Topic: Twincharged Solstice = Turbocharger + Supercharger

[Critterman]

Actually Elff it is quite easy to do if you are speedshifting.

[Steelmesh]

I was just doing some data mining comparing the turbo-only drag data and I found out that I am totally wrong in my previous post about my money-shift experience.  I am quite upset with myself for making a confident post that turned out to be wrong (Dunning-Kruger fail moment), I am mistaken and will try again. 

You have to be an idiot to shift from 3rd to 2nd.
No excuses, you are a ing idiot and don't know how to drive.

Elff, I accept this fact
 

Omg!  That is crazy!!!!!

Matt, I was mistaken about the 2-3 money shift explanation as it was actually 3-4, that explanation post which you responded to 'with surprise' is incorrect and I would like to provide accurate data to recover from my folly.

Here is the money shift log.  At the top of 3rd gear I hit 102 mph, you can see I have the cursor at the beginning of the over-rev, it pulls the tires down to 78 mph and I see the 2nd gear at 7,475 rpm is 68 mph in this same data recording.  One thing is for certain the engine is alive after multiple dyno pulls and now the twincharger setup.

*dat fuel pressure

[Steelmesh]

Drag racing result excuses:

- After shifting, the car feels "lazy" where it feels like the power does not come back on like the turbo-only setup. My work mate noticed this we were neck and neck and once I shifted into 3rd he noticed my car just faded away as he passed me
- It's grinding the 1-2 shift and 2-3 shift, killing my shift times here, something is up here and needs attention

I did a bunch of data mining to compare the specific characteristic of Boost Recovery Time between shifts. You can see there is a measurable difference in how quickly the boost recovers in the following data which is a function of shift time and ramp in rate of the boost pressure.  I tried to make an apples-apples comparison so I decided to start the timer when the boost pressure hits 90% max boost (when boost drops to 90% timer starts, when boost raises to 90% of target boost timer stops):

*14 second runs I was letting off, the last one the HPT tablet computer literally flew off my dash and got unplugged

Not sure if this is a transmission issue or a clutch issue.  I'll try to bleed the clutch and check the trans fluid first, otherwise I may need to drop the tranny.

Best Time slip:
ET 13.681 @ 109.16 mph
2.243 60ft
9.040 1/8th @ 78.11 mph

I wasn't good at launching the car, I was launching it hard and trying to slip the clutch on the threshold of slip but easy said than done. Best 60 ft was 2.0 sec and I did that twice, both times I was also spinning some what.  Another launch looking at the data I see I was holding about 47% throttle from 0-33 mph where I immediately go WOT until shifting at about 40 mph, but that was a 2.4 sec 60 ft. 

Lastly I just compared the times it took to go from 0 psi to full boost (turbo vs twincharger), there doesn't look like much difference reviewing the drag racing data from turbo-only and twincharger:


With that info, looks like the shifting (clutch/transmission) problem is holding me back at the moment among other things I suck at.

[MattM]

I can say (having owned a number of them) that the 6 pucked spec stage 3 clutch is not designed to be slipped (should be on and off).  That could be part of the problem with the grinding (i.e. getting it too hot because of slipping at the launch).  Have you driven it since the drag strip?  Is it still grinding or shifting fine now?

I think with the one launch where you completely let off the clutch and modulated the fuel is the perfect technique for a roots blower.  So, next time you go (if the conditions are similar) and you remember that run you'll know if after letting off the clutch completely and giving it 47% throttle you got too much spin you can just give it 30% throttle on the next run.  Or if it didn't spin at 47% throttle you could do the next run at 55% throttle. 

The other thing that is blowing my mind is the performance of the twincharger setup.  Couple of things I would recommend to check to quickly and easily check them off a list of potential problems.  First would be if you could (for just a day at most) Disconnect the turbo piping from the supercharger and run the car only on the supercharger to see (without anything else connected) exactly how much boost you are getting from the supercharger all the way up to redline at WOT.  I know you said that you know how much boost by calculations etc you are currently getting from the supercharger, but this is the only real world way to tell if you are getting the boost you think you are from it. 

