Air Diverter
#61
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Originally Posted by rob rossitto
just a thought, but if it's heat build up that's the enemy, would bigger fans help? ie just blast more air under there to keep the whole compartment cooler, and there would be less build up in front, hence cooler air for the intake tubes...
Yes, a change in the fan configuration would help. I don't think that bigger fans are required, instead a fan switch that triggers the fans at a lower temp. I have not been able to find anything that fits in the system. Any ideas?
The other factors are better cooling at speed and more air pressure to the air box. The diverter increases smooth air flow through the radiator at speed. My temp gauge is now reading below 1/2 at cruising speeds and is down around 3/8 at 100 MPH. The pressure gains from the hoses are however minimal. They serve better as a source for cold air. Without the diverter the turbulent air rolls around against the hood / radiator, picks up heat, and then enters the air tubes.
Yes, It's all about keeping it cool at all speeds.
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Originally Posted by pappy92651
Tony, I did it all with my Junghans precision stop watch. I will be buying a GTECH so that I might log data without the human error associated. When I hit third it feels like the drive train is going to come through the bottom of the car. Really strange to drive an AT 928 that lifts the nose in 3 gears. The car just squats and pulls. I'm taking bets on which rear axle will give up first (bet you know or will find out).
I have the GTECH RR with PASS software. A bit $$$ but well worth it. It has a great feature where you can email the GTECH files to one another and with the software be compared to your own car or others...Ive run mine agaisnt Ferraris..Vipers etc etc on the software.
Im not slamming you at all, but remember, a stop watch is only as accurate as the reaction time on the finger running it and the eyes scanning the rapidly rising speedo across 60mph. A least the GTECH is hands free and records everythign for you.
#63
pappy, you've done some really incredible research - automotive OEM quality stuff IMHO...
I picked up the devek aluminum "sale" shroud, dual 1300cfm spals, might put some extra vents w/rubber flaps in "dead" spots for extra flow/cooling at speed... was hoping they'd push more air than the mech stuff through the compartment at idle and keep air moving through the front too...not a lot of room for much else as you know/thought about louvers in the fender wells as a last resort, but your diverter seems like a clever way to further isolate the intakes...also did jet hot on the headers to keep temps down, but was advised NOT to use header wrap/although I suspect it would help a bit too...
funny thing about gtech vs dyno - my race bike wrench sold his dyno (al holley) cause it never seemed to be accurate when bikes were run in the 'real world'... something about varying loads and wind, rates of accel, etc... suspect there's a place for both, but I'd probably trust gtech type stuff more for a real world measurement on most airflow type mods...
have you experimented w/the ott velocity stack and his airbox mods (larger bottom section)? I've got one coming, so if you want to "borrow"/experiment/ck it out/etc till I need it, I can leave it at greg's for you... claims of 8hp and better throttle response on a stock (+/-) GT were made by PO who now runs a FI system...might be interesting w/your other mods...
I picked up the devek aluminum "sale" shroud, dual 1300cfm spals, might put some extra vents w/rubber flaps in "dead" spots for extra flow/cooling at speed... was hoping they'd push more air than the mech stuff through the compartment at idle and keep air moving through the front too...not a lot of room for much else as you know/thought about louvers in the fender wells as a last resort, but your diverter seems like a clever way to further isolate the intakes...also did jet hot on the headers to keep temps down, but was advised NOT to use header wrap/although I suspect it would help a bit too...
funny thing about gtech vs dyno - my race bike wrench sold his dyno (al holley) cause it never seemed to be accurate when bikes were run in the 'real world'... something about varying loads and wind, rates of accel, etc... suspect there's a place for both, but I'd probably trust gtech type stuff more for a real world measurement on most airflow type mods...
have you experimented w/the ott velocity stack and his airbox mods (larger bottom section)? I've got one coming, so if you want to "borrow"/experiment/ck it out/etc till I need it, I can leave it at greg's for you... claims of 8hp and better throttle response on a stock (+/-) GT were made by PO who now runs a FI system...might be interesting w/your other mods...
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Just thinking here... all very interesting stuff by the way... I certainly see the benefits for ducting cool/cold air. No problems there. Where I'm having difficulty is understanding how this will generate ANY positive air pressure (a la super charging). Somewhat akin to Wally post regarding stalled air after the radiator, wouldn't the same be true for the air filter? The only way you'd be able to ram-air the 928 is to completely seal the intake tubes, filter box, etc. If there were any holes or leaks in the system, you'd lose all the pressure benefits.
Am I wrong?
Since I don't see any attempt to seal the system, I think your goal should be going after cool air alone. This may give you some design freedom. Good luck.
Am I wrong?
Since I don't see any attempt to seal the system, I think your goal should be going after cool air alone. This may give you some design freedom. Good luck.
#65
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steve, i asked mark k about his airbox mod and you can see pics of it on his website. they have simply ducted air directly from the base of the windshield through the stock cavity there (with wiper motor etc) and into the airbox. i can remember a concern expressed about water ingestion but when i asked mark he admitted to having driven in the rain with no ill effect on at least one occasion when it was raining very heavily. this strikes me as the most striking method of improving the intake system.
