V8KILR

Thanks for the link. It was a good read. Believe it or not, the BMW setup is EXACTLY the same as the Boost Logic compound system ended up (on the compressor side) in its final form. During testing Boost Logic found that the #1 turbo (~50mm) was causing too much back pressure at high boost from the #2 turbo, so they introduced a bypass from the #2 turbo at high boost directly to the intercooler to solve that issue.

That is not what I call a well designed sequential system. Check out this link.http://www.supraforums.com/forum/showthread.php?512779-Another-SP-Sequential-Build And here is why. The log manifold in that design results in poor flow during the spool up phase which is why their setup doesn't spool that quickly. It also had back pressure problems with the #1 turbo and a huge dip in the torque curve during the transition when the #2 turbo comes on line.

A 60mm was big enough for the Boost Logic compound system but I may need more flow then they did. If so, two 50mm or 60mm wastegates could be used if I can squeeze them in there. I have thought of doing something like this with a big pipe joining the two manifolds at the same place the wastegate pipe would fit. It would work very well, but I think my setup will out spool a standard sequential design. E.g. Boost Logic got 20psi by 2800rpm from their compound setup.

That's the Boost Logic system. It has some similarities with how mine works on the exhaust side, but it uses different size turbos and controls the wastegates differently.

I will definitely be doing this as I'm pretty sure it will work and testing will tell how well. My unique divided manifold quick spool valve is working very nicely and everyone (in the USA) thinks it can't be done. LOL. I'm not familiar with their system, but I'll Google it. The one I'm most familiar with is the Boost Logic design.

Yes it does. Its a 60mm wastegate which should do the trick.

Thanks. The #1 wastegate prior to the #1 turbo is to bypass all unneeded exhaust gas around the #1 turbo, so minimizing back pressure in the manifold and #1 turbine. It has crossed my mind that I may need to bypass more exhaust flow then one 60mm wastegate can handle, and if so I'll try and squeeze in another wastegate there as well, perhaps one on each side of the manifold. As you say heat is definitely an issue with so many pipes and turbos. To try and counter this, I will be wrapping the manifold, both the down pipes and both wastegate pipes to try and minimize the engine bay heat.

I've been thinking of doing a sequential turbo setup for a while now as a means of getting more boost at lower rpm, so that I can run a lower stall in my TH400 converter. A lower stall will allow me to have a converter that holds more power and has less converter slippage, which results in more power to the rear wheels. Having looked at every compound, sequential, and twin turbo setup that I could find on the internet, there wasn't one of them that I was happy to install in my own car due to various fitment, cost and complexity reasons. Therefore I decided to design my own sequential turbo system. They say a picture is worth a thousand words, so here's a diagram of how it works. This sequential setup is basically a compound turbo setup on the exhaust side (but with identical size turbos) and a sequential setup on the intake side. This means you get all the advantages of a compound turbo setup for spooling the turbos, but with none of the disadvantages of the compound setup such as the boost being too high for a gas engine. Also both turbos are exactly the same size, so you don't get any issues with different size turbos fighting each other in the sequential setup and having the large one potentially overpowering the smaller one. By spooling the second turbo with the gas exiting from the first turbo, the second turbo will spool much quicker then if it was just receiving some exhaust gas diverted from the first turbo, as most other sequential turbo systems do. This means that instead of having a big dip in the torque curve when the second turbo comes on-line, there should be little to no dip in the torque, resulting in a torque curve more like a large single turbo. This setup is super simple and only requires 3 devices to be controlled, which is simpler then any other sequential turbo setup I've seen. There are two wastegates, one used for each turbo and they are set to exactly the same boost level. These wastegates need to be controlled separately as the two turbos will require different duty cycles on the wastegate to maintain the same boost level. This can be done via two boost controllers or via one boost controller and one aftermarket ECU. There is also one combined reed/air intake valve (with an attached actuator) required that needs be opened when the second turbos boost catches up to the first turbos boost pressure. This could either be done using a Hobbs switch set to the same pressure as both wastegates are or by an aftermarket ECU controlling the flow of boost pressure to the air intake valve's actuator. My design uses a proper high flowing manifold to the first turbo, eliminating the ugly and often poor flowing log manifold seen in many sequential designs. Here's a drawing I did to show how my sequential setup will be implemented in practice on my 2JZ-GTE Supra engine. My design uses a 3.5" down pipe between the #1 and #2 turbo, a 4.0" down pipe for the #2 turbo and the 60mm wastegates have 3.0" pipes to maximize the flow. This is the 2JZ-GTE intake air control valve I will be using. The curved section will be removed to make it straight through. I am planning on changing my single turbo 2JZ-GTE Supra to this setup over the next winter season and I will update my website with the results from this setup then. My setup will use two Turbonetics 60mm wastegates, the Supra OEM reed/air intake control valve (50mm) and two MasterPower race series R6164 (61mm) turbos. These turbos are good for 700hp each on gas when run around 30-35psi boost, making for a potential of 1400hp from both turbos on gas or 1500+ hp when using E85. I use E85 and my goal is 1000whp through the TH400 gearbox which is around 1300hp. This will hopefully be achievable with around 35psi boost. As this is a different design to what anyone else has done, its possible that it may require some tweaking to work correctly. After discussing this design with a friend, there are two areas that I think may cause issues. One is that the 60mm wastegate from the #1 turbo may not allow enough exhaust flow around the #1 turbo resulting in excessive back pressure or over boosting. The other is that the #2 turbo may cause too much back pressure in the #1 turbo's down pipe, which will reduce how quickly the #1 turbo spools. Both these issues can be resolved with some design changes if they do occur. All constructive comments and suggestions are welcome.

