Full boost in 1st gear?

[legacy92ej22t]

Matt's case is odd since he's using an MBC. I'd like to agree that you might not be in the gear long enough under WOT to fully spool all the way to 15psi.

Guys, it's not like my boost slowly builds to 9-10 psi in first then it's time to shift. It is at those psi levels by at least 4k rpm and holds to redline.

I'm going to recheck this tomorrow. I'll do some 1st-5th pulls and really pay attention to see what kinda boost I'm getting.

[BAC5.2]

lol, I wouldn't know. Last I saw your car, it had a boost gauge that was just hanging around (like mine is now ).

I would do the same, but my continuously slipping clutch prevents any actual pulls any more. I almost got asshole'd by a mini-van today because I couldn't grip in 2nd. I had to pull off the line at less than 1/2 throttle. Any more and slip slip slip. Both the driver and passenger were smiling and giving me the thumbs up when I pulled on them though. It was the "damn, look at that" kind of look

[legacy92ej22t]

Hahaha, ya, I know that look well. :twisted

I never expected my "load" comment to ignite such large discussion. Hehe

Vikash- I have to ask, are you just playing devils advocate? It seems that we discussed this topic in the past....

[vrg3]

THAWA - I'm not sure I understand your point. You're saying first gear is like dealing with a small amount of inertia, and third is like dealing with less inertia? Cuz I don't directly see the correlation between gearing and inertia.

Phil - Hehe, my boost gauge is still held in place by foam wedged in beside it.

Matt - Yeah, I understand you're not gradually building boost... But it's not exactly like you spend time lingering in each gear . I'm just trying to figure out why you'd get different boost in different gears.

I'm not playing devil's advocate. I just want to understand this concept scientifically. I feel like this idea that there's more load in higher gears is pseudoscience and I don't think it's actually true. I'd be very happy to see a logical argument explaining why I'm wrong about that, but that's where my logic leads.

I don't remember when we discussed this in the past... was it online or in person?

[BAC5.2]

Vikash - Maybe not for long. I still havent found that mount and I'm starting to lose hope. I do have a second radio bezel though, so if you let me know how you want things organized we can work something out (or I can make the panel, you can drill/dremel it, and I can finish it for you).

So far, vinyl is winning the finishing touch contest.

[vrg3]

Well, when I actually get other gauges I'll let you know what I think. I'm gonna buy a Westach EGT gauge (since it's cheap) and maybe an HKS electronic oil pressure gauge (since it actually uses the same pressure sensor as the fuel pressure gauge, so it should work as a fuel pressure gauge as well). I was gonna just cut a mounting plate out of sheet aluminum or something but I hadn't thought it through.

I don't mind my car looking ghetto as long as it's functionally sound.

[BAC5.2]

Is that why there is no passenger seat?

I prefer being functionally sound also, but I also like to be asthetically pleasing. Hence the fiberglass panel

Sheet Aluminum wouldn't look bad, but I like people to ask if it came like that (or at least look like it should have come like that).

I told some WRX guys about the coffee mug thing and they were looking at it and kept saying "nah, yea right." I don't know that they believe me though.

[THAWA]

THAWA - I'm not sure I understand your point. You're saying first gear is like dealing with a small amount of inertia, and third is like dealing with less inertia? Cuz I don't directly see the correlation between gearing and inertia.

I was meaning that in the string would be 1st gear, as it's easier to turn the tranny in 1st, and the rope which is heavier would be 3rd as it's harder to turn the tranny in 3rd. I didn't mean inertia or anything like that just weight.

[vrg3]

Phil - Hey now! There is a passenger seat... it's just in my garage instead of the car . Actually, I still need to patch up some wiring I did on the ABS computer before I can reinstall the seat.

Yeah, it is nice for something to look almost OEM. Did the WRX guys not believe that it was originally a coffee mug? That's pretty cool.

THAWA - That's just the thing -- I don't understand how any quantification of "harder to turn" actually affects how the engine runs.

[BAC5.2]

Nope, they saw it and thought it was an aftermarket peice.

We were talking about rice, and a guy with one of the cleanest Civics I've ever seen was like "yea, I've got a red wire loom. It's gotta be like 40hp"

and I was like "well, I've got red and black plug wires, and my WRX wheels are good for 20hp per wheel"

And I opened the hood to show them the red and black wires and I was like "oh yea, and that used to be a coffee mug" and they thought I was kidding, and I was like "I'm not kidding, it used to be a coffee mug. I got it at target. I even drank out of it." and they sorta rolled their eyes and said "ok"

[vrg3]

Hehehe... Their loss. They don't understand the utility and value of the ingenuity of Legacy Central members like legazee.

[BAC5.2]

Oh, and I think what Hardy is trying to say is this.

Say you are holding a broom stick and someone is gripping one end of it. You are turning it and they have a loose grip. Easy to turn. They tighten their grip and you have to use more energy to keep turning it at the same speed. 3000RPM's in 1st gear is relatively easy for the engine to get things going. 3000RPM's in 5th gear and the engine has a somewhat more difficult time moving the car. You need more energy to be able to move the car, so you increase revs to ingest more fuel and air to create a more powerful combustion.

[BAC5.2]

Hehehe... Their loss. They don't understand the utility and value of the ingenuity of Legacy Central members like legazee.

I don't understand it sometimes myself. Here we are making everything we need, and it's become the norm in my book. You peice this together, build that from home depot, get the other thing from a friend who made it.

I look at other car enthusiasts (mainly WRX guys and the SHO guys I know) and they buy everything or leave it stock, or slightly modify the stock peice, they rarely make things themselves.

It's kinda weird. Sorta like Jason's transition from DIY to BIY (Buy It Yourself) with the Celica crowd.

