To those with GT28RS
- Thread starter blthlt
- Start date
The problem is the wastegate flapper is loose, therefore creating an exhaust leak and not spooling the turbo fast enough. We are gonna take it off next weekend and see if we can't tighten the wastegate arm a little bit. On a side not his car pulls hard once he gets full boost.
BlAKECTX said:
Sounds like the wastegate flapper to me too. My stock one was s*** so I had to do some adjusting. I 've ridden a GT28RS boosted MSP and it very noticeable that boost takes a little longer to build compared the stock turbo but once it's going holy hell!
Yellow MSP
Member
- :
- 2003.5 Stock MSP
There really is no need for a video. Unless I am horribly mistaken, the T28 has the same housing as the T25, with just larger wheels. It should spool just like the stocker, just a couple hundred RPM's later. Jesus, even a 50+ lb/min turbo can be fully spooled before 5000. Do a boost leak check and check for exhaust leaks (a good way to do this is simply to cover the tail pipe with a rag or your foot (with a shoe on of course) as you can then easily tell where the leak is) and obviously verify that your actuator is functioning properly. Also make sure that all of your lined are hooked up right.
Yellow MSP
Member
- :
- 2003.5 Stock MSP
blthlt said:
No, what I posted was to check for exhuast leaks. To check for boost leaks I would do this:
The basic idea is that you want to fill the ENTIRE intake system post MAF to check for leaks. Anything before the MAF really does not matter (unless you have a gaping hole as you don't want debri flying into your combustion chamber).
To do this, you want to you an air compressor (I usually keep it up very high, like 100 psi or wherever it was, as it does not matter). So, you need a way to cap off the front end of the MAF while filling it with air. The way I do did this was to buy a coupler the size of the MAF (I believe 2"), which I actually went to Home Depot to the plumbing aisle and found a 2" rubber about 4" long or so. They even come with hose clamps on them (although t-bolts are always better). You just need it big enough to fit over the MAF and for the cap. So 3-4" should be fine.
Also in the plumbing aisle are PVC caps. You can find one that will nicely fit in the coupler. Finally, go to your local auto store (CAPS, NAPA, etc) and buy a tire valve (might come in a pack of 2) and some JB Weld (I prefer the Kwik
). Drill a hole in the cap just big enough to allow the groove in the valve stem (you will know what I mean once you get one) with some force. Once you know the size is good, mix up some JB and smear it around the stem where it will meet the cap. Try not to use too much as it will make it take much longer to dry. Then smear a the JB around the outside edge of the cap and tighten down the coupler as much as you can without breaking the clamp. Let it sit for as long as you can (at least a few hours, but a day would be best) as if it is not fully dry, the valve stem or cap could blow off under pressure. Once dry, take off the airbox (or filter) and clamp down your coupler, again very tight. Now two people work best if you have a boost gauge, as one can fill the system and the other can watch the gauge. If you don't have one, then you just need yourself. Let the compressor fill your system for at about 5-10 seconds to start. (You just need to make sure you don't fill it up too much, as you will blow out a pipe or something, so just a few seconds should tell you what you need to).
Then you need to get out your ears and listen for any escaping air. If you have aftermarket pipes, a coupler is a likely suspect. If not, the throttle body flange or a vaccum hose might be another culprit. If you think you hear something but can't be positive, mix up some very soapy water (the more suds the better) and pour it over the area. Then fill it up again. You will see the bubbles move from the air if there is a leak. Then tighten whatever needs to be, repeat, and you are done. This may sound complicated, but it really isn't. If you have a boost gauge, you want your system to hold a little more than what you are boosting (you said 10-12, so you would want them to hold 15 or so). So have a friend watch the gauge to make sure you can hold at least that much. Like I said, don't fill it up too much.
Hope this helps and you get it all figured out
cool thanks, great write up on a pressure check method. I vote this to be rewritten in a "how to" thread and sticky'd. I just wish there was a way to tell if my wastegate flapper is not closing all the way without removing the mani/turbo from the car....Any ideas?
