So I wanted to get some opinions on the map sensor adapters for aftermarket DV's and such.

I just installed the Turbosmart Kompact DV (yes the plumb back) on my car the other day. One thing I felt a little concern about is the Boost Tap adapter seems a bit ...shallow? Once you put the MAP sensor into it there's basically very little open space inside of it. If you look into the holes for the nipples all you basically see is the sides walls of the MAP sensor and maybe a mm gap where your vac/boost can get through.

Is this normal? I'm looking at a few other adapters and most of them appear to be taller to prevent the MAP sensor from taking up all of the space and blocking off your boost/vac source which is the whole point. I think the TS DV would operate a lot better if this gap was larger. I cant imagine the vacuum being strong enough to open this valve. Which could explain why it just flutters when purging low to mid boost....

thoughts?

 

N18 engine doesn’t create vacuum in the manifold, so.... not enough vacuum to open the valve could be the reason for the fluttering. I have the Forge valve, which tees off the vacuum pump, but still uses the ECU controls to decide when to open and close. I’ve been thinking about ditching it and going with the GFB DV+ set up.

I have the Torque Solutions boost tap feeding my boost gauge. Seemed to install fine, and my gauge reads with credibility.

 

It opens up fine when you get into high boost. what doesn't make sense to me is if there's no vacuum in the manifold then how is this valve even opening...??

 

No clue, but I’m sure it’s not as effective as it could be due to the limited vacuum source.

 

What does the N18 Forge Recirc kit use for a vacuum source then? I noticed the N18 kit doesn't have a MAP sensor adapter.

 

The Forge kit uses a tee connection at the vacuum pump, with an ECU controlled solenoid to open the valve the same manner as the factory diverter valve. The advantage of the Forge valve is the mechanical actuation.

 

I'm going to assume that since the Turbosmart doesn't have a Solenoid that t'ing into the same vacuum source probably isn't a good idea?

 

I have a BSH dual boost tap as a signal source for my vacuum/boost gage.

https://bshspeedshop.com/product/bsh...ual-boost-tap/

When I am coasting off the throttle I get 10 to 15" Hg of vacuum. I use the gage to keep the manifold pressure below zero and get 38 to 40 miles/gallon.

Bur then, sometimes I'll get the urge to be a boy racer and my mileage can drop to 25 MPG.

 

Won't be a good idea. Without the solenoid, the valve will always see vacuum, and always be open.

The BSH only works on the N14 engine, not the N18.

 

^ What he said. N18 Here

 

I have a N14 engine and the title of the thread is "Best Boost Tap?", not "best boost tap for an N18 engine".

 

I'm just basically trying to find a boost tap source on the N18 that has a stronger vacuum when off throttle. But with all the research I can assume it doesn't really exist.

 

the N18 has variable lift on the intake valves . When the engine is cold the ECU uses the throttle body and you'll see vacuum like the N14, then once it is warmed up a bit it switches to variable intake valve lift and opens the throttle body plate all the way and there's no vacuum from the intake manifold. I see that on my boost gauge in the winter.

The N18 uses the vacuum pump for the brake booster, etc., you would have to T into that like njaremka said.

 

But if the vacuum pump is always creating vacuum my BPV would be stuck open.

I went ahead and shortened the hose between the Turbosmart BPV and the boost tap. I also re routed the line so that the banjo nipple on the BPV faces straight back to the rear so there's as little travel distance as possible.

 

oh yeah forgot about that. Seems like the updated stock valve with a stiffer spring would handle increased boost and also have the fastest response since it is controlled by the ECU, which is going to be faster than waiting for vacuum to build enough activate the valve.

Or the GFB solution. I have been thinking about how to re-do the plumbing so it could fit on the N18.