Makes sense to me, based on the numbers. It's too bad that the pull didn't go out another 500 so we could see exactly where optimal is.

 

My saying that is being polite because I think you mistyped a number of things. i.e. You start out by saying torque appears to be 212 and then do your math with 225.

In paragraph 3 you state that the 6K shift brings him to 3979 in 2nd.
In the 4th paragraph you state that the 5K shift beings him to 3316 in 2nd
Then in the next paragraph you state that a 5800 RPM shift brings him to 3036 in 2nd. There is something wrong with that number, or one of the others, but it is not possible to get lower RPM in second from 5800 than it was from 5000.

No kidding. I'm trying to figure out why you're focusing on a paper loss in torque between two gears instead of the actual results.

Covered that above.

You're doing a mathematical exercise to support an incorrect theory. The loss is not occurring in the shift, it's occurring between 5000 and 6000 RPM. He's not gaining any significant horsepower and the driveshaft torque is dropping from 792 ft/lb at 5000 RPM, to 648 ft/lb at 6000 RPM. These are your numbers that you "spoon fed" me. But all you're doing by raising the RPM is lowering the torque number at the top end to make the subtraction look better after the shift. That's like government math. It looks good on paper, but it's not actually doing anything. There is no benefit to evening out the numbers if the next gear puts you on the down side of the torque curve and closer to where the engine's efficiency collapses before the next upshift.

How are you putting more torque to the driveshaft by holding the gear if it's dropping from 792 to 648 in that 1000 RPM? That's why the horsepower curve is flat. Fine, it's not perfectly flat, but there's no significant increase going on there, because the falling torque is detracting whatever you're gaining from the RPM increase. If he's losing torque and not gaining horsepower what is the point of the extra 1000 RPM? All it's doing is increasing frictional and efficiency losses, and wasting time.

Again, that's not what I said. I said that driveshaft torque drops from 792 lb/ft to 648 lb/ft between 5000 and 6000 RPM in first gear. How is that "taking advantage" of the gear ratio? It's almost the exact same loss as the 5K vs the 6K shift. Again, you're fixated on the difference between the gears and ignoring the fact that the loss has already happened before the shift. If he was gaining HP up to 6000 it would be a different story, but he's not! Holding that gear gives the same loss and puts him in a crappier part of the curve for the next gear. Your arithmetic is mostly correct, but your concept is wrong.

 

Geezus. This is why People are so dumb, today.

"The math/science is right....I just don't like it or agree with it".

******* A. Should I waste any more time trying to explain this to you? Or is it just that, a waste of time? Do you "believe in" math? Or is any mathematical explanation going to be dismissed b/c you don't "like it"/agree?

 

I'll give this one more try....see if you're capable of comprehending something new. Before getting started, you are right that my "post shift RPM" number of 3036 on a 5800 RPM shift...that is wrong. I f'ed that up, but it doesn't matter as the other two examples I showed, already show that shifting over 6k is beneficial. You're also right that I said 212tq but then used the ACTUAL number which appears as though it would be about 225 -1/2 way between 200 and 250 on that graph. Hard to tell b/c the pull stopped before that point. I'll go fix those meaningless errors for you.....

First, what is 648? I don't believe that number was in any post that I've made.
Second, Tq didn't drop from 792 to 639 over 1000 RPM; the example is straight across, one shift. When shifting at 5k from 1st, DS tq at 5k, 1st gear is 792. After that shift, in second gear, at the RPM the OP said it would be at w/ a 5k shift, you're at 639 tq at the drive shaft. K?

Here is the OP's graph....




It's hard to peg exact RPM's and tq values b/c of the scaling of the graph, and also the pull ends at something like 5800 RPM or so, The OP made note of shifting at 5k and 6k. Agreed?
The OP posted his RPM drops when shifted at those points. Can we agree on those numbers?
I posted the gear ratios for the OP's transmission...can we agree on those?

If you can agree with those "hard" data points, then can we agree on these?
If you continued the line to 6k, you'd be at about ~225 lbs. Yes? That shift would drop RPM to 3979 where the engine is making ~335tq. Agreed?
If he shifts at 5k, engine is making ~275 tq, yes? That shift would drop RPM to 3316 per the OP, where the engine is making ~335 tq. Yes?

If we can agree on those points....which honestly, look pretty obvious to these eyeballs, then let's continue....

 

Nice strawman argument.

Obviously, I was wasting my time going over all your stuff. I didn't say your math was wrong, in fact I used your math to make the case that your reasons and conclusions are misplaced. But thanks for taking the time to look at it and have nothing better in response than calling me dumb. Real intelligent.

