John, I really don't see a problem here. There is a lot to be learned if you read between the lines...
There is always the option of not clicking on it.
Picking a New Full Race Stall Speed
- Thread starter Alky V6
- Start date
John, I really don't see a problem here. There is a lot to be learned if you read between the lines...
There is always the option of not clicking on it.
What?????
There is more to tuning than 3 cells up top? I thought you let the O2 do the rest?? :biggrin:I considered it, but the way I am, and learning a new fuel, I wouldn't of liked being under the clock. I took my time trying different ideas and thoroughly learning the fuel.
If the idea would have been to throw a quick race tune on the car, that would have come about much quicker. This being a learning project, I took my time and experimented a lot. And I mean A LOT.
If you watch most alky racers, you will see them change the oil every one or two runs, even with being towed to the lanes and back to the pits. With the fueling dialed in, a person can cruise to the staging lanes, cruise back to the pits after the pass without a tow vehicle, and go multiple events before changing the oil. That is the difference between dialing in a methanol fuel map and just throwing a quick tune on the car. Most of that also has to do with running an intercooler.
I've been interested lately myself. A dyno shop moved in right across the way lately.
1) The plan was to build an efficient engine using the heads as the core for the combination. When I bought the M&As, they were the only aftermarket heads available. They are a first generation run. The rest of the combination was based around making them as efficient as possible. I did do simulation work to come up with the total combination. If you've ever seen pictures of the first version of the engine, you'd have noticed that it followed what everyone else was doing at the time. Aftermarket bolt-ons. The latest version uses all custom specs worked out on a sim.
At the time, I didn't feel I could afford a Stage II project.
The target was 650 hp. I wasn't looking to compete with anyone but myself, if you know what I mean.
2) The CI was picked through the sim using the flow numbers I obtained from the heads. Poor numbers at that.
3) Yes, you saw the same thing I did then. Changing the stall really didn't affect the fuel map much, so all that work on the fueling with the low stall turned out to be time well spent.
After the turbo change, it was a little over a day to get the tune track ready. What threw me off was the lean spiking on the nitrous hit. That is what took all this time to figure out. And, by the way, a dyno would not have helped me figure that out any sooner. After that was understood, it was just a matter of stepping up the nitrous hit size to find the limits of the tuneup. When I say tuneup, I mean the limits of the combination as a whole. The engine, turbo, converter, nitrous system. The 60' was my judge.
With the smaller turbo, nitrous and the tight TC, that combination worked extremely well, but the turbo was out of breathe on the top end. I wanted the heads to be the flow limiter, not the turbo.
As with any combination, as you step up the performance you're going to find a wall. Where the turbo size was the wall with the previous combination, now the TC had become the wall, and it was limiting how high I could go with the nitrous shot. Now with the TC change, it has opened the door to increasing the nitrous shot again. So the tuning of the combination is still being stepped up. As the nitrous shot size is increased, I may find that the lower than anticipated stall of the new TC just may work into being the ticket. With each 20 hp shot size increase, I usually get about 200 more rpm stall speed out of a TC. Instead of changing out the TC with one that is looser to provide more stall for the launch, that may also be looser on the top end, I can use the nitrous to push the stall higher for the launch while maintaining efficiency for the top end. That is the tuning factor that makes it more difficult for TC techs to match a TC to my combination. That's not something they're used to factoring in day in and day out. Especially when you can't give the tech a concrete figure for the actual working hp rating of the nitrous shot.
4) The urgency to step to the Stage II project is not there. As you eluded to, the Stage I project is approaching the goal. The time and expense of switching to the Stage II project may not be needed.
A low stall TC would allow you to reach even more spots on the fuel map. Dyno or no dyno.
I've always found the top end to be the easiest area to tune. Even with the auxiliary fuel system in the mix. The nitrous region, especially being masked by a 14.64:1 reading on the a/f meter has been the challenging part. The 60' numbers turned out to be the best tool for that region. That and the lean intake backfires that told me I was getting too lean.
Tuning the top end on the track has allowed me to go as far as my present fuel system is allowing me to go. There would be no use in putting it on the dyno for tuning the top end unless the fuel system delivery was increased. That will be looked into after I'm happy with the launch, the boost controller setting, and whether or not I can get the chassis set up to where it might take on more power.
