My compound turbo set-up

[FastTSiAWD]

More like a 16G that flows 75 lbs/min.

I'm betting that one of Paul's biggest motivations is that nobody else has done it (at least not to that extent). He battled through it, learned a crapload along the way, and ended up with something that is not only extremely unique, but just plain bad-ass performance-wise as well.

Can't wait to see what he has up his sleeve for version 2.

Yeah, Pauls my inspiration for my build - 2.3L Stroker with Eagle 100mm Crank, Pauter Rods, CP stroker pistons, BR Stage 3 head, Kelford 272's, TRE "High Torque" Transmission, ProEFi Pro128 EMS, etc...

We haven't decided on the turbos as of yet though. I'm hoping to have the car finished by December, it's currently under the knife as we speak

Oh, and Paul, we need some numbers!!

 

[GRAVEDIGGER]

75lbs/min on a 60-1? That seems pretty generous. I thought the 60-1 maxed around 60lbs/min.

750whp at 4k would be pretty damn impressive. I dont know if i would believe it really. Has this car seen the dyno yet?

I think you need to go back and review how a compound turbo system works and what the benifits are. Basically this type of system offers great low end spool characteristics with excellent top end as well. Not to mention the fact that the boost from both chargers gets "compounded" or combined to give you more boost to the engine than would be possible with just one of the given chargers by itself.

 

[dsm-onster]

But it doesn't increase the final flow which is the flow of the primary stage. The 16g is bypassed on the exhaust side. So it doesn't restrict. The compressor is being fed boost from the 60-1 and then compresses it more. Yes the boost goes up, but the flow is limited by the 60-1 compressor. Which is about 60lb/min. Let's not confuse boost with flow.

The truely impressive thing here is what is being done with such a large hotside. Paul's setup uses a t4 hotside with a laggy turbine wheel. Not to mention the compressor wheel is 70s tech and not very efficient. . . . Imagine what could be done with the same high flowing hot side plus a modern tech compressor wheel like the billet 6765 compressor wheel or some of the big hta compressor wheels out there. Compressor wheels have a relatively small effect on spool. So such a large hotside getting to such a high threshold so quickly really makes your head spin thinking about what compressor he could use to eat drivetrain parts.

 

[GRAVEDIGGER]

Sorry, I didn't mean to cause any confusion between boost and flow. I quoted the wrong post. I meant to quote and to respond to this one...

"Im sorry ive read all 20 pages and i just dont see a use for the compound set up. Unless your towing your track car with this car i dont see how any of that ^^ matters at all. Its not like we need to roll into power like semi's hauling a load. Down shift or break boost on a roll and your there. Im not dissing your ride at all. I seen it at shootout this year, very clean . Im just trying to understand why the project hasnt been dropped yet for a larger single. I mean really dont you just have a slow spooling 16g? Again im not dissing on anything in this thread just trying to wrap my head around it i guess."

Sorry again for any added confusion fellas.

 

[99gst_racer]

Im sorry ive read all 20 pages and i just dont see a use for the compound set up. Unless your towing your track car with this car i dont see how any of that ^^ matters at all. Its not like we need to roll into power like semi's hauling a load. Down shift or break boost on a roll and your there. Im not dissing your ride at all. I seen it at shootout this year, very clean . Im just trying to understand why the project hasnt been dropped yet for a larger single. I mean really dont you just have a slow spooling 16g? Again im not dissing on anything in this thread just trying to wrap my head around it i guess.

You need to go for a ride in the car. I'm not one to brag at all, but I don't think I single person has felt disappointed after going for a ride.

The sooner powerband is just awesome for street driving. It's even incredibily noticible at low RPM and part throttle. Large frame, single turbo cars are typically guttless before boost comes in and when it does come in, it's like a freight train. It leaves much to be desired in the lower RPMs that a street car opperates in, and it's a constant battle to retain drivetrain parts from the heavy power hit when boost does come in. With the compound set-up, boost comes on much, much sooner, smoother, and more gradual. It's less of a "on/off" type hit. My boost curve is unlike any single-turbo set-up that's I've ever seen. I honestly feel that has alot to do with why I'm getting away with not breaking any of my drivetrain parts thus far and also explains why I don't have traction issues on street tires at all.

