When is 2 wastegates required

[SpoolN]

Just ordered a stage 3 block from slowboy, and a stage 6 head from them as well. Motor is going to be reved to about 8500-9k. I want to run either a gt37r or gt42r, would a tial 44 mm wastegate be ok, or should I run 2 38s dont know the benifit of running 2 or if it would be benificial. Any help would be nice.


Thanks

 

[awdtalontsi1992]

A 44mm would be ok. The two 38mm gates would be overkill and alot of extra piping. The simple 44mm gate will be more than enough.

 

[SpoolN]

A 44mm would be ok. The two 38mm gates would be overkill and alot of extra piping. The simple 44mm gate will be more than enough.

K just wanted to make sure before I go manifold shopping... What is the purpose of running 2?

 

[CanadianTSi]

Some people run two when they run a divided inlet turbo.

 

[SpoolN]

Some people run two when they run a divided inlet turbo.

The 42r I have been looking at is so would this require 2 or would running the 44mm still be ok?

 

[biglady112]

Yes, very neccessary on a divided turbine. You will have very serious issues with that turbo with boost creep and boost control. We run dual 44mm's for ease of servicablity.

Steven

 

[PSI NRG]

Its just a preferance.... Ive seen guys who run 42rs run one wastegate. The key is that you need to have a dump off each side of the divided manifold. Now whether you choose to run dual 38mm off each side or have two dumps come into one and into a 44mm is up to you

 

[SpoolN]

Yes, very neccessary on a divided turbine. You will have very serious issues with that turbo with boost creep and boost control. We run dual 44mm's for ease of servicablity.

Steven

K thanks for the info

 

[Kevin Jewer]

Its just a preferance.... Ive seen guys who run 42rs run one wastegate. The key is that you need to have a dump off each side of the divided manifold. Now whether you choose to run dual 38mm off each side or have two dumps come into one and into a 44mm is up to you

Many people are concerned however that joining the two halfs of the divided manifold/housing with the WG piping defeats the entire purpose of having the divided setup. I tend to agree, but I have no personal experience with such setups.

 

[Steve93Talon]

The HKS cast T4 manifold is a divided outlet and has a single wastegate port, plenty of people have run just fine with it.

 

[94awdcoupe]

I would just ask Buschur since you are buying the motor from them and get there opinions on it. You could also call AMS as well and see what they say.

 

[SpoolN]

I would just ask Buschur since you are buying the motor from them and get there opinions on it. You could also call AMS as well and see what they say.

I'm not getting the motor from Buschur it's from Slowboy

 

[Slow99x]

What type of trans are you planning on building? I hope you are not going to subject the poor stock trans to that type of turbo. I personaly think that if you need to ask these types of questions AS you are putting this setup together, I would reconsider and go with a smaller setup untill you have some more experience and knowledge. Just because you can afford it doesn't mean you should do it. Maybe start with a 30r because if you screw up in your tuning or something else, your motor will be more forgiving than with the massive power of a 42r.

 

[oztofrdm]

What type of trans are you planning on building? I hope you are not going to subject the poor stock trans to that type of turbo. I personaly think that if you need to ask these types of questions AS you are putting this setup together, I would reconsider and go with a smaller setup untill you have some more experience and knowledge. Just because you can afford it doesn't mean you should do it. Maybe start with a 30r because if you screw up in your tuning or something else, your motor will be more forgiving than with the massive power of a 42r.

theres no need for that he's asking a question that i myself am still courious about. It looks like you have two choices when you run a divided housing, you can either run two wastegates ie. two 38mm. or you can run one 44mm that connects both the divided pipes together. I guess it all depends on how baller you wanna be and what manifold you wanna run.

As for the tuning part, if something bad is gonna happen its gonna happen. My tune was perfect then i started pusing the stock block to the limit one day the wrist pin broke off of the piston and threw the rod out the back of the block. The smim blew open and the wiring harness cought of fire. The point of my story is that if shit is gonna go wrong its gonna go wrong, yes the more power you push the better the chances are that something is goning to happen. At least he is doing it the "smart" way and building it first.

 

[topstreet]

The way I would put it is: " keep it simple stupid" I am not insulting anyone, its just a phrase.

I run a single wastegate on a divided manifold with the 2 tubes joining. This has be just fine for me. VERY consistent boost control and no troubles.

As far as connecting the two... I didn't really think about this before but, I would say that you are not really looking to have really heavy, and nice flow out of these tubes as you are the primary header tubes. The pressure is going to be released as much as the wastegate is allowing it to be. The primary charge is going to go in the turbo and create a venture affect. The end result is that I do not think it will impede the manifolds performance to have it this way.

The other way to look at it is... It works for me? If that says anything.

Jake H

 

[SpoolN]

What type of trans are you planning on building? I hope you are not going to subject the poor stock trans to that type of turbo. I personaly think that if you need to ask these types of questions AS you are putting this setup together, I would reconsider and go with a smaller setup untill you have some more experience and knowledge. Just because you can afford it doesn't mean you should do it. Maybe start with a 30r because if you screw up in your tuning or something else, your motor will be more forgiving than with the massive power of a 42r.

