Air Intake tubes?
01-03-2005, 07:02 PM
#76
Nordschleife Master
Originally Posted by PorKen
GlenL,
I'm sorry, I missed/can't remember which car you tested on.
Could it be a calibration issue that caused the drop with the tubes removed? IE. too much, or too turbulent airflow for the air meter for the fuel injection system tested?
Did you get a mixture graph too?
(BTW, I'm not questioning your data, just curious.
)
I'm sorry, I missed/can't remember which car you tested on.
Could it be a calibration issue that caused the drop with the tubes removed? IE. too much, or too turbulent airflow for the air meter for the fuel injection system tested?
Did you get a mixture graph too?
(BTW, I'm not questioning your data, just curious.
)THe car is a 1980 Euro S (CIS).
Interesting questions. Made me re-open the graphs and take a look. I've attached a pic of the first, sizth and seventh runs. For runs 1-6 I was working on the mixture. Went real rich and then leaned it out. For the seventh run the only change was to replace the open element with the stock housing and tubes.
The real curious thing on the graph is that the last run shows a more lean condition than the preceding run. I've added the first run as that had about the same A/F ratio.
My take-away is the the housing resulted in a leaner run, but more power than the same A/F with no top.
Weird!
Last edited by GlenL; 07-13-2015 at 02:22 PM.
01-03-2005, 07:17 PM
#77
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yes, the 5 cubic feet thing was to make a point. was off by a factor of ^2. the point is, the air is moving so fast ,and there is very little relative volume in the tubes.
your HP gains or losses are hard to attribute to temps. Open filter, what type of filter, was it secured, did you have screens, etc etc.......... really. There are just as many folks that have seen 7hp with the open air box vs the tubes attached and the cover on. if i spent my dyno time trying to find the reason for 5hp losses or gains, you would go crazy. drop some holy water on your cars rear wing, and i bet you will see a 5 hp loss or gain, depending on if your car is possessed or not!!!!
Mk
your HP gains or losses are hard to attribute to temps. Open filter, what type of filter, was it secured, did you have screens, etc etc.......... really. There are just as many folks that have seen 7hp with the open air box vs the tubes attached and the cover on. if i spent my dyno time trying to find the reason for 5hp losses or gains, you would go crazy. drop some holy water on your cars rear wing, and i bet you will see a 5 hp loss or gain, depending on if your car is possessed or not!!!!
Mk
Originally Posted by GlenL
Mark (and all)
Couple of things:
I measured 5hp _more_ with tubes than the open filter. That is, even with any drop, the heat difference (lower) provided 5hp more. How else to explain it?
5 cubic feet of air is a rectangle 5 feet by 1 foot by 1 foot. (not 5x5x5)
Lemme see...
Lower temps good. Higher temps bad. Free-flowing good. Restriction bad.
One thing to remember is that the intake system is restricted at several places. The tube diameter, even at the venturi, easily provides enough flow for the throttle and valves. Easy calculations to make. Looks like Porsche did.
As for improving power, seems like Pappy (et al?) are onto something. Get a cooler charge into the cylinder. Now is it cost effective and reliable?
Couple of things:
I measured 5hp _more_ with tubes than the open filter. That is, even with any drop, the heat difference (lower) provided 5hp more. How else to explain it?
5 cubic feet of air is a rectangle 5 feet by 1 foot by 1 foot. (not 5x5x5)
Lemme see...
Lower temps good. Higher temps bad. Free-flowing good. Restriction bad.
One thing to remember is that the intake system is restricted at several places. The tube diameter, even at the venturi, easily provides enough flow for the throttle and valves. Easy calculations to make. Looks like Porsche did.
As for improving power, seems like Pappy (et al?) are onto something. Get a cooler charge into the cylinder. Now is it cost effective and reliable?
