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

[Mike E]

Donnie, you seem to be fishing for a certain answer. I have a feeling you want to hear that it's a good combination of parts that got you to those times. While it is a good combination of parts, it's a weird and complicated combination of parts. Nitrous, Alcohol, miles of plumbing and months of tuning to get a turbo that big to spool is not the prefered way to get to the ET your at. You could have put some stroke in your motor and an 76mm turbo and run the same times on alcohol with no help to spool it. The valve sizes are practically irrelevant. Boost overcomes any restriction in your intake tract. Your boost numbers are relatively low, but with alcohol you don't need to move the same amount of air as a gas powered motor to make the same power.

You certainly think outside the box and are critical of everything. That's good and eventually you'll run across something new that will benefit everyone. If no-one went outside the box, we would never see any advancements.

In the previous thread about camshafts, you talked about how you benefit from overlap. The reason you can do that while others can't is because of the alcohol. You'll never get as much backpressure as a gas motor because alcohol doesn't have the exhaust heat that gas does. It's also a big reason why you have to spray a 400 shot to spool a 91mm turbo.

 

[turbobuick]

I havent read every thread but seriously a 400 shot? That much NOS at a low RPM cant possibly be good for the rods if that is what you are seriously doing.

 

[Mike E]

post 84 in this thread. Maybe he was joking. http://www.turbobuick.com/forums/engine-tech/362375-928-hp-chasis-dyno-today-thanks-otto-3.html

 

[Dusty Bradford]

Back pressure and alcohol.

You use a turbo way oversized to get the back pressure less than 1:1 along with highly oxygenated fuel which greatly increases hp in a turbo engine.

 

[Alky V6]

Donnie, I have never knocked you or your combo over the years and have tried to give you advice based on my own past experience that I though would be helpful. I can appreciate that you beat to a different drum as I'm not one to follow the crowd either and I also like to think outside the box. You my friend are pretty far outside the box and there is no SIMPLE answer for your questions.

That being said lets look at the issue. You feel the heads are holding you back? What would you see if this where the case? You keep talking boost numbers but to me your intake boost pressure is probably one of the most irrelevant numbers to be concerned about and is really the only metric you have given us. What is the system doing? What do the turbo outlet temps look like? What does the exhaust back pressure look like? What does your fuel consumption look like at higher RPM? You say you shift at 7400 and max at 7800 but is the motor making power there? Where is peak TQ and peak HP and how are you making that determination? Do you have any accelerometer data? With this combo what is your target trap speed and rpm and what are your ultimate ET goals. Is the car geared correctly for these goals and is the turbo properly matched for the power levels you are trying to accomplish? What does the compressor map look like and where are you as far as the pressure ratio is concerned?

You keep talking about the heads and I think most who look at your combo would agree there are multiple other issues we would dive into first before the heads. IMO Cliff's right at the point you are at a 2.10 valve wouldn't make a difference. BTW the "opinions" I gave on header design where based on experience and data I have gathered on my car not just opinion. I don't know for sure what was done to Bob Peterson's M&A heads but I would bet they weren't anything exciting and nothing more than a nicely ported set.

To answer your questions in order.
1) Progressively less increase in performance as boost was incrementally cranked up. The intake port and valve would become the choke point.
2) Ask a specific question and I'll do my best to give you an accurate answer.
3) 1200-1300 degrees F.
4) EBP to IBP ratio is .85-.95:1.
5) BSFC 1.18. Very conservative (lean side) for an alcohol burner.
6) The power is pretty flat from 5700-7800. I choose to shift at 7400 to save on the engine. ET doesn't change when using shift points between 7200-7800.
7) Peak torque is, without question 5700 rpm. The fuel table clearly points that out. This also matches what the sim has suggested. Peak HP depends on the boost level being used. Anywhere from 6800-7100 rpm.
8) No accelerometer data.
9) Ultimate ET goal is to break the chassis cert. 8.50. Not far from that now. I'll post the datalog of the 8.76 pass I did with the car. When you see the traces, I'm sure you'll come to the same conclusion that the car will beat the chassis cert as the car sits now.
10) The cars gearing is a little on the low side. Could use a higher gearset.
11) I feel the turbo is matched perfectly for the top end charge.
12) I've posted the compressor map before. At max airflow as the engine sits today with the small heads, I'm just a pinch left of being smack dab in the middle of the highest efficiency island of the compressor map.

