Twin turbo.....which ones???

mrbeige wrote:

dirtytorque wrote:I guess the (cost/gain)* (agro) factor is unappealing but it is a much better engine configuration.Cold air at front,hot air coming out at back.shorter pipe work...

If it wasn't for that pesky alternator on the g60...

Can't you mount the alternator underneath the charger? Maybe where the power steering pump is and then run an electric one instead?

Chris runs a g60 intercooler with the u-type bend that runs underneath the charger so its a non option as he doesn't want to loose that config,and i guess there would be other changes as well.
It would still interest me tbh if i wasn't going 16v. advocate.The gains would be more subtle I think.

PAS pump is at sump level so don't think an alternator would like living down there but yeah it's an option.of course. Your right dirtytorque but how many people do a 16vG60 just to remove heatsoak?

I know I could have an exhaust turbine driven alternator!

ctwg60 wrote:PAS pump is at sump level so don't think an alternator would like living down there but yeah it's an option.of course. Your right dirtytorque but how many people do a 16vG60 just to remove heatsoak?

well I guess I'll have to dream up some other way to get you to spend your money.

ctwg60 wrote:
Yep, and I read in a book that they ran a shorter rod as well lowering the rod to crank ratio but I've never been able to substantiate that.

The 2 litre xflow runs a longer stroke same rod length, same result though on the rod ratio. Just a slightly different percentage.

This post wondered way off topic .
I think a twin turbo 16v engine woulod be interesting.
This might be the only thing that would tempt me into going through the pain of another build.
Two small to medium t'bo's on a 16v engine would present some interesting design challenges.
I think the torque curve would look alot different to a single bot unit ,even it the final power figures were similar!!???

I love the idea, I think I'll go single turbo with a spacer on the standard engine on Gooney, then when I finally build up the 2E bottom end, go down the twin turbot route. The manifold will be interesting, that's for sure

Stu, I can send you the enthalpy and isentropic efficiency equations which should help you see which turbos will work well from a thermodynamic point of view? I've been doing that kind of thing recently - work out internal system energy between compressor and turbine and you can convert it into power in kW etc.

from a laymans POV, I hear the disco potato works well on a 16v! lol.

boost panda wrote:Stu, I can send you the enthalpy and isentropic efficiency equations which should help you see which turbos will work well from a thermodynamic point of view? I've been doing that kind of thing recently - work out internal system energy between compressor and turbine and you can convert it into power in kW etc.

from a laymans POV, I hear the disco potato works well on a 16v! lol.

Aye the GT28RS seems to be 'liked', but then where is the fun in that

I'd be interested to see any mathematics that my help to find suitable turbots to use

mrbeige wrote:

boost panda wrote:Stu, I can send you the enthalpy and isentropic efficiency equations which should help you see which turbos will work well from a thermodynamic point of view? I've been doing that kind of thing recently - work out internal system energy between compressor and turbine and you can convert it into power in kW etc.

from a laymans POV, I hear the disco potato works well on a 16v! lol.

Aye the GT28RS seems to be 'liked', but then where is the fun in that

I'd be interested to see any mathematics that my help to find suitable turbots to use

yeah,but don't go nuts.

And try and add some generalizations
Oh and then come and build it too.
I'll get my coat.

Ok, so been thinking a little more about the twin turbot thing and was wondering what peoples thoughts were on which turbochargers to go for. I was thinking something along the lines of the turbochargers fitted to Diahatsu Charade or Renault 5 GT Turbo???

An overwhelming response Everyone must be out enjoying the sun

I know very little about twin turbos. JNL is your man. I seem to remember him mentioning a couple of tiddlers with 0.48 exhaust ARs?

How about a couple of K03S turbos from a late Golf 4 or current Polo GTI?

Or what about a Turbo plus Eaton charger? Was speaking to a chap recently (he has an Eaton M90 on his VR6) and he was saying spraying fuel onto the compressors super chills them and therefore the boost charge, but long term metallurgy implications aren't known..... but I was thinking if you had a big turbo feeding a Positive displacement charger, the boost from the super will keep it on song until the turbo spools up and when the turbo is on boost, the S/C will compress the boosted air still further, so best of both worlds? Plus that compressor chilling..... could be a good project?

ROFL! Indeed, I think the sun is definitely very inviting!

Would the K03S be too big to effectively run on two cylinders (1 litre)? I would have thought the buggers would never spool, or at least not until two high an rpm to make it very 'driveable'??

I did think about the Eaton/Turbo combo, the idea obviously sparked off by the current 1.4 twin charged VW engine, but thought that the control of the system might well be too complex for a 'first' project.

spraying fuel onto the compressor blades sounds interesting though, but could you get the same/better effect with the likes of Meth/H20?

kevhaywire wrote:Was speaking to a chap recently (he has an Eaton M90 on his VR6)

That wasn't LarkinBoy off VR6OC was it? I asked him if he'd join up here but he never replied to my PM If we are singing from the same hymn-sheet, Kev, ask him next time you speak to him...

That's where my knowledge runs out As a guess, although the effective displacement per turbo is only 1 litre, but as there's 2 of them, their effect is twice that of 1 turbo on a 1 litre 4 cyl engine, if that makes sense?! LOL! I hear what you're saying though, 2 turbos designed for a 1 litre engine (i.e. Charde Gtti) should work well. There's also Smart car turbos too, only 600cc to deal with, so the spool should be good. Not sure about the top end restrictions though.

I don't think a turbo plus S/C would be that complicated tbh. It probably would be with a Rotrex type centrifugal S/C, but with a Heaton, you can just map against the pressure the manifold sees and let physics take it's course with the 2 chargers My illogical brain is telling me that off turbo boost, the PD charger will help pull air through the turbo and consequently reduce lag and when the turbo comes on boost, the Heaton just has to ram it all in. What I don't know about is whether the S/C's scrolls would present a huge restriction to the turbo, or whether the scolls would just say, bring it on!

Can't inject meth onto the scrolls, it would eat the alloy. Bioethanol might work though as it's a different kind of ethanol.

Yeah I think it could be Larkinboy yeah, I know him as Tom. He does Stealth's fabrication work and he's fabbed up a few things for me to a very high standard. The fact he understands VR6s really helps!
I don't think he goes on the forum a lot but he knows a lot of useful stuff!

mrbeige wrote: did think about the Eaton/Turbo combo, the idea obviously sparked off by the current 1.4 twin charged VW engine, but thought that the control of the system might well be too complex for a 'first' project.

What car is this in? How do you find the engine? Thinking of getting a passat estate 1.4 twin early next year.

MK5 Golf GT TSi
Scirocco GT TSi