3B turbo Q's

[Otterav]

Hey,
I am in the process of collecting the final bits and chunks for my FJ-BJ mutation. I am gonna install a 3B from a 24V BJ-42, I am toying with the idea of turboing the beast. My question is I plan on using a BT manifold P/N #17141-58011. I have not sourced the manifold yet, but does anyone know the mounting stud spacing? Also what turbo would be the optimal choice, ie no adapters, straight bolt on, best A/R, ect.
Whew
eric

 

[cruiser_guy]

You want an intake A/R of about 0.42 and an exhaust A/R of about 0.48.

 

[cody c]

a flipped stock manifold and lebaron turbo or d50 turbo out of a mitsubishi would be the simplest if thats what you are asking. merkur turbos work too but require a little more fabrication. unless you want to get a 13bt manifold $500 and custom adapter plate and go the way wayne or brownbear went. More expensive but probally better overall.

Cheapest and best arent usually the same thing.

the search function is helpful as well.

 

[brownbear]

Hey,
I am in the process of collecting the final bits and chunks for my FJ-BJ mutation. I am gonna install a 3B from a 24V BJ-42, I am toying with the idea of turboing the beast. My question is I plan on using a BT manifold P/N #17141-58011. I have not sourced the manifold yet, but does anyone know the mounting stud spacing? Also what turbo would be the optimal choice, ie no adapters, straight bolt on, best A/R, ect.
Whew
eric

No adapters is a CT-26 toyota turbo. Turbonetics makes a small housing just about in the size you want. Its a ct-26 type flange that mates to the 13b-t manifold.

 

[UpsideDown]

You want an intake A/R of about 0.42 and an exhaust A/R of about 0.48.

These numbers are somwhat debateable. The size of the turbo itself matters, as do the A/R numbers.

The intake A/R is not so important as the exhaust A/R - over some discussions, locally, a few of us feel that a small A/R won't give enough top end and we are looking for numbers like .63 at the exhaust side. It would be a good idea to look at a compressor map for whatever turbo you choose and see if you can punch in some numbers regarding your engine's expected operating range and see how it fits the map.

The advantage of a small A/R is that the turbo will spool up quickly, but you may limit flow at the top end (or over-rev the turbo).

The bigger A/R will spool up more slowly, but give better boost at the top end.

 

[cruiser_guy]

The intake A/R is not so important as the exhaust A/R - over some discussions, locally, a few of us feel that a small A/R won't give enough top end and we are looking for numbers like .63 at the exhaust side.

An exhaust A/R of 0.63 puts you into the range of a Supra turbo which is often thought of as being too large.

It really depends on the speed at which you normally operate your engine. I like to keep mine in the low to mid 2000's with only rare forays into the upper end of the range (pulling steep hills for instance). If you regularly are in the upper end of the rpm range then the larger A/R will likely work better since it will have a lower back pressure but a later spool up (needs more rpm to get the same boost).