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liquid00meth · 06-21-2004, 04:58 PM

10.1 is reasonable. It is not what I would run personally, but for the purposes of this argument, it is agreed B)

nismogod · 06-21-2004, 05:29 PM

just out of curiousity, no one is claiming that any internal combustion engine is 90% efficient are they? because that's ludacris. and i dont mean the guy from the music.

pissedoffsol · 06-21-2004, 07:24 PM

Quote:

Originally posted by radnulb@Jun 21 2004, 04:58 PM
I will disagree with pissedoffsol on the built single cam turbo issue.
Using aftermarket rods and forged pistons is kinda retarded, but there are a couple of budget alternatives that make sense to me.

oh indeed... even the panda setup is fine.

but to spend a G on sleeves, 500 on rods, and 400 on pistons on a d-block, to me, is retarded.

StyleTEG · 06-22-2004, 12:12 AM

Quote:

Originally posted by nismogod@Jun 21 2004, 04:29 PM
just out of curiousity, no one is claiming that any internal combustion engine is 90% efficient are they? because that's ludacris. and i dont mean the guy from the music.

volumetric efficiency and the efficiency of an entire combustion motor are two completely different things.

MikeBergy · 06-22-2004, 02:58 AM

Interesting read. How does a higher compression piston by itself create more vacuum? It seems that the amount of vacuum created by a high cr piston versus a low cr piston would be trivial at best...Most of the VE gained by NA motors is gained at high lift points in the valve's cycle. I would have explained the whole "off boost" power gains as merely a result in higher effective compression off-boost. The more cylinder pressure the cylce has to start with, the more power is going to be produced, because the overall pressure in the cylinder will be higher. I've heard the high cr/low boost vs. low cr/high boost argument before. Neither is better than the other, it just depends on what you are looking for as far as how you want your motor to behave. High CR/Low Boost motors would seem to have a more linear response than a low cr/high boost motors. You wouldn't see as much of a surge in power; that would appeal to me, because I like the idea of linear power curves, and being able to predict how my car is going to react when I mash the throttle. I honestly don't want to just smoke the tires all day, and that seems to be the case with most low cr/high boost motors: they are kind of just off or on, not really any in between. I don't have experience driving a high boost motor, but reading about others' experiences with burning thru 1st and 2nd gear, I don't think I would like that kind of power delivery. But what can I say, I'm not really into turbos; NA is more fascinating; and the technology of turbocharging has pretty much reached its zenith as far as I have seen; NA is where all the technology is at. Just look at all the new motors that companies have been building these last few years for both bikes and cars.

liquid00meth · 06-22-2004, 10:34 AM

Quote:

Originally posted by nismogod@Jun 21 2004, 04:29 PM
just out of curiousity, no one is claiming that any internal combustion engine is 90% efficient are they? because that's ludacris. and i dont mean the guy from the music.

no, the volumetric efficiency of a vtec head is claimed to be 90%. It doesn't mean 90% engine (fuel -> power) efficiency, we all know that is wrong.

what that 90% means is that 90% of the possible maximum air/fuel mixture at 1 atm gets into the cylinder

liquid00meth · 06-22-2004, 10:40 AM

Quote:

Originally posted by MikeBergy@Jun 22 2004, 01:58 AM
and the technology of turbocharging has pretty much reached its zenith as far as I have seen; NA is where all the technology is at.

negative. There are experimental turbo designs on the table in R&D facilities all over the place. I can't remember how they work off the top of my head, I read about it a while ago. But there is no chance that the technology is maxed out.

StyleTEG · 06-22-2004, 12:06 PM

Quote:

How does a higher compression piston by itself create more vacuum? It seems that the amount of vacuum created by a high cr piston versus a low cr piston would be trivial at best

If you understand how vaccum works, it makes a lot of sense.

The area above the piston grows at a larger rate with the higher compression piston. This creates a larger pressure drop, and the atomospheric area outside of the valves is pushed in to try and equalize the pressure. But because there it is a lower pressure zone (than the low cr pistons) it travels in at a faster rate. This equals to better cylinder filling.

This is simmilar to how ITBs work so well. When the ITBS are wide open, and the air is traveling to try and equalize the low pressure created by the piston returning to BDC. At some point the intake valve is going to close so the air still traveling will bounce OFF the closed intake valve and create a low pressure zone. Much like the cylinder itself, air will travel into that zone at a faster rate to try and equalize the pressure.

At the right RPMs (depending on the length and diameter of the ITBS) the intake valve will open again as the air is trying to equalize and enter and overfill the cylinder at the faster rate.

radnulb · 06-22-2004, 12:19 PM

werd to your harmonics StyleTEG.