 

[Alky V6]

You keep talking about the heads and I think most who look at your combo would agree there are multiple other issues we would dive into first before the heads. IMO Cliff's right at the point you are at a 2.10 valve wouldn't make a difference. BTW the "opinions" I gave on header design where based on experience and data I have gathered on my car not just opinion. I don't know for sure what was done to Bob Peterson's M&A heads but I would bet they weren't anything exciting and nothing more than a nicely ported set.

I agree. A larger valve by itself with no other changes would not make a difference.

Where it comes to using long tube headers, with the incorrect combination to work with the headers, they would be a complete waste of time.
If one were to configure their setup to work with short tube headers, then just simply slap on a set of long tube headers to see what would happen, I would expect no success.

 

[Alky V6]

I sense a lil sarcasm from Donnie

No sarcasm, really. I'm very curious as to how I'm in the 8s with a small valved head, small cubes, and very, very little others are. What is making the difference? Especially with all these odd ball specs working against me.

 

[Alky V6]

My friend toms car went 9.3 @ 148 in bg with m&A's, old design 88. This was on about 23 psi and e85. Car is 3510lbs, no exotic parts. The heads are out of the box with a $500 port job. Unfortunately a piston broke (not sure why yet) and cut the quest for 8's short. It will be back together possibly this month.....if not it will be in the spring (local track closes end of this month.)

My heads are also a first generation production run. And I'm not just in the 8s, I'm deep.

 

[Alky V6]

Donnie, you seem to be fishing for a certain answer. I have a feeling you want to hear that it's a good combination of parts that got you to those times. While it is a good combination of parts, it's a weird and complicated combination of parts. Nitrous, Alcohol, miles of plumbing and months of tuning to get a turbo that big to spool is not the prefered way to get to the ET your at. You could have put some stroke in your motor and an 76mm turbo and run the same times on alcohol with no help to spool it. The valve sizes are practically irrelevant. Boost overcomes any restriction in your intake tract. Your boost numbers are relatively low, but with alcohol you don't need to move the same amount of air as a gas powered motor to make the same power.

You certainly think outside the box and are critical of everything. That's good and eventually you'll run across something new that will benefit everyone. If no-one went outside the box, we would never see any advancements.

In the previous thread about camshafts, you talked about how you benefit from overlap. The reason you can do that while others can't is because of the alcohol. You'll never get as much backpressure as a gas motor because alcohol doesn't have the exhaust heat that gas does. It's also a big reason why you have to spray a 400 shot to spool a 91mm turbo.

I have to disagree. Boost is very relevant. Anyone that turbocharges an engine understands what more boost gets you. And what less boost gets you. It's no different with my engine.

I'm really not interested in going over the multitudes of other combinations that could net me the same results. What I am interested in is why my strange combination is able to do 8s.

Valve size is very relevant, and boost does not overcome all. There is a certain velocity through the port where flow will choke. The mach number. That is simple physics and no one is immune to it. The smaller the valve or port, the sooner you reach that mach number. This is why flow numbers are important with head selection. When you can start out with a better flow number, it's a good sign that you won't as easily reach that restrictive mach number.

Incorrect. An alcohol engine still needs air just like any other internal combustion engine. In fact, because an alcohol engine requires so much more fuel which displaces the intake air, larger ports are preferred over small ports with an alcohol burning engine. Study the chemistry of burning alcohol in an internal combustion engine more carefully.

What alcohol lacks in exhaust heat, it makes up with higher volumes of 'by products of combustion' (mass).

Alcohol will create exhaust back pressure. I've already proven that when I was running the T76. The back pressure ratio was 1.5-1.6:1 with a Q trim, .96 a/r housing. That is not out of the realm of what a gasoline engine would do.

 

[Alky V6]

I havent read every thread but seriously a 400 shot? That much NOS at a low RPM cant possibly be good for the rods if that is what you are seriously doing.

I would have to dedicate a wholenother thread to explain why I can get away with a 400 shot. It has to do with the whole combination.

 

[Alky V6]

Back pressure and alcohol.

You use a turbo way oversized to get the back pressure less than 1:1 along with highly oxygenated fuel which greatly increases hp in a turbo engine.