We are going with an ipt tranny. We arent gonna use the stock tranny what so ever. As far as tuning we arent tuning it ourself. We are going to have someone tune it for us. It was a simple question that I wasnt sure about becuase I have no run a turbo near this size. As far as a 30r my buddy ran one and we know that we want to go bigger than that.

 

[biglady112]

We run two 44mm's on their own seperate tubes. 1/4 have a wastegate and 2/3 have a a wastegate.

Steven

 

[GILZTSIAWD]

Ever thought about going between the 37 and 42 and maybe going with a 40? I am going to be running a 40r here soon along with slowboy's SLS manifold they sell that runs dual 38mm wg's. If you order one of these manifolds be prepared to wait, its been almost 11 weeks since I placed my order and am still yet to receive it. As soon as it comes in and I get the car together I'll let you know how the setup works out, but I am sure you will probably make a purchase before then.

 

[Kevin Jewer]

The HKS cast T4 manifold is a divided outlet and has a single wastegate port, plenty of people have run just fine with it.

I'm sure that is true, but it does nothing to disprove the theory that a single WG tube joining both halves defeats the purpose of dividing the manifold. Perhaps they would have done better with a true divided setup? AMS and Shearer, as quick examples, use manifolds that use two WGs. I'm sure the added complexity, cost, and packaging ####ery is worth the benefits if they are doing it. Some of the fastest DSMs and EVOs on the planet use manifolds from those guys.

 

[topstreet]

Kevin- In good taste with the intension of exploring this idea...

What is the purpose of a divided manifold or turbo. My understanding has always be that you can separate the exhaust pulses. Therefor, one side can get hit and then the other. This is constantly egging the turbine wheel on, and causing it to spin. The alternative would be just to let the 4 pulses come in any way they want to.(4-1) The difference in a design like this is very simple.

If you have 1.65" inside diameter piping, and it then hits a 4-1 collector... There is a moment where the exhaust pulse has to jump into a chamber which has... Lets just say its a 3" diameter at the top, and then tapper down again to about a 2.5" ID. This pulse is going to also be pulled through by the last charge and pushed by the next. It is also slowed down by the rapid change in pressure.

In a divided were cyl. 2-3 are joined and 1-4 are joined... The 1.65" primary charge has to jump into alittle less then double of the original tube size. BUT it has one full exhaust stroke to wait before the next charge comes through. So... they are always alternating. Left, Right, Left, Right.....

Even though it may seem like it, we are not looking for a wastegate to flow... At least no where near the amount that the header tubes and turbo housing are. Therefor, if the wastegate is not flowing the same amount, it is going to create a pressure barrier in the manifold, at the point where it joins. This is barely going to interrupt exhaust charge if it is done right. Infact, I have even seen the cars they use in Indy running an entire manifold bank to the wastegate alone.

Either way, I guess the conclusion that is in my mind is that joining the two sides together is not really going to disrupt anything.

Jake

 

[94Jettameowpsst]

I was always under the impression that 2 wg's are only necessairy on a large frame turbo (regardless of wether or not its a twin scroll) if you're trying to run low boost levels. There are plenty of people on the supra forum that run a single 44-50mm wg on a 4780r that try to run 16-18psi and they just cant do it.

 

[SpoolN]

Ever thought about going between the 37 and 42 and maybe going with a 40? I am going to be running a 40r here soon along with slowboy's SLS manifold they sell that runs dual 38mm wg's. If you order one of these manifolds be prepared to wait, its been almost 11 weeks since I placed my order and am still yet to receive it. As soon as it comes in and I get the car together I'll let you know how the setup works out, but I am sure you will probably make a purchase before then.

That was our original intention, was to run a 40r we talked to buschur before our motor purchase and they said they they didnt really like the 40r and you are better off to get a 42r for pretty much the same ammount of money. We are still up in the air with the whole turbo/manifold situation. I just know the smallest we plan to go is a 37r. Def. keep me in the loop when you get your set up going.

 

[CrazyGSX]

people get this two wastgate thing out of your head its just not for are cars.
you run two wg for v8 cars ithe two turbos end of story, and buy the way the biger the turbo the smaller the wg.

 

[CrazyGSX]

just to note. big trucks like mack and motors in othere stuff with cat power, some of it dont even have wg's, the turbo slows down quickanuff they just dont need it. yet they are not pushing 25psi and are not reving 9000rpm, but they have piston big as coffie can's and push alot of air to the turbo at 4500rpm. its just when you let off the gas there less air to the turbo,
so the turbo slows down. thats why you dont need a big or dual wg'S.

 

[Slow99x]

If you have a devided turbined inlet you SHOULD run a dual wastegate setup. How will you controll boost on the side that will allow exhaust gas to still pass over the turbine wheel and continue to spin it? Unless your wastegate is on the turbine housing itself or on the downpipe you might boostcreep. I do agree with the statement about bigger turbos needing smaller wastegates though.