The Mother Of Air Box mods?
07-06-2003, 05:14 PM
#1
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The Mother Of Air Box mods?
My car felt starved. I would put the hammer down and it would go a bit, then go a bit less, until it 'cammed' in at around 3000rpm. (Especially in hot weather.)
I tried 3" hoses all the way to the fog lights (see here), and the initial takeoff was improved, but it slackened off fast; because of all the bends required, I figured.
Then for kicks, I left the tubes off. Hey, it actually made a difference!
Then I took the lid off. (yes, that's bungy-cord) Son-of-hibatchi, different car!
Which led to the MOAB, which
I spot welded together from 1/8" rod and 1/8"x1/2" bar:
(trusty used spot-welder)
Overall driveability has improved markedly.
My testing was all on 80-90f outside temps so I'm no longer a believer in the theory that the intake tubes pull significantly colder air in.
Of course YMMV; my [US '81 L-Jet 4.5L automatic] has a K&N air filter (from PO), 3" exhaust, with a Flowmaster Delta 50 in place of the cat, no vacuum connections except the brake booster and heater system, no mechanical fan, no air pump, no A/C. Timing is 33@3000. I'm guessing the car weighs < 3200lbs now.
I will be revising this design and using aluminum next.
FYI: the K&N breather is part#62-1420 (1" flange, 3" wide, 2" tall, ~$16) and I drilled the oil cap internal restriction out to 1/2".
~thread~start~
I tried 3" hoses all the way to the fog lights (see here), and the initial takeoff was improved, but it slackened off fast; because of all the bends required, I figured.
Then for kicks, I left the tubes off. Hey, it actually made a difference!
Then I took the lid off. (yes, that's bungy-cord) Son-of-hibatchi, different car!
Which led to the MOAB, which
I spot welded together from 1/8" rod and 1/8"x1/2" bar:
(trusty used spot-welder)Overall driveability has improved markedly.
My testing was all on 80-90f outside temps so I'm no longer a believer in the theory that the intake tubes pull significantly colder air in.
Of course YMMV; my [US '81 L-Jet 4.5L automatic] has a K&N air filter (from PO), 3" exhaust, with a Flowmaster Delta 50 in place of the cat, no vacuum connections except the brake booster and heater system, no mechanical fan, no air pump, no A/C. Timing is 33@3000. I'm guessing the car weighs < 3200lbs now.
I will be revising this design and using aluminum next.
FYI: the K&N breather is part#62-1420 (1" flange, 3" wide, 2" tall, ~$16) and I drilled the oil cap internal restriction out to 1/2".
~thread~start~
Last edited by PorKen; 09-19-2003 at 02:38 PM.
07-06-2003, 05:26 PM
#2
Burning Brakes
The problem with this setup may be sucking in hot air (from over and around the engine) instead of relatively cooler air, from infront of the engine. Every engine tuner knows that hot induction air is less efficient than cooler induction air. YMMV.
07-06-2003, 05:36 PM
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As noted in italics, my 'testing' was done at 90 degree outside temps, with a notable improvement in takeoff, even in rush hour traffic.
My long term design goal has always been to install an aluminum sheet over the empty area in the hood, to duct a large quantity of cooler air from in front of the radiator.
I was truly surprised at the difference this unducted modification made, even, as I said, in stop-and-go driving. I am no longer certain that the ducting would be worth the effort, unless I seal the entry into the top of the airbox for a ram-air effect.
Of course, YMMV.
My long term design goal has always been to install an aluminum sheet over the empty area in the hood, to duct a large quantity of cooler air from in front of the radiator.
I was truly surprised at the difference this unducted modification made, even, as I said, in stop-and-go driving. I am no longer certain that the ducting would be worth the effort, unless I seal the entry into the top of the airbox for a ram-air effect.
Of course, YMMV.
Last edited by PorKen; 07-15-2003 at 12:19 AM.
07-06-2003, 05:45 PM
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The K&N came with the car, I had decided to buy the stock filter along with my next oil filter order, mostly because the K&N does not seem to fit properly. But more horses would be nice too!
Side note: I have a dim theory that without the upper fan shroud (which I don't have) that at speed, cool air flows over the top of the radiator and creates a high pressure area at the rear of the engine, as there is limited room for the air to escape quickly.
Side note: I have a dim theory that without the upper fan shroud (which I don't have) that at speed, cool air flows over the top of the radiator and creates a high pressure area at the rear of the engine, as there is limited room for the air to escape quickly.
Last edited by PorKen; 07-15-2003 at 12:19 AM.
07-06-2003, 06:00 PM
#6
Burning Brakes
The proff in the pudding (so to speak) is a dyno test with "before" and "after" results.
I don't know about yours, but my assometer is not as reliable as I thought it once was. ;^) YMMV.
I don't know about yours, but my assometer is not as reliable as I thought it once was. ;^) YMMV.
