Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.
Nashco wrote:Oh yeah, I also think it's a valid question to say, "If it's that good, why don't OEMs do it?" in a technical discussion.
True, and that is a GOOD question, but that's NOT the same as "It can't work because OEM's don't do it".
But that isn't what I said at all. I asked, in almost this exact way, if this technology is so good, helping in over half of the applications in every aspect of an engine's performance, without any negative affects, it would be highly desirable to car-makers. So why haven't any of them done it?
Then I hypothesized, that it was because it is an urban myth, like the tornado. You just up and deleted my post, despite it being civil, on topic, and completely reasonable.
Here is the part you missed from my earlier post
" The reason for the gains hasn't been isolated till now so I'm sure others will expand on the discovery".
This discovery is new! you wont read about it anywhere, I will explain the chamber groove improvement phenomena but I thought you guys might want to guess first. see the hint, "its generally a greater benefit on a V type engine". Also in my earlier post "the inefficiency that is the most interesting is that of a partially closed throttle".
Whipped talked about throttling losses in another thread and so I figure he may figure it out if he stays near this topic.
Atilla the fun may figure it out if he takes porting dynamic principles and applies them to throttling losses.
This is way to many clues now but I just want to end it before you all get bored.
Nashco wrote:Oh yeah, I also think it's a valid question to say, "If it's that good, why don't OEMs do it?" in a technical discussion.
True, and that is a GOOD question, but that's NOT the same as "It can't work because OEM's don't do it".
But that isn't what I said at all. I asked, in almost this exact way, if this technology is so good, helping in over half of the applications in every aspect of an engine's performance, without any negative affects, it would be highly desirable to car-makers. So why haven't any of them done it?
Then I hypothesized, that it was because it is an urban myth, like the tornado. You just up and deleted my post, despite it being civil, on topic, and completely reasonable.
Here is the part you missed from my earlier post
" The reason for the gains hasn't been isolated till now so I'm sure others will expand on the discovery".
This discovery is new! you wont read about it anywhere, I will explain the chamber groove improvement phenomena but I thought you guys might want to guess first. see the hint, "its generally a greater benefit on a V type engine". Also in my earlier post "the inefficiency that is the most interesting is that of a partially closed throttle".
Whipped talked about throttling losses in another thread and so I figure he may figure it out if he stays near this topic.
Atilla the fun may figure it out if he takes porting dynamic principles and applies them to throttling losses.
This is way to many clues now but I just want to end it before you all get bored.
To keep the fuel suspended in the intake charge, bla bla bla.
As an aerodynamicist, I think it's mostly bunk. A crap-shoot in the EXTREMELY complex flow that's happening when it's about to blow.
bigblockfiero wrote:
This discovery is new! you wont read about it anywhere, I will explain the chamber groove improvement phenomena but I thought you guys might want to guess first. see the hint, "its generally a greater benefit on a V type engine". Also in my earlier post "the inefficiency that is the most interesting is that of a partially closed throttle".
If its new then how did I read about it in Popular Science 4 years ago?
Oh yeah here's a tbricks thread that's been going on for a few years now: http://forums.turbobricks.com/showthread.php?t=66779 lots of people trying various grooves and reporting their results.. plenty of pics too. Overall a good read.
bigblockfiero wrote:
This discovery is new! you wont read about it anywhere, I will explain the chamber groove improvement phenomena but I thought you guys might want to guess first. see the hint, "its generally a greater benefit on a V type engine". Also in my earlier post "the inefficiency that is the most interesting is that of a partially closed throttle".
If its new then how did I read about it in Popular Science 4 years ago?
Oh yeah here's a tbricks thread that's been going on for a few years now: http://forums.turbobricks.com/showthread.php?t=66779 lots of people trying various grooves and reporting their results.. plenty of pics too. Overall a good read.
Good stuff. One of these days I'll have a chance to read it.
Bore out a hole in the head, put a fiber-optic lens in it, and hook it up to a high-speed camera. Run the engine and check out the before and afters at a consistant RPM.
If it's doing anything, it'll show up.
So, anyone want to volunteer an engine, and a $60,000 high-speed camera? :salute:
"Oh, this is too good. She thinks you're a servant... Cause you're black! This is greatest moment in my miserable life... Sooo-ey! I LOVE RACISM!"
Series8217 wrote:lots of people trying various grooves and reporting their results..
hah. But no numbers. I skimmed maybe 10 pages of that thread, and at best was a before dyno of 105 and after of 140....... with grooves and other mods added inbetween!
Seems to me that it'd be a total crapshoot either way--even if you could produce consistant "jets" of fuel/air, you'd have to be reasonably certain where to AIM them...
