Power increase from removing stock air box?
04-09-2012, 11:46 AM
#17
Three Wheelin'
04-09-2012, 11:51 AM
#18
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I get 365rwhp on a dynapack (a very low reading one) with the same setup as a 968 turbo S(the orange car in the pics). Would be close to 400rwhp at 16.5 psi on a Dynojet. Can't be too restrictive.
04-09-2012, 12:09 PM
#19
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i bet if he removed it, he would gain a few horsepower.
go try this. get a glass of water, now get a standard size straw and drink the water. now get 2 straws, then drink. and that became a lot easier didn't it.
same situation with the airbox.
go try this. get a glass of water, now get a standard size straw and drink the water. now get 2 straws, then drink. and that became a lot easier didn't it.
same situation with the airbox.
04-09-2012, 03:55 PM
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04-10-2012, 05:20 AM
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While I agree with this concept, now try drinking a glass of warm murky water with 2 straws then go back to drinking a nice glass of cold purified water through one straw. It must be a cold air intake set up in order to achieve optimum performance. Otherwise, the removal of the airbox on its own without proper routing to a cool source of air may end up costing you HP.
04-10-2012, 08:15 AM
#23
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While I agree with this concept, now try drinking a glass of warm murky water with 2 straws then go back to drinking a nice glass of cold purified water through one straw. It must be a cold air intake set up in order to achieve optimum performance. Otherwise, the removal of the airbox on its own without proper routing to a cool source of air may end up costing you HP.
if you're going to take the airbox off and put a simple cone filter with an adapter to the AFM you're going to loose power. to modify the snorkel like someone has posted, is a good idea but the biggest restriction is the actual AFM. if someone makes a MAF that goes in that spot (i'm sure it's not that difficult) and puts the larger snorkel on the airbox, you'll have a huge gain in power
04-10-2012, 08:25 AM
#24
If you keep the rectangular section of the airbox where it meets AFM it will still be restrictive with a MAF.
The most restrictive part is the snorkel about halfways.
I ran the airbox on my 3.0 and it was a HUGE restriction, less so without the snorkel but enough to make a difference in spool and upper RPM breathing with a cone filter.
I also like the stock look better but it just doesn't work, at least on my engine.
The most restrictive part is the snorkel about halfways.
I ran the airbox on my 3.0 and it was a HUGE restriction, less so without the snorkel but enough to make a difference in spool and upper RPM breathing with a cone filter.
I also like the stock look better but it just doesn't work, at least on my engine.
Last edited by Thom; 04-10-2012 at 08:48 AM.
04-10-2012, 12:45 PM
#25
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Now that makes sense, in a way.
if you're going to take the airbox off and put a simple cone filter with an adapter to the AFM you're going to loose power. to modify the snorkel like someone has posted, is a good idea but the biggest restriction is the actual AFM. if someone makes a MAF that goes in that spot (i'm sure it's not that difficult) and puts the larger snorkel on the airbox, you'll have a huge gain in power
if you're going to take the airbox off and put a simple cone filter with an adapter to the AFM you're going to loose power. to modify the snorkel like someone has posted, is a good idea but the biggest restriction is the actual AFM. if someone makes a MAF that goes in that spot (i'm sure it's not that difficult) and puts the larger snorkel on the airbox, you'll have a huge gain in power
04-10-2012, 01:57 PM
#26
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Now that makes sense, in a way.
if you're going to take the airbox off and put a simple cone filter with an adapter to the AFM you're going to loose power. to modify the snorkel like someone has posted, is a good idea but the biggest restriction is the actual AFM. if someone makes a MAF that goes in that spot (i'm sure it's not that difficult) and puts the larger snorkel on the airbox, you'll have a huge gain in power
if you're going to take the airbox off and put a simple cone filter with an adapter to the AFM you're going to loose power. to modify the snorkel like someone has posted, is a good idea but the biggest restriction is the actual AFM. if someone makes a MAF that goes in that spot (i'm sure it's not that difficult) and puts the larger snorkel on the airbox, you'll have a huge gain in power
Last edited by RajDatta; 04-10-2012 at 04:15 PM.
04-10-2012, 02:20 PM
#27
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This is from Nize on another P-car forum from 2008. Believe this is a dyno tested difference between MAF/MAP and snorkel and stock air box where that was the only change between runs.
"i've compared performance with the stock air box and snorkle versus just a filter attached to the compressor inlet.
the difference is significant, and it's definitely worth removing the stock air box and snorkle if you want maximum turbo performance.
all things being equal, the spoolup is about 200rpm faster without the stock afm/snorkle, but the real difference is after 4500rpm when the air restriction becomes really noticeable. the result is way more area under the curve and a gain of over 36whp.
it's obvious that most of the power and performance gains from a MAF setup is actually coming from removing the stock intake restrictions. if your mods can support it (MAP or MAF), i would highly recommend removing the stock AFM and snorkle for best performance gains."
