Whats the most boost without changing internals

  1. Frequent Poster Joined: Jul 2008 Posts: 524
    #1
    whats the most boost u can get without changing the engine internals any ideas
  2. L-plater Joined: Jun 2008 Ipswich Posts: 80 106 WITH VTR engine! so kinda saxo :D
    #2
    dont do it basically lol
    gains wont be worth it at the low boost needed to safely run it, and if it goes wrong, very expensive, i suppose at the minimum you could get a thicker head gasket, that would lower the comp a bit, but i wouldn't risk it personally
  3. Established Member Joined: Dec 2007 Southampton Posts: 2278
    #3
    depends on the spec, however i would say 180 ish is quite safe on a stock VTS with a simple decomp plate
  4. Frequent Poster Joined: Jul 2008 Posts: 524
    #4
    the spec is a mk2 VTR
  5. Established Member Joined: Dec 2007 Southampton Posts: 2278
    #5
    Very exstensive lol

    I was refering too the compression ratio that you chose to run more than anything.

    On a VTR i guess your power figure drops too around 150 "reliably"
  6. L-plater Joined: Jun 2008 Ipswich Posts: 80 106 WITH VTR engine! so kinda saxo :D
    #6
    I still wouldnt go near that figure, if you want to turbo it, get it done right, with mapping and low comp pistons etc.
    will be worth it in the long run as you could have 200+hp without the fear of any bad knock or fuelling issues etc.
  7. Frequent Poster Joined: Nov 2003 Tayside Posts: 893 S/c VT!?
    #7
    Not entirely the boost level that will determine how safe it is.

    Run 0.5bar with 50 degree inlet temps, or run 1 bar with 20 degree inlet temps and see which one lasts longest.

    Also - the better the engine 'eats' the boost, you'll get the same power for less boost (or more power for same boost).

    On standard internals the heat generated will eventually crack the pistons, just a matter of how long it takes to do so. Although you should be able to run quite a substaintial amount of boost on standard internals, provided you do it correctly (very good intercooler, standalone and good mapping).
  8. Frequent Poster Joined: Jul 2008 Posts: 524
    #8
    ok thanks very helpful im just getting an idea of what to do later on when the money doesnt become a problem if that ever happens,

    anyway if im running i high spec saxo like this as above say if i turboed it or the stage before that would it be safe to run on roads ect or does that just depend on my driving which is very sensible
  9. L-plater Joined: Jun 2008 Ipswich Posts: 80 106 WITH VTR engine! so kinda saxo :D
    #9
    as everybody will tell you ALWAYS upgrade brakes and suspension with upgraded power, then you should be fine, unless your a bellend in which case you'll torque steer into a tree with power
  10. Infrequent Poster Joined: Oct 2006 Posts: 187
    #10
    I know one running 1 bar of boost with IHI turbo charger from impreza uprated injectorcs, cooler, remaped. It's everyday car so it's reliable.
  11. L-plater Joined: Aug 2005 Posts: 46
    #11
    It always makes me chuckle when people talk about standard "internals" when running boost. The only thing you need to change is the pistons, just do it! lol
  12. Infrequent Poster Joined: Jul 2008 Sheffield Posts: 233 Posi Blue VTR 2000 reg.
    #12
    im running tdo4, shoule be coming together pretty soon, and im going to run 0.5 bar first then tweek it up until it goes 'pop' then forge it!
  13. Frequent Poster Joined: Nov 2003 Tayside Posts: 893 S/c VT!?
    #13
    Quote:
    Originally Posted by notts106gti View Post
    It always makes me chuckle when people talk about standard "internals" when running boost. The only thing you need to change is the pistons, just do it! lol
    Unless of course you're running a VTR engine - in which case you'll need to change the rods as well, either to VTS ones or forged items. As the majority of forged pistons are a different fitment to the rods than is standard on a VTR.
  14. Established Member Joined: Jan 2008 Posts: 1802
    #14
    Quote:
    Originally Posted by notts106gti View Post
    It always makes me chuckle when people talk about standard "internals" when running boost. The only thing you need to change is the pistons, just do it! lol

    Whilst that is true, it's also wise to re-bore 0.5mm, and fitting rods becomes no probs, and whilst you're there why not a set of bearings, oh and a new oil pump since it's got more work to do... I think that's the thought process most people go through - "while I'm in there" or "I'm only going to do this once".

    I've learnt a very important lesson during my tuning years - you can pay once now, or TWICE later...

