How much horsepower (boost) can a 44mm wastegate hold?

 

It should be enough for your 500r. I haven't had any problems up to 15psi on my gt35r. A lot of single turbo guys are running these with higher boost than me.

R.K.

 

Im going to take a stab at this one.

I dont think it has to do with how much hp a 44mm wastegate can hold. It has to do with the amount of excess air it can bypass to prevent overboost. Thats why, when it comes to wastegates the bigger the better. I have heard good things about the 44mm tial if thats what you are refering to, and thats what im going to be using on my T04R setup.

 

I know, that's why I put hp(boost). I know it's how much air they can vent, but hp and boost go hand in hand. What I am wondering is how much boost I can run. Next spring I'm gonna up the boost to around 22-23 and if Goodfello has really good results with his setup, I might go the same route. I think he is planning on running 25psi. I was just wondering what the boost limit will be around.

 

If you are currently running, lets say 20psi, and want to run 22-23psi later, then you don't need a bigger wastegate. Remember, the wastegate is in the exhaust, so if you want more boost pressure there will be less need to vent exhaust from the turbine housing.

You can actually have a wastegate that is too big. What will happen is that it will cause a sudden drop in boost when it opens.

Andrew

 

The question you should be asking is how little boost it can hold for a given turbo/manifold/motor setup. According to the person I spoke to at TiAL a few years ago, the 44mm flows more than the 46mm. I had no trouble keeping boost down to 9psi with my 35R compressor, street ported 2 rotor and 3.5" exhaust.

 

I get boost creep with my tial 44mm with a 10lbs spring just on the spring pressure....it holds until I start getting my rpms going, and then it creeps to 15, then to 22-23 lbs, lol, I need a bigger wastegate...might have to do with my free flowing exhaust 1.15 a/r and 4" all the way out.

 

Can i suggest that although people refer to hp as an indication, its not gd practice because its almost back to front, large wastegates can hold low boost required for low hp, but Small wastegates couldnt hold the a low boost setting.

There are three inportant factors to consider....

1) Turbine housing A/R plays a big role on shaft speed. Take for example to4 turbo running p trim with large 1.15ar housing. The 44mm wastegate will work well, but if you use a smaller .84ar housing the shaft and compressor speed will increase putting more work on the the wastegate to release more gas in order to slow down and mantain the same level of boost or shaft speed.

2) Turbine trim, This is the very important. Larger turbines need to be matched with larger wastegates. Having the area of the turbine exducer increase will need to be meet with a laregr wastegate. if the wastegate diameter is to small in proportion to the turbine. then it will have less abilty to control shaft speed or boost. I would suggest that the 44mm will be ideal next to the gt35 and p trim turbine. Larger trim may work if they are matched with large turbine housing A/R.

3) If you need to hold a low level of boost then you will need to use a large wastegate, especialy if the engine is ported. A ported engine will develop more exhaust signiture which will make it harder to hold low levels of boost.