Reducing turbo lag or get a smaller turbo?

Thread in 'Technical Questions' started by SkylineLvr, Jun 9, 2014.

  1. SkylineLvr

    SkylineLvr Member

    Joined:
    Oct 28, 2012
    Posts:
    287
    Likes Received:
    0
    I've got my S15 up for sale and have had some viewings. The downfall so far is the turbo lag. I currently have a PTE 5858SP which going off what I've read online falls between a GT3076R and a GT3582R in the Garrett family. The boost doesn't kick in till about 4k rpms. Everyone that's driven it has been dissapointed that it takes so long to kick in, but once it does kick in, it pulls hard.

    Would a good tuning/map job help in dropping down the lag, or would it be best to sell/trade this turbo for a smaller one that kicks in quicker? Anyone have any recommendations on a turbo? Thanks.
     
  2. Ruishy1

    Ruishy1 Active Member

    Joined:
    May 30, 2010
    Posts:
    3,739
    Likes Received:
    0
    Mapping will help a bit, but a smaller turbo would be better IMO.
     
  3. Stavros

    Stavros Active Member

    Joined:
    May 17, 2005
    Posts:
    26,133
    Likes Received:
    9
    Simple fact is, it's a 600bhp+ rated turbo.
    Turbos aren't magic.
    A turbo that big on I'm presuming a SR20 is going to spool about that rpm. In fact 4k is good for something single scroll that's supposedly good for over 600.
    If people expect a 600bhp+ turbo on a 2ltr without some flash twinscroll setup to spool sooner, they're dreaming.
    And if the engine isn't making big power, it's pointless having turbo that big.

    If people are expecting big performance under 4k, they need to be buying V8, not 2ltr turbo engines.
     
    #3 Stavros, Jun 9, 2014
    Last edited: Jun 9, 2014
  4. r3k1355

    r3k1355 Well-Known Member

    Joined:
    Nov 8, 2007
    Posts:
    3,465
    Likes Received:
    141
    This, people are probably unimpressed because the power doesn't compensate for the lag.
    If you're going to fit a massive turbo then the car better go like a sodding rocket, otherwise it's just a waste of time.
     
  5. SkylineLvr

    SkylineLvr Member

    Joined:
    Oct 28, 2012
    Posts:
    287
    Likes Received:
    0
    I agree with you completely. I didn't research as thoroughly as I should have. I'm now looking at downsizing, any recommendations on a good turbo?
     
  6. SkylineLvr

    SkylineLvr Member

    Joined:
    Oct 28, 2012
    Posts:
    287
    Likes Received:
    0
    Agreed.....now that we got the fact that the power to lag ratio isn't where it should be, what would you suggest be a good turbo?
     
  7. Stavros

    Stavros Active Member

    Joined:
    May 17, 2005
    Posts:
    26,133
    Likes Received:
    9
    What sort of power are you after?

    Unless you can't run much boost for some reason, the max bhp of the turbo shouldn't be far off the power you're after if you want the quickest spoolup.
     
  8. mint

    mint touch my fruit

    Joined:
    Jul 4, 2007
    Posts:
    7,790
    Likes Received:
    25
    Not just stick in a standard T28 to sell it?
     
  9. Stavros

    Stavros Active Member

    Joined:
    May 17, 2005
    Posts:
    26,133
    Likes Received:
    9
    Looking at your for sale ad, there's no mention of injectors etc, so are they all stock?

    If so, the stock turbo is all you ever needed, as you haven't got the fuel for much more.

    Then at least you can sell that big turbo setup for good money maybe, as TBH it sounds quick spooling for a 600bhp+ turbo lol.
     
  10. SkylineLvr

    SkylineLvr Member

    Joined:
    Oct 28, 2012
    Posts:
    287
    Likes Received:
    0
    The previous owner didn't know what injectors it has. I took one out and the part number on it brings up NISMO 740s online. I'm not positive they are 740s, but they do have a red top and look like 740s.
     

Share This Page