01-03-2005, 07:27 PM
#78
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you first have too lean of a mixture. dont look at the peak mixtures, look at the averages. the averages are in the 13's :1, period. next, look at the time between runs. two are 5 min apart and the other is 1/2 hour.
also look how you stap the throttle, you should do all the tests/runs the same as all sorts of variables are present when you dont. start at 3k for example. squeeze the throttle the same and let'er rip!! those ramp ups sometimes determine mixture for the entire run. also , engine temp, water temp. not to metion different clamp down orientation and levels of the chassis on day to day dyno comparisons. lots to control. be happy that your car is in the 250hp range and forget about the differences in the air box. we already know that there is no way that your going to see a difference from temps from the tubes even though we know that the temps could be lower in the tubes. how much lower?? maybe 20 degrees or 3hp. but, you are seeing more. flow efficiencies???? so many variables, so little time!
Mk
also look how you stap the throttle, you should do all the tests/runs the same as all sorts of variables are present when you dont. start at 3k for example. squeeze the throttle the same and let'er rip!! those ramp ups sometimes determine mixture for the entire run. also , engine temp, water temp. not to metion different clamp down orientation and levels of the chassis on day to day dyno comparisons. lots to control. be happy that your car is in the 250hp range and forget about the differences in the air box. we already know that there is no way that your going to see a difference from temps from the tubes even though we know that the temps could be lower in the tubes. how much lower?? maybe 20 degrees or 3hp. but, you are seeing more. flow efficiencies???? so many variables, so little time!
Mk
Originally Posted by GlenL
Ken,
THe car is a 1980 Euro S (CIS).
Interesting questions. Made me re-open the graphs and take a look. I've attached a pic of the first, sizth and seventh runs. For runs 1-6 I was working on the mixture. Went real rich and then leaned it out. For the seventh run the only change was to replace the open element with the stock housing and tubes.
The real curious thing on the graph is that the last run shows a more lean condition than the preceding run. I've added the first run as that had about the same A/F ratio.
My take-away is the the housing resulted in a leaner run, but more power than the same A/F with no top.
Weird!
THe car is a 1980 Euro S (CIS).
Interesting questions. Made me re-open the graphs and take a look. I've attached a pic of the first, sizth and seventh runs. For runs 1-6 I was working on the mixture. Went real rich and then leaned it out. For the seventh run the only change was to replace the open element with the stock housing and tubes.
The real curious thing on the graph is that the last run shows a more lean condition than the preceding run. I've added the first run as that had about the same A/F ratio.
My take-away is the the housing resulted in a leaner run, but more power than the same A/F with no top.
Weird!
01-03-2005, 07:33 PM
#79
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had this discussion w/mark T recently regarding strokers... mr dyno seems to show that the stock tubes flow fine, even for a stroker's increased needs - the box can help up to 8hp w/some tweaks (vel stack, bigger filter,ott's mods,etc), but that's bout it...
was kinda wondering why I'd need much hp at all sitting in traffic (unless I wanted to drown out britney spears next to me w/a raging burnout)... LA traffic is a bugger, does make that rare open road seem that much sweeter when we finally get a taste...
was kinda wondering why I'd need much hp at all sitting in traffic (unless I wanted to drown out britney spears next to me w/a raging burnout)... LA traffic is a bugger, does make that rare open road seem that much sweeter when we finally get a taste...
01-03-2005, 07:58 PM
#80
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Originally Posted by mark kibort
I dont usually race from idle oneward, usually, we rev the engines up for a seocond or so and then launch. this would clear ALL hot air from the tubes and you would be left what i have described, a slow heat transfer from the associated intake components. i have no mods done to the car except the headers, exhaust and intake air box vents with brake duct tubes (and the air box is sealed with cauking as well) "launching like a rabbit" , this means more hp, agreed, and we have not seen any of this on the dyno with a hot intake or cold intake. keep in mind, even if you could reduce the temps (actual intake charge) by 20f degrees, is only about 3hp!!! you CANNOT feel this!!
Now your testing me with a question about intercoolers? You may know this, but the idea of a intercooler is all about heat transfer. with air moving through vains (think radiator for cooling water) but much larger, but longer, the air moves through a air radiator to lower the temps. it has a much longer resident time as the molecules release their heat into the aluminum fin'ed box to release into the atomosphere. the main reason to use this is not for NA engines, but for turbocharged engines where the delta T is Tremendous. turbos/superchargers compress air, for which heat is generated (PV/NRT)
some of the turbos get air up to 300 degrees F. it takes an intercooler to bring temps with ambient flow through it, to down to 200 or even 150 degrees. This is not only a way to gain hp , but a way to keep from detonation. (dual gain) the more you reduce temps, the greater the hp will be. but we are talking 100 to 200 degree temp drops. on a NA car, the 1psi drop across a common intercooler will negate ANY gains of temp reduction. this is why intercoolers are not used on NA cars!!! cold air intakes are used, but our cars are already being fed by cold air to begin with. NOT to belabor the point again, but the resident time the air takes at WOT or even 4000rpm is not long enough to heat the air much after the tubes and intake plenum volume has been cleared ( 1/10 of a second)
any gains of "cooler" air off the line, is preceived and will not even show up at the dyno. if it does, its in the 2-3hp range, and this is insignificant.
If you want to have the effects of ram air at 200mph (ie approx .7psi gain) standing still, you should seriously consider the eRAM. it removes the restriction of stock air boxes and gains .5 psi on top of that for a 1psi net gain in pressure. its an axial flow device that can move 1000cfm at 26,000rpm through a 3.5" opening. (and belt out 3.5lbs of static thrust) the gains of this would far exceed anything you could produce in trying to cool the air with insulation tubes, vents , etc.
check out www.electricsupercharger.com
Mk
Now your testing me with a question about intercoolers? You may know this, but the idea of a intercooler is all about heat transfer. with air moving through vains (think radiator for cooling water) but much larger, but longer, the air moves through a air radiator to lower the temps. it has a much longer resident time as the molecules release their heat into the aluminum fin'ed box to release into the atomosphere. the main reason to use this is not for NA engines, but for turbocharged engines where the delta T is Tremendous. turbos/superchargers compress air, for which heat is generated (PV/NRT)
some of the turbos get air up to 300 degrees F. it takes an intercooler to bring temps with ambient flow through it, to down to 200 or even 150 degrees. This is not only a way to gain hp , but a way to keep from detonation. (dual gain) the more you reduce temps, the greater the hp will be. but we are talking 100 to 200 degree temp drops. on a NA car, the 1psi drop across a common intercooler will negate ANY gains of temp reduction. this is why intercoolers are not used on NA cars!!! cold air intakes are used, but our cars are already being fed by cold air to begin with. NOT to belabor the point again, but the resident time the air takes at WOT or even 4000rpm is not long enough to heat the air much after the tubes and intake plenum volume has been cleared ( 1/10 of a second)
any gains of "cooler" air off the line, is preceived and will not even show up at the dyno. if it does, its in the 2-3hp range, and this is insignificant.
If you want to have the effects of ram air at 200mph (ie approx .7psi gain) standing still, you should seriously consider the eRAM. it removes the restriction of stock air boxes and gains .5 psi on top of that for a 1psi net gain in pressure. its an axial flow device that can move 1000cfm at 26,000rpm through a 3.5" opening. (and belt out 3.5lbs of static thrust) the gains of this would far exceed anything you could produce in trying to cool the air with insulation tubes, vents , etc.
check out www.electricsupercharger.com
Mk
What I'm really trying to do is recover a power loss which occurs during the heat soak at every traffic light. Your right, this will not show up on a dyno because air is already moving at fairly high velocities through the induction system during the test. It's one of those anomalies that I would like to fix. I'm going to try a few more things before the jury is out. What I wanted to locate was the source of hot air prior to the MAF. I was even considering opening the hood right over the air box and putting a scoop there (old picture). I will check out the eRam system. Very interesting.
01-03-2005, 08:03 PM
#81
Burning Brakes
If cold(er) air intake provides benefits, how about extending and routing the intake tubes forward and down to the grill area under the front bumper rather than adding a scoop? I'd be a little concerned about creating additional drag, decreasing throttle response, or generating some undesired wave effect but it seems like it would be worth a try.
Rick
Rick
01-03-2005, 08:30 PM
#82
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Originally Posted by JKelly
Pappy, have you measured the surface temperature, at idle or after driving around, of any components associated with air flow intake? MAF, Throttle body, air box, intake tubes, plenum, the engine itself?...... Awhile back, I was messing around with my MAF after some in-town driving and it was so hot I couldn't touch it. That was AFTER air was passing through it.
