Fitted intercool, oil & ps cooler & twin dump valves

Just finished fitting my new intercooler with 50mm tial blow off valves, my power steering cooler and my 30 row oil cooler. I must say i am quite happy- I wanted the B/v's just visible through the front bar side vents and they sit quite nicely and are just visible. I'm not 100% happy with where I have the oil cooler located- its sitting a bit high but I figure as I dont do any track work, and its a 30 row of which the bottom 10 rows are low enough to be getting direct air flow from the front 'mouth' of the bumper but behind th IC it will be ok...

You can see the BV's in this pic and the oil cooler poking up in the centre behind the intercooler:

Power steering cooler sitting behind the drivers side I/C piping

BV just visible below and behind the indicator

not very good lighting but you can just make out the BV's poking up inside the side vents

Looks a tidy job cant understand why you went with 2 BOVs with the power you are running, Your oil cooler is in the same place as mine its where greddy install them so should be fine bud.

Heres a pic of mine did pretty much the same thing:)

Excuse the power steering cooler its not fitted in place in that pic

You can just make out the BOV in this shot

Dibbs - OMG! I would be a very happy man to wake up to that every morn

Both great looking cars.

jIHWAAN, don't see many modded VVT-i's around these parts.

How are you managing to run Blow Off Valves on your car?

I assume you have an aftermarket ECU.

Have you changed from the factory 'Air flow metering Units' to 'Mass Air Flow Sensor'?

Certainly interested to know how you have achieved this.

hmmm... now here I didnt think it would pose a problem... but from what I know it should be fine- I havent actually had the car running with them yet but when I bought the car it had a HKS ssqv BV on it. From my undertanding even though it has AFMU and not MAF it doesnt matter- the throttle is closed at this stage so the air flow being registered passing the AFMU doent matter- it may dump fuel into the cylinders (which on my nissan motors setup like this causes a very nice flame out the exhaust) but other than that it doesn make any difference does it? someone weigh in on this please...

as for Dibbs asking "cant understand why you went with 2 BOVs with the power you are running" - I dont plan on staying at this power forever and am merely doing all these things first before I go single - or maybe some of the JDM hybrids speed for sale sell... either way I just think it looks better with two and it sounds better also if they are running different spring rates as one opens then the other opens.. I guess it really comes own to its just the way I wanted it- also so you can see them through the vents I think it looks better with two...

**EDIT DIbbs your car is sex.... damn... my dream supra... aerotop - manual - single and blue (I love rsp & I think that looks hot in that colour blue) !!!

Do you still have the stock air conn radiator installed?

Do you still have the stock air conn radiator installed?

Yep.

Why's that?

The way that I thought it worked was that a Mass Air Flow Metering unit will register an amount of air entering the system, and have that information stored.

What normally happens is when the throttle is closed on this set up, the air is by passed through a re-circulation valve and when the throttle is reopened the air gets feed into the system ECU knows it coming so appiles the correct amount of fuel and timing advance/ retard automatically.

I believe that if the system loses this air it will still be expecting it, what this will result in I am not sure, may just be an overfueling situation like you mention in your reply.

Definately interested in finding out how it goes, as the sound of a blow off valve is what owning a a turbo is all about (a little bonus isn't it).

Plus at higher boost levels the turbos should spool more freely with an atmospheric type valve, and prevent stall which is damaging to turbos over time.

If anyone can shed some more light on this.........

Yep.

Why's that?

I am about to start rebuilding my front end..... previously my Oil Cooler Rad was in front of the Passenger side wheel...... just curious how you managed to fit the Rad, Air Con Rad, Intercooler & Oil Cooler all in.......

What made you put it there rather than in front of the Passenger side wheel arch...... (not a critism!, If I am rebuilding I am genuinlly interested on the "best" place to put things)

Cheers

Rob

There is ample room for the oil cooler between the intercooler and the air con rad.- I put it there because it is a 30 row cooler there is no way it would fit in the passenger side in front of the wheel and it was very simple to fab a flat plate aluminium bar bracket to mount it there.. it couldnt go on the drivers side because that is where my P/S cooler is - plus it wouldn't fit there either and with it located where it is now I can have my remote oil filter mounted in front of the passenger wheel.