    Get it right first time!
    Andy
  15. Infrequent Poster Joined: Jul 2008 Sheffield Posts: 233 Posi Blue VTR 2000 reg.
    #15
    Quote:
    Originally Posted by luthor1 View Post
    Whilst that is true, it's also wise to re-bore 0.5mm, and fitting rods becomes no probs, and whilst you're there why not a set of bearings, oh and a new oil pump since it's got more work to do... I think that's the thought process most people go through - "while I'm in there" or "I'm only going to do this once". I've learnt a very important lesson during my tuning years - you can pay once now, or TWICE later... Get it right first time! Andy
    What oil pump should i use then if i have to change it?
  16. Established Member Joined: Jan 2008 Posts: 1802
    #16
    There *may* be uprated items available (ask KAM or GMC?), I would just point out that a new one would be favourable over a xx,xxx miles old one that's all

    Andy
  17. Saxperience Post Whore Joined: Jan 2007 Shropshire Posts: 9994 Moonstone Blue 106 GTi
    #17
    ran 1 bar through my old 1.1 before I tried 20psi lol

    will last for a long time if mapping is done right, know of a few 16v that are running standard internarls for along time now with no problems, but then again the mapping has been spot on
  18. Infrequent Poster Joined: Jul 2008 Sheffield Posts: 233 Posi Blue VTR 2000 reg.
    #18
    u rekon i will be able to run a bar on my vtr?
  19. L-plater Joined: Sep 2008 Posts: 30
    #19
    Lot's of random replies in here.

    Boost doesn't break engines, power/torque/rpm's do.

    Most of it comes down to the mapping, 7psi on a small turbo isn't the same as 7psi on a large turbo.
  20. Frequent Poster Joined: Nov 2003 Tayside Posts: 893 S/c VT!?
    #20
    Quote:
    7psi on a small turbo isn't the same as 7psi on a large turbo
    Think you'd be best to clarify what you mean by that - as 7psi = 7psi no matter how you look at it.

    I'm guessing what you mean is that with a smaller turbo the boost will build in a different way to the large turbo - resulting in the 7psi coming in at a different point in the rev range. If it comes in low down rpm range then you get a high torque figure, if it comes in higher up you get a high bhp figure.
  21. Frequent Poster Joined: Nov 2003 Tayside Posts: 893 S/c VT!?
    #21
    Quote:
    7psi on a small turbo isn't the same as 7psi on a large turbo
    Think you'd be best to clarify what you mean by that - as 7psi = 7psi no matter how you look at it.

    I'm guessing what you mean is that with a smaller turbo the boost will build in a different way to the large turbo - resulting in the 7psi coming in at a different point in the rev range. If it comes in low down rpm range then you get a high torque figure, if it comes in higher up you get a high bhp figure.
  22. Infrequent Poster Joined: Jul 2008 Sheffield Posts: 233 Posi Blue VTR 2000 reg.
    #22
    Quote:
    Originally Posted by gd16 View Post
    Think you'd be best to clarify what you mean by that - as 7psi = 7psi no matter how you look at it. I'm guessing what you mean is that with a smaller turbo the boost will build in a different way to the large turbo - resulting in the 7psi coming in at a different point in the rev range. If it comes in low down rpm range then you get a high torque figure, if it comes in higher up you get a high bhp figure.
    think he means if u run a bar on a gt17 and a bar on a gt28 thers going to be alot of difference
  23. L-plater Joined: Sep 2008 Posts: 30
    #23
    Quote:
    Originally Posted by gd16 View Post
    Think you'd be best to clarify what you mean by that - as 7psi = 7psi no matter how you look at it.

    I'm guessing what you mean is that with a smaller turbo the boost will build in a different way to the large turbo - resulting in the 7psi coming in at a different point in the rev range. If it comes in low down rpm range then you get a high torque figure, if it comes in higher up you get a high bhp figure.
    Not when it comes to turbo's.

    7psi on a small turbo isn't the same as 7psi on a large turbo. The boost pressure is of cause the same, but boost doesn't make bhp/torque/power air does, more air flow equals more power (providing you have the fueling etc).
  24. L-plater Joined: Jun 2008 Ipswich Posts: 80 106 WITH VTR engine! so kinda saxo :D
    #24
    so how much would it cost if i bought a turbo and simply forged the pistons and rods?? doing all labour myself?
  25. Saxperience Post Whore Joined: Aug 2004 Kunt & Sorrey Posts: 5763 Rep mobiles & Joes ma
    #25
    if done well a bar on standard internals would be ok, if looking for ultimate reliability 7-10psi is a better compromise.
  26. Frequent Poster Joined: Nov 2003 Tayside Posts: 893 S/c VT!?
    #26
    Quote:
    so how much would it cost if i bought a turbo and simply forged the pistons and rods?? doing all labour myself?
    Far too ambiguous a question.

    Depends what intercooler and oil cooler you bought, what kind of manifold / downpipe you bought, and how you want to control the fuelling. Then all the little costs that add up too.


    Forged pistons and rods = £1100+
    Should be getting mine this week
  27. L-plater Joined: Jun 2008 Ipswich Posts: 80 106 WITH VTR engine! so kinda saxo :D
    #27
    i know i was mainly looking for the cheapest price i could get it
    but if its worth doing its worth doing right so I think Ill wait until i have the money to do it all properly and get the most from it anyway, cheers for the advice even though this wasnt my thread
  28. Frequent Poster Joined: May 2008 Cumbria Posts: 526 2000 VTS
    #28
    Quote:
    Originally Posted by luthor1 View Post

    I've learnt a very important lesson during my tuning years - you can pay once now, or TWICE later...

    Get it right first time!
    Andy

    Ahh, the old saying a poor man pays twice. Tis right with everying in life though!