Compound Charging

[killer_datsun]

what do u guys think it would take to make a twin turbo and a supercharger set up work well??

[calereeves]

Tons of intercooling. But the real question is why?

[killer_datsun]

well I know some diesels use the compound charging, and u might be able to get more boost into the engine from it, and part of it is because I would like the challenge to do it

[boodlefoof]

I've heard of doing this before, but am not familiar with how you would get them to work together.

Do you plan on using a small supercharger for off the line performance and then a large turbo to pick up where the supercharger begins to fall off? This is the way I've heard of it done...

However, I have to ask... why not use the supercharger solely to spool the turbine side of the turbo? By gearing up the supercharger, you could probably decrease spool up times even with an enormous turbo.

I've never heard of this being done before, but it seems like a good idea, and possibly less complicated than trying to force feed the engine with both the turbos and the supercharger.

[ballistic69]

You would have to do something like this. Diesels are running up to 150 psi of boost.one turbo feeding into another

[derekf]

There was a Lancia rally car in the late 80s that was both super- and turbo-charged. If memory serves, there was an RPM where the intake changed over from the SC to the TC.

A google search found some info:
(from http://www.carsfromitaly.com/lancia/deltas4.html - you'll have to click the "Delta S4" link, their page redirects if it's outside its frames)

The unusual route of using a supercharger and turbocharger together was to avoid the poor performance of the large turbochargers at low engine speeds. On the S4 the order, from the air intake was turbocharger, intercooler, supercharger, intercooler, inlet manifold. Once the supercharger became less efficient, at higher engine speeds where the turbo performed better, a bypass allowed the turbo to feed the engine directly.

http://www.lanciaaustralia.com.au/pa...es/rallyhq.htm says

A special bypass valve cut out the supercharger after 5000 rpm. On gravel the two forced induction systems worked together up to those revs when the turbo took over. The benefit was the low rev torque by the supercharger assisted in removing the turbo lag which had made some developing turbo cars difficult to drive.

[Blown353]

well I know some diesels use the compound charging, and u might be able to get more boost into the engine from it, and part of it is because I would like the challenge to do it

The diesels you are referring to are likely 2-stroke diesels (probably the detroit "V" series, they're quite common) and they NEED the positive displacement supercharger to function; they don't have a "normal" intake stroke to suck in the air and need to have the air shoved in-- thus they need boost all the time and that's where the positive displacement supercharger comes in.

The new Euro-market VW TDI's are using twincharging to help with the low end power and emissions. Some MR2's also used twincharging around '87. I remember Koenig offered a twincharged engine package for Ferrari Testarossa's back in the late 80's too. Lots of piston aircraft engines from the 30's/40's/50's used twincharging with intercoolers between each stage and also turbocompounding, but that's another thing entirely.

You could probably make your own by piecing together factory parts; use an electromagnetic supercharger clutch from a new 'Benz and run a servomotor or have a diaphram type actuator trigged by manifold pressure and controlled via a solenoid valve to actuate a bypass valve to transfer from the supercharger to the turbocharger based on engine speed/load.

Honestly, I think you would better spend your efforts adapting a VNT (variable nozzle turbine) turbo than spend time to make your own twincharged setup. VNT turbos if done right can have very good low end performanace will still having good top end. Unfortunately I don't know of any "aftermarket" VNT setup; you need a way to monitor engine load/speed and a backpressure sensor to control the VNT vanes, which are usually controlled via oil pressure and an electronic regulator. They're becoming quite common lately from OEMs; mainly on diesels but on gassers now too.

Troy

[Bjkadron]

New stuff anyone? you can thank me later for bringing back the old thread.

I am thinking about doing this with my starion. So I figured I'd bring it up again...

The Ford thunderbirds and other eaton setups use a vacuum bypass... you could do the same thing with boost...

Hellion makes a setup for the gt500: http://www.hellionpowersystems.com/i...article&id=140

And FAQ: http://www.hellionpowersystems.com/i...boost-resource

And their is a compound-charged exige floating around somewhere but I can't find much solid info on it other then in magazines.

[Ash]

I'd say Twin-charging shines with smaller displacement engines. As Derekf was describing with the Lancia, that's the whole reason it was embraced back in the "Group B" days of rallying : getting insane levels of horsepower out of relatively benign 4 and 6 cylinder engines. The supercharger only handles all the low RPM Grunt, then after the turbo is sufficiently spooled, the bypass valve kicks in,the supercharger ceases in it's duties, and the turbos take over for the mid/high RPM fun. The only reason the public saw some of those cars was to satisfy the homologation requirements.

There are some truly wicked twin-charged L32 series II/L67 series III 3800 V6's, as well as 2.0L cobalts, and Nissan VQ's. Don't get me wrong, a twin-charged built V8 is pretty trick, but as calereeves stated, "Why?". Dropping astronomical numbers on a dyno, or quarter mile juggernaut aside, the usability of all that torque/HP on a street driven car comes into question (not that you aid it was for a street car, but ....you know). I'm not a naysayer by any means, I say go for it. A sizable engine will need sizable turbos and superchargers.

There are so many possible configurations though. By your post, your eluding to a single Supercharger and two turbos. What engine are thinking of using? Street/Strip or drag, fuel injected (I hope!!), horsepower?

[Bjkadron]

I'd say Twin-charging shines with smaller displacement engines. As Derekf was describing with the Lancia, that's the whole reason it was embraced back in the "Group B" days of rallying : getting insane levels of horsepower out of relatively benign 4 and 6 cylinder engines. The supercharger only handles all the low RPM Grunt, then after the turbo is sufficiently spooled, the bypass valve kicks in,the supercharger ceases in it's duties, and the turbos take over for the mid/high RPM fun. The only reason the public saw some of those cars was to satisfy the homologation requirements.

There are some truly wicked twin-charged L32 series II/L67 series III 3800 V6's, as well as 2.0L cobalts, and Nissan VQ's. Don't get me wrong, a twin-charged built V8 is pretty trick, but as calereeves stated, "Why?". Dropping astronomical numbers on a dyno, or quarter mile juggernaut aside, the usability of all that torque/HP on a street driven car comes into question (not that you said it was for a street car, but ....you know). I'm not a naysayer by any means, I say go for it. A sizable engine will need sizable turbos and superchargers.

There are so many possible configurations though. By your post, your eluding to a single Supercharger and two turbos. What engine are thinking of using? Street/Strip or drag, fuel injected (I hope!!), horsepower?

Yes, the torque should be mindboggling! I was actually going to try it on my Starion. It has a turbo 4-cyl but the torque isn't that great at all until the turbo spools. Yes, it is a street car.. And a triple threat car(roadrace,drag, and auto-x and anything else I can find). The torque isn't as important on the strip but if you fall out of the power band in a corner it really stinks... I have a eaton m90 supercharger which should be plenty for a 2.6(g54 I believe) in the lower rpm range. Yes, fuel injected. I'll probably shoot for somewhere around 300hp at the wheels with the same torque. not much.. but it is a 4-cyl. It is a great idea... and with all the hoopla about downsizing engines I'm surprised People haven't already embraced the idea already!

[Ash]

Well, the G54B is throttle-Body injected, and I have no earthly idea how that would work with twin-charging (or if it's even an issue).

EDIT:Found this in reference to a thread on a Eaton 62 series on a TPI V8. The response is to Another persons post on how the eaton is not designed to have a air/fuel mixture passed through it, and how it may damage the unit over time. He mentioned it's stated on eatons website, but provided no link. No idea if either are correct "Yes, it can be done. Throttle body fuel injection is still fuel injection. It doesn't matter if the throttle is upstream or down stream of the injector. So just place another throttle body on the intake of the supercharger and run your throttle body on the intake manifold at wide open. To keep it simple, use the same throttlebody on the supercharger so you can run the tps sensor and idle speed on the supercharger, you just wont need the injectors. Then pipe the supercharger outlet to the "single point fuel injector". Then youll have to work some sort of fuel enrichemt system, not sure if a rising rate fuel regulator would work to well. You would be better off with the Ford eaton 90 though, from the front of the pulley to the back of the supercharger its 15 1/2 inches long as opposed to the gm eaton 62 wich measures 19 inches long. Shorter is better, the firewall tends to get in the way of progress"

. If it's a major issue, and you want to keep the stock engine, http://www.g54b.com/cgi-bin/yabb2/YaBB.pl has a whole section dedicated to converting from throttle body to Multi-Port Injection. On the conservative side, under $2,000 for this mod. The G54B is a mostly forgotten engine....as far as the aftermarket is concerned. If it's all garage/junkyard tech though, nothing stopping you from being the first. I'd love to see it done.

Not to hop off topic of what your shooting for, but if the G54B is too involved or wallet emptying, take a look at the 4G63 swap. IMHO, seems like the much better option. Comparable to the GM LSX, Honda B-series, Toyota 2JZ, Mazda 13B, or Nissan RB....Tried and true. Twincharging would not be needed, 300HP wont be a problem, and it would be futureproof once you want to turn up the wick. The aftermarket support, compared to the stocker, isn't even comparable....the 4G63 came in the Evolution until 2006. http://www.projectzerog.com/ There are a plethora of different swaps in this chasis, but I'd go for the 4G63 above all. Check out the feature sections of turbomagazine.com, superstreetonline.com, Importtuner.com, Or modified.com to see the numbers the engines are capable of, and what it takes to get there.

[MonzaRacer]

A bunch of the newer 6.0L Powerstroke diesel pulling and drag trucks are using staged, smaller feeding larger turbos.
Honestly if you got around $100k in spare change floating around for development costs, go for it.

[John Wright]

How bout quirting a little No2 to spool up a couple of medium to large turbos rather than all of the double charging?

[Bjkadron]

Well, the G54B is throttle-Body injected, and I have no earthly idea how that would work with twin-charging (or if it's even an issue).

EDIT:Found this in reference to a thread on a Eaton 62 series on a TPI V8. The response is to Another persons post on how the eaton is not designed to have a air/fuel mixture passed through it, and how it may damage the unit over time. He mentioned it's stated on eatons website, but provided no link. No idea if either are correct "Yes, it can be done. Throttle body fuel injection is still fuel injection. It doesn't matter if the throttle is upstream or down stream of the injector. So just place another throttle body on the intake of the supercharger and run your throttle body on the intake manifold at wide open. To keep it simple, use the same throttlebody on the supercharger so you can run the tps sensor and idle speed on the supercharger, you just wont need the injectors. Then pipe the supercharger outlet to the "single point fuel injector". Then youll have to work some sort of fuel enrichemt system, not sure if a rising rate fuel regulator would work to well. You would be better off with the Ford eaton 90 though, from the front of the pulley to the back of the supercharger its 15 1/2 inches long as opposed to the gm eaton 62 wich measures 19 inches long. Shorter is better, the firewall tends to get in the way of progress"

. If it's a major issue, and you want to keep the stock engine, http://www.g54b.com/cgi-bin/yabb2/YaBB.pl has a whole section dedicated to converting from throttle body to Multi-Port Injection. On the conservative side, under $2,000 for this mod. The G54B is a mostly forgotten engine....as far as the aftermarket is concerned. If it's all garage/junkyard tech though, nothing stopping you from being the first. I'd love to see it done.

Not to hop off topic of what your shooting for, but if the G54B is too involved or wallet emptying, take a look at the 4G63 swap. IMHO, seems like the much better option. Comparable to the GM LSX, Honda B-series, Toyota 2JZ, Mazda 13B, or Nissan RB....Tried and true. Twincharging would not be needed, 300HP wont be a problem, and it would be futureproof once you want to turn up the wick. The aftermarket support, compared to the stocker, isn't even comparable....the 4G63 came in the Evolution until 2006. http://www.projectzerog.com/ There are a plethora of different swaps in this chasis, but I'd go for the 4G63 above all. Check out the feature sections of turbomagazine.com, superstreetonline.com, Importtuner.com, Or modified.com to see the numbers the engines are capable of, and what it takes to get there.