Even better, these "flat spots" you'd have to shoot for will change depending on throttle position, engine RPM, altitude, temperature etc etc etc...
The results aren't anywhere near consistent enough to argue successfully for.
That they work on a Briggs+Straton on a bench is great--it really is--but you can't reasonably make the case for it being worth it in a passenger vehicle application with staggeringly wide operating variants and conditions.
"Oh, this is too good. She thinks you're a servant... Cause you're black! This is greatest moment in my miserable life... Sooo-ey! I LOVE RACISM!"
The test engine is rather several test engines, all with different custom chamber shapes but any way, dont go posting this info all over the place quite yet till my story is complete, so heres the deal -----------
On a V type engine there is generally a centraly located carborator witch causes the short turn radius of the intake valves to be located on the inbord side (carborator side) of the cylinders.
Under part throttle conditions all the intake flow follows the short turn radious only, of the intake valves right to the squish pad area of the combustion chambers. Very little fresh mixture is in the cylinders at this point and the rest is all exhaust residuals. The squish pads of a V type engine are generally located on the inbord side of the cylinders and inbord of the intake valves.
The spark plugs on a V type engine are generally located on the outboard side of the cylinders for simplicity. As a piston is coming up on a compression stroke under part throttle, the fresh mixture is parthest from the spark plugs making it less able to efficiently light off the combustion event. Even just one (intake valve side) quench chamber groove aimed tward the plug has a noticable improvement of moving combustable mixture where it is needed most, near the spark plugs. So you see it dosn't matter how many grooves or the exact design just so long as that fresh mixture is moved tward the plugs to improve the combustion event.
So now you can see why a dyno will not show any gains even tho everybody can feel a noticable improvement. As soon as you open the throttle under more load then the intake flow travels to the long turn radius at mid stroke and so fresh mixture is then located on the spark plug side of the chambers and the combustion event is more efficient.
The only time open throttle improvements can be meashured is when you make a lugging comparison, that is a low rpm (below peak torque) such that the port velocity and piston speed is so low that the flow follows the short turn radius even tho the throttle is open.
Chamber grooves are a great improvement and there are several more interesting dynamics to take advantage of that I will describe latter, So anyway now you see why I say that the cause for the improvements has now been isolated and now that we know this we can expand on it.
bigblockfiero wrote:So now you can see why a dyno will not show any gains even tho everybody can feel a noticable improvement.
Uh....you can dyno an engine at less than WOT. This is how you develop fuel efficiency, power, etc. in an engine (along with many other things) and go through the iterative design process when building/refining an engine. Strap the thing to a dyno and run through a cycle of throttle position, load, RPM, temps, etc. and measure your air/fuel flow throughout all of the testing. You then use that data to compare multiple configurations (hardware, tuning, etc.) and develop the engine as your requirements demand.
So, to say that this won't show up on a dyno but it does improve something is nonsense. If it won't show up on a dyno, it isn't any different...a dyno is a load just the same as the road is.
bigblockfiero wrote:So now you can see why a dyno will not show any gains even tho everybody can feel a noticable improvement.
Uh....you can dyno an engine at less than WOT. This is how you develop fuel efficiency, power, etc. in an engine (along with many other things) and go through the iterative design process when building/refining an engine. Strap the thing to a dyno and run through a cycle of throttle position, load, RPM, temps, etc. and measure your air/fuel flow throughout all of the testing. You then use that data to compare multiple configurations (hardware, tuning, etc.) and develop the engine as your requirements demand.
So, to say that this won't show up on a dyno but it does improve something is nonsense. If it won't show up on a dyno, it isn't any different...a dyno is a load just the same as the road is.
Bryce
What I ment to say is that you cant see the improvement on a dyno the way that it is traditionally done, at wide open throttle, and in fact this is what I said in my first post of this thread----------
I am now making enertia dyno pulls at a steady eight inches of murcury (part trottle) up to eight grand and the improovement results are noticable and undeniably real.
For starters, ANY fuel/air is going to be forced towards the plug as the cylinder is moving up--there's nowhere else for it to go.
:scratch:
If you were to pull a perfect vacuum on an engines cylinder such that it has no air mass then quickly swing the piston up to TDC then down again, would it produce squish velocity?
You aren't talking about behavior of a vacuum; you're talking about a fuel-air charge that has mass and takes up space. Just because the manifold pressure is less than ambient doesn't mean that it's any more or less shoved around by the motion of the piston.
In the quench area, there is nowhere for the fuel/air to go except away towards the combustion chamber; there's no magic wall retaining it.