Is the Supra loom you got for the TT auto or a manual TT? If its a manual there's your problem.

Thanks, it's great to see someone else doing their own QSV setup. Do you have any pics? The side of the manifold that gets blocked off by the QSV can balance pressure with the other side through my wastegate pipe if the 20mm gap is too restrictive. Based on that I'm fairly sure the pressure on each side will be close to even. This pic shows how easily the exhaust gas can flow from one side to the other.

I'll be giving it a good testing this coming summer in NZ with lots of drag racing and road trips. The downpipe is wrapped and the actuator is a genuine Garrett item with their high temp diaphram in it so hopefully it will be okay. If it fails, I do have a spare actuator and I'll get a heat shield made for it if the first one fails.

The Getrag 233 (V160) is rated to 490NM by Getrag which is 361ft/lb. Absolutely amazing what punishment they can take considering their official torque rating.

Sorry I missed your post at the time. The dyno graph shows a power reduction but I believe that is all due to the converter change. Shame I didn't get a dyno graph before changing the converter. I think that as long as the wastegate is still bleeding off some exhaust gas at full power then there should be more then enough exhaust gas to spin the turbo as fast as it is needed, so supplying the same amount of air to the engine. Also if the wastegate is not 100% open at full power, then there should be enough exhaust flow out the wastegate to stop any exhaust restriction occurring. I run a 60mm wastegate. My tuner says he didn't change the wastegate settings at all and its holding exactly the same boost psi as before, so in conclusion I don't think the restriction caused by the valve is having any detrimental effect on the power. I'm using a 0.84 AR exhaust housing (both before and after the QSV install) and I have a 1.00 AR housing that I can swap to if I feel it will help in the future. As power keeps climbing all the way to the 8500rpm redline, I think its all good at the moment.

Thanks. The final version looks like this:

The converter I changed to slips about 9% more (based on max 230kmh vs 250kmh before at same rpm) which results in the lower hp once you get to full boost. A QSV will only make more power until max boost is reached (110-115kmh without QSV) which this one does. This would be around 5000rpm with my setup so the mid range is way better. My QSV starts opening at 5-6psi and is fully open at 11psi as it is just running off the spring pressure. There are probably more mid range gains to be made by holding it closed for longer. When driving around town, it now gets on boost extremely quickly with just a small push on the throttle which makes it really responsive and great for overtaking. It has exceeded my expectations on how well it works. The best part is that I didn't need to cut up my 6Boost divided manifold like you have to do for some of the other QSV designs. This design would work equally well with either a divided or an open manifold.

