6.5 on 6.2 Turbo no crossover question

[jam]

Hey guys, I've got a head scratcher.

I've seen people run dual turbos... which would mean the engine is powering each turbo off of 4 cylinders right?
I have acquired the 6.5 manifold, turbo, oil tube etc... to perform the upgrade of the relatively low mileage 6.2NA to a turbo motor.

So... would it be crazy to simply leave the driver side manifold and exhaust pipe stock, and close off the 6.5 turbo manifold crossover inlet and let the 4 cylinders on the passenger side spool the turbo?

I'm not trying to make more than 4-7lbs boost (Its an 84 so I believe I have the old heads, though every day is a new surprise). I figure 4-7lbs boost should be "safe"-ish with a 1/8 increase in the fuel screw instead of going for 10 with a 1/4.

Seems like this would eliminate trying to cobble together a custom crossover pipe, and keep the undercarriage fairly clean. Also since the turbo would only be outputting the air of 4 cylinders... I could probably do a 4 to 3" reduction and keep the rough feel of the original exhaust.

But... I could see where maybe a pressure imbalance or volume required to spool might be an issue. Looking for thoughts! Would make the conversion to turbo alot simpler...

 

[Ilikemtb999]

You would have terrible turbo lag as well as an imbalance of the engine. I had a slow spooling turbo with an exhaust leak on my crossover. I couldn't imagine half of the engine trying to spool it.


A crossover really isn't that difficult to make/fab/adapt. I used an aftermarket 6.5 crossover, used the original drivers flange from my old exhaust (maybe 4-5" of it right off the manifold). I cut the crossover in half in the middle to reorient it, trimmed a bit and rewelded it together. That's only two welds. It goes right under the inspection cover of the trans and in front of the trans pan. It doesn't hang low or get anywhere near the front driveshaft.

 

[snowtrac nome]

no as stated lag the twin turbos you speak of are generally compound turbo set ups which draw off full exhaust flow

 

[jam]

Ah that makes sense, oh well... thanks for the info!

 

[ken]

A bigger problem would be that turbos operate from heat/gas expansion, not air flow. You can see this when you add throttle under a load and hear the turbo spool up before the engine responds. Since you would only have half the required heat you would be lucky to make 1 to 3 PSI.

 

[gimpyrobb]

The easiest thing would be to put a 6.5 manifold/turbo system on and use a Heath "turbo master" to keep boost where you want it.