• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Boost Gone Wild

I have the turbo off and the hotside housing off. I am going to try to port the wastegate opening by about 5mm. My very rough cowboy/internet CFD calcs tell me that will increase flow by almost 100%. I also intend to knock down some of the very thick part of the casting on the ex manifold side that seems to direct flow past the wastegate port. I will post before/after pictures of the work and report if it works.
 
You guys are pretty close concerning the open 3" exhaust being the culprit. It is indeed part of the problem here.

"The best exhaust for a turbo is no exhaust" (well, almost)...we've probably all heard this. It is mostly true. A diverging nozzle, basically a long shallow cone, would ideally be the best exhaust straight out of the turbine.

But your tiny turbine with tiny wastegate port and large open exhaust system are effectively acting like "no exhaust" (system) is present. What this does is reduce the turbine pressure ratio needed to produce the shaft power required to drive the compressor. Which is great, as long as you can control boost. By reducing post-turbine restriction we are actually asking the turbine wheel to flow more. If you look at a turbine map, we are above the choke flow curve the whole time here since the wastegate is open. Power required by the compressor hasn't changed, and lines of constant power are diagonally arranged on the turbine map, going up as you move left.

The turbine operating point went from a high pressure ratio, above the choke curve on the flow axis, to a lower pressure ratio (lower on x-axis) but to a higher flow condition, even higher above the choke curve on the y-axis.

Increasing your corrected turbine flow means that a small wastegate port might reach choke, and therefore even if the wastegate valve is wide open, turbine power won't be reigned in enough to control turbo speed (hence boost). This is known as boost creep.

At low engine speeds & lower loads, before you hit peak boost, you would likely notice a difference in power & response if you drove the car with the wastegate valve wired shut vs. flapping in the breeze. If you removed the actuator and left the valve crank arm free, the valve would open way early and you'd reduce your available turbine energy and feel a difference in both power and response.

The key is that once you reach full boost in this case, even with the wastegate valve in the turbine housing completely open, that opening can't flow enough.

Potential solutions:
  • Upgrade to a larger turbocharger or bigger turbine housing that flows more. Either way, more turbine flow capacity.
  • Port the ever-loving crap out of the wastegate, opening the port hole diameter, adding a radius at any sharp corners. This may not ever be enough however.
  • Add restriction to your exhaust system. Smaller tubing diameter, or add a cat or a muffler. That will increase turbine pressure ratio and bring overall flow back down, to a point.
 
If you're using the car for crap can racing (guessing from your avatar), grab a t3/t4 60 trim or TO4E turbo from ebay. Slap the ATP ultimate wastegate on it. Have more fun and more reliability.

After a lot of mental masturbation on this topic, it seems that the T3/T4 is the least effort / best chance for success approach. Help me understand some things if you will:

1. Advantages of the ATP waste gate vs. some other waste gate that might come on a complete turbo on ebay? If I use the ATP WG, can I use the actuator off my 13c (I have 3 of those now)?

That is, this: https://www.ebay.com/itm/T04E-T3-T4-63-TURBO-TURBOCHARGER-COMPRESSOR-300-HP-W-INTERNAL-WASTEGATE-V-BAND/202730000062?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D225086%26meid%3D94706ecce6e64b62800275e8808ddffd%26pid%3D100677%26rk%3D4%26rkt%3D30%26mehot%3Dpp%26sd%3D153721731550%26itm%3D202730000062%26pmt%3D1%26noa%3D0%26pg%3D2386202%26algv%3DSimplAMLv5PairwiseWeb&_trksid=p2386202.c100677.m4598

vs this: https://www.ebay.com/itm/T04E-T3-T4-63-TURBO-TURBOCHARGER-COMPRESSOR-300-HP-W-INTERNAL-WASTEGATE-V-BAND/202730000062?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D225086%26meid%3D94706ecce6e64b62800275e8808ddffd%26pid%3D100677%26rk%3D4%26rkt%3D30%26mehot%3Dpp%26sd%3D153721731550%26itm%3D202730000062%26pmt%3D1%26noa%3D0%26pg%3D2386202%26algv%3DSimplAMLv5PairwiseWeb&_trksid=p2386202.c100677.m4598

2. The term "60 trim" I think refers to the exhaust manifold interface? Is that right? Does it relate to a specific measurement?

3. A/R ratio. What should I look for?

4. Does a T3/T4 use the coolant lines that the 13c does or do I cap them off?

5. What should I expect to have to modify for the oil lines?

I really appreciate your help. Thank you in advance.
 
