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Discussion Starter #1
I had an idea come to mind this morning while in my early morning fog.

For a little background:

2.0L ecotec
S362sx-E T4 open 0.88ar

Current full boost is around 5500rpm

It's a street/ half-mile car. Ran the battle creek speedfest and won the fwd class with 162.4mph


The lag is killer even though top end is insane. I do have nitrous I can ramp up/down via boost to kick up spool, but would like to not rely on the bottle without having to drop to a t3 housing.


I had looked at the Sound Performance quick spool valve, but the price tag and forum tales of poor longevity turned me away. Then this idea came to me. Running a 4-1 to one side of a split housing, with a large gate dumping to the other side at 10-15#.

Same concept; no worries or durability. I searched for a while and all I could find was this picture:


It's exactly what I had in mind. I wish I could find more than just a picture. Thought maybe some of the old school guys here who have been doing this longer than I've been alive might have seen something similar, or at least some thoughts as to how well it would work.


Thanks
Al
 

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What does your header look like now?

That style seems like it would be really hard to incorporate with a 4 cylinder.
 

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Discussion Starter #3
What does your header look like now?

That style seems like it would be really hard to incorporate with a 4 cylinder.
It's on a T4 log manifold right now that I made myself. If I did something like this, it would more than likely be a "sidewinder" setup with the turbo moved to the passenger side of the engine bay.
With the dang log manifold I had to spent 20 minutes with an air hammer moving the firewall back. :mad:
 

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The quick spool valve for the most part is a band-aid for inefficiencies.

It has been shown that a 2.0L is capable of utilizing a single 88mm+ turbocharger. These applications of course are all out no expense spared race cars.

When you start to design a manifold or set up an application such as you have pictured you are closing off half of the turbine housing and creating a single nozzle effect by forcing all exhaust gas to flow through the single port. This can have ill effects on the system especially if the gate does not open.

I would recommend reconsidering the application or setup by looking at alternatives in your; Fuel type, Tune or even turbocharger choice.
 

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Discussion Starter #8
Build a proper twin scroll manifold for it, and use matching turbine housing.

And what are you doing for boost control etc ? That can make a good difference too.
I started on a twin scroll manifold but fitting it behind the motor is everything but impossible. Several different runner paths. Ended up even trying unequal length runners, and at best I was able to get the turbo to fit but no room for a downpipe.
Perhaps there's a reason there are ZERO delta platform twin scroll ecotec manifolds to my knowledge.
I still have the project on the shelf in case I can find a way to make it fit.

Boost control is a single pte 46mm gate and a Sirhc Labs Cortex ebc. I do have the DC at 100% during spool.

This controlled allows boost by gear/rpm which was a HUGE step up in drivability.
 

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Discussion Starter #9
The quick spool valve for the most part is a band-aid for inefficiencies.

It has been shown that a 2.0L is capable of utilizing a single 88mm+ turbocharger. These applications of course are all out no expense spared race cars.

When you start to design a manifold or set up an application such as you have pictured you are closing off half of the turbine housing and creating a single nozzle effect by forcing all exhaust gas to flow through the single port. This can have ill effects on the system especially if the gate does not open.

I would recommend reconsidering the application or setup by looking at alternatives in your; Fuel type, Tune or even turbocharger choice.
If a gate fails to open, you're up shit creek in a split second on ANY turbo setup.
What is the ill effect of cutting a .84ar to a ~.42 during spool? That's effectively the entire idea.

Also, if the turbo selection is wrong in your opinion, what would you suggest for 750hp on e85?
 

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i dont buy precisions thoughts on quick spool at all, thats essentially telling every OEM they are using the wrong turbos since diesels do it with VGT, hell during warm up on my old powerstroke i would hit 3 psi at idle with the factory turbo. The oems just do it directly in the turbine housing, people always want a wider power band, or at least the ability for it to tune for the fastest possible setup at every rpm point the engine will see.
 

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I started on a twin scroll manifold but fitting it behind the motor is everything but impossible. Several different runner paths. Ended up even trying unequal length runners, and at best I was able to get the turbo to fit but no room for a downpipe.
Perhaps there's a reason there are ZERO delta platform twin scroll ecotec manifolds to my knowledge.
I still have the project on the shelf in case I can find a way to make it fit.

Boost control is a single pte 46mm gate and a Sirhc Labs Cortex ebc. I do have the DC at 100% during spool.

