Picking a New Full Race Stall Speed

[Dusty Bradford]

, I told you that you needed a TC, which I already knew, but wasn't ready to choose specs for yet.

When you say this, are you talking about telling the converter company that you want X amount of stall or that your going to spec a converter out yourself by choosing core design, size, fin angle, stator design???

No one including me would be able to get right on the money with a combination such as yours. It's going to take some testing to get something to work for you no matter which company you go with.

 

[BadAssGN]

No one including me would be able to get right on the money with a combination such as yours. It's going to take some testing to get something to work for you no matter which company you go with.

And this is why Don wanted the tune where he is happy so the data he could provide would be accurate.


Sounds like you guys are on the same page to me.

 

[Alky V6]

I would like to answer here:biggrin:

Yes, by know you should know pretty close what you need... We called up Dusty and gave him the specs and he was very close. Only did we change after making a pretty big difference...

I don't think people are trying to insult you... They are trying to help...

I don't see how you can zero in on a particular setup until you know how the new converter is going to react to the combo...

I also agree completely with this statement.
If a TC tech were to happen to supply a TC for my unique combination that worked as hoped on the first attempt, it would show that the TC tech had a very unique insight into the combination. I would not expect that to be the case. I'm sure a guess will have to be tried first with a known TC value, then after having some data from that attempt, the proper TC can be dialed in from there.

 

[Alky V6]

Don,

I read this and it raised an interesting point. How can the Torque converter specialist trust that person doing the finalized tune up has done it correctly? The same can be said on his part.

You're right. If someone is sloppy with his tuneup and has data that will backup that tuneup, then the TC tech should be able to match a TC to that data. Will it be a perfect match for that tuneup? It's possible. Is it a perfect match for the potential of that engine if the tune were optimized? Most likely not, but should be close enough to work for a person that would except a sloppy tune.

 

[Alky V6]

I would make my best educated guess, so I wouldn't have to completly retune (engine and chasis) twice. Dusty gives a free re-stall and his initial setup is going to be much closer than what you currently have. Since you're on a budget, instead of buying a convertor, why not throw the 76 back in and get that maximized. If it's a 42-76 you should be able to run mid-low 8's. I probably missed this, but what is your current ET goal?

I gained 10 mph in the quarter from the change to the 91mm right off the bat. I don't think I'll go back to the T76.

 

[Alky V6]

People were declaring your stall was wrong from the beginning because it's so far off. Anyone with any sort of experience trying to get a larger turbo spooled with a small engine can tell you it was wrong. The final tune will chage with a converter that loads the engine differently.

Yes. It was pretty obvious to me too.
The final tune will change, but not much.

 

[Alky V6]

That's easy. You trust what your converter man sends you based on their experience. In your case, it's not the performance potential, it's about the limitations you have to overcome because of the combination.

Nitrous and/or variable stall will always be a must for your combination and I know your well aware of that.

As I hope you've picked up by now, nitrous was always going to be part of the mix. The combination was based on that from the beginning.

 

[Alky V6]

When you say this, are you talking about telling the converter company that you want X amount of stall or that your going to spec a converter out yourself by choosing core design, size, fin angle, stator design???

No one including me would be able to get right on the money with a combination such as yours. It's going to take some testing to get something to work for you no matter which company you go with.

I completely understand that Dusty. I know a little bit more about matching a TC to a unique combination than people obviously think.

I don't pretend to know enough about matching individual TC components to come up with a desired result. That takes an immense amount of experience. What I do know is that a TC tech's job is much easier if you can supply him with good performance data, and hp and torque curves that are as close to the expected performance as possible.

 

[Otto J]

I gained 10 mph in the quarter from the change to the 91mm right off the bat. I don't think I'll go back to the T76.

BUT you should have been able to run about 6 MPH or more faster with your 76 so somewhere along the way your combo was NOT optimized.
if you have now gone 154 - 10 that means you ONLY went 144 with a T76 in a lightweight car.

 

[Alky V6]

And this is why Don wanted the tune where he is happy so the data he could provide would be accurate.


Sounds like you guys are on the same page to me.

You hit the nail right square on the head. Good to see someone is understanding this.

 

[Alky V6]

BUT you should have been able to run about 6 MPH or more faster with your 76 so somewhere along the way your combo was NOT optimized.
if you have now gone 154 - 10 that means you ONLY went 144 with a T76 in a lightweight car.

Mmm. I see your point. I was running the smaller 28" tires with the T76. That could be the difference.

 

[Otto J]

Mmm. I see your point. I was running the smaller 28" tires with the T76. That could be the difference.

If you were running the 4.10 gears back then,thats one place I would lay the blame.
What RPM do you shift and plan to cross the line at?

 

[HighPSI]

I gained 10 mph in the quarter from the change to the 91mm right off the bat. I don't think I'll go back to the T76.

Once again, what is your ET Goal? MPH doesn't win races. Did you take the same approach (maximizing the tune, etc...) before swapping turbos?

 

[Alky V6]

If you were running the 4.10 gears back then,thats one place I would lay the blame.
What RPM do you shift and plan to cross the line at?

The shift point is 7250 with the rpm across the finish line as high as 7800 rpm.

 

[Alky V6]

Once again, what is your ET Goal? MPH doesn't win races. Did you take the same approach (maximizing the tune, etc...) before swapping turbos?

The ET goal is 8.50 with a mph of around 158. The chassis is not certified for anything faster.
The tune with the T76 was optimized. The chassis was not.

 

[Otto J]

The shift point is 7250 with the rpm across the finish line as high as 7800 rpm.

