# 04 400hp with no mileage loss?



## novolvo (Jul 27, 2005)

What do ya 'spose it would take to get an 04 to 400rwhp without hurting the mileage any? Would a K&N, a MAF sensor and a tune get a guy close? I just feel so inferior pulling up next to my buddy's 05  I'd hate to have to get any more severe and starting hurting the mileage though...


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## John Millican (May 31, 2005)

Those mods are only good for about 20rwhp so you're still about 80hp shy. Don't change the factory MAF, it's fine as is.

The only way to get 400rwhp in an '04 and retain gas milage is with a power adder like Magnacharger, procharger or STS turbo.


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## diverdan (Apr 27, 2005)

Bear in mind that the '05 doesn't have 400 rwhp, that is the hp at the crank. It realistically has 350-360 rwhp stock. To get your '04 to that level a CAI, mild cam, and a tune would probably do it; adding headers would definately put you over the top.

To get 400 RWHP would be more in the realm of new heads, cam, LT headers, and a tune; or, as stated, some sort of forced induction (supercharger or turbo).

None of this should serious affect gas mileage as long as you keep your foot out it most of the time.


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## novolvo (Jul 27, 2005)

John Millican said:


> Those mods are only good for about 20rwhp so you're still about 80hp shy. Don't change the factory MAF, it's fine as is.
> 
> The only way to get 400rwhp in an '04 and retain gas milage is with a power adder like Magnacharger, procharger or STS turbo.


I appreciate the help, but I'm a little confused. K&N advertises their intakes to be good for 18.xx hp all by themselves on the 04 specifically. Won't a tune add 15 on top of that? Does everyone agree changing the MAF is worthless?

The 04s are 350hp stock, right? Leaving (at most) 30hp to go after the above mods.

I'm not trying to be argumentative, I'm learning about all of this as I go  

And I really do appreciate the comments...


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## novolvo (Jul 27, 2005)

diverdan said:


> Bear in mind that the '05 doesn't have 400 rwhp, that is the hp at the crank. It realistically has 350-360 rwhp stock. To get your '04 to that level a CAI, mild cam, and a tune would probably do it; adding headers would definately put you over the top.
> 
> To get 400 RWHP would be more in the realm of new heads, cam, LT headers, and a tune; or, as stated, some sort of forced induction (supercharger or turbo).
> 
> None of this should serious affect gas mileage as long as you keep your foot out it most of the time.


I see now the error in my thinking...rear wheel vs. crank.
At any rate, your advice is quite helpful. Any thoughts on cams to look at?
Thx! :cheers


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## RiceEater (Jun 21, 2005)

Yeah, stock 04 gets around 300 rwhp and 05's typically run around 350rwhp... so you dont need to get to 400rwhp to match up to your friend.


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## diverdan (Apr 27, 2005)

novolvo said:


> K&N advertises their intakes to be good for 18.xx hp all by themselves on the 04 specifically. Won't a tune add 15 on top of that?


You have to be careful with the power gains claimed by various bolt-on parts manufacturers. The numbers are very optimistic and are probably not what you would see in actual use. Alot of these bolt-ons acheive those great gains when they are placed on non-stock motors that really need more airflow that the stock system provides. If in doubt about a particular part, I would look carefully at the supporting info a manufacturer provides regarding how they got the numbers they claim.

Also, you can't just add the HP increase numbers of bolt-on parts to see what you would get (ex. CAI 15hp + Cat back 15hp + New Throttle body 15hp = 45 HP gain = 395 hp motor): the parts all help but their gains are not linear and independant of each other. In the above example your total gain might really be 20hp or so. 

A tune would benefit a stock car at least by leaning out the AF mixture some; its debatable whether it is worth the cost for stock. However, a tune becomes more beneficial as you add things to the car (CAI, headers, cam) because then you can make more significant adjustments to the program to take advantage of the flow of the new parts.

I hope this helps.


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## westell (Oct 4, 2004)

My goat is now a pig for fuel, after the cam package.

I swear, I can see the gas gage move.

Computer shows consumption down to 2.0 - 2.5 mph on hard accel :rofl:


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## fergyflyer (Apr 18, 2005)

On my 02 Z28 with a Corsa Cat-back (Mfg. claims 15hp) an LS1 Motorsports intake (Mfg claims 10-15 hp) and a good tune, I gained 20 hp at peak. The difference is the powerband at low and high rpms. Looking at 3000 rpms I had 32 more hp than stock, and looking at 5600 rpms I had 28 more hp. My fuel economy did not change at all with the mods. 

Don't mess with the MAF sensor. The stock one works great.


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## Camshaft (Jul 27, 2005)

Assuming you don't gun it at every stop light, more air flowing into the intake and out the exhaust can actually boost MPG, right? Or is that another K&N urban legend? It makes sense...a better air/fuel mixture should make you more efficient, right? If i'm wrong, someone set me straight, please...


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## JWCACE (May 12, 2005)

*K&N*

Is any body really satisfied with the K&N? I want more power cheap like everbody else.


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## westell (Oct 4, 2004)

Yes. This is 3rd car I've had K&N CAI on. All increases consistent :cheers


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## Rob (Aug 7, 2004)

I still get the same mileage after my cam change. Actually its better than stock after tuning. Even better running lean cruise. [email protected] tank average  Mixed driving nets me around 21-23mpg.


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## IPOCKALYPSE (Mar 7, 2005)

I installed a K&N CAI and then had it dyno'ed and got 308RWHP; my friends stock 04 put down 301RWHP. I can't say for sure if it really helps because I didn't dyno my car stock but, I believe that the RWHP difference was from the K&N.


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