I'm looking into the next best step to add to my WRX
I've been putting little money into driveability/ then a little into performance/ then a little into looks and now we're back to performance.

the only engine performance mod I've done is adding an HKS catback. Originaly I was going to get the HKS downpipe next.

Then I was offered a new AEM CAI for $100, so I thought about that, but then I read a thread about how intake systems only add performance by making you run lean and in spots the car runs rich and the only way it helps is with a 300hp+ system and you need a utec but it takes hours to program right for the intake, etc.

Also the guy I talked to from Alta Performance (they sold me my exhaust) suggested getting an intake, down pipe, BOV and EVC. now I know BOVs actualy hurt performance make you run rich unless you get a DV, and after reading that think on intakes I dont know if I want to invest in one of those.

so now I'm back to the downpipe, is the HKS downpipe worth getting? and or is there some other performance mod I should do/get instead?

 

from what I've read about up pipes I like ones that have a flex joint and does not have a cat. What's the best one? Whats the cheapest one?

Also I'm most interested in power down low (Cause I'm going to autocross this thing) I've head a lot about how new headers will reduce low end power, will a new up pipe reduce the low end too?

 

Cheapest uppipe is $119
here - http://www.ravspec.com/pdetails.asp?itemID=778

Best uppipe (in my opinion) is the APS for $273
here - http://www.aps-wrx.com/wrx/my01/up_pipe/up_pipe.htm

An uppipe will increase your low end torque and allow your turbo to spool up quicker.

 

thanks mat!

I've looked at the APS before and must say it is a beautiful piece of piping...

Does anyone know how the APS up-pipe stacks up against the MRT up-pipe?

 

I personally think that you can do a step above the HKS DP, because it does not have a full bellmouth design and it does not even have a semi bellmouth design. The pipe and any gains you get from it will only be due to the removal of the 2 cats. BTW the Helix dp is 295 shipped from gruppe-s and its quality is IMO the best for the $ jus my .02

 

there's lots of DPs that have the separate outlets by the turbo what what actualy proves that it's a good design?

 

the flex joint in the up pipe is a must have for me... I live in a very cold area so the temp will be going from extreme cold to extremem hot on the up pipe which is the situation that the flex joint helps. I'm not about cheep power I'm about RELIABLE power.

MBC is right out. Dont know just seems like the most boot piece of equipment I could possibly put on my car. I'd rather save up servarl hundred bucks and get a piece of electircal equipment to manage my boost. Becides I'm looking LOW END POWER. meaning below 35K. upping the boost does minimal help down there.

the only things I've found reporting mor power on the low end are: UP-PIPE, DOWN-PIPE, RAM-POD Intake.

I like APS's uppipe and until some one proves technicaly why that's not the one to get... same goes for MRT's ram pod intake (based on my research CAI's are complete junk)

whats the most low power making down pipe I still dont know. I do know I dont like HKS's DP. does anyone know anything about the Kakimoto DP? where can I get it, how much is it, does it have a bellmouth design? etc.

 

Okay you want torque. First, intakes are a waste of money. You have a perfectly fine intake in your car, you just need to cut the fat. Take out everything including the airbox, drill some small holes on the frame of the lid, and zip tie the panel filter to the lid of the airbox. Bam, you have your short ram that appears stock. Also, you feel a difference, you'll get some sound, and I doubt the car will run lean because your using stock equipment. Now if you want more ( because that will give some difference but maybe not enough for you) you'll have to graduate to the bigger mods. I don't believe any type of exhaust part will help you, since your looking for it under 3,500 rpm where the turbo is not a factor. Having better flow and decreasing the back pressure will only give you turbo lag in that range, while giving you lots more power where you boost. You need that back pressure for low end. SO look at underdrive pulleys (not the most reliable, but they will make the power. Note: The stock pully has a harmonic dampaner, make sure you find a pulley that has this, or you talk to a professional about using this, other wise you will basically shake your engine apart). Also, to increase toque, you can simply put on smaller tires/rims. The smaller they are, the more the torque (since torque is a measurement of an objects rotational ability/power, the shorter the radius of the wheel, the more torque there is). Hope you found this at least as imnformative as it was entertaing to write it. Peace

 

A manual boost controller is a cost effective upgrade. Most spring/ball type MBCs actually offer boost at lower RPMs. I'm not a fan of MBCs for a daily driver, they keep the wastegate closed all the time, also effecting fuel economy negatively. I've heard that there's an electronic boost controller for the WRX avail. from a source that will only close the wastegate to the preset amount of boost when a preset amount of throttle is applied. I think this is great. Also it's a good example of owning a "mass produced" car that people modify. I couldn't dream about something similar for my 944 turbo... Anyway freeing up the exaust after the turbocharger in any turbocharged car will yield more power throughout the rev-band as well as better spool up. Headers that are optimized for high end power will tend to be 4 into 1 design. These only hurt low end power because they do not deliver the exaust gasses at a high velocity (to the turbo) thus hurting low end torque. Well there are other reasons (such as exaust scavenging) but that's for another post...

However, almost anything you do to the suspension will help your auto-x times more. If you really care about your auto-x times, go with tires (r-compound) and alignment before spending a dime on engine modifications. If staying in a stock class is a concern, this is where you stop. If not, you can go with a set of coilovers with agressive spring rates, sway bars and wider wheel/tires. Also, the ability to rev a bit higher may help you on a course/turn where staying in a particular gear would be beneficial, I've heard that the valvetrain in the american spec WRXs can handle 7500rpm safely, modifying the engine control unit can help with that I'm sure.
Ahmet

944 Turbo
944

 

I would get the HKS Uppipe and downpipe. You do not need the bellmount downpipe unless you are running large amounts of boost. Unless you plan on replacing your turbo and running lots of boost you can't beat the price per HP gain with HKS downpipe. At $170 shipped it can't be beat. I believe Z-1 Performance was running a special on HKS Downpipe for $170 shipped.

https://www.i-club.com/forums/showth...threadid=10774

thanks,
Greg