V8KILR

A bigger turbine on the Jspec (as they used the lighter ceramic turbine wheel), but they have a smaller compressor, so slightly lower hp capable.

Mathematically, the equivalent sizes for a single turbo would be: JDM spec: Twins: Compressor: 37/62 Turbine: 48/60 Equivalent Single: Compressor 52.3/87.7 Turbine 67.9/84.9 UK Spec: Twins: Compressor 39/58 Turbine 44/52 Equivalent Single: Compressor 55.1/82.0 Turbine 62.2/73.5 Based on the calcs above, a 52mm to 55mm turbo should be fine.

It's a bit heavier than the Getrag's 51kg and is closer to 60kg without the converter depending on how much fluid is still in it. http://www.supraforums.com/forum/showthread.php?178650-Auto-Trans-Weight&p=1741415&viewfull=1#post1741415

The three flat lines at the bottom around 14V show what voltage they ran three of the pumps (044, 255 and 416) at to get those flow figures.

The Walbro 416 (aka 400, aka 485) is good for over 600whp when using E85 (800+ whp on pump gas), so none of you guys were running out of pump flow. Perhaps the lines, filters or injectors were the flow limiting issue? e.g. http://www.supraforums.com/forum/showthread.php?686598-Single-Walbro-Dyno-679whp-E-85

Whatever kit you get, make sure it has good built in safe guards (to reduce boost and/or timing) so that if anything fails or you run out of meth, you don't blow your motor.

I've decided to pull the TH400 out and put my Getrag V161 back in the car. Testing on the street with the compound setup, it still doesn't launch as hard as I want it to with the auto and nowhere near as hard as it used to launch when I was manual. Unfortunately this means the compound setup is coming out. Despite showing great promise for spool, the rear down pipe doesn't leave any room for the clutch master cylinder where it bolts to the firewall. I'll be going back to a small single turbo setup (probably a MasterPower 6564) bolting on to the SPA manifold (to keep it simple), and with E85 it should still make pretty good power. With the Precision 6870 showing such good results, I may look at running that turbo later on if it can clear the strut tower when bolted to the SPA manifold. There were still some issues with the compound setup with oil drain leaks and the big issue was that the thin wall stainless pipes were getting red hot with just one dyno run and the associated heat issues that can cause. Both are fixable, but not easily so and made harder by needing to allow for the clutch master cylinder.

I've done a few changes to the setup and here's what it looks like now. As you can see I've changed it to a compound setup as the racing season is starting here soon and I think that's the quickest way for me to get the spool and power results I'm after. I haven't given up on the sequential and I still have all the unaltered parts for it, so I'll look at it again next winter. I took it to the dyno today and it was looking promising until I started blowing off the boost hose to the QSV and the vacuum hose to the power steering. They both blew off twice and with the QSV not opening, the back pressure sky rockets, so I gave up on tuning for the day until I can stop these hoses blowing off. I got up to 35 psi during testing and 370rwkw at part throttle on one run. Here is one of the early dyno runs (with both wastegates running off spring pressure) showing how much quicker the boost comes in compared to the single turbo setup I had. Increasing back pressure at higher rpm causes the boost to drop when running off the WG springs only. Later runs allow steady boost when under ECU control. As you can see, it reaches the same boost level almost 40 km/h earlier than the single 69mm turbo did. That run had the big turbo at 15 psi (PR = 2.0) and the small one adding 14 psi (PR = 1.5) for a total of 29 psi boost. This is quicker spool than the sequential setup as well and shows the advantage of compounding the boost and not having to wait for the second turbo to come on line. I have noted that the torque flat lines from 80-120 km/h though and I'm thinking that is probably my torque converter not holding at that rpm? I have a stronger one in the garage that I may need to swap to.

