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-   -   Crappy spool with sr20 t25? (https://www.miataturbo.net/diy-turbo-discussion-14/crappy-spool-sr20-t25-98222/)

spencerh22 10-03-2018 10:19 AM


Originally Posted by muthagoose (Post 1504605)
Long shot, but did you plug the stock wastegate mount holes? They pass fully though to the compressor.

Yup, put bolts in them with thread sealant. Unless the ones on the back pass through as well.

spencerh22 10-03-2018 10:42 AM


Originally Posted by WigglingWaffles (Post 1504597)
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

Plumbed back into intake yes. Hmm i’ve never heard of that.

sixshooter 10-03-2018 11:34 AM

Block off BOV opening completely and see if it makes a difference. You said BOV was soft.

andyfloyd 10-03-2018 04:39 PM

I can attest to a T3 outspooling a T25. I had a .48/T3 60 trim on my 1.6L and it was an absolute spool monster and spooled faster than a GT2560R which is going to spool about the same as a journal T25 since they have the same hotside parts.

spencerh22 10-03-2018 07:58 PM

Well, fixed my blow off valve that was open at idle, nothing changed. Tomorrow i will try fabbing a new downpipe and check out the wastegate and see what’s goin on in there. Really disappointed with this turbo, anyone else have an sr t25 and have spool data?

borka 10-03-2018 07:59 PM

At what rpm are you hitting 10psi in 4th gear?

HmoobDude 10-03-2018 08:08 PM


Originally Posted by spencerh22 (Post 1504749)
Well, fixed my blow off valve that was open at idle, nothing changed. Tomorrow i will try fabbing a new downpipe and check out the wastegate and see what’s goin on in there. Really disappointed with this turbo, anyone else have an sr t25 and have spool data?

Read the sticky at the top of this section.

irollgen4s 10-03-2018 09:30 PM

I have a .86 hotside t25 on my stock 1.6 and in 4th i hit 10PSI at around 4300rpm. My SR t25 that i ran previously was equally laggy feeling for some reason with a lot less punch this .86 housing hits hard in comparison to the sr t25 but still spools around the same RPM. Doesn't make any sense to me but i like it. Though the turbo i'm running is made by a company out in vegas and is available on the classic fleabay. It is aimed at SR's and can make way more than what my 1.6 can handle so i figured it would be pretty laggy.

yossi126 10-04-2018 01:48 AM

My sr20 t25 spools to 13 psi @ 2900 rpm.
Spool is instant and there's no lag. It lacks in punch though. I can only compare by feel to a friend's gt2560r that it takes half a second to feel it spin but then it takes off like a rocket ship.

spencerh22 10-04-2018 05:05 AM


Originally Posted by yossi126 (Post 1504820)
My sr20 t25 spools to 13 psi @ 2900 rpm.
Spool is instant and there's no lag. It lacks in punch though. I can only compare by feel to a friend's gt2560r that it takes half a second to feel it spin but then it takes off like a rocket ship.

What’s your setup? That’s the spool i’m after..

18psi 10-04-2018 10:51 AM

let's see some pics of your bay and this custom log mani you mentioned

90civichhb 10-04-2018 12:14 PM

Are you using an EBC? Do you have any logs? I have a 1.6 with a t25 on 14ish lbs and see that target before 3500rpm with proper EBC settings. Kraken manifold and 2.5” exhaust.

spencerh22 10-04-2018 01:25 PM

No ebc yet, going to order one soon. Here are requested pics
https://cimg5.ibsrv.net/gimg/www.mia...4deb8cee8.jpeg
https://cimg0.ibsrv.net/gimg/www.mia...791d993a0.jpegCustom mani

90civichhb 10-04-2018 01:36 PM

is your valve cover PCV port just open to atmosphere on both side? That seems like a fire just waiting to happen to me.

You’re probably getting some wastegate flex with that mounting solution. My car feels very lazy on just wastegate spring. It’s only like 6psi and I don’t see that until 4K rpm or so. Get some sort of WG control on the car. Also that crunched downpipe isn’t doing you any favors.

The 1.6 has a great oil feed on the block you can use and right next to it is a water feed, which looks like you choose not to even water cool the turbo. Kinda questionable but I’ve seen people do that after cracking a feed line on track.

spencerh22 10-04-2018 01:38 PM


Originally Posted by 90civichhb (Post 1504935)
is your valve cover PCV port just open to atmosphere on both side?

yep, haven’t had issues with blowby.

90civichhb 10-04-2018 01:44 PM

Sorry, on mobile. I edited my original post with more input.

sixshooter 10-04-2018 01:46 PM

I see what's going on. Turbo is actually in self-preservation mode. It is staying out of boost to prevent you from dying from brake reservoir failure.

18psi 10-04-2018 01:48 PM

you're not using boost control of any sort and tee-ing off the compressor outlet.........

.,.............and wondering why your spool sucks? lol

90civichhb 10-04-2018 01:51 PM

You probably need to read some more build threads on here. You’ve got the parts but you’re doing some strange things that look kinda like willful ignorance.

yossi126 10-04-2018 02:03 PM


Originally Posted by spencerh22 (Post 1504827)

What’s your setup? That’s the spool i’m after..

Basically an fm kit.
Looks to me that your wastegate rod is too long. That can hurt spool.


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