This controlled allows boost by gear/rpm which was a HUGE step up in drivability.
There is more to boost control than just a gate, various control options, plumbing options, spring options etc. They can all make a difference ( albeit not huge unless you had it bad to start with )

If you're restricted with manifold design, then the spool valve will be a relatively easy and cheap option to try, of course you'll also need a new turbine housing too.

If a gate fails to open, you're up shit creek in a split second on ANY turbo setup.
No you arent. Any decent ecu will have good overboost protection so there would be zero risk.

And ideally you'd also take control of the spool valve's opening from the ecu too.


And if you arent using a good ecu....it's a good time to change.
 

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Obv' a twin scroll manifold is the best bet IF it was possible, and the difference it can make on a 4cyl is pretty insane, but by sounds of it, no hope on yours.

Your idea 100% works, and works better than a SP-style quickspool valve for sure. Should last better too. We know wastegates take the heat.

The other option, though needs more fab work, is a twin scroll flapper, which is smoother flow than a SP-style valve, but no better than a wastegate setup really.
My friend made one for his car and it works, and BorgWarner had a few turbos at SEMA with the setup built in. They were making out like they were gonna produce them, but no sign yet.



A few OEM applications over the years have done this instead of more conventional VGT vanes too.

It has been shown that a 2.0L is capable of utilizing a single 88mm+ turbocharger. These applications of course are all out no expense spared race cars.
Utilising isn't the same as spooling one at low rpm. You're not magically doing that without some external help no matter how little expense is spared.

When you start to design a manifold or set up an application such as you have pictured you are closing off half of the turbine housing and creating a single nozzle effect by forcing all exhaust gas to flow through the single port. This can have ill effects on the system especially if the gate does not open.
The ill-effects of it not opening is far less catastrophic than a wastegate doing the conventional job not opening, and no more likely.

I would recommend reconsidering the application or setup by looking at alternatives in your; Fuel type, Tune or even turbocharger choice.
162 in half a mile says his tune isn't far out, and fuel type won't massively affect spool?
 

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I didnt really look at the first pic....

TBH, using a wastegate for that, I dont think is a good idea. Most wastegates, the valve stem never seals 100% Normally where the gate vents externally this is of no concern, there is never any pressure on that side

With this proposal, you will be applying full pre-turbine pressure through the entire gate and some of this will end up in the lower chamber which in turn may reduce diaphragm life.

IMO the quick spool valves now do look like decent quality pieces and would require less fabrication to install ?

Or perhaps if you used a gate like Turbosmarts old Progates, these totally isolate the chamber section from the hot valve section.

https://www.pinnaclecorvette.com/Turbosmart_Pro_Gate_48MM_External_Wastegate_p/ts-fg-wgate-48.htm
 

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i will say this i ran this type of setup on my nissan 350z and picked up power about 800 rpms sooner on a 6766 with 1.32 divided when compared to a 6766 witth .96 open. peak power was pretty much the same but everywhere under the curve picked up to varying degrees and i simply ran a 15 psi spring in the second volute wastegate didnt try to tune it at all.
 

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Discussion Starter #15 (Edited)
Overall it's looking like a remote mount sidewinder setup with a t3 hot side is going to be my best bet in terms of cost/time/reliability. T3 will obviously flow less up top, but running remote frees up a ton of room for a properly designed 4-1 collector, which should help flow greatly vs the current log manifold.
Changing turbos does not interest me, since
A: I can get a 0.63 or 0.82 t3 housing for this one for $200
B: any other turbo that pushes ~75 lb/min is going to respond similar anyway.
C: I'm what one might call a Borg Warner fanboy (sorry pte ;) I do love your gates though)

Regardless of why I end up doing I will be adding an ebp gauge to the current setup along with egt so that I can make a useful comparison, not just a spool difference.

The current idea is something like this:



But flipped 180* so that the v-band outlet is facing up, and run a 2.5" pipe to the turbo. Everything ceramic coated and heat wrapped should keep velocity loss to a minimum.


Just to be clear this was not at all a "this is what I'm doing so validate my opinion" thread. Just curious since I hadn't seen it done before.



StavX81: Yes I would like to think the tune is pretty solid... I am a tuner but really only do gm delta platform cars. Not a huge market, but enough to fund my hobby lol. FYI, due to machine shop delays, this was done on a bone stock 90k mile long block aside from valve springs and cams. Based on the logs it was putting down ~550-570whp on the 162mph run. The stock head bolts weren't happy; head was lifting enough that there were signs of coolant on the plugs but no other issues.
Well, other than a lifter/lash adjuster exploding on the last run and taking a rocker out with it. Had to have happened right as I crossed the traps because it never missed a beat the entire run.
 

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Do it. I did it with a Ebay 60mm wastegate on a S400 and picked up 500-800rpm of spool time. I could get to 10# cruising highway brake boosting at 2200rpm. I got rid of the setup purely because of traction issues which made it pointless. Without on the same road I wouldn't hit 10# until 28-3200.
 

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i dont buy precisions thoughts on quick spool at all, thats essentially telling every OEM they are using the wrong turbos since diesels do it with VGT, hell during warm up on my old powerstroke i would hit 3 psi at idle with the factory turbo. The oems just do it directly in the turbine housing, people always want a wider power band, or at least the ability for it to tune for the fastest possible setup at every rpm point the engine will see.
This is not claiming OEM or VGT is incorrect at all.

The veins are designed to direct equalized pressure around the turbine housing and wheel. When you block off a single port on a divided turbine housing you can cause in-equal frequency and aggressive pulsation on one side of the turbine wheel.
 

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It has been shown that a 2.0L is capable of utilizing a single 88mm+ turbocharger. These applications of course are all out no expense spared race cars.
What does this shitty anecdote have to do with his engine and turbo combo?

Obviously if you have a clutch guy and Liberty you can make a pass staying in a very small portion of the power band. Which is nothing like what he asked.
 

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What does this shitty anecdote have to do with his engine and turbo combo?

Obviously if you have a clutch guy and Liberty you can make a pass staying in a very small portion of the power band. Which is nothing like what he asked.
When taken out of context it does not have the same delivery as intended. The whole premise of the statement is to make note that with the proper setup small displacement engines can utilize a rather larger single turbocharger. This was intended only for educational purposes as it is unknown what the OP's knowledge is.

I agree with the other statements mentioning that the OP needs to try and fabricate a true T4 divided manifold, but OP has stated that he is working with space constraints.

In terms of different tunes and fuel, it was not know what the OP was using so the suggestion of going to E85 or Alcohol could be made to help increase exhaust gas and better aid the characteristics of his turbocharger. The type of fuel was not known when the post was made.
 

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Discussion Starter #20
When taken out of context it does not have the same delivery as intended. The whole premise of the statement is to make note that with the proper setup small displacement engines can utilize a rather larger single turbocharger. This was intended only for educational purposes as it is unknown what the OP's knowledge is.

I agree with the other statements mentioning that the OP needs to try and fabricate a true T4 divided manifold, but OP has stated that he is working with space constraints.

In terms of different tunes and fuel, it was not know what the OP was using so the suggestion of going to E85 or Alcohol could be made to help increase exhaust gas and better aid the characteristics of his turbocharger. The type of fuel was not known when the post was made.
I appreciate the professional response. I would like to think I am pretty well educated but there's ALWAYS more to learn. Your comment about unequal drive pressure on the turbine was something I had not thought of, but makes sense.

I understand that very very large turbos can be utilized, especially with an agressive launch control/antilag and/or an auto trans with a high stall. It just becomes a lot more difficult to get that utility from a roll or soft launch. No one makes built manual transmissions for these cars that are much better than stock. I actually run a base model trans due to better gearing for 1/2 mile and, most importantly, they're $300-$500 a pop at the scrapyard. That said I'd much prefer to not intentionally push it to the edge off the line.

Yes I am on e85, and have ignite practically next door, if I want some extra security on high boost track days.

Due to the space constraints, a true divided t4 setup simply does not seem possible. My only hope would be moving the engine and trans forward, which would then cause a whole host of other issues to work around.


What it's really boiling down to is if I don't want to rely on nitrous (sometimes you don't get much notice for those theoretical highway runs), my best bet is probably switching to a t3 housing. It should still be capable of making the desired 650-750 depending how brave I'm feeling, and have much better response.


It just so happens I have a close friend with a nearly identical setup (same engine, s362FMW vs my s362sx-E) who is in the process of switching to a t3 0.63 right now. His car should be up and running by tomorrow evening. Previously he was running a divided T4 0.84 housing on an open log manifold. Whatever gains he sees should be even that much better for me if I make the switch, since I'm currently on a T4 0.88 open housing.
 
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