Since you knew you were going to switch to a higher stall speed it really doesn't matter. You said yourself the tune didn't change much when you went to a higher stall. The inverse is also true. You could have done the tuning with the higher stall in and been addressing the other issues. (i.e. spoolup, chasis).
You are completly wrong. You will take a year to work on spoolup, etc.. and not do the same when dialing in your top end? When you put it on the dyno, you can change the A/F up and down and see what it does to the hp AT DIFFERENT RPMS. You can do the exact same thing with timing. You can also analyze the hp curve to determine shift points, convertor information, area under the curve, etc... I won't even talk about your boost controller settings.......
I have already said too much. A month from now, you will say you knew you were going to have to get it on the dyno and that you just needed to put the cart in front of the horse.
It's very simple to look at what I've done, after the fact, and say that I would have seen the same phenomenon I was getting with the nitrous hit, even after changing to a different TC.
You see, I was taught that when a problem presented itself, you solve that problem before you move on. That's basic troubleshooting and tuning practices 101. You change one tuning parameter, or solve one problem at a time to see the affect, before moving on to the next task.
When nitrous is involved, the inverse is not true. If you go to a tighter TC and the particular combination allows the boost to build quickly in the rpm band, the fueling will be going through high map cells earlier in the rpm band. You will never reach those cells with a high stall TC.
For instance, a high stall TC at launch may cross over into the boost region of the map at 4500 rpm, where as a tight TC with nitrous assist and a relatively small turbo will cross over into the boost region closer to 3000 rpm or sooner, depending on the exact combination. You will never see those regions with a high stall TC, even with nitrous assist. So, if a person were to move to a tighter TC for whatever reason, they'd better be looking at the tuneup, because the engine may be going into uncharted territory on that fuel map, depending on the combination.
At $50 an hour I disagree.
Cal, do you think all that track time was spent on only changing things around in one small area of the fuel map? You don't think that I played around with timing for the top end, after making changes in other areas that I was more concerned with?
After a run, I analyzed every aspect of every section of the fuel map. Some areas needing much more attention (the nitrous section) than others, but I didn't ignore the other areas of the tune because of one special problem I was having. I don't put blinders on when I'm studying a fuel table.
I'm not going to get into teaching everyone the different aspects of different sections of the fuel table for different operations of the engine from startup to cruising back to the pits, but all aspects were studied after each pass. Many aspects were finalized very early on. The nitrous section needed much more attention. You don't think that after a year of fighting the nitrous tune, that I managed to dial in the top end? Come on now. Now you're just trying to be insulting. I don't mind if you want to share some tuning ideas or maybe gain some knowledge from my unique experiences, but if your mission here is to try to belittle me, move on. I don't have time for that.
The track timeslip and datalogging does very well in replacing the dyno. And when all that dyno time is done, it still comes down to what she does on the track. If the loading is a little different on the dyno than the car might see on the track, adjustments will still need to be made. It should be close though. One thing that can't be adjusted for on a dyno is altitude for an open loop type of tuneup.
If you had any idea how much time I spent changing around the fuel table, experimenting with this and that, you wouldn't be saying that.
When I started out with the methanol, I spent an enormous amount of time just playing around with the idle to light load regions. Then came the TC stall point. That didn't take long to square away. You don't need a dyno for any of that. That would just be a complete waste of dyno time. This is where I spent most of my time. Playing with different mixtures, seeing how the engine reacted from cold start through warmup and beyond with the different mixtures. Interesting stuff when a person is first dealing with methanol fuel.
Sure I could have thrown something on the engine real quick where it ran and moved acceptable for a race car, but I was looking into really studying the new fuel. Methanol has a very, very wide tuning range, and I was determined to study every part of that range, from rich to lean. A 30% range.
The point where I started putting some load on it was not really a big deal. I launched the car in front of the shop through first gear and found the basic curve. Again, it took about a week of that because I was trying out the complete tuning range of the fuel. Sometimes I spent a few hours studying one datalog before making changes for the next test. That would have been real pretty at the dyno shop.