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Originally Posted by Tony
I have the GTECH RR with PASS software. A bit $$$ but well worth it. It has a great feature where you can email the GTECH files to one another and with the software be compared to your own car or others...Ive run mine agaisnt Ferraris..Vipers etc etc on the software.
Im not slamming you at all, but remember, a stop watch is only as accurate as the reaction time on the finger running it and the eyes scanning the rapidly rising speedo across 60mph. A least the GTECH is hands free and records everythign for you.
Im not slamming you at all, but remember, a stop watch is only as accurate as the reaction time on the finger running it and the eyes scanning the rapidly rising speedo across 60mph. A least the GTECH is hands free and records everythign for you.
Originally Posted by rob rossitto
pappy, you've done some really incredible research - automotive OEM quality stuff IMHO...
I picked up the devek aluminum "sale" shroud, dual 1300cfm spals, might put some extra vents w/rubber flaps in "dead" spots for extra flow/cooling at speed... was hoping they'd push more air than the mech stuff through the compartment at idle and keep air moving through the front too...not a lot of room for much else as you know/thought about louvers in the fender wells as a last resort, but your diverter seems like a clever way to further isolate the intakes...also did jet hot on the headers to keep temps down, but was advised NOT to use header wrap/although I suspect it would help a bit too...
funny thing about gtech vs dyno - my race bike wrench sold his dyno (al holley) cause it never seemed to be accurate when bikes were run in the 'real world'... something about varying loads and wind, rates of accel, etc... suspect there's a place for both, but I'd probably trust gtech type stuff more for a real world measurement on most airflow type mods...
have you experimented w/the ott velocity stack and his airbox mods (larger bottom section)? I've got one coming, so if you want to "borrow"/experiment/ck it out/etc till I need it, I can leave it at greg's for you... claims of 8hp and better throttle response on a stock (+/-) GT were made by PO who now runs a FI system...might be interesting w/your other mods...
I picked up the devek aluminum "sale" shroud, dual 1300cfm spals, might put some extra vents w/rubber flaps in "dead" spots for extra flow/cooling at speed... was hoping they'd push more air than the mech stuff through the compartment at idle and keep air moving through the front too...not a lot of room for much else as you know/thought about louvers in the fender wells as a last resort, but your diverter seems like a clever way to further isolate the intakes...also did jet hot on the headers to keep temps down, but was advised NOT to use header wrap/although I suspect it would help a bit too...
funny thing about gtech vs dyno - my race bike wrench sold his dyno (al holley) cause it never seemed to be accurate when bikes were run in the 'real world'... something about varying loads and wind, rates of accel, etc... suspect there's a place for both, but I'd probably trust gtech type stuff more for a real world measurement on most airflow type mods...
have you experimented w/the ott velocity stack and his airbox mods (larger bottom section)? I've got one coming, so if you want to "borrow"/experiment/ck it out/etc till I need it, I can leave it at greg's for you... claims of 8hp and better throttle response on a stock (+/-) GT were made by PO who now runs a FI system...might be interesting w/your other mods...
Ceramic coatings work very well on exhaust systems. Wraps work until they leak minutely. As small openings allow air to contact the header a temperature differential occurs. If the delta becomes great enough we get cold spots on the tubing. Micro cracks begin to appear. These eventually result in leaks and even complete fractures. On cars which have disposable racing headers this is not important.
Louie provided the plans to create his stack. If you have one I would love to try it. I will be at Greg's on the 10th. Perhaps you could lend it to me. I would love to give it a go and provide a report.
Originally Posted by Andrew Olson
Just thinking here... all very interesting stuff by the way... I certainly see the benefits for ducting cool/cold air. No problems there. Where I'm having difficulty is understanding how this will generate ANY positive air pressure (a la super charging). Somewhat akin to Wally post regarding stalled air after the radiator, wouldn't the same be true for the air filter? The only way you'd be able to ram-air the 928 is to completely seal the intake tubes, filter box, etc. If there were any holes or leaks in the system, you'd lose all the pressure benefits.
Am I wrong?
Since I don't see any attempt to seal the system, I think your goal should be going after cool air alone. This may give you some design freedom. Good luck.
Am I wrong?
Since I don't see any attempt to seal the system, I think your goal should be going after cool air alone. This may give you some design freedom. Good luck.
Originally Posted by drnick
steve, i asked mark k about his airbox mod and you can see pics of it on his website. they have simply ducted air directly from the base of the windshield through the stock cavity there (with wiper motor etc) and into the airbox. i can remember a concern expressed about water ingestion but when i asked mark he admitted to having driven in the rain with no ill effect on at least one occasion when it was raining very heavily. this strikes me as the most striking method of improving the intake system.
I'm moving on to another phase of the experiment. Rob had an idea that I am following:
Originally Posted by rob rossitto
just a thought, but if it's heat build up that's the enemy, would bigger fans help? ie just blast more air under there to keep the whole compartment cooler, and there would be less build up in front, hence cooler air for the intake tubes...
