work an entire year to find 10hp. Dynamics of a drag car and engine can't begin to be compared to other forms of racing. The power you make from the heads solely lies in the backpressure result of the turbo being so large. It really is that simple.

Need more proof. Look into why twin turbo's make more power than a single even when the same 30psi of boost is generated on the intake. Efficiency and back pressure. You have basically sized a single turbo to duplicate the hp gains seen by twins.

 

[Alky V6]

Like he said. A drag car running up through an rpm range is totally different.

Those guys also work an entire year to find 10hp. Dynamics of a drag car and engine can't begin to be compared to other forms of racing. The power you make from the heads solely lies in the backpressure result of the turbo being so large. It really is that simple.

Need more proof. Look into why twin turbo's make more power than a single even when the same 30psi of boost is generated on the intake. Efficiency and back pressure. You have basically sized a single turbo to duplicate the hp gains seen by twins.

But then how do you explain the performance I was having with the T76?

 

[Alky V6]

True the majority of the advantage of resonance tuning is narrow, within a 1500 rpm range, but what if that range was tuned to where you really could take advantage of it, or really needed it?

Using my case as an example, what rpm range do you think I chose to resonance tune to?

 

[Alky V6]

Like he said. A drag car running up through an rpm range is totally different.

Those guys also work an entire year to find 10hp. Dynamics of a drag car and engine can't begin to be compared to other forms of racing. The power you make from the heads solely lies in the backpressure result of the turbo being so large. It really is that simple.

Need more proof. Look into why twin turbo's make more power than a single even when the same 30psi of boost is generated on the intake. Efficiency and back pressure. You have basically sized a single turbo to duplicate the hp gains seen by twins.

So you think Pro Stock doesn't resonance tune their combinations?