wantboost

iTrader: (2)

That's not what a sequential turbo setup is

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wantboost

iTrader: (2)

What has been done to the motor/trans?
What size turbos are you using?
What sort of drive pressure (backpressure) do you see before the first turbo?
What pressure ratio is the atmospheric turbo running (the one that has a filter) and what is your overall pressure ratio at the intake manifold?

What is spool/response like?
Power/torque? any dyno graphs

sorry for all of the questions but you're the first person I've seen with a functional, running compound setup on our small displacement motors which has me curious...
I would imagine it makes a great deal of torque, much more so than a single turbo setup

GrindTimeAuto

Whoa! Thats alot of questions. It's simple I get bored and start putting turbos on anything I can.This is my daily driver I have no idea what the hp/tq numbers are.I keep both turbos at 6psi for a total of 12psi. T3 & T3/T4
The only downside is its complex and annoying as hell to work on.Getting to something requires alot disassembly since.I'm always adjusting and changing stuff around.
Its very quiet the only thing you can here is the BOV. if I have filter removed I can hear turbos
The highest air temp at throttle body was 70F but its cold out here right now
I will have to tap the piping to get a drive pressure reading
Everything is stock my idea was to see if everything works(IT WORKS Then start building it up
I'll have it on a dyno soon

wantboost

iTrader: (2)

at 6 psi it would be hard to actually hear the turbo...

hows it drive on the street?

I'd be curious to see a pressure gauge on each compressor outlet to see when they start to make pressure/compound the other

GrindTimeAuto

I had turbos at 3psi that were screaming but that was a remote setup so the spool sound was loud
Great street manners feel completely normal idle's the same.I try to keep it out of boost for daily driving.
Hopefully I'll have some answers for you soon,I need to get a gopro or have somebody hold the camera while I'm driving it

Balor_Gr

Another question.Do you use the small turbo wastegate gases in a closed loop style to help the big spool?
Also ALL the setups i saw were staying with the "rule" that the small turbo runs higher pressure.Anyway keep up the good job!
IM DYING TO SEE THE DYNO SHEET
Compound setup idea was eating my brain.I tried a lot to forget about it...

92cxyd

Yeah try twincharging it can be fun to sort out too, I have much experience with my setup.

Also watch F1 next year compound boost 1.6l w/ energy recovery

OH and for twin turboing a 1.8l, I remember this from RHMT

GrindTimeAuto

NICE!!!!!!

GrindTimeAuto

Small wastegate dumps into turbo exhaust inlet for large turbo to help spool it faster.Large turbo will spool a little later without help from the small turbo wastegate.

crxtc_vtec

iTrader: (2)

I'd like to see vids as well! This is quite intriguing!

turbohatch96y7

iTrader: (15)

Where's theshodan and all the haters at???

Nice job gta I need a dyno sheet now!!!

Tony the Tiger

I did a sequential setup several years ago with my Integra, and took parts off a MKIV Supra TT to make it work. I had twin GT2860R turbos with a custom manifold, a cross over balancer pipe between the two turbos, along with all the actuators, butterflies, etc... I used the air control valve and reed valve to block the 2nd turbo compressor, and used the Supra EGCV and a vacuum tank to control the butterfly for the exhaust exit. The solenoids were controlled by AEM EMS, and had pretty good control under most conditions.

Unfortunately, the setup only looked pretty good on the dyno during a steady run. In between RPM points, or driving conditions besides full acceleration, the 2nd turbo had trouble maintaining speed and there is always a flat spot in the powerband. Stabbing the throttle at mid RPM's did not fully take advantage of the sequential operation and still had a delay no matter how I tweaked it.

It did manage to make about 200 WTQ @ 3000RPM, and the driveability part feels like a single small GT28R around town. Overall, it didn't drive well during spirited driving or circuit conditions though, and was only good for cruising around down, or all out drag pass. The setup made best power of 500 WHP.

If anyone is interested, I can post some pics and videos of it.

92cxyd

^^^^ Yes please Post pict and vids, always in for boost pr0n

Tony the Tiger

Some pics of the setup (Twin GT2860R 0.64 A/R T25
2.5" downpipes):





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.

Here's what it sounds and drives like:

wantboost

iTrader: (2)

tony always amazes me lol. I wonder how it would have performed in parallel as opposed to sequential.

and didn't that rhmt setup end up never being used or being really laggy and make **** power?