If I was driving down the highway for 100 miles, it may have been cooler, along with the rest of the inline components...including the engine. But, the discussion is centered around in-town stop and go driving isn't it?
It would be interesting to know if there is a difference in intake air temperature just from insulating the top of the radiator (no other venting) so that the hot air created by engine heat wouldn't get sucked into the intake as easily.
It would also be interesting the know the overall difference in the engine temperature itself when running and/or idling with the hood scoop infront of the intake inlet and without ((does the hood scoop allow enough outside air into the intake tubes to actually lower the temp of the engine itself?)). If cooler air is constantly flowing through the intake, especially when idling, then the engine should constantly remain a little cooler; therefore, it should respond like it was a little cooler. Our cars are obviously sensitive to hot and cold air, so quick and easy access to outside air and the benefits it holds is plain common sense. The faster and more efficiently you can run cooler air through the 500 pound furnace under the hood, the better the potential for faster throttle response and more power at the wheels.
If I was driving down the highway for 100 miles, it may have been cooler, along with the rest of the inline components...including the engine. But, the discussion is centered around in-town stop and go driving isn't it?
It would be interesting to know if there is a difference in intake air temperature just from insulating the top of the radiator (no other venting) so that the hot air created by engine heat wouldn't get sucked into the intake as easily.
It would also be interesting the know the overall difference in the engine temperature itself when running and/or idling with the hood scoop infront of the intake inlet and without ((does the hood scoop allow enough outside air into the intake tubes to actually lower the temp of the engine itself?)). If cooler air is constantly flowing through the intake, especially when idling, then the engine should constantly remain a little cooler; therefore, it should respond like it was a little cooler. Our cars are obviously sensitive to hot and cold air, so quick and easy access to outside air and the benefits it holds is plain common sense. The faster and more efficiently you can run cooler air through the 500 pound furnace under the hood, the better the potential for faster throttle response and more power at the wheels.
Hello John,
Some of this will also be on my too do list. I did try insulating the top of the radiator with 1/4" modeling foam and then closed the hood. The air in the air box still rose to 150F, a bit cooler than without the foam. The problem is that the front of the radiator and AC condenser are still producing columns of rising hot air when the fans are not running. This allows a fair amount of heat to enter the intake tubes while the car is stopped. To gain enough room to install a duct the AC condenser would have to move or be removed. With the smoke test a fair amount of air is getting sucked into the nose scoop and into the air tubes because it is the lesser path of resistance. At speed this needs to be evaluated. Is most of the intake tube air coming from the nose vents, the nose scoop, both, or is air from the nose getting pushed back out the nose scoop making pressure drop???
01-03-2005, 08:35 PM
#83
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Id be careful hood scoops, as what you gain in coldness, may be lost do to that area of the hood could be in the low pressure range, (not high pressure range like the base of the windshield and nose)!! what you are really investigating is whether the heat soaked intake tubes are hurting hp. in my estimation based on their volume, and the feed area at one of the second best high pressure zones in front of the car, there would be marginal gains/losses at a stop light vs a hood scoop. you can always vent like the devek car, where it is sealed and there is a long opening that vents to the base of the windshield.
mk
mk
Originally Posted by pappy92651
Hello Mark,
What I'm really trying to do is recover a power loss which occurs during the heat soak at every traffic light. Your right, this will not show up on a dyno because air is already moving at fairly high velocities through the induction system during the test. It's one of those anomalies that I would like to fix. I'm going to try a few more things before the jury is out. What I wanted to locate was the source of hot air prior to the MAF. I was even considering opening the hood right over the air box and putting a scoop there (old picture). I will check out the eRam system. Very interesting.
What I'm really trying to do is recover a power loss which occurs during the heat soak at every traffic light. Your right, this will not show up on a dyno because air is already moving at fairly high velocities through the induction system during the test. It's one of those anomalies that I would like to fix. I'm going to try a few more things before the jury is out. What I wanted to locate was the source of hot air prior to the MAF. I was even considering opening the hood right over the air box and putting a scoop there (old picture). I will check out the eRam system. Very interesting.
01-03-2005, 08:35 PM
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Originally Posted by 928ntslow
So anyway, to answer the original question....
