CMonakar

My turbo manifold is finally done, BUT as usual there's a problem. The fabricator used a TiAL 44mm wastegate instead of the HKS GT II 60mm that I originally speced. Apparently he couldn't find enough surface area on the collector to weld the 60mm inlet pipe on. My options are (1) give the 44mm a shot or (2) cut apart the top of the collector, add a spacer to it to create enough room for the wastegate, or (3) buy another $400 Burns collector. (2) & (3) will be very costly because I will also have to remake the downpipe and the turbo support bracket-which basically looks like a mini suspension control arm.

Here is my setup

-Large street port
-GT42R 102mm with a 1.15 exhaust and T6 footprint.
-4" straight through exhaust

Think a 44mm will be able to keep the boost down below 10psi? If anybody has experience with a similar setup please chime in.

mcfly

i would ask zero r at a-spec

he should know the answer since he deals with the gt42r often.

mad20b

Nope - I had the identical setup on mine - 6 psi spring boosted to 22 psi or something from memory - I had to borrow a 60mm gate from a friend. I ended up running the main pipe from under the turbo as per the 44mm set up & then run another 2 runners from the back 2 housings to the piece of pipe that I flared to 2.5". Works well - its no piece of art though...

CMonakar

Yikes. What was the minimum boost you could run with just the 44mm setup?

mad20b

Couldnt control the boost at all

t-von

iTrader: (8)

I think the location of the wastegate (regardless of it's size) plays an even bigger roll than most people think.

Quadulus

I bought my 20b GT42R turbo kit from Zero R and it came with a TiAL 44mm. You should be ok.

mad20b

I guess you are just going to have to try it & report back to us!

CCarlisi

Based on everyone's feedback I decided to have another fabricator try to find a way to fit the 60mm. Thanks to everyone that replied. I'll post pictures of the finished result when I receive them.

4CN Air

iTrader: (7)

wow on a 20B? You must have a huge turbine housing.

With a street ported 13b and a Turbonetics Progate I can't keep a 62-1 (.88 a/r) regulated to 16psi.

black93RX7

t-von: you mentioned the position of the wastegate may play a large role in how it operates, what do you consider to be an ideal position?

My manifold has the wastegate very close to the manifold runners, can't even fit my dump tube on, since it would hit the subframe.

Options are to extend the dump tube, which I dont think I'll due or addd an extension to move the wg further back.

Any suggestions, I'll try and post some pics tommorow

RETed

With a project as money intensive as a 20B install, you're getting cheap on the wastegate???
I wouldn't use anything less than a Tial 46mm / HKS Race 50mm / HKS GT 50mm / HKS 60mm GT.
And even then, I'd worry about some creep...


-Ted

Whizbang

a local on his 4G63 colt w/ a GT42R used two Tials. work quite well. held at whatever he set it too. (usually 30 at the track, 20 something street)

4CN Air

iTrader: (7)

I'm currently debating between two tial 38's or 1 HKS 60mm GT (actually a copy from eBay, then use HKS springs)

Actually the ones in that pic are from XS Power, he must have doen the same thing (I hope he used tial springs)

Whizbang

i beleive he used tail springs but the setup worked *VERY* well.

Zero R

iTrader: (1)

The biggest problem with assuming because someone has creep it means the WG is too small. People always tend to run a larger wastegate than necessary this causes more lag and more oscillations of the power delivery. Running twin wastegate allows for a larger valve to diaphragm ratio this is good as it will modulate lower boost well. But it has room and plumbing and hookup headaches. That said when you try and control boost with a large wastegate it will tend to crack open early bleeding off the stream sooner and causing your turbo to spool slower. Then when you let off the throttle you practically stall the out coming stream, the wastegate starts to shut and the turbine slows. Then start all over again once you get back on it.( Think of the same principle as running a larger wheel on the turbo. Bigger items move slower )Now with a smaller gate and a POV on the IC side the wastegate doesn't "bleed off" as soon, so..... spool is quicker, response crisper. When it opens and your at say 1bar with the 44mm it will open quicker, any other need to bleed off boost is handled by the POV. This will then also assure the turbo does not drop off in speed when you stall the exhaust stream because there is less resistance in the intake plumbing. So you stay in boost and the motor will breath more like a N/a powered car. Running a smaller wastegate and a POV is much better at smooth crisp power delivery over running one large gate, or trying work out a solid twin gate setup. It has been more than proven by professional race teams for years.