Pudsey- as for the AFMU with BV it doesn't cause a problem on any other car i have done this on (all nissans tbh- but still 3 litre straight six motors very similiar to the 2jz in basic princiapals) and I dont see how, other than overfuelling, it will cause any problem..

You can see in these pics the room still left between the oil cooler and intercooler. I mounted the oil cooler hard up against the air con condensor (radiator) because I used special foam strips about 1.5cm thick and as long as the cooler is wide on the top and bottom on the oil cooler- this way its in there very secure and won't wear against anything.

Hopefully it should be okay then judging by your past experience, certainly be great to hear your feedback once you have it up and running.

I dont think I will have any trouble as the BV that was fitted when I got the car was an atmo venting hks one about 5 inches before the T/B and it was fine with that (just sounded silly the whistling sound it made)

because I used special foam strips about 1.5cm thick and as long as the cooler is wide on the top and bottom on the oil cooler

Cheers for the information, where do I get said "special" strips?

Thanks

Rob

I dont think I will have any trouble as the BV that was fitted when I got the car was an atmo venting hks one about 5 inches before the T/B and it was fine with that (just sounded silly the whistling sound it made)

That's definately good information as I thought you couldn't do it.

Rather than replace my original when its needed with a factory one then, I may consider a uprated one.

Great stuff

Best of luck with the rest of your work buddy.

Cheers for the information, where do I get said "special" strips?

 

Thanks

 

Rob

-I got them from a local rubber and foam shop- I guess they are not really 'special' - I should have said "adhesive backed high density foam that can handle heat" but it was a bit to much to type. Any sort of high quality foam strips or even possible rubber pads on all four corners- just to stop the two coolers from coming into contact and wearing a hole in either one / each other.

That's definately good information as I thought you couldn't do it.

 

Rather than replace my original when its needed with a factory one then, I may consider a uprated one.

 

Great stuff

 

Best of luck with the rest of your work buddy.

I actually have to disconnect the factory one again myself as i had hooked it back up after buying the car as I hated the sound of the HKS BV..

Ill give some more feedback when I get this going but I am 99.98% sure it will be fine (not least of because the car had the hks one on before and the fact I have done and know many people who are running atmo BV's)

The way that I thought it worked was that a Mass Air Flow Metering unit will register an amount of air entering the system, and have that information stored.

 

What normally happens is when the throttle is closed on this set up, the air is by passed through a re-circulation valve and when the throttle is reopened the air gets feed into the system ECU knows it coming so appiles the correct amount of fuel and timing advance/ retard automatically.

 

I believe that if the system loses this air it will still be expecting it, what this will result in I am not sure, may just be an overfueling situation like you mention in your reply.

 

Definately interested in finding out how it goes, as the sound of a blow off valve is what owning a a turbo is all about (a little bonus isn't it).

 

Plus at higher boost levels the turbos should spool more freely with an atmospheric type valve, and prevent stall which is damaging to turbos over time.

 

If anyone can shed some more light on this.........

Your right Pudsey- she overfuels a little- but it doesnt affect anything...

just in case anyone stumbles on this thread with two BOV's hooked up on my VVTI Jspec it pop's n farts every now and then(overfuels nd backfires a little) but otherwise runs fine, dump valves sound so nice- not over the top or anything at all.. and with both hooked up you can distinctly hear one open then the next on certain throttle changes- sounds like a two stage BOV type things ... hardto describe- pssshhhhhSCHWOOOSHH kinda lol

The following is my experiences with a Skyline R33 GTR I had many years ago, the same will apply to a MKIV though, air flow metering wise, with vent to atmo BOV's. I never run any form of BOV on a turbo engine these days, and nor do any proper turbo race engines I know of. Originally a BOV was used just to reduce the noise of a turbo on a road car when the throttle is suddenly lifted. I can find no logged evidence wahsover that a BOV reduces lag, nor extends turbo life, and Turbo Dynamics and Turbo Technics agree, as do AER, IES and EDL.

