Need some ideas on why I'm spooling slowly
 

Hey All,

I've done some troubleshooting on this and I'm not really having much luck sorting out my slow spool.

Details on the car:

Freshly rebuilt (by me) 2.0
Balance shaft eliminator
Timing was quadruple checked
ARP hardware/ACL bearings. Block and rods were cut with ARPs torqued.
Tomei baffle/scraper
Supertech inconel exhaust/nitrited intake valves
9.8 turbo
Walbro
Apexi drop in filter
Perrin MBC
*Slightly crushed 9 metal BOV

I'm reading that I should have 19psi by 3200rpm. I'm getting it closer to 4500 from what my logs show. I'd really like to nail this down.

Here's what I've checked:
2 boost leak tests, no leaks. Checked TB seals, injector seals (all new), intake manifold, all couplers, intercooler, etc.

Seemingly no exhaust leak before the turbo. When checking, the 2 large nuts on the extreme ends of the manifold were loose, but that didn't seem to make a difference, although I haven't logged it.

I tightened my wastegate actuator to the point that it started creeping. Didn't seem to make a difference.

Tightened the center clamp on the turbo. Didn't seem to make a difference, although it wasn't really that tight.

I'm running the crushed 9 recirc as a last minute bandaid. I broke the stock 8 plastic unit... twice. Found a good deal on this. Could the slight crushing be a problem?

Turbo seems to be in good shape. No play, spins freely.

Compression test came back great. Solid even number all 4 cylinders.

Tune is stock.

Any thoughts would be great!

What kind of exhaust do you have? You could have a restriction in the exhaust. I belive you can check this with a vacuum gauge.

Aside from what I listed, car is stock.

Catalytic convertor, or test pipe?

I want you to adjust the MBC to full soft (-). To do this, back the knob out all the way counterclockwise to its lowest possible boost setting. Take the car for a WOT run in 3rd or 4th gear. Note the peak boost level with the MBC set this way and then report back. Have fun!:)

Just to make sure, I'd also like to know whether or not you see any creep whatsoever with the MBC adjusted as suggested above, to its lowest setting.

Are you aware as to whether your VIII turbo is fitted with the 9.8cm, or the 10.5cm turbine housing?

You retightened these two nuts, I take it?

Cat or test pipe? Your cat could be clogged.

I listed in the original thread that it's a 9.8 turbo.

Yes, I tightened the nuts.

The cat is new. It was replaced by Mitsu under warranty.

Flapper in the exhaust not opening up? Could cause restriction. Stick a screw driver in there to see if it moves.

Will do!

I assume you mean wastegate flapper?

There is a flapper in the stock muffler.

https://www.evolutionm.net/forums/ev...k-exhaust.html

So I see! Didn't realize. I'll check it out. Thanks.

The hot side wheel could be damaged and missing or bent fins