Turbo 218 Slightly OT

[mach0415]

I am getting ready to build a 218. My intent is to boost, using a turbo. I am considering using the stock exhaust manifold and stock intake, but the plan is to port and polish to open it up some. I can force feed the Stromberg, with some jetting adjustments, or I could pull through a Holley 2 barrel. I have seen TurboStude, and am pretty inspired to something a little different from the same ole upgrades to a Mopar flat six.

I will run 5-8 psi, but would like some input/thoughts on which turbo would be the best size/fit. I am aware that diesel turbos are very different from gasoline turbos. My first thought was to use the classic KKK K26 from a Mercedes Benz 5 cylinder 3.0L TD because they are cheap and easy to find at a P-n-P salvage yard , but do not know if it will boost/spool the same as a gas burner. Perhaps a Volvo turbo would be a better match?

Let me know your thoughts

Mark in NC

[moose]

I've thought about this before too, and Saab turbos are also very plentiful. The 9000's are maybe a good choice, they are "older" now.

[Don Coatney]

What carburetor do you plan to use with your turbo?

[52b3b Joe]

I think those Saabs have Garrett t-25s and are also common on the eclipses. I just bought one for $20 used. The only problem with those is that they might be a little too small for the mopar sixes, but with low boost, you would probably be ok. They don't really recommend anything over roughly 150 cubic inches or 2.5l for those (probably for HIGH performance applications), but you need to do the research to see how much calculated air the engine needs and how much air the turbo will supply. The worst part of turbo I think, will be running the coolant lines, and if you keep low boost (like 5-7 psi) they say you don't really need an inter-cooler but I would still try to put on one. Also with the turbo, you would probably want to keep the stock cam and try not to bump up the compression a whole lot. I'm no expert at all on turbos, but that's just my understanding (a lot of my friends are into superchargers and turbos). I'm into Corvairs, and I know all the turbo ones use the low horsepower cams and low compression heads. And my good friends dad (has a very modified RX-7) always says: "you don't want very high compression with a turbo". I'm just saying what I've been told, as I said I'm no expert. I say GO FOR IT!!!

[Frank Elder]

You are correct Sir!:)A lumpy aggressive cam and Hi-squeeze compression would actually hurt your HP.

[greg g]

most modern turbo engines run between 8 and 9.5 to one CR. As the 218 is in the 6.7 to 7 neighbor hood, the head can still be massaged. this will give the motor a bit more umph before the turbo spools up. The problem I see with modern engines i tha ost of them are designed to make boost in the upper RPM ranges. Not where your 213 wants to be making power. So I might suggest you might want look at a turbo from a diesel VW or similar, even some of the Mitsubishi or Nissan small diesel delivery trucks. their working RPM, and boost curves are probably more in line with the needs of the flattie's needs. It is also my belief the these might be waste gated more closely to the 7 lb region. Most of the car deals are made to be in the 9 to 11 psi range.

I would think you don't want a set up that needs to spool up to 3000 rpm before it begins to build boost, if your are oly goig to rev it to 4000.

These truck engines are in the 3.7 to 4.1 displacement range making 130 to 150 HP. and though they are 4 cylinders they probably fit your needs better.

If you are going to go that way might you want to look at something like throttle body FI from something like a GMC V6.

[52b3b Joe]

most modern turbo engines run between 8 and 9.5 to one CR. As the 218 is in the 6.7 to 7 neighbor hood, the head can still be massaged. this will give the motor a bit more umph before the turbo spools up. The problem I see with modern engines i tha ost of them are designed to make boost in the upper RPM ranges. Not where your 213 wants to be making power. So I might suggest you might want look at a turbo from a diesel VW or similar, even some of the Mitsubishi or Nissan small diesel delivery trucks. their working RPM, and boost curves are probably more in line with the needs of the flattie's needs. It is also my belief the these might be waste gated more closely to the 7 lb region. Most of the car deals are made to be in the 9 to 11 psi range.

I would think you don't want a set up that needs to spool up to 3000 rpm before it begins to build boost, if your are oly goig to rev it to 4000.

These truck engines are in the 3.7 to 4.1 displacement range making 130 to 150 HP. and though they are 4 cylinders they probably fit your needs better.

If you are going to go that way might you want to look at something like throttle body FI from something like a GMC V6.

I never even thought about the RPMs these flatheads run when I said the other stuff (I'm burned out from too much studying for midterms). I know for a fact that those small car turbos don't like to pull boost under 3000-3500 RPM, my friends turbo eclipse will pull VERY hard over 3500, but my 318 Dakota will get it every time up to 35 MPH! Diesel engines like to run in low rpm ranges, I agree that a small diesel turbo would probably fit your need better.

[mach0415]

What carburetor do you plan to use with your turbo?

Well, I have not done my research, but I have seen a 1 bbl carb on a turbocharged Ford 250 OHV inline 6 in a "forced through" design. I have a pretty sweet Stromberg BXVD-3 I may try.

[mach0415]

My 3.0 Mercedes Turbo Diesel spools at 1800 RPM. There may be more exhaust force driving the exhaust wheel, though, due to higher compression numbers. BUT with almost a half liter more of displacement, it may be in the range, so to speak, for exhaust pressure and volume. Perhaps a turbo from a diesel is in order. I will have to do more research, either way. Shaving the head some will be helpful, as well.

[Plymouthy Adams]

not sure of diesel but for the gas fired engine..you want to keep combustion at 8.0 or lower..

[Don Coatney]

Well, I have not done my research, but I have seen a 1 bbl carb on a turbocharged Ford 250 OHV inline 6 in a "forced through" design. I have a pretty sweet Stromberg BXVD-3 I may try.

What ever Carburetor you use it must be "tight" as in no passages open to the atmosphere unless it is fully "boxed".

[mach0415]

not sure of diesel but for the gas fired engine..you want to keep combustion at 8.0 or lower..

Yes, thats correct. Gasoline has a very low flash point, compared to light fuel oils, such as diesel. Diesels run 350-400psi, just to crack fuel molecules to combust. Gasoline simply will not explode at higher compression ratings. Most NA diesel engines are 23:1. TD engines run less, due to charging the intake air through a turbo. Our 6.5-7:1 flatties are perfect for small turbos, but the diesel vs gas debacle, in terms of exhaust turbine wheel speeds, will be determined by exhaust pressure and volume.

[mach0415]

What ever Carburetor you use it must be "tight" as in no passages open to the atmosphere unless it is fully "boxed".

You are absolutely correct. I could avoid this if I go with a "pull through" design

[Rusty O'Toole]

Have you considered fuel injection? It gets over a lot of problems associated with carbs/superchargers and not difficult or expensive these days. Look up Megasquirt home made EFI $140 for the kit last time I looked.

A flathead should go well with a turbo because they tend to pull strong at low to mid RPMs but run out of breath at higher speeds. So the turbo is ideal to make up the deficiency. And, they naturally have low compression.

Exhaust valve and seat cooling is a concern. Wonder if water injection would bring down the exhaust temp without killing boost?

I would be looking at turbos of similar HP not displacement, or a diesel model as being closer to the flathead power characteristics.