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

[Blazer406]

180-190 on the seat. The spring rate is 620 lb/in.
You're right about the spring pressure. Even the sim is showing that I'm on the edge of exhaust valve float at 31 psi.

I'd try alot more spring than that......

If my theory is correct.... you put some big springs in there and the power wouldn't be showing to tail off near as much as you increase boost.

 

[Alky V6]

Does the sim take into account the backpressure?

You may not realize how much effect the backpressure has on hp.

The new line of pro-mod turbo's from precision focus on this, as well as some compressor improvements.

A good friend of mine has some nice data from a 94mm with the old design G-trim to the new HP series. The car picked up .2 and 10mph in the 1/8 from a turbo change alone. It's running faster than cars with 106's were running just 5 years ago.

Since you seem to think it's not backpressure helping the combo make this power with your heads, what do you think it is?

The sim does allow changes to the turbine side so that you can adjust the EBP to IBP ratio. It does help, but not at as drastic enough of a change to make up for that much hp difference between the sim and real world that I was seeing. Believe me, I tried all kinds of turbo parameters first before I was forced to change the head cfm numbers. In fact, I resisted for a long time changing the head numbers. I hit every other grey area parameter I could find, first. Adjusting up and down, then moving to another grey area and playing with it. I left the head parameters for the very last. The head cfm is what finally brought the whole sim into focus.

I never stated that exhaust back pressure wasn't it. It is only part of the answer. Remember the question I asked awhile back? What is it that low exhaust back pressure allows to happen? Why did fuel consumption increase in the EBP case you brought up?
Low exhaust back pressure will decrease mechanical pumping losses, but not hundreds of hp worth. Maybe, if you're talking about an extreme pressure ratio change. But, even that would depend on how the rest of the combination dealt with the new low exhaust back pressure.

 

[Alky V6]

I'd try alot more spring than that......

If my theory is correct.... you put some big springs in there and the power wouldn't be showing to tail off near as much as you increase boost.

Very good point. That may be worth a try with the new heads.

 

[Alky V6]

There are things that low exhaust back pressure encourage to happen. Particularly if you attain the holy grail. CROSSOVER. An exhaust back pressure that is lower than the intake boost pressure. What are those things and how can you change other parameters of the engine to take advantage of those things?
Like I stated earlier, low exhaust back pressure by itself does not create hp, except in the case of pumping losses, but that is small compared to others things that can be changed to take advantage of crossover.

 

[Blazer406]

You are converting exhaust energy to create boost. In theory... you could generate alot of power with a huge turbine side that would impart enough torque to spin that compressor wheel fast enough to get what you are after, but why? It is going to be a dog to get it up there. Extremely inefficient until it gets spinning in it's RPM sweet spot......

It is what you are doing.... big turbo... big hot side.... Nitrous to spool it up......

Like I said... put some valve springs on it and cut it up..... if it won't stay hooked.... spend some $$ and R&D on the chassis..... there are guys with 275's running 6's.....

 

[Dusty Bradford]

You can change the cam profile to take advantage of the low ebp but that isn't hundreds of hp. Maybe 50hp at the most.

There are so many dynamics inside an engine that I feel even a simulator can't fully duplicate.

 

[Alky V6]

You are converting exhaust energy to create boost. In theory... you could generate alot of power with a huge turbine side that would impart enough torque to spin that compressor wheel fast enough to get what you are after, but why? It is going to be a dog to get it up there. Extremely inefficient until it gets spinning in it's RPM sweet spot......

It is what you are doing.... big turbo... big hot side.... Nitrous to spool it up......

Like I said... put some valve springs on it and cut it up..... if it won't stay hooked.... spend some $$ and R&D on the chassis..... there are guys with 275's running 6's.....

I'm sure it's the track that's giving me the traction problems. There's a known issue with the track. I've discussed it on this board before. I'll need to take it to a different track to really flog this sucker.

 

[Alky V6]

You can change the cam profile to take advantage of the low ebp but that isn't hundreds of hp. Maybe 50hp at the most.

There are so many dynamics inside an engine that I feel even a simulator can't fully duplicate.

I tend to agree with you on that.

