Turbo Sizing Tips and Compressor Map How-To's - Page 2 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

uiuc240 · 11-27-2002, 11:03 AM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Kreator @ Nov. 26 2002,10:14)</td></tr><tr><td id="QUOTE">Ok i'll be reading that a bit later on (comp sci project gettin the fuckin best of me). On the other hand, a bit off topic: I'm trying to decide on an oil pressure gauge. The stock says im to get 60-70 at 3000rpm on n/a ka. Can i figure out the highest it'll go? tryin to decide should i go with 0-100 or 0-150psi?

edit: *<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'> *post 999 *<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

edit2: the aftermarket bovs have the screw to adjust the pressure they open up at right? I was looking at 1g dsm bov, but couldnt' find one.... how do i go about it, and any clue what it's set at initially? (saving up my 1000th post for somethin rlly good <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt='

'>)</td></tr></table><span id='postcolor'>
The 0-100 will be fine.  IIRC, there is a bypass on the oil pump that never allows it to go above ~80 psi.  So 100 psi will be perfecto.

Yes, almost all aftermarket BOVs have adjustment screws...I think there is some lame Greddy one that doesn't...don't buy one that doesn't.

On a 1g DSM BOV, you have to put the dang thing in a vise and crush it to get it to hold a certain psi.  IMO, it makes a lot more sense to just spend a Benjamin and buy a used *real* BOV before you get some jenky DSM one.  But that's me.  And I have that Blitz.  So I'm biased.

Jeff, I think we should change the title of this before we archive it.  Perhaps something like "BOVs and other turbo queries" or something.  Since we basically talked about EVERYTHING.

Eric

uiuc240 · 11-27-2002, 03:11 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Kreator @ Nov. 26 2002,4:08)</td></tr><tr><td id="QUOTE">OK, but if at 7000rpm my engine requires 200CFM n/a, how much would it require at 8 psi? is it CFM*(pressure ratio) or something?</td></tr></table><span id='postcolor'>
I'm not sure what your question is asking, but I have re-ran the numbers and gotten MUCH better info.  Here goes:

V = 292 CFM @ 6900
n = (24.7*292*29)/(10.73*535) = 36.43 lbs/min
Va = 292*.85 = 248 CFM
intercooled n = (24.7*248*29)/(10.73*535) = 28.08 lbs/min
T-out = 535 + (535*(-1+1.68^0.263))/.72 = 643 R = 183 F
corrected flow for Turbonetics maps:
(28.08*(535/545)^0.5)/(14.7/13.949) = 26.4 lbs/min
P = 1.68 (10 psi guage)

So, with a P of 1.68 and flow of 26.4 lbs/min, I went to the chart for the T04B H-3 compressor.

Wow.

You'll be in the 74% range with that turbo at full throttle at redline with 10 psi.  Simply awesome.

Unless I'm totally missing something.

If you lower the PSI, that lowers the airflow and the outlet temp.

I reran the numbers for 8 psi.

n [corrected] = 25.57 lbs/min
P = 1.54

That still leaves you in the 74% range!!!

Wow.  I think there were some SERIOUS problems with the last formula.  This one is much better.

Eric

Kreator · 11-28-2002, 10:40 AM

Ok yeah, this seems more accurate.
I recalculated all this stuff, and with a T3 "50" which i'm getting and 4psi boost, my turbo will be in >65% efficiency range till about 4000rpm. And the air coming in would approximately be 140*. Not bad for a daily driver, what do you think?

edit: again about bovs. uiuc, there is a screw on top of blitz super sound. Is that to adjust the pressure at which it releases? Or are they spring adjustable, meanin u gotta swap in a different spring to modify the settings? Finally, can anyone tell me if the HKS super blow off valve is adjustable or not? Cuz i'm not sure and need to know. thanx.

uiuc240 · 11-29-2002, 03:56 PM

140* and 65% should be quite nice.  rock on.

the screw adjusts the pressure at which the piston stays closed (on the Blitz).  that also has an effect on how easily it opens, too.  if i have mine adjusted so it doesn't leak at idle, it doesn't really blow off unless i have more then 3-4 psi of pressure built up when i close the throttle.

i'm almost POSITIVE the HKS is adjustable.

Eric

Kreator · 11-29-2002, 05:45 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (uiuc240 @ Nov. 29 2002,3:56)</td></tr><tr><td id="QUOTE">i'm almost POSITIVE the HKS is adjustable.</td></tr></table><span id='postcolor'>
Well there is no screw on the hks one. Plus i just talked to an mr2 guy who had it before, and he said it was not adjustable. But then the question arises to what setting it's then set from the factory <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

uiuc240 · 11-30-2002, 02:16 PM

are you talking about the old HKS one or the new HKS one?

now that I think about it, I think because of the way the HKS is designed (it's different from the regular piston-type ones), that maybe it doesn't NEED to be adjusted.  maybe it just flat-out works.

Eric

Kreator · 11-30-2002, 04:44 PM

I was talking about this one: http://cgi.ebay.com/ebaymot....2460815

But not to worry. I bitched at myself for being a greedy bish and just payed $143 for the blitz super sound shipped to my house  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

uiuc240 · 11-30-2002, 05:06 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Kreator @ Nov. 30 2002,4:44)</td></tr><tr><td id="QUOTE">I bitched at myself for being a greedy bish and just payed $143 for the blitz super sound shipped to my house *<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'></td></tr></table><span id='postcolor'>
Hehehe...Same as me!  Awesome

Eric

*Jeff240sx* · 12-02-2002, 10:44 PM

To the archives...
-Jeff

11-27-2002, 11:03 AM	#31
uiuc240 Nissanaholic! Join Date: Apr 2002 Location: Naperville, IL Age: 30 Posts: 2,093 Trader Rating: (0)	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Kreator @ Nov. 26 2002,10:14)</td></tr><tr><td id="QUOTE">Ok i'll be reading that a bit later on (comp sci project gettin the fuckin best of me). On the other hand, a bit off topic: I'm trying to decide on an oil pressure gauge. The stock says im to get 60-70 at 3000rpm on n/a ka. Can i figure out the highest it'll go? tryin to decide should i go with 0-100 or 0-150psi? edit: <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'> post 999 <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'> edit2: the aftermarket bovs have the screw to adjust the pressure they open up at right? I was looking at 1g dsm bov, but couldnt' find one.... how do i go about it, and any clue what it's set at initially? (saving up my 1000th post for somethin rlly good <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=''>)</td></tr></table><span id='postcolor'> The 0-100 will be fine.  IIRC, there is a bypass on the oil pump that never allows it to go above ~80 psi.  So 100 psi will be perfecto. Yes, almost all aftermarket BOVs have adjustment screws...I think there is some lame Greddy one that doesn't...don't buy one that doesn't. On a 1g DSM BOV, you have to put the dang thing in a vise and crush it to get it to hold a certain psi.  IMO, it makes a lot* more sense to just spend a Benjamin and buy a used real BOV before you get some jenky DSM one.  But that's me.  And I have that Blitz.  So I'm biased. Jeff, I think we should change the title of this before we archive it.  Perhaps something like "BOVs and other turbo queries" or something.  Since we basically talked about EVERYTHING. Eric __________________ 2002 Mazda Protege5 1989 S13 w/SR20DET (sold)

11-27-2002, 03:11 PM	#32
uiuc240 Nissanaholic! Join Date: Apr 2002 Location: Naperville, IL Age: 30 Posts: 2,093 Trader Rating: (0)	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Kreator @ Nov. 26 2002,4:08)</td></tr><tr><td id="QUOTE">OK, but if at 7000rpm my engine requires 200CFM n/a, how much would it require at 8 psi? is it CFM(pressure ratio) or something?</td></tr></table><span id='postcolor'> I'm not sure what your question is asking, but I have re-ran the numbers and gotten MUCH better info.  Here goes: V = 292 CFM @ 6900 n = (24.729229)/(10.73535) = 36.43 lbs/min Va = 292.85 = 248 CFM intercooled n = (24.724829)/(10.73535) = 28.08 lbs/min T-out = 535 + (535(-1+1.68^0.263))/.72 = 643 R = 183 F corrected flow for Turbonetics maps: (28.08(535/545)^0.5)/(14.7/13.949) = 26.4 lbs/min P = 1.68 (10 psi guage) So, with a P of 1.68 and flow of 26.4 lbs/min, I went to the chart for the T04B H-3 compressor. Wow. You'll be in the 74% range with that turbo at full throttle at redline with 10 psi.  Simply awesome. Unless I'm totally missing something. If you lower the PSI, that lowers the airflow and the outlet temp. I reran the numbers for 8 psi. n [corrected] = 25.57 lbs/min P = 1.54 That still leaves you in the 74% range!!! Wow.  I think there were some SERIOUS problems with the last formula.  This one is much better. Eric __________________ 2002 Mazda Protege5 1989 S13 w/SR20DET (sold)

