Twin charged vs Single

[dsm4fox]

This is going in the general Field Because its more of a general opinion vs a fact.
So Ive seen ALOT of twin charging going on! Everything from 3 cyl subaru engines to v8 mustang KITS... We have a few members of our community that have this idea down like ray peters and his 1g. A few of us have compound turbo's. Even seen a nicely made up custom twin turbo manifold for an evo.. So here is my question. Would you twin charge? how? and why?? I personally have been considering adapting the use of a STS rear turbo with the current turbo system. And basically use it like a compound turbo. But i want all opinions and whys. Not just "35r Turbo because its easy" Would you use a centrifigal supercharger? Twin screw? single turbo? I personally like this topic because i love the rapid power of a smaller turbo but hate the drop off there after ...

 

[crand]

im running a big single on my car right now and think it is how i would run just about any car, even guys with the 2jz like to go to a single...
on the other hand, i have compounds on my cummins and love it!!! definatly for a different style of driving and different purpose, that said, i still think single is best...

 

[g4ebguy90]

I think I would rather have Single sequential . Uses pretty much 2 compressor wheels in one wheel casting.

Another alternative more up your alley is the LST low speed turbo. Gets higher boost pressure from lower shaft speeds.
I have no clue on application to the 4g though.

But I think its a better idea then plumping to turbos together. Just have it internally plumbed with the benefits of 2 compressor wheels.

 

[Riceburning101]

I vote Single Sequential Variable Geometry turbo. A lot of the new diesels run them and like g4ebguy90 said its like two in one. DualBoost Single Sequential Turbocharger I am ashamed to post something about a fix or repair daily on here but this is a good explanation and diagram.

 

[dsm4fox]

im running a big single on my car right now and think it is how i would run just about any car, even guys with the 2jz like to go to a single...
on the other hand, i have compounds on my cummins and love it!!! definatly for a different style of driving and different purpose, that said, i still think single is best...

I would agree that they are for different types of driving for sure. I cant see a daily driven car with out the rapid spool.. or a drag car with out the total top end. Here is a thought. Would you ever consider switching to a really heavy volume centrifigal supercharger vs the larger turbo due to the SC being fully top end.. I have always wondered for drag racing the benefits of going from a turbo system to a SC on our cars that way peak power is always at or close to red line... Big down fall is max rpm limits there on the SC i suppose

I think I would rather have Single sequential . Uses pretty much 2 compressor wheels in one wheel casting.

Another alternative more up your alley is the LST low speed turbo. Gets higher boost pressure from lower shaft speeds.
I have no clue on application to the 4g though.

But I think its a better idea then plumping to turbos together. Just have it internally plumbed with the benefits of 2 compressor wheels.

The rx7 twin turbo has a system kinda close to this.. I guess its more like a twin scroll with 2 compressors.. if i remember correct it has 2 diff sized turbos basically merged in the exhaust housing facing away from each othere... I would rather have the 2jz system but its complicated with all the valves to keep it running on one turbo then switching to both.. I know thats why alot of the 2jz swap guys go to single turbo vs stock twins due to the complexity of the stock turbo system and how ingages from one to both.. I bet toyota had fun R&D'ing that system

 

[canada4g63]

Single, easyer to maintain one turbo, more room in the engine bay. I think on the MR2's usual run a smaller blower and turbo for up top.

 

[Cirus_93TSI]

I would think that the bigger downfall would be our 4 cylinder engine having to spin the belt for the super charger. In most 4 cylinder cars you can feel the power drop just by the a/c compressor being turned on, i would think having to spin up a large super charger would be much worse. I mean i could be wrong, but considering how a supercharged honda feels, i would think it would be similar. Basically your losing so much power having to spin the SC that you dont gain as much as you would want or expect.

 

[dsm4fox]

I vote Single Sequential Variable Geometry turbo. A lot of the new diesels run them and like g4ebguy90 said its like two in one. DualBoost Single Sequential Turbocharger I am ashamed to post something about a fix or repair daily on here but this is a good explanation and diagram.