#67
Rob had an idea that I am following:
airbox w/stack shipped yesterday, I'll let you know when it's here/get it to greg asap for you...
guess I'll settle w/jet hot, although maybe a compartment diverter/heat shield could seperate the exhaust heat from the top 1/2?... just what we need, another shield to mess with...
math 1st? tried that on my pistons and got into a real mess... I'll just follow anyone's lead that works - and it sounds like y'all are onto a thing or two for sure (sorry, superbowl drawl/hangover)...
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You could also put in a larger capacity rad that would hold a bit more water to give you a bigger reserve/absorbtive capacity for those hot days.. That coupled with the fans would be interesting to monitor..
I like the thermistor or aux fan switch in parallel to the temp switch...
Oh, cold water and warm oil makes a happy motor happier...
my .02,
I like the thermistor or aux fan switch in parallel to the temp switch...
Oh, cold water and warm oil makes a happy motor happier...
my .02,
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Originally Posted by rob rossitto
just don't tell anybody where you got it, or you'll be in the padded cell next to mine...
airbox w/stack shipped yesterday, I'll let you know when it's here/get it to greg asap for you...
guess I'll settle w/jet hot, although maybe a compartment diverter/heat shield could seperate the exhaust heat from the top 1/2?... just what we need, another shield to mess with...
math 1st? tried that on my pistons and got into a real mess... I'll just follow anyone's lead that works - and it sounds like y'all are onto a thing or two for sure (sorry, superbowl drawl/hangover)...
airbox w/stack shipped yesterday, I'll let you know when it's here/get it to greg asap for you...
guess I'll settle w/jet hot, although maybe a compartment diverter/heat shield could seperate the exhaust heat from the top 1/2?... just what we need, another shield to mess with...
math 1st? tried that on my pistons and got into a real mess... I'll just follow anyone's lead that works - and it sounds like y'all are onto a thing or two for sure (sorry, superbowl drawl/hangover)...
The diverter (as it is today) might not be required if the thermistor solution works. The cooling effect is great. With a thermistor in parallel with the aux fan switch a half diverter (like the one Louie designed) might be effective. That would eliminate the hoses to the nose. My water temp on the freeway is down near 1/3 on the gauge. It never, ever, ran that cool before.
Originally Posted by blau928
You could also put in a larger capacity rad that would hold a bit more water to give you a bigger reserve/absorbtive capacity for those hot days.. That coupled with the fans would be interesting to monitor..
I like the thermistor or aux fan switch in parallel to the temp switch...
Oh, cold water and warm oil makes a happy motor happier...
my .02,
I like the thermistor or aux fan switch in parallel to the temp switch...
Oh, cold water and warm oil makes a happy motor happier...
my .02,
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It would be interesting to research what the new Subaru uses, to keep water out of their hood scoop.
Assuming it is functional...
If so, a *really* low-profile version, over the airbox, might do the trick...
Assuming it is functional...
If so, a *really* low-profile version, over the airbox, might do the trick...
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Originally Posted by bcdavis
It would be interesting to research what the new Subaru uses, to keep water out of their hood scoop.
Assuming it is functional...
If so, a *really* low-profile version, over the airbox, might do the trick...
Assuming it is functional...
If so, a *really* low-profile version, over the airbox, might do the trick...
Louie and I have been discussing the induction system. Several people have tried similar experiments and the results were not good. If the stock MAF is retained the air must enter from the sides. The hood of the car is also a negative pressure zone which creates additional issues. The areas that have positive pressure are the base of the windshield and the nose. I am tempted to reinstall my nose snout, install a fully closed diverter, and measure the air box pressure again. I have not tried a closed diverter yet. All of the air would come off the top of the nose from between the headlights. Any water entering the nose snout would utilize the stock Porsche hood drains (4 traps in the side cross members).
Originally Posted by rob rossitto
not sure on "correct' temp limits, but w/my forged stuff if I ran too cold it might be an issue... any idea what 1/3 on the pcar gauge relates to in the C or F scales?
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BTW: Speed Channel has been doing an Acura RSX build up (track car). Guess what? The same principals are being applied. Low temp thermostats, fan switches, radiator, insulated intake tube, air box blanket, etc. And for nay sayers, this is a track car, not a street car, and they are posting significant dyno gains (also reduced lap times).
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Originally Posted by rob rossitto
... any idea what 1/3 on the pcar gauge relates to in the C or F scales?
I cant recall the numbers but i can find out exactly again next time i drive.. My guess is it will vary a bit from car to car. Ive found the stock gauge very slow to react compared to my Autometer gauge whose sensor is about 2 inches away from the stock pickup.
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Originally Posted by Tony
I cant recall the numbers but i can find out exactly again next time i drive.. My guess is it will vary a bit from car to car. Ive found the stock gauge very slow to react compared to my Autometer gauge whose sensor is about 2 inches away from the stock pickup.