From a post elsewhere, I've seen either Robert or Scott recommend a 3.25"-3.5" inlet as the flow rate on the Red and black can get high enough that 3" will cause some measureable losses.

The 80mm compressor inlet is also 3.25”, if you are on a Red or Black, might as well not choke it down in size.

 

Any pre turbo restriction means increased head that the turbine has to overcome which in turn means a limit of both efficiency and max output. Free flow is the best way to go.

 

note to self, 4" intake and speed density

 

make another note to not bump old threads

 

A few questions:

(1) So where would one buy a 3.5" or 4" intake ?

(2) What would the expected benefits be on an HTA Green going from MAF to SD ?

(3) What does one do with the DV ? Does it just vent into the engine bay (vs. recirc.) ?

 

I've had a nice 4" dejon intake and 9" Amsoil filter sitting in my garage for the past year or so just waiting to go in. I knew it would be a chore of an install since I have the stock UICP, stock battery, huge Synapse DV and ACD (reservoir right by filter).

So, since I'm finally back on SD again, I decided to install it yesterday. Well, over 2 hours later, and I'm back to exactly where I began. Everything was so frickin tight and hard to get in there...I had everything connected and in.....about 95%. There was just no way in hell it was going to go 100% though. I was pretty bummed about it. I even scratched the beautiful intake pipe in a couple places as well as the filter.

Plain and simple, I either need a mini battery or battery relocation and a short route UICP to fit the monster intake, filter, and synapse in that area. I sort of had a feeling of that going in, but since I have been putting this off for about a year (I just hate working on my car anymore) I decided to get it done.

So, now, I have to do a battery relocation (I won't run a mini for various reasons I don't want to write a book about) and buy a short route IC. So, just another 'project' that has to wait for me again. I have to shop for all the proper parts (1/0 gauge wire, circuit brakers, distribution blocks, battery case/tie down, etc, etc, etc. Maybe in another year.

 

Westco Miata battery...
Much smaller, 25 pounds and a VERY good battery.

 

How big are the batteries on the US cars? The JDM ones are the same as a Nissan Micra, so we just pop down to the local car place and get one of those. Not anywhere near as small as the Odyssey race batteries, but still quite tidy.

 

+1