How crucial is a BOV/BPV for turbo applications?

Started by AC, February 13, 2010, 15:07

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AC

Having ordered and received my charge cooler kit I have been offering up the barrel to gauge what changes I need to make to the piping from compressor outlet to TB.  I purposely choose the 4x6 barrel as pipe run is somewhat limited (on the plus side it will be something like 70-80cm run from comp outlet to TB with CC in middle  s:) :) s:)  ).  However without major re-working (basically cutting down the SS Apexi comp outlet pipe, and that's still no guarentee to work) I won't be able to re-fit a BOV/BPV  s:? :? s:?  .

I have read on here a few things that make me wonder whether to leave it out; 1. the TTET doesn't use one and boosts up to 10psi for some people.  2. there is a school of thought that a BOV/BPV isn't a necessity below 1 bar boost and or with non ceramic compressor blades (mine's steel, or the like).

I'm running up to 10psi now (making 230hp), when I get re-mapped for the 440cc's and CC I was planning on leaving the boost the same, well for certain less than 1 bar, as I think I might see 250hp with just better fueling and CC.

Have any turbo peeps (other than TTET owners) ran without BOV/BPV permanantly?  If so, any detriment/issues?

I do realise the reason for the BOV; prevent compressor stall and therefore damage.  But I was also thinking that the CC will act as a pressure modifier and that could maybe also offset being BOV-less?


[size=85]The famous Walter Rohrl once said "Stay away from rear-wheel-drive cars unless.......", I had to agree on one particular occasion, but we did live happily ever after (apart from the trousers, they were a write off).

markiii

personally I found that uwith less than 1 bar and a metal bladed turbo you are actually better off without one
Gallardo Spyder<br />Ex Midnight Blue 911 T4S<br />EX VXR220<br />Ex Custom Turbo 2001 Sahara Sun MR2 Roadster 269bp, 240lbft<br /><br />MR2ROC Committee 2002 - 2009<br /><br />

AC

I remember reading your post Mark of when you were playing with the idea and you did comment that spool up/response was better.

Did you leave you Hass BOV-less then after that?


[size=85]The famous Walter Rohrl once said "Stay away from rear-wheel-drive cars unless.......", I had to agree on one particular occasion, but we did live happily ever after (apart from the trousers, they were a write off).

spit

I believe he did.

TTET and PE don't have one as standard and don't appear to suffer as a result. I've tried with and without - haven't noticed the difference that Mark has but I'd go with his judgement as I've never truly hammered mine.
1999 MR-S with added C2 POWΣR

Humbled recipient of the Perry Byrnes memorial trophy (2007 & 2011)

VVT-i

I'm along the same line as Spit.. I've got the P.E kit (234bhp, I/C) I had a BOV but it developed a fault and I now run without one, I haven't noticed any difference in performance, no whooooosh! sound now tho. Like Spit, I don't hammer the car very often.
2005 MR2 Roadster  (Black)
P.E. Turbo and other stuff that gives 234BHP  \";)\"

Quote from: \"Wabbitkilla\"Mine is a bit stiff when cold, but once it\'s warmed up it slips in nicely.

AC

I had changed from a BOV to a BPV (re-circ) mainly to see what improvement to spool it would give, it was marginal actually but that might just have been my set up.

Valve-less looks the answer then, without hacking the original Apexi pipework, unless I can get my hands on a 45 degree 57 - 51mm silicone reducing elbow with 25mm dump valve T outlet???  s:crazyeyes: :crazyeyes: s:crazyeyes:  (I have checked, it was hard enough just finding 57mm silicone (2.25 inch)).


[size=85]The famous Walter Rohrl once said "Stay away from rear-wheel-drive cars unless.......", I had to agree on one particular occasion, but we did live happily ever after (apart from the trousers, they were a write off).

markiii

its a trade off, the time between refilling the pipes V bringing the turbo back up to speed

a recirc valve should give you the best of all worlds, but with the the Hass I found it best with none at all. I ran it that way for most of its life

I think Simon is still running my old kit that way?
Gallardo Spyder<br />Ex Midnight Blue 911 T4S<br />EX VXR220<br />Ex Custom Turbo 2001 Sahara Sun MR2 Roadster 269bp, 240lbft<br /><br />MR2ROC Committee 2002 - 2009<br /><br />

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