"i've compared performance with the stock air box and snorkle versus just a filter attached to the compressor inlet.
the difference is significant, and it's definitely worth removing the stock air box and snorkle if you want maximum turbo performance.
all things being equal, the spoolup is about 200rpm faster without the stock afm/snorkle, but the real difference is after 4500rpm when the air restriction becomes really noticeable. the result is way more area under the curve and a gain of over 36whp.
it's obvious that most of the power and performance gains from a MAF setup is actually coming from removing the stock intake restrictions. if your mods can support it (MAP or MAF), i would highly recommend removing the stock AFM and snorkle for best performance gains."
Even if the power gains would be half of that I think it's worth doing something to improve the flow.
Snorkel from airbox to chasis is the most resistive part of airbox. Thats why 968 turbo S had this version:
You can buy this ETG advanced snorkel, but at 350€ its not cheap.
http://cgi.ebay.de/ws/eBayISAPI.dll?...691358171.html
You can buy this ETG advanced snorkel, but at 350€ its not cheap.
http://cgi.ebay.de/ws/eBayISAPI.dll?...691358171.html
I'm changing to a hood with a Turbo RS style vent to make the IC more efficient and I think that removing the airbox gives even better IC air flow.
Is the airbox from a 951, and is the rectangular hole to the AFM still the original size?
If you keep the rectangular section of the airbox where it meets AFM it will still be restrictive with a MAF.
The most restrictive part is the snorkel about halfways.
I ran the airbox on my 3.0 and it was a HUGE restriction, less so without the snorkel but enough to make a difference in spool and upper RPM breathing with a cone filter.
I also like the stock look better but it just doesn't work, at least on my engine.
The most restrictive part is the snorkel about halfways.
I ran the airbox on my 3.0 and it was a HUGE restriction, less so without the snorkel but enough to make a difference in spool and upper RPM breathing with a cone filter.
I also like the stock look better but it just doesn't work, at least on my engine.
/Dea
04-10-2012, 02:21 PM
#28
Two big restriction for the airbox, one is stated above is the opening at the bottom, the other is the opening at the top where the snorkel attaches. I tried to keep the airbox but eventually the gains out way the esthetics IMPO Kevincnc managed to upgrade the AFM with a MAF very nice work but a pain I'm sure as not many others have done it. He also looked into widening the snorkel to 3" but I'm guessing it never happened because that's not where the big restriction is. At then end of the day it looks like you either make an airbox from scratch or ditch it for a cone and enjoy quicker spool and extra HP.. my02
https://rennlist.com/forums/944-turb...-pictures.html - SUPER STEALTH MAF
https://rennlist.com/forums/944-turb...intersted.html - 3" SNORKEL
https://rennlist.com/forums/944-turb...-pictures.html - SUPER STEALTH MAF
https://rennlist.com/forums/944-turb...intersted.html - 3" SNORKEL
04-10-2012, 03:01 PM
#29
Although I used to be convinced that I could make the airbox work on my engine, I would now argue that where it is placed it would probably allow for not much cooler air than a cone filter in the usual place would.
With the cone filter near the fender air has less way to travel before reaching the turbo, and there is only one bend on this path. Not quite so with the airbox.
With the cone filter near the fender air has less way to travel before reaching the turbo, and there is only one bend on this path. Not quite so with the airbox.
04-10-2012, 03:17 PM
#30
Rennlist Member
Thanks!, just what I was looking for.
Even if the power gains would be half of that I think it's worth doing something to improve the flow.
Looks great but the price is way off....
I'm changing to a hood with a Turbo RS style vent to make the IC more efficient and I think that removing the airbox gives even better IC air flow.
Do you have a Naca duct intake on the hood?
Is the airbox from a 951, and is the rectangular hole to the AFM still the original size?
I think the best solution would be to put a cone filter inside the fender. It's strange that no one sells a kit to do that...
/Dea
Even if the power gains would be half of that I think it's worth doing something to improve the flow.
Looks great but the price is way off....
I'm changing to a hood with a Turbo RS style vent to make the IC more efficient and I think that removing the airbox gives even better IC air flow.
Do you have a Naca duct intake on the hood?
Is the airbox from a 951, and is the rectangular hole to the AFM still the original size?
I think the best solution would be to put a cone filter inside the fender. It's strange that no one sells a kit to do that...
/Dea
Airbox is same as 951 airbox. I use a MAF from Scivision, which was designed to work with an airbox. It uses adapters to make a rectangular hole work with a round MAF.
Regards.
Raj