|
Originally Posted by Corky Bell
(Post 1213728)
Loads: Get a plot of chamber pressure vs crank angle. Multiply piston area times chamber pressure at every degree and plot. At each degree of crank angle, calc the inertial loads. Plot. Add the two loads together for every degree for a total load. Calc column buckling strength of the con rod. Take worst case compressive sum and adjust boost (reflecting pressure load) and rpm (inertial load) to stay below the column buckling load. |
No no, my MX6 makes 1,900,000hp at 3800rpms.
|
It doesn't say Power = HP
it says Power = P x L x A x N |
The "5252" factor would only come in when specific units are attached to the formula. If power were in KW, and torque were in N-cm, then the acutal number would be something else.
|
Originally Posted by Braineack
(Post 1213831)
It doesn't say Power = HP
it says Power = P x L x A x N
Originally Posted by DNMakinson
(Post 1213835)
The "5252" factor would only come in when specific units are attached to the formula. If power were in KW, and torque were in N-cm, then the acutal number would be something else.
|
Originally Posted by nitrodann
(Post 1213409)
I'm sorry why is there a 'goal boost' ?
Dann
Originally Posted by 18psi
(Post 1213410)
because there is such a thing as stock rods
I am talking about boost creep, not boost overshoot. Nitrodann, if you honestly don't understand why someone would want functional boost control where you can set it at your goal boost and not have it creep then why do you have a wastegate? One of the reasons I want to get ride of creep is so I can have what you have... controlled rise in boost pressure as RPM's rise. Your entire argument is based on you having a system that does not have boost creep and asking us why we want a system that functions as well as yours does. I know you don't have boost creep because if you did you couldn't have controlled rise in boost pressure as RPM's rise, you would have uncontrolled rise in boost pressure as RPM's rise. Keith |
Originally Posted by Corky Bell
(Post 1213728)
2D: You need V clamp? I Make V clamp. A/O can do both. corky You mentioned that I would need modifications to the turbo to run it on the A/O system, that is why I mentioned it was a V-band housing and that I have modified the clocking of the compressor housing... trying to clarify what turbo modifications would I need to make to run my current turbo (spud with tial V-band turbine housing) on the A/O system so I know if it is something I can do, or if I need to send it in to you. Keith |
2 Attachment(s)
Originally Posted by Twodoor
(Post 1214097)
Not just stock rods, it could be a stock 5 speed
My original example given in this thread is a 280whp NA8 VVT with a 5 speed, yes i agree. , or having 225/45/15 street tires instead of fender flares and 275/35/15 race rubber, a lot of factors go into this. I am very traction limited on 225's with 280 wheel HP, I can't imagine it being better with 350 WHP on those same 225's. you still arent quite getting this, WHP alone has absolutely fuck all to do with traction, once again, its all about the peak torque (in this case at the tyres). Lets do some numbers. 250ft lb is the number usually used as the limit of both 5 speeds and stock rods. In my experience cars with stock engines are not significantly traction limited on stock engines, with 225 street legal tyres, and a non fucked up setup. 240 ft lb (im using a small safety margin here) is over 340rwhp at 7500rpm. If it makes traction with that torque at 4000 itll make it at 7500. I am talking about boost creep, not boost overshoot. Nitrodann, if you honestly don't understand why someone would want functional boost control where you can set it at your goal boost and not have it creep then why do you have a wastegate? One of the reasons I want to get ride of creep is so I can have what you have... controlled rise in boost pressure as RPM's rise. Your entire argument is based on you having a system that does not have boost creep and asking us why we want a system that functions as well as yours does. I know you don't have boost creep because if you did you couldn't have controlled rise in boost pressure as RPM's rise, you would have uncontrolled rise in boost pressure as RPM's rise. Keith EDIT: Here is the boost map (duty cycle) used on the 280whp GT2560r 5 speed car, blurred out everything but the part in question, the full throttle part of the map. https://www.miataturbo.net/attachmen...ine=1426136068 That above map is directly off the tune, this below image is the with changes made to show what it looks like on a similar setup that has a little creep like the 5 psi at redline we have been discussing. https://www.miataturbo.net/attachmen...ine=1426136068 IE; in this thread, the creep being discussed is less that you actually want for peak performance and therefor is fine, in the exact same way that a 7psi WGA is fine even though it wont allow you to have less than 7 psi. Dann |
2d, roger, you can handle it. Outline needs later.
Power is defined as force times velocity. There are a several variations. Two are; torque times rpm, and pressure times volume rate of flow. corky |
Originally Posted by Mobius
(Post 1213745)
...In terms of compressive loads, 230wtq at 4000 vs 230wtq at 7000 is always going to be harder on the rods, because they have to endure that compressive load for nearly twice the amount of time.
But in simple terms, for a 4 stroke engine, any given cylinder is going to spend 1/4th of it's time on the power stroke, 1/4th on compression, etc. |
Also Dan has a lot of good points, and I think you guys are all arguing over semantics/terms. How about instead of a pissing contest, let's be civil and talk about how to make miata's go faster and keep them reliable?
|
Brain trolled Dann, and I jumped in, Dann got his panties in a wad as always and went off on me, as always, while brain stepped back and laughed at his successful troll.
I can't believe I have to spell it out for you guys. :fael: |
Originally Posted by patsmx5
(Post 1214884)
??? I don't get this part. Which is worse? And why? I get number of cycles is higher at higher RPM, that is obvious.
But in simple terms, for a 4 stroke engine, any given cylinder is going to spend 1/4th of it's time on the power stroke, 1/4th on compression, etc. At 7000 RPM doing the math you see that each compression event only lasts 2.15 milliseconds. As was pointed out to me in another thread, if you have the same torque output from the engine at two different RPM's the higher piston speed moving away from the flame front at higher RPMs reduces the peak load on the rods even at the same total torque output. Keith |
Originally Posted by Twodoor
(Post 1214903)
....
As was pointed out to me in another thread, if you have the same torque output from the engine at two different RPM's the higher piston speed moving away from the flame front at higher RPMs reduces the peak load on the rods even at the same total torque output. Keith Basically if you measure cylinder pressure vs crank position and plot that at both RPM points, for the same torque, the motor turning slower will have higher peak pressure, as the 10-90% combustion time will occur with the piston closer to TDC than an engine turning faster. |
1 Attachment(s)
|
You want me to post the screenshot of the conversation me and Scott were having laughing at you on G-chat?
Or you wanna cry some more? hurr durr |
I feel that it would be necessary for anyone but you and Scott to believe what you are saying.
|
I dont even know what this thread is about.
|
Originally Posted by 18psi
(Post 1214901)
Brain trolled Dann, and I jumped in, Dann got his panties in a wad as always and went off on me, as always, while brain stepped back and laughed at his successful troll.
I can't believe I have to spell it out for you guys. :fael: |
no i actually made errors in my argument.
|
| All times are GMT -4. The time now is 09:35 PM. |
© 2024 MH Sub I, LLC dba Internet Brands