There's so many small, side benefits to compounding, it's not even funny. And I honestly feel that my current configuration has alot of room for improvement. I can't wait to get started on the next set-up.

 

[dsm-onster]

Sorry, I didn't mean to cause any confusion between boost and flow. I quoted the wrong post. I meant to quote and to respond to this one...

"Im sorry ive read all 20 pages and i just dont see a use for the compound set up. Unless your towing your track car with this car i dont see how any of that ^^ matters at all. Its not like we need to roll into power like semi's hauling a load. Down shift or break boost on a roll and your there. Im not dissing your ride at all. I seen it at shootout this year, very clean . Im just trying to understand why the project hasnt been dropped yet for a larger single. I mean really dont you just have a slow spooling 16g? Again im not dissing on anything in this thread just trying to wrap my head around it i guess."

Sorry again for any added confusion fellas.

Oh ok. I think 91stocker is coming around. . . Just be patient

 

[schroder]

Having fast spool is a street thing. VERY large single turbo hotsides are a race track thing. Very fast spool of very large hotsides is an EVERYthing.

Just to add to it, its not just a street thing. Look at the Auto's as a prime example. Even with a high stall, we have to use nitrous to bring on a big turbo, but it can be inconsistent. Using a smaller turbo compounding a larger turbo GREATLY helps the auto guys out, even at the drag strip. Kevin Jewer's RWD talon is a great example. Also, think about what the guys on the 16g's are doing with the autos. The 16g is about the largest turbo you are going to get to spool on a stock stall converter, and thats with a stroker. Imagine what happens if you add a 2nd, larger turbo, on top of that. Suddenly, you could run a 16g and an HX35 (stock exhaust housing), and really be able to move some air with great spool characteristics. This setup can benefit anyone who is willing to put the time and effort into it.

 

[91stocker]

Oh ok. I think 91stocker is coming around. . . Just be patient

Very possible but..

I guess my last post didnt come out right, no confusion here on boost and flow. What i was trying to ask is the 60-1 flows 60lbs max how are you flowing 75lbs?

 

[99gst_racer]

But it doesn't increase the final flow which is the flow of the primary stage. The 16g is bypassed on the exhaust side. So it doesn't restrict. The compressor is being fed boost from the 60-1 and then compresses it more. Yes the boost goes up, but the flow is limited by the 60-1 compressor. Which is about 60lb/min. Let's not confuse boost with flow.

This has been a constant learning process for me, so I'm not going to claim to be able to answer any and all questions pertaining to compounding quite yet. But I believe you're confusing volume flow and mass flow. Volume flow does not account for air density. Compressors are rated with mass flow to account for increased air density. Mass flow is essentially volume flow multiplied by air density. So, I'm able to outflow my larger compressor due to having a more dense air charge, which increases my overall mass flow to an amount beyond the means of the larger compressor by itself.

At least, that's how it makes sense it my head. And my datalogs back this up as well. PM me your e-mail address, and I'll send you one to look at, Matt.

 

[99gst_racer]

75lbs/min on a 60-1? That seems pretty generous. I thought the 60-1 maxed around 60lbs/min.

See the post above.

750whp at 4k would be pretty damn impressive. I dont know if i would believe it really. Has this car seen the dyno yet?

I know I'm not making power like that at that RPM. But the added low end torque is what's impressive. Something to actually get the car moving before peak HP.


I'm now penciled in for some dyno time Thursday afternoon of next week. And I'm shooting for Sept 3rd for some track time, as long as everything goes as planned.

 

[91stocker]

Very interested in how the runs turn out. I found a few good reads on volumetric flow vs mass flow.

Thanks and pm sent. If it all holds true that will indeed be a very impressive set up.

 

[FastTSiAWD]

I'm now penciled in for some dyno time Thursday afternoon of next week. And I'm shooting for Sept 3rd for some track time, as long as everything goes as planned.

I can't wait to see the results man

 

[dsm-onster]

This has been a constant learning process for me, so I'm not going to claim to be able to answer any and all questions pertaining to compounding quite yet. But I believe you're confusing volume flow and mass flow. Volume flow does not account for air density. Compressors are rated with mass flow to account for increased air density. Mass flow is essentially volume flow multiplied by air density. So, I'm able to outflow my larger compressor due to having a more dense air charge, which increases my overall mass flow to an amount beyond the means of the larger compressor by itself.

At least, that's how it makes sense it my head. And my datalogs back this up as well. PM me your e-mail address, and I'll send you one to look at, Matt.

I'm PMing you my email right now. I want to see how a primary stage can flow more than it is capable of. Nothing is feeding it. . .

If it does, well then just wow! Raise the boost, raise the post compressor flow; still the compressor has to match the flow. . .

 

[99gst_racer]

I'm PMing you my email right now. I want to see how a primary stage can flow more than it is capable of. Nothing is feeding it. . .

Just so we get our terminology consistent, the primary is the one receiving exhaust first and the one receiving a higher atmosphere. So, my 16g is considered the primary. I'm currently running the 16g at 14 psig and the 60-1 at 29 psig. The 60-1 definitely isn't flowing 75 lbs/min by itself, but after the air density change from passing through the 16g compressor, the engine is seeing 75 lbs/min mass flow. Follow?

E-mail sent.

 

[dsm-onster]

Glad the terminology is straight. I mean the OPPOSITE . . . I will take a look at your logs asap. I think this setup is one to alter the current understanding of our platform, so don't throw me into the mix as seen of recent, Paul.

 

[Kevin Jewer]

Paul, how the #### did we not run into each other at the SO?!

I've always seen the primary/secondary terminology applied to the compressor only. Look at a 2 stage air compressor for example, since it has no turbine. The atmoshperic stage is the primary, the second stage is, well, the secondary stage. It's all about the compressor from what I've seen, the turbine gets no love.

I don't think it's possible to outflow the primary/atmoshperic stage, that should be a solid limiter for mass airflow. But I'm open to the possibility. I don't think I'll ever find out on my car, I'm at 90 lbs/min and my primary is good for ~110 by itself. I gather from your posts Paul that you're already over the 60-1 limit, and I'm assuming your airflow sensor is well calibrated. What have you seen for flow?

For those that still doubt compound turbo systems, my setup with a 50 trim and a T6 1.32 BW S475 just went 8.80 at 156 tonight. I wish it could have done that last weekend in Norwalk of course, but whatever, story of my life.

 

[Calan]

Paul, how the #### did we not run into each other at the SO?!

Paul was always passed out under a picnic table somewhere. (j/king)

That's a good question... I can't believe you guys didn't hook up and compare notes.

I about sh*t when you said "did you check out the compound turbo setup?". Took me a minute to realize what you were saying...I had stared at your car for 5 minutes and never even noticed that you were running another turbo under that beast on top now.

 

[Kevin Jewer]

Watching people at the track, only about 10% of them see the other turbo.

 

[Calan]

Well it's hidden pretty well underneath that planet-sized snail on top.

 

[99gst_racer]

Paul, how the #### did we not run into each other at the SO?!

I was checking out your car at Buschurs on Saturday, but I wasn't sure who you were in the crowd. And I was going to come find you on Sunday in the pits, but I just could quite talk myself into leaving my shaded seat all day. I'll be there again next year, and I hope to see you there too.

I don't think it's possible to outflow the primary/atmoshperic stage, that should be a solid limiter for mass airflow. But I'm open to the possibility. I don't think I'll ever find out on my car, I'm at 90 lbs/min and my primary is good for ~110 by itself. I gather from your posts Paul that you're already over the 60-1 limit, and I'm assuming your airflow sensor is well calibrated. What have you seen for flow?

I honestly really do feel compounding is a way to increase mass flow beyond the capabilities of the larger turbo. I'd be willing to bet that if you bumped up the boost to 60-70 psig, you would see airflow numbers beyond what your primary compressor is capable of on it's own. I don't think I can run much more than 55-60 psig boost max on my current set-up, so I'm already pushing mine to roughly 75-80% of it's maximum capacity. With your compressors, however, you have a long way to go before yours are maxed out. And that's probably why you aren't seeing airflow numbers that exceed the primary compressor's max rating. That's my theory at least.

