0R10N Posted September 5, 2011 Share Posted September 5, 2011 Are turbos too newschool for oldschool? Anyway. Recently swapped out a fucked VF8 hybrid turbo for a VF10 hybrid (smaller exhaust housing for better spool) on the 1600cc B6T engine that's in my Laser TX3. One of the drawbacks of running the hybrid setup on the B6T is the internal wastegate ends up being too small, which leads to overboost. So when the VF10 was assembled, one of the things I made sure to get done was to port the wastegate and fit a larger flap. Think overall diameter increased from around 22mm to 28mm. New turbo has been fitted and runs fine... with one slight problem: adjusting the manual Go Fast Bits bleed valve to increase boost pressure only results in a measly 0.2 bar increase over standard (which is around 0.6 bar) with the valve fully open, even with a custom pinhole restrictor in the wastegate line. Before I rip it all out and go through the hassle of re-fitting my fancy Blitz electronic controller, can anyone shed some light on why the boost is only being increased by a miniscule factor? Could it be that the wastegate is nowe simply too efficient/large? Although I wouldn't think so, given that it only opens when the actuator tells it to, and I checked to make sure it was correctly pre-tensioned and wasn't swinging open of its own accord. Previously, with the VF8 fitted, ten turns of the bleed valve adjuster gave 1.1 bar, however the wastegate was not ported on this setup. With the VF10, ten turns gives no discernible increase over stock. Not quite game enough to pull the wastegate line completely off and freeboost all over the show, I have slightly moar respect for my car than that. Quote Link to comment Share on other sites More sharing options...
Testament Posted September 5, 2011 Share Posted September 5, 2011 are you using ALL the same hoses etc? what about the tee off the compressor side of the turbo? if that is larger then the bleed will do less/nothing. if you put a restriction between the compressor connection and the bleed/wastegate it will make the bleed more effective. In fact im pretty sure I remember doing that exact thing on this exact car way back when with some solder and a tiny drill at my uncles one time and then you ran 22psi? then the motor blew up or something? was that with the same VF8? Quote Link to comment Share on other sites More sharing options...
0R10N Posted September 5, 2011 Author Share Posted September 5, 2011 yeah that's the restrictor I'm using, you originally made it for my track car (with VF10). ended up swapping the restrictor over to this TX3 after I pulled the Blitz controller out and put the GFB controller in. All the hoses are the same, nothing has changed at all in that regard. Quote Link to comment Share on other sites More sharing options...
Dell'orto Posted September 5, 2011 Share Posted September 5, 2011 It is possible that the wastegate is too large/ heaps more efficient now. They do creep unlike external ones, so will bleed off pressure right from the outset. Quote Link to comment Share on other sites More sharing options...
0R10N Posted September 5, 2011 Author Share Posted September 5, 2011 Bah. Was afraid of that. starting to get extremely bitter about this stupid car. Quote Link to comment Share on other sites More sharing options...
Testament Posted September 5, 2011 Share Posted September 5, 2011 it's fine I'm sure. if you haven't fixed it I'll come by next time im up and we can sort it out in a few hours im sure Quote Link to comment Share on other sites More sharing options...
kpr Posted September 6, 2011 Share Posted September 6, 2011 haven't accidentally fitted the valve backwards? bleeds are horrible anyway. best cheap boost up method, spring always wins and is most stable: Quote Link to comment Share on other sites More sharing options...
Alistair Posted September 6, 2011 Share Posted September 6, 2011 Yup, go to the massive new spring section Bunnings has and grab a selection. Boost control at the touch of a spring! Quote Link to comment Share on other sites More sharing options...
0R10N Posted September 6, 2011 Author Share Posted September 6, 2011 haven't accidentally fitted the valve backwards?bleeds are horrible anyway. best cheap boost up method, spring always wins and is most stable Definitely fitted it the rite way. Anyway, I took it off and put on the industrial spec Festo ball valve from the track car, and that did the same thing as well (only 0.3 bar additional boost fully open). I then pulled the hose off altogether and went for a freeboost up the grafton gully onramp on the way home from werk. hello 1 bar at half throttle in 3rd so I guess it's efficiency related then, i.e. the bleed not having enough flow to fool wastegate into opening later. Would lubs to try the spring method but I cannae get to the actuator, it's hard up against the block maybe it's time to build a fancy restrictor canister, like teh one I saw in a book this one time. Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 6, 2011 Share Posted September 6, 2011 Sweet - at least you narrowed it down. Sorry I know fark all about turbos and wastegates etc to give any advice from here.. Quote Link to comment Share on other sites More sharing options...
kpr Posted September 6, 2011 Share Posted September 6, 2011 if can get up to required boost free boosting, just need to keep making the restrictor smaller. Quote Link to comment Share on other sites More sharing options...
Dell'orto Posted September 6, 2011 Share Posted September 6, 2011 You could try using one of those fancy pants Norgren valves, which will allow max control of the wastegate. Though I think they're pretty spendy Quote Link to comment Share on other sites More sharing options...
mjrstar Posted September 6, 2011 Share Posted September 6, 2011 ^^ You really need a dual port wastegate to get the best out of the Norgren relief valve set-up, although they can work like a normal old boost tap on a single port set-up. Quote Link to comment Share on other sites More sharing options...
SloNLo Posted September 6, 2011 Share Posted September 6, 2011 where is the restrictor? Quote Link to comment Share on other sites More sharing options...
0R10N Posted September 6, 2011 Author Share Posted September 6, 2011 Restrictor is between the turbo and the bleed valve. So turbo -> restrictor -> bleed valve -> actuator Quote Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted September 8, 2011 Share Posted September 8, 2011 i would put it between the bleed valve and the wastegate actuator Quote Link to comment Share on other sites More sharing options...
Hemi Posted September 8, 2011 Share Posted September 8, 2011 that ^ . Quote Link to comment Share on other sites More sharing options...
0R10N Posted September 12, 2011 Author Share Posted September 12, 2011 Is there a reason most topics on the subject specify that the restriction should be before the valve? Can't hurt to give it a shot with the restriction after the valve I guess. If anything, the bleed becomes the path of least resistance, amirite? Quote Link to comment Share on other sites More sharing options...
kpr Posted September 12, 2011 Share Posted September 12, 2011 i would think restrictor after the bleed, would only work if the bleed valve could flow more air than the supply hose. this way you also have more of a boost leak. i still think you need a smaller restictor in the same place as current one. is your bleed a straight through type or are you using a tee? if using a tee, even the direction of the tee will make a difference. Quote Link to comment Share on other sites More sharing options...
0R10N Posted September 12, 2011 Author Share Posted September 12, 2011 i would think restrictor after the bleed, would only work if the bleed valve could flow more air than the supply hose. this way you also have more of a boost leak.i still think you need a smaller restictor in the same place as current one. is your bleed a straight through type or are you using a tee? if using a tee, even the direction of the tee will make a difference. GFB tap, straight-thru type, one of these bad boys. It actually has a restriction already built into it, on the turbo side. The restrictor Testament and I made up all those years ago consisted of a screw head with a hole drilled through it packed with solder, then another pin-sized hole drilled through that. I've taken it out for inspection and cleaning, appears to still be the same. maybe a more robust setup is needed... solid brass tube with an even tinier hole drilled into it? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.