THAT IS VERY VERY INTERESTING It's like a twin scroll turbo on steroids... HAHA I think it would have a similar feel to the compound turbos. But i cant help but feel like it would sacrafice a little of the total low end/top end gain from the compound. It seems to me it would be more of a meet in the middle with more top end due to only one wastegate.. They work together in that. and are way more reliant on each other i would say.. where as the compound turbos feed past one another... But this system would have alot less complexity for sure and wouldnt need all the careful balancing between turbos.. This is a very very interesting idea I LOVE it..
Thank you for posting that!!
I think we could do wayyyyyyyyy more with turbo's (like this example) then what we have been stuck doing for the last 2 decades

 

[1990AWD]

Toyota's 2JZ-GTE and Nissan's RB26ETT both had parallel turbos, and guys go to single for the simplicity plus the turbos are really small and can't make much power over stock.

Mazda RX-7 had two turbos in sequential, using one small turbo for low rpm and then switching to the larger turbo for higher rpms.

The turbo on Ford's new 6.7L turbodiesel simply has two compressor wheels on one shaft. That way they could make it like a twin turbo on one shaft. The turbine is twin scroll with VGT so there is virtually no turbo lag.

Fleece performance makes a stand alone controller for the Holset VGT turbos so you can put one on almost any application.

Ulitmate performance would be a supercharger and a Holset VGT on a stroker 4G63 but good luck fitting that in the engine bay.

 

[dsm4fox]

Single, easyer to maintain one turbo, more room in the engine bay. I think on the MR2's usual run a smaller blower and turbo for up top.

Yes i think you are right I have seen upgrade kits for them online if i remember correctly.
I think using a twin screw design with a decent turbo would be good for a road coarse car! The way the twin screw changes the power curve is almost like having a stroker on boost. The new mustang 5.0L has a kit out called i think the "hell raiser kit" where it uses twin turbos and a twin screw I bet that would = the death of traction for those cars

Toyota's 2JZ-GTE and Nissan's RB26ETT both had parallel turbos, and guys go to single for the simplicity plus the turbos are really small and can't make much power over stock.

Mazda RX-7 had two turbos in sequential, using one small turbo for low rpm and then switching to the larger turbo for higher rpms.

The turbo on Ford's new 6.7L turbodiesel simply has two compressor wheels on one shaft. That way they could make it like a twin turbo on one shaft. The turbine is twin scroll with VGT so there is virtually no turbo lag.

Fleece performance makes a stand alone controller for the Holset VGT turbos so you can put one on almost any application.

Ulitmate performance would be a supercharger and a Holset VGT on a stroker 4G63 but good luck fitting that in the engine bay.

The 2jzgte uses its turbos different than the rb26 though. It has several inline valves in the exhaust and the intake ect to go from one turbo into 2 depending on several different sensor inputs.. it literally channels all the exhaust into one then switches to both around 4k depending on throttle ect

The rb26 turbos are very small almost as bad as the stock 9b's on the vr4 3s cars! Now there is a turbo system designed way to small for the volumetric demands of the engine IMO

I would think that the bigger downfall would be our 4 cylinder engine having to spin the belt for the super charger. In most 4 cylinder cars you can feel the power drop just by the a/c compressor being turned on, i would think having to spin up a large super charger would be much worse. I mean i could be wrong, but considering how a supercharged honda feels, i would think it would be similar. Basically your losing so much power having to spin the SC that you dont gain as much as you would want or expect.

Im not entirely sure how much it would drop power at idle on our cars.. If it was a stricktly drag car though.. I think you could really benefit from it to a given point.. then i think after that it would be useless.. Given you are limited by rpm. Turbo is more versital for sure!
Interesting side note has anyone seen the dual engine video floating around of the 1g..... WTH ... wow is about all i can say to that...

Twin Engine 800hp Eagle Talon - 4.6L Twin Turbo! - YouTube
... Seriously..... Talk about custom work... Im not sure if this is one thing i would EVER attempt.. But its deff thinking outside the box... This counts as twin charging a car haha but not an engine

 

[1990AWD]

The 2jzgte uses its turbos different than the rb26 though. It has several inline valves in the exhaust and the intake ect to go from one turbo into 2 depending on several different sensor inputs.. it literally channels all the exhaust into one then switches to both around 4k depending on throttle ect

The rb26 turbos are very small almost as bad as the stock 9b's on the vr4 3s cars! Now there is a turbo system designed way to small for the volumetric demands of the engine IMO

My bad, the 1JZ-GTE was parallel, 2JZ-GTE is the sequential. But anywho...

You also have to remember that when having two tiny turbos, you also have a very small displacement for each. My 3KGT VR4 has the little 9bs, but it also only has 1.5L to spool each. Granted they can and do benefit hugely from turbo upgrades though.

Look up the customized Lotus Elise in California, he took the 1.8L Toyota engine and added a large Garrett turbo (GT30 or GT35 I can't remember). He hated the spool and added a supercharger and brought the car up to I think 680whp and had zero turbo lag and a huge powerband.

 

[dsm4fox]

Look up the customized Lotus Elise in California, he took the 1.8L Toyota engine and added a large Garrett turbo (GT30 or GT35 I can't remember). He hated the spool and added a supercharger and brought the car up to I think 680whp and had zero turbo lag and a huge powerband.

SWEET JEBUZ... 680whp in a lotus..... Thats like ray peters 1g.. Idk if you've seen his but he is running an eaton twin screw and something crazy like a 35r and a 2.3l... crazy power

 

[BoostKrazy]

I would agree that they are for different types of driving for sure. I cant see a daily driven car with out the rapid spool.. or a drag car with out the total top end. Here is a thought. Would you ever consider switching to a really heavy volume centrifigal supercharger vs the larger turbo due to the SC being fully top end.. I have always wondered for drag racing the benefits of going from a turbo system to a SC on our cars that way peak power is always at or close to red line... Big down fall is max rpm limits there on the SC i suppose

Actually superchargers tend to "fall off" and lose 60% (i believe) of efficiency by red line.. on the other hand, turbo's do not, but they have the "lagg factor" and SC's do not... that being said, SC's are ran on a pulley which take hp to turn (like an ac compressor).. so imo, BIG fat single snail

SWEET JEBUZ... 680whp in a lotus..... Thats like ray peters 1g.. Idk if you've seen his but he is running an eaton twin screw and something crazy like a 35r and a 2.3l... crazy power

You think 680 in a lotus is nuts? Look up the hennesey venom gt, retails for 700k, hennesey somehow fit a built ls9 (zr1 engine) in a lotus exige making a 1,200 whp 2,000 lbs go-go-cart.

 

[dsm4fox]

Actually superchargers tend to "fall off" and lose 60% (i believe) of efficiency by red line.. on the other hand, turbo's do not, but they have the "lagg factor" and SC's do not... that being said, SC's are ran on a pulley which take hp to turn (like an ac compressor).. so imo, BIG fat single snail

Which type of charger are you talking about is the question? because roots blowers tend to have low as dirt efficency. and fall off like you said. twin screw S.C.'ers have more efficency, more reliable in mid range. and Centrifigals as long as the engine demands dont over power the chargers output of air flow they hold efficency till almost peak rpm.. Roots blowers (designed after a blower system used for like old mining shafts ) are almost crap to todays standards.. The twin screw is like it but actually does a better job of pressurizing the air. Centrifigals are hit n miss depending on vendor and sizing for the car.. If you buy the "kit" or size they recommend like say if you use the import version of the vortech line for our cars which i think is the v5... You would be pissing power away.. If you used a more agressive sized charger for something alot bigger, considering our engines are designed for this kinda abuse and builds. You could push a crap load of CFM in a smaller amount of psi. The charger will never drop below the engines volumetric demands.
And a common miss conception is that turbo's are free energy.. It is said that not only a bad designed manifold or cast mani can cause unfelt power loss at high P/R from bad back pressure from one exhaust vain to another while the others valves are open.. blowing exhaust back in a different cylinder. and thermal impact on the engine overall.. Realistically The gain on the SC side is this...
RPM doesnt change.. So using a larger s.c. you get more CFM at lower psi. For example.. (not to be quoted with actual numbers but more for an idea) Say you use a 35r and run 22psi and get 800cfm... You can select a supercharger to push over 1000cfm at 14psi and your rpm level doesnt change.

Too many options... To little time

 

[1990AWD]

SWEET JEBUZ... 680whp in a lotus..... Thats like ray peters 1g.. Idk if you've seen his but he is running an eaton twin screw and something crazy like a 35r and a 2.3l... crazy power

World's Fastest Lotus?

 

[boost97gst]

^^ That was on tv not long ago. I about shit when they said the power to weight ratio. Cant remember exactly but its one of the fastest/quickest cars anywhere. Like F1 car fast...