07-06-2003, 06:18 PM
#7
PorKen,
Nice experiment.
What are you topping out at now RPM wise?
Have you tried coming back down off of that advance?
I was thinking of fenderwell lip scoops to behind the front tire splash guards for a ducted cool air induction myself. There is plenty of room on both sides though the feed tubes would probably end up a little smaller.
Ernest,
At the risk of starting the K&N bash all over again, and yes, I read the last S/C update with Dyno results. Impressive, and well documented.
If you punch K&N into the old browser you will also find Dyno, particulate filtering, flow area discrepancies across the board. Pros and cons.
I flat out discount anyhing testifying to critter parts passing "THRU" the K&N.
I do, however, believe the accounts of hot-wire coating and oil pooling, though the latter has at
least one other avenue of entry with or without the K&N. Part of the coating problem is over saturation of the K&N and were I to own a sHARk with the hot-wire I WOULD NOT use the K&N.
I have used mine for around two years and believe if one carefully inspects the cover/filter area before removal , as well as insuring a tight seat when installing the K&N there will be no ingestion of bug parts, leaves, squirrels, etc...
BTW I have zero pooling.
The HP question is worthy of a look see, If it proves out I would agree to eventually swap back to a stock filter to (re)gain 3-5 'lost'HP.
Every little bit helps.
Nice experiment.
What are you topping out at now RPM wise?
Have you tried coming back down off of that advance?
I was thinking of fenderwell lip scoops to behind the front tire splash guards for a ducted cool air induction myself. There is plenty of room on both sides though the feed tubes would probably end up a little smaller.
Ernest,
At the risk of starting the K&N bash all over again, and yes, I read the last S/C update with Dyno results. Impressive, and well documented.
If you punch K&N into the old browser you will also find Dyno, particulate filtering, flow area discrepancies across the board. Pros and cons.
I flat out discount anyhing testifying to critter parts passing "THRU" the K&N.
I do, however, believe the accounts of hot-wire coating and oil pooling, though the latter has at
least one other avenue of entry with or without the K&N. Part of the coating problem is over saturation of the K&N and were I to own a sHARk with the hot-wire I WOULD NOT use the K&N.
I have used mine for around two years and believe if one carefully inspects the cover/filter area before removal , as well as insuring a tight seat when installing the K&N there will be no ingestion of bug parts, leaves, squirrels, etc...
BTW I have zero pooling.
The HP question is worthy of a look see, If it proves out I would agree to eventually swap back to a stock filter to (re)gain 3-5 'lost'HP.
Every little bit helps.
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07-06-2003, 06:47 PM
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Ed,
Have you had your assometer calibrated lately? Ask your doctor to do it with your next flexible sigmoidoscopy. There's a pucker factor adjustment also.
John,
Notwithstanding the buzzard gizzards and jackalope hearts, and apart from fricaseed MAFs, the K&N is just plain more restrictive to air flow than the stock filter.
Have you had your assometer calibrated lately? Ask your doctor to do it with your next flexible sigmoidoscopy. There's a pucker factor adjustment also.
John,
Notwithstanding the buzzard gizzards and jackalope hearts, and apart from fricaseed MAFs, the K&N is just plain more restrictive to air flow than the stock filter.
How are you doing with your transmission cooler? Do you have the part # for the metric fittings?
07-06-2003, 09:30 PM
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So, all it takes to get more HP is to remove the fan shroud, air filter box cover, and hoses? Thank god, finally somebody figured this out!
Those dumb Porsche engineers! They could have had is soo easy developing the next generation, more powerful 928 AND saving the company some money by eliminating all those unnecessary parts. Instead, they gave us more valves, more displacement, more electronics, and less emissions, but a higher price.
Now, I just wonder, if "reversing engineering" is the same as "reverse" engineering...
Those dumb Porsche engineers! They could have had is soo easy developing the next generation, more powerful 928 AND saving the company some money by eliminating all those unnecessary parts. Instead, they gave us more valves, more displacement, more electronics, and less emissions, but a higher price.
Now, I just wonder, if "reversing engineering" is the same as "reverse" engineering...
07-06-2003, 09:51 PM
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Nicole,
According to Porsche
“Exhaust gas recirculation causes higher fuel consumption and impairs
Performance.”
“The power required to drive the air pump reduces engine output and increases fuel consumption”.
“Additional components mean extra cost and complexity”
Yes the engineers were brilliant, but in order to comply with emission legislation they had no choice but to add these performance hindering components.
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According to Porsche
“Exhaust gas recirculation causes higher fuel consumption and impairs
Performance.”
“The power required to drive the air pump reduces engine output and increases fuel consumption”.
“Additional components mean extra cost and complexity”
Yes the engineers were brilliant, but in order to comply with emission legislation they had no choice but to add these performance hindering components.