MikeBergy · 06-22-2004, 02:12 PM

Quote:

Originally posted by StyleTEG@Jun 22 2004, 09:06 AM

If you understand how vaccum works, it makes a lot of sense.

The area above the piston grows at a larger rate with the higher compression piston. This creates a larger pressure drop, and the atomospheric area outside of the valves is pushed in to try and equalize the pressure. But because there it is a lower pressure zone (than the low cr pistons) it travels in at a faster rate. This equals to better cylinder filling.

This is simmilar to how ITBs work so well. When the ITBS are wide open, and the air is traveling to try and equalize the low pressure created by the piston returning to BDC. At some point the intake valve is going to close so the air still traveling will bounce OFF the closed intake valve and create a low pressure zone. Much like the cylinder itself, air will travel into that zone at a faster rate to try and equalize the pressure.

At the right RPMs (depending on the length and diameter of the ITBS) the intake valve will open again as the air is trying to equalize and enter and overfill the cylinder at the faster rate.

I get all of the above except for the part in bold. I don't see how the higher cr piston is going to effect a more rapibidly growing area above the piston, given the same bore and engine rpms. I am not saying that you are wrong, just saying that you sound like you are basing your argument on the wrong premises. If you are saying that by having a larger piston dome, the volume above the piston in the chamber increases at a faster rate than that by a low cr piston, I completely understand, and it is just a mix-up of units. But I don't think that miniscule amount of suction increase at low valve lift is going to make a big difference. Combined with a good flowing intake manifold and ports, I could see this being a more appropiate place to look for off boost power, but by itself would not do a whole lot. Most volumetric effiency gains are made at high valve lift situations, and by the time the valves are close to fully open, the vacuum difference between a high and low cr piston would be a moot point.

StyleTEG · 06-23-2004, 03:54 PM

Yes volume, not area sorry.

Quote:

But I don't think that miniscule amount of suction increase at low valve lift is going to make a big difference.

....

Most volumetric effiency gains are made at high valve lift situations, and by the time the valves are close to fully open, the vacuum difference between a high and low cr piston would be a moot point.

Sounds like a whole lot of guessing to me.

Before throwing away potential benifits of a different setup, maybe you should try and find some hard evidence that its not worth considering.

MikeBergy · 06-23-2004, 04:13 PM

Quote:

Originally posted by StyleTEG@Jun 23 2004, 12:54 PM
Sounds like a whole lot of guessing to me.

Before throwing away potential benifits of a different setup, maybe you should try and find some hard evidence that its not worth considering.

Well it actually wasn't my my thoughts, I must confess, the topic was addressed on m24x.com, and the guy for RLZ? I think was saying that. I am in no way in a position to do testing like that, and for the most part, it really is just a situation where you have to test two different pistons on the dyno, and see where the differences lie. It would be a guess for me, but like I said, I am just relating information I have seen posted by someone else with lots more building experience with me. Keep in mind that most of the VE problems come up with NA setups, not turbos, and most people building boosted motors are looking for the quick bang for the buck, not dumping a gagillion dollars into a race ready, highly responsive on-and-off boost motor. So basically I am in agreement with radnulb, recomending a lower CR and easing up the tuner's task of getting it dialed in. Tuning and dyno cost money, and the less time that is needed to get it all dialed in, that is more money you could be saving to put back into other areas of your car. But I see what you are saying, and I would prolly spend the extra cash to do a high compression build, because, like I said before, I am an NA guy, and a linear engine response is going be a lot more likely with the setup you were talking about.

StyleTEG · 06-23-2004, 05:00 PM

Yes, Rocket has discussed this subject before. And it isn't easy to measure. However I don't think it should be dissmissed as "minimal" if no one has any real evidence one way or another.

I still have to disagree with some of your logic though.

While yes, most guys are looking for quick up and go when it comes to boost... you are already talking about rebuilding the engine in this situation. (What CR to go with, when picking new pistons).

So that isn't going to save you any money.

And as far as tuning, that is the last place I would want to try and speed up and get dialed in. As far as running boost is concerned, I would rather he spent an extra hour or two making sure everything is set.

The money you don't spend replacing your engine is money that can be spent elsewhere

nismogod · 06-24-2004, 05:32 PM

neglect the .7:1 compression difference and add yourself some nitrous. lol. sorry, not a valid point in this conversation. i like linear power curves. mmm. lol. i'm glad to see that people on this site have wonderful linguistic skills along with physics knowledge. i think i need to go back and finish my degree. perhaps i can make a difference somewhere

as far as tech being maxed out in any field, especially mechanics, i dont think its possible, atleast, not within any amount of time i will ever be alive.

