Help with a flow restriction

Discussion in 'Modifications & DIY how-to' started by WRboXer, Jul 6, 2012.

  1. WRboXer

    WRboXer Active Member

    I got my BNR 18g LGT tuned at topspeed not to long ago, the car in my mind made sub par numbers(300whp, 330wtq-21psi 93oct). Doug was getting a flat lined maf reading without maxing the maf, leading us to believe there was a flow restriction. Other 18g's ive seen tuned including another BNR put down around ~330whp on TS's dyno, but i dont know if those were outliers and perhaps im just expecting to much from my setup.

    My question is, what would be causing that big of a flow restriction in my setup below?

    100k mile LGT
    Exhuast
    -oem header
    -catless uppipe
    -invidia catted downpipe
    -perrin midpipe
    -prodrive catback

    Fuel
    -dw 65c
    -deats 850cc injectors

    Intake/Turbo/IC
    -full oem intake tract with K&N panel filter
    -BNR 18g
    -Perrin TMIC

    -Cobb AP2

    My 16psi and 21psi pump gas maps below.
    [​IMG]
     
    Last edited: Jul 6, 2012
  2. CelticPride

    CelticPride Banned

    -full oem intake tract


    You haven't upgraded the accordian pipe or the turbo inlet? That's a restriction on the WRX and is usually upgraded when bigger turbo is put on.
     
  3. WRboXer

    WRboXer Active Member

    I was told by importimage that an inlet would provide no gains and the oem intake was the bottle neck, i keep getting contradictary info.
     
  4. CelticPride

    CelticPride Banned

    Josh has said similar things to me before....I would not listen to a sales shop vs a tuner. Did you ask Doug what he thought?

    The OEM airbox is NOT a restriction until 400hp or so. But the pipes after it can be.


    Also the catted downpipe will lose hp too but 30 hp is a bit much imo.
     
  5. WRboXer

    WRboXer Active Member

    Yep, doug was saying the car may pick up 30whp with an inlet, but didnt mention the intake box. But i would be VERY surprised if the inlet was creating 30whp worth of restriction.

    I just want to make sure all my ducks are in row before i go back again, as this will most likely be the cars last tuning session for pretty much the life of the car.

    Yeah whatever the restriction is def seems to be intake related.

    I may go catless with an aftermarket header(just thoughts though).
     
  6. slowwrx

    slowwrx Supporting Member

    The intake box itself is fine, you need to change out the turbo inlet for sure. I would be suprised it it was 30hp but I wouldn't be if it was 15hp.
     
  7. CelticPride

    CelticPride Banned

    On my 2.0l 18g headers gained little overall HP but gained tons of midrange. Search coolrex old posts if you want comparisons. If I can find the chart I will post it.
     
  8. CelticPride

    CelticPride Banned

    But inlet and catless downpipe may come close on a cooler day...these temps don't help.
     
    Last edited: Jul 6, 2012
  9. slowwrx

    slowwrx Supporting Member


    Very true, I didn't see the catted downpipe.

    I would say between those two is your hp.
     
  10. WRboXer

    WRboXer Active Member

    I still miss my 2.0 VF-39 car, that thing ripped.

    Below is my 05 sti with tbe and tune, 02 WRX with vf-39 and pretty much every bolt on, and 05 LGT with bnr 18g...all tuned to 21psi on pump.

    [​IMG]
     
  11. CelticPride

    CelticPride Banned

    Here's my old comparison. td05h 18g on meth diet on a bone stock 2.0L engine with all bolt on mods and EWG.

    Stock headers vs Maddad large primary ELH. Both tunes are identical at 26 psi and the ONLY difference is the headers. Everything else is the same.

    [​IMG]
     
  12. WRboXer

    WRboXer Active Member

    Thats pretty nifty, and alot of freakin boost on a stock 2.0, how long did that last?
     
  13. CelticPride

    CelticPride Banned

    That tune was done at 105k miles. Was still running with no issues at 170K miles. Car was at 24 psi since 10k miles. EJ205 FTW. I never should have pulled that engine for the EJ257.

    Not a freak either. My coworker's bugeye ran the same boost on a EvoIII 16g with no issues. I think Techlord ran that boost too.
     
  14. slowwrx

    slowwrx Supporting Member

    Properly tuned a stock 2.0 is pretty tough, we beat on my brothers pretty hard. Even tried to make a pass at 400whp. Clutch died, then tranny, then engine.
     
  15. Berzerklo

    Berzerklo Active Member

    Slightly off topic, but why did you go with the BNR 18G, OP? I am still a ways from swapping turbos in my Legacy, but I had been leaning towards a VF-52 when that day comes...
     
  16. b reel

    b reel Active Member

    flow in = flow out

    what filter do you have in the box?

    burnt exhaust valves don't help either, done a leak-down?
     
    Last edited: Jul 6, 2012
  17. CelticPride

    CelticPride Banned

    EDIT....read it up on google...found it and yup pretty much a borked exhaust valve.
     
    Last edited: Jul 6, 2012
  18. WRboXer

    WRboXer Active Member

    Bc an 18g flows much more then a vf52, and the mitsubishi td05 chra should be more effecient, more reliable, and rebuildable which the IHI VF is not. Pretty easy choice in my mind, if i were you i would go BNR 16g. Plus BNR is somewhat local being in birmingham, al.
    k&n filter, no leak down because every other performance metric has been spot on. Still gets ~24mpg with mixed city driving and burns 1/4 quart in 3k miles. Unless a burnt exhaust valve is that undetectable.
     
  19. WRboXer

    WRboXer Active Member

    Matt whats the typical weak link on the 205's? I know the 255's/257's the ringland is the number one issue, but what about the smaller pistoned 205's?

    For the record, if i had my choice V7 EJ207 would be my engine of choice.
     
  20. slowwrx

    slowwrx Supporting Member

    They break rod bolts at that power level. They sometimes break ringlands as well.

    The 205 case itself is actually pretty strong and I wouldn't hesitate to build them up to about 400-450whp.

    The newest EJ205 crank has the same oiling at the EJ207 cranks so its great for high rpm builds.
     
  21. wagunz_pwn

    wagunz_pwn Active Member

    Did you forget the K&N sticker? It might only get you 5hp...but it's a start.
     

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