Wastegate upsizing

[seattlejester]

So it is official, I have uncontrollable boost.

 

Setup is 2jzge NA-T, 2mm head gasket to bring compression to 8.5ish to 1

Treadstone T4 cast stainless manifold

Preision 39mm wastegate with a 9.4lb spring

BW S257sx-e with AGP 0.7A/R hotside

 

Backstory:

My friend with a smaller hotside on a T3 manifold holds 10lbs with a poor priority on a 40mm wastegate on his 2.7L single cam motor. I decided since I wanted to run a bit more boost at around 15lbs or so I should be ok with the 38mm wastegate flange. I even got the precision 39mm which boasts a 1mm oversize.

 

After help from Chickenman to finally figure out my boost control situation, I set my manual boost controller to 0 and went out for a drive.

 

In first and second gear it is holding 10lbs of boost. Once I get into 3rd if I go more than 30% throttle or so it starts creeping all the way to my boost cut which I have set at 17lbs.

 

So now I'm kind of stuck. My cast stainless manifold has a 38mm wastegate two bolt flange cast into it. They do make a 38mm to 44mm adapter, but logically to me that would not work since the restriction of the 38mm wastegate flange would still be there. 

 

What should I do? I know I need to upsize my wastegate, will a 44mm be sufficient? Or do I just go big now? I imagine I can shave down the flange and bore out to the waste gate v-band size and just weld a stainless v band directly onto the the manifold, but I know stainless is going to be terrible to work on. I don't even know if tradition style bits would work if they even made one big enough in the first place.

 

 

[Chickenman]

Before you buy anything else. Try putting a lighter Wastegate spring in. The 9.4 lb spring  may not be allowing the W/G poppet valve to open 100%. Try a spring combo with a 7 lbs rate. You can go all the way down to a 3 lbs if you need to. 

 

If you have any restrictions to W/Gate flow ( bad entry angles for example ) then you may have to use a lighter spring combo than necessary to get the Valve opening more.  Simply because the exhaust flow to the W/Gate is not optimal. W/Gate positioning and entry angles for exhaust play a big part in controlling  Boost. Get them wrong and the W/Gate will be inefficient

Edited March 12, 2018 by Chickenman

[Chickenman]

Can you post up a wide angle shot of your W/gate manifold and exhaust setup?  Proper angles of W/Gate inlet pipes and outlet pipes can make a huge difference to W/gate efficiency as noted above. Right angles and reverse angles are bad.   

 

 

 

Edited March 12, 2018 by Chickenman

[rossman]

Chickenman covered it but you might want to also consider your wastegate outlet pipe too.  If the outlet is routed to a high pressure or very turbulent location in the exhaust pipe it will affect the efficiency of the wastegate.  You could test this pretty easily by dumping to atmosphere like a screamer pipe.  If the boost becomes controllable then you found your issue or at least part of your issue.

Edited March 13, 2018 by rossman

[seattlejester]

Thank you guys for the response, I must have missed them.

 

I'll grab a wide angle shot this weekend.

That is where the wastegate is mounted.

That is unfortunately how the wastegate dump merges back with the exhaust, it is probably one of the worst ways of merging to be honest. I tried to tilt it so it is not perpendicular, but I couldn't get it very far from what I recall. There just is not very much room unless I try to do a full 90* turn and follow the exhaust for a little bit, but then I run into interference with the heater bypass hose if memory serves. 

 

I might believe that the wastegate was opening plus or minus 3lbs of the rated spring, but I've been told precision gate springs are pretty solid. Swapping the springs doesn't cost me anything though, so I will give that a try. 

 

Edit: found another picture. 

Looking at that seems to have jogged my memory. I seem to recall that the 90* bend actually hit the turbo dump pipe when it was turned to follow along with it. So short of resorting to pie cuts for a really sharp 90*, this was the only option I had. I can try a screamer pipe setup, but I fear that the only way to do so would be to go up through the hood because of the previously stated interference. I'll go and take some measurements this weekend.

 

[Chickenman]

Yeah... I can already see what is probably the Major problem. The manifold design. That is a worst case scenario for W/Gate placement on both the W/G inlet and outlet.

 

Inlet is 90 degrees and only bleeds 3 cylinders, if that.  The manifold looks like it's possibly a Twin scroll design. Is it? Either way, it;s going to be hard to bleed off enough pressure with that exhaust manifold W/Gate positioning. 

 

On the outlet side it is worst case scenario as well. 90 degree exit into the high pressure area of the Turbine outlet. If you could re-route the Dump pipe, that would help a lot. Length doesn't really matter. You could route it another 2 or 3 feet further along the exhaust system, then blend it in at a nice angle. 

 

Problem is just getting it past firewall.  With a long W/Gate dump pipe, you may want to run an  accordion style expanding bellows, as the dump pipe will expand in length a fair bit. 

 

Things like ovalised SS tubing may help. Or using a 90 degree adapter, so W/Gate exit is towards firewall, then run dump pipe behind exhaust manifold, beside the downpipe and Transmission? It looks like you may have enough room to do that?

Edited March 15, 2018 by Chickenman

[Chickenman]

Would have been nice if the exhaust manifold came with a V-Band adapter. Would open up options for W/gate clocking. 

 

This is what I was thinking about for a 90 degree adapter.

https://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=ATP-FLS-025&Category_Code=WGEL

 

Or is you want to switch to a V-Band mount W/Gate. 

https://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=ATP-FLS-101&Category_Code=WGEL

 

 

Edited March 15, 2018 by Chickenman

[Chickenman]

One other thing. Don't over look porting of the exhaust manifold W/Gate outlet. This is commonly done on Internal wastegates, but the same principle can be  applied to the Manifold port for an external Wastegate. You can port to gasket size and do some blending of sharp lips to aid flow. Every little bit helps. 

Edited March 15, 2018 by Chickenman

[Chickenman]

Another Option may be to change Turbine housing for one with Internal W/Gate. That gets rid of external Dump pipe and fitment issues.  Last resort type thing. Just thinking.... 

[seattlejester]

Almost looks like the manifold would have made sense with two wastegates and being truly twin scroll. As it is now it has a bit of a ramp where the exhaust enters the turbo, but it is about an inch or two from sealing. I want to say there is an aftermarket flange adapter type thing that does divide it into a twinscroll, but that would only compound my problem.

 

Not sure the reason, the only one that makes sense to me is for a QSV, but even then I'm not sure.

 

Technically like 87* :D, the more I think about it the more I feel like there was a reason it was done that way given how unideal it is. Not sure if it was to keep access to the bolt or just the room for the turn. I do recall being startled by the lack of space. That 90* adapter might be something. Although I'm not sure how far I can go straight back given how far I placed my motor in the engine bay.

 

The waste gate adapter did catch my eye for stepping up to a 44mm and getting the infinite clock-ability of the V-band. I think the concern with that style is that the hole still remains at 35mm according to some diagrams online. That would mean needing to port the adapter and might as well the manifold, and if that is the case might as well just weld the included wastegate flange from a 44mm wastegate directly to the manifold after porting it to match was my thinking. Not even sure how you port cast stainless. Only thing that was worked before was tungsten carbide bit on a dremel and that took ages just to do a couple mm on a flange.

 

I'm not sure if the hotside change is an option. The only BW turbos with wastegates are the EFR turbos, and even then my spacing is fairly tight.

 

I think the first step will be to take some measurements, then see if there are options. I'll swap springs, but I think the setup prevents this size from working. I think a wastegate change and exhaust rerouting might be in order.

[Chickenman]

For porting you will need more than a Dremel. I use a 1/5 HP , 20,000 RPM Craftsman electric grinder. The good ol' Model 315 with 1/4" shank and Ball Bearings. And a lovely all metal housing that will try to electrocute you when you plug it into an improperly grounded wall socket. Ask me how I know... 

 

Air grinder will also work, but you need a decent size compressor to feed them. 1/4" shank Carbide cutter and HD grinder would be the way to go. If the hole size out of the Manifold is only 35mm, then that does need to be enlarged. 

 

Dump pipe re-routing is definitely necessary. 

 

You could do a screamer pipe straight out of the side of the fender. Just like Street Outlaws... LOL

[seattlejester]

Hmm, would something like this work?

https://www.amazon.com/Makita-GD0601-4-Inch-Die-Grinder/dp/B001ASC73E/ref=sr_1_1?s=hi&ie=UTF8&qid=1521140870&sr=1-1&keywords=electric+die+grinder

 

Then again, I wonder if a machine shop could drill out the hole for a less than the cost of that tool.

 

I think my endgame plan will be picking up the precision 46mm wastegate, match the flange to the V-band, then clock the waste gate so that the pipe goes out and enters the dump pipe at a 90 degree to the turbo exit (follows the bend of the dump pipe), so that it goes along the curve and gradually blends into taking maybe 3-4 inches to do so.

 

There is a childish part of me that would find a screamer pipe entertaining, but a bigger part of me finds that to be a bit too much theater.

 

Hopefully this solves this and we can finally move onto tuning. 

[Chickenman]

That's a good grinder. It will pay for itself the first time you use it. Tools are always a good investment. 

