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Crappy spool with sr20 t25?

 
Old 10-02-2018, 08:27 PM
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Default Crappy spool with sr20 t25?

Whats goin on guys, i recently switched from my ebay t3 manifold with the braineack 50 trim, to a custom log mani with an sr20 t25. Just got the setup finished and my spool is garbage. 5 psi by 3200 in 5th, worse in 4th. The whole reason i changed my setup around was for better spool, but my spool is horrendous. Iíve checked for boost leaks, tightened the wastegate arm(wg moves back and forth freely and doesnít open until 10psi of compressed shop-air), and for pre turbo leaks. Everything seems fine, what gives? I also have a tial bov that after the turbo install, sounds a little different and quieter. Itís open at idle because the spring is too light, but it shouldnít be leaking under boost, and it didnít in the boost leak test. What the hells goin on here?
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Old 10-02-2018, 08:52 PM
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Vac/ boost source line?
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Old 10-02-2018, 08:56 PM
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Originally Posted by thirdgen View Post
Vac/ boost source line?
Wg is from port on turbo, boost gauge from port on manifold. Blow off valve from pcv port on manifold.
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Old 10-02-2018, 09:39 PM
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1.6L?
And welded el logs dont spool all that good
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Old 10-02-2018, 09:43 PM
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Yeah 1.6, i know they donít spool too good. But this bad? I was running a t3 before with the ebay log and it spooled better..
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Old 10-02-2018, 11:22 PM
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Bump?
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Old 10-03-2018, 07:38 AM
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What's the turbine housing a/r on the t25 and the old t3?

Some t3's spool earlier than some t25's for various reasons. Not all t3's are the same. There's a huge variation in the series.
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Old 10-03-2018, 08:17 AM
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Originally Posted by spencerh22 View Post
Yeah 1.6, i know they donít spool too good. But this bad? I was running a t3 before with the ebay log and it spooled better..
This is what you should roughly be able to do. I have always thought the SR20 t25 on the 1.6l responded horribly for whatever reason.
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Old 10-03-2018, 09:10 AM
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Originally Posted by sixshooter View Post
What's the turbine housing a/r on the t25 and the old t3?

Some t3's spool earlier than some t25's for various reasons. Not all t3's are the same. There's a huge variation in the series.
.48 on the ol t3, .64 on the t25 i believe. It just feels off. Iíve heard of people gettin almost instant spool with the t25s. But my transient response is garbage too..
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Old 10-03-2018, 09:12 AM
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The only thing i can think of that might be causing it, is that i had to clearance my downpipe quite a bit in order to clear the shelf with my vband adapter. I had to hammer it at the elbow, could this really be a bottle neck? I ordered a slimmer adapter and am going to try and see if a pie cut downpipe gives me a little better spool.
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Old 10-03-2018, 09:27 AM
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A .48 will make a small t3 spool pretty damn quick. Exhaust wheel and compressor wheel size and trim can make a difference in spool also but I bet most of it in this case is in the turbine housing a/r. You can look for a smaller one for the t25 if matters that much.
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Old 10-03-2018, 09:30 AM
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Originally Posted by sixshooter View Post
A .48 will make a small t3 spool pretty damn quick. Exhaust wheel and compressor wheel size and trim can make a difference in spool also but I bet most of it in this case is in the turbine housing a/r. You can look for a smaller one for the t25 if matters that much.
I agree, but a smaller turbine AND compressor wheel with a .64 ar which is equal to the 48 on the t3 and spool is this much worse? Something is off here.
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Old 10-03-2018, 09:33 AM
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I have a T25 on my 1.6 and it hits my target boost around 3500
what's your exhaust setup?
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Old 10-03-2018, 09:52 AM
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Originally Posted by WigglingWaffles View Post
I have a T25 on my 1.6 and it hits my target boost around 3500
what's your exhaust setup?
2.5 downpipe all the way back, clearanced to probably around 1.75-2Ē at the turbo exit. Whatís your target boost?
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Old 10-03-2018, 09:55 AM
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11psi, but I have 3" exhaust.
is your idle valve plumbed into the intake tract? I've heard of those bypassing boost without a check valve
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Old 10-03-2018, 10:03 AM
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I didn't see it mentioned, but could something perhaps be wrong with the turbo itself? Was the "new" turbo used?
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Old 10-03-2018, 10:08 AM
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I should have a T25g turbo for sale here shortly, Includes an unused 360 degree dynamic seal kit.
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Old 10-03-2018, 10:10 AM
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Originally Posted by HmoobDude View Post
I didn't see it mentioned, but could something perhaps be wrong with the turbo itself? Was the "new" turbo used?
Yeah, it was, but i rebuilt it. Everything seems fine with the turbo.
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Old 10-03-2018, 10:13 AM
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Journal bearing sr20 t25 turbos are not really spool monsters. I've had one on my 1.8L nb2 miata and was not impressed with the spool, the gt2560r I later installed spooled better. The t25 was not horrible, but not great, considering the small size. This was on a begi cast manifold and 2.5" dp to 3" exhaust.

a 1.6l with weld els log and smashed Downpipe is not helping it spool all that great...

Still it should come alive around 3500rpm or so
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Old 10-03-2018, 10:17 AM
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Originally Posted by spencerh22 View Post

Yeah, it was, but i rebuilt it. Everything seems fine with the turbo.
Long shot, but did you plug the stock wastegate mount holes? They pass fully though to the compressor.
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