And here is a dyno graph with the QSV line being the red one. This dyno is for the 3000rpm converter which unfortunately slips more then the 2600rpm converter, resulting in the lower power line.

I finally got it tuned and the QSV is working perfectly. Just before the tune I threw a new set of plugs in it and it didn't misfire at all on the dyno when he first tried it, so all this time it was plugs causing my misfire. Strange how it was okay with the QSV open, but I guess the cylinder pressures were lower. So I can finally report that my divided manifold QSV is working perfectly! Yah!

I have changed the shaft material to Nitronic 60 S/S which theoretically should not bind (gall) with the flange S/S (302 or 316). It now also has a bit more clearance which will help as well. I have also had the QSV modified so that the shaft is now 1/3rd of the distance from the lower leading edge of the flap. This moves the shaft to the center of pressure on the flap so that it can open more easily. The actuator is still the same one I have used all along. With my wife taking a video of the QSV, I have brake boosted the car in the garage to check how easily it opens. I can report that it now opens smoothly and evenly when the boost rises from 5 psi (when it cracks open) up to 10 psi when it is fully open. This is a big improvement on how it was with the shaft in the center of the flap where it was very jerky and slow to open, so problem #1 solved. Unfortunately when testing it on the road it still sputters at around 8-9 psi. I'm starting to think this may be a tuning issue, so I'm changing the converter to a higher stall one next week (that can still hold the power) and I will then take it to my tuner to get it fully tuned with the QSV. I'll update this thread once that's done.

If you go to the bottom of this page: http://mkiv.supras.org.nz/specs.htm there are all the weights by model and option.

I have twin Walbro WSP330 pumps with twin factory lines to each end of the fuel rail and my Link G4 ecu turns on the second pump at 15 psi. Probably simpler to do a Y fitting for both pumps at the hanger end and another Y fitting to split the feed each end of the rail as well. Most modern fuel pumps have a one-way valve built in (mine do), so it depends what fuel pumps you are getting. Bosch 044 might not, but they sell a one-way fitting that screws on the end.

Yep. If the tires will hold the launch, that's exactly how to do it. You can do the same without the line lock by just left foot braking.

+1 on the high stall. The only other options are NOS or a QSV (if TT) for getting a faster launch.

I been thinking about the boost issues I'm having and am wondering if part of the problem is compressor surge? The turbo does spool up a lot sooner and maybe the engine can't use the boost quick enough at that rpm. The old style T70 compressor wheel does have a fairly high surge line, assuming its the same as the Turbonetics T70.

Looks like if you raised the rev limit, it would make a lot more power as well.

The anti-seize paste did the trick but it is opening too slowly. To speed up the opening, I have installed a line direct from the turbo to the QSV so its getting boost pressure as fast as possible now. On a test today it is stumbling around 9psi boost so it is choking even earlier then I thought it was before. Theoretically the QSV should be nearly open by 9 psi as it starts opening at 5psi and is fully opens by 11psi in testing with the engine running when I open the actuator with my hand pump. To see if this happens when boosting, I did a brake boost stall test in the driveway and the QSV is not moving at all until 9psi and then it suddenly opens, but just a little too late to stop it choking. I think the reason that this is happening is that I machined one side of the flap down so as to not hit the center divider on the turbo and I probably took 1mm off the width on that side. This means the flap is now off center so it is taking more pressure to open the flap then if it was perfectly on center. At 9psi boost there would be a lot of force from the exhaust gas on to the flap, so what I should have done is take 1mm off the center divider on the turbo instead and then it would be much easier for the actuator to open at the 5psi the actuator tries to starts opening at. I'll pull the QSV off and get another flap made and this time machine the turbo housing to clear the flap, not the other way round. The only other option would be to have a high pressure boost source (say 30-40psi) to use to open the actuator, but that sounds too complicated. If its still an issue after installing a new on-center flap, then I'll put the original MasterPower 1.00 AR turbine housing on which will move the choke point higher up the boost range.