twin turbos

philip1 · Post by **philip1** » Oct 18, 2007 6:15 PM

I've been rolling an idea around in my empty head. twin Ko3 VW turbos instant spool and they run out of breath at about 5500 on an 1800 so on 1/2 of 3.4 litres they should be good for 6000 or so. I know plumbing would be a nightmare but it would have some WOW factor.

turbodan · Post by **turbodan** » Oct 18, 2007 6:31 PM

Cartech made a twin turbo system BITD. If the novelty factor is worth anything to you thats one thing, but a single turbo is just as practical for all intents and purposes, should you actually end up doing one or the other.

clevertd · Post by **clevertd** » Oct 18, 2007 7:59 PM

http://cgi.ebay.com/ebaymotors/ws/eBayI ... 14512&rd=1

Other than that? Not worth it, except for novelty.

///ARINUTS... · Post by **///ARINUTS...** » Oct 18, 2007 8:28 PM

clevertd wrote:http://cgi.ebay.com/ebaymotors/ws/eBayI ... 14512&rd=1

Other than that? Not worth it, except for novelty.

Is that a true twin turbo set up?

the manifold looks like a 1 piece design. shouldn't 1 turbo be powered by cylinders 1,2,&3 , and the other by 4,5,&6 there should be a divider in the middle or something?

Also, I thought a twin turbo set up spools faster than a single turbo, that flows the same amount of air.

clevertd · Post by **clevertd** » Oct 18, 2007 9:06 PM

A properly sized single turbo will spool just as fast as a twin turbo. Here's a picture of the set-up you described, bimmerforums member e34biturbo.

///ARINUTS... · Post by **///ARINUTS...** » Oct 18, 2007 9:20 PM

clevertd wrote:A properly sized single turbo will spool just as fast as a twin turbo.

That statement CAN be true. However, from my understanding, and it could be wrong, is that when you have 2 turbos with the air flow capacity that equal the air flow capacity of 1 bigger turbo, the 2 smaller ones spool faster.

For example, if I have 2 smaller turbos that flow 50lbs./min. and 1 turbos that flows 100lbs./min. ( 2x50 = 1x100 ) the 2 smaller ones will spool faster and offer the same amount of top end boost.

slave2school · Post by **slave2school** » Oct 18, 2007 9:21 PM

Maybe..but you are dividing the exhaust energy by 2 as well.

///ARINUTS... · Post by **///ARINUTS...** » Oct 18, 2007 9:23 PM

slave2school wrote:Maybe..but you are dividing the exhaust energy by 2 as well.

Thats true, but thats already part of the equation.

Post by **Jeremy** » Oct 18, 2007 10:29 PM

18 psi at 3000 rpm with no boost falloff to the rev limiter isn't fast enough for you? If I wanted it to spool maybe 100 rpm earlier, I'd invest in a double ball bearing center section before I went with twins. The packaging/fitment considerations are considerable, there's only so much room to hang stuff off that side of the motor.

Jeremy

philip1 · Post by **philip1** » Oct 18, 2007 11:28 PM

I don't plan to turbo my 535 I just thought the K03 is about the right size for half my engine.

Kyle in NO · Post by **Kyle in NO** » Oct 18, 2007 11:42 PM

Even with my Motronic setup, my Aqua Man turbo setup spools hella fast. I can easily see boost in the mid-2k rpm range, and its pulling fiercely by 3k. On the highway in 5th gear, 14psi at around 2500 rpm is no problem...

Post by **Jeremy** » Oct 18, 2007 11:53 PM

Kyle in NO wrote:my Aqua Man turbo setup

took me a minute to figure that one out.

Boru · Post by **Boru** » Oct 19, 2007 8:35 AM

Kyle opted for the "complete" water cooled package. It cost a little extra... paying for the "black helicopters" to seed the skies giving birth to Katrina.

Yes, that IS a REAL twin turbo setup in the ebay ad (it has two turbos after all) and it's still available. It is one of 16 ever made and has been modified to fit the E28 chassis. This is the setup that I ran for 40K miles in my 6er.

A sequential twin turbo might have the ability to build boost quicker than a single turbo but a parallel twin system... assuming properly sized turbos for each system, of course.

I did tinker with the idea of adding a valve to isolate one of the turbos until a set boost level was achieved at which point the second turbo would come on line. This would act like a sequential system. I built the valve but was distracted by other stuff and never saw it through.

BerlinThunder · Post by **BerlinThunder** » Oct 19, 2007 12:27 PM

philip1 wrote:I've been rolling an idea around in my empty head. twin Ko3 VW turbos instant spool and they run out of breath at about 5500 on an 1800 so on 1/2 of 3.4 litres they should be good for 6000 or so. I know plumbing would be a nightmare but it would have some WOW factor.

What about this setup ??

http://rides.webshots.com/photo/1129766 ... 0674pyTZSJ

Regards
Alex

George · Post by **George** » Oct 19, 2007 4:52 PM

Sweeney wrote:
Yes, that IS a REAL twin turbo setup in the ebay ad (it has two turbos after all) and it's still available. It is one of 16 ever made and has been modified to fit the E28 chassis. This is the setup that I ran for 40K miles in my 6er.

What CR were you running on that motor?

russc · Post by **russc** » Oct 19, 2007 8:57 PM

Thats the Alpina TT setup in the E34.
Good Luck trying to find that stuff! Those cars come up for sale like once/yr and will cost $25k plus.

See this thread at BF.c for a recent E34 Alpina Bi-Turbo imported to the US and dyno'd(sheet on page 5) at Edge Motorworks.
http://forums.bimmerforums.com/forum/sh ... ght=alpina

RussC

BerlinThunder wrote:
philip1 wrote:I've been rolling an idea around in my empty head. twin Ko3 VW turbos instant spool and they run out of breath at about 5500 on an 1800 so on 1/2 of 3.4 litres they should be good for 6000 or so. I know plumbing would be a nightmare but it would have some WOW factor.
What about this setup ??

http://rides.webshots.com/photo/1129766 ... 0674pyTZSJ

Regards
Alex

clevertd · Post by **clevertd** » Oct 19, 2007 11:46 PM

http://forums.bimmerforums.com/forum/sh ... t=manifold

There's a start to the E34 B10!

BerlinThunder · Post by **BerlinThunder** » Oct 21, 2007 7:15 AM

yes the intake manifold is a good step. I will sell my manifolds and we´re finally there

regards alex

ps. on 1st page of that BF thread there are talking ´bout a guy with shitty shifts

i tried so hard to be fast. And the time was close to 17s not 20s

Matt · Post by **Matt** » Oct 21, 2007 8:38 PM

The reason this is interesting is because K03's are a dime a dozen, and on an itty bitty motor they're at full song before 3000 rpm. I think it's an interesting question.

But, for all of the work involved, I'm not sure it makes much sense. I don't think there are many K03 cars running much over 300hp on pump gas Sure, with 2 of them you'd _love_ 600hp, but that doesn't happen either. Look at the B5 S4.. that's a 2.7L v6 with a pair of K03s...and they're notoroious for failing. I suspect that there's no way an M30B34 flows anywhere near as much as a 5v/cyl modern Audi engine, and I don't think may people can get much more than 400hp out of the S4 on K03s...

I'd look for the highest pump-gas dual-K03 B5 S4 you can find to see if there's any value in doing this. Most people that want more boost go with K04's or GT28s, iirc.

MyE28.com

MyE28.com

twin turbos

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