Mine is well calibrated. With meth injection, I'm currently seeing about 41-42 PSIg boost, and I'm netting 75 lbs/min airflow @ 8K in 3rd gear. And more recently, if I ride it out another 500 RPMs, I pick up another 5 lbs/min. Hopefully my dyno numbers and trap speeds can back up these airflow numbers.

For those that still doubt compound turbo systems, my setup with a 50 trim and a T6 1.32 BW S475 just went 8.80 at 156 tonight. I wish it could have done that last weekend in Norwalk of course, but whatever, story of my life.

Hell yeah! The more I hear of your sucess at the track, it makes be want to put the compound set-up on my 1G AWD and make it's a single digit track car.

 

[Kevin Jewer]

I was checking out your car at Buschurs on Saturday, but I wasn't sure who you were in the crowd. And I was going to come find you on Sunday in the pits, but I just could quite talk myself into leaving my shaded seat all day. I'll be there again next year, and I hope to see you there too.

I was mostly under the car working on adjusting the ladder bars. I feel like I missed the whole Saturday thing.

And ####, now I'm gonna have to see how much air I can move with this setup at some point. Damn you for challenging my assumptions!

Hell yeah! The more I hear of your sucess at the track, it makes be want to put the compound set-up on my 1G AWD and make it's a single digit track car.

That's the spirit! Instead of selling the current setup, put it on an automatic AWD 1g and mop up at every event you go to.

 

[highlandgst]

Cant wait to see the dyno

 

[wishihadatalon]

I hear it made a metric #### ton of tq

 

[mike96]

Question... call me crazy or stupid even, but humor me for a second on this one. what do think one would expect from a T25 pumping into an Evo3 16G/20G? i know sounds pointless why have a small turbo pumping air into a small turbo... the theory... my engine is already built to handle 600HP, i have both turbos already so with the exception of some plumbing and some larger injectors i have about 75% of the big parts, from what i have read the t25 should spool up about 2500 RPM but runs out of steam about 5500, and the EVO3 16g hits 20+ PSI in my car about 3800 and from what i remember holds pretty well most of the way to redline (it has been a while since my car has been on the road so i am not entirely sure).

here is what i am thinking, with the T25 pushing the E3 it should spool like a rocket and be more than capable of pushing the 400 - 450 WHP mark without breaking a sweat. i am not the greatest at doing the math so maybe someone could clarify my theory. 10-11 PSI on the T25 and 15-16 PSI on the E3 to me sounds like a lot of fun... either that or it would be an interesting way to turn your gas pedal into a big on/off switch.

i know there are a few people pushing the 500 WHP with just the E3 turbo and E85 but to be able to get it there that much sooner without having to push it to PSI limit...

 

[GRAVEDIGGER]

Question... call me crazy or stupid even, but humor me for a second on this one. what do think one would expect from a T25 pumping into an Evo3 16G/20G? i know sounds pointless why have a small turbo pumping air into a small turbo... the theory... my engine is already built to handle 600HP, i have both turbos already so with the exception of some plumbing and some larger injectors i have about 75% of the big parts, from what i have read the t25 should spool up about 2500 RPM but runs out of steam about 5500, and the EVO3 16g hits 20+ PSI in my car about 3800 and from what i remember holds pretty well most of the way to redline (it has been a while since my car has been on the road so i am not entirely sure).

here is what i am thinking, with the T25 pushing the E3 it should spool like a rocket and be more than capable of pushing the 400 - 450 WHP mark without breaking a sweat. i am not the greatest at doing the math so maybe someone could clarify my theory. 10-11 PSI on the T25 and 15-16 PSI on the E3 to me sounds like a lot of fun... either that or it would be an interesting way to turn your gas pedal into a big on/off switch.

i know there are a few people pushing the 500 WHP with just the E3 turbo and E85 but to be able to get it there that much sooner without having to push it to PSI limit...

The evo 3 already spools up so quickly that it really wouldn't benifit enough to make a compound setup with it as with the large turbo. The main benifit of compounding is that you can have a big turbo which normally would take forever and a day to spool up and combine it with the smaller turbo so you can build boost quicker and easier, giving you the best of both worlds. Good idea, but I just don't think it is practical or will make that much difference for all the work it would require.