FE3 Turbo build. Need your help...
 

Hi!


Excuse my bad english as first.

I need your help...

I have build a FE3 Turbo this year.

But I have problems boosting more than 7 psi (update 9 psi).

Specs:

- FE3 Mazda block
- FWD FE3 Kia head with some port-cleanup, VR6 springs
- FWD FE3 Kia cams
- Woessner turbopistons, 87mm 8,2:1
- Mazda FE3 rods, shootpened and polished
- balanced crankshaft and flywheel
- DIY headstuds
- oem headgasket
- slightly ported inlet manifold with 65mm tb, VICS closed
- 1200cc FINjectors (siemens deka)
- Bosch 044 pump with intank-kit
- Garrett GT3582R T3 .63 AR
- nearly equal lenght exhaust manifold. very short runners. (no space)
- 38mm external wastegate with 20 psi spring
- 2,5 inch intercooler piping
- 3 inch downpipe and exhaust
- 2,5 inch muffler
- ms2 standalone
- forge 32mm bov
- usual ebay intercooler


Since last week, im able to drive and tune it. So far so good. Engine runs great off-boost with good torque.
AFR´s and ignition timing are conservative, read safe. Not to rich and not to lean.

Turbo starts to build positive boost in 3th gear from 2800 on, climping slowly but steady to 7 psi at 4900.
More revs doesn´t build more boost. It´s like the wastegate controls it.
No ebc or mbc, wastegate is connected directly to the turbo outlet.

So:

- 3400 2 psi
- 3900 4 psi
- 4300 6 psi
- 4900 7 psi to 6000 without changes in boost level

There are no boost leaks. I´ve checked that twice.
I´ve checked compression and cam timing, all good.
The car is fast even at such low boost numbers.
Because the turbo starts so early, I think I can ignore exhaust back pressure who opens the wastegate and so forth.
Maybe the stock Kia cams are not up for the task. By contrast, my last nearly stock FE3 with a GT2871R revs nicely to 7000 without a lot off torque lose. Hmm...


I can post a datalog if needed.



Update: (yesterday)

I´ve worked on the car tonight, doubled the wastegate spring. Small diameter 20 psi and one big diameter spring 14 psi. That is a lot of preload.

Psi goes up a little, from 7 psi to 9 psi at the same revs.
Next I´ve disconnected the buttom wastegate-line, without changes in boostlevel.

Holy moly! Even at 9 psi its powerfull. It´s the first time I can hear the turbo whistle... thrilling!

Tommorrow I´ll swap that silent 2,5 inch muffler to a straight pipe. Let´s see. So no mufflers at all...


Update: (today)

Swaping the muffler to a straight pipe doesn´t changed much.
Played with the timing map and ve table. Nothing.

It holds the 9 psi as straight as an arrow from 5000 up. No surge, no boost creep.

Any ideas?


Many thanks!

Stefan-Joerg

Either your wg is stuck open or doesn't close, or you have a giant leak, or your turbo is toast

FE3 on a 35R sounds like a serious setup. got any pictures?

Have you tried a boost controller on it? I'm not sure what the wastegate springs really signify... your number suggest you should be hitting 34psi on wastegate alone, but i'm guessing that's not anywhere accurate.

You may just not even be waking up that turbo yet.

The spring ratings are usually pretty accurate.

He's got a giant leak somewhere or his turbo is kaput.

Thank you for your answer, 18psi!

I´ve tested two different wastegates. One old turbosmart and a new tial knock off. There are no signs of blowby. And both wastegates producing the same results.

Turbo is used but with only 3000km (2000miles) on it.

Best regards,

Stefan-Joerg

https://www.miataturbo.net/attachmen...ine=1407336873

holy crap you have that setup in one of those little things? :laugh: that's AWESOME. I bet its going to spin all the way into 5th. my buddy had a BP-turbo festiva and hurt a lot of feelings around here with it. Awesome sleeper

If you ruled out the wastegate and there's no exhaust leaks, I'd start checking for boost leaks. Have you done a boost leak test? If its not a leak or the wastegate, then something is wrong with the turbo. I think even with a 2.5" exhaust you should see more than 9psi out of that thing.

Hi concealer404! (from mx6.com?) :-)

No boost controller connected. But I can give it a try.

Yes, I have done a boostleak-check. No leaks.

The turbo spins free and the blades are fine, without scratch-marks in the housing. It´s like new and not a chinese copy.

It spins the tires in 3th gear with 9 psi. So next stage is 14 psi for 4th gear tire spin madness.. :-)

and both the turbine and compressor housings are bolted down properly and sealed properly right? its not loose from clocking or assembly?

Ahhh... i didn't get the memo that we were talking about an external wastegate in this case.



In that case... take the wastegate back off and make sure you aren't missing the fire ring. ;)


Also: Hi! :D

Yes, i´ve found a valve seat on my workbench, must be some part of the wastegate. :rofl: And that´s true...
To my surprise, even with such a gap, doesn´t changed much in boost level.
Only boost threshold goes just about 500 rpms down.
Nobody´s perfect.

[IMG]https://www.miataturbo.net/attachmen...ine=1407340011[/IMG]

I will check that tonight.

so the fire ring wasn't in place? there's your problem right there.

you better take 30psi worth of springs out once you replace that ring.

or you're gonna be in for a couple of seconds of SERIOUS FUN followed by lots of tears :D

Yes and no :-)

It´s in it´s place since this morning.

What does your wideband say in boost? Going real lean or going stupid rich can really hamper the amount of boost you can make. Having too much back pressure wont limit boost like that, it normally would make more boost but less flow and more heat so less fast. If the waste gate is sealing, there arent any pre-turbo exhaust leaks, there arent any boost leaks, then either the turbo is toast or you tune is completely fucked.

Off-boost 13.5, merging to 13.0-12.5 from 100kpa to boost level. In boost 12.2 to 11.5 (9 - 10 psi). Ignition 24 degrees btdc at 4000 - 5000 for 120 to 150 kpa range.

that is some manly timing on pump gas :)

8.2:1 pistons.

8.2:1 compression. F-series motors (barring FS-DE) are even bigger timing whores than BPs.

Learn something new every day :party: