NB2 intercooler routing suggestions (paging 18psi)
 

Hey All,

I've looked at many a intercooler photo, and it seems that routing on the 2001+ with A/C and P/S is the hardest. People seem to like 18psi's handy work, but those photos have since expired.

The intercooler I got has 2.25 inlets (despite advertising as 2.5). Is there any downside to changing diameters multiple times? The turbo outlet is 2.25, and some people go with 2 inch on the hot side, then the TB is 2.5. What if I put 2.25 as far as I could go on the hot side and then reduced to 2 inch if the fit is too tight before bumping up to 2.25 before the intercooler, then starting with 2.5 at the TB and reducing to 2.25 where I need to for fitment? Or just make my life easier with a 2 inch kit and the appropriate reducers?

You shouldn't have any trouble doing 2.25" all the way on an NB2. Use the holes behind the headlights.

Narrower plumbing definitely makes routing easier.

What you want to avoid is downsizing in the chain from the turbine outlet to the TB, that'll throttle your airflow.

ie. If your turbine outlet is 2.25" and your intercooler barbs are 2.25", keep the hotside plumbing 2.25". For the coldside use 2.25" and a hose reducer elbow from your TB to the 2.25" coldside plumbing.

I fit 2.5 behind the headlight, just needed a tiny bit of massaging.

2.25 all the way on both sides is totally fine, no need to make steps or change diameter several times

Could you repost your routing photos? The left headlight has a hole that could just be enlarged, and I'm guessing you put a hole in the other side in the same place?

Yeah, when I'm home.
nope, the cold side is "traditional" routing. I saw no reason to hack a hole when it's so easy to route as is.

I just enlarged the dr side hole and mimicked MSM routing with larger piping

https://www.miataturbo.net/attachmen...ine=1449169629

https://www.miataturbo.net/attachmen...ine=1449169741

https://www.miataturbo.net/attachmen...ine=1449169741

https://www.miataturbo.net/attachmen...-hotside_1.jpg

https://www.miataturbo.net/attachmen...ine=1449169923

https://www.miataturbo.net/attachmen...ine=1449169923

https://www.miataturbo.net/attachmen...uild-holes.jpg

Thanks! I've got the same tires, and had the same wear on the front :)

18psi - is "traditional" routing on the cold side straight down from the TB, under the sway bar, and a 180 around the rad? Or something else?

You don't have to do a 180 around the rad. I just did a 90 coupler to a 45* pipe, and it drops it right under the TB.

Would I do either routing again? I don't know. Hot side makes more sense than cold side. Both may require a custom wastegate actuator bracket. I bought one online that did the job in the end. This one:
Garrett Actuator Wastegate Bracket Fits All GT25R GT28R GT30R GT35R GT40R GTX T3 | eBay


https://www.miataturbo.net/attachmen...ine=1449170324

Bumping an oldddd thread!

To anyone that fit 2.5 inch piping behind the headlights, how much material did you have to take out of the hole? Did you just whack it a few times? Grind some ish off with a dremel or was it more involved?

Thanks!

You can cut it. I didn't. I made small relief cuts and pounded it out to form a lip in the same general shape as oem but larger. I believe the oem hole fits 2" or whatever the MSM piping is. So enlarging it for 2.5 is only .25 more on each side

It wasn't a big deal. Dremel plus split rubber hose to act as an edge guard.

I will be selling the pipes pictured above in a month or two (BOV included). Not sure I want to ship. I could be persuaded I guess.

Pretty sure I ran 2" on the hot side and only required minimal trimming.

Ah gotcha. I guess I can give it a go! I can measure out and draw the slightly bigger shape and nick it till it fits.

Thanks. It would be nice to press the easy button, but I already have piping and I am going to be a dead man if this car isn't running well before that 1-2 month period.

I'm shooting for 2.5" with 2" as a backup if it just doesn't work for whatever reason.

https://cimg4.ibsrv.net/gimg/www.mia...ef6f46b686.jpg
You can sneak in two 2.5" pipes if you're careful.

Just grease liberally and take your time with it.

I really like that picture above. ideal intake and fmic routing.
if I got another miata that I din't care about keeping reversible (because I wasn't about to hack up my mint low mile MSM), I'd do exactly that.