The good news is that the reverse flow out the #2 turbo intake was resolved by using #1 turbo pressure to the controlling #3 and #4 wastegates instead of manifold vacuum. Also the Hobbs switch on the two controlling wastegates works correctly and closes one compressor wastegate and opens the other one exactly as planned, so the transition to the #2 turbo is controllable by #2 boost pressure and works as planned. Unfortunately, there is now another issue and that is surging from the #2 turbo after it is online. The reason it didn't surge last time is that it was leaking boost through the #3 wastegate which doesn't happen now. I tried transitioning the turbo between 10 and 20 psi and from 4800rpm to 5800rpm, but it didn't seem to make much difference. There are two possible reasons for the surge that I can think of: 1. The #2 turbo is spinning too slowly and doesn't have enough drive pressure to maintain flow at the set boost pressure. In other words, it's trying to run to the left of the surge line on the compressor map. 2. The engine cannot consume all the airflow from both the #1 and #2 turbo at the set boost pressure and the #2 turbo surges first as it's the bigger turbo. I'm not sure which one (or both) of these reasons is the cause of the issue? There are a few possible fixes I can think of. I'm not very keen on options 1 or 2 as the #1 turbo doesn't flow enough air (so doesn't make enough power) on it's own at just 20 psi boost. 1. Have a controlled boost leak from the #2 turbo up to the point where it can be fully bought online, perhaps around 7000 rpm? 2. Drop the spring pressure in the #2 turbo wastegate to 10 psi so it can be controlled by the ECU to leak exhaust gas up to the point where it can be fully bought online, perhaps around 7000 rpm? This may not work anyway as there may not be enough drive pressure. Probably would need to work in combo with option 1. 3. Reduce the size of the #2 turbo to be closer to the #1 turbo. Currently they are 5459 and 7677 respectively. A 61-67mm rear turbo may have a surge line sufficiently far to the left of the map to not surge when brought online. That means the turbine side would be much smaller as well which may not bode well for back pressure. MasterPower do make a 6168 with a 1.22 divided housing, a 6568 with a 1.22 divided housing and a 6777 with a 1.05 (turbine size I'm using now) or 1.22 divided housing. One of these might turbos work better to eliminate the surge issue if they spin up a lot quicker? 4. Change the setup from sequential to compound (which will be pretty easy to do) and run 45 psi boost which is 1 bar boost from each turbo. This should work okay as the turbo sizes are already setup to what should be a reasonable combination for compound turbos.

Here's how the Hobbs has been wired up. Dyno booked again for next Monday.

I've come up with an even simpler and better method to control the two compressor side wastegates. It only requires one Hobbs switch set to close the flow at 15 psi and when I increase the spring rate on the #4 wastegate, it is very likely that the check valve in the diagram is not needed at all. Using this method it forces the #3 wastegate to close and the #4 wastegate to open at exactly the same time, when #2 turbo boost hits 15 psi. It also eliminates any issues from pressure on the valves faces by forcing the wastegates open and closed.

Thanks. Unfortunately I don't have any free outputs on my ECU which limits my options a bit. Thanks to some suggestions by dazzadude (from Aussie) on the USA forum, here's what I think will make my setup work correctly. Hobbs_2 opens at 1 psi boost to stop the #4 wastegate opening under vacuum. Once it's at 1 psi boost it then will function based solely on the pressures to the top and bottom ports. The pressure to the Hobbs_2 comes from the manifold. Hobbs_1 shuts off the flow to the bottom of the #3 wastegate at 15 psi boost. This will force the wastegate closed and merge the flow from the #2 turbo. The pressure to the Hobbs_1 comes from the #2 turbo so that it running fast enough to not surge.

Here are some pics of the current setup.

