240_to_miata

iTrader: (2)

I actually MIGHT be having issues with mine. I am randomly only reaching my wastegate pressure here and there. Might be a boost leak or something, but I plan on checking my MBC too.

Other than that the NXS has been great so far.

curly

iTrader: (25)

Yeah you can't escape the sexual references. You could try messing with your t, I just gave up and paid $12 for a eBay ball and spring version. Which is linked in te thread I linked on page one of this thread.

Pen2_the_penguin

iTrader: (4)

Its the reason why I replaced the crappy t with a normal t and added a check valve.

flounder

Could I just remove the guts from the tee and use a check valve? I know it's retarded when they are so cheap anyway but at least I won't have to wait a week to get a new one.

Pen2_the_penguin

iTrader: (4)

yups. I did that actually before... until I lost it after tearing into my engine bay.

flounder

Ok, I went ahead and ran my vac/boost line off the tb intake pipe after the ic.

Initial impression- didn't do a damn thing to the boost creep/taper off issue, but did seem to smooth out my drivability mid throttle, on/off boost.

I think the real problem lies within the ball/spring tee like curly and pen mentioned. As you can see in the log, I surge to about 11psi and taper off to about 8psi within a sec or two. This is with one click on the controller.

I am going to try cutting the spring in half and see if that helps any. If not this thing is going in the garbage. I will update later tonight.

BTW, 11psi feels damn good! I added some fuel and pulled a degree of timing and I managed to see 12.0 afr@ at 85% dc with greentops and no knock during the 11psi surge.

flounder

Woah, cutting the spring in half made all the difference! Now with 5 clicks out on the controller it hits 10 psi and stays there. It may drop off a half lb after 6k but i'm just fine with that for now. My car is a beast! lol

I didn't do another log yet but I may go out again once the laptop charges up some.

I did notice there is a bit more lag then there used to be, not sure if its due to the distance away from the WGA or just due to the fact that i'm still rocking the stock muffler? I'll be ordering a nice free flowing one now that this issue is solved.

Happy and addicted to boost once again! Thanks curly and pen!

Pen2_the_penguin

iTrader: (4)

Glad it worked out... those Ts are evil man... evil...

curly

iTrader: (25)

In general those types of MBC have a slightly more delayed boost response. Either because of the long source line to the cabin or because of the bleeder valve design. Remember no air is lost in the standard ball and spring design.

Good job though, sounds like yours is working even better than mine.

flounder

I didn't even route it inside the cabin, it's sitting next to the turbo. (see pic) The hose from the tb piping to the T is probably 4 ft?

flounder

Well, I finally got around to buying a true ball and spring mbc. Picked up the nxs one off ebay.

I still have a slight issue with spiking but it definitely spools up quicker and hits harder that the other one.

The instructions that came with it recommended that for the least spiking, run it directly between the turbo and the wg. I was tapping into the tb inlet pipe previously and once I switched it back, it did cure a lot of the spiking.

I like it! Though it was harder to adjust than the other one. Very touchy, 1/4 turn is like 1-2 psi!

Techsalvager

I'm using the MBC that op has just fine, riding at near 180kpa from one click from 150kpa at closed.

flounder

Yeah the click style one took me from wga setting of 7psi to 10 psi with 5 clicks.

This one has no fancy clicker, just a jam nut and a bolt to adjust boost. Does feel like less delay than the bleed type.