avatar382 Posted January 27, 2005 Share Posted January 27, 2005 So I got my TWE header installed today. Man oh man, it's awesome. During my drive home, I noticed a huge improvement in top end power. I redlined twice without realizing. The sound, too, is totally kickass!!! At the time of install, however, I did notice a lot more turbo lag, though - and I suspected a boost leak. Apparently, the TWE header moved my turbocharger back a centimeter and up a centimeter. A consequence of this is that the mechanic who did it had to grind down some metal around my downpipe, because the new turbo position caused the DP to rub the chassis, and my intercooler hits the hood so it won't close I get home tonight and try to install spacers in the sense of washers on my hood's latch, so even though it looks retarded (looks like my hood is open) I'll be able to close the hood securely without worrying about busting my IC or forcing it shut. I do that, and it turns out ok. I'm going to have to turn the dremel on the underside of my hood to try and get a little extra space where the IC is. With the hood up I notice that what looks like a large vacuum hose coming from the passenger side head is loose. I figure it might be causing the boost leak, so with a hose clamp I tighten it down. I get in my car and go for a drive. I notice after letting it warm up a bit and get on some boost that the boost lag level seems back to normal. I shift, and I hear a WHOOOSH like if I had a really loud BOV installed, and set to vent. My car has a 100% recirc bypass valve. This immediately threw me off. I didn't have much time to think about it though, since a second later, my car dies on the side of the road, and will not start. I open the hood and notice the little nozzle on the intake where the BPV is plugged into is broken. That explaned the noise, and the lack of starting.... I put the nozzle back in the best I could and the car starts. Whew, I limp home. A hole in the intake would stop the car from starting, right? Here's a pic. I'm wondering if tightning down that hose from the cylinder head was a bad idea. What is that hose for, anyway? I'm pretty sure it's in the right place... Purple = BPV Blue = the little nozzle that broke Green = the hose I tightened. It really sucks that the TWE pipes moved the turbo. In my case, it caused quite a pain in installation. Quote Link to comment Share on other sites More sharing options...
rallyruss Posted January 27, 2005 Share Posted January 27, 2005 the green hose is for the crank case pressure/vapors. yeah if the by pass valve fitting came loose or broke then yeah it wont run or run poorly. unmetered air bad. Quote Link to comment Share on other sites More sharing options...
avatar382 Posted January 27, 2005 Author Share Posted January 27, 2005 Well, I re-routed the BPV and it runs fine now. But, I seem to have lost a noticeable amount of low end. First and second gear don't fully spool the turbo until like 3500 rpm. Maybe I have an exhaust leak? Boost Leak? Or maybe it's just the 7.7 CR, cams, and the high diameter exhaust catching up to me? Quote Link to comment Share on other sites More sharing options...
JWX Posted January 27, 2005 Share Posted January 27, 2005 how big is the exhaust? on WJM's he gets full boost by 2500 or so. Quote Link to comment Share on other sites More sharing options...
avatar382 Posted January 27, 2005 Author Share Posted January 27, 2005 It's the same header, isn't it? I think. By "high diameter" I was referring to the larger diameter in the header itself... The low end torque issue I don't care about, it was never my car's strong suit anyway. It just seems like I've got a lot more turbo lag now. Maybe the wastegate was messed with on install? Or exhaust leak? Or boost leak? I gotta play with it. Quote Link to comment Share on other sites More sharing options...
JWX Posted January 27, 2005 Share Posted January 27, 2005 oh I thought you meant after the turbo. maybe the guy who installed it messed something up? another reason to do ones own work on their cars. Quote Link to comment Share on other sites More sharing options...
calebz Posted January 27, 2005 Share Posted January 27, 2005 The lag could very easily be caused by the oversized piping of the header. Can't really compare it to Will's lack of lag though.. you are running a bit bigger torbo than he is. Bigger turbo Low compression Too big header diameter all add up to increased lag. Quote Link to comment Share on other sites More sharing options...
avatar382 Posted January 27, 2005 Author Share Posted January 27, 2005 That's right, Will still has a stock VF7 turbo. Anyone running a VF11 like me or TD04 with the Techworks pipe installed? Quote Link to comment Share on other sites More sharing options...
JWX Posted January 27, 2005 Share Posted January 27, 2005 didn't even think about that. still say the tech might have messed something up Quote Link to comment Share on other sites More sharing options...
Vanislru Posted January 28, 2005 Share Posted January 28, 2005 Sounds about right, the td04 are meant for more exhaust flow/pressure, with the larger dia. header lag will increase about 300-500rpm, and almost that again with a td04. What boost press. are you running? I have a tdo4 but I don't think I will run it on either of my TWE piped cars I'm trying to make a franken turbo instead [td04 intake turbine into a moddified rhb5 intake snailshell. Stockers are not bad exhaust wise especially if you port the inside of the snailshell so exhaust has a smooth path to the wastegate valve to prevent boost creep, the main drawback is the rhb5's 5 intake vanes instead of a td04's 6, the tdo4's vanes are steeper and the secondarys have a better profile. The rhb5's vanes are so slack in angle that when you start running high flow/pressure you get large heating losses and inefficiencies from the restrictions caused by so much vane face being in the way. Quote Link to comment Share on other sites More sharing options...
avatar382 Posted January 28, 2005 Author Share Posted January 28, 2005 Something I mentioned at XT6.net and figured it would be worth mentioning here: The stocker has one pipe length for both exhaust pulses, ie., they both travel together. The TWE header has two, the driver and passenger side exhaust pulses travel independently, and only mesh at the very top of the uppipe. Wouldn't this double or at least significantly increase the effective diameter of the unit as a whole compared to stock? Here's a pic for reference, taken by Kevin: Regarless, it's an extremely worthwile upgrade. Even though the increased lag might mean a few lost drag races off the line, which a subaru was probably never meant for in the first place, there is a very nice powerband now starting from the mid 3's all the way up to 6500, which is as far as I dared take it up to (so far ). 3rd and forth gear have become much more usable, and the car drives more like a high performance machine (feels much faster, more powerful) in my opinion due to the much better top end. Before, the powerband got off with a very forceful kick from around 2800-3000, but around the high fours low 5's, it was time to shift due to a noticible drop in torque. The trade from that nice, violent shove to a more progressive, but steadily building thrust is well worth it. The only time I can think it would be better to have the low end torque of say and XT6 would be in an autocross situation, where the driver might be accellerating from standstill many times. We'll see how the car manages on the Dragon come June! Quote Link to comment Share on other sites More sharing options...
WJM Posted January 28, 2005 Share Posted January 28, 2005 You BETTER be at the dragon...and I will still be t3h fAst4r!!! Under normal driving...you get full boost at 2500...stock is ~2100. When everything is good to go (aka normal op. temp), TWE full boost at 2200~2300....stocker at 1700-1800. Ive got the stock VF7, and TWE DP. Got a 2.5 inch 3 way cat, that reduces to 2.25...then down to 2 inches...back thru a 2 inch glasspack...then its all over and out past the bumper with some pipe...2 inch. Same spooling action on the 2.5 inch pure straight, and the 2.5 with 2.5 glass pack that was on the car at the last dragon meet. VF11 is not much better at all than the VF7. TD04 is considered much larger than the VF7/VF10-11 turbos. But...are still acceptable to use with the EA82T with a teeny more lag....TD04 is next for me. Just need a good DP... Quote Link to comment Share on other sites More sharing options...
WJM Posted January 28, 2005 Share Posted January 28, 2005 oh and its been discussed a thousand times...but the header moves the turbo up and back so you can put a larger IHI/Mitsu turbo on it and not have clearance issues for intake/exhaust stuff. I never had any issues with clearance or what not....I DO with the DP was alittle higher up towards the body...it hangs a little low for those ocassional Rally excursions... Quote Link to comment Share on other sites More sharing options...
WJM Posted January 28, 2005 Share Posted January 28, 2005 The lag could very easily be caused by the oversized piping of the header. Can't really compare it to Will's lack of lag though.. you are running a bit bigger torbo than he is. Bigger turbo Low compression Too big header diameter all add up to increased lag. Im going to stop fooling around and TD04 this thing. Quote Link to comment Share on other sites More sharing options...
avatar382 Posted January 28, 2005 Author Share Posted January 28, 2005 oh and its been discussed a thousand times...but the header moves the turbo up and back so you can put a larger IHI/Mitsu turbo on it and not have clearance issues for intake/exhaust stuff. That makes sense, I guess I just missed the memo. It's just a pain because now my hood won't close right and I gotta get a dremel and make some space! Quote Link to comment Share on other sites More sharing options...
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