I blew the seals out of one of those in a couple months. Only weekend driving autocrossing, but I was running 22+psi. I don't recommend it. I ended up putting this turbo back on it after about 3 years of similar use, there was some wear on the impeller tips, but it's still making a lot of power. I welded on a V Band for my 3"exhaust though so not sure what you'll do with a stock exhaust connection. I also had to reclock it.https://www.ebay.com/itm/124224296182

Edit: I forgot your problem came from your 3" exhaust. I bought the kinugawa oil feed kit but I had a custom drain line made.
 
If you want to come down to San Clemente, I can show you my T3/T4 setup on my Lemons car. The turbo is actually removed right now so it is easy to see. I went from Garrett T3 to the T3/T4 setup.

I used this turbo: https://yoshifab.com/store/t04e-50-trim.html

If you are going from a Mitsu to Garrett style I think you will need:
- Manifold modification to match the turbo flange and new 10mm studs. https://yoshifab.com/store/volvo-manifold-t3-conversion-service.html
- You will also need to figure out hardware to keep the turbo attached to the manifold. So far I have tried several methods, but at the end of the race turbo is not tight to the manifold and leaking precious boost.
- Mine is water cooled, I used the existing lines and banjo connections.
- Oil feed. I used a -4 AN feed line. -4AN to 1/8 NPT on the turbo side, M14 x 1.5 on the block
- Oil return I used a -10 AN line. Bought an adapter for the turbo side on ebay, Yoshifab -10 AN adapter on block.
- I kept the stock 2.5" wastegate, I think you need a 3".
- I don't know what you have for intake tubing, I used a 3" to 2.25" reducer and 2.25" joiner to connect to my stock intake from siliconintakes.com
- My tubing from the turbo to the intercooler worked with some minor adjustments.

Even with my wastegate wired open, this setup will boost up to about 12 PSI at 6,000 RPM, I don't what it will do with 3". I put a 12 PSI actuator on it for the last race and it was nice.
 
After a lot of mental masturbation on this topic, it seems that the T3/T4 is the least effort / best chance for success approach. Help me understand some things if you will:

1. Advantages of the ATP waste gate vs. some other waste gate that might come on a complete turbo on ebay? If I use the ATP WG, can I use the actuator off my 13c (I have 3 of those now)?

That is, this: https://www.ebay.com/itm/T04E-T3-T4-63-TURBO-TURBOCHARGER-COMPRESSOR-300-HP-W-INTERNAL-WASTEGATE-V-BAND/202730000062?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D225086%26meid%3D94706ecce6e64b62800275e8808ddffd%26pid%3D100677%26rk%3D4%26rkt%3D30%26mehot%3Dpp%26sd%3D153721731550%26itm%3D202730000062%26pmt%3D1%26noa%3D0%26pg%3D2386202%26algv%3DSimplAMLv5PairwiseWeb&_trksid=p2386202.c100677.m4598

vs this: https://www.ebay.com/itm/T04E-T3-T4-63-TURBO-TURBOCHARGER-COMPRESSOR-300-HP-W-INTERNAL-WASTEGATE-V-BAND/202730000062?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D225086%26meid%3D94706ecce6e64b62800275e8808ddffd%26pid%3D100677%26rk%3D4%26rkt%3D30%26mehot%3Dpp%26sd%3D153721731550%26itm%3D202730000062%26pmt%3D1%26noa%3D0%26pg%3D2386202%26algv%3DSimplAMLv5PairwiseWeb&_trksid=p2386202.c100677.m4598

2. The term "60 trim" I think refers to the exhaust manifold interface? Is that right? Does it relate to a specific measurement?

3. A/R ratio. What should I look for?

4. Does a T3/T4 use the coolant lines that the 13c does or do I cap them off?

5. What should I expect to have to modify for the oil lines?

I really appreciate your help. Thank you in advance.

I like the ATP gate as it flows so much better than the traditional internal WG setups that you linked to. You might be able to get the 13c actuator to work if you?re stubborn/motivated/cheap enough.

Trim size is in reference to the size of the inducer/exducer of the turbine or compressor wheel. In this case, 60 trim refers to the compressor side.

For turbine AR, I?d recommend 0.63 or so for road racing. It?ll keep everything a bit cooler vs a 0.48 housing. You might be able to go to a 0.8-ish housing as well depending on what RPM range you run the engine in. Higher AR number usually means slower time to boost, but the housing will flow more exhaust and will work better at higher revs.