[THAWA]

Oh, and I think what Hardy is trying to say is this.

Say you are holding a broom stick and someone is gripping one end of it. You are turning it and they have a loose grip. Easy to turn. They tighten their grip and you have to use more energy to keep turning it at the same speed. 3000RPM's in 1st gear is relatively easy for the engine to get things going. 3000RPM's in 5th gear and the engine has a somewhat more difficult time moving the car. You need more energy to be able to move the car, so you increase revs to ingest more fuel and air to create a more powerful combustion.

precisely

[vrg3]

A lot of it has to do with money, I think...

I remember reading over my brother's shoulder when he was browsing one of the Supra forums and seeing a statement along the lines of, "If something cost less than a hundred bucks, I wouldn't want to put it on my car."

I think they were talking about using junkyard MAP sensors or something.

[BAC5.2]

Yea, I am not such a fan of people like that. Of course, there's no real bolt-on stuff for our cars, so if we don't make it ourselves, we don't have it on our cars, lol.

If there was, I wouldn't have to make interior peices.

[evolutionmovement]

All the more fun to blow off guys like that. Of course Supras can be pretty tough. You'll have to catch them in bad weather.

Steve

[legacy92ej22t]

I'm not playing devil's advocate. I just want to understand this concept scientifically. I feel like this idea that there's more load in higher gears is pseudoscience and I don't think it's actually true. I'd be very happy to see a logical argument explaining why I'm wrong about that, but that's where my logic leads.

Ok, I thought maybe you were doing some jedi master to padawan teaching technique. Lead them to the right conclusion but let them discover it themselves. I can't explain it scientifically, that's why I call it load.

Pseudoscience, I love it. That'd make a good song or album title.

I don't remember when we discussed this in the past... was it online or in person?

I think in person, but it was casual. It wasn't a big discussion or anything. I thought it was just mentioned in a discussion we were having. Maybe it wasn't you. I might be thinking of someone else but I've had the discussion before and "load" was always the reason for lower 1st and 2nd gear boost levels.

[vrg3]

Hardy/Phil - The thing is, though, that the engine isn't trying to maintain a constant speed. It's trying to accelerate, and it succeeds. Hmm, now that I think about it, though, that might not matter.

So you're likening the tightening of the grip (or the heavy-ificating of the string) to the increased multiplication of drag by the gearbox? I guess that's true, but how does it affect the engine other than resulting in a different amount of crankshaft acceleration? The engine is still ingesting the same amount of air and fuel per unit time, and producing the same torque, right?

Matt - Hehe, well, we have to be able to define "load" somehow... And the only definition that I've heard of in common use is manifold pressure.

I might be trying to teach with the Socratic method except that I don't actually know the answer for sure myself . I do think I'm right, but I do hope my questions will lead to either confirmation or refutation.

So are we saying that the multiplicative inverse of crankshaft acceleration can be used as a load measure? Would that mean infinite load when you're idling? That seems backwards.

[legacy92ej22t]

Oh, and I think what Hardy is trying to say is this.

Say you are holding a broom stick and someone is gripping one end of it. You are turning it and they have a loose grip. Easy to turn. They tighten their grip and you have to use more energy to keep turning it at the same speed. 3000RPM's in 1st gear is relatively easy for the engine to get things going. 3000RPM's in 5th gear and the engine has a somewhat more difficult time moving the car. You need more energy to be able to move the car, so you increase revs to ingest more fuel and air to create a more powerful combustion.

precisely

Ya, this is what I'm talking about too.

I'm having a hard time keepin' up with you guys tonight. lol

Thinking about it though, I don't know why this would create more boost (manifold pressure) from the turbo. I can see what your saying now too, Vikash. The wastegate should open at the same boost no matter what the engine is doing. I'm not sure what the answer is...

I'm going to be driving down tomorrow and I'll do some testing on I-83. It has lots of hills and I'll be able to get a good idea of what's going on in each gear, on hills and on flat.

[vrg3]

Wow. I posted, and when the thread automatically reloaded, your post was right after mine.

[legacy92ej22t]

Matt - Hehe, well, we have to be able to define "load" somehow... And the only definition that I've heard of in common use is manifold pressure.

I might be trying to teach with the Socratic method except that I don't actually know the answer for sure myself . I do think I'm right, but I do hope my questions will lead to either confirmation or refutation.

So are we saying that the multiplicative inverse of crankshaft acceleration can be used as a load measure? Would that mean infinite load when you're idling? That seems backwards.

I don't know, I'm getting confused (my sig. says it all ). At idle, the engine wouldn't be under load or very, very little.

[legacy92ej22t]

I know, that's what I mean about not keeping up tonight. I was answering your post from page two!

[evolutionmovement]

What if load were just the rsistance to the engine's work. The reason you don't accelerate equally in each gear would be greater resistance to the engine's torque (even ignoring wind resistance). The internal components would also be more strained as they fought the increased resistance of the extra torque required to move the vehicle against the higher gear ratios as well as increased friction from the greater number of tire revolutions. I think that makes sense.

Steve

[vrg3]

Matt - Yeah. Crazy.

Steve - Okay, so you say load is the torque acting against the engine's torque at the crankshaft?

Alright. Let's say the rotational moment of inertia of the crankshaft is I.

So engine_torque = load + I*crankshaft_acceleration.

So if we hold engine torque constant (and of course also I), then load is kind of the arithmetic (not multiplicative) inverse of crankshaft acceleration.

Okay. I guess I could buy that as a definition. It's kind of frustrating that I can't think of a way to measure it in realtime though.

I don't think it would strain the engine more, though, since the engine is still making the same torque. It's just having a different effect in different gears due to the friction's effect being different.