I was going to go multipoint then just switch over too a 4g63 after I blow the g54b up. which is a good possibility when goofing around with this stuff. I'm building it for a race where the budget cap is $2010 and ingenuity gets you bonus points. But yeah, the swap is in it's future as they are amazing little engines. Thanks for the link and since I already have the m90 I'm one step ahead!

How bout squirting a little No2 to spool up a couple of medium to large turbos rather than all of the double charging?

That would work great for a drag car... But not for anything else. The scca won't even allow you to use it.

[Ash]

Word, this is one of my favorite cars. I came extremely close to buying one locally that looked like it came off the showroom floor. But when cash was in hand, all of a sudden, the dude selling was doing the waltz around the TITLE....and him not having it on hand. "Just call the DMV in New York...blah blah BS BS...no worries!!!" I power walked away from that purchase.

Your planning on doing both, absolutely bithin'. One thing about this forum that's got the +1 on other forums I've dabbled in is the detailed documentation of builds (hint hint). How many miles does the engine have on it? was it stock or modified when you bought it?

[Procharmo]

Search Youtube for Turbo'ed Mustang GT500's. I think it's a Hellion Kit...Twin turbo's and the OEM blower...Bad Ass....

[79PonchoUK]

I looked into doing this about 5-6 years ago. I'd done turbo charging on a small engine and wanted to get rid of the lag.

There are lots of ways of doing this and most people dream up the most complicated.


The simplest, and probably most effective, is to use a positive displacement charger (roots) which sucks through a big turbo until the turbo spins up, then the turbo blows into the charger. Because the roots blowers are positive displacement, they compress whatever is at the inlet...so if you have a blower that compresses atmospheric pressure to +10psi, you'll get 10psi of boost.

Add a turbo giving +12psi of pressure to the inlet of the roots blower and that will then be compressed to +22psi by the blower.

Actually, the maths aren't quite that simple, but it gives you an idea of how it works. Lag time of the turbo will be greatly reduced because the engine is already kicking out more gas from the exhaust since it's making more power from the blower.




Of course, as I thought more and more about cars, I realised that there is no performance advantage to compound charging, only disadvantages.

By the time you've fitted a turbo, the intercoolers, pipework, a supercharger, bracketery and the pipework for that too....you're heavier than an equivalent power bigger engine, have the weight further forward, costing twice as much and you have 100 things that can go wrong. It works out to be completely pointless.


The only reason you would possibly compound charge is if you just wanted to be techy. Which is fine.

[79PonchoUK]

As for the starion...you can put any type of boost you like through the standard throttle body. It will become a restrictive part of the engine at a fairly early point, probably under the 300bhp mark - you'll need to adjust the fuel to cope with the extra air like anything else...but I can't see that manifold/TB flowing much more. If you're not looking for more power than that then I wouldn't bother changing it to multipoint.
I think people fail to realise that the reason multipoint is used so much now is because it's good for emission. Throttle body injection is often slightly better for power than multipoint....it's just not as accurate (big slow injectors and unmatched ports) so makes the engine produce more HCs. That doesn't cost you any power at all really.


I had a starion until recently...it was the 4g63 version. Gutless low down, lag was rediculous, the best thing for it was an engine swap. lol.

I presume you'd mean a 16v 4g63 swap...better option, I think they need a nice light V8 though personally. The 4cyls just make me sad. :( lol

[Ash]

Yeah, I was talking about the modern DOHC .The SOHC would be alot of work for little gain compared to the Evolution 4g63.


Wouldn't go this rout myself, but cant argue with the numbers.....
turbo 5.7 LS1 Starion : 570 HP/550 LB-FT

http://www.turbomagazine.com/feature...est/index.html

[79PonchoUK]

Cool car, I wouldn't go that route either.

Little point having a turbo on a 570bhp LS1. You can get that sort of power without all the added weight and trouble of the turbo.

The Evo 4g63 could certainly make for a fast starion though. I looked quite a bit into swapping a 6g72 into it from a stealth/3000gt/gto. Now that would make for a quick car.

Easy 350-400bhp, minimal lag and a fairly nice sound track. Got to be a better idea than the 4 banger.