If you are only at 154 at 7800 RPM I personally would take the rear gear back to a 3.50. I would say that alone would bumo your MPH up.
At 7800 most turbo cars are in the mid to high 160 range.
I figure once you get your convertor sorted out you will find this,
as far as 60 fts with the less gear,I have seen 1.2X 60fts on Buicks V6
cars with a 3.23 gear

 

[Alky V6]

If you are only at 154 at 7800 RPM I personally would take the rear gear back to a 3.50. I would say that alone would bumo your MPH up.
At 7800 most turbo cars are in the mid to high 160 range.
I figure once you get your convertor sorted out you will find this,
as far as 60 fts with the less gear,I have seen 1.2X 60fts on Buicks V6
cars with a 3.23 gear

I'm sorry. I should have explained better. 7800 is the redline for the engine, but the 154 was performed with 7530 rpm across the finish line. With the T76 and the 28" tires, the 145 mph was performed with over 7800 rpm across the finish line with the 4.10 gearset.

I was thinking about a higher rearend ratio, but I want to see how the new TC affects things first. The rearend was ordered with a 3.73 gearset, and that gearset is sitting in a box in the shop. Whether I try the gearset change or not will depend on how well the off-the-line performance increases with the new TC. If I end up with more than enough power for the launch, I'll use the higher gearset to tame it down.

Let's not forget this is a 3.06" stroke small cube V6. I really don't think it will end up pulling a 3.23 gear, with the 29.5 tire, anyway.

 

[S2V6RACER]

The ET goal is 8.50 with a mph of around 158. The chassis is not certified for anything faster.
The tune with the T76 was optimized. The chassis was not.

I was under the impression you are building your combo the way you were to obtain efficiency numbers you desired with the hopes of making more HP/CI than all of us with cookie cutter combos? If I was wrong then why didn't you choose a more raceable combo to run 8.50's at 158?

 

[Alky V6]

I was under the impression you are building your combo the way you were to obtain efficiency numbers you desired with the hopes of making more HP/CI than all of us with cookie cutter combos? If I was wrong then why didn't you choose a more raceable combo to run 8.50's at 158?

I've explained this before in 'the novel thread', but I'll go ahead and try to put down a short version.

The intent of this project was to build a BUICK Stage I V6 that was durable and efficient, and would allow me to explore the burning of 100% methanol fuel and the use of nitrous to spool a turbo that would be sized in combination with the nitrous, thereby allowing less compromise with the turbo sizing and spooling problem associated with large turbo to small engine combinations.
This combination was never intended to be 'competitive', but to just be a platform for me to experiment with the methanol fuel, the nitrous, and test ideas (turbo cam design, intake and exhaust manifolding) for creating efficient turbo engine operation.
This started out as my personal science experiment. It was never intended to be a project to show others that this combination could compete with, or out do any other combination being used out there in the Buick community. If you got the idea that I was trying to show up someone with this project, then you got that idea through some rumor that might have been floating around and started by someone else. If some are getting worried that it may produce more hp/cid than some more common combinations, then that's just a result from how this project has progressed and it wasn't my intent to compete on that arena. Heck, this engine is still running 1.835" int/1.5" exh valves. This combination has surpassed my wildest expectations a very long time ago.

The original planned HP level for this project was 650 HP, and maybe, just maybe, break into the tens!!! The engine kept wanting more fuel and air, and as I fed that to it, the thing grew into the monster it is today. And, it's still growing. The only thing holding it back now is chassis and fuel supply. The fuel supply system is maxed out and limiting my boost level. I'm presently running around 27-28 psi boost with an engine that's setup for 40-45 psi boost. Even so, I feel this combination will eventually max out at 1230 hp due to head flow restriction. I've calculated that it's presently at around 1130 hp. A far cry from my original expectation of 650 hp.

 

[Otto J]

I've explained this before in 'the novel thread', but I'll go ahead and try to put down a short version.

The intent of this project was to build a BUICK Stage I V6 that was durable and efficient, and would allow me to explore the burning of 100% methanol fuel and the use of nitrous to spool a turbo that would be sized in combination with the nitrous, thereby allowing less compromise with the turbo sizing and spooling problem associated with large turbo to small engine combinations.
This combination was never intended to be 'competitive', but to just be a platform for me to experiment with the methanol fuel, the nitrous, and test ideas (turbo cam design, intake and exhaust manifolding) for creating efficient turbo engine operation.
This started out as my personal science experiment. It was never intended to be a project to show others that this combination could compete with, or out do any other combination being used out there in the Buick community. If you got the idea that I was trying to show up someone with this project, then you got that idea through some rumor that might have been floating around and started by someone else. If some are getting worried that it may produce more hp/cid than some more common combinations, then that's just a result from how this project has progressed and it wasn't my intent to compete on that arena. Heck, this engine is still running 1.835" int/1.5" exh valves. This combination has surpassed my wildest expectations a very long time ago.

The original planned HP level for this project was 650 HP, and maybe, just maybe, break into the tens!!! The engine kept wanting more fuel and air, and as I fed that to it, the thing grew into the monster it is today. And, it's still growing. The only thing holding it back now is chassis and fuel supply. The fuel supply system is maxed out and limiting my boost level. I'm presently running around 27-28 psi boost with an engine that's setup for 40-45 psi boost. Even so, I feel this combination will eventually max out at 1230 hp due to head flow restriction. I've calculated that it's presently at around 1130 hp. A far cry from my original expectation of 650 hp.

1130HP at 154MPH weighing i think you said 3100? I do not think its that much.