Forced Induction's FI91X report!

[six shooter]

If anyone would like to see the detail line at any other point besides the ones I've already posted, let me know and I'll get it posted for you.

Can you post a current fuel map and narrate that for us? I am still digesting the "wall" concept.

 

[Alky V6]

At this frame the rpm is at the top of first gear. The shift to second has just been made. The MAP is just above the boost controller set level (254kPa).
The spring package in the wastegate is one level too firm. That can be seen by how far the boost spikes before the wastegate is able to bring the boost back.
MAT just starts to rise.

Right after this detail line you can see where the rpm just slightly starts to drop due to the shift to second, then the tires break loose. In the MAP and TPS views you can see that I was busy trying to gain back traction. Look at how far I came off the throttle a few times. Even after coming off the throttle that much, the turbo was able to come right back with boost when I opened her back up. The boost followed the throttle very well. Some would have thought that with having to get off the throttle that much with the large turbo, I would have lost the spool up, ruining the chance of the boost being able to recover in a reasonable time. That is not the case with this setup.

Another interesting thing to note in this frame. Even with the throttle and map dropping to try to regain traction, note the rpm. It's as if the engine is saying, "Skrew you! I'm going to the finish line!"

 

[Alky V6]

Can you post a current fuel map and narrate that for us? I am still digesting the "wall" concept.

I'll work on the current example I have with the Motec software. I'll trace the latest boost curve along side the last boost curve with the open turbine housing and the 190 shot.

 

[Alky V6]

Here's one of the latest tuneups off the nitrous, just before getting ready to start throwing the nitrous at her.

The detail lines are intersecting at 6850rpm@123kPa.

Note the area along the red line, just above the second dot from the left. You'll see this area get pumped up to supply more fuel as the turbo starts spooling up quicker and the engine starts telling me that it wants more fuel in this area.

 

[Alky V6]

This is the latest fuel map with a boost trace.

Again, the detail lines are intersecting at 125kPa, but the rpm is much better. Just over 5,000 rpm! The second view is a straight overhead of the same fuel map.

 

[Alky V6]

Here are a couple different views of the latest test fuel map. The area between 4,000 and 4,500 rpm pumped up a little more in preparation for a quicker spool when I throw the next level of nitrous shot at her.

'The wall', which should be very obvious in these views, is the point where the nitrous is turned off and the auxiliary fuel system is turned on. The massive amount of fuel squirt is used to mix with the air that is being purged from the auxiliary fuel rail when the system is activated. Without it, a dangerous lean spike would occur. After the wall, the injector pulse width drops drastically to keep the a/f mixture correct as fuel starts flowing from the aux fuel system. The aux fuel system is a constant flow system and the electronic injectors are used to help trim the fuel system as a whole.

 

[six shooter]

THANK YOU . That makes much more sense to me now. I have to synchronize both of my brain cells to follow along with your project. Keep up the good work and thanks for sharing.

 

[Alky V6]

THANK YOU . That makes much more sense to me now. I have to synchronize both of my brain cells to follow along with your project. Keep up the good work and thanks for sharing.

No problem. I actually enjoy doing it. Sometimes when I do this it helps me see things that I may have missed before.

 

[Alky V6]

Inevitably, as I push up the nitrous hit, a number of things are guaranteed to happen.

The hp level at the low/mid rpm range will increase. Shortening the 60 foot time. Surprisingly, calcs show that cylinder pressures will be safe all the way up to a 400 level shot (with alcohol). I'm sure that level will not be needed to obtain the target goal. Another interesting calc indicates a possibility of a 1.15 60 foot with the new rear tires. Is that really possible?

Exhaust mass and energy will increase, shortening turbo spool time. The tuneup will have to be carefully studied at each shot level to make sure that the combination of nitrous and boost rise does not cause a breech of cylinder pressure limits around peak torque rpm. This will make boost control during the initial launch very critical.

As turbo spool up time decreases, the required nitrous on-time will also decrease.

The torque converter stall speed will increase with each step up of the nitrous hit. Calcs indicate that with a 346 shot, stall speed could be over 3900 rpm using the present torque converter.


So, with different levels of nitrous I am doing two different tuning operations that would normally require changing of components to accomplish without the nitrous.
I am changing the spool up time that would normally require a change in the whole exhaust system and/or a change in the exhaust turbine housing size and/or a/r ratio. Or, having to compromise with a smaller overall turbo.
I am changing the stall speed of the torque converter that would normally require trying to match the correct torque converter to my particular engine combination. A shot in the dark at best and ultimately ending up with a compromise situation.
I can accomplish those two, very critical tuning operations simultaneously with the simple changing of some jets. And some think running nitrous makes things too complicated?

I realize that some may be looking over this mess and saying what the buck? I have no problem explaining any of it for you so you can grasp this. All you have to do is ask.