Import Builders · 06-24-2004, 06:30 PM

Quote:

Originally posted by Blanco+Jun 24 2004, 03:55 PM--><div class='quotetop'>QUOTE(Blanco @ Jun 24 2004, 03:55 PM)</div><div class='quotemain'> <!--QuoteBegin-StyleTEG@Jun 23 2004, 04:00 PM
Yes, Rocket has discussed this subject before. And it isn't easy to measure. However I don't think it should be dissmissed as "minimal" if no one has any real evidence one way or another.

I still have to disagree with some of your logic though.

While yes, most guys are looking for quick up and go when it comes to boost... you are already talking about rebuilding the engine in this situation. (What CR to go with, when picking new pistons).

So that isn't going to save you any money.

And as far as tuning, that is the last place I would want to try and speed up and get dialed in. As far as running boost is concerned, I would rather he spent an extra hour or two making sure everything is set.

The money you don't spend replacing your engine is money that can be spent elsewhere

While I'm following this quite closely, I have to say this. I'm not about to spend $1000-1500 on dyno time for 1 point in compression, for a negligible pre/off-boost difference. If you can show me dyno charts of the same engine, running both 9.3:1 and 10:1 pistons, that shows both long-term reliablity and why I should worry about a .7:1 difference, I'll consider it. I don't have enough money to think outside the box when it comes to my engine build, I'm going with what's been tested and proven. [/b][/quote]
I want the temperature outside to be 74 degrees every day of the year, but its not, lets discuss why its hotter some days and colder other days. Thats what discussing why different compressions create different vacuums is to me. Why discuss something you can't change? if you buy X pistons, they create X vacuum. End of story.

Also, on some of the higher compression motors, if you stick your hand over the T/B or ITB it will suck it so hard, it will HURT your hand.

I datalog all of what your talking about all the time, thousands of times. I will go ahead and record some video's of high vs low compression on anf off throttle for comparisons.

Thats all you have to do, real easy. I just see 0 point to it. You can't change it.

74 degrees would be nice huh? Golf....

Jeff

nismogod · 06-24-2004, 07:20 PM

74 degrees would be bad ass.

StyleTEG · 06-25-2004, 12:24 AM

Quote:

Originally posted by Blanco@Jun 24 2004, 03:55 PM
While I'm following this quite closely, I have to say this. I'm not about to spend $1000-1500 on dyno time for 1 point in compression, for a negligible pre/off-boost difference. If you can show me dyno charts of the same engine, running both 9.3:1 and 10:1 pistons, that shows both long-term reliablity and why I should worry about a .7:1 difference, I'll consider it. I don't have enough money to think outside the box when it comes to my engine build, I'm going with what's been tested and proven.

$1000 - 1500 in dyno time, are you nuts?

It is not THAT hard to tune for 10:1. I have seen it done in two hours, reliably. I have seen 10.3:1 tuned in a few hours, reliably.

Why speculate if you have no clue one way or the other?

If you are braking traction at stoplights I doubt its because of the off-boost performance.

nismogod · 06-25-2004, 06:35 AM

just as a heads up.... TITAN MOTORSPORTS, which is local to me, charge 95 an hour if you tune it, and 145 an hour if they tune it. they said between 1 and 2 hours to tune my NA vehicle.

StyleTEG · 06-25-2004, 10:36 AM

I agree that its not something you HAVE to do, its an option that some might take and not others.

But to make outrageous claims, or speculate on the difference in dyno time, or performance, doesn't benifit anyone.

radnulb · 06-25-2004, 11:07 AM

Titan has done some good work... Familiar with the DIY tools not just Hondata too...

pissedoffsol · 06-25-2004, 03:22 PM

my tuner is 400 flat for pump gas, 500 flat for pump/race tunes.
+ dyno cost/hr at whatever shop you go to with him
my local dyno is 100 first hr, 75 for 2nd, 50 thereafter.
so if it takes 2 hours, its roughly 575-600 bucks for pump gas.

StyleTEG · 06-25-2004, 05:49 PM

Quote:

Originally posted by Blanco@Jun 25 2004, 02:16 PM

Chill out dude. I already said that I don't know shit about dyno time. You could have been helpful, instead of condescending. Since, you know, being condescending is such a benifit to people. And if you're not speculating on the differences in performance, why the hell have you been whoring up my thread?

I wasn't being condescending. Sorry if you felt that way.

I was just stating that speculation is unecissary. A mild boost/mild CR motor has its advantages. They are proven through physics. Blindly stating that it doesn't do anything is just going to mislead people with the same questions you had.

nismogod · 06-25-2004, 09:39 PM

Quote:

Originally posted by radnulb@Jun 25 2004, 10:07 AM
Titan has done some good work... Familiar with the DIY tools not just Hondata too...

actually, recently they have become well versed in hondata/uberdata programing. sorry to post irrelivant info.