You can find water cooled t3/t4 turbos, if you want to use one. Which might make sense with pit stops and driver changes in endurance racing. The 13c coolant lines will not work in my experience, but you can use parts of them to adapt new lines.

For oil lines, you can make or buy a simple oil feed and turbo drain setup. I think Kinugawa makes one, and you can also source your own stuff for cheap if you?re da military with the parts.

Depending on the budget you have for this upgrade, ATP sells Garret t3/t4 turbos and can set you up with a kit that will work well for you. It?ll be ~$850.
You can also go with an eBay turbo (get one that?s VSR balanced) and then add on the ATP gate. That would run about $250-400.
 
A trip to San Clemente is likely in my near future. Having eyes on what works is always beneficial. Thank you for the offer.

I've elected to give the waste gate porting one chance. Here is the before and after of the porting:


mostkYel.jpg
wFsbtA1l.jpg


I measured the waste gate port at just under 18mm before I started. I ended up just over 26mm when finished. I also cleaned up the path to the port on the exhaust manifold side. There was a bump in the casting that seemed to me would push the flow past the port:

ddvpHtjl.jpg


Based on what I have read, I do not believe there is a good chance this works but given that my cost to try was a little of my time, I thought "why not?" Any last thoughts before I bolt this together this coming weekend?
 
That looks exactly like what I did on my old 13c. It ran fine with a short 2.5" open downpipe.
 
I did here.

http://forums.turbobricks.com/showthread.php?t=356443

I might just weld the hot side to the manifold.

Well, it's easy to go down the rabbit hole with the Miata guys on this.

I've looked but cannot find a B230 exhaust manifold/header that has a vband connection to the turbo and an external wastegate port. That would solve almost everything.

Does anyone on TB forums make custom B230 headers?

Like thishttps://i.ebayimg.com/images/g/340AAOSwJmVbzj-4/s-l400.jpg
 
I know Josh at Yoshifab has a guy that makes custom headers for him, but that seems like another rabbit hole. I am not sure how well they will stand up to 24 hours of straight racing.
 
I was able to install the ported wastegate exhaust housing on the turbo and reinstall but for the downpipe connection (ran out of time).

Something of note: by chance I noticed the magnetic response of the factory manifold-to-turbo studs was low. Relative to @rb9267e's issue with his turbo coming loose after extended periods of high output use, are the factory studs (8mm) made from ss or some other exotic material? It's certainly different than the nuts and most of the other hardware in the engine compartment (touches everything in the engine compartment with a magnet)

In case you missed it, the guys who put turbos on their Miatas and take them to the track have this problem. Online, they have a never ending argument over how to solve it. Also, they argue over Inconel is or is not the same as/as effective as A286, cutting vs rolling threads, safety wire, stage 8 nuts vs nordlocks, NASA approved high temp threadlocker and more. Google it if you have a schadenfreude kink.
 
In case you missed it, the guys who put turbos on their Miatas and take them to the track have this problem. Online, they have a never ending argument over how to solve it. Also, they argue over Inconel is or is not the same as/as effective as A286, cutting vs rolling threads, safety wire, stage 8 nuts vs nordlocks, NASA approved high temp threadlocker and more. Google it if you have a schadenfreude kink.

I did read all that. My manifold/turbo is drilled for 10mm studs. I have tried studs from an auto parts store, probably Dorman, with locking copper nuts, they backed out and broke off. Same studs, drilled and safety wired with copper locking nuts, they came loose. Studs sold as A286/Inconel (I know Incenel and A286 are two different things) with Stage 8 nuts, no resbond, came loose.

Mazda RX7 studs are allegedly Inconel, haven't tried them. I also haven't tried nordlocks.

I just rebuilt the turbo and engine. Maybe it was one of those.
 
The studs are backing out or stretching? Or the nuts are coming loose?

I did read all that. My manifold/turbo is drilled for 10mm studs. I have tried studs from an auto parts store, probably Dorman, with locking copper nuts, they backed out and broke off. Same studs, drilled and safety wired with copper locking nuts, they came loose. Studs sold as A286/Inconel (I know Incenel and A286 are two different things) with Stage 8 nuts, no resbond, came loose.

Mazda RX7 studs are allegedly Inconel, haven't tried them. I also haven't tried nordlocks.

I just rebuilt the turbo and engine. Maybe it was one of those.
 
Back
Top