****And okay, I see you did take the time. I apologize. When I have a moment I'll go over your response.

 

the base line pull to calibrate the dyno went to the limiter (6500) it stayed flat even there. Obviously torque continued to go down but based on the curve from 4k up... there wasn't much a reason to pull any more since it wasn't going to magically gain anything lol.

Edit: for the same reasons it didn't make sense to start the pull much lower than 1500 either.

 

They're relatively minor, but let's not just dismiss that, since you're the guy who claims to be the mathematician.

Sure was. Post 234. Your numbers sir:

This appears to be where this conversation keeps failing. Please read my earlier statement carefully:
These are your numbers, as I quoted above. You keep talking about driveshaft torque loss after the shift. I'm talking about the driveshaft torque loss between 5K and 6K in one gear only. No shifting. If you keep going on about shifting while ignoring or not seeing this we're not going to get anywhere.

Maybe I'm not phrasing it clearly, but I really get the impression you're not understanding what I'm saying. See?

If you can agree with or acknowledge that you understand what I'm saying I'll continue and comment on the rest of your post.

 

O.K. Yep I got you now. I thought you were talking about the one 792/639 event. You're comparing two events. I got it. Thanks for clearly stating that.

So back to your original question;
Yes. No.
Of course we can see tq at the DS drop from 5-6k; it's connected to the engine and the engine's tq is dropping. However, because the tq isn't dropping as fast as the RPM is increasing (HP is still going up or at least, not down), the tq through the driveshaft is still greater in 1st gear at any point from 5-6k than the tq through the DS would be if you shifted at any of those points. So...it's better to not shift. Doubt it? Pick ANY RPM between 5 and 6k...and calc out the tq's before and after shifts, or pick a point and we'll do it together here....

Let's say 5900 RPM, since that's on the high end? Where much of the torque has been "lost" (but, RPM gained).
I see ~235tq at ~5900 on that graph? 235*2.88=676 into the DS.
Shift to 2nd; 5900/2.88=2048*1.91=3911 bottom of 2nd gear. On his graph, I'm seeing ~330tq? Let give and say 335. 335*1.91=639 into the DS. So....that is less tq to the DS/wheels than if he'd held on longer in 1st.
The fast/easy way to "see" this is to look at the HP line. Exploiting HORSEPOWER is how to get the car down the track the fastest. This math proves it but you can "see" it in the graph. Simply the HP line is at a higher point at 5900, than it is at 3911....so the car can accelerate faster though the magic (math) of gearing.

 

I think this whole subplot should be reset, starting here. Because this is 100% wrong. Torque at the crankshaft does not make for acceleration. Power - and only power - makes the car accelerate. We all have heard of "Force=MassXacceleration." But the force that accelerates the car is the tractive force at the driven tires' contact patches, not the torque at the crankshaft. The things that determine the tractive force (TF) are the power at the wheels and the velocity of the car. Period, end of story. The formula, if you want to know it, is TF=375(P/V) where P is rear-wheel horsepower and V is the car's speed in MPH. It's that simple.

So going back to the OP's question about where to shift, the simple answer is that you shift so that you get the most average power at the wheels throughout the acceleration run. IOW, you want to maximize the area under the power curve for each gear you run through. Tom's method of dividing the curve into 100rpm "chunks" makes it fairly intuitive to get really close. A computer could quickly "see" the power curve by applying math functions in small chunks and then integrating those functions: there's gotta be software for this where you plug in dyno numbers and your transmission ratios and it tells you where to shift each gear. The only thing that makes it complicated is that each higher gear is closer in ratio to the next - the RPM drop between gears is less as you go up through them. So whereas you'll want to hold 1st gear significantly past peak-power RPM, you'll want to hold 2nd a little less past that peak, 3rd a little less past it than 2nd, and so on.

84 4+3, your power curve is unusual since it's basically flat to the end. That mild bump centered on 5580rpm appears to be real since it was present in both runs, so I'd want to include that in ever gear for sure. So without running any numbers, I'd think that shifting into 2nd 5900rpm and then a little with each subsequent upshift would be the ticket to getting the most power to the ground.

 

Yeah, yeah, yeah I get that.

There's the issue of the OP changing the parameters after we started this discussion. Apparently the car does NOT actually accelerate faster if you shift early on the one-two shift after all. Which tanks most of the discussion. GIGO.

If I have time away from the real world to revisit this I will, but I think it's a waste of your time and mine. Until then, let physics take over.