06-21-2004, 04:58 PM	#26
liquid00meth Senior Member Join Date: Nov 2002 Location: Laconia, NH Posts: 3,201 iTrader: 0 / 0% Rep Power: 47	10.1 is reasonable. It is not what I would run personally, but for the purposes of this argument, it is agreed B) __________________ "Our enemies are innovative and resourceful, and so are we. They never stop thinking about new ways to harm our country and our people, and neither do we." -The thought provoking George W. Bush

06-21-2004, 05:29 PM	#27
nismogod Senior Member Join Date: May 2003 Location: Deltona, FL Posts: 1,031 iTrader: 0 / 0% Rep Power: 24	just out of curiousity, no one is claiming that any internal combustion engine is 90% efficient are they? because that's ludacris. and i dont mean the guy from the music. __________________ Power is nothing without Control.

06-22-2004, 12:19 PM	#34
radnulb Senior Member Join Date: Sep 2003 Location: Sinsinnaty, Ohio Posts: 674 iTrader: 0 / 0% Rep Power: 19	werd to your harmonics StyleTEG. __________________ PGMFI.org founder and DIY ECU tuning advocate Just say no to rice...

06-23-2004, 05:00 PM	#38
StyleTEG Senior Member Join Date: Oct 2003 Posts: 217 iTrader: 0 / 0% Rep Power: 15	Yes, Rocket has discussed this subject before. And it isn't easy to measure. However I don't think it should be dissmissed as "minimal" if no one has any real evidence one way or another. I still have to disagree with some of your logic though. While yes, most guys are looking for quick up and go when it comes to boost... you are already talking about rebuilding the engine in this situation. (What CR to go with, when picking new pistons). So that isn't going to save you any money. And as far as tuning, that is the last place I would want to try and speed up and get dialed in. As far as running boost is concerned, I would rather he spent an extra hour or two making sure everything is set. The money you don't spend replacing your engine is money that can be spent elsewhere __________________ <a href=\'http://www.limitedslipmotorsports.com\' target=\'_blank\'>http://www.limitedslipmotorsports.com</a>

06-24-2004, 05:32 PM	#39
nismogod Senior Member Join Date: May 2003 Location: Deltona, FL Posts: 1,031 iTrader: 0 / 0% Rep Power: 24	neglect the .7:1 compression difference and add yourself some nitrous. lol. sorry, not a valid point in this conversation. i like linear power curves. mmm. lol. i'm glad to see that people on this site have wonderful linguistic skills along with physics knowledge. i think i need to go back and finish my degree. perhaps i can make a difference somewhere as far as tech being maxed out in any field, especially mechanics, i dont think its possible, atleast, not within any amount of time i will ever be alive. __________________ Power is nothing without Control.


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06-24-2004, 07:20 PM	#41
nismogod Senior Member Join Date: May 2003 Location: Deltona, FL Posts: 1,031 iTrader: 0 / 0% Rep Power: 24	74 degrees would be bad ass. __________________ Power is nothing without Control.

06-25-2004, 06:35 AM	#43
nismogod Senior Member Join Date: May 2003 Location: Deltona, FL Posts: 1,031 iTrader: 0 / 0% Rep Power: 24	just as a heads up.... TITAN MOTORSPORTS, which is local to me, charge 95 an hour if you tune it, and 145 an hour if they tune it. they said between 1 and 2 hours to tune my NA vehicle. __________________ Power is nothing without Control.

06-25-2004, 10:36 AM	#44
StyleTEG Senior Member Join Date: Oct 2003 Posts: 217 iTrader: 0 / 0% Rep Power: 15	I agree that its not something you HAVE to do, its an option that some might take and not others. But to make outrageous claims, or speculate on the difference in dyno time, or performance, doesn't benifit anyone. __________________ <a href=\'http://www.limitedslipmotorsports.com\' target=\'_blank\'>http://www.limitedslipmotorsports.com</a>

06-25-2004, 11:07 AM	#45
radnulb Senior Member Join Date: Sep 2003 Location: Sinsinnaty, Ohio Posts: 674 iTrader: 0 / 0% Rep Power: 19	Titan has done some good work... Familiar with the DIY tools not just Hondata too... __________________ PGMFI.org founder and DIY ECU tuning advocate Just say no to rice...

06-25-2004, 03:22 PM	#46
pissedoffsol RETIRED Join Date: Sep 2002 Location: Retirement Home Age: 29 Posts: 49,951 iTrader: 2 / 100% Ride: Electric Scooter Blog Entries: 1 Rep Power: 531	my tuner is 400 flat for pump gas, 500 flat for pump/race tunes. + dyno cost/hr at whatever shop you go to with him my local dyno is 100 first hr, 75 for 2nd, 50 thereafter. so if it takes 2 hours, its roughly 575-600 bucks for pump gas.

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