I've thought about taking two of my numerous z32 turbos (I would use the ones that have a stock clipped turbine wheel (.63ar manual housings) and an upgraded t28 compressor wheel in stock comp housings) and making a parallel twin setup. maybe on a stock ls block/bottom end with a mildly ported head, some sort of upgraded cams, better intake mani, etc. and seeing just what the results would be

the stock turbine side would be more than capable of making mid and top end power (especially with the clipped turbine wheel, its somewhere between a 10-20 degree clip) while not being laggy. the t28 (basically the same wheel as a 60 trim t3 and gt2860) wheel would be more than adequate for mild power levels.

especially with a short runner manifold that's either coated or wrapped and turbine housings that are coated or have blankets.

maybe one day when I pick up a cheap 92-95 shell. I like the 96-00 better but that system, even with the wastegates unhooked from the flappers would still build boost and make emissions on a stock ecu a nightmare.

unless I went ghetto during emissions time and used and FMU/missing link so that if the system built 0-5psi I could still drive the car enough to pass the readiness checks without having to reset the ecu and start over everytime the stock ecu senses positive pressure.

Tony the Tiger

^^

When the motor becomes too small, the choice of turbos would become very rare and probably not available off the shelf.

A 1.8L or 2.0L, would be a split of having each turbo properly matched with a 0.9-1.0L motor.

If you were to put 300ZX turbos in it, the turbine side is already too much for the HP goal of 300 WHP range. It would require turbos with really small turbine wheels and big compressors, and the advantages of efficiency will quickly diminish due to these small sizes.

It is the same deal when sizing twin turbos for Skylines, like RB26DETT or smaller V-engines. Why these motors love turbos with huge compressor in relation to turbine (GT2871R, GT3082R, etc..) it is the same reason.

If you were to think about twin turbo, your goals must be higher so that conventional turbos in clean packaging can be used, like twin GT2560R's for 600WHP goals. In parallel twin conguration with clean routing of downpipes, etc.. it should ideally out-spool most single units within that power level, and much more "kick" in the low RPM's before boost begins to fully build.

Due to the twin GT2860R's I had, it already flowed too much on the turbine. When I was running in parallel, it spooled late, somewhere in the 6000RPM range. According to turbine flow, the twin GT28's has nearly the same turbine flow as a GT42R. It was an experimental setup, and these twin GT28's were handed down from my earlier Camry TT project.

wantboost

iTrader: (2)

the stock z32 turbos use tb02 turbine sides, which have a smaller wheel than standard t25 units. plus smaller ar compressor housings.

the turbine side is already restrictive on "bpu" z32s. that's only 1.5l per turbo, so a b18b or b20b might just be enough where it didn't suck

if you combined that with small hotside piping (outlets are 1.5" at best) into a single 2-1 intercooler core with a 2.5" coldside and it might be doable

GrindTimeAuto

Hey wantboost I added another boost gauge to see the pressure out of the large turbo.It definitely builds pressure at the inlet of the small turbo

92cxyd

I'll be doing the same with two boost gauges in the next couple of months on my Twincharge Civic.

GrindTimeAuto

Nice!!!!!Work on the twincharge civic!!!!!!

wantboost

iTrader: (2)

how much pressure and how soon? you aren't truly getting the benefit of a compound setup at such low pressure. you need to be running a minimum of 10psi, you'll really see how each turbo will truly behave at that pressure point.

really you need to be in the mid to low 20psi range to make the setup really work.. maybe higher if the motor can take it.

I had a small v6 turbo diesel in a box truck that had a small compound setup (similar turbo sizes) it was only running 10psi and it was boring at best. blocked off the wastegate and suddenly 38-40psi later I had a truck that would pass sports cars lol

try higher boost, you'll thank me later lol

GrindTimeAuto

This is the temporary setup until I get another gauge pod.
What I noticed is highway cruising at 55mph 5gear the low pressure turbo is applying at least 1psi.the high pressure turbo isn't applying boost until you give it more gas

92cxyd

^^^ keep in mind you see boost when the system is under a load, light cruise speed =low load.

I like going up mountain pass in 5th and turning the s/c and then fly up the mountain seeing 20psi+

GrindTimeAuto

Cleaned up my gauge setup

F22Master

Which boost gauge is which?