Crown Headers on 1UZFE

Forced Induction is the hottest trend in the Lexus-Toyota Community and 95% of Lexus-Toyota V8 owners want some type of forced induction like turbocharging, supercharging or even NOS.

However, those options are limited in the V8 world.

Why is it so hard to buy or to make a turbo kit for the Lexus-Toyota V8?  Well, its a lot work for one and secondly, not much room available for the turbo to seat.

Recently I got a set of Toyota Crown headers or exhaust manifolds from a local junk yard who imports Lexus parts from Japan.  For some unknown reasons, he imported few sets of Toyota Crown exhaust manifold.  I got a set for $80 with the intention of cutting the exhaust manifold apart and just make use of the flanges.

Since I have some time, I mock fit the headers before I cut it up.  Here are pictures of the Crown headers in a 1UZFE engine.  Remember, I swap the left header to the right and right to the left then turn both of them upside  down.

By swapping and turning upside down, the heads bolt patterns fit perfectly.  Its a isomer fit like left hand and right hand.  The reference below is based on left hand driver car like the US Spec. cars.

Here is a view of the front of the engine with two headers facing forward and down.	This is the driver side (DS) head with passenger side (PS) header.	Another view of the driver side with exhaust coming out at 90 degree angle.
The is the PS head with DS header turned upsidedown.	Another closer view of the PS head.	This is a view from the rear of the engine. You can see the two headers are facing away.
This is the front view looking down from the top.	Same as previous but now looking at two headers.	This is a top view looking at the headers.
The DS head and detail view of the header.	The exhaust pipes are 1.5″ and the collector pipe is 1.75″	A closer look at the flanges and exhaust oulet pipes entering to the collector pipe at 90 degrees.
More details of the header	Did some mock installation with AC compressor. The flange needs to be cut to clear the AC.

I told all those pictures before I cut up those headers for the flanges.  Actually those headers are very bad in design.  First of all, those exhaust outlet is entering the collector pipe (log style) at 90 degrees.  It not thermodynamically sound.

Secondly, the collector pipes are slightly too small.  If you really want to do a FI project, I don’t recommend these headers.  They are restrictive and unsound engineered.  However, these headers can be modify to make a twin turbo out of it.  Twin T3 would work very good in this stock oem design  On the other hand, this article will give you some ideas how you are going to make your own DIY Turbo Project.