OK, I've finished on the dyno for today, so here's an update. This is a diagram of the system I had built by Ronnie Lim at RSL Automotive in Auckland. The two turbos I'm using are a MasterPower R545 (5459) 1.00 AR rated at 600bhp for the #1 turbo and a MasterPower R7677 (7677) 1.05 AR rated at 1000bhp for the #2 turbo. As this system works on the exhaust side just like a compound setup does, I decided that compound sized turbos should work best for my sequential system. I had several issues on the dyno today, one of which was boost leaking from one of the #2 turbo pipes where it joins the #4 wastegate, but I managed to fix that. One issue I didn't manage to fix today is that the #3 wastegate does not close when the #2 turbo boost pressure matches the #1 turbo, like I thought it would. Instead of closing nicely, it fluctuates between wanting to close and wanting to open. The only thing I can put this down to is that the #4 wastegate is fighting against it closing. One of my earlier designs had a swing check valve instead of the #4 wastegate, and that may be the solution to this issue? The #3 wastegate not closing results in a massive boost leak from the #2 turbo, hence power and boost does not go up much once the #2 turbo kicks in. Unfortunately the spool of the 54mm turbo doesn't seem to be any better than my old 69mm turbo at low boost and at around 8psi boost, the old turbo leaps ahead. This is the most important issue I need to resolve, as getting more power down low was the main reason for me doing this setup. Getting less back pressure down low is probably the key to this. Here is a dyno comparision between one of the runs today (280 rwkw run) and one of my old runs (480rwkw run). You can see the #2 turbo adding boost at 14.5 psi and 137 kmh. The back pressure was much as expected. On that 280rwkw run it was 37 psi back pressure with 18 psi boost, so was around 2:1. As the boost should have been much higher if the #3 wastegate had closed, it will probably end up around 1.5:1 once that issue is sorted. When the boost is turned up even further, it will go higher of course. Most of the back pressure is a result of the #1 turbo and turning the boost up on the #1 turbo does push the back pressure even higher. Overall, not as good a result as I had hoped as I have two major issues to try and resolve.

The dyno is booked for Monday 11th August. I'll take a video on the day as well.

I have finally got an electrical issue I was having fixed so I took the Supra to the trans guy today to check the flex plate. The flex plate was the cause of the rattling noise. The bolts they used were a bit long and were bottoming out, so even though they were tight, they were not holding it properly. My trans guy took all the bolts out and shortened them by 2mm and problem solved. I can now finally book the Supra to get it dyno'd. I'll update this thread when I have a booking.

Progress is a bit slow at the moment. Got a engineering company (not my fabricator) to add some ports to the intercooler pipes and that took them 7 working days to get round to it. I put the pipes back on last night, so all the hoses to the controlling wastegates are all hooked up now. I have booked a time with my trans guy on Monday to check the flex plate, as I think its causing the rattle I can hear. Once that's sorted, I can then book some dyno time.

I've read that too, but if that was loose, wouldn't it be running badly due to incorrect timing?

Thanks. I checked the crank bolt and that's fine. I also had that happen to me 5 years ago. That made more of a ticking sound (due to fretting on the crank key) where as this one is a rattle sound. The turbo pipes are tight but don't touch each other, and I had the problem before I dropped the car off for the turbo setup so that's not the issue either. I've done some more reading on flex plates with loose bolts or cracked flex plates and it seems very similar to my issue. I'm going to drop in and see my auto trans guy next week and put it up on the hoist while its running to track the sound down.

Got my Supra back from the fabricators today. It's only seen a few psi so far, but feels quicker on the street as you would expect as the first turbo is now a lot smaller then my old single turbo. It will still need tuning before I know how much quicker it really is. Also none of the wastegates or the QSV have boost hoses to them yet, so I'll connect them all up this weekend. There is one little issue I need to solve before dynoing it and that is a rattle/knock that I first noticed about 6-8 weeks ago. I thought it was the exhaust rattling at first as it louder when cold and goes away as the rpm increases and gets quieter as it warms up. On checking with a stethoscope, the front idler pulley is very noisy so I'll replace that but so is the area around the trans bell housing. Could it be the flex plate?

It's all apart again for final assembly, so here's a better pic of the exhaust pipes and waste-gates.

Sure is. My fabricator is doing a very good job squeezing it all in there.

Inter-cooler plumbing and controlling wastegates all plumbed up.

Yes there is, but I want to wait until its all finished before I post pics of the whole engine bay.

Getting close now. Should be finished mid next week.