 

[Otto J]

Inevitably, as I push up the nitrous hit, a number of things are guaranteed to happen.

The hp level at the low/mid rpm range will increase. Shortening the 60 foot time. Surprisingly, calcs show that cylinder pressures will be safe all the way up to a 400 level shot (with alcohol). I'm sure that level will not be needed to obtain the target goal. Another interesting calc indicates a possibility of a 1.15 60 foot with the new rear tires. Is that really possible?

Exhaust mass and energy will increase, shortening turbo spool time. The tuneup will have to be carefully studied at each shot level to make sure that the combination of nitrous and boost rise does not cause a breech of cylinder pressure limits around peak torque rpm. This will make boost control during the initial launch very critical.

As turbo spool up time decreases, the required nitrous on-time will also decrease.

The torque converter stall speed will increase with each step up of the nitrous hit. Calcs indicate that with a 346 shot, stall speed could be over 3900 rpm using the present torque converter.


So, with different levels of nitrous I am doing two different tuning operations that would normally require changing of components to accomplish without the nitrous.
I am changing the spool up time that would normally require a change in the whole exhaust system and/or a change in the exhaust turbine housing size and/or a/r ratio. Or, having to compromise with a smaller overall turbo.
I am changing the stall speed of the torque converter that would normally require trying to match the correct torque converter to my particular engine combination. A shot in the dark at best and ultimately ending up with a compromise situation.
I can accomplish those two, very critical tuning operations simultaneously with the simple changing of some jets. And some think running nitrous makes things too complicated?

I have to disagree,No matter how much nitrous you can throw at it the convertor will never be right(loose enough).At best your losing potential that a looser convertor will give you with better spoolup benefits to go with it.

 

[Alky V6]

I have to disagree,No matter how much nitrous you can throw at it the convertor will never be right(loose enough).At best your losing potential that a looser convertor will give you with better spoolup benefits to go with it.

It's very simple. As engine torque increases through the use of higher levels of nitrous, the importance of converter stall decreases. One of the main reasons being the limits of chassis and traction.

As you increase the torque input into any one particular torque converter, you will also increase the stall speed of that particular torque converter.

One of the advantages that comes along with using higher nitrous shot levels is it also increases the stall level of a given torque converter so that it may not be necessary at all to change the t/c if the stall is believed to be too low when off the nitrous. Let's say that someones combo would work better with a 4000 stall T/C, but his present T/C will only stall 3500 rpm. A little shot of nitrous will do a few things. It will instantly raise the stall of the T/C, it will increase the torque level of the engine immediately for the launch, and it will make the turbo spool up quicker due to the increased exhaust mass flow. All those things work towards the ultimate limits of the chassis and traction.

An extreme example. If you can have 1,000 ft/lbs of torque at 2,000 rpm, why would you need a high stall T/C?

 

[Otto J]

It's very simple. As engine torque increases, the importance of converter stall decreases. One of the main reasons being the limits of chassis and traction.

An extreme example. If you can have 1,000 ft/lbs of torque at 2,000 rpm, why would you need a high stall T/C?

Its quite simple,At 2000 and even 4500 on your combo you are not into the power range of your motor,its that simple.
These motors have a very narrow powerband and you need to be in it at all times for max et and mph.
This is how I see it. Maybe I am wrong.
Get away from your computer simulator and go prove me wrong on the track.

 

[Alky V6]

Its quite simple,At 2000 and even 4500 on your combo you are not into the power range of your motor,its that simple.
These motors have a very narrow powerband and you need to be in it at all times for max et and mph.
This is how I see it. Maybe I am wrong.
Get away from your computer simulator and go prove me wrong on the track.

Otto, I plan to do just that. Even after all the real world data I just posted, I'm surprised that you don't see the potential, software or not.

My engine does have its particular power band... off nitrous, which has been proven to be rather flat for a wider rpm range than most would have thought (refer back to the posted datalogs). What you're not understanding is that I can make the powerband of my engine anything I want with the use of a combination of nitrous and boost. If I can change the torque of the engine between 2440rpm and whatever, I can also change the stall of the T/C within limits.

This is the most simple basic truth with any torque converter. As you increase the torque input into a given torque converter, you will also increase the stall speed of that torque converter.

If the combination of nitrous and boost level were correct at 3900 rpm to obtain a 60 foot of 1.2 seconds on a 10.5 tire, would you still think that I need a higher stall torque converter?

 

[Alky V6]

Before you answer that, I should be fair and let you know that I've already accomplished a 60 foot of 1.28 seconds using a combination of nitrous and boost. Using the same engine and the same torque converter.

That wasn't a sim run either. That was real world.

 

[lazaris]

It's very simple. As engine torque increases through the use of higher levels of nitrous, the importance of converter stall decreases. One of the main reasons being the limits of chassis and traction.

As you increase the torque input into any one particular torque converter, you will also increase the stall speed of that particular torque converter.