Also, you may not even be able to hear belt slippage when you are in the car and gunning it, but another thing that could be happening is the supercharger belt could be slipping and limiting air flow through the supercharger due to it not spinning like it should.  I just think disconnecting the turbo and running off the supercharger for some WOT pulls would be the best way to "go back to the beginning" and double check everything that's been done.

I'd also recommend looking at the bpv on the blower especially if you currently have the turbo feeding the supercharger through the supercharger's bpv and then just have the bpv open the whole time.  If so, could you take the blower's bpv off completely and just run the turbo through the supercharger directly?  That would make sure it isn't accidentally closed and causing airflow issues..

Those would be my recommendations.  I still can't understand how your boost numbers haven't multiplied to a point where you have to turn the turbo's output way down to produce the desired boost levels.  In every compound twincharger setup I've ever seen they've had to lower the turbo's output to modulate boost except for yours.

[Steelmesh]

Dream, Believe, ATM, Achieve


*Just picked it up on the way home from work. Let's say the seller was motivated and I got a great deal, low mileage 33k.

[DeepBlueGXP]

that shift will cost you money.... money shift.  Learned a news term.  Never did it myself.

[Sol Asylum]

that shift will cost you money.... money shift.  Learned a news term.  Never did it myself.

I did, remember that time when you let me drive your car?

[Steelmesh]

that shift will cost you money.... money shift.  Learned a news term.  Never did it myself.

When those front wheel drive cars do it (on drag tires) they almost do a front flip and you can imagine the collateral damage from just that.  With a rwd it's probably more forgiving because the weight transfer would tend to lift the rear tires where a fwd is screwed.

[elff]

Actually Elff it is quite easy to do if you are speedshifting.

I guess if you hold the shift knob the same way for when you shift 1->2 and you do from 3->4
That would allow you to pull it to the left when shifting from 3->4 and accidentally pull it to 2nd gear.

My hand changes positions when I shift
When I shift from 1-> 2 the shift knob is to the left of my hand and my thumb is up
When I shift from 2->3 the shift knob is in between my thumb and forefinger and my thumb and forefinger are horizontal
When I shift from 3-> 4 the shift knob is to the right of my hand and my thumb is pointing down.

When I downshift from 3->2 the shift knob is to the left of my hand and my thumb is up, same hand position as shifting from 1->2

People who hold the shift knob the same way when shifting from 3->4  as they do when they downshift from 3->2 is why they money shift.

Damn that was hard to explain in writing.  I should have just made a video.

[Steelmesh]

I can say (having owned a number of them) that the 6 pucked spec stage 3 clutch is not designed to be slipped (should be on and off).  That could be part of the problem with the grinding (i.e. getting it too hot because of slipping at the launch).  Have you driven it since the drag strip?  Is it still grinding or shifting fine now?

I think with the one launch where you completely let off the clutch and modulated the fuel is the perfect technique for a roots blower.  So, next time you go (if the conditions are similar) and you remember that run you'll know if after letting off the clutch completely and giving it 47% throttle you got too much spin you can just give it 30% throttle on the next run.  Or if it didn't spin at 47% throttle you could do the next run at 55% throttle. 

The other thing that is blowing my mind is the performance of the twincharger setup.  Couple of things I would recommend to check to quickly and easily check them off a list of potential problems.  First would be if you could (for just a day at most) Disconnect the turbo piping from the supercharger and run the car only on the supercharger to see (without anything else connected) exactly how much boost you are getting from the supercharger all the way up to redline at WOT.  I know you said that you know how much boost by calculations etc you are currently getting from the supercharger, but this is the only real world way to tell if you are getting the boost you think you are from it. 

Also, you may not even be able to hear belt slippage when you are in the car and gunning it, but another thing that could be happening is the supercharger belt could be slipping and limiting air flow through the supercharger due to it not spinning like it should.  I just think disconnecting the turbo and running off the supercharger for some WOT pulls would be the best way to "go back to the beginning" and double check everything that's been done.

I'd also recommend looking at the bpv on the blower especially if you currently have the turbo feeding the supercharger through the supercharger's bpv and then just have the bpv open the whole time.  If so, could you take the blower's bpv off completely and just run the turbo through the supercharger directly?  That would make sure it isn't accidentally closed and causing airflow issues..

