IHADAV8.com - Turbo Buick Tech, and Nonsense
General => For Sale/Trade/Want To Buy => Topic started by: ttipe on October 25 2013, 11:34:20 PM
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WTB
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send me your address and I will mail one to you
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What is it about the Hemco that makes them so noteworthy? Is it marketing or do they do something better that I don't know about?
I've never put my hands on one but it seem like it's basically an elbow more so than a plenum.
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Steve if you serious about sending me one my address is
WAYNE SHERMAN
27436 POND DR.
NEW HUDSON MICH.
48165
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Earl the power plate creates a significant and unecessary back pressure (2 to 3 psi) across the compressor. The Hemco (properly prepared will distribute air evenly without the back pressure. Several well known names in the community use them and are running 9's with their street cars. Are you still re working GM front covers??
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if I can find it, I will send it out next week...finding may be harder than shipping smh
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Hey Steve thanks for looking whether you find it or not.
Wayne
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No problem...I should have a couple of uppers-one being a hemco...just have to figure out where they are...I need an organizer
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Earl the power plate creates a significant and unecessary back pressure (2 to 3 psi) across the compressor. The Hemco (properly prepared will distribute air evenly without the back pressure. Several well known names in the community use them and are running 9's with their street cars. Are you still re working GM front covers??
I understand that it's supposed to even out the flow to all cylinders, but from what I understand it really doesn't. Seems like it's one of those things that look like it will flow "X" ways, but in actuality, doesn't. From what I recall from seeing a picture of one years ago, it had a square discharge right in the middle of the plenum opening. A side effect was losing plenum volume, which I am against.
The reason I asked if it was more of a marketing thing is because I'm working with a foundry/CNC shop to start making upper plenums. My main goal is more plenum volume with the stock architecture with the side effect of not needing the powerplate.
Yeah, I still play with oil pumps from time to time. :)
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The Power Plate works quite well when comes to evening distribution. This has been shown by six egt sensors in before and after tests. It also helps one run closer to the edge tuning wise.
But, there comes a point somewhere in the high nines where it can become a hindrance because it redistributes air flow by restricting flow to the back cylinders and forcing it to go elsewhere.
I had not thought of Wayne's point about back pressure on the compressor but it is obvious when I think about it. Typically, we measure boost in the plenum and the major restriction between the turbo and the plenum is the IC so that we may have 28 psi at the turbo outlet and 26 in the plenum...but what really matters is the amount of air going into the cylinders and thus the PP restriction might further limit the flow so that our 26 is higher than what is going down the lower intake...not saying that boost is important but the flow is and the turbo efficiency of a non alky car becomes more critical
Normal cars probably don't see this as significant but a really strong one easily could.
Earl, plenum height gets dicey fast as the hood gets in the way right at the height of the PTE
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oh, yeah, I found the Hemco just as I was about to give up :)
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Yeah, I can't go up too much. Not any higher than the vacuum block that is. Plenty of room to the PS but the DS has to contend with throttle bracket and I don't want to reinvent the wheel there. Oh, and can't go too far forward because of IAC/MAF pipe clearance... So I've been getting creative trying to increase volume, keep from having to replace the nearby componets, and increase flow distribution.
I wish there was room to move the TB forward. Then it would be easy easy to do some cool stuff.
If you get bored snap a few pics of that hemco before you mail it off.
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this used to be on my site http://www.vortexbuicks-etc.com/plenum_comparison.htm (http://www.vortexbuicks-etc.com/plenum_comparison.htm)
I guess I decided it was obsolete and it is not linked anymore to the index
Does that help, or do you want more?
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Steve any data/imfo that you have usually has value.
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with me, data/info and opinion are often pretty close to one another LOL
I guess these things have become rare. I am glad I did not throw it away. Hopefully it will serve you well. I think it is probably the 58 mm version but I am sure you can enlarge it when you polish it up inside
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That's where I remember the picture from years ago. I wonder how a stock plenum would work with a hemco shaped plate under it. Basicaly the same sized rectangle as the hemco under the plenum. I have a feeling it would work like the hemco only with retaining some plenum volume(ish).
Thanks Steve. I remembered correctly. The Hemco is basically an elbow that dumps into the mental of the manifold. Different direction that where I was going with my plenum design(s).
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The Radius Kid and I spent about 3 hrs talking with Red A. about "stuff". The Hemco came up in conversation. He basically drops the "F" bomb on the power plate. He uses the stock appearing hemco in his tse car. He was showing John and I around. There appeared to be no spacer.Red's car went 9.17 @ 148. An interesting tidbit, on cyls 1 thru 4 1.65 rockers, cyls 5 & 6 1.6. Several others are running a Hemco as well. Some have external engine management (XFI for example) or use XFI to alter their calibration. Red's guys use XFI to alter a file and then load the VE and spark tables in a chip. Dave Poppe is one of those. He goes nines. My goal is to run well on pump gas??? I have ported GN1's and a new engine on the stand.
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I remember when Bamford went low nines with a PP. I am getting old and don't remember if he was running a PTE upper or what, tho :)
I remember reading this long ago http://www.hemcomachine.com/articles/article3.htm (http://www.hemcomachine.com/articles/article3.htm)
too bad that we never see much serious science on Buicks. Be interesting to see some flow bench results. I would like to see both wet and dry flows given that so many of us spray alky into the up pipe
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That's where I remember the picture from years ago. I wonder how a stock plenum would work with a hemco shaped plate under it. Basicaly the same sized rectangle as the hemco under the plenum. I have a feeling it would work like the hemco only with retaining some plenum volume(ish).
Thanks Steve. I remembered correctly. The Hemco is basically an elbow that dumps into the mental of the manifold. Different direction that where I was going with my plenum design(s).