One of the advantages that comes along with using higher nitrous shot levels is it also increases the stall level of a given torque converter so that it may not be necessary at all to change the t/c if the stall is believed to be too low when off the nitrous. Let's say that someones combo would work better with a 4000 stall T/C, but his present T/C will only stall 3500 rpm. A little shot of nitrous will do a few things. It will instantly raise the stall of the T/C, it will increase the torque level of the engine immediately for the launch, and it will make the turbo spool up quicker due to the increased exhaust mass flow. All those things work towards the ultimate limits of the chassis and traction.

An extreme example. If you can have 1,000 ft/lbs of torque at 2,000 rpm, why would you need a high stall T/C?

I think what Otto is trying to convey is that all this tesing and theory off the race track doesnt mean much if you cant get the car hooked up and down the racetrack consistanly and competetively.

 

[Alky V6]

I think what Otto is trying to convey is that all this tesing and theory off the race track doesnt mean much if you cant get the car hooked up and down the racetrack consistanly and competetively.

What's wrong with thinking about your next tuning move rather than just aimlessly changing out turbos and torque converters and hoping you come up with a combo that works? I must tell you, it's saved me a lot of money.

There are a lot of experienced fellows on this board and I'm sure some are following this thread. Is there anything that I have stated, theory or not, that appears to be wrong? Let's discuss it.

I can tell you that there were some Buick fellows that witnessed me pull out a 1.30 60 foot with the same 2440 rpm stall torque converter at the 2007 WCN. And I was just getting the tuneup to come around then.
Doesn't that make some of you think outside the cushion lined box, just a little?

The cars best 1.28 60 foot was done at a level of tune that was lower than what was possible, due to the limitations of my chassis. I had to de-tune the setup inorder to get a sane launch attitude and I'm supposed to believe that I'm using the wrong stall. Sorry, but my real world experience tells me that the rest of you just don't have a clue about using nitrous with turbos, and are having a hard time grasping the possibilities. That's probably the main reason I've opened up my setup to all of you. To show you the true 'real world' possibilities. Anyone care to bet against me? If you truly knew me, it wouldn't be a wise decision.

 

[Alky V6]

One of the reasons why I had to de-tune my small powerband engine with my low stall torque converter.

http://www.drwtransmission.com/Videos/Vids2008/Barona 040508 short.wmv

Real world, gentlemen.

 

[lazaris]

Who said anything about aimlessly changing those things??????
I think your testing is very informative.

"There are a lot of experienced fellows on this board and I'm sure some are following this thread. Is there anything that I have stated, theory or not, that appears to be wrong? Let's discuss it."

I think those people have already spoke about that.

I think applying these theories to get the car down the racetrack consistanly and competetively is the key.
With the hard work your putting into it im sure you will.

 

[Alky V6]

Who said anything about aimlessly changing those things??????
I think your testing is very informative.

"There are a lot of experienced fellows on this board and I'm sure some are following this thread. Is there anything that I have stated, theory or not, that appears to be wrong? Let's discuss it."

I think those people have already spoke about that.

I think applying these theories to get the car down the racetrack consistanly and competetively is the key.

What I mean by aimlessly is people that just take the word of others that the latest color of turbo or torque converter, or whatever else, is going to solve their problems. Instead of taking the time to research things and find out how things tick. Then I come along with solid research, theory and proof, and I'm treated like I don't know anything. That's OK though. I understand that a lot of people do get something out of my explanations. I know you're one of them Lazaris.

Talking about consistency. With the T76 I had reached a wall. I was consistantly pumping out high 5.9 and 6.0s. To tell you the truth, it bored me to no end. I'm the kind of guy that has to tinker. And I don't mean tinkering, doing what everyone else is doing. If I reach a level, I have to move on to something different. That's probably why I'll never be satisfied to just bracket race. I live in the test and tune lanes.

 

[lazaris]

"What I mean by aimlessly is people that just take the word of others that the latest color of turbo or torque converter, or whatever else is going to solve their problems. Instead of taking the time to research things and find out how things tick."

Yes that what I was refering to. Like Dusty was saying about the converter combination. I dont think he aimlessly said thos things. I believe hes very knowledgable in this area, as well as his experiences at the track.

"That's OK though. I understand that a lot of people do get something out of my explanations. I know you're one of them Lazaris."

I do and I'm sure others do as well.

"Talking about consistency. With the T76 I had reached a wall. I was consistantly pumping out high 5.9 and 6.0s. To tell you the truth, it bored me to no end. I'm the kind of guy that has to tinker. And I don't mean tinkering, doing what everyone else is doing. If I reach a level, I have to move on to something different. That's probably why I'll never be satisfied to just bracket race. I live in the test and tune lanes."

I hear ya. The learning process never stops. If your bored bracket racing maybe try some of the heads up classes. I find them extremely fun.