Good..... Maybe try keeping it to yourself. Humble pie its whats for breakfast
The Only 3300 lb. Buick V6 in the 8s using...
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Good..... Maybe try keeping it to yourself. Humble pie its whats for breakfast
Nah. That wouldn't be any fun.
I'm like you. I like to share my accomplishments.
I think it's due to the density of the charge air the motor's ingesting. Between the cooling effects of your intercooler and using alcohol for fuel, that 31 psi of air your motor is ingesting is much denser than what other turbo cars are ingesting at 31 psi. That would also explain why you're able to do it with the small intake valve. Oh and let's not forget you're also shooting a good amount of spray while boosting up, which cools not only the air but also the intake manifold.
Now when you make 1300-1500 HP from a 1.5 liter production block like BMW did back in the 80s, you let us know.
Now when you make 1300-1500 HP from a 1.5 liter production block like BMW did back in the 80s, you let us know.
Street Lethal
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In my opinion, I feel that it is the symmetry of your entire setup, meaning everything working in harmony that is giving you your numbers, not just one thing in particular. The nitrous off the line and the size of the turbo is the key though, as the nitrous is helping you to achieve that low sixty foot with such a big turbo, while the sheer size of the turbo, once spooled off the line, being able to carry you through the entire length of the track. The smaller valves are irrelevant in my opinion, as your cam specs, cylinder head flow, stall speed, gearing and tune are apparently on the money. Oh, and let's not forget the driver apparently knowing what he is doing... :wink:
As I've already mentioned, typically you want the ports in an alcohol engine larger than what you'd have in a gasoline engine. The reason for that is the extra volume of fuel that the alcohol engine has to ingest. Over 2 times more fuel. This extra fuel displaces air that would be ingested. Does the temperature of the alcohol/air charge (denser charge) make up for the small ports and the extra amount of fuel that has to pass through the port, displacing much needed intake air? I doubt it.
It is true that an alcohol engine can develop about 15% more power than a gasoline engine due to the properties of the fuel along with the amount of fuel that's being ingested, but that only occurs if the engine configuration is changed to take full advantage of the alcohol fuel, like larger ports.
One important change that must be done is the static compression ratio. The extra CR is needed to heat the intake charge to a proper temperature in the cylinder for a more efficient burn of the mixture. This is why alcohol engines also run best when heated to at least 155 degrees F, and preferrably to around 195-200 degrees F. Blown alky engines typically use a static CR of 10-12:1.
One could also use dynamic CR to get the charge up to temperature, but if I'm only boosting 30 psi with a 9.25 static CR, there really isn't much advantage compared to a gasoline engine that is also boosting 30 psi with say 9.0:1 CR. For me to really make the alcohol fuel shine, I need to push the boost to about 40 psi. I don't dare do that yet because of the track conditions at my home track.
Another thing about alcohol fuel. You can actually overcool an intake charge. Temperature control of the air/fuel charge is a delicate balancing act. As I explained above, by the time the charge is ready to be lit, the burn will be most efficient when the temperature of the charge is preheated within a certain range. If a charge starts out entering the cylinder at a lower intake temperature, it means that more static compression would have to be used to elevate the temperature of the charge during compression and before ignition. If the needed static, or dynamic compression isn't there, the charge will not reach the optimum temperature for the most efficient combustion. This is actually the main reason my form of ALS works.
The BMW engine. Are you really trying to compare my small 2 valve engine to a 4 valve per cylinder engine? Do you realize what rpms they were running? The exotic fuel they were running? The boost levels they were running during qualifying runs? There is no way anyone will get a Buick V6 up to 10 hp per cid. Especially with a single 1.835 int and 1.5 exh valve.
Dang! I like this post. Thanks.
Street Lethal
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DonWG said:
I still don't think the valves are that big of a deal though because peak numbers don't really mean a thing. Although a separate animal, I can tell you that Marty Stromberger ran in the nine's with a set of 991 truck heads that came equipped with 1.72/1.50 in his 350-SBC. He too needed nitrous off the line to get his two turbo's (stock LC2 turbo's) spooled. Pretty cool read for those who are interested, and want to compare...;
1988 Pontiac Firebird - Featured Vehicle - Car Craft Magazine
[video=youtube;P5e2cWmX5Z0]http://www.youtube.com/watch?v=P5e2cWmX5Z0[/video]
Just to show that you can overcool an intake charge, let me use my nitrous/methanol system as a perfect example. I'm presently up to a 360 hp shot into the engine. 60 hp shot per cylinder. And, another 65 hp shot just before the turbine housing. The only reason I don't use a larger nitrous shot into the engine, not that I haven't already tried it, is because any larger shot size into the cylinders and the power output begins to nose over and drop. The charge ends up being too cold at the time when ignition of the mixture needs to occur.