I think you would get a lot of disruption and distortion of the flow due to the edge affect of the plate. Maybe a cast insert into the upper would provide better direction?
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Steve how much do I owe you for the Hemco and shipping? I'm hoping to make a flow core from the casting and see if our suspicions are confirmed. Talking about airflow (fluid dynamics) on a board is tough.Please observe that most of the hemco users that I know of (except the Tinman) are using external engine management (xfi,bs3 etc) systems which are controlling 6 one cylinder VE and Spark tables with about a 20% positive tolerance. The gain is the back pressure reduction across the compressor hot side. In my case I have ported Champ GN1's (better plug placement in chamber for faster burn; less octane req'd; relocated larger valves for "unshrouding" and the illustrious additional heat loss through the aluminum) along with a TA61 that "radius" worked like extrude hone for both compressor and turbine (about 10% volume flow increase-it screams like an F1 turbo when asked), PTE slic with improved scoop which helps to utilize the core surface area and xfi. Other stuff is part of this but I don't have the additional time at present. The goal is an 11 sec reliable pump gas (93 octane) T Type. The backpressure reduction across the compressor gradient will get me closer to the efficiency island of a 60-1 compressor wheel.
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it's on the house...I never sell parts :)
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and, it's a 65mm
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Hey Steve thanks again so much for your generosity. If you have any further info, data or opinions please send them your input is valued. There is a lot of conflicting data/opinions from varying sources which is to be expected. The goal is back pressure /boost reduction and reduced knock tendencies. People celebrate running large boost numbers or lots of back pressure??? I may be able to bring some FEA tools into this. You will be the first to know about what we're doing and what we find out. When Radius and I went on this year's road trip we agreed to attempt a science based inquiry into the problem and any possible fix.
Thanks Again
Wayne Sherman
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Sounds like you are trying to go the right direction. Technically, you are way of ahead of me these days because I have not been paying much attention.
If I were trying to do this, I would do anything I could to the heads to promote a consistent flame front and to help offset the thermal inefficiencies of the heads, I would think about some thermal coatings to retain heat in the chamber in a controlled manner as well as in the ports. Also on the inside of the pistons...mayb e a dispersant. Anything to even out hot spots.
I would look at over driving a high volume water pump to increase pressure in the block to try to alleviate any potential steam points.
I would look at compression in the 9.5-1 range to go away with a longer duration cam to keep the dynamic cylinder pressures down at lower rpms.
I would try to figure out the sweet spot of the ported turbo with regard to efficiency in order to push the most molecules possible into the cylinder and I would start with a low timing in the 16 deg range and not be surprised if optimum timing was no more than 18 degs.
I would also try to keep a narrow rpm band to simplify both fueling and timing and consider trying to use four gears instead of three in order to be able to keep the rpm band narrow to avoid having to twist the engine too hard as well as take some load off the turbo's air flow.
It's going to be all about controlling combustion chamber heat all the way to the turbo. Might be time to look at downpipe design to try to avoid some of the backpressure problems by allowing very rapid expansion to cool the temp on the outlet side.
biggest air filter you can stick on the front of the turbo and a means of getting cool air to it...
Maybe a looser than normally required converter to get the turbo going without having to drive it by loading the engine to get enuf heat to get it going at lower rpm to give you more margin on the rest of the run so you could tune for top end without being penalized by the launch-heatwise
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I'm sorry Steve I've been readin this post and can't come to a conclusion on what your opinion is on the rjc pp in regards to a stock plenum. So would you recommend the pp with a stock plenum?
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yes...without hesitation. However, unless you are tuning close to the edge for maximum performance, you may never know it's there :)
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Thanks Steve :)
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In this thread, we were discussing a scenario where the PP may impede the amount of air required to run down in the nines and/or a special case where he is trying to run elevens on straight pump gas with no alky, etc.
I am not sure the PP will interfere with that goal but this is an abnormal situation where it is desired to absolutely maximize all parameters so every possibility is being explored. Consider it to be a science project :)
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Very helpful information. Thanks for the insight. :)
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Steve just a couple of observations. It looks possible that folks could have been using a Hemco with a lower intake egr chimney whether functional or not. This may cause poor air flow to the front cylinders ,uneven egr distribution or both where egr was not disabled mechanically and in the software. If things can look ok on pump gas (depending on consistent octane) things may look better on race gas.
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could well be. it should be there tomorrow but I never believe the PO anymore :)
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I updated my combo in my profile.
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Interesting stuff going on. There is a post on the "other board" I believe in the general section titled "interesting numbers". Richard Clark was flowing different intake manifold / plenum combos. They were using some science in their approach. They flowed a Hemco and it did very well. I don't know whether you venture over there or not but the results are very interesting, not conclusive but some ideas are coming to light. I'll chime in tomorrow with specifics that I thought after you have had an opportunity to see for yourself.
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no, I never bother going over there ;)
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Found them....looks like the PP does what it is supposed to and would be good on the average car. The Hemco flows a bit more and also does a good job. Given the upside on really fast cars, someone needs to start casting them again :)
More interesting to me was the upside potential of the intakes themselves-again for really fast cars
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There is a 9 cfm gap between 2 & 4. If I can reduce that gap by 4/5 cfm that will make my day (based on their testing). I asked if they flowed it with the egr tower in/out. If the tower was in that could fix my concern.
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Hemco being gently worked. Lower being equalized. I did play around with all these findings from Richard Clark and #2 needs flow improvement. Do I believe my findings. No Way! Too much variability with the work of others. The proper way is to balance the manifolds (upper & lower ) as a system. Lots of data and long story. For building a pump gas only car equalizing the intake is definately a plus.
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some times, one must find the answer and then create the theory
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some times, one must find the answer and then create the theory
Sounds like you found hardcore religion! :D
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I cannot argue against that