[ds968]

   

 

 

He's still alive , he's still alive !   ( flash )        :clap: 

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[Roboman]

in summary though, the snorkel is there to both pick up cold air from the lower grill, to control noise, and to pass emissions tests and cold start tests.  in normal use, the snorkel is not needed, and in fact limits the air intake.  removing it improves performance, but in extremely cold environments, can make for harder starts, and the noise will increase.

Thanks Flash, controlling noise and emissions tests seem key here as simply "chopping the bend off the snorkel" would result in less restricted airflow from the same cool air (and I'm not in a geographical region where cold starts are an issue). It is unfortunate that the front bumper design effectively precludes designing a scoop leading from the front grill ..... however compressing that air would also tend to raise the temperature. Mmmmm, at 4000rpm the engine is drawing 100lt/sec. A scoop will increase the volume and density of air available to be drawn into the cylinders but at the same time raise its temperature and hence make the air less dense. At 100lt/sec all the effects on the air will be from the scoop, any attempt to cool that air during its transfer to the MAF will have minimal effect. I guess that's why an SC is just a smooth "coil" with no cooling fins .... no point in cooling fins as the air is transiting the tube too quickly (sorry if I'm stating the obvious, some of us have come to this musing late in life). Okay, at this point I'm aware that I have no testing equipment and that earlier someone said "don't overthink this" .... good advice! But I still have questions....


For those with "velocity stacks", I'm assuming you have the shroud in place to stop hot engine bay air entering the intake chamber. However did you also modify the "wall" through which the snorkel passes?

I guess as a minimum you cut away the rubber around the snorkel hole to make it larger, but anything else to increase the airflow.into the chamber where the air box is housed?


I can sense DS thinking it's much easier to mount an SC .... probably takes less time and with far better results


Waylander, I agree with you that the returns are minimal for the time invested, but it's also a very enjoyable distraction.

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[Chris Vais]

Once you have completed the airbox mod and removed the snorkel, you do need to have some kind of shroud so as not to take in warm air from the engine bay. These cars originally came with a plastic shroud that covered the area in question, but the shroud was discontinued. If you can't find one in a salvage yard you can order an airbox shroud from RS Barn that will serve the same purpose.

 

I don't think the mod increases induction noise to the point where you might be at risk of having an illegal car. I only notice the induction howl when the throttle is wide open.

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[Waylander]

Be interesting to fit a temp sensor inside the air box pre and post mod, with and without the shroud


As the mod is a waste of time if the air temp is 10 degrees higher after the mod with no shroud


And real world tests, not parked on the drive

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[94SilverCab]

Be interesting to fit a temp sensor inside the air box pre and post mod, with and without the shroud


As the mod is a waste of time if the air temp is 10 degrees higher after the mod with no shroud


And real world tests, not parked on the drive

 

Bob Larson (Flash) and Dave Greimann did extensive research and dyno testing. At the time the testing was done, the 968 community was so fractured that it would be impossible to have certain members of the community believe that grass is green if certain other members made that assertion. Go back and read the original threads...the results are air tight 

 

Jay 

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[ds968]

 

Bob Larson (Flash) and Dave Greimann did extensive research and dyno testing. At the time the testing was done, the 968 community was so fractured that it would be impossible to have certain members of the community believe that grass is green if certain other members made that assertion. Go back and read the original threads...the results are air tight 

 

Jay 

Completely agree .  

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[Roboman]

Be interesting to fit a temp sensor inside the air box pre and post mod, with and without the shroud

As the mod is a waste of time if the air temp is 10 degrees higher after the mod with no shroud

And real world tests, not parked on the drive

Now that is an interesting notion..... but I also continue with the next post ...

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[Roboman]

Bob Larson (Flash) and Dave Greimann did extensive research and dyno testing. At the time the testing was done, the 968 community was so fractured that it would be impossible to have certain members of the community believe that grass is green if certain other members made that assertion. Go back and read the original threads...the results are air tight 

 

Jay

With real respect to all you guys that got involved with the mods and testing, progress is not made by just acquiescing or following. Often as not it is the new kid on the block with "crazy ideas" who moves a project forwards as a step rather than an iteration. So as time permits I shall have a dig at this and will let you know ..... and if I make no progress I shall be happy to say so ... but experimentally I still think Waylander's temp sensor affords interesting info/control data.

