mkriebs

We can get them powdercoated! Our orange ones started out polished like those, we had them bead blasted and powder coated.

SKY888

what are the sizes of the orange wheels? front and rear? 18" x ?

and what offset?

what tire sizes?

Saab95

two turbos to make 600 hp? lame..

SKY888

Yes, double of what you're making

mkriebs

The orange are 19's, same size as the ones we are selling now. The orange ones have Hoosier slicks on them. Not sure on the offset.

SKY888

thanks for the info Matt.

I thought that the orange ones are 18". Wrong guess...lol

Yeah, too bad Werks' sale is on 19" wheels. I'm looking for only 18"......

mkriebs

Bah! If we had more wiggle room on our orders from CCW, I would say I would talk to Dave for you, but we really don't (trust me, I tried to get some for the Balt).

Terminator2

Feeding 14.7 + 8 psi = 22.7 psi inlet pressure into the GT40R will help it. Think of how much more power cars would make if 1 atm = 22.7 psi instead of 14.7 psi. Not sure what the pressure coming out of the 40R but......

mkriebs

Also the fact that 8psi out of a 40R is a helluva lot of flow.

oldskool

I've been following this thread on solsticeforum, but as usual, there seems to be more technical discussion elsewhere .

Looking at the GT40r compressor map, it looks like you can get efficient power up near 30 psi.



Most cars (on a quick google search) in the 600hp range are running 25-30psi out of the GT40r alone. I bet you can break well over 600hp, but it's not going to be out of 8pounds on the big turbo. You can spool it earlier, but i don't think compounding will cause the bigger turbo to make that much more power on less boost.

But regardless of my speculations, i'm very excited to see this done

EDIT: quick final thought - why not 10-15lbs out of the gt2871 and 20-25 out of the gt40r. If it were me, i'd see where a 10/25psi split puts you.

mkriebs

Problem with this is thats not how it would work. Consider the flow in lbs/min, the smaller turbo will not be able to flow less pressure than the big turbo because it takes higher pressure to flow the amount that the bigger turbo would flow. What the compounded turbos are going to do is just compress the air further, while not increasing the boost as much. IDK, I had this all thought out, then lost my train of thought. I would push the split you mention, but the other way... 25/10.

oldskool

Yes I'm trying to picture it in my head too.

Sky888's plan:
So one turbo is not further compressing already compressed air, unless I'm misunderstanding this set-up. The small turbo is fed from the engine and draws it's own fresh air, and the turbine outlet/wastegate dump feeds the bigger turbo. The bigger turbo also draws it's own fresh air, and each compressor feeds a single IC - each adding it's own volume/cfm of air.

He also stated that the exhaust flow would be more akin to that of a 4-6 liter engine, which makes sense to spool the relatively mammoth GT40r somewhat earlier. To hit 600hp, there will be a compromise of pressure run from each turbo to get max power versus boost threshold/power onset. If you were willing to run a combined pressure of 50lbs you could get the best of both worlds But if the arbitrary cap is 35psi or so, you have to choose the split wisely to achieve your goals.

But like i said, props for going through with this and i can't wait to see the results.

EDIT: ok upon doing some more reading, it seems like the larger compressor feeds through the smaller one. So my babble above is out the window

mkriebs

Umm, his order is odd compared to what I am used to in compounded turbo setups. The small turbo will be on the exhaust manifold, and then a DP will go to the bigger turbo, the bigger turbo will draw its own, fresh air, compress the air, and then send it to the smaller turbo's inlet, where the smaller turbo will compress it again, and send it to the IC, then to the engine. If that makes any more sense, lol. Its fairly complex.

The advantage to this, that I have deduced on my own, is that the smaller turbo will spool quick, in turn sucking air through the big turbo, which will compress the air, and send it to the small turbo to be compressed more...

Its not that the exhaust is any more, its the fact that the pressure from the small turbo is acting on the bigger turbo to get it spooled quicker. The big turbo is the power maker, whereas the small turbo is the spooler.

Agh, I hope I am explaining this right and clearly, haha. I have been trying to understand compound turbos better lately, because I am contemplating doing a set on my truck.

JL-KA

iTrader: (4)

My head hurts

jimbos'ss

iTrader: (2)

i'm sorry, how's trionic 8 working out for you?........can you even bolt on a turbo to support 65lb/min airflow without going standalone?

Cobalt_Daddy

lol i thought the idea of compounding turbos was to reduce lag and still make power up top? why is everyone so concerned with having one giant turbo? i think it's a neat idea ... smaller turbo for instant power and big turbo for power higher in the powerband... isn't that the idea? don't over think it people lol besides it's obviously works..

mkriebs

It is, but the people that are supporting one big turbo aren't looking at driveability and power band, only peak numbers. they are also looking at the ease of install (which is the BIG downfall on compound turbos, right before the cost of the setup. I am willing to bet that for every ten people that say 'go with one big turbo' not one of them have driven a compound turbo setup, much less a big turbo setup (especially on a 2.0 liter motor).