Those would be my recommendations.  I still can't understand how your boost numbers haven't multiplied to a point where you have to turn the turbo's output way down to produce the desired boost levels.  In every compound twincharger setup I've ever seen they've had to lower the turbo's output to modulate boost except for yours.

I like your ideas for checking stuff out here!  I have time off around the 4th so I plan on doing the trans swap then and also building a 3" dump exhaust; then start looking at some of this stuff. 

I have been dealing with acquiring parts and carb tuning my jet ski after some major mods, it's such a pain in the ass taking the ski apart to pull the carbs just to make a tiny tweak and go out on the water to find it's not good, then repeat repeat repeat.

[MattM]

I like your ideas for checking stuff out here!  I have time off around the 4th so I plan on doing the trans swap then and also building a 3" dump exhaust; then start looking at some of this stuff. 

I have been dealing with acquiring parts and carb tuning my jet ski after some major mods, it's such a pain in the ass taking the ski apart to pull the carbs just to make a tiny tweak and go out on the water to find it's not good, then repeat repeat repeat.

I feel you!  When I owned my previous fun car I had to drop transmissions, mock brackets, tune etc....  It was fun while I was younger and excited about it, but I just kind of got over it.  Now I'm just burnt out on working on vehicles. 

That's why I bought the Sky Redline bc in my mind I could just have a car that could be made pretty fast with only tunes, and I wouldn't have to work on it myself at all.  Now it's kind of turning into having to work on it (something I didn't want to do anymore).  Granted these are stupid little things that woulnd't be a problem for me before, but now It's even worse because I can't work on it at my house since I have no garage and my driveway is on an incline, and I don't really have another place to work on it.  Just sucks now....

[Steelmesh]

I guess if you hold the shift knob the same way for when you shift 1->2 and you do from 3->4
That would allow you to pull it to the left when shifting from 3->4 and accidentally pull it to 2nd gear.

My hand changes positions when I shift
When I shift from 1-> 2 the shift knob is to the left of my hand and my thumb is up
When I shift from 2->3 the shift knob is in between my thumb and forefinger and my thumb and forefinger are horizontal
When I shift from 3-> 4 the shift knob is to the right of my hand and my thumb is pointing down.

When I downshift from 3->2 the shift knob is to the left of my hand and my thumb is up, same hand position as shifting from 1->2

People who hold the shift knob the same way when shifting from 3->4  as they do when they downshift from 3->2 is why they money shift.

Damn that was hard to explain in writing.  I should have just made a video.

If you read it word by word and ghost-knob with your hand in the air, it makes sense.  I might need to get one of these setup at my desk and practice this until it's 2nd nature 

[elff]

LOL
That looks pretty cool

[Uranium-238]

What about one of these?

https://www.summitracing.com/itemgroup/hurst-shifter-t-handles/?ar=1

I've got one on the Camaro, and I really prefer it to a regular ball shift knob. 2-3 feels like a straight push.

[Steelmesh]

What about one of these?

https://www.summitracing.com/itemgroup/hurst-shifter-t-handles/?ar=1

I've got one on the Camaro, and I really prefer it to a regular ball shift knob. 2-3 feels like a straight push.

Always thought those were for automatic classic muscle cars 

But the red button is awesome.

https://youtu.be/GxtSdzgjodk?t=183

[Steelmesh]

Always thought those were for automatic classic muscle cars 

But the red button is awesome.

https://youtu.be/GxtSdzgjodk?t=183

What handle angle do you run?

[marksbug]

 you have to run the angle thats comfertable to you.different hands and arm length as well as seat location will change it.( my bug (sold 3 weeks ago) has a scat dragfast shifter in it,when the wife drove the car and moved the seat,I couldent hardly shift the darn thing)...seat location didnt bother me too much, but shifter did, thats   a easy way to see... on to another thingy...I wonder about the suby/tiodie brz 6 speed trans ratios and making a addaptor for our bell housing.....just thinken...as well as 3.42 cts rear gear...possiably turbo....and head explosion....mine not car's. darn heavy small cars.

[elff]

Umm errr What??