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[94SilverCab]

Hey man, your car your money...have a good time and by all means, report your progress...  

 

Jay

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[Kaj Hallstrom]

I modified my box a couple of years ago. Did a miracle happen?.....no, but the sound changed a little and the power improved a little...I am guessing about 5hp...and that was it. It is easy to do though.

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[Roboman]

I modified my box a couple of years ago. Did a miracle happen?.....no, but the sound changed a little and the power improved a little...I am guessing about 5hp...and that was it. It is easy to do though.

Yes I'm not expecting much improvement else everyone would have done it already, I just like to try stuff for myself.... I can't understand the inside of the top, it is as though it's deliberately designed to cause turbulence instead of lamina flow .... odd!


Enough on this topic for me. When I get to it .....

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[Rolls912]

Great reading.

 

I have found the round trim pieces for the airbox holes on RSBarn. Is there another option out there that someone has found?

 

Also, thinking about the chips. Is there much difference between 1&2. Doesn’t appear to be a lot of info on the website.

 

thanks.

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[94SilverCab]

Great reading.

 

I have found the round trim pieces for the airbox holes on RSBarn. Is there another option out there that someone has found?

 

Also, thinking about the chips. Is there much difference between 1&2. Doesn’t appear to be a lot of info on the website.

 

thanks.

RS Barn is pretty much the only 968 specialty performance engineer, not a lot of choices with such low production numbers.

 

Chip #2 is for cars with header, not for use with just airbox mod and/or cat back systems.

 

Regards,

 

Jay

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[MCL968]

Great reading.

 

I have found the round trim pieces for the airbox holes on RSBarn. Is there another option out there that someone has found?

 

Also, thinking about the chips. Is there much difference between 1&2. Doesn’t appear to be a lot of info on the website.

 

thanks.

I removed the front of the box and replaced it with a piece of flat black plexiglass. Then I used velocity stacks from an airbox from a motorcycle. I was told that speaker ports will also work to smooth the airflow and reduce turbulence.

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[Rolls912]

Why don’t more people put the air-box on the shelf  (so it’s unblemished) and simply use a k&n cone? Surely the slightly hot air wouldn’t make that much difference?

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[94SilverCab]

Why don’t more people put the air-box on the shelf  (so it’s unblemished) and simply use a k&n cone? Surely the slightly hot air wouldn’t make that much difference?

 The issue is not just "cold air" but "still, cold air"...read, read, read...

 

Jay

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[rxter]

 

Bob Larson (Flash) and Dave Greimann did extensive research and dyno testing. At the time the testing was done, the 968 community was so fractured that it would be impossible to have certain members of the community believe that grass is green if certain other members made that assertion. Go back and read the original threads...the results are air tight 

 

Jay 

Hard to believe that an old car community could be fractured - but people are idiots I guess.  Good to see Bob pop up out of the ether.  And FWIW Bob's mods transformed this car from a fun flexible runabout to a legit sports car.  I used every piece of performance and handling kit that he made and our drives were so much the better for it.

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[ds968]

Hard to believe that an old car community could be fractured - but people are idiots I guess.  Good to see Bob pop up out of the ether.  And FWIW Bob's mods transformed this car from a fun flexible runabout to a legit sports car.  I used every piece of performance and handling kit that he made and our drives were so much the better for it.

 

:clap:

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[MCL968]

Hard to believe that an old car community could be fractured - but people are idiots I guess.  Good to see Bob pop up out of the ether.  And FWIW Bob's mods transformed this car from a fun flexible runabout to a legit sports car.  I used every piece of performance and handling kit that he made and our drives were so much the better for it.

Agreed, the upper and lower front braces made a big difference, but the chassis brace (roll bar?) made the car track so straight through corners that it seemed like a different car. The airbox mod, chip, Koni's and cat back system transformed the car even further.

 

It was not a single thing, but the combination and interaction of the elements that made the difference. Without Flash's parts and the RS barn upgrades, this old car would not be nearly as much fun to drive. I wish Flash would have gotten around to finishing his chip for the NA cars. I bet it would have also made a real difference.

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[rxter]

There were a couple of other chips made in the earlier days.  I had a Weltmeister in mine and it worked very well.  I still have it in the garage somewhere...

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