I raced a fully built WRX today which had a garrett GT-30 ballbearing turbo with the boost turned down to 6psi, and won ...it wasnt runnin at full potential (18psi), but hey, still a good feeling to beat a fully built car like that which dynoed at 270whp at the 6psi it was runnin on

 

DAMN, it dynoed at 270 at 6psi??? Any idea how much boost a stock WRX has?

 

I am pretty sure a stock wrx uses around 12-13 psi of boost

 

How do they dyno AWD cars?

 

There are AWD dynos. Local shop here as a AWD Mustang dyno. 1 drum for each wheel.

 

That probably feels real wild with all for wheels on rollers.

 

the most common way to dyno AWD cars is to disconnect the axle that goes to the rear wheels and dyno it like a FWD car. That's what all the guys with DSMs that I know do.

 

Then wouldn't that give them a higher HP/TQ reading then what they would be making with all four wheels?
I may be putting too much thought in to this, really...lol

 

technically...slightly higher, but it makes it much easier to compute driveline loss (standard FWD loss) and come up with a crank hp number.

 

the WRX was dynoed on a four wheel dyno at a shop here in SoCal

 

Dynoing that number on 6psi is VERY far fetched in not impossible. I suggest you check your numbers or your sources

 

whats so far fetched about that, my s14 dynoed 210 to hte wheels on 7psi pretty much stock with just a fuel pump, downpipe, and exhaust with the stock t25 turbo....I would think a fully built wrx with a GT-30 ball bearing turbo could make 270...

 

I think what he is saying is how the hell do you dyno that # with ONLY 6psi????, if it were only 6, it would be signifcanly less than stock, even with many many other mods (I/E/H, etc..).

 

its a much larger turbo than the stock turbo, plus the car is fully built...at full boost (18psi) the car dynoed like 400hp or somethin close to that

 

I am confused, I thought that the reason people got bigger turbos is to handle more boost, so whether the PSI was from a small turbo or large, it is still ONLY 6 psi (measured AFTER the turbo). My research with turbos is limited, but my wife has a modded Jetta 1.8t, and with the jetta, what I am talking about it how I understand it.

 

Well the reason 6 psi from one turbo can equal more hp than 6 psi from another turbo is effeciency. Effeciency refers to the change in air temp when "boosting" air. A smaller turbo will generally be less effecient because it has to work harder/spin faster than a larger turbo to create the same amount of boost. This extra turbulence causes the air temperature to be higher and in turn causes a loss of density. Of course we all know the benefits of cooler air. You are correct though, bigger turbos can handle more boost, generally. Smaller turbos, like the afore mentioned t-25, can make up to...oh, around 22 psi, but they are way over their rated effeciency at that point and pretty much stop gaining hp around 15-16 psi. At 22 psi it just becomes like a hair dryer and will cause detonation. On the other hand larger turbos may not hit their max effeciency rating until 22 psi. Those big diesel 18-wheeler trucks have giant turbos that hit max effeciency somewhere around 30 psi .

 

thanx for the clearification

 

Ah I only wish they had a AWD dyno in hawaii. I also own a 03 WRX, and most of the WRX owners here dream of a AWD dyno. I guess thats one of the disadvantages of living on a rock in the middle of the ocean. LOL

 

Vishnu Tuning Dyno

On a recent trip there, my 02 WRX made around 215 whp and even with conservative drive line losses is close to 300 crank HP. This is with a stock turbo and 15 PSI (running CA's pee water for gas -- on 100 octane the ECU really ramps up the timing and I run 16.5 PSi and would not be surprised if my car made 15-20 more HP!). I see no reason to refute the earlier claim regarding the 'fully built WRX'. Really radical WRX examples roam the streets of LA. :-)

Now, driving my 350Z and WRX could not be more different. In fact since buying my Z a few weeks ago, I've only driven my WRX once -- it actually rained here in Los Angeles. :-)

BTW, for those with WRX or EVOs, Shiv Pathik of Vishnu Tuning is a great guy and personal friend. He is a very knowledgable engineer and recommend him highly for anything.

 

why was it set only at 6psi?