[Steelmesh]

Bad news, when I pulled the exhaust (to fabricate a side dump) I found excessive play in the turbocharger.  This was freshly rebuilt by Precision, maybe 1,500 miles on it.  No way there is an oil feed issue because I monitor oil pressure and the pressure transducer shares a 'T' with the turbo oil feed, in addition I am running a true 12AN drain with no restrictions.  Not sure how high crankcase pressure would cause the bearings to fail either.  I am looking at a Borg Warner S256SX to upgrade to a 1.06 A/R and 3" v-band but I don't know if the frame is a direct swap because it's a tight fit and I am limited to a T3 exhaust flange on the trusty Werks manifold.

In other news, out with the transmission (lost me synchros):


Pro-tip a pro shared with me to get the transmission bolt behind the starter with some ratchet extension ingenuity.  However, the top two bolts still required a remote camera or it will be blind puzzle to test your patience to the extreme to get the socket on each bolt.  The service procedure calls to remove the intake manifold (which actually isn't that hard on the 2.4L), but I sort of have a supercharger and an intercooler so removing all that is a relatively huge job.

Extension setup that worked for me:


Blue circle is the socket on the bolt head, you can guide / feel it with your fingers:


Showing about where the extension feeds behind the starter:





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I've been slacking on the Solstice during this short break off work, but I completed another project on the list.  I started with a stock razor and added a second motor and replaced the motor controller with a cheap low grade one a couple years ago, the scooter was still crappy because the throttle/controller was an on off switch and crappy because it was only 24V with 7 Ah.

Behold the dual-motor lithium 1000w Death Scooter. Range 8 miles, top speed 25 mph:


Kelly Controls programmable motor controller, using a variable throttle:



*my hand was feeling the heat, LED light on high draws 2.5 amps!!

8S Lithium "LiPo" nano-tech packs.  That is 8 lithium cells in series, at 12 Ah.  Nominal energy is about 355 Wh, where nominal energy of the stock lead-acid setup is only 168 Wh; translation, the lead-acid setup for the same volume is 1/2 the energy while being 3x heavier!!  Wh = watt hours, for those unfamiliar with electric vehicles, Wh is common language to describe the amount of range a battery pack can provide where cars are measured in kWh, for example my Volt will use about 10 kWh to travel about 35 miles.  My Volt uses about 285 Wh per mile, the death scooter uses about 44 Wh per mile.


During testing, I killed a cell in one of my packs so I've ordered a BMS to limit current when any cell hit's bottom to prevent this lithium firebomb from exploding. Also to charge, I need to pull out each pack and charge them with a RC charger individually with a 4-pack charger, but I have enough packs to keep charged and swap out.

[MattM]

I figured something was up because of the fact that boost wasn't multiplied....i bet once you get the turbo fixed you will have to lower boost from the Turbo niece everything is fixed!  On the bright side at least you figured out what the poor performance was.

[Steelmesh]

I figured something was up because of the fact that boost wasn't multiplied....i bet once you get the turbo fixed you will have to lower boost from the Turbo niece everything is fixed!  On the bright side at least you figured out what the poor performance was.

Yes it both sucks it's worn out but good I found it before anything bad could have happened.  Also, I'm going to drill my front driveshaft bolts to safety wire, some of those were loose even though I loctite and torqued them, yikes!

[MattM]

Beyond that, you could have been looking for a while trying to figure out where the problem was...

[Steelmesh]

I got an AGP 5757 on the way with a 1.06 A/R and a 3" v-band exhaust, should bolt right in after welding the compressor outlet elbow in the same place.  I was already fixing to build a 3" downpipe/side dump when I caught the shaft play issue,  consider the old 5-bolt turbine housing was only a 2.5" exit too.

https://agpturbo.com/agp-turbo-z2-5757b-billet/

Precision 5557 = 495 hp rated
AGP 5757 = 625 hp rated

[MattM]

Awesome!

[Steelmesh]

The turbo finally showed up 2 weeks later 



Big Snail:



That -12AN turbo drain wasn't fun to work with, so I am going to try to weld up an engineered tube (3/4" OD).  The tube is from a 1996 S10 Blazer heater core in the scrap pile.