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Why am I losing power???

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Old 07-16-07, 10:35 AM
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iizzle3fiz
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Default Why am I losing power???

Lexus IS250/IS250-AWD /IS350: 2006 IS350

Which Exhaust: HKS Hi-Power

Dyno: Stock 260.0 HP/232.1 ft-lbs
w/K&N Typhoon 261.1 HP/239.0 ft-lbs (gained 7hp in the midrange)
w/K&N Typhoon and HKS Hi-Power 247.9 HP/220.4 ft-lbs (loss 13 HP/19 ft-lbs)

Did you feel any Hp/Tq difference, if yes, how much/where in the powerband, ect? Yes...I'm pissed off my car got slower!

Comments on your exhaust: I picked HKS Hi-Power because i like the look and the sound. But i am very disappointed in the performance of my exhaust. The combination of intake and exhaust sound really good but i can really feel the loss of torque from 2-5k rpms. I added all the upgrades the same day (saturday) so it cant be the temp or weather that caused the loss.

Last edited by javyLSU; 07-16-07 at 05:34 PM.
Old 07-16-07, 10:46 AM
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Gernby
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Originally Posted by iizzle3fiz
Lexus IS250/IS250-AWD /IS350: 2006 IS350

Which Exhaust: HKS Hi-Power

Dyno: Stock 260.0 HP/232.1 ft-lbs
w/K&N Typhoon 261.1 HP/239.0 ft-lbs (gained 7hp in the midrange)
w/K&N Typhoon and HKS Hi-Power 247.9 HP/220.4 ft-lbs (loss 13 HP/19 ft-lbs)

Did you feel any Hp/Tq difference, if yes, how much/where in the powerband, ect? Yes...I'm pissed off my car got slower!

Comments on your exhaust: I picked HKS Hi-Power because i like the look and the sound. But i am very disappointed in the performance of my exhaust. The combination of intake and exhaust sound really good but i can really feel the loss of torque from 2-5k rpms. I added all the upgrades the same day (saturday) so it cant be the temp or weather that caused the loss.

I know this post isnt for all this so i'll start a new post to get some help on this.
I think you got a bogus dyno test. I don't believe there is any chance that the HKS Hi Power exhaust could be working that poorly for you. If your car feels slower, then I would blame the K&N when the hood is down. I realize the K&N has a heat shield, but it isn't sealed.
Old 07-16-07, 10:50 AM
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iizzle3fiz
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All things the same....on the dyno...hood open and fans blowing directly on intake. we did a baseline with no upgrades, then we added the intake and made power (7hp in the mid and 9 ft-lbs on the top)....then pulled the carr off the dyno to install the exhaust....30 minutes later back on the dyno and lost major power. We even added an extra fan because we could believe it was losing that much power.
Old 07-16-07, 11:00 AM
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Gernby
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Originally Posted by iizzle3fiz
All things the same....on the dyno...hood open and fans blowing directly on intake. we did a baseline with no upgrades, then we added the intake and made power (7hp in the mid and 9 ft-lbs on the top)....then pulled the carr off the dyno to install the exhaust....30 minutes later back on the dyno and lost major power. We even added an extra fan because we could believe it was losing that much power.
Unless your exhaust is defective and has a blockage, I still think it was a bad test. First off, those gains that you got from the K&N intake will go away when you close the hood to drive on a street. Second, I really doubt I could have gotten a 13.1 sec at 105 MPH in the quarter mile if my HKS Hi Power was robbing 10+ rwhp.
Old 07-16-07, 11:21 AM
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caymandive
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Dyno testing should not be used as the sole means of measuring gains. Heck even Gernby showed a loss in power after his exhaust work.
Old 07-16-07, 11:39 AM
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iizzle3fiz
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gernby, i saw how fast u ran and that helped me decide on HKS (besides the look and sound). i agree that it should not be losing 12hp and 19 ft-lbs and thats why i was so disappointed. although with my hood down the gain from my intake will be minimized, on the dyno all factors were the same.

caymandive, both the dyno and the seat of my pants say i lost power. i really feel the loss in the mid range and throttle response is less.

one thing we did not do is reset the ECU....do u think i should reset and go back to the dyno?
Old 07-16-07, 12:01 PM
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Gernby
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Don't reset the ECU. It will adjust its maps on its own if it hasn't already. If you are certain that it is slower, I recommend pulling the exhaust off to verify that there are no obstructions in the pipes and the gaskets are well centered. It should be a super simple job to do yourself if you have some rhino ramps.
Old 07-16-07, 12:30 PM
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RocketGuy3
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iizzle, you're not using the silencer inserts by any chance, are you?

That would be very disappointing to hear otherwise. I haven't felt much difference one way or another, but I would hate to know that my exhaust could actually be reducing power...
Old 07-16-07, 12:37 PM
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i called HKS to ask about why i lost power. i was told that it could be due to the intake...they say they only tested their exhaust with a stock air box and with the increased air and loss of back-pressure, i could be losing power.

i think that is crazy because if i get more air in and should want to get it out, right?

i will check the installation when i get home but i took it to a very reputable shop here in houston for installation/dyno.
Old 07-16-07, 12:45 PM
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Originally Posted by iizzle3fiz
i called HKS to ask about why i lost power. i was told that it could be due to the intake...they say they only tested their exhaust with a stock air box and with the increased air and loss of back-pressure, i could be losing power.

i think that is crazy because if i get more air in and should want to get it out, right?

i will check the installation when i get home but i took it to a very reputable shop here in houston for installation/dyno.
RocketGuy's question about the silencers is a good one. Silencers could easily reduce power by that much or more. If you aren't sure, post a close-up picture of the tips.
Old 07-16-07, 12:45 PM
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iizzle3fiz
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no silencers...wide open!

sad to say that i dyno'd after each part install cause i wanted to see how much i would gain...never thought i would lookin at a loss.
Old 07-16-07, 12:46 PM
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i'll post pics tonite when i get home
Old 07-16-07, 06:25 PM
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caymandive
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iizzle3fiz, do you have some dyno charts you cold post? Possibly overlaid and with air/fuel?
Old 07-16-07, 09:25 PM
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My dyno chart....

Last edited by iizzle3fiz; 07-16-07 at 10:02 PM.
Old 07-16-07, 09:29 PM
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here is an exhaust pic...i don't think the HKS Hi-Power comes with silencers anyway and i sure didnt buy any.

Last edited by iizzle3fiz; 07-16-07 at 10:03 PM.


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