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beepbeep beepbeep is offline
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Join Date: Jun 2001
Location: Sweden
Posts: 5,564
1st: what people generally call "turbo lag" has actually at least two compontents: boost treshold (influenced by capacity, turbo sizing and plethora of other deatils) and inertia lag itself (influenced mainly by shaft weight)

2:nd: What you now feel as 'lag' might be the headroom you feel after updates. What I'm trying to say is: before the upgrades your power jumped from approx. 120hp off-boost to 300hp on-boost. Now you installed bigger ports (=less air velocity at low revs=less torque off-boost) and your power probably jumps from something like 100hp to 370hp (yes, it's a crude approximation but you know what I mean).

So yes, you both gained high end and somewhat decreased the torque at off-boost low-end due to bigger ports. Add the possibility that your ignition timing might not be optimal and yeah, you might feel increased lag.

As I said before, if you measured the lag period before/after It would probably be the same but as you now get a whole lot more it feels like lag is bigger.

There a couple of ways to decrease the lag. You could try a more modern turbo to start with. Garrett GT35R is a splendid design. Shorter headers help as well. You can also retard off-boost ignition and shorten the spool-up time (but you will pay it with less torque off-boost). Everything is a tradeoff.

Most extreme method is by using WRC style anti-lag. It can give you no-lag full boost all the time but it won't last long
Thank you for your time,

Last edited by beepbeep; 05-09-2007 at 04:14 AM..
Old 05-09-2007, 04:12 AM
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