 

[Alky V6]

Well, I guess we still don't know why this thing is doing 8s with 1.835" and 1.50" valves. I stumbled onto something unique. Just wish I knew what it is.

 

[Alky V6]

Thinking back when I was working with the sim to come up with something that would do the best job of making up for the shortcomings of the heads, it was, of course, the camshaft specifications. Relying on duration and lift to maximize area under the curve, and overlap in hopes of doing the best job of purging the chamber of residual exhaust for improved VE.
The exhaust manifold specs gave the overlap spec of the camshaft the best shot at purging the chamber using pulse tuning to improve VE.
The turbine side of the turbo gave me low exhaust back pressure which allowed me to achieve crossover in the chamber which only helped the exhaust manifolding to make the best of the overlap spec of the camshaft, improving VE.
The size of the compressor side of the turbo allowed it to run at highest efficiency during max load, improving VE.
The alcohol fuel helped cool the intake charge, making for a denser charge, improving VE.
The nitrous let me get away with all the above specifications by providing the best sort of ALS.
The short stroke slowed intake port velocity which, along with the intake duration, allowed me to obtain a higher engine rpm from the heads and have good power clear up to redline.

I guess in the end it wasn't just one thing that put these small valved heads deep in the 8s.
It was everything.

 

[KL Mallender]

I'm sorry if my reply is late/un-needed/un-wanted(most probable), but if I win this guessing contest, do I win a cookie?
With all due repects to Don and others for their efforts, and those that might not like what I have to say but, some/many of you guy's are at least 7, more probably 10 years behind 2011 knowledge and most likely to remain that way as I see it, this group has done little in it's ability to change/adapt/improve with age.
You have reason to hate me now, mark the calender of date.

Kevin.

 

[Alky V6]

I'm sorry if my reply is late/un-needed/un-wanted(most probable), but if I win this guessing contest, do I win a cookie?
With all due repects to Don and others for their efforts, and those that might not like what I have to say but, some/many of you guy's are at least 7, more probably 10 years behind 2011 knowledge and most likely to remain that way as I see it, this group has done little in it's ability to change/adapt/improve with age.
You have reason to hate me now, mark the calender of date.

Kevin.

Please, Kevin. Enlighten us with your knowledge. What is the obvious, outdated magic bullet that has allowed my combination to achieve 8s with only 1.835" and 1.50" valves with moderate boost, small cubes and a heavy car, where so many others, over the years, couldn't? I am always interested in the learned opinions of others.

 

[Alky V6]

A superior ALS in action. Smooth, quick, and without massive pressure spikes to shock load the machinery.
Updating the Nitrous/Methanol ALS Tune-up. Large T6 91mm Turbo! - YouTube
One thousand one one.

 

[bison]

How would you know? Have you ever driven a 1000+ bhp, nitrous assisted, turbocharged car on the street?
Sounds like it would be a bunch load of fun to me.

No
No but I ran an 800+hp nitrous assisted turbocharged car on the street and it was more than a handful. It was only a 66mm compressor with a 3 bolt ex housing. Who would have thought?

 

[KL Mallender]

Please, Kevin. Enlighten us with your knowledge. What is the obvious, outdated magic bullet that has allowed my combination to achieve 8s with only 1.835" and 1.50" valves with moderate boost, small cubes and a heavy car, where so many others, over the years, couldn't? I am always interested in the learned opinions of others.

Don, It was not my intention to discount/demean your acheivements with "Your" car, you have spent uncountable hours trying to refine it in areas that most(if not the majority) will never truely grasp, for that alone I send my utmost in respect to you in trying to pass along your knowledge to others here(not just the dripping fangs type) to find of value, if just a few pick up on what you wrote upon these walls, fellow members would not be running over some of their hard earned money/time after time. I have no magic "bullets" in my arsenal, but I pay attention to certain things many consider irrelevent from their view, I'm am not a believer in so called bad "parts", I do believe "we" knuckle draggers bring most if not all our mechanical failures upon ourselves, sometimes accidently because we didn't/don't know any better, the rest just blow **** up without a care/concern in the world and call it a day.
I know you to be a "Thinker", well, so are others in this arena of power production, you've seen/touched/felt things which caught your interest on solving a puzzle and I'll bet you saw the same thing long before a turbo Buick entered your life, but this vicious bitch has you busy just keeping up with the ass kissing, and you know what I'm referring to, well, at least I have a clue anyway. If Don won't/can't admit most of what I just wrote to be true, I'll pass on posting it here, 'cause it just won't find a home anywhere.

