Do the 1993 CTD's have the 18cm or 21cm turbo housings? I've searched but can't seem to find the answer.

 

89 - 91 1/2 used 18 the 91 1/2 - 93 used a 21 if im not mistaken,

 

So a 16cm housing on my '93 would be a huge improvement. Does the smaller housing improve or worsen EGT's while towing?

 

It should lower EGT's while towing. At least that is what happened for me and I haven't match ported it to the exhaust manifold yet.

 

89-91 -18cm 91.5-92 21cm 93 18cm. Not a big improvement or noticeable difference between 18 and 16cm housing.

 

The 93 uses an 18.5cm2

 

According to this page the 93 uses the 18.5 cm2. Only the 91-92.5 used the 21.

Edwin

 

true , sorry i forgot

 

So a 92 has a 21cm, if you go to a 16 will that be significantly better.
Is that similar to a 18cm to 12cm change? The math is close.

 

I went from the 18 to the 12WG with the WH1C. I haven't regretted it. Some report that the 12WG is restrictive in some cases but a mildly bombed pump shouldn't be an issue. I plan to do more work on my pump though so stay tuned.

I also drilled the center divider to allow better flow for the front three cylinders FWIW.

The 21 to 16 swap will be a great improvement especially when you turn up the fuel. A BHAF and a 4" exhaust will help also I'm sure.

Edwin

 

Yes, the improvement will be similar. Going from a 21 to a 12 is mind boggling, it's like a whole different truck.

 

Does anybody have a pic of the drilled divider? I need to take my 12cm2 back off and grind out the ports to match the gasket and drill the divider. It would be nice to know what it should look like. I'm still keeping my eyes out for a cheap 14cm2 housing but for now I like the 12 much better than the 18.5 I had before.

 

Why yes I do.

 

Cool! Thanks alot!