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

[Alky V6]

Hey Kevin, If you want ANY specs on my combination so that you can play with them, don't hesitate to ask. I'd hate for you to waste time working with an incorrect spec. BTW, I don't keep any secrets about my combination, so ask away.
There is a pinch point in the intake runner that I use to calculate the minimum diameter for the intake port. That number is 1.710".
Fuel consumption of an engine is typically greatest at peak torque. Understanding that, it is easy to look at a well dialed in fuel map to determine exactly where peak torque for the engine is. If you go to my gn page on my website, there is a screen shot of one of the more recent revisions of my fuel map for the engine. I'm sure you will agree that peak torque clearly occurs at exactly 5700 rpm.
Intake duration primarily is what sets the operating range of the engine.

 

[Alky V6]

The stall speed of my TC is tricky. At zero boost, zero nitrous, it stall just over 3,000 rpm, presently. The engine is getting tired. It has stalled to 3200 when the engine was not so tired.
The stall on the nitrous is interesting. As you can imagine, the more nitrous, or more correctly as in my case, the longer length of time the nitrous is activated, the higher the stall can be pushed. Once a certain rpm and boost level has been reached, the nitrous can be shut off and the engine will maintain a controlled rpm and boost level. When I say controlled, I mean with the help of either wastegate, BOV, fueling and timing. Sometimes a combination of any of the later. More recently, using a certain level of control from all of the later.
These days I'm shooting to level out the rpm and map for the launch to around 5500 rpm and 190 kPa MAP.
Uncontrolled, the rpm and boost can continue to climb without the nitrous and still on the transbrake to over 6200 rpm and over 220 kPa MAP. I have never let it go any higher than that for obvious durability reasons.

 

[Alky V6]

I agree with you Kevin that the TC could be tighter on the top end. I used to have a tighter TC in the car. A N/C 10". It was great on the top end, but did nothing to help me get spooled up to my satisfaction. Granted, that was back before I really got this nitrous tune dialed in.
This engine/turbo combination really likes the engine rpm to be in the 5,000s for the launch. Anything lower and the car comes off the line slowly. Much like the in car video I have of the car on YouTube. You can note by the tach in the video where the launch rpm was at, and where things start to really come alive as the tach climbs through the roll out. That problem is mainly due to the turbo match. The boost climb ramp up increases climb rate to a good tune after about 5200 rpm and 145 kPa MAP. The more rpm and map I can leave the line with, the faster the rpm and map climb rate through the initial section of the launch.
The in car video was taken when I had first installed the 91mm turbo. The N/C TC was in the car for that video.

 

[Alky V6]

Here's that video I was talking about. Notice I wasn't using the nitrous to pre-spool the turbo before the launch at the time. This was one of the first, if not the first pass, with the 91mm. The nitrous activated on transbrake release and I can't remember when it was shut down. Most likely around 145 kPa MAP.
DRW / Buick V6 Alky v3.2 20L video test - YouTube
Go to 7:12.

 

[KL Mallender]

I use minimum areas to base any 4 stroke engines opperating "range", Intake area will dictate maximum rpm before everything hits the ****ter, but it has been my experience that exhaust area always dictates the "end of all that is good", once this begins you or I could shovel in everything available and see very little in return from the crankshaft, I see the negitive "work" required go up trying to expell unburnable gasses especially during the final stages of exhaust valve closing/overlap period, offsetting any gains the intake can replenish via rpm or "boost" pressure increase.
I really do believe we "Boost Heads" have it somewhat backwards in reguards to valve sizing for optimal use, we are always using a head designed based from a naturally aspirated baseline, but it is what it is untill further notice from the turbo gods themselves.
Your 5700 rpm tq pk value is much more precise than my guesstimates, I'll wager your work on reducing back-pressure has a bearing on this during the overlap period.
I believe you will see the car improve it's performance if you can achieve a better "coupling" via converter stator change.
The car is getting a benefit of the extra torque multiplcation(slippage) right now, and if you do tighten it up I would expect it to slow down a little at the same boost levels, but will gain speed from engine torque/boost increase later, right now your car "balanced" between the two, any more boost just causes more slippage than gains per pound of boost(diminishing returns).


Kevin.