The following is based on my Skyline experience, with air usage

measured by air flow meters before the turbos. It is not applicable to

cars that soley use a MAP sensor and throttle angle for air measurement .

To recap I put in a bigger intercooler and the standard Skyline duct

that runs across the lower front of the car taking dumped air from the

2 blow off valves to the intake between the air flow meters and the

twin turbo inlets was masking air exiting the lower 4 rows of the new

IC.

Having spent a good deal of money on this item it pained me to see some

of effectively blanked off. So I decided to blank the inlet off

altogether where the cross pipe entered the turbo inlet ducting, remove

the cross pipe and vent to atmosphere. The dump valves were being held

open at idle by the idle vacuum level, so after ages of pondering i

made a set up of solenoids to control when vacuum was applied to the

dump valves. This set up worked perfectly. *HOWEVER* a much more

serious problem occurred, which any similarly inducted turbo car will

potentially suffer if the boost air is dumped to atmosphere rather than

as standard into the air intakes after the AFM (s). On the overrun,

after a period of boost running, the standard set up will recirculate

the excess boost back into the turbos, through the IC, and back through

the dump valves to the turbo inlet again until the turbos inertia has

slowed them to the point of little or no boost. The AFM's do not see

any more air entering the engine, as it is being recirculated.

However, when we dump to atmosphere, that air is lost from the system

and the turbos draw in fresh air via the AFM (s). This causes the

engine to go mad rich, as the throttles are closed and no fuel is

really needed. Hence the black smoke seen on the overrun after my mods.

Worse still was a noticeable but very short period of detonation when

coming hard back on the throttle. This puzzled me totally, then it

dawned. As the fuel system started working normally again the Lambda

sensor "caught up" with what was happening, saw a very overly rich

mixture, and shut down the injector pulse width, creating a very lean

mixture, causing a brief, but very dangerous period of detonation!

I spent the afternoon and evening making new bracketry for the IC, new

hoses and adaptors and shifting the IC forward that critical 40 mm or

so, enabling me to fit the original moulded duct from the BOV's behind

the IC without blocking it. Quite a lot of work and fabrication...

However, the mod I was planning could well have caused damage, and is

certainly something to be very aware of if one has a similar AFM pre

turbo set up changed to dump boost to atmosphere. The type of BOV

matters not, it's the fact that the air no longer re circulates but is

lost from the system, confusing the AFM (s) into thinking the engine is

wanting more air/fuel mixture. An oscilloscope on the O2 sensors

confirmed what was happening. We live and learn, often the hard way,

but in this case not as hard a lesson as it might have been. I hope

this helps, I searched the web long and hard for references to BOV

problems, and failed to find any details of why dumping to atmosphere on

none MAP sensor systems, that aren't mapped for this, is potentially

dangerous.

I can now finally make some proper seals to make sure all air entering

the radiator ducting passes through the IC, something HKS totally fail

to address, at the moment most air will go around rather than through

the IC core.

I read that before Chris, and I've got a question about it - why was your Skyline running in closed loop during high boost and gearchange operations...?

Closing the throttle and overfuelling is a given in an MAF car as you rightly say, the already measured air never reaches the cylinders - so black smoke, and potential stall at low revs. But you're out of closed loop at this point due to a rapid change in throttle position - and even more so when you nail the throttle open again after shifting gear. So why would the O2 sensor output of "omgrich" have any bearing on the fuelling situation?

-Ian

Dunno Ian, but that's what it did, I am no mapper and sure as hell I am no electronics wizard. I fussed and fretted over it until realising that BOV's were unnecessary anyway, which has saved me a lot faff latterly.