HKS true dual power loss?!?!?
07-20-2008, 07:47 AM
#41
Originally Posted by gambino
So I bought an HKS true dual for my 07 based on hundreds of good reviews. Installed it, LOVE the sound, LOVE the looks (rolled me rear bumper too!). Only problem is my recent dyno......let me set this up for you.
I have had the car dynoed on 4 seperate occasions now (for different reasons) ALL ON THE SAME DYNO. The first three times were done stock and were consistent, the fourth time was three days ago with the exhaust and I was VERY disappointed with the results.
Dyno 1 - May 2007 - temp probably in the 60's - 266rwhp (stock)
Dyno 2 - November 2007 - temp in 40's - 266rwhp (stock)
Dyno 3 - April 2008 - temp high 50-s - 265rwhp (stock w/volks)
Dyno 4 - July 2008 - temp 100 - 233rwhp (volks/HKS)
Needless to say I was STUNNED. All these were done on the same dyno. My main question is could the very high temperature and bad air here in the summer be enough to make a 30+whp difference? Or is the HKS causing a power loss as well? Any input would be appreciated.
I have had the car dynoed on 4 seperate occasions now (for different reasons) ALL ON THE SAME DYNO. The first three times were done stock and were consistent, the fourth time was three days ago with the exhaust and I was VERY disappointed with the results.
Dyno 1 - May 2007 - temp probably in the 60's - 266rwhp (stock)
Dyno 2 - November 2007 - temp in 40's - 266rwhp (stock)
Dyno 3 - April 2008 - temp high 50-s - 265rwhp (stock w/volks)
Dyno 4 - July 2008 - temp 100 - 233rwhp (volks/HKS)
Needless to say I was STUNNED. All these were done on the same dyno. My main question is could the very high temperature and bad air here in the summer be enough to make a 30+whp difference? Or is the HKS causing a power loss as well? Any input would be appreciated.
07-20-2008, 08:12 AM
#43
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i think a nice intake would help your number with the bigger flowing exhaust your intake is not pulling in enough volume to stop air starving when both intake and exhaust valves are open.....(venturey (sp?)effect for you smarter ppl)
(same air in + more air out = loss of power)
get a nice intake to help with that and i bet your numbers will go up a bit and then like said many times above wait for a cooler day and the numbers will go even higher.
(same air in + more air out = loss of power)
get a nice intake to help with that and i bet your numbers will go up a bit and then like said many times above wait for a cooler day and the numbers will go even higher.
07-20-2008, 09:22 AM
#46
Originally Posted by gambino
yeah they have lifts
Same car, same day, same dyno, same tank of gas, same atmospheric conditions?
The only variable would be a change of exhaust.
I'll pay for the dyno.
07-20-2008, 09:47 AM
#47
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that is weird man. Import Tuner magazine dyno out that exhaust on a stock Z and the car gain about 15 hp and about the same for the torque. Have your car tune, and you might have the same result?
07-21-2008, 01:06 PM
#52
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Well we discovered the problem! The company uses an all wheel dyno with 2wd and 4wd settings. They forget to set the dyno to 2wd this last time so the numbers were off. I am going to try to get the car back in this week for a dyno for more accurate numbers 
...
07-21-2008, 01:27 PM
#54
Good to see you got to the root of the problem.
AND 411Z you really need to hit the books. Being 21 and not knowing one of the basic math formulas like Pi R squared is beyond me.
Post #38
https://my350z.com/forum/intake-exha...ormance-2.html
I expained this simple concept to you once already, and now others have to do the same.
AND 411Z you really need to hit the books. Being 21 and not knowing one of the basic math formulas like Pi R squared is beyond me.
Post #38
https://my350z.com/forum/intake-exha...ormance-2.html
I expained this simple concept to you once already, and now others have to do the same.
07-21-2008, 01:27 PM
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Originally Posted by gambino
Well we discovered the problem! The company uses an all wheel dyno with 2wd and 4wd settings. They forget to set the dyno to 2wd this last time so the numbers were off. I am going to try to get the car back in this week for a dyno for more accurate numbers
.
07-30-2008, 09:17 AM
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glad to hear you got the problem figured out, Is their anyway you could do me a favor and take a picture of your exhaust from the back with the folded rear bumper? maybe from a few other angles too? Im curious because right now I have a JIC single and someone local wants to trade for his HKS Hi-Power but Im not sure what it will look like with the fold! Thanks, I appreciate it!
07-30-2008, 10:55 AM
#57
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FYI: to all after the intake temp sensor reads above 96 degress the ecu will start to pull timing to prevent detonation.
School is out for the day go home.
School is out for the day go home.
07-31-2008, 10:45 AM
#58
Originally Posted by WalkerT
FYI: to all after the intake temp sensor reads above 96 degress the ecu will start to pull timing to prevent detonation.
School is out for the day go home.
School is out for the day go home.
08-01-2008, 12:15 AM
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eventhough his calculations were way wrong... he has the main point somewhat correct. The 2.25 dual is approx 65% diameter airflow potential increase over the stock 2.5 midpipe. Granted this does not take into consideration the muffler, and as Chris said, does not take into consideration the mechanics of the way it flows.
Re-dyno with comparable temps before you invest money into "fixing" a problem that maybe not a problem. Plenty of people install aftermarket exhaust and do not lose much, if anything.
Only other possibility would be to check for any leak in airflow, not familiar with the HKS, but it is good to use a sealant when installing an exhaust.
Re-dyno with comparable temps before you invest money into "fixing" a problem that maybe not a problem. Plenty of people install aftermarket exhaust and do not lose much, if anything.
Only other possibility would be to check for any leak in airflow, not familiar with the HKS, but it is good to use a sealant when installing an exhaust.