 

[Alky V6]

I use minimum areas to base any 4 stroke engines opperating "range", Intake area will dictate maximum rpm before everything hits the ****ter, but it has been my experience that exhaust area always dictates the "end of all that is good", once this begins you or I could shovel in everything available and see very little in return from the crankshaft, I see the negitive "work" required go up trying to expell unburnable gasses especially during the final stages of exhaust valve closing/overlap period, offsetting any gains the intake can replenish via rpm or "boost" pressure increase.
I really do believe we "Boost Heads" have it somewhat backwards in reguards to valve sizing for optimal use, we are always using a head designed based from a naturally aspirated baseline, but it is what it is untill further notice from the turbo gods themselves.
Your 5700 rpm tq pk value is much more precise than my guesstimates, I'll wager your work on reducing back-pressure has a bearing on this during the overlap period.
I believe you will see the car improve it's performance if you can achieve a better "coupling" via converter stator change.
The car is getting a benefit of the extra torque multiplcation(slippage) right now, and if you do tighten it up I would expect it to slow down a little at the same boost levels, but will gain speed from engine torque/boost increase later, right now your car "balanced" between the two, any more boost just causes more slippage than gains per pound of boost(diminishing returns).


Kevin.

I did try different stators with the N/C trying to loosen it up a little more for the launch, but was forced to move to a 9.5" which does great for tuning in the launch, but slips much more on the top end. Still, this 9.5" is not too bad. When shifting at a range of different shift points, the rpm falls to 6300-6400 rpm consistently. Approximately a 700-800 rpm drop.

 

[Alky V6]

Considering that the sim was not real accurate at estimating the peak HP level, it did predict peak torque to be at 5700 rpm.

 

[Alky V6]

This 9.5" does have the loosest stator in it. We started out with the loosest one they had for this configuration. There are tighter stators available for this combination.

 

[KL Mallender]

That sounds very familar to me, I can understand the frustration, but observe your cars reaction to the violence in that 5000 rpm range, it want's nothing to do with what is coming from the crankshaft in that area, it(the converter) finally has a grip on it well after torque peak(whatever the number, it has to be stupid) on the down slope of torque production and runs that for the length of the run.
Be nice(maybe not) if your engine could be harnessed from 5500 rpm out, I say "maybe not" only because of how really violent it could be to the tires if not hooked,

Kevin.

 

[Alky V6]

That sounds very familar to me, I can understand the frustration, but observe your cars reaction to the violence in that 5000 rpm range, it want's nothing to do with what is coming from the crankshaft in that area, it(the converter) finally has a grip on it well after torque peak(whatever the number, it has to be stupid) on the down slope of torque production and runs that for the length of the run.
Be nice(maybe not) if your engine could be harnessed from 5500 rpm out, I say "maybe not" only because of how really violent it could be to the tires if not hooked,

Kevin.

I'm actually doing a lot of suspension work trying to dial in the launch with the car, including trying to target a launch rpm and map level. Presently, I'm working with shock settings with a new IC setting.
I agree with your 5500 recommendation. I've been thinking about going with a tighter stator to tighten up the top end and better control the launch rpm, but I want to finish playing with the suspension settings for this configuration first. I think after I've fully explored the suspension settings, I may have a better idea of how the tighter stator will help out. You know what they say about making too many changes at one time.

 

[Alky V6]

I do have to add, that none of the vids I presently have really show as good a launch as what the car has done in the recent past. After a recent IC change the car launches a lot different. Likes to keep the nose down. After I've exhausted the available shock settings, I may end up splitting the difference between the new and old IC settings and start all over with the shock settings.

 

[baadgn]

I did try different stators with the N/C trying to loosen it up a little more for the launch, but was forced to move to a 9.5" which does great for tuning in the launch, but slips much more on the top end. Still, this 9.5" is not too bad. When shifting at a range of different shift points, the rpm falls to 6300-6400 rpm consistently. Approximately a 700-800 rpm drop.

why does it always go back to 6300-6400 Don ?

 

[Alky V6]

why does it always go back to 6300-6400 Don ?

I'm guessing it may be the true stall of the TC for my combination.

 

[Alky V6]

In the 1940s, C. F. Taylor and co-workers from MIT found a good correlation between volumetric efficiency and Mach # for several engines with conservative cam timing. The correlation showed that volumetric efficiency (and therefore power) would start to drop sharply when Mach # increased above approximately .55. However recent studies show poor correlation if intake cam duration increases significantly. The 1979 paper includes a correction for intake duration; the higher the intake duration, the lower the Mach #, and the higher the RPM for peak volumetric efficiency.

