450 whp?

[Pullsti]

Hey there,

So I've done some mods on my 2015 STi, and I'm hesitant to get a built motor because it's always seemed a bit extreme. But curiosity is getting the better of me.

I'm basically looking to ask, if I did get an engine build, since there are so many levels of "builds," what would I need done to safely reach ~450 whp without expecting a blown engine after 10,000 miles?

Here are the mods I've done so far to drivetrain:
AEM cold air intake
Cobb Turboback Exhaust
Cobb 1000 cc fuel injectors with upgraded fuel pump, fuel pressure regulator
Grimspeed TMIC
Turbo smart external wastegate (still have stock turbo)
Cobb Boost control solenoid
Grimspeed up pipe flanged for 44mm external wastegate
Perrin transmission mount
Perrin Pitch stop mount and pitch stop brace
IAG Street series Air Oil separator
Eibach 22mm rear sway bar with upgraded endlinks.

So what kind of engine build mods would I need to "reliably" be able to get a tune for ~430-450 whp? I know the reliability part has a lot to do with how I drive it. I'd be looking for some spirited and fun driving whenever I can, no WOT in 5th or 6th gears, minimal WOT at low RPM. (After just over 2 years, I've barely ever gone WOT but I do have a heavy right foot for sure).

Thanks!

 

[IGOTASTi]

[MENTION=6188]Pullsti[/MENTION] welcome friend.

Great questions!

Do you have a reputable engine builder? A lot will be based off that.

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[Pullsti]

If I do get an engine build (big if) it would be by RT Tuning in Montgomeryville PA. They've done all the other work on my car including my custom tune. And I see cars on social media with built engines by them all the time. As far as I know they are an awesome speed shop, as has been confirmed by reviews I've seen and interactions with everyone I've met there who's had work done on their card while I was also waiting on my car.

But assuming they are reputable, what kind of engine "builds" would I need? Pistons, crank, just what exactly? And what kind of cost should I expect?

 

[FL4TTURBO]

Google 'IAG staged closed deck builds'. Look no further than that. If you're going to spend the money spend the money one time and forget about it. My best advice to you sir.

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[HolyCrapItsFast]

Are we talking Pump or FlexFuel?

A turbo is the one thing that will do the most to get you to 450WHP. No matter what else you do, 450 is a tall order with a stock turbo and, dare I say, impossible unless tuned with E85. Beyond that some supporting mods will help round out the build. What I would add to what you have already done is...

TGV deletes
FlexFuel Kit (optional)
Headers
Big MAF intake (or a speed density tune)
Fuel Pump (Aeromotive 340 or better)

Also the stock block will handle up to 450 for quite some time so you might consider leaving the stock motor for now and save up for the inevitable moment it does take a shit later on. The issues are largely due to improper tuning strategies and lack of maintenance. My last motor had 85,000 miles on it with over 430 WHP its whole life. I decided to take it out and replace it with a fresh motor and upon inspection I noticed that it was no worse for wear. I could have driven it another 50,000 miles no problem. The new motor is also a stock block and is now tuned to 444 WHP. I am having allot of fun with it!!! :lol:

 

[Raven32]

[MENTION=6188]Pullsti[/MENTION], welcome to the Forum. If theres one person here I had to listen to when it comes to selecting parts etc it would be [MENTION=9]HolyCrapItsFast[/MENTION]. He has a deep understanding of how the ECU's interact with our cars and what can and cannot be done through experience. Since there has already been some sound advice here, let me ask you why are you looking for 450 HP? Any particular reason?

 

[FL4TTURBO]

If I do get an engine build (big if) it would be by RT Tuning in Montgomeryville PA. They've done all the other work on my car including my custom tune. And I see cars on social media with built engines by them all the time. As far as I know they are an awesome speed shop, as has been confirmed by reviews I've seen and interactions with everyone I've met there who's had work done on their card while I was also waiting on my car.

But assuming they are reputable, what kind of engine "builds" would I need? Pistons, crank, just what exactly? And what kind of cost should I expect?

Do you have any pics of your car?

