Piston Slap: A Turbocharged "Placenta Previa"?

by Sajeev Mehta

Updated: May 16th, 2014 Published: January 2nd, 2014

Daniel writes:

Hi Sajeev,

I’m a long time reader, first time writer. I have a question which no one seems to know the answer to so I figure you and the B&B can have a go at it. I have a good condition spare turbo laying around from my MR2 turbo before I upgraded. I want to install this into my toyota previa. The problem is the area where the turbo will sit it will be exposed to the elements under the car ( rain, snow, salt) the way the exhaust manifold sits I have no choice. What sort of problems do you think I have in the future with the turbo being exposed like that? I’m in Chicago and this will be driven in winter. And the van is lowered too so the turbo will be pretty close to the ground.

Sajeev answers:

Your problem has very little to do with the turbo’s location. It has to do with the fact that you have a free turbo and now want to build a turbocharged van around it.

Since the factory supercharged Previa has a different engine (2TZFZE) than the base model with a naturally aspirated (2TZ-FE) engine, there’s a lower compression ratio…for starters. Engines designed for boosted applications often have stronger pistons, rods, cranks, unique cylinder heads and sometimes even better oiling/cooling systems. Odds are the Previa’s two engines show a similar disconnect.

And we haven’t even touched on fuel system upgrades, ECU tuning, new exhaust, etc. So sell the turbo on eBay or craigslist.

Your van sounds pretty bad-ass. So if you really love the beast, use the proceeds of the turbo’s sale for a supercharged Previa donor van. Because it is way easier to upgrade when you have the entire conversion kit already assembled in a donor vehicle.

Which is sort of what I’m doing with my Ford Sierra…oh my, perhaps I’ve said too much…

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

#2TZ-FE #2TZFZE #ForcedInduction #ForgedPistons #Previa #Supercharged #Turbo #Turbocharged

Sajeev Mehta

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9 of 16 comments

Corey Lewis on Jan 02, 2014

Previa question: Were any sold here with the vista panel/multi-sunroof option? I know in other places they were, but I don't think I've seen one here.

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- Bball40dtw on Jan 02, 2014
  
  In high school, my friend had a Previa with dual moonroofs. They were good for venting smoke...
  
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- Corey Lewis on Jan 02, 2014
  
  @bball40dtw I always think of the 100 pound car challenge on Top Gear whenever I talk about sunroofs. "I am going to open my ELECTRIC sunshine roof now." As the other two make a face hearing it, ha.
  
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- Bball40dtw on Jan 02, 2014
  
  @Corey Lewis You just want that Audi 80.
  
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- Corey Lewis on Jan 02, 2014
  
  @bball40dtw At that level, I think I'd rather have the Volvo. "A 760, and it's the GLE model!" I would never have bought the 80 with a replacement gear knob, and those fake sport pedals. That indicates trouble to me.
  
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- Bball40dtw on Jan 02, 2014
  
  @bball40dtw I miss the days of going through the "Budget Wheels/Under $500" ads in the Detroit Free Press or Ann Arbor News to see what I was going to drive for four or five months. I guess Craigslist has that demographic covered now, but I liked the suprise of what the car was actually going to look like. I also feel like I have a better chance of getting stabbed via Craigslist.
  
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- Resdhthjlkhhfgvklkjhbkhgyuhb on Jan 02, 2014
  
  @bball40dtw Craigslist photos are small and low-quality, so there are plenty of surprises still.
  
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Rolladan on Jan 02, 2014

Thanks for the reply Sajeev even before the reply I have sold the turbo.... Even mock fitting it the turbo sat 3.5in off the ground effectively making it the lowest point of the van. I have since decided to just drive it until the engine goes (which may be the second coming of Christ) and just do a low mileage jdm swap with a supercharged engine. They're dirt ass cheap anyways since they won't fit in any other car. Best of luck with the Sierra man that's a crazy ride. I would take that shit to the ford dealer for an oil change just to see the reactions you get lol.

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- Bball40dtw on Jan 03, 2014
  
  The Previa engine will never die. If the scrapper that frequents my neighborhood can't kill it, neither can you.
  
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