zeeboost Posted August 29, 2009 Share Posted August 29, 2009 Alright, well I've had coolant leaking from my headgasket for a while, so I replaced it with a 1mm Kameari metal headgasket. The previous gasket was a nissan competition 1mm metal headgasket, so compression should still be the same. When removing the head, I noticed that the top half of the tension-side timing chain guide had broken off, and it was laying in the bottom of the cover - god knows how long it's been like that. After cleaning everything the best I could, I replaced the chain guides and reset the cam/crank timing. The only thing I changed (from what I can tell) is I adjusted the cam sprocket from the 1 to the 2 setting. In doing this, I had to tweak the cam a hair to get everything to line up. The new turbo I installed is a turbonetics T4 - .6* hotside and I don't remember the compressor specs. It's been over a year ago since picked it up. Anyways, after having everything installed and driving it around, the car feels a bit more sluggish, and seems to bog/lug down when driving around without boost. As soon as it hits boost it'll scoot, although still seems a bit more sluggish than when I had the factory T3 on there. So, if you've made it this far, here's my question: Where should I start to correct the sluggish problem? Should I tweak the cam/crank timing any? Or should I adjust all the VE tables and timing charts all over again? I would think that the VE tables aren't the problem, since driving under vacuum is really where it feels sluggish, and I'm assuming the new turbo shouldn't have effected the driveability under vacuum-only conditions. But, this is my first turbo upgrade, so I'm not sure what to expect - that's why I turn to you guys. I'll be messing with it tomorrow, so I would appreciate any quick responses. Thanks! Quote Link to comment Share on other sites More sharing options...
zeeboost Posted August 30, 2009 Author Share Posted August 30, 2009 Well, after driving it for the day, all I can add is under boost, at 8psi this thing screams, and roasts the tires through 2nd gear on a hot day (something that only 15psi with the factory turbo could achieve). But, geeezus the lack of low-end power is killing me. Maybe I should at least try moving the cam sprocket from the 2 back to the 1?? I don't know, but it takes forever for the new turbo to spool up. That, and the idle is a couple inches of vacuum lower...FWIW. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted August 30, 2009 Share Posted August 30, 2009 I wouls start by moving the cam back to the original position. You made a few changes all at once, so it's difficult to pinpoint what changed how it drives the most. FWIW, my set-up was pretty sluggish, when going to large throttle changes, like from cruise to 50% or greater throttle position, played with AE, both TPS and MAP based AE tables, without much improvement. I started playing with my timing table over the last week, and made some vast improvments in driveability and most noticebly, the transition from high vacuum into boost. Most of the timeing table I advanced. You will also be hitting parts of the VE table you likely didn't before so they will likely be less than idealy tuned, with the later onset of boost, you may find that the low KPA at higher RPM cells are being used now, as opposed to before where boost would come on quicker, and use the higher KPA cells at lower RPM. First thig first is put the cam back to where it was, you should notice your idle vacuum come back up to where it was before. Quote Link to comment Share on other sites More sharing options...
zeeboost Posted August 31, 2009 Author Share Posted August 31, 2009 I was a bit hesitant to put the cam back in the 1 position, because I was thinking it would help me out in the top end. The only thing is I don't know if it shifted my power curve forward, or if it's hindering the entire power curve. I thought that the cam sprocket was only numbered for chain stretch. Not knowing how many miles my chain has, I set it on the 2. After searching the archives, I've read a lot of conflicting info about it either being used for cam timing or chain stretch...maybe I'm interpreting it wrong? I just got back in from driving it again, and I'm starting to have T3 withdrawals - full boost doesn't hit until 3600-3700 rpms . The turbo was a turbonetics T04e that I attempted to rebuild, but ran into way too many problems, so I sent it off to a shop. The shop used the same compressor housing and wheels, but they replaced the centersection and the turbine housing due to excess wear (which there was). I got the turbo back from them and had it in my garage for a few months before I ever opened the box. When I finally got around to installing it, I noticed the exhaust flange was a T4, but the size of the turbine housing was still relatively the same. I've been told it looks like one used on a Grand National, whatever that's worth. So, with this being my first full T4, I have no clue if this is normal for boost to be hitting at 3700rpms. Clifton helped me out in choosing the turbo, saying it will hit my power goals without much lag at all, but I don't know what difference it would make when switching the turbine housing to a T4. Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted August 31, 2009 Share Posted August 31, 2009 Having a T4 exhaust housing is going to slow spool down a good bit. Is there a AR number on it? should have like a .(insert number here) on it. Do you know what exhaust wheel they put in it? 36-3700 rpm's sounds reasonable for a full T4 turbo. It is a trade off from the T3. The T3 will have instant spool but fall on its face at like 5K. With this turbo it sounds like you have full spool by 3700 but I bet you can make more power closer to 6-6500rpms. Quote Link to comment Share on other sites More sharing options...
zeeboost Posted August 31, 2009 Author Share Posted August 31, 2009 I thought the a/r was .58-.62 ish - right in that area IIRC. I'm about 200 miles away from her right now so I can't check the turbo housing, but it's sized properly for decent spool. The Turbine wheel is still the O-trim that it originally came with as a T04e. Just think of it as a Turbonetics T04e with a T4 exhaust flange. As the original t3/t4, it was supposed to have very quick response time with very little lag (again, Clifton is the one that directed me to this one, and the man knows his turbos ) You're correct - once I'm in full boost, it blows its way to 6k in no time, but waiting for it to build boost is already getting old. It just feels like something is off. Even driving on the highway under vacuum is more difficult, as in it takes more effort to keep a constant highway speed than before. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted September 1, 2009 Share Posted September 1, 2009 What does a cranking compression check show with the new cam timing? Quote Link to comment Share on other sites More sharing options...
zeeboost Posted September 1, 2009 Author Share Posted September 1, 2009 It never occurred to me to check it, however, I don't know what it was before. Quote Link to comment Share on other sites More sharing options...
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