Two extra cylinders and more cubes. Not really the best comparison, but still interesting what others are doing with small valves. Thanks for posting.
Street Lethal
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DonWG said:
I agree, but it's essentially the very same argument over on some of the other boards. Guys are building SBC's with nothing less than 1.94 intake valves thinking that that is what it will take to run in the nines w/their turbo's, while someone like Marty comes along and runs the same numbers that they are with a much smaller intake valve, with everyone then scratching their heads in confusion not understanding why. Either way, job well done, your Grand National hauls @ss...
One other difference I noticed. It sounds like from the article that he's injecting the nitrous the whole pass. That would definitely make a big difference. Probably why he's not having to use big boost numbers, too.
Street Lethal
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DonWG said:
The speed of sound decreases with the increase in density....
Street Lethal
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4timesT said:
If arao-engineering would get off their @ss and build a set of 4-valve heads for the Buick V6 like they did for the SBC, then 1300-1500 HP would be extremely easy for Don to accomplish. Until then, comparing a hindered 2-valve cylinder head to a 4-valve cylinder head is ridiculous....
Valve Covers Crankshafts 4 Valve Heads 2 Valve Heads
[video=youtube;vRKTRLD2h8k]http://www.youtube.com/watch?v=vRKTRLD2h8k[/video]
So if I'm thinking right about this, as boost pressure is increased the theoretical choke point of the port will be at a slower speed through the port since the speed of sound through the port will now come about at a slower speed.
Another point that illustrates the need for an alcohol mixture to be up to a certain temp range before ignition, is a n/a alky engine. You just can't get enough static compression into a n/a alky engine. On top of that, a tuner will add an extraordinary amount of spark lead to increase temperatures DURING combustion.
If this is true, then for me to increase boost in hopes of drastically increasing performance with these small heads seems to be a bit silly. With each pound of boost increase, I'm compounding the resistance to port flow.
I think the better option to increasing boost at this point, would be to start adding small increases in nitrous injection throughout the pass. Not a 360 hp shot, but maybe start out with a 25 shot and work it up. Still, if traction is an issue, then increasing the hp output of the engine in any manner is silly.
KL Mallender
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Hey Donnie, for what it's worth..my "basic" math skills reguarding your engines capabilities using the minimum throat areas of a 1.85in/1.50ex puts your 224 incher at 4900-5100 rpm for peak torque, 7250-7350 rpm for peak power, yes I am sure there will be variables but this is what I see.
224 inches x 30 lbs boost x 9 to 1 cr = 600 usefull ftlbs of torque between 4500 and 7000, peak very close to 720 lbs @ 5000
From watching a few of your videos(damm impressive btw) it appears to me that it is possible your torque converter flashes on the downside of torque peak(5500+), during shifts I'll bet good money your converter is multiplying that peak torque as it is pulled back down(or tried to anyway) causing some added grief to those rear tires during those shifts.
As impressive as your car leaves, it looks "soft" compared to it's pull past the tree(which just has to be one hell of a ride btw) and appears as if the car never really get's on top of the tires from what I see, like the car is trying to keep up to the engine just never quite catching up.
My observation is that the converter is just a bit too much allowing excessive slipping.
I would like to see a tighter coupler in there before ever trying to raise the boost level(which would only compound traction issues during the spikes)
A converter that was tight enough for you to leave the line below 5000 without increasing NO2 to get her up online.
I think she has a bit more to give(Yes, I believe 7's) but the conveter in right now might very well just slip away further if boost is increased as is.
Just my 2 cents worth, hope you find that missing piece of the puzzle, 'cause it's there for you, bet you can almost taste it too.
Best of luck to you bud's,
Kevin.
224 inches x 30 lbs boost x 9 to 1 cr = 600 usefull ftlbs of torque between 4500 and 7000, peak very close to 720 lbs @ 5000
From watching a few of your videos(damm impressive btw) it appears to me that it is possible your torque converter flashes on the downside of torque peak(5500+), during shifts I'll bet good money your converter is multiplying that peak torque as it is pulled back down(or tried to anyway) causing some added grief to those rear tires during those shifts.
As impressive as your car leaves, it looks "soft" compared to it's pull past the tree(which just has to be one hell of a ride btw) and appears as if the car never really get's on top of the tires from what I see, like the car is trying to keep up to the engine just never quite catching up.
My observation is that the converter is just a bit too much allowing excessive slipping.
I would like to see a tighter coupler in there before ever trying to raise the boost level(which would only compound traction issues during the spikes)
A converter that was tight enough for you to leave the line below 5000 without increasing NO2 to get her up online.
I think she has a bit more to give(Yes, I believe 7's) but the conveter in right now might very well just slip away further if boost is increased as is.
Just my 2 cents worth, hope you find that missing piece of the puzzle, 'cause it's there for you, bet you can almost taste it too.
Best of luck to you bud's,
Kevin.
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