General "rules of thumb" concerning the Mach # include:

Peak volumetric efficiency should occur in the range of .3 to .5 Mach # with no tuning effects.
Volumetric efficiency drops rapidly in the range of .6-.8 Mach #.

The Mach # is calculated based on the static intake valve flow area, not the dynamic flow area which can be different due to valve train bending and tossing.

I'm hoping that some of you picked up on this tid bit of information.
Tuning effects. What's that? Is there some tuning effect that can actually move the peak volumetric efficiency point of a port to a higher Mach #? Allowing a person to get more flow out of a particular port/valve size?
Pressure pulse tuning, gentlemen. Pressure pulse tuning.

 

[cruzn57]

uh...ok

I have no idea. I am pretty sure PTE was doing his motors back then so Dan Strezo might know as he is probably the one that did the heads and built the motor. I've flowed a few M&A heads and the intake ports never flowed that well. I think the largest valve you could stick in there was 1.90 without moving the guides. I never saw an M&A flow much better than mid 220's without doing something extravagant.

these are few yrs ago, they were improved since then, but heres what was achiceved then, with no welding, no radical work,

 

[bison]

I wonder how fast others have managed to push the Buick V6 with 1.835 and 1.5" valves? How many made it into the 10s? How many made it into the 9s?

Plenty have made it into the 10's with unopened engines and plenty have been 9's with some simple clean up bowl work and a valve job. In a TSM car the iron heads (valve size not known but probably 1.83" or smaller intake and 1.5 ex) have been south of 9.50. The limitation on the iron head isnt the diameter of the valves. Its the amount of work you must do to get a decent set of springs on there and have the valvetrain work properly. On a set of Gn1 heads with chevy valves you an select a bunch of different double springs to work with and you will be covered well into the 8's with minimal modification to get a larger spring in. Also the rocker arrangement and retention is a lot better on the aftermarket heads.There would be many others going faster with iron heads if there was nothing else out there but the cost to performance gain is so much greater on an aftermarket head at that level most do the obvious. The afterarket heads have a lot more material on the intake side of the combustion chamber and dont deflect like the iron heads do wih a lot of cylinder pressure.

 

[Alky V6]

Very impressive, Lee.

 

[Alky V6]

Plenty have made it into the 10's with unopened engines and plenty have been 9's with some simple clean up bowl work and a valve job. In a TSM car the iron heads (valve size not known but probably 1.83" or smaller intake and 1.5 ex) have been south of 9.50. The limitation on the iron head isnt the diameter of the valves. Its the amount of work you must do to get a decent set of springs on there and have the valvetrain work properly. On a set of Gn1 heads with chevy valves you an select a bunch of different double springs to work with and you will be covered well into the 8's with minimal modification to get a larger spring in. Also the rocker arrangement and retention is a lot better on the aftermarket heads.There would be many others going faster with iron heads if there was nothing else out there but the cost to performance gain is so much greater on an aftermarket head at that level most do the obvious. The afterarket heads have a lot more material on the intake side of the combustion chamber and dont deflect like the iron heads do wih a lot of cylinder pressure.

All very good points, bison.

 

[Alky V6]

I should add for those that believe the alcohol fuel is the reason for the 8s. The engine analyzer software does take into account the type of fuel I'm using, and the temperature drop associated with the particular a/f ratio chosen.
For a blown alcohol application, many alky tuners believe that the best intake air temperature to have after air compression from the blower or turbo is around 155-165 degrees F. Many alcohol tuners believe that to be the target intake air temperature to shoot for to attain best power out of the air/fuel charge. The sim and real world datalogs have shown my intake air temps to be much, much cooler. So if one is to believe popular opinion about the optimum intake air temperature for a blown alcohol application, I am way too far to the cool side to pull max power out of the a/f charge. That's probably why I feel my car runs harder at the finish of a run. The intake has had time to heat soak and bring intake air temps up to where they need to be for an alcohol application.
I should probably pull the intercooler off the car. Although, with higher boost numbers, it may come in handy.

 

[Alky V6]

Next, I'm going to post up the datalog of the 8.76 run the car made at Firebird. It is the same run that is in my sig. This will give us a chance to dissect it a little.