CTT boost leak analysis

[lewisweller]

31 minutes ago, Zakowsky said:

Although I started this in the overboost thread, figured I’d end it here. Not a great ending really, but for others who might be doing the same. I finally replaced the diverter valves, and just a few notes on the job. Passenger side is obviously easy, but (in hindsight) the driver’s side can be even easier with the right tools, in that taking the wheel tubs out on the passenger side in a PITA on mine for some reason...well out is easy, getting them back in is a pain.

 

For the drivers side I messed with the top clamp for an hour with a variety of needle nose vise grips and pliers and such, then said screw it and went and bought one of these for 30$.

 

 

So not the standard straight ones which most places sell, got this in a set of two at Canadian Tire. Using the one with the angle in them it took me literally 30 seconds to take the clamp off and the valve out. Other tip is when you put the new valve in, put the pliers on the clamp before you install the valve. It ratchets, so lock it open, slide it over the hose, install the valve then slide it down. 30 minutes wasted before figuring that out too.

 

But before the results, does anyone know wtf this is? I took out the driver’s side valve and this fell out of it! A short steel tube, doesn’t look like part of the valve. Why would this be in there? I thought maybe it fell down the hose from what ever is above?

 

 

 

When I saw that, and that the wrong diverter valves were in there to start with (0 280 142 108, which is for an Audi) I thought the new ones (710P) would be the answer. Not so however. The wheezing noise was a bit louder and the 0-60 times a bit worse if anything. Here are the graphs:

 

 

So with new diverters I’ve learned for sure that the wheezing noise is just my wastegates opening. It happens mainly when I accelerate lightly and let up quickly, like it was getting ready to built up fast but gets stopped, and dumps out the air. Doesn’t happen with WOT. Putting one new DV in did drop the turbo start RPM from ~2500 down to ~2200, and putting the second dropped it further down to ~2010. But I paid for that on the other end, as now they don’t break 0.7 bar. But over all it holds boost better in medium acceleration, they kick in faster so I guess in typical driving they will be better. Just sucks to lose top end.

 

But what really is a bummer is when I am not WOT I can actually get better performance...here is a slow acceleration before going to about 3/4 throttle. Almost 0.8 bar! And holds better too.

 

 

There must be a reason for this. Any ideas, and does anyone know what that steel ring is for? I didn’t put it back in btw...thanks.

 

Steel ring wasn't in mine and I don't see what it is for either. I bet the new one didn't have it. 

As for the noises, yes having performance intake will let you hear the wastegates clearly. Thinking back to my mk4 golf 1.8 20v turbo which I modified moderately, Ecu, DV cold air intake, mounts, exhaust, whole suspension, brakes etc made a lovely whoooaaaa whosh on acceleration and lift off, with the lift off wastegate "chatter flutter" turning heads in the street .....ahh to be young and carefree. Lol

So yeah I think you noises are not an issue.

I don't understand the boost levels, sometimes 0.8 and then sometimes less? This has to be something in the Tuning, probably a poor tune at that. 

Try this to See the result: record pls the dash gauges also if possible. 

Start in 2nd in Manual, 

Hard WOT at 5k short shift to 3rd 

At 5k short shift to 4th (you'll be breaking all sorts of laws at this point) 

 

The result if everything is working ok should be the boost stays pegged at max. !

 

 

[Zakowsky]

Yeah, I have to say I do like the way mine sounds, as juvenile as that might be! When you combine the whooshes and the Fabspeed exhaust, which I like because it is quiet at low throttle, but roars at full, it’s a lot of fun. I’ll do some recordings starting in second and short shifting, and hey, that is what the scanner is for!

[Zakowsky]

So I short shifted at 5000 rpm, this is from second:

 

 

And this from first, going up to 4th:

 

 

 

Sure enough boost stayed up much better and was higher. Down side of course is the times are slower.

 

So I guess I should end this as a boot leak thread as I don’t think anything is leaking any more. It’s just the ECU tune combined with the turbo range. So I guess my next project will be re-mapping my ECU myself! But that will have to wait, as we leave in a few days for our cross country drive. Before I headed out tonight there is a new slight tapping noise, the secondary air injector registered a not ready condition, and the normally rock stead idle was wavering between 560 and 520. Combined with the slow leak from the torque converter seal and the home made center support bearing, I hope things hold together for the next 7000 km!

 

[lewisweller]

12 hours ago, Zakowsky said:

So I short shifted at 5000 rpm, this is from second:

 

 

And this from first, going up to 4th:

 

 

 

Sure enough boost stayed up much better and was higher. Down side of course is the times are slower.

 

So I guess I should end this as a boot leak thread as I don’t think anything is leaking any more. It’s just the ECU tune combined with the turbo range. So I guess my next project will be re-mapping my ECU myself! But that will have to wait, as we leave in a few days for our cross country drive. Before I headed out tonight there is a new slight tapping noise, the secondary air injector registered a not ready condition, and the normally rock stead idle was wavering between 560 and 520. Combined with the slow leak from the torque converter seal and the home made center support bearing, I hope things hold together for the next 7000 km!

 

Oops. Good luck. 

I'm arm deep into a repair on the Audi, Sunday it decided to overheat and I've diagnosed a stuck closed thermostat, quite common on these I've read. The repair is involved, with the supercharger having to come off amongst other stuff. Was nearly there and then disaster struck broke a coolant pipe which has 5 connections to it. So now have to squeeze in the tight space and remove a whole load of crap to get the broken pipe out. And hope there is one in stock somewhere tomorrow or I'm screwed for a week if coming from Germany. 

Some good news, I'm striking a deal with the guy who bought my Golf R, part X back the golf to me in exchange for the Audi and 40k cash in my favour. Will then sell the golf and clear a better return than just selling the Audi. Winner winner chicken dinner. 

[Zakowsky]

Well the CTT did hold out for the 7,800 km drive and it was in fact the most (mechanically) trouble free road trip I have taken! Ran perfect, no vibrations, tranny was fine, smooth and strong up to 150 kph (those prairies...) and I think the new diverter valves are starting to show a difference because it started making all the right whooshing and hissing sounds just like on TV. I also got so fed up with shopping for mud and snow tires I just took it off road (it was in part a camping trip) with the 285/35R22’s – hill climbs in the mud were no problem and actually used Special Terrain mode and the locks. Caught the outer edge of Hurricane Harvey at one point. Torrential downpour at night in high winds, the beast was amazing solid at speed through it all. So maybe these are worth the work after all!

 

[ekstroemtj]

Top! Good feeling to drive with confidence right?! The car looks nice with the wheels!