Kevin.

 

[Mike E]

... What is the obvious, outdated magic bullet that has allowed my combination to achieve 8s with only 1.835" and 1.50" valves with moderate boost, small cubes and a heavy car, where so many others, over the years, couldn't? ....

Why do you assume you have achieved some impossible feat by running 8.8x with a 1.835/1.5 valves and a small motor with little boost? You think others couldn't, who actually tried it as a goal and failed. Thats a very specific goal to accomplish and your unlikely to ever find anyone else to even want to try it.

Your engine obviously uses air and fuel efficiently. If that was your goal, you accomplished it.

Most others including myself are not extremely impressed because we see it as tripping over dollars to pick up dimes. Your chasing after less than 50hp from effeciency while you could pick up multiple times that with the properly sized smaller turbo.

 

[Mike E]

You should buy an engine dyno. You could quantify all your theories very quickly. The ammount of data you can get from a good engine dyno session would keep someone like you with such a critical mind busy for days or weeks. It can be a very impressive tool.

I used to worked for a very smart guy with an engine dyno that specialized in turbo and blower stuff. He tought me a lot about the value of proper test procedures and accurate test data. You can learn so much more than just the values of the sensors you datalog.

 

[Alky V6]

Why do you assume you have achieved some impossible feat by running 8.8x with a 1.835/1.5 valves and a small motor with little boost? You think others couldn't, who actually tried it as a goal and failed. Thats a very specific goal to accomplish and your unlikely to ever find anyone else to even want to try it.

Your engine obviously uses air and fuel efficiently. If that was your goal, you accomplisohed it.

Most others including myself are not extremely impressed because we see it as tripping over dollars to pick up dimes. Your chasing after less than 50hp from effeciency while you could pick up multiple times that with the properly sized smaller turbo.

I don't expect everyone to be amazed by this trivial feat I've accomplished. I'm sure it impresses some who are working hard to just do as well with much more engine, much more head, and even with a much more properly matched turbo.

I set goals for myself. It is I who I try to impress the most by reaching the goals I set for myself. I will say, I have impressed myself.

 

[Alky V6]

Don, It was not my intention to discount/demean your acheivements with "Your" car, you have spent uncountable hours trying to refine it in areas that most(if not the majority) will never truely grasp, for that alone I send my utmost in respect to you in trying to pass along your knowledge to others here(not just the dripping fangs type) to find of value, if just a few pick up on what you wrote upon these walls, fellow members would not be running over some of their hard earned money/time after time. I have no magic "bullets" in my arsenal, but I pay attention to certain things many consider irrelevent from their view, I'm am not a believer in so called bad "parts", I do believe "we" knuckle draggers bring most if not all our mechanical failures upon ourselves, sometimes accidently because we didn't/don't know any better, the rest just blow **** up without a care/concern in the world and call it a day.
I know you to be a "Thinker", well, so are others in this arena of power production, you've seen/touched/felt things which caught your interest on solving a puzzle and I'll bet you saw the same thing long before a turbo Buick entered your life, but this vicious bitch has you busy just keeping up with the ass kissing, and you know what I'm referring to, well, at least I have a clue anyway. If Don won't/can't admit most of what I just wrote to be true, I'll pass on posting it here, 'cause it just won't find a home anywhere.

Kevin.

Kevin, you're more than welcome to say whatever you feel. No problem here.

 

[Alky V6]

You should buy an engine dyno. You could quantify all your theories very quickly. The ammount of data you can get from a good engine dyno session would keep someone like you with such a critical mind busy for days or weeks. It can be a very impressive tool.

I used to worked for a very smart guy with an engine dyno that specialized in turbo and blower stuff. He tought me a lot about the value of proper test procedures and accurate test data. You can learn so much more than just the values of the sensors you datalog.

If I had the dough for one, I would be married to it.