I am debating if I should plumb by MVR wastegate or not. Ive done a year of road racing so far and no issues but now that I have my motor out I am considering it. I dont like to over-engineer things and this may be a case of that. I have a HKS/XS cast manifold and it sticks the wastegate far down where air hits it.

With that said, I am curious to know how many people have fired their diaphragms and what their setup was. Also, post pics of where the coolant feed and drains taps are.

 

Never, not once have I cooked any of the MVS or MVR wastegates I've sold or personally used. Unless you're doing competitive professional road racing you won't come close. Make sure the wastegate/wastegates are in good locations and you should have nothing to worry about.

 

I've got a customer than has gone through about 9. It is a road course car that sees 20plus minutes of wot, before a cool down lap/pit stop. His main issue is too small of a turbine wheel and housing however. They are a maintence item for road course cars regardless.

 

I've seen the same thing as Elliot with an autocross car.

 

Thankfully Elliot suggested that I go with the 1.0 A/R TD61 so I dont think high EGT #'s caused by a small turbine will be a big issue. My wastegate gets a lot of airflow and I am not going to exhaust wrap my wastegate plumbing. Hopefully this way it will last a few years.

 

Good subject! This makes me want to route fresh air from air dam to the wastegates.

 

Elliot and Chris, was this with the water cooling? If so they must be getting cooked afterward by the radiating heat in the engine bay. I still have yet to have a problem with a Tial. Also, not related to you two but there are some REALLY REALLY good fakes out there.

 

Last autocross i did had lap timez of 40 seconds or so. With atleast 5 min in between the 14 runs i did w/ the corvett club.. Scca does 7 runs on the same track. I dont see how that guy is making as much heat as the guy doing 20 min track sessions of hard driving. So I do have some doubt about these issues. But just to be safe ill probably.run brake duct tubing from front air dam to wg area so they can get fresh air.

 

The cooling ports were not connected.

Doesn't really matter what your experience has been or what you think mine should be. The questions was, has anyone cooked a diaphragm? My answer is that I have seen, first hand, a dedicated autox car cook multiple diaphragms in short order. To the point the owner carries spares to events and has had to make changes at events.

All that said, it's a special circumstance, like Elliot describes in his case, where there is a very small turbine housing and associated back pressure. Back pressure has not been recorded but EGT is actually acceptable at a little over 1600* peak and steady through a full load pull. The owner reworked his manifold for this season to move the gates into an area where they should run cooler; hopefully exposed to less radiant heat. We'll have to wait and see how it works.

 

Usibg logic here.dont have real experience. But!! Water cooled gates dont have the longer necks nor the amount of heat sinks compared to a typical non.water.cooled gate. Why wouldnt they use the water cooling ports. This might fall under user.error.

 

What are some symptoms of a failing wastegate diaphram? slow spool or low boost?

Here is a picture of my MVR wastegate with a thousand miles (4 track days and few dynos). Again, I have a 1.0 A/R p-trim t4 turbo, 3.5inch catback, re-routed DP, unknown EGT. NOT WATER COOLED.

 

A torn diaphragm will cause boost creep, or at least boost pressures above spring pressure. For a Tial, the diaphragm is in the top aluminum housing under the spring.

 

When i have time, im planning on taking take it apart and take few pics.

 

Buy a high quality waste gate (I like HKS) which cost more but it will last a decent amount of time and you won't have to plumb things which allows for the magic of KEEP IT SIMPLE to envelop itself into your car.

I went through 2 tial diaphragms in 3 years and then through it in the trash can and bolted on a old HKS wastegate no problems in 2 years (fingers crossed). When the diaphragm goes the gate stays closed and you over boost and that's not a good thing.

If you notice your boost going up it could be your diaphragm failing so be careful and don't pinch pennies on this very important part.

 

Tial makes quality products that are very tried and true...if you use it as designed.

Directly from Tial's website...

Water cooling is not required for typical street car applications. Water cooling is required if:
- You road race the car CHECK for OP
- You have low/no airflow in your engine bay True for most single turbo RX-7's
- Your downpipe/exhaust manifold comes close to the top hat of the wastegate True for most single turbo RX-7's
- Rotary applications are not required to run water but highly recommended CHECK

So running the coolant seems pretty mandatory to me...for all rotaries (street or track).

 

Quite possibly.

 

The old Tial wastegates were a lot larger and could dissipate heat better, but of course they took up more space. When the MVR and MVS gates came out, they were more compact but couldn't dissipate heat as well, so they came with water cooling ports.

 

Those HKS wastegates surely do cost a pretty penny! At almost $700 I think I may just stick with the MVR and plumb it. For that big of a cost I may just forget about enveloping simplicity to my car lol.

After all these comments I am really considering plumbing the wastegate. Only thing bugging me is deciding where to connect the drain. The feed will come from the rear iron port which was used for the throttle body.

 

Could you tell us which Tial WG's models you had?

 

I am in the process of running some coolant lines to my MVR. I will post some pictures soon of how I am doing it.

 

I got it from Sean at Aspec 3 or 4 or so years ago so don't remember specifically but it's the little 44 that he was selling with all his kits in those days.

AGAIN I recommend the HKS racing wg it's what works for me.

HKS Racing Wastegates from Alamo Motorsports

 

This is how I ran my coolant lines. Tapped the Throttle body coolant feed from the front waterpump housings. I used 1/4 NPT to -4 fitting. For the drain, I tapped the rear iron throttle body port 1/8 NPT to -4. Then made custom stainless AN lines. If you dont mind getting rid of the coolant lines to the throttle body this is pretty easy.

 

So, is there any suggested inspection interval for street driven applications? I'm running a 1.0 T4 divided TD61 with dual Tial 38s. I've had this setup in the car now for about 4.5 years. Setup has between 8-10K miles on it so far.

 

This is my recent parallel feed for my dual MV-R waste gates. Feed from the radiator return and return to just in front of the thermostat housing. All 4-AN teflon braided hose.

I did this to solve a bad creep problem on my original single waste gate manifold design.

1. My "Remora" recirculated waste gate exhaust.
2. You can see the feed line from the radiator return to the Tee fitting for WG coolant feed and turbo coolant feed. Also top left is the Tee for WG return.
3. The rear WG and return line up to the return Tee fitting.

 

^^^Mighty nice handiwork Dale!