After that, it was track time. The run that I made at the WCN in Vegas, I think it was 2005, that's when I met you Scott, those were the first full 1/4 mile passes with the car with that ver 2 buildup. It blew during that event due to the mixture being too lean. I was still learning the sweet spot for the mixture, and the affects of starting line engine temperature on the methanol mixture strength. Or, should I say, that was the event that instilled in me those particular tuning points.
This latest engine build, version 3 had its maiden 1/4 passes during the WCN in Arizona 2007. I don't know why it turned out that I was finalizing tuneups during WCN events, but that's just how the timing turned out. Saturday was a challenge until I had made a major change in how the aux fueling was timed with the nitrous injection. After that change, the car made the quickest 1/4 mile pass, and the second quickest 1/8 time it has ever done since then. That was a hoot of a day. I think you were there, Cal, helping out some others there with their tune.
After that, it took awhile for me to decide to move away from the T76. But during all those early years, I can remember hearing the same thing. You need a looser TC. Never mind that the combination was getting 1.28 60 foots. With that combination people that were nagging me about the TC really had no clue about my combination. They were used to the general things people were doing at the time. I was, and still am, not following the herd. Sorry if that disappoints some of you.
2 hours of dyno time is comparable to a full track day for me. I understand the difference in fuel regarding the tuning aspect, as I am undergoing the same process. I agree with your TC tuning concept but common sense and 2nd hand experience usually wins. I went to Dusty for a convertor for my new combo and without making a single run I'm betting it's too loose. Since my motor is based around a high velocity/low rpm exhaust design it currently flashes to 5000rpm in 3/10's of a second with zero boost. I'm hoping it has good coupling characteristics at a higher rpm(7500max)bute'll see. In the mean time I will test and determine what's needed but at least I'll have a good baseline and send the PTC convertor back for the free re-stall if needed.
BTW, at 2850 my 76gtq maxed out at 780rwhp. After installing the 47/88 I only picked 2/10's in the 1/8mi but the fuel map only changed in the 3500 -5000rpm area.
BTW, at 2850 my 76gtq maxed out at 780rwhp. After installing the 47/88 I only picked 2/10's in the 1/8mi but the fuel map only changed in the 3500 -5000rpm area.
I'm not trying to say that dyno time wouldn't be nice. It's a nice luxury, especially if it's a customer's car that has to get out in a timely fashion.2 hours of dyno time is comparable to a full track day for me. I understand the difference in fuel regarding the tuning aspect, as I am undergoing the same process. I agree with your TC tuning concept but common sense and 2nd hand experience usually wins. I went to Dusty for a convertor for my new combo and without making a single run I'm betting it's too loose. Since my motor is based around a high velocity/low rpm exhaust design it currently flashes to 5000rpm in 3/10's of a second with zero boost. I'm hoping it has good coupling characteristics at a higher rpm(7500max)bute'll see. In the mean time I will test and determine what's needed but at least I'll have a good baseline and send the PTC convertor back for the free re-stall if needed.
BTW, at 2850 my 76gtq maxed out at 780rwhp. After installing the 47/88 I only picked 2/10's in the 1/8mi but the fuel map only changed in the 3500 -5000rpm area.
We're actually going to tune Chad's car on the dyno. It'll be our first experience using a dyno to tune a car from square one. In the past, I have just used the dyno to check a tune after doing simple street tuning.
Zero boost. Hmmm. That should be interesting. Is the nitrous still in the mix? I assume the 5000 is not with the nitrous.
Scott. Something you might try if your tuneup is developed to this point. Use the transbrake to hold load on the engine through 1 second of nitrous on-time. That will give you an idea of what the TC is going to do with the nitrous, and what kind of rpm/boost relationship you might end up with.
I would imagine that even without the nitrous you would be getting some boost with those twins by 5000 rpm.
Actually, when I step up the shot size and do a static nitrous test like that, I start out with a half second test first. If everything looks dandy, then I step a little closer to the one second mark, and so on, until I reach one second.
I know some are probably cringing. A nitrous shot while on the transbrake. If the tuneup is correct, there will be no problem. Heck, I was doing it with a 2400 rpm stall TC. Piece of cake. A hit on a high stall is much safer.
