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Discussion Starter · #1 · (Edited)
I will be fully bolted shortly to include an Intake, Ported & Polished Intake Manifold and Throttle Body and Catless headers... I'm either going to put on a catless exhaust or I'm going to keep the stock exhaust and put on electronic cut outs. This thread will most likely determine which path I choose. I'm am looking for the highest, reliable horsepower possible. Here are my questions:

1- Will the IS-F's N/A 5.0L motor have enough back pressure to run properly if I run the cut outs directly after the O2 sensor in the headers?

2- Will cut outs yield a higher horsepower than a 2.5 inch catback with no cats?

3- Will the constant opening and closing of the cut outs have any affect on the ecu and not allow the car to run at it's greatest potential, as the cut outs would be installed after the O2 sensor?

4- Being that the headers will come with an electronic trick to prevent a CEL, wouldnt the O2 sensors be getting the same voltage all the time, thus eliminating any differences and the potential problem of #3?

Thanks
 

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Discussion Starter · #2 ·
Does anyone know the answers?
 

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Sorry brotha, I'm not ignoring you, I just got no clue. I guess the easiest way to find out is to unbolt and give it a run without the exhaust. If I get around a dyno I'll give it a go, but it may be some time before I get a chance.
 

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Discussion Starter · #4 ·
I appreciate the response. I just went ahead and purchased an ISS Forged exhaust. Thanks
 

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Discussion Starter · #6 ·
I'm going to DYNO at Cobb in Plano most likely at the end of next month. Their DYNO would be a VERY fair DYNO as it's compared to a lot. I'm hoping for 425+ whp! Fingers Crossed!!!

Also, does anyone know where I can pick up some Random Technology 2.5" high flow 100 cell cats, or equivalent, for cheap?
 

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I hope you hit 425 or more..do you have a baseline?

I'm getting a baseline with my K&N on tomorrow. After that, I'll get the PPE headers put on, drive around, see if how loud it is and may get an exhaust and re dyno. Going on a heart breaker Dyno-mite dyno

did you get the extrude hone intake second hand, saw an add on ebay and club lexus a couple months ago.
 

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Discussion Starter · #8 ·
It's brand new. I bought from someone who purchased it new but never installed it.
 

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Finished by baseline with the KN

374.5hp 338.7 tq pull 1
378hp 338.5 tq pull 2
377.7hp 348.6 tq pull 3

the dyno yields 3-5% lower than a dynojet

I guess the KN adds 20-30?

will wrap the KN add headers and redo the pull hoping for 410

You should be hitting 420+
 

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Discussion Starter · #10 ·
Awesome... That's why I won't back off from the K&N being the best intake... Period. Was this a Mustang DYNO?
 

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Discussion Starter · #12 ·
Good numbers... You hear anything about the headers yet?
 

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Discussion Starter · #14 ·
Thanks... Never been there but I've heard good things.
 

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Thanks,

I called and they said the first batch will be off to get coated soon....didn't really pay attention to details about the first batch, I think I'm in the second batch which be sent off for coating around then end of next week. Hoping to get mine sooner to book an install before heading to the drag and a track day.

I'll have baseline drag times by June1st with post header times by 6/15. Thunderhill day set for 6/17.


Good numbers... You hear anything about the headers yet?
 

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Discussion Starter · #16 ·
Sounds good. Unfortunately I'm in Lubbock TX, out in the middle of nowhere and at 3,500 above sea level. Soo getting the headers installed, doing dynos, and hitting a drag strip basically requires me to go to either Dallas or San Antonio. Sucks. I'll prob be moving to Houston within the next year and a half. I can't wait.
 

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Given how consistent the ISF's output is, you'll probably have similar power to others anyhow. There must be a lot of open room in Texas to open it up.

Sounds good. Unfortunately I'm in Lubbock TX, out in the middle of nowhere and at 3,500 above sea level. Soo getting the headers installed, doing dynos, and hitting a drag strip basically requires me to go to either Dallas or San Antonio. Sucks. I'll prob be moving to Houston within the next year and a half. I can't wait.
 
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