Recently started performance mods on '88 760 Turbo. In the process I've come across a Mitsubishi Turbo unit from another junked 760 Turbo in working condition. Was rebulilding it as a spare unit for when my stock one goes. Got to thinking about what it would take to set up a twin turbo setup (if it could be done at all) on the B230FT engine. Anyone have any ideas about a possible setup (mods to the intake manifold, how to drive the secondary turbo unit, mods to the intercooler etc.) Any ideas or suggestions would be appreciated!

RAS

Two Turbos and Dream

for high boost apps. I think you'll find the #1 conrod will shatter first, and quickly.

Note that the twin turbo 960 on prev post was rebuilt with lower compression pistons!! 380hp out of 3liters is reasonable, and the job looks pretty well done.

But I bet he spent a LOT more on that twin turbo setup including the engine rebuild than a 5.7 or 6.0 L (or a 400hp 5.0L Ford V8) would cost.

Also, don't forget the rear axle will spin the right wheel like crazy w/o a locker on it. Figure $400 or so for a powertrax locking diff...supposedly they can be installed w/o pulling the ring gear. Summit racing or JEGS, get one for a DANA 30 series diff.

Hi,

In another life, I worked on diesel engines tuning them for maximum horsepower for turbocharging. I have, but might have trouble finding, books on turbocharging theory and staging turbochagers. Tractor pullers stage turbo chargers to build more boost. Most NTPA open class diesels now run three turbos in series. The turbos are three different sizes. The idea is to build higher boost with each stage, compressing the air tighter and tighter. The air then goes to the air to air heat exchanger then into the intake manifold. High performance diesels are now building over 100 lbs of boost. Alchohol etc is pumped directly into the intake and the run or pull is ort of a run-away condition. They are not worried about lag time. The drivers slowly build boost..and turn on various fuel and alchohol sources as the clutch is loaded and rpms climb. They have outlawed most computer controled fuel devices leaving the driver to watch rpm, boost, and exhaust temperature gauges as he watches many many gauges. The whole pull is over in 15 or 20 seconds.

What does this have to do with volvo turbocharging. Lots. The turbocharging of a spark fired engine is much more complicated because of the balnancing of boost and spark not. It is my opinion that you are not looking for more boost from the mitsubishi, but boost over more rpms. To do this, you will need tighter waste gates or waste gate controlers. Or you will need tighter snails,(scrolls) which control the turbocharger rpm in relation to the amount of exaust gas, or if you twin turbo, you would want two small turbo chargers..not two full size turbo chargers. I could be full of crap because I do not know how much exhaust the mitsubishi now diverts at low rpm. My Guess is that the waste gate is not diverting any till the rpms build. I also have to smile and wonder if you realize the nightmare of building the mounts and plumbing required for multiple turbo applications.

Good luck,

I do have my 740 turbo project on the road. I love listening to my turbo spool up. There is a turbo shop expert in my area that is also familiar with bosch injection. I am reluctant to post thier name on the web, but might give it out with a personal email request.

I hope I have not offended any of your volvo experts with my ramblings.

Pat

Hmmmmmmmmmmmmm..... It's doable but likely too much effort for the benefit. The reason for twin turbos is usually elimination of lag time. However a large intercooler sutup like the Volvo is already a setback in the lag time fight. A pair of small turbos to do the job of one big one is the key here. It is possible to build a wastegate setup and quick spooling turbo to get the same results though. That is something I have tried and had good sucess with. Don't forget two turbos means two of all the related plumbing. Air, boost, exhaust, coolant, oil feed, and oil drain all must be doubled up. The amount of fabrication would be challenging even to the boys and girls at NASA. A nice supercharger setup, now that keeps me awake at night.

ever seen a 200/700 series with a working supercharger set up? Any parts/kits available?

I've got a N/A 240DL i'd love to supercharge... My next weekend of suspension upgrades is really going to beg for more HP ;)

-Nate

Here's a little motivation: Twin Turbo 960.

If someone can put two turbos on a non-turbo motor, I'm sure you can put two turbos on an engine meant for one.

Good luck.

I'm not sure what it would take, but check out the setup on the last gen. Toyota Supra. It has the twin sequential turbos on it. The same method would apply to the 760.