You can get more out of an alcohol engine than a gasoline engine "IF" the engine is setup to take advantage of the alcohol fuel. We already discussed that an alcohol engine needs larger ports to compensate for the higher volume of fuel that must be ingested without compromising air intake volume. We know that a typical blown alcohol engine will use 10-12:1 CR to take advantage of the alcohol fuel. I'm running 9.25:1. The only way I can really start seeing an advantage from the fuel would be to run monster boost numbers. Like I said before, 40-45 psi boost is where the fuel would really shine with my engine.

 

[Alky V6]

Back pressure and alcohol.

You use a turbo way oversized to get the back pressure less than 1:1 along with highly oxygenated fuel which greatly increases hp in a turbo engine.

Back pressure. How would a 1:1 or better ratio actually help? I thought everyone needed gobs of back pressure just to make the turbo work.

 

[Alky V6]

post 84 in this thread. Maybe he was joking. http://www.turbobuick.com/forums/engine-tech/362375-928-hp-chasis-dyno-today-thanks-otto-3.html

What do you think? Was I? How does any of that make my car do 8s with small 1.835" valved heads?

 

[Dusty Bradford]

Back pressure. How would a 1:1 or better ratio actually help? I thought everyone needed gobs of back pressure just to make the turbo work.

I'm sure your being sarcastic again. You know why twins make more power than a single when the same 30# of boost is generated on the intake side.

You bring cubes in the equation but cubes don't really matter on a turbo engine. You lack low end torque due to the short stroke, large cam and large turbo. The nitrous makes up for all of this. The reason your running as fast as you are with the heads you have is solely due to the back pressure #. I bet I could do the same with a set of properly sized twins and log manifolds.

 

[Dusty Bradford]

Your heads flow about like a ported iron head. Look at what John Plog ran. He can run 9 teens on an iron head with a 70mm turbo, factory style headers and gas at 130# heavier than you. Just swapping his car to twins would easily put him in the 8's on an iron head.

 

[six is enough]

I run 1.94 intake and 1.60 exhaust. Have run time in sig with a 4788 turbo at 30 psi. Use nitrous to spool also. Car only weighs 3200 pounds. Would like to talk to you sometime.

 

[Alky V6]

I'm sure your being sarcastic again. You know why twins make more power than a single when the same 30# of boost is generated on the intake side.

You bring cubes in the equation but cubes don't really matter on a turbo engine. You lack low end torque due to the short stroke, large cam and large turbo. The nitrous makes up for all of this. The reason your running as fast as you are with the heads you have is solely due to the back pressure #. I bet I could do the same with a set of properly sized twins and log manifolds.

Cubes always matters. Always.
The nitrous is used before the car leaves the line. It is shut down before the car leaves the line. Nitrous has nothing to do with the car from the point where the car leaves the line all the way to the finish.
If low back pressure were the answer, then you would surely see everyone putting monster turbine sections on their turbos and doing 8s with small heads. That doesn't seem to be the case, though.

 

[Alky V6]

Your heads flow about like a ported iron head. Look at what John Plog ran. He can run 9 teens on an iron head with a 70mm turbo, factory style headers and gas at 130# heavier than you. Just swapping his car to twins would easily put him in the 8's on an iron head.

Yes. I did 9.10s when the old T76 was on the car along with a 1.5-1.6:1 exh. to int. pressure ratio, with a larger cam and long tube headers.
Back pressure sure does seem to be part of the answer. But is back pressure alone the answer? What sort of things does a low exhaust back pressure allow to happen? Could one simply slap a monster turbine housing on their small cammed and small headed car and go out and do 8s? If that were truly the case, why aren't there more simple builds doing 8s?

 

[Alky V6]

I run 1.94 intake and 1.60 exhaust. Have run time in sig with a 4788 turbo at 30 psi. Use nitrous to spool also. Car only weighs 3200 pounds. Would like to talk to you sometime.

Wow! I like that 60'. Big tire car?
Anyone is welcome to call me at the shop, anytime. Tell Wayne you want to talk to Don about Buicks.

 

[Alky V6]

The intangible specifications

I think now we are beginning to get into the intangible properties different combinations can have. We've looked at the parts, and if one were to just look at the parts alone, they might see a miss match of components that, according to popular opinion, should not work at all.
What are the intangible properties? How are the intangible properties allowing my small valved engine to do 8s? Low back pressure in itself does not create horsepower. More air and fuel must be burned to creat more power.