I just dyno'd my silvia and the numbers were what i was hoping for, considering that its pretty much bone stock. I had 137hp @6800 and 119tq but what was not expected was the dyno recorded only 5.5psi max while i was told that the wastegate is set for 7psi. Even more odd is the fact that my boost gauge reads 7psi aswell.
Can anyone give any insight to what is happening?
Dyno'd and now down 2psi...
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rexhunta
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Re: (rico05)
Thats weird as, as my stock CA wastegate reads 9psi on the dyno... hmmm.rico05 wrote:Wait, do you have the stock turbo, or a SR turbo?
Stock wastegate is 5.5psi, and the stock wastegate for a SR T25 is 7psi.
Pete
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biosehnsucht
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its been known for stock wg's to sometimes boost more if you hve alot of intake/exh mods cause they just aren't strong enough to regulate it to their low psi setting..
where did the dyno source their pressure reading, and where is your wg and gauge sourcing?
if you're sourcing at the hotpipe and they are at the coldpipe then it could be pressure drop from the ic/piping
where did the dyno source their pressure reading, and where is your wg and gauge sourcing?
if you're sourcing at the hotpipe and they are at the coldpipe then it could be pressure drop from the ic/piping
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NeedCAforS13
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Re: (NeedCAforS13)
where do you have the gauge reading from, cause if it reading directly from the turbo your gauge could be accurate, but w/ pressure drop and *some* vaccuum, reading pressure at the intake/throttle body could be 5.5.
you want to hook your gauge up to the trottlebody to get the most accuarte boost reading your engine is seeing.
you want to hook your gauge up to the trottlebody to get the most accuarte boost reading your engine is seeing.
Re: (rico05)
I have a T28 with intake and turbo elbow back 3" exhaust. Also we hooked into the vaccum line that comes directly off the wastegate. I posted this same situation on another website and this is the reply i got:rico05 wrote:Wait, do you have the stock turbo, or a SR turbo?
Stock wastegate is 5.5psi, and the stock wastegate for a SR T25 is 7psi.
"That's normal. Gauge pressure is based on pressure over ambient. The dyno tap will read absolute pressure. We're in Calgary, our ambient pressure is on average 2psi lower than it would be at sea level."
Oh and for the record the numbers seem low because it was on a mustang dyno. The operator said i should add 9-10% on top of those numbers in order to have acurate rwhp. 137 x 1.1= 150.7 119 x 1.1=130.9
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knightrider
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Re: (Ca_Silvia)
most boost gauge's read "Gauge pressure".....and unless the DYNO is telling you your boost pressure is around 19psi.....then it is reading GAUGE pressure too.Ca_Silvia wrote: "That's normal. Gauge pressure is based on pressure over ambient. The dyno tap will read absolute pressure. We're in Calgary, our ambient pressure is on average 2psi lower than it would be at sea level."
Atmospheric pressure ( normal air pressure outside at SEA LEVEL ) is generally considered as 101.3kPa (1bar/14.7psi)
the Atmospheric pressure will get lower as you rise above sea level.......BUT the reading on your BOOST gauge will NOT change......as it measures Gauge pressure ( pressure above surrounding air pressure ).......so your boost gauge will still say 7psi.....but if you hooked up an "absolute pressure" gauge....it would read lower at higher levels
Re: (rico05)
Now why did you have to say something like that. Its hard for me to diagnose this engine, i had to replace the turbo as soon as i bought the car so i really have no idea what it "should" feel like. Also these numbers are without a tune, im hoping a tune should clear up some power issues.rico05 wrote:Wait, you have a T28 and a 3" exhaust and that is all you made? I would be concerned that something is amiss. My buddy made more with his stock KA on a DynoJet.
But this ****ing boost issue is driving me insane. Im going try and post my dyno results.
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knightrider
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well the car stock is rated at 170 hp at the flywheel, figure maybe 15% drivetrain lose. but the na CA is rated at sumthin like 130 hp so with your 5lbs your about right i guess, if you can fix your problem and get up to a respectable boost level and tune a little you might be on par. my CA made 110 hp without the turbo. later that day it did 190 hp at 12 or 15 lbs i forget. stock mani. elbow and downpipe with a ST.May NA Dual exhaust and a custom FMIC.
also does your car have a hard time idling, maybe you have a boost leak somewhere, try hooking the boost gauge up to a vacume line after the throttle body like the fuel presure regulator. you will get a more accurate reading of what the boost level is accually in the manifold, not right off the turbo. also your wastegate should be getting its signal from before the throttle body, but preferably after the intercooler so that you can account for the drop that the piping and intercooler provide.
also does your car have a hard time idling, maybe you have a boost leak somewhere, try hooking the boost gauge up to a vacume line after the throttle body like the fuel presure regulator. you will get a more accurate reading of what the boost level is accually in the manifold, not right off the turbo. also your wastegate should be getting its signal from before the throttle body, but preferably after the intercooler so that you can account for the drop that the piping and intercooler provide.
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sideways danny
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