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
07-06-2003, 10:47 PM
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I know that, Steve, but I for one am glad we have those emissions laws. We would not be able to breath anymore without them! If you have ever been in East Germany before the reunification, they you have experienced first hand why this is necessary. I don't have to drive far to see the brown air hovering over the SF Bay Area, and you can see it even worse in LA and probably Houston. As it mixes into the atmosphere, pollution affects all of us, all over the world.
Sure, it's not just cars causing this, but not having emissions reduction equipment, cars would be a much larger problem. I look forward to low sulfur diesel becoming available by 2005 and hope, that some day there will be a better way of blowing leaves than stinking 2-stroke engines (in Germany, we used to have brooms and rakes for that - and no, I did not ride on the brooms). Of course, powerplants and factories need to reduce emissions as well.
The fact that others do bad is no justification for me to do bad as well. I am more than happy to sacrifice 5 of 300+ hp for cleaner air. To me, health of myself and the people around me is worth more than a 10th of a second off a 0-60 run. Because if I'm not healthy I won't be able to do a 0-60 run in the first place.
And there are lots of ways of getting more power with emissions equipment in place - it just takes a little more effort. It's the difference between going the "quick and dirty" route, or doing it right (the way it should be done, given today's density of population and environmental issues).
My life is part of a bigger picture, not just a tiny little selfish one.
Now, let's go back to Ken's ingenious airbox modifications...
Sure, it's not just cars causing this, but not having emissions reduction equipment, cars would be a much larger problem. I look forward to low sulfur diesel becoming available by 2005 and hope, that some day there will be a better way of blowing leaves than stinking 2-stroke engines (in Germany, we used to have brooms and rakes for that - and no, I did not ride on the brooms). Of course, powerplants and factories need to reduce emissions as well.
The fact that others do bad is no justification for me to do bad as well. I am more than happy to sacrifice 5 of 300+ hp for cleaner air. To me, health of myself and the people around me is worth more than a 10th of a second off a 0-60 run. Because if I'm not healthy I won't be able to do a 0-60 run in the first place.
And there are lots of ways of getting more power with emissions equipment in place - it just takes a little more effort. It's the difference between going the "quick and dirty" route, or doing it right (the way it should be done, given today's density of population and environmental issues).
My life is part of a bigger picture, not just a tiny little selfish one.
Now, let's go back to Ken's ingenious airbox modifications...
07-06-2003, 11:02 PM
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John - with some difficulty I have been resisting going to take-off speeds, as I am a few parts shy of a high-torque TB conversion, and don't want to push my old belt too much. What I was so surprised by this project was the difference at low engine speeds. What advance do you recommend?
Steve - Too much time, yes. The rear trans cooler is still delivering the goods, no leaks no damage. I was comfortable enough to remove the factory hard lines from under the car, which cleaned up the underbody nicely. Which fittings?
Nicole - The Porsche engineers had more restrictions in their design process (especially in regards to the North American market) than I have. The air box, for example, is designed firstly for intake roar reduction, and secondly for actual air intake. Forget leaf blowers, in the unified Germany you have stinking noisy 2-stroke plastic Trabants, too!
On the subject of my own autos, I am selfish, inconsiderate, and uncaring of air quality or noise pollution (and now have a supercar sized ego
). I have only two design goals: make it Europeanly fast, and cover everything in leather.
Moreover, the more 'stuff' I take off, the more I can see of the real Teknik, vs. the mandated Zusätze!
Steve - Too much time, yes. The rear trans cooler is still delivering the goods, no leaks no damage. I was comfortable enough to remove the factory hard lines from under the car, which cleaned up the underbody nicely. Which fittings?
Nicole - The Porsche engineers had more restrictions in their design process (especially in regards to the North American market) than I have. The air box, for example, is designed firstly for intake roar reduction, and secondly for actual air intake. Forget leaf blowers, in the unified Germany you have stinking noisy 2-stroke plastic Trabants, too!
On the subject of my own autos, I am selfish, inconsiderate, and uncaring of air quality or noise pollution (and now have a supercar sized ego
). I have only two design goals: make it Europeanly fast, and cover everything in leather.Moreover, the more 'stuff' I take off, the more I can see of the real Teknik, vs. the mandated Zusätze!
Last edited by PorKen; 07-15-2003 at 12:29 AM.
07-06-2003, 11:31 PM
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Nicole,
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">My life is part of a bigger picture, not just a tiny little selfish one.
Wow that is heavy, in the 1800s a Native American sent a letter to the president at the time; he spoke of how we were killing mother earth. I can’t remember were I read it
Thank you for your perspective.
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">My life is part of a bigger picture, not just a tiny little selfish one.
Wow that is heavy, in the 1800s a Native American sent a letter to the president at the time; he spoke of how we were killing mother earth. I can’t remember were I read it
Thank you for your perspective.
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />