bugeyemilo

Get a tune and an exhaust, and keep the revs up.

jdexter

Don't forget the intake side. The new fender intakes with mafless tunes seem to be what everyone is doing now. I have flexible intakes and removed all the heavy restrictive bends in the oem intake. Big difference in spool!

pfbz

Checking for boost leaks should be #1 before ANY consideration of upgrades IMHO.. The turbos have enough headroom that they can overcome small and medium leaks and still provide "full boost" on the boost gauge, but spool time will definitely be affected, not to mention your making the Turbos work much harder than they should have to. When I pressure tested for leaks, I really didn't expect to find any leaks as my boost pressure was good and the car didn't seem excessively laggy (non X-50), but there were several that had likely been there since I purchased the car. Once fixed, it made a HUGE difference and the car spooled much faster.

That said, the X50's do have a fair bit more lag. And while you don't mention transmission, if X50 and Tiptronic, it can havequite an unpleasant amount of lag even with zero boost leaks.

jayzbird

pfbz

Disclaimer: I'm no expert, my experience is from boost checking my own car and a couple of others, plus all the great advice I've read from some of the tuners who offer their advice on Rennlist...
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1. Where are you pressurizing from? My best results when pressure testing was to connect to the intercooler inlet pipes underneath the car. Pretty easy to get to with a jack/jackstand or ramps.. Anyplace else and I was chasing phantom leaks like the oil cap. The turbos themselves will bleed air into the crankcase if you pressurize anywhere upstream of the turbos themselves.

2. The F-pipe(where your arrow is pointing) is a pretty common place to have leaks. I've seen them split on the bottom where you can't see it unless removed. Running your hand along the bottom of the F-pipe and listen for changes in the leak sound.

3. Looks like you have some aftermarket diverter valves? I've seen several threads where they also have caused some boost leaks...

4. If you are really holding 15 psi pressure for 30-60 seconds, thats pretty good. Even small leaks will bleed off pressure pretty quickly.

5. These are the test plugs I built and used... Super simple and effective, but the correct size PVC plugs were not available at the typical lowes/homeDepot. A well equipped ACE hardware had them. These babies, some soapy water in a spray bottle, and careful listening found all my leaks pretty quickly. A couple of guys make much nicer ones out of metal that are less likely to "pop out" under pressure, but if your in a hurry and don't want to wait, these worked fine.

jayzbird

pfbz

Maybe there is a split in the hose right where the clamp is? You could also try using a worm-drive hose clamp instead of the spring clamp and see if it's just a matter of how tight it is, but my guess is that your f-pipe has a small split in it that you wont be able to spot until you pull it off completely. Or perhaps your aftermarket diverter has a small crack in it.

Personally, I'd just swap in new diverter valves (710N diverter valves, about $40 each) and a new F-pipe (I used a Forge silicon F pipe, about $68). These parts are known failure points and it sounds like there is a good chance one of them has a failure rather than just not seating properly...

You are pressurizing pre-turbo, and you probably don't have the correct size plugs to pressurize from below, but IMHO it's well worth the effort to find some 2.5" pvc plugs shown above and test from the intercooler inlet. You will save a ton of time chasing down issues that are not relevant as otherwise you are pressurizing areas that do not see boost pressure.

.

If I recall, the f-pipe can usually be worked off without lowering the engine, but your aftermarket diverter valves might be making it more difficult. It's quite easy to lower the engine slightly once you know how... Put a jack under the engine to support it, loosen the lower engine mount bolts, but keep them threaded on the mounts at least a few turns, then gently lower the engine.

It's often easier to spend a few minutes slightly lowering the engine than dealing with the cursing and knuckle-scraping often required without lowering...

"02996ttx50

don't underestimate the possibility of having a leak at the #16 check valve at the plenum. pressurize on your test to about 20 psi and might even hear the leak.

32krazy!

if you testing at 15 psi thats not enough. leaks show up ay higher pressures that you dont see at lower ones. also test from the compressor side of the turbo so you can see if theres any leaks from the turbos themselves.

fwiw i test at 40 psi but my car runs max at 35 psi

jayzbird

32krazy!

Just watch it doesn't take your head off at the t/b if testing there!

Kevin

Over the years, the number one request for UMW is.. How can I lower the lag on my X50.. And yes tuning and a exhaust will help. But a similar rated tuned K16 fitted with the K24 X50 compressor wheel will out accelerate and develop more torque/power vs the "STOCK" K24 (earlier in the RPM curve) and match it to redline.
For the street the K16 and K16 hybrids are better suited vs the X50 K24's.. If you have the road and high speeds (well over 130 mph) the K24's begin to shine.
The new 991.1TS has "tiny" turbine wheels KO4 sizing.. 3/8" smaller diameter vs the K16 turbine wheel. And develop 580HP with a LARGER engine.
The 997.1TT has the very same 991 turbine wheel and shares are same basic engine and is 480HP out of the box with the TINY turbine. Massive engine torque is generated and limited by the ECU with this arrangement.
I am not ******* the K24's.. They have there place.. But for day to day street driving where you can't get over 100mph the K16 hybrids in my opinion make more sense.
FYI, the worst is a X50 Tippy configured as CAB (extra 300lbs)..

A little 996TT folklore. I designed a new K24 turbine wheel that didn't have the turbine wheel blade clipping. I see 300 RPM lag reduction (w/all stock exhaust/tuning) 600 to 700 RPM lag reduction tuned with exhaust. On one of my 996TT, I am running this combination in machined K24 cartridge in a machined/ported K16 turbine housing (nice lag reduction)...

Dock

You're a Wizard.

jayzbird

"02996ttx50

16/24 is the optimal turbo configuration for a street driven dual duty car.