smaller box, need tuning help

[Xprime4 10+ year member]

so i made my box for my 18 q yesturday and i put it in the car. So far everything work wonder. Then i tried closing the trunk lid (accent hatchback) and oups.... //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

so i go to cut the box a little in height so the lid can be closed. right now the external dimension are 21,25heigh, 37,25 width and 22 deep for 8.2 before displacement and with a 6feetx4 inch aero port cut in 4 equal part of 17inchx4 so around 31hz of tuning. something like 7.6 after displacements...

Now if i have to shortened the heigh by 2,5 inch i would get like 7.2 before all displacement. But how will it affect the tuning if i leave the same aeros in the box? will it be higher or lower? how to get it back to around 30-32hz?

thank you , right now i feel so dumb:crazy:

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[scoob8000 10+ year member]

I do believe it will make the tuning higher

 

[Xprime4 10+ year member]

how long i need to shortened it for a 30hz tuning? 7.2 before displacement, 4inch x4 aeros

 

[scoob8000 10+ year member]

According to this site, ports need to be about 18" long.

http://www.carstereo.com/help/Articles.cfm?id=31

 

[FootlongSam 10+ year member]

anywhere from 16.25" (32htz) to 18.9" (30htz)

 

[Xprime4 10+ year member]

finaly i can only get like 6.5 before displacement... how long i need my 4 aeros to be ?

 

[Xprime4 10+ year member]

the car stereo website says something around 17inch , seems accurate? i wouldn't have to touch anything and I'll still be able to be at 32hz?

recommandation on how to short the box? circle saw?

 

[scoob8000 10+ year member]

When I did my port I checked a few sites (calculators) they all came up the same. The PSP site comes up with a different number for flared ports tho.

http://www.psp-inc.com/psp-inc.com/public_html/..%5Ccgi-bin%5Cport_length_calculator.cgi

Post a pic of the box. If it's just like a square and your gonna make it shorter, take the top off and use a circular saw with a rip fence to keep the cut level and put the top back on..

 

[Xprime4 10+ year member]

When I did my port I checked a few sites (calculators) they all came up the same. The PSP site comes up with a different number for flared ports tho.
http://www.psp-inc.com/psp-inc.com/public_html/..%5Ccgi-bin%5Cport_length_calculator.cgi

Post a pic of the box. If it's just like a square and your gonna make it shorter, take the top off and use a circular saw with a rip fence to keep the cut level and put the top back on..

i just finished removing the top sheet... it needed a lot of time but i manage to do it with some creativity.

I got to remove 3.5 inch, i made the cut lines around the box. I'll be calling a friend for the rest of it.....

It was sounding so nice on 8ft/cu. I hope it won't change too much without all the recommanded airspace //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif