Quote:
Originally Posted by Aladeenster
I guess you did not read what my post said. It says "for those of you running 20g turbos, what power have you seen and with what type of supporting modifications". So since you're new to comprehending, maybe you should go to some forum that specializes in understanding English. Thanks for your post doe. Greatly appreciated.
No, I read beyond the face value. You purchased a 20GTX and are concerned if it will hit 400whp. You want people to come in here and appease your concerns with stories of grandeur running their 20GTXs and making a billion hp with ease and no mods.
The reality is pretty simple though. There is no magic. Also, many people making significant power tends to show it off meaning most everyone that will reply and show their amazing dyno graphs and builds will already have a thread made showing exactly that. The information is already here available to you with the click of a few key strokes. This thread is just being lazy. I say this because there is SO MUCH information already there and so many people running and showing off their 20G builds. Yet, despite all that information already shared open to your viewing wonder you make a thread to have said people come to you to repeat the same information with no effort on your part. This is laziness.
Now I'd feel different if the data was hard to find, say you asking about some obscure turbo or strang build that no one's ever done or has done but simply has not presented measurable info. A simple example would be supercharger builds. That's pretty rare. That's harder to find and may warrant some input by people, YET that's also already been asked by others and responded by members. That too would be simple repetition of data that already exists.
I'm not trying to be cynical here, however a PILE of people run 20Gs and have a sea of 20G builds and dyno results. You starting a thread is a bit redundant and forces other people to respond to you and repeat themselves.
The answer for you lies in simple science. A 20G is a 47 lb/min (680 cfm) turbo. On a general level, you're looking at around 1.45 cfm/hp produced, so 680 cfm means about 470hp. Now this is crank hp, so there's some lost through the drivetrain, typically 60-70ish range for hp loss. There are several turbos around this output level as well as higher. They will produce 400whp on Subarus.
Yes, there are some supporting mods to allow enough fuel and air flow to actually make it all work, but that's all basic stuff and pretty easy to find by searching. There's tons of threads covering all the key concepts.
How about fuel?
Typically people just grab the Walbro 255 lpr bump and call it a day. Well how much HP does it support? Well, a lot of people use this pump so a lot of people have tested this pump. Tests indicate it's north of 500chp for any boost level you'll run. There's a pile of information on the internet. Look if you care.
What about injectors?
Again there's a pile of info online for this including easy to use calculators. 470chp with an 80% duty cycle comes out to around 925cc/min. Depending on the calculator used, this can be higher or lower depending up assumptions the calculator uses. A 1000cc/min injector is a pretty simple buy here and will offer plenty of flow without needing super high duty cycle to achieve it. You could run 850cc/min injectors at 90% duty cycle and achieve similar results. It's just commonly suggested to stay at 80% or below, although you can run higher. Some suggest 90%.
Are there any air flow mods?
Oh yeah, tons.
On a basic sense, once you get up into the 400hp range you do want to start stepping away from the small 2.4" intake. You certainly can't use the stock intake at all at this point, and a high flow 2.4" size starts to become restrictive. A 3" option is advisable but not needed. You will find 20G sized turbos in both sizes, although many will still be 2.4" sized. The 3" size starts to become more common once you're looking at GT30 sized turbos.
The intake manifold isn't exactly the highest flowing piece of hardware, but there's not a lot of great alternatives without paying big bucks. There's been flow testing on a variety of option, so look if you have interest.
You can also look at head work and cams too if you want, but it's not absolutely needed at 400hp. If you're doing 500-600hp, you really need to look at this.
Pre turbo, the exhaust size isn't as big of a deal. Small means fast and can help spool. Upgrades can improve flow though and aid top end hp while sometimes sacrificing low end spool. Mainly you just get rid of the cat in the uppipe and call it a day, but you can certainly do more. You can upgrade the header and uppipe to better products. The bigger part is the rest of the exhaust. The happiest turbo is the one with no exhaust at all, so big is good. 3" is typically, but don't feel bad about oversizing this. Low restriction is typically 115cfm per cubic inch of cross sectional area. This in general is considered "lossless" or of low enough loss that there is low gains for the amount of added cost or weight. Since we're talking a 680 cfm turbo, we're talking a 3" exhaust with nice, mandrel bends, and a high flow muffler that doesn't restrict that kind of flow level. We can certainly up size this some too. Bigger typically means louder though, and there's added weight to the size since it's normally made of steel. The weight's at least low in the car, but it's still a lot of weight. Some opt for titanium, but it's costly.
What about other things?
A lot of people change the boost controllers. The stock one is kind of slow. There's lots of options like Grimmspeed's EBCS that many run. Some run an affordable GM solenoid:
GM boost solenoid for Typhoon, GM Part # 1997152
Pigtails, GM Part # 12102747
Frankly there's tons of options.
Tuning is open source, so there isn't anything you need to do for the ECU.
Now nothing I've said here is hard to find knowledge. It's all rather quite easy to find in minutes. There's no magic, nothing new, nothing that hasn't already been said or shared. There's a pile of dyno results and build lists for a pile of cars running 20Gs and GT30s that will meet what you seek. They list parts upgraded and straight forward results. It makes it all a pretty easy to put together, fool-proof route for building a car just because so many people have already done it. All you have to do is look.
I am being slightly cynical actually but mostly because this is more a results forum section, not a section of inquiry, although it's done from time to time. This is more a "hey, here's my results" section. It's like going to a museum and asking how to paint.