"Oh, this is too good. She thinks you're a servant... Cause you're black! This is greatest moment in my miserable life... Sooo-ey! I LOVE RACISM!"
bigblockfiero wrote:So now you can see why a dyno will not show any gains even tho everybody can feel a noticable improvement.
Uh....you can dyno an engine at less than WOT. This is how you develop fuel efficiency, power, etc. in an engine (along with many other things) and go through the iterative design process when building/refining an engine. Strap the thing to a dyno and run through a cycle of throttle position, load, RPM, temps, etc. and measure your air/fuel flow throughout all of the testing. You then use that data to compare multiple configurations (hardware, tuning, etc.) and develop the engine as your requirements demand.
So, to say that this won't show up on a dyno but it does improve something is nonsense. If it won't show up on a dyno, it isn't any different...a dyno is a load just the same as the road is.
Bryce
What I ment to say is that you cant see the improvement on a dyno the way that it is traditionally done, at wide open throttle, and in fact this is what I said in my first post of this thread----------
I am now making enertia dyno pulls at a steady eight inches of murcury (part trottle) up to eight grand and the improovement results are noticable and undeniably real.
Mach10 wrote:You aren't talking about behavior of a vacuum; you're talking about a fuel-air charge that has mass and takes up space. Just because the manifold pressure is less than ambient doesn't mean that it's any more or less shoved around by the motion of the piston.
In the quench area, there is nowhere for the fuel/air to go except away towards the combustion chamber; there's no magic wall retaining it.
Where I was going with that is to say that the squish velocity is less under say 15" of vacuum as compared to an engine at full throttle and maximum VE. The quench groove is then what a reflective cone is to a flash light, It focuses the velocity directly tward the plug.
So what your saying is that it does that anyway and I'm saying it does it much better and even while under a high vacuum condition to the point that it runs noticably better now, even with a big cam, and I have a strong steady idle even at only 500rpms.
bigblockfiero wrote:So now you can see why a dyno will not show any gains even tho everybody can feel a noticable improvement.
Uh....you can dyno an engine at less than WOT. This is how you develop fuel efficiency, power, etc. in an engine (along with many other things) and go through the iterative design process when building/refining an engine. Strap the thing to a dyno and run through a cycle of throttle position, load, RPM, temps, etc. and measure your air/fuel flow throughout all of the testing. You then use that data to compare multiple configurations (hardware, tuning, etc.) and develop the engine as your requirements demand.
So, to say that this won't show up on a dyno but it does improve something is nonsense. If it won't show up on a dyno, it isn't any different...a dyno is a load just the same as the road is.
Bryce
What I ment to say is that you cant see the improvement on a dyno the way that it is traditionally done, at wide open throttle, and in fact this is what I said in my first post of this thread----------
I am now making enertia dyno pulls at a steady eight inches of murcury (part trottle) up to eight grand and the improovement results are noticable and undeniably real.
What is an enertia dyno?
The engine spins a 280lb wheel that has one small magnet on it that spins by a sensor and produces an autible beep for each revolution.
These beeps are recorded and decifered by a program that produces a dyno sheet.
Or was your point that I spelled enertia wrong?
OK, INERTIA.
People keep making briggs and straton refrences and these chamber designs of mine are not that or anything that is publicly available but the irony is that quench chamber grooves were in fact tested by briggs under controlled labratory conditions, but not with a wedge chamber and only at full throttle.
If you have a V engine with inboard side plugs or an engine with a centraly located spark plug or an engine without a short turn quench area, then chamber grooves will not create as much or very much improvement.
The caddy motor in my fiero is a V-type with quench chamber grooves. I have a switch pitch torque converter, 1000rpm stall off and 2500rpm stall on. With the grooves the higher stall is no longer nessesary and the tires dont hit as hard on low stall so it doesn't spin wile street racing on cold crappy roads.
bigblockfiero wrote:
Or was your point that I spelled enertia wrong?
OK, INERTIA.
Haha...
bigblockfiero wrote: This system was so succesfull that vorticies could be seen within a cylinder and the onset of plug wetting could be manipulated by putting in a dished valve to push the vorticy away from the plug or laying back a chamber wall to prevent the vorticy from occuring in the first place.
Not bashing you, man, just helping out. :thumbleft:
bigblockfiero wrote:If you have a V engine with inboard side plugs or an engine with a centraly located spark plug or an engine without a short turn quench area, then chamber grooves will not create as much or very much improvement.
The caddy motor in my fiero is a V-type with quench chamber grooves. I have a switch pitch torque converter, 1000rpm stall off and 2500rpm stall on. With the grooves the higher stall is no longer nessesary and the tires dont hit as hard on low stall so it doesn't spin wile street racing on cold crappy roads.
Don't forget that there is a Caddy engine that does have centrally located plugs...
