Vacuum Pipes

[JoeT]

Hi guys,

Quick question, should the vacuum pipes on the B16 A engine be connected? Since I got mine back from Watsons rally they've never been connected, I'm thinking this may have something to do with the 147Bhp at the flywheel...

Your thoughts would be great please!

[JoeT]

There seem to be a couple just above the air filter, also I have just noticed that someone had cut and blanked the fuel pressure regulator vacuum pipe, the only place it's been however is track n road, maybe they did it....

[duck]

JoeT which B16 engine do you have ? the early ones have 150BHP

[JoeT]

According to Geoff at Watsons (and what I paid for) it's the 160Bhp engine, it does look a bit old though so it wouldn't surprise me... :oops:

[duck]

JoeT - what number is stamped on the engine block ? might be able to figure out what BHP is should have by the number.

[fbm-spec]

I believe the vac pipe should be connected to the fuel pressure regulator on the fuel rail for the following reasons :

Fuel injection times are normally based on a constant differential pressure across the injectors . I.e the rail pressure has a fixed positive pressure in relation to the manifold pressure. It is true that the ecu map could be ' fudged' to allow for this but can cause problems at lower end of the power range. e.g. it may not be possible to control idle mixture effectivly when running rail pressure referenced to atmospheric instead of manifold pressure.
I did ask a few vtec owners at the last meet about this very subject. Some had them in place others didn't.

[JoeT]

There seem to be a couple just above the air filter, also I have just noticed that someone had cut and blanked the fuel pressure regulator vacuum pipe, the only place it's been however is track n road, maybe they did it....

The one above is left.

The fuel pressure regulator one:- I have a pipe but it is blocked in the middle by a plastic 'ball'. I did ask Steve and Geoff about this and they said something about DTA not requiring it (but honda ecu does), hence why it is blocked off. Cant remember the reason.

Yes DarrenW I think your right, I just phoned steve and he basically said the same thing, but the vacuum pipe above the air filter apparently shouldn't be open, and should be blocked off, so I'm popping back to track 'n' road tomorrow evening at about 4pm, so if anybody's about in the area pop on down!

[nominous]

On a Honda, the one for the FPR connects to a solenoid wth switches it based on commands from the ECU between atmospheric and intake manifold pressures.
Check the back of your intake manifold for a small vac pipe barb, and check its blocked!

[JoeT]

JoeT - what number is stamped on the engine block ? might be able to figure out what BHP is should have by the number.

Hi duck,

The plate on the engine itself says 'B16 A2'

Which i am pretty sure is the 160Bhp one.

It's just 13hp under, but only 110Bhp atw

Whereas most of you guys are getting 140 odd at the wheels and 160Bhp at the flywheel, so that's another 30 odd brake I'm losing out on somewhere! :evil:

[duck]

Yes the B16A2 is 160BHP.

Don't forget that different rolling roads get different results.

[Mark D]

the 2 vacuum pipes on mine arnt blanked off and ive got 174 at the flywheel, the first place id start to look is the mapping

mark d

[JoeT]

Yeah I've spent a total of around 6 hours on the rollers at Track 'n' road to produce the 147 Bhp (I will be trying it on the rollers at my work soon too), the difference was phenomenal! I'm not unhappy with the performance at all, it's just good to know that I'm getting the full potential, and after all, it's how the hp is being used I guess...
I think it's gonna need a blower in a year or so anyway ( :) ) so I'll be happy till then!