 

It's in first gear for like two seconds. I didn't change the parameters, I clarified what I was doing. I get what you mean though and that is wrong on my part and I should have been clearer what was going on in the data. Where the 2-3 shift occurs does effect both ET and MPH in the logs in the way I stated but it still didn't make sense why until I looked at my timing tables for those runs... It was pulling 2 degrees above 5500 (commanded to do so as these were pretty old tunes at this point) so I guess that answers a lot of it.

At the rate work is going it may still have the stock unit on it most of the spring and if so, I will get some solid A/B passes with varying shift points to see what is really up in its current form with the only changes being shifting, not one street to the next or day to day. Back to back to back. To many log files got tossed around when I got my new PC and that is on me. So my original data was flawed to begin with even though it does trend. But I will fix this, test and report back. Also, sorry for any inconvenience it has caused. -Paul

 

No apology needed on your part. I just wish I had seen your clarification when you first posted it. My fault for not reading more carefully. If I had I could have stopped trying to figure out a reason for a phenomenon that didn't exist.

 

I reached out to my welder. He said "it's been very intricate to work on." My understanding is the casting was particularly dirty and he said he just wants to make sure he gets really good bond into the casting. I told him not to worry so much on how it looks, I have burrs lol. But he has been doing it little by little between building trailers. So it will be done and he hasn't forgotten me. So I'm okay with that.

In the meantime... do I attempt tossing on the renegade and seeing if I can get it sealed up enough for a couple dyno pulls?

 

Sure! Yes!

 

Well it's sealed and it wants a ton more fuel... Like running out of duty cycle more... Grabbed second and nailed it after pedaling around in first at wide open and it danced around in second too. It's a riot lol.

Why didn't I try this sooner you ask? Well the plenum still appears to be touching the underside of the hood but it is sealed and is a hell of a ripper. It wants more fuel everywhere and it freight trains right past 4000 now lol. The first rip it went hard lean so I threw a bunch of fuel at it and it still wants more.

Edit: this is the renegade by the way...

 

This is what I’ve been trying to tell you all along. The Renegade solves most of the problems. All those people complaining about built quality (which is true and fair enough) but I’ve always thought they would have to be pretty bad to be unusable. If you think about it big port heads that use say a 1206 gasket don’t have a lot of surface area left. So if the angles are cut right and the distributor mates up all good.
with your cam and heads it will need a drink, do you have the 454 injectors fitted?

 

at 90% DC. Yes. Its a 1205 gasket and is hanging on by a thread. No shot i can use a 1206, i can see light through the top of the port. If I pop one on on the intake. Still don't understand why it's hitting the hood too but at least not as bad as last time.

But so far I don't have the massive vacuum leak i had last time. Thermostat housing weeps slightly bit overall is okay after I put gasket compound on it. The problem I currently have is the lower hole for the air pump is almost an inch too high. I have nothing I can thread my delete pulley into right now. It's definitely messed up. I just hope it doesn't start leaking down the line. It's just poor machining and some core shift according to my machinist. But it should be okay if it sealed at first.

 

And just so we're clear. I never doubted it was a stout piece. My problem mainly was it would have hated to install it and have a vacuum leak into the lifter Valley again. That is a lot of work for a fail.

 

Oh yeah man I get it. When I got mine I was unaware of all the QA issues so I just did the basic checks. ie lined up the gaskets with the bolt holes to confirm they would line up with the ports. (1205 fel pro ) in the intake and the head. Then I test fitted with standard gaskets (from a fel pro SBC set). I had to machine it to clear the oil pressure switch tee piece. After that it looked like it would fit so I rtv-ed the China walks and around the water ports and bolted it up. I feel like there wasn’t a lot of material at the bottom of the ports but it looked like the gaskets would seal. But TBH I can’t really remember. It’s been a few years now and still no leaks. I think my air box touches I hood or at least it has a some point (paint transfer). I’ve got a K&N element in there and maybe it doesn’t locate quite as well but IDK. I don’t think the air box is hitting the hood so maybe it was just the element not located properly at one point in time. I might get some putty and check it properly.
Anyway good luck with it.

 

I'm also running a K&N. It took about a week last time for it to rub the paint off the underside of the hood so I guess I'll let it ride for now. Mine is off on the upper side of the port oddly enough. The EGR passage also makes a little hump in the 6&8 runners but not horrible like others have said.

I didn't RTV the water jacket, if it seals it seals. I hate cleaning that crap off the heads. I used a little dab of indian head last time just to hold the gaskets in place on the head while installing. This time I used a scotch double stick applicator... kind of for wrapping paper but it leaves a thin film of tack like a post it note. Worked great to hold them in place.