I replaced the tubes on both the 82 and 93 with stain/ heat resistant 3" flexable rubber venting hose. I got 6 foot lengths for each and cut to size. Cost per car was about $7.00. The ones on the 82 have been on for about a year now and they look as good as the ones I just put on the 93. They fit perfect, look perfect and though I have never dyno'd them, they work as well (if not better than) as the originals. Sucking sounds?...might be able to hear if the exhaust weren't so loud
Here are pics of both...
I replaced the tubes on both the 82 and 93 with stain/ heat resistant 3" flexable rubber venting hose. I got 6 foot lengths for each and cut to size. Cost per car was about $7.00. The ones on the 82 have been on for about a year now and they look as good as the ones I just put on the 93. They fit perfect, look perfect and though I have never dyno'd them, they work as well (if not better than) as the originals. Sucking sounds?...might be able to hear if the exhaust weren't so loud
Here are pics of both...
Nice air tubes (as you know the stock GTS tubes are about $150.00 a piece). Good fitment.
Last edited by pappy92651; 01-03-2005 at 08:53 PM.
01-03-2005, 08:50 PM
#85
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Originally Posted by rob rossitto
had this discussion w/mark T recently regarding strokers... mr dyno seems to show that the stock tubes flow fine, even for a stroker's increased needs - the box can help up to 8hp w/some tweaks (vel stack, bigger filter,ott's mods,etc), but that's bout it...
was kinda wondering why I'd need much hp at all sitting in traffic (unless I wanted to drown out britney spears next to me w/a raging burnout)... LA traffic is a bugger, does make that rare open road seem that much sweeter when we finally get a taste...
was kinda wondering why I'd need much hp at all sitting in traffic (unless I wanted to drown out britney spears next to me w/a raging burnout)... LA traffic is a bugger, does make that rare open road seem that much sweeter when we finally get a taste...
. The triple digit ticket paranoia is exceedingly high around here because we have laser traps all over the place. San Diego is even worse! No room to stretch the legs.
01-03-2005, 09:12 PM
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That's were all the fun starts, racing Corvettes light to light . The triple digit ticket paranoia is exceedingly high
been thinking about those fans too, as they do seem like they might solve that one in a jiffy... of course, NOS is something cool worth considering for those times that a stroker just isn't enough... 
01-03-2005, 09:18 PM
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Originally Posted by rjtw
If cold(er) air intake provides benefits, how about extending and routing the intake tubes forward and down to the grill area under the front bumper rather than adding a scoop? I'd be a little concerned about creating additional drag, decreasing throttle response, or generating some undesired wave effect but it seems like it would be worth a try.
Rick
Rick
This sort of thing has been done on race cars. You have to move or eliminate some things to make it work (like your AC). Not much room! This was done more to accommodate the throttle body positions as the stock air box could no longer be used.
01-03-2005, 09:53 PM
#88
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Again, for the Photoshop challenged... 
(I've got a spare hood, too, and I go back and forth on this idea, except with a big 'ol STI scoop.)
(I've got a spare hood, too, and I go back and forth on this idea, except with a big 'ol STI scoop.)
01-03-2005, 10:11 PM
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<Nice air tubes (as you know the stock GTS tubes are about $150.00 a piece). Good fitment.>
$150 a piece for new ones and they will still look like black turds rolled up a like taquitos. I took the originals and stowed 'em away. They are actually in very good condition, but the tubes I replaced them with, look just a wee bit more hi-tech. Thanks Pappy.
BTW, I absolutely urge you guys to keep "re-inventing the wheel"...one of these days, someone is going to make it rounder....and I mean that!
My biggest issue with all of this is a standing dyno with a fan blowing on the car. I just don't think one is going to get real world results in this fashion. There has to be another way.
$150 a piece for new ones and they will still look like black turds rolled up a like taquitos. I took the originals and stowed 'em away. They are actually in very good condition, but the tubes I replaced them with, look just a wee bit more hi-tech. Thanks Pappy.
BTW, I absolutely urge you guys to keep "re-inventing the wheel"...one of these days, someone is going to make it rounder....and I mean that!
My biggest issue with all of this is a standing dyno with a fan blowing on the car. I just don't think one is going to get real world results in this fashion. There has to be another way.
