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I've done some poking around trying not to ask the same newbie questions everyone asks, but here goes anyway...

I just got an 07 IS250AWD, and I was really on the fence between the 250AWD and the 350. In the end I got the 250 knowing that I would need the AWD at some point and already have in the 2 months I've owned it. Living in the Northwest AWD is really a necessity every so often.

Anyway to get more power it sounds like I can mod the intake and exhaust correct? Are there headers for this engine as well? All that being said are these mods even worth it on this car or are the OEM parts pretty decent as it is? Are there any other mods worth mentioning to get more power out of the 2.5L?

Also why don't they make a 350AWD model? Even if it would have been an extra 3K+ I'd been all over that, sigh...

Thanks!
 

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An AWD IS350 would be more than 3k more... and most likely they don't want to canibalize AWD GS sales.

There's really nothing worth doing to your 250 that'll add enough power to justify the cost.

Intake might add 3-5 horsepower if you're lucky (and if you wanna do this, just save your $ and get a Joe Z pipe, it'll add as much as anything else will and be cheaper)

Exhaust, assuming you want to remain emissions legal, might add another 5 and cost massively more. If you don't care about emissions you can spend over $1000 and get an exhaust that might add 10 hp.

There are IS250 headers but there your choices are either insanely priced (Jun-TW) or less expensive ($650) but completely illegal emissions wise and you'll have a check engine light all the time currently (Mazurri)

The ISx50 just isn't a very mod friendly car as far as adding much power affordably while keeping everything else good. Excluding the AWD issue the cheapest way to add power for the money to an IS250 is to trade it for an IS350... and the cheapest way to reliably add power to the IS350 is to get an IS-F.
 

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Discussion Starter #3
Thanks for the info. I'm not displeased by the power of the 250 and truth be told more power / speed would only help me get into trouble. Thanks again for the input :)
 

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good advise but, but i have made good power with just an intake, headers an a cat back exhaust. intake gave me 8hp and 10tq. headers gave me 5hp and 6tq. tq is what u need to move ur car.
 

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Given the only headers in existence for the ISx50 right now that don't cause a CEL are the Juns, and they cost $1700, I'm not sure how a gain of 6 torque for $1700 is anything approaching decent. Add that any intake besides Joe-Z will run another $300 and you're at 2 grand for a gain of 16 torque (and I don't buy that you gain 10 tq from an intake, since that's 2-3 times more than anyone else on earth ever has)

For ~$3000 you could've just got an IS350 and gained 92 torque.
 

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jun claims with headers only, dynoed 225rwhp the reason no CEL is the high flow cats,any exhaust shop can do that for you on mazzuri set up.195rwhp for mazzuri
 

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IMO, any of the performance parts for the 250 will give it nothing but
a personal touch.
the gains from these mods are so tiny. They may, at best change the delivery of what you already have. but as far as power gains, you will be lucky to notice any... Saying that, I have an intake, and i'm looking for an exhaust..., just to personalize it a bit. But i think the money is worth it in that respect.
Good luck with what ever you choose.
 

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IMO, any of the performance parts for the 250 will give it nothing but
a personal touch.
the gains from these mods are so tiny. They may, at best change the delivery of what you already have. but as far as power gains, you will be lucky to notice any... Saying that, I have an intake, and i'm looking for an exhaust..., just to personalize it a bit. But i think the money is worth it in that respect.
Good luck with what ever you choose.
Not true at all.
 

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I have my header on my IS250 right now, the extra 30 pounds of TQ help me everywhere.. normal driving, going up hills, not having to gas it as much. I get ebtter MPG now also. I definitely notice it, in every rpm.
You got 30fpt from a header ? How much did that cost you?
Did you notice a difference in the low end?
And what are you using for the balance of your exhaust?
If you can get that I would say it's probably worth it...
 

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He's the one who makes em.

Way cheaper than Jun-TW too.

Downsides are no cats and it currently sets a CEL.

If he fixes the second problem then it'd be the first "worth it" upgrade I've seen for a 250 so long as you never have to pass an inspection. (if he fixed the first too it'd be worth it across the board but he's suggested he has no interest in providing any sort of bolt-in cat solution)
 

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He's the one who makes em.

Way cheaper than Jun-TW too.

Downsides are no cats and it currently sets a CEL.

If he fixes the second problem then it'd be the first "worth it" upgrade I've seen for a 250 so long as you never have to pass an inspection. (if he fixed the first too it'd be worth it across the board but he's suggested he has no interest in providing any sort of bolt-in cat solution)
Theres always a catch...I'm not saying it's not possible, but from what I've seen with the 250 so far, simple bolt on's don't give you a great deal of power.
 

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You got 30fpt from a header ? How much did that cost you?
Did you notice a difference in the low end?
And what are you using for the balance of your exhaust?
If you can get that I would say it's probably worth it...
I make them my self. Welcome | Mazzuri Super - custom mandrel bends,mandrel bends,stainless steel mandrel bends,45,90,180,120,15,u bends, mild steel mandrel bends . They are not for sale yet, as I am still working on a CEL solution.

Here is a dyno sheet http://www.mazzurisuper.com/images/is250_dyno.jpg you can see the low end gains.

I am not sure what you mean when you say "balance of your exhaust?"
 

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I make them my self. Welcome | Mazzuri Super - custom mandrel bends,mandrel bends,stainless steel mandrel bends,45,90,180,120,15,u bends, mild steel mandrel bends . They are not for sale yet, as I am still working on a CEL solution.

Here is a dyno sheet http://www.mazzurisuper.com/images/is250_dyno.jpg you can see the low end gains.

I am not sure what you mean when you say "balance of your exhaust?"
Pretty impresive gains. What type of muffler, dia. of tubing...No cats?
Are there any other mods or is this a bone stock engine ?
 

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big willy what have you seen?:pissed: Jun-tw dynos 238rwhp from headers and straight exhaust.I have chosen to go with mazzuri for reliabilty and with my custom exhaust my #'s will be close too Jun.when I order from daniel I will dyno before and after.
 

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big willy what have you seen?:pissed: Jun-tw dynos 238rwhp from headers and straight exhaust.I have chosen to go with mazzuri for reliabilty and with my custom exhaust my #'s will be close too Jun.when I order from daniel I will dyno before and after.
I don't have much experience with this motor but it is still a internal combustion engine. Pumping more air in and out is what it is all about.

As far as bolt on parts that make big power, I havn't seen much for this car.
And there is always the issue of making power without lossing realiablity. If we are building a race car, and throw out emisions and all that, we can probably make some good power by opening up the air flow. ie...intake, heads, exhaust.
Anyone using NOS? Again though, this get's into re-programing the ECU and so on.

I've built many american V8's with big power, (upwards of 800-1,100 hp) and a few 4cyl. turbos.
Don't get me wrong, the stock exhaust on this car looks like someone ran over it in the driveway...but, you could put a strieght free flowing exhaust
on but unless the heads, cams, ect... are capable of flowing that kind of air,
It's not really a useable mod...is it?
 

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So I guess dynos are not correct.I will perform before and after dyno's once I get my set.
 

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So I guess dynos are not correct.I will perform before and after dyno's once I get my set.
Dynos are best to get real numbers and like I said if you are truly getting
30 Ftp that's a good number on a stock engine...
but it's far from a big number for what your doing to the car...and when you do your dyno numbers let us all know where to get our cars inspected with no cats.
 

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There's a guy on CL using Nitrous on his IS350...pretty damn good gains for just the 65 shot he's running (and that's with the stock ECU)... not a risk I'd take with an engine under warranty though.


For folks who need to pass inspection w/headers Jun-TW is the only option right now, and not a very good option for 350 owners since all their stuff was designed/tested for a 250.
 
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