 

 

Edited March 15, 2018 by Chickenman

[softopz]

Before moving the wastegate entirely or rerouting the dump longer try buying those flexible dump pipes and essentially a screamer pipe.

https://www.ebay.com/itm/35mm-38mm-Wastegate-Flex-SS-Dump-Pipe-Kit-Stainless-Steel-weld-flange-Gaskets/173209341778?hash=item285414cf52:g:zp4AAOxy4YdTTWPX&vxp=mtr

 

Your piping looks too short right off the bat I am suprised with this treadstone design honestly its off center and the angle is not optimal. If you do eventually do re route your dump further into downpipe with non flexible joints you should put atleast a flex joint / expansion joint.

https://www.ebay.com/itm/38mm-1-5-OD-Wastegate-Stainless-Steel-Flex-Exhaust-Pipe-Dump-Cutout-Valve-4/173204765939?hash=item2853cefcf3:g:bm8AAOSw~gRVxMzY&vxp=mtr

 

Remember your manifold / turbo and downpipe  depending on location or material will shrink and or expand all differently. 

[seattlejester]

Wow, I didn't even know that was a thing. I wonder how much flex it could handle.

 

Just to get this straight.

 

The suggestion is with the current 39mm wastegate, cut off the current wastegate dump, cap the turbo dump pipe of the hole, add the flex hose, and see if the 39mm would work at all, basically testing the turbulence theory correct? 

 

I know for divorced setups you do want a bellow or a flex joint, if the wastegate reroute takes place it will definitely be that way.

 

The current half measure in my mind is to actually take off the hood, cut and patch the turbo dump, then install the nub of the wastegate on inverted (so it screams to atmosphere) to see if it can hold boost as well.

 

 

[HuD 91gt]

FYI find out if that grinder has any speed control. I bought one similar (from a well known Canadian box store, it’s home brand) and was slightly dissapointed to only find out it only runs at one RPM. I think you can buy an external speed control device a la harbour freight. 

[Chickenman]

Those external speed controls are great. I bought one for all of my corded tools. E-Bay. 

[softopz]

15 hours ago, seattlejester said:

Wow, I didn't even know that was a thing. I wonder how much flex it could handle.

 

Just to get this straight.

 

The suggestion is with the current 39mm wastegate, cut off the current wastegate dump, cap the turbo dump pipe of the hole, add the flex hose, and see if the 39mm would work at all, basically testing the turbulence theory correct? 

 

I know for divorced setups you do want a bellow or a flex joint, if the wastegate reroute takes place it will definitely be that way.

 

The current half measure in my mind is to actually take off the hood, cut and patch the turbo dump, then install the nub of the wastegate on inverted (so it screams to atmosphere) to see if it can hold boost as well.

 

 

Yes cut off , cap it (* you dont have to weld it maybe some thin sheet metal clamped down with some tbolt clamps just to test the theory . The reason I suggest this maybe so you dont spend more on a complete redesign of manifold, wastegate, and downpipe.

 

I have seen many adapters that do the wastegate's off at 90 some people do have issues with compressor surge and boost problems but not every setup is the same. Also at the same time lots of people do run it with no issues.  I didnt know till last summer street racing a 700hp DSM he had a flex dump. I dont think the quality is the best to be honest. However, I suggested this to troubleshoot and quickly see if the issue is your dump being to short * which I think it is * . OR if the issue is the wastegate angle which probably could be combination of both.

. 

How flexible it is I dont know. But I do have a similar stainless steel flex tub for my radiator piping and you can make a decent tight radius but Yours looks super tight. 

[softopz]

If you dont want to spend the money with the flex tube I would go straight ahead and modify that dump , Make a tighter radius fit it between manifold and downpipe and have it merge into downpipe with flex  or dump it to atmosphere. Even if it doesnt solve your issue its still more

* optimal

* have to worry about thermal expansion cracking/distorting your exhaust setup

 

 

edit also if you need more room what about a spacer at turbo a halft inch just at turbo would do wonders down stream. 

 

attached is how I would do it.

Edited March 16, 2018 by softopz

[softopz]

Sorry for multiple post but here is another idea would solve both wastegate location and dump pipe length. Depending if you go A or B Get this or 2x for bends and length

https://www.ebay.com/itm/Wastegate-Dump-Tube-For-Tial-38MM-35MM-Pipe-Actuator-Turbo-Racing-Exhaust-dump/122003842169?hash=item1c67fee479:g:GJIAAOSweIlZaF-a&vxp=mtr

you can do two things with it.

A. cap your old wastegate hole, Make new hole underneath manifold at collecter at 45 angle, weld straight tube leaving the flanged end for your wastegate, your second pipe could be used for your dump either merge or dump. I know it cast a friend of mine welded my l28et manifold just needs lots of pre heat / after heat for welding so it wont crack!

B use the pipe to bolt on to manifold, you may need to make some pie cuts or section it to make it the wastegate go underneath manifold and make new dump with your old flanges and piping. 

 

Attached are my old wastegate/downpipe setup. Notice the tight angle and location of wastegate inlet from cylinders 3/4 I had no boost issues at all ! with a gt35r/38mm tial and stroker motor. The only reason I changed it completely is the flange was touching my new intake manifold.

 

The new setup is like how I suggested A go.