Lee Hockley Posted May 14, 2002 Share Posted May 14, 2002 I wonder if anybody may have any suggestions regarding a problem I have had since the beginning. Whether my boost controller is switched off or on, whilst in second gear and pushing it through the revs, at the point the boost pressure reaches 1 bar on my gauge it unexpectedly drops a few points (.4 ish) then begins the climb again. Occationally it does it in other gears. The second climb of boost pressure has more acceleration than the first, but that could be due to the revs I have reached. Anybody have any ideas ? Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted May 14, 2002 Share Posted May 14, 2002 Maybe pre-spool is not working on the second turbo so that when it comes online it is robbing some of the power until wound up and spinning. Does it feel like the drop is during the transition from single to both turbo's ? Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted May 14, 2002 Share Posted May 14, 2002 Did you not ask this a while back? Anyway... Sounds like the transition from single turbo to twin turbo. Could be sticky or faulty exhaust gas valve, recirculation valve (BOV), sequential control VSV (cannot remember the correct name) and a whole host of other tiny little actuators. I assume all pipes have been checked for leaks. All pipes are in their original locations (except the boost controller ones). Importantly the two pipes that go into the sequential control VSV (two parallel pipes, on top of engine, left hand side above the turbos). What is the max pressure for turbo1 and then what's the max with both turbo1 and turbo2 on line? So does it go 1bar (single), 0.6bar (transition), then 1.2bar (twin) or something? Also is this a Jap Spec, UK Spec, auto/manual, VVTi model??? Pete Quote Link to comment Share on other sites More sharing options...
Lee Hockley Posted May 14, 2002 Author Share Posted May 14, 2002 I'd have to say that yes it does seem to be when the first ends and second begins. Pete, you probably remember this issue, because you noticed it after adjusting my plugs when I visited you a couple of months back. Its hard to say what the max pressure is for turbo 1 because I have only 1 gauge. I can only assume is attached to turbo 2. The reading does like you say ... 1 bar at about 4k, drop to .6 or .5 bar, raise to max 1.3 bar. Is this normal then, or should be looked into ? I am still under warrenty, thankfully. Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted May 14, 2002 Share Posted May 14, 2002 No this isn't normal Lee. You might expect a tiny drop, 1->0.95->1.2 or something but not 40% drop to 0.6 or something. Most Dyno plots show a small dip but I do remember Mark Partridge in his VVTi Supra which had a large drop between turbos (not sure how he corrected it though) We put it down to the VVTi at the time. (This was at the Power Engineering Dyno about 1.5 yrs ago, some others may remember this. I know Branners will) I remember you and your car now (sorry for my short term memory propblems), and as I recall all your pipes were on correctly. But we didn't check those VSV and actuators. Try to get along to Leon Green in Watford or something. Pete Quote Link to comment Share on other sites More sharing options...
Lee Hockley Posted May 14, 2002 Author Share Posted May 14, 2002 Cheers Pete, I have something to go on. 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.
Note: Your post will require moderator approval before it will be visible.