-S-

paximus

iTrader: (1)

Recomendations on a POV?

been thinking about this as a safety measure...

Zero R

iTrader: (1)

HKS and Greddy both make them. Greddy's is pretty cheap and simple. The HKS one is more adjustable I think, and I believe is dual purpose if I remember correctly. I'm going to be trying out theirs soon. (I haven't used theirs yet.) The other benefit is it is much more adjustable as a system. Example, you can run a stiffer spring pressure if you wish than the what the POV is set at. So if you want to run 1bar, then run 1bar on the POV and 16lbs on the gate. This will allow for boost to ramp up quickly as the gate will stay shut longer, then use the wastegate to open later, the gate will start to crack open before the 16lbs as it is. This way you are using the POV more to control boost and the gate more to bleed of manifold pressure only as needed. I look at it less as a safety device and more as a better mthod of boost control.

felix_is_alive

bringing this thread from the dead .......does anyone have pics of this setup ??
I am running a Turbonetics T76 with 1.15 A/R Q-Trim on the hot side ,street ported engine i am getting boost creep like crazy with a tial 46 MM , i have no boost control att all , i have even tried to use a 2.5 psi spring so in case it overshoots , it wount go as high , all i did was give the car more lag and at about 6~7K RPM it moves to about 13~14 psi ,
I did a search on the POV idea , (which i taught to be brilliant ,plus easier for me to do ) but i got a lot of negative comments with this ,that it would make my turbo spool too high without need and eventually making the turbo fail prematurely
I really want to try it tough ,any suggestions?
I am just trying to get my facts straight , i dont want to take some "kids" advice on the forum and go explode my car , but you got a good rep and seem to have youre **** together so , also if anyone else would like to give their 2 cents ....welcome

rarson

Well, I know pop-off valves are commonly used on applications like the Porsche 951, but I don't like them, basically for the reasons you mentioned. I like them more for overpressure protection, instead of boost control.

I don't think using a POV for boost control is wrong, but I personally wouldn't use it like that.

My question would be though, are you SURE you've got the wastegate hooked up correctly? I'm not trying to hint at stupidity or anything, but a Tial won't blow open as easily as something like a flapper-door internal gate. I can't say from experience, but I would think a 46mm would be big enough for a 20B. Maybe not.

C. Ludwig

iTrader: (27)

The Tial 60mm is finally available FWIW. I talked to Sean about using the 60mm on the 20B header. He said the 44mm is plenty. Seems like he should have some good experience to back that up.

mad20b

The 60mm tial is well priced too! I CAN speak from experiance & neither the 44 or 46mm are big enough.

mirabile

ASPEC also told me that 44 is enough for my GT42R. I will know within a week or so and report back. Others have sworn that dual 44s or a 60 is needed. I am trusting the brothers at ASPEC.

C. Ludwig

iTrader: (27)

Keeps us updated. I'll be ordering my manifold from A-Spec sometime soon.

felix_is_alive

ok this is the situation , as stated before i have the 46 mm (tial) setup with a 2.5psi spring , i have no boost controller hooked up or anything ,just plain wastegate ..........the car starts to build boost from low rpm i can see some movement from about 2500 rpm (difficult to see since its a 2.5psi spring) it holds there up until about 4000/4500 rpm , then the boost rises to abot 10 psi (real real fast)and if i keep moving the rpm`s up ...say 7K i would be around 15 psi ,thats when i let go ......so i am thinking this is more of a question of flow then anything else (again i am waiting to be corrected on this as i am not shure) it could be manifold design but i have seen manifolds with similar designs as mine so i am not 100% that could be it , i will post pictures of my manifold later today .....i am not shure and i guess the guys at ASPEC should be much more of experts than me , but i dont trust the 46mm i think it cannot flow enough air to control the boost
And yes i am already looking into a tial 60mm they look pretty good and are pretty good priced so ....
its just funny that on a well build supra (i know its no comparison with this but just a general idea) we once used a racegate (piece of ****) which is pretty small or smaller than the 46mm in any case , and it would handle boost decently , but the 46mm on the 20B couldn`t do it for **** (at least in my case) , do our engines really have that much exhaust flow?