VTDA Temp analysis including feed and Gasket effects...(Lotsa charts!)..>
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Joined: Dec 2000
Posts: 53,281
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VTDA Temp analysis including feed and Gasket effects...(Lotsa charts!)..>
From yesterday, I finally have all the data for your review.. The method for these various runs were as follows:
1) One Datalogger placed in the VTDA mouth, and the second in the engine compartment zip tied to the strut bar just above the N75.
2) Started with a cold engine, left the neighborhood (minutes 0-5) and did a 30 minute route. Initial country highway, than high speed back roads (15-25), a little traffic (minutes 25-30) and home. Let the car idle for 5 minutes at the end.(30-36)
3) Run 1 (Cool) Engine compartment: Low profile gasket in place for some venting. VTDA: Feeds in place and operational.
4) Run 2 (Hot) Stock Firewall to hood gasket, Feeds blocked
5) Run 3: (Trim) Low profile gasket, Feeds blocked
Run 1: Good temp differentials between VTDA and Vented engine compartment
<img src="http://images20.fotki.com/v356/photos/7/7305/4257627/Tempsvented-vi.jpg">
Run 2: Unvented engine, feeds blocked. Notice the higher engine compartment temps. VTDA still seems to be effective at blocking reflective heat.
<img src="http://images14.fotki.com/v223/photos/7/7305/4257627/unvented-vi.jpg">
Comparison of the engine compartment temps, Vented and unvented. Combination of the feeds and Low trim lowers temps about 18 degrees when all is stabilized.
<img src="http://images20.fotki.com/v355/photos/7/7305/4257627/Enginecomparo-vi.jpg">
Run 3: Low trim, blocked feeds. Ambient at the start was a little higher (afternoon, and the car only had a 3 hour cool down), but it seems that all stabilized once rolling so comparisons should still be valid.
<img src="http://images19.fotki.com/v359/photos/7/7305/4257627/Tempslowtrimnofeeds-vi.jpg">
Some conclusions on Venting..From the next chart, the Trim seems to lower temps in the compartment pretty substantially (use stabilized readings from the 15 minute mark on). The Gasket change seems to make the biggest single difference on these temps. The Engine compartment is being ventilated at the base of the windshield. Using a low profile trim piece allows cooling air in at this low pressure area.
<img src="http://images19.fotki.com/v37/photos/7/7305/4257627/tempsengineallcombos-vi.jpg">
Adding feeds does more to reduce the actual temps at the VTDA mouth but has little effect on overal engine compartment temps as most of that air is probably being ingested by the intake.
<img src="http://images19.fotki.com/v27/photos/7/7305/4257627/tempsvtdaallcombos-vi.jpg">
Conclusions:
1) The VTDA does a pretty good job of scrubbing off heat
2) The low profile trim piece has a substantial effect on lowering engine compartment temps and probably improving the longevity of hoses and wiring
3) Feeds reduce actual inlet temps nicely but have a minimal impact on compartment heat.
Discuss!
Low profile vs OEM trim difference:
<img src="http://images20.fotki.com/v357/photos/7/7305/4257627/IMG_0964-vi.jpg"><ul><li><a href="http://public.fotki.com/ttschwing/new!_vtda_productio/vtda-temperature-tests/">A few more pics/charts here..</a></li></ul>
1) One Datalogger placed in the VTDA mouth, and the second in the engine compartment zip tied to the strut bar just above the N75.
2) Started with a cold engine, left the neighborhood (minutes 0-5) and did a 30 minute route. Initial country highway, than high speed back roads (15-25), a little traffic (minutes 25-30) and home. Let the car idle for 5 minutes at the end.(30-36)
3) Run 1 (Cool) Engine compartment: Low profile gasket in place for some venting. VTDA: Feeds in place and operational.
4) Run 2 (Hot) Stock Firewall to hood gasket, Feeds blocked
5) Run 3: (Trim) Low profile gasket, Feeds blocked
Run 1: Good temp differentials between VTDA and Vented engine compartment
<img src="http://images20.fotki.com/v356/photos/7/7305/4257627/Tempsvented-vi.jpg">
Run 2: Unvented engine, feeds blocked. Notice the higher engine compartment temps. VTDA still seems to be effective at blocking reflective heat.
<img src="http://images14.fotki.com/v223/photos/7/7305/4257627/unvented-vi.jpg">
Comparison of the engine compartment temps, Vented and unvented. Combination of the feeds and Low trim lowers temps about 18 degrees when all is stabilized.
<img src="http://images20.fotki.com/v355/photos/7/7305/4257627/Enginecomparo-vi.jpg">
Run 3: Low trim, blocked feeds. Ambient at the start was a little higher (afternoon, and the car only had a 3 hour cool down), but it seems that all stabilized once rolling so comparisons should still be valid.
<img src="http://images19.fotki.com/v359/photos/7/7305/4257627/Tempslowtrimnofeeds-vi.jpg">
Some conclusions on Venting..From the next chart, the Trim seems to lower temps in the compartment pretty substantially (use stabilized readings from the 15 minute mark on). The Gasket change seems to make the biggest single difference on these temps. The Engine compartment is being ventilated at the base of the windshield. Using a low profile trim piece allows cooling air in at this low pressure area.
<img src="http://images19.fotki.com/v37/photos/7/7305/4257627/tempsengineallcombos-vi.jpg">
Adding feeds does more to reduce the actual temps at the VTDA mouth but has little effect on overal engine compartment temps as most of that air is probably being ingested by the intake.
<img src="http://images19.fotki.com/v27/photos/7/7305/4257627/tempsvtdaallcombos-vi.jpg">
Conclusions:
1) The VTDA does a pretty good job of scrubbing off heat
2) The low profile trim piece has a substantial effect on lowering engine compartment temps and probably improving the longevity of hoses and wiring
3) Feeds reduce actual inlet temps nicely but have a minimal impact on compartment heat.
Discuss!
Low profile vs OEM trim difference:
<img src="http://images20.fotki.com/v357/photos/7/7305/4257627/IMG_0964-vi.jpg"><ul><li><a href="http://public.fotki.com/ttschwing/new!_vtda_productio/vtda-temperature-tests/">A few more pics/charts here..</a></li></ul>
Last edited by TTschwing; Oct 17, 2010 at 09:28 AM.
AudiWorld Super User
Joined: Feb 2005
Posts: 4,105
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Steve, you have me at a disadvantage gaskets. Could you clarify?
My experience with my VTDA has been a noticable improvement low-mid RPM range (2200 to 3800 rpm) torque/usable power.
It looks like the vents are effective at transmitting ambient air to the venturi or opening of the VTDA. It seems to me that the real benefit would be during the duty cycle of the turbo, which is where most people would want it.
Nice work.
It looks like the vents are effective at transmitting ambient air to the venturi or opening of the VTDA. It seems to me that the real benefit would be during the duty cycle of the turbo, which is where most people would want it.
Nice work.
Thread Starter
AudiWorld Uber User
Joined: Dec 2000
Posts: 53,281
Likes: 2
The Low profile trim..>>
Allows venting into the engine compartment at the low pressure area at the base of the Windshield. The OEM piece seals the hood and firewall completely, the low profile allows the air in...:-) ($15 shipped priority mail)
<img src="http://images20.fotki.com/v357/photos/7/7305/4257627/IMG_0964-vi.jpg">
<img src="http://images20.fotki.com/v357/photos/7/7305/4257627/IMG_0964-vi.jpg">
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