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[Grinder34]

Remember, with 450 WHP, there are going to be driveability differences. As Holy said, you'll need a bigger turbo. Bigger turbos take longer to spool up, so you'll basically be N/A in normal city/highway driving. Then with 450 WHP most people end up with a FMIC with lots more plumming, leading to some turbo lag. And since you're pushing the motor harder, IMO maintenance/check-ups are more important. So you'll want to do UOAs, visual inspections, logging etc... more often. As Holy said, the stock block can take it, but you're still more likely to run into a problem leading to a major bill on top of the bill to get you to 450 whp in the first place.

Not that 450 WHP isn't an amazing time, but make sure you're ready for what you get!

But to build on what Holy said, you'll need (someone please correct me if i'm wrong!):
Turbo (may require EWG)
Injectors
Fuel Pump
Tune
Intercooler (FMIC, Better TMIC, AWIC)

You'll want:
New turbo-back (IIRC the Cobb necks to 2.5")
Headers
TGV Deletes
Turbo Inlet and MAF
Phenolic Spacers
Wideband O2 for logging
Gauges (some combo of: boost, oil pressure, oil temp, EGT)
*suspension!! (not for power of course, just to *match* the upgraded power)

 

[Raven32]

Remember, with 450 WHP, there are going to be driveability differences. As Holy said, you'll need a bigger turbo. Bigger turbos take longer to spool up, so you'll basically be N/A in normal city/highway driving. Then with 450 WHP most people end up with a FMIC with lots more plumming, leading to some turbo lag. And since you're pushing the motor harder, IMO maintenance/check-ups are more important. So you'll want to do UOAs, visual inspections, logging etc... more often. As Holy said, the stock block can take it, but you're still more likely to run into a problem leading to a major bill on top of the bill to get you to 450 whp in the first place.

Not that 450 WHP isn't an amazing time, but make sure you're ready for what you get!

But to build on what Holy said, you'll need (someone please correct me if i'm wrong!):
Turbo (may require EWG)
Injectors
Fuel Pump
Tune
Intercooler (FMIC, Better TMIC, AWIC)

You'll want:
New turbo-back (IIRC the Cobb necks to 2.5")
Headers
TGV Deletes
Turbo Inlet and MAF
Phenolic Spacers
Wideband O2 for logging
Gauges (some combo of: boost, oil pressure, oil temp, EGT)
*suspension!! (not for power of course, just to *match* the upgraded power)

Looks Good to me. i pretty much have all this cept i am running true 3" turbo back for exhust with internal Waste Gate.
Additionally. I run the following guages:
Oil Pressure
Boost
Air to fuel Wideband with logging (AEM UEGO)
Exhaust Gas temp Gauge Tapped on #4 runner.

Gauges are important because you can use them to get an idea of where to look for issues with your motor. For example I keep a regular eye on my oil pressure gauge to know when my engine is fully warmed up. At start up its at 100+psi at 3/4 warmed up it sits at 60 PSI and when its fully warmed up at idle it sit at 35-40 PSI. If I ever see the pressure drop below what this I know there is a major issue with my oil system. Now this is just one example.

Additional gauges that might be useful are Fuel pressure, oil temp, knock, and Intake air temp. I could use fuel pressure to monitor how much gas is getting to my injectors at any given time with out use of a laptop, I.E. if fuel pressure ever drops below 43.5PSI +current boost i have an issue. Oil temp would be helpful during track days by letting me know when to back off, so I don't kill the motor when doing prolonged runs at full tilt. Knock gauge would allow me to keep an eye on knock and if i start to see patterns I could use the laptop to capture what is fully going on. Intake Air temp could tell me if I am getting ridiculous amounts of heat soak from engine bay.

My first three gauges were Oil pressure, boost, and Air to Fuel. From there I got a Voltage gauge, part of my turbo timer, and an EGT gauge. Where you go from there and what gauges you want are entirely up to you, and what you want to keep an eye on. Just don't by cheep gauges like an Air to Fuel that gets it reading from the ECU. While it looks cool it serves no real propose that I can think of because it is not 100% accurate.

Mind you these are just examples of the use of some of the gauges, but a tool is only as good as the person using it.

As far as mods go just take your time and think about each aspect of your build. After that try to imagine how each part will work separately and then how it will complement other parts of the car. I say this because it will help you understand how everything works together and help you get the bigger picture. That being said, I personally am not after any particular HP/Trq numbers, where my car lands it lands. For me its more about feel and reliability than anything else. Well that and my small pocket book.