SKY888

yes the small turbo will act as a multiplier of the boost from the large turbo.
but no, I will only be be boosting a total of 28-35 psi only.

you want the boost pressure from the big turbo, or the inlet pressure of the small turbo (same thing), applied to the top port of your small turbo WG. When the big turbo makes 1 psi, the small turbo will raise its output 1 psi. Otherwise you'll never get full boost, unless you set the boost controller for the small turbo at full boost, but the problem with that is that you'll be working the small turbo hard until the big turbo spools.

So basically, once the small turbo spools at 20psi.......and the big turbo starts spooling.......every 1psi that big turbo produces the higher my total psi will become.

for example:
small turbo 20psi + big turbo 1psi = total of 21psi (manifold)
then when
small turbo 20psi + big turbo 4psi = total of 24psi
then
small turbo 20psi + big turbo 8psi = total of 28psi

then after that
small turbo will stay at 20psi and big turbo will go up in boost = total will keep on going up til 28psi (up to 35psi).


that will be what I'm doing. I'm following what Kevin Jewer did. I am not sure if you see him on one of the dsm forums (kjewer). We've been communicating for the past month, and he highly recommends this set-up since his compound set-up produced 600whp (28psi small turbo + 17psi big turbo)....total of 45psi I believe.

To usehis big turbo as an example, it would be perfectly happy making 45 psi on his 2 liter motor moving 80 lbs/min. But, being set to only 17 psi it still moves 80 lbs/min. In his case the T3 50 trim is at 2:1 moving 80lbs/min. At first you'll be like WTF, that's off the chart to the right! But remember that "perceived" airflow, or what the small turbo feels like it's moving, is total airflow divided by the PR of the big turbo. So the 50 trim feels like it's moving 38lbs/min, for the sake of plotting on the chart.

that particular WG plumbing arrangement is what makes the two boost pressure additive


no need to boost very high to get 600hp........since the small turbo is re-compressing an already compressed air (produced by the big turbo) ......

I will follow what kevin did. What's working well for him is running the big turbo just regulating it's output pressure. The small turbo has manifold pressure to the side port and add it's inlet pressure (big turbo outlet pressure) to the top port. My small turbo will come up and make 20 psi and then the big turbo starts to make boost and as it comes up its output pressure is added to the small turbo's spring rate via the top port. Total boost ends up at 28 psi. It's additive in this configuration. What's nice is that the small turbo is never really asked to make more than 20psi. As manifold pressure comes up to 28psi, the small turbo's pressure ratio actually goes down. Then I will just put an MBC on the big turbo for more boost control.

this is what kevin who has a very succesful compound turbo set-up told me, and also using it on his compound turbo set-up. Boost pressures are additive in this configuration......

in a compound set-up, pressure ratios of the turbos are not additive but are multiplied though......

so on the compressor side, if I run both turbos at a 2:1 pressure ratio, which is equivalent to about 15 psi around sea level..........I'll end up 45 psi instead of 30, and neither turbo will be choking.....


but I will not go as high as 45 psi though......since I will be using lower pressure ratios.....

SKY888

hi matt..what are you used to in regards to compound turbo? Please let me know what other set-up?

The small turbo will be on the exhaust manifold, and then a DP will go to the bigger turbo, the bigger turbo will draw its own, fresh air, compress the air, and then send it to the smaller turbo's inlet, where the smaller turbo will compress it again, and send it to the IC, then to the engine. If that makes any more sense, lol. Its fairly complex. Yes, this is what my compound set-up will be. The small turbo will re-compress an already compressed air


I try to boost it as around 20-22psi......so I can boost the bigger turbo faster. The less psi the small turbo boost.......the slower the bigger turbo will spool.

Imagine a 22psi gt2871 turbo on an ecotec engine.......as a one big engine (V8 for example). This v8 engine.....will just power the gt4094 easily.

SKY888

the small turbo will not have an air filter. Only the big turbo draws big air.

The small turbo's inlet will be connected to the big turbo's compressor.

The small turbo is the multiplier in a compound turbo set-up.......since it will be re-compressing an already compressed air That's why the boost doesn't need to be as high compared to a single turbo set-up, which we are so used to.


I explained some stuff on my earlier post.

hopefully they help.


I am NO expert....I am still learning every step of the way

mkriebs

This is what I am used to mostly. I have seen some wild setups in the diesel world, but this is most familiar, and seemingly the easiest/most effective way to do things.

80vetteL82

I wanna know when its time to tune it so I can come down to SMG and check it out!

I understand how the setup works, but Im confused on one thing. If the big turbo (which is capable of spinning and boosting more) is feeding a smaller turbo (which cant put out as much as the bigger turbo) wouldnt it be wasting the bigger turbos capabilities? Im sure Im just not thinking about it right, but I figured Id ask....

SKY888

I'm confused! lol!

I thought you said, my order/set-up is odd though?



yeah....the diesel world is the beast, in regards to compound turbos. I've seen a tractor pulling massive tons of loads.....with triple compounded turbos!

crazy..indeed!

mkriebs

Guess I meant more the way you worded it was odd. To me it sounded like you were gonna have fresh air on both turbos. I see now though what you meant.

SKY888

sorry for the confusion.

yeah, only the big turbo has an air filter.

small turbo's inlet is connected to the compressor outlet of the big turbo.