11-28-2002, 10:40 AM	#33
Kreator Nissanaholic! Join Date: Mar 2002 Location: MD Age: 26 Posts: 1,974 Trader Rating: (0)	Ok yeah, this seems more accurate. I recalculated all this stuff, and with a T3 "50" which i'm getting and 4psi boost, my turbo will be in >65% efficiency range till about 4000rpm. And the air coming in would approximately be 140*. Not bad for a daily driver, what do you think? edit: again about bovs. uiuc, there is a screw on top of blitz super sound. Is that to adjust the pressure at which it releases? Or are they spring adjustable, meanin u gotta swap in a different spring to modify the settings? Finally, can anyone tell me if the HKS super blow off valve is adjustable or not? Cuz i'm not sure and need to know. thanx. __________________ http://fc-zenit.ru/images/logo_zenit.gif кто болеет за Зенит, у того всегда стоит!

11-29-2002, 03:56 PM	#34
uiuc240 Nissanaholic! Join Date: Apr 2002 Location: Naperville, IL Age: 30 Posts: 2,093 Trader Rating: (0)	140* and 65% should be quite nice.  rock on. the screw adjusts the pressure at which the piston stays closed (on the Blitz).  that also has an effect on how easily it opens, too.  if i have mine adjusted so it doesn't leak at idle, it doesn't really blow off unless i have more then 3-4 psi of pressure built up when i close the throttle. i'm almost POSITIVE the HKS is adjustable. Eric __________________ 2002 Mazda Protege5 1989 S13 w/SR20DET (sold)

11-29-2002, 05:45 PM	#35
Kreator Nissanaholic! Join Date: Mar 2002 Location: MD Age: 26 Posts: 1,974 Trader Rating: (0)	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (uiuc240 @ Nov. 29 2002,3:56)</td></tr><tr><td id="QUOTE">i'm almost POSITIVE the HKS is adjustable.</td></tr></table><span id='postcolor'> Well there is no screw on the hks one. Plus i just talked to an mr2 guy who had it before, and he said it was not adjustable. But then the question arises to what setting it's then set from the factory <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> __________________ http://fc-zenit.ru/images/logo_zenit.gif кто болеет за Зенит, у того всегда стоит!

11-30-2002, 02:16 PM	#36
uiuc240 Nissanaholic! Join Date: Apr 2002 Location: Naperville, IL Age: 30 Posts: 2,093 Trader Rating: (0)	are you talking about the old HKS one or the new HKS one? now that I think about it, I think because of the way the HKS is designed (it's different from the regular piston-type ones), that maybe it doesn't NEED to be adjusted.  maybe it just flat-out works. Eric __________________ 2002 Mazda Protege5 1989 S13 w/SR20DET (sold)

11-30-2002, 04:44 PM	#37
Kreator Nissanaholic! Join Date: Mar 2002 Location: MD Age: 26 Posts: 1,974 Trader Rating: (0)	I was talking about this one: http://cgi.ebay.com/ebaymot....2460815 But not to worry. I bitched at myself for being a greedy bish and just payed $143 for the blitz super sound shipped to my house  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'> __________________ http://fc-zenit.ru/images/logo_zenit.gif кто болеет за Зенит, у того всегда стоит!

11-30-2002, 05:06 PM	#38
uiuc240 Nissanaholic! Join Date: Apr 2002 Location: Naperville, IL Age: 30 Posts: 2,093 Trader Rating: (0)	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Kreator @ Nov. 30 2002,4:44)</td></tr><tr><td id="QUOTE">I bitched at myself for being a greedy bish and just payed $143 for the blitz super sound shipped to my house *<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'></td></tr></table><span id='postcolor'> Hehehe...Same as me!  Awesome Eric __________________ 2002 Mazda Protege5 1989 S13 w/SR20DET (sold)

12-02-2002, 10:44 PM	#39
Jeff240sx I hate you too... Join Date: Jul 2001 Location: Tampa, FL Age: 26 Posts: 5,843 Trader Rating: (0) Rides Gallery: Jeff240sx	To the archives... -Jeff __________________ Driving a Hyundai now.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode