I was talking to one of my friends today in the shop, and he was talking about how he "Ubercharged" his 89 RS...

This "Ubercharged" setup has a single turbo setup like most turbo applications that runs the air back into the intake... well the side to this set up, is he also slapped a roots suppercharger onto it wich blew even more boost thru it.... Has anyone seen anything or heard of anything like this before and if so have you done it????

Maybe??? I haven't seen the engine for myself I'll see it next week(suposivly). Anyone think he's making this **** up?

 

It can and has been done. But by precious few people. And never for cheap money. Certainly not by yours truly. In theory the roots blower supplies the instant boost to get the motor making good power from the instant the pedal is matted. This also creates a lot of exhaust gas which quickly spools up the turbos and then the REAL fun begins.

Building stuff like this for either street or racing is nuts unless you really got a weird itch. I just can't imagine it's cost effective vs. a well designed twin turbo system. And it's certainly not lacking in complexity, that's for sure.

 

Id love to see a photo of someone who has actually done this. Take a camera with you and snap some photos for us.

Interesting.

 

It would be easy to rear mount turbo a supercharged car..

I think you would reach the blocks limit really fast... wear as you can just turn the turbo up for itself.

 

Well the supercharger is used for the low end application... then when it hits a certain speed\RPM he has a valve that turns the supercharger off and lets his turbo goto work on the top end:hail:

 

If it's root type shouldn't it be under pressure all the time since the teflon rotors are air tight?

I thought of that idea acouple months back... using a roots for off line pull (make a lot of tq right away) then an ati for top end. Just spin the roots boost slow and lets the ati do all the work pretty much on top end. Then I realized I only make 100 bucks a week (student, 19 class hours, 20 work hours weekly) so I won't ever probably even get a ATI. hehe

 

I have the pictures... now all I ahve to do is find a way to get them on my comp... No scanner

 

Ive been seriously considering doing this setup in my build up. i had posted a thread on here a few weeks ago about it, and it seemed to get shot down pretty quickly. if you have pictures, and maybe some numbers, that would be really cool, and would help me decide where to go with my setup.

 

don't worry, I still think it's a stupid thing to do to a gas engine...

 

i wonder how hot the air is going to be after its compressed TWICE!?


esp since the 2nd time will be horrible inefficent...



and what will the point be? unless you want 65PSI of boost ramming into the motor, you will be spewing off half the air out a giant BOV......



you would still have the drag of the supercharger that you arnt using too...?




i dont get it....?

 

I don't think it would hinder the boost since the contents are already under pressure when it hits the slower turning roots. And it shouldn't build up any more pressure than before. You're right about the dual drag put on the motor (roots and centifugal both turning). It wouldn't probably be too pratical, but it would look different that's for sure.

 

umm.. the roots blower would re compress the air even more...


it takes in air in X amount of space, and shoves it into a smaller space.....Y


so if X was already under 12PSI, Y might end up being the equivlent of 20PSI or higher......


unless of course the blower is waaay undersized for the app...

in that case, the blower is nothing more then a huge restriction..... right?

 

Dunno what engine this is but..... twin turbo + roots setup.

 

hmm... now that way might work, since the turbos boost isnt going thru the blower...





still stupid idea IMO though.


edit:

before someone says it, yes it probly helps that tiny motor have more TQ down low, and the turbo helps up high.


i still think thats stupid.

i also think putting that much money into a 4 cyl is stupid.

 

OK, just because someone has done something before does not make it a good idea…

In this case, what’s the point? Unless there’s some kind of check valve in the system if the roots builds any boost before the turbos you’ll just force it out the turbos making it harder for them to spool and get past their surge point. You’ll only get as much boost as the what the turbo or blower making the least amount makes.

 

bugatti makes a quad turbo supercharged beast.

but the car it goes in has ursurped the McLaren F1 and its ugly as hell.

but anyways.

i dont think i could bother putting that much work into an engine. Especially a torque-monster 350. A 4 cyl just wouldn't be worth it.

but you could probably break the rear end lose at 80 and scratch into 4th...

 

i just wanted to add my 2 cents.. for anyone seriously interested in doing this i'd recoment a centrifugal and turbo... the centrifugal will make low end power, and help spool the turbo to make high end, but dont feed them into eachother, run the intercooler pipes the same as you would a twin turbo setup. i personally still say twin turbo would be better, in drag racing anyways, cause the turbos usually will spool by 4000 rpms, and you can just get a stall and launch on boost, so you dont need a whole lot of bottem end

 

I have seen that kind of setup (turbo feeding roots super) on several deisel engines in miltary trucks. It does work quite well. Some of the older trucks have the same engine minus the turbo and it is such a dog compared to the truck that has the supercharger and turbo.

 

i could see a turbo feeding in and a roots feeding OUT to the turbo... hrm..

 

no, they have the turbo(s) on feeding the engine and the roots blower scavenging the exhaust. Those are 2 stroke diesels

 

umm. a positive displacement blower will push alot more air down low then a centrifugal.....

 

well if you have the money and like to complicate things why not. The way I look at it is why not just spend the blower money on a better Turbo set up. Also the computer must be confused having all sorts of air from lots of locations coming in.

 

umm, yes on the better turbo setup


no on the computer being "confused"


it only sees the air coming into the throttle body (maf) or the pressure in the intake (speed density)

it couldnt care less how the air gets there.

 

I THINK that's a Skyline motor but don't quote me.

As for as the discussion...yeah it'd be cool for the "WOW" factor but it's overkill. There is no reason you can't run a conventional blower or a turbo setup and make PLENTY enough power.

If you want to do it you better get an intercooler the size of Texas like the one in the pic...

20+ pounds of boost and extreme heat=baaaaad things happen

 

Yeah, that's a Skyline engine. RB26DETT, it's an inline 6, 2.6L. MR2's had a twincharger kit make by HKS at one time. The kits were discontinued a long time ago, though. Search for twincharged mr2 on google. I can't find any pics, but they list power and track times.