I would imagine that even without the nitrous you would be getting some boost with those twins by 5000 rpm.
Actually, when I step up the shot size and do a static nitrous test like that, I start out with a half second test first. If everything looks dandy, then I step a little closer to the one second mark, and so on, until I reach one second.
I know some are probably cringing. A nitrous shot while on the transbrake. If the tuneup is correct, there will be no problem. Heck, I was doing it with a 2400 rpm stall TC. Piece of cake. A hit on a high stall is much safer.
jimmymorrisonjr
Member
- Joined
- Jun 16, 2009
Confused
I really can't understand one thing that is bothering me. Why would it be better to tune with the wrong converter? If you can't tune a few cells in the table with the new converter as accurately, they can't be too important to accomplish a good running car. I would think you would change the mechanical combo as soon as you determine a mis-match so your tune can concentrate on the cells that will be most relevant when the combination is right. I really have almost no experience with tuning so this is a legitimate question.
I really can't understand one thing that is bothering me. Why would it be better to tune with the wrong converter? If you can't tune a few cells in the table with the new converter as accurately, they can't be too important to accomplish a good running car. I would think you would change the mechanical combo as soon as you determine a mis-match so your tune can concentrate on the cells that will be most relevant when the combination is right. I really have almost no experience with tuning so this is a legitimate question.
If you stopped trying to teach and tried to learn a little, you might find that the advice that has been given to you is actually pretty good. You have several qualified people here TRYING TO TEACH YOU a few things. I think the frustration come in when you refuse to listen.
What I (and probably Scott) am saying is the dyno is not a replacement for the race track. It is just another tool that can allow you to get the car tuned. Like any tool, it is only as good as the guy using it. You had already said it would be of no use, yet had never tried it. I can just about guarantee you will learn something from it, good or bad.
You would not end up with a "better" tune. You would end up with a "decent" tune that would allow you to better judge whether the present TC was going to do the job for you or not.
A good example is my case with the T76 combination. Everyone was saying that the TC I was using was going to be too tight to do the job. The more the tune came in, the better the results became using that tight TC, until finally, it turned out that the tight TC was absolutely perfect for the combination. If I had listened to everyone and changed the TC before I had finished tuning in the engine, I would have ended up with a TC that was too loose for the combination when I had finally finished tuning in the engine.
Cheeseburger
Active Member
- Joined
- Jan 25, 2004
From what i can see and read this is more of a documentary on what Don is doing.
But he seems to request some input which always falls on deaf ears......
Maybe i'm wrong and sorry if i am......
But he seems to request some input which always falls on deaf ears......
Maybe i'm wrong and sorry if i am......
A dyno is not necessary for tuning in idle and off idle, cold starting, warm starting, warm up enrichment, light loading, or testing different mixtures strengths under the previous listed conditions. There is a lot of preliminary tuning that takes up the majority of time tuning in a car that can be done very well without a dyno.
Yes. A dyno is just another tool. A tool that can be worked around if one chooses to. If one chooses to do the job quicker, then a dyno is a very handy tool.
Cal, have you ever tuned without using a dyno?
You're right. I start most threads with the idea of treating it as a diary or Blog of my experiences with the car. Since I'm doing things that no one else in the Buick community is doing, I thought some might find it interesting to read up on what I'm doing. Judging by most of the posts so far, I think there are some that would rather I didn't share anything with you at all. I'm not sure why, but I get the impression that I'm encroaching on someone's territory or something? I'm not sure how I'm doing that since I'm doing things that I'm sure no one else is going to pick up and try themselves anyway.From what i can see and read this is more of a documentary on what Don is doing.
But he seems to request some input which always falls on deaf ears......
Maybe i'm wrong and sorry if i am......
Who really knows though. If I had stumbled on someone that was eager to give up details of a very controversial combination, I would be eating it up myself. Knowing that about myself, I thought it would be nice to hopefully do that for others that are interested in reading about it.
If others choose to contribute to make for interesting conversation, I certainly welcome it.
Those that choose to criticize me in a manner that is only meant to cut me down, well, I've been dealing with that for a very long time. I'm used to it. It really doesn't bother me, so don't let it bother you.