 

[dsm4fox]

World's Fastest Lotus?

Very nice I love it!!

 

[dsm4fox]

Ok guys so here is what i have learned about twin charging so far...
If you use a Supercharger like an Eaton twin screw, with say a turbo. This type of supercharge is estimated to consume around 150hp near red line on a 500hp engine where it should be making 650hp..... Centrifigal chargers use considerably less power but still suck it up to make it.

Compound turbo's have been designed out in 2 different ways on gasoline engines. The first way is to use the 2 turbo's together. The larger turbo when it kicks in basically acts like an ambient pressure increaser. While the smaller turbo does all the work by taking a inlet ratio of say 2:1 and multiplying it by 2:1 or so on.. Instead of feeding off of a 1:1 ratio of the inlet.
Or there is the method i think is a really good and simple idea. You use the two turbos together as dual "single" turbo lay outs.. Say you have a clipped e316g with like a 44mm external w.g. and set it to 18 psi. And then used a 3076r or 35r and set its boost level to say 22 psi. Essentially what happens in theory is the first turbo spools up like normal. And as the 2nd one begins to spool pressure into it. It takes less effort to make the boost level needed until finally the turbo's gate is fully open when the larger turbo passes the boost level the smaller one sits at. It basically takes the first one away from the system and begins running like a 35r or what ever you have. The smaller turbo has to be within a certian % of size difference from turbo to turbo IMO keeping in mind the compressor HOUSING not wheel.. as a restriction for the larger turbo in volume to try and flow past. Which really isnt that big of a deal if you think about it this way.. the first turbo wont be fully dead in the water but more or less spinning free in the wind so to speak and keeping air flowing fairly well around its compressor. Only thing really is making sure the exhaust side can keep up with the added HP worth of flow out. and that the wastegate is LARGE enough to actually de activate the first turbo. Also i think having a very good Tubular manifold in this case will really help the design given that large pres ratios already make cast manifolds and log types basically allow exhaust to flow backwards... You wouldnt want any risk with added back pressure of say 500hp worth of volume going into a 16g's housing. Or from having an extra turbo in the mix also... Back pressure and flow capacity seem to be the biggest issue with config compound turbos from other peoples projects

 

[LandSpeed-DSM]

Some of that is on point, regarding the staged-turbocharger setup, but there is much that isn't fully accurate in that post.

Please use formatting/breaks.. that wall 'o text is hell on the eyes.

 

[mitsurage]

4g63 - Big single.
V8 - Really big twins.

 

[dsm4fox]

Some of that is on point, regarding the staged-turbocharger setup, but there is much that isn't fully accurate in that post.

Please use formatting/breaks.. that wall 'o text is hell on the eyes.

sorry i will keep that in mind for the future here

 

[dsm4fox]

I vote Single Sequential Variable Geometry turbo. A lot of the new diesels run them and like g4ebguy90 said its like two in one. DualBoost Single Sequential Turbocharger I am ashamed to post something about a fix or repair daily on here but this is a good explanation and diagram.

Ok so the Variable geometry turbo turns out to have insanely high exhaust gas temps and some issues in that area.. but this got me digging deeper into turbo methodys being tried right now. And Borg warner has made and is using a dual turbo NON compound system (not that new of an idea really) where it works just like a compound, till boost levels open an actuated valve in the INTAKE side before the smaller turbo, bypassing its compressor housing..

I guess this is the method id be most interested in.
First turbo like stock spool. Larger turbo begins to surpass that one. Opens the wastegate for the first one. as boost builds past a given point the valve on the compressor side opens allowing total free float of the high pres turbo. allowing boost to pretty much take the path of less resistance..

I can see this giving long life to this set up, given a surge port on the larger one and the 1st one almost being bypassed completely..

ON a side note has anyone seen any of the research being done by honeywell on AIR bearings??? Very interesting stuff there

 

[zedicus]

you want something different?

Leaf Blower Supercharger - Hot Rod Magazine

 

[schalk35]

^ haha I was waiting for someone to put this up. Helarious!

 

[renovatdkitchen]

I wonder if it would work if the fins inside a turbo could rotate, sort of like how prop planes can go into reverse. Would it reduce lag if the fins were all flat at slow speeds, and then gradually developed a steeper angle as the speed of the shaft increases?