Converted to a blow through VAM setup today!

Brantley · Mar 21, 2004

Today I converted to a blow through VAM setup! I had been thinking about doing this for a few months, but never gave it any serious thought. A week or so ago there was a long thread about it on TuboFord. After reading that thread, I decided I had to give it a try. The hardest part was getting the mandrel bent pipe angles cut correctly so that everything would line up. There's not much room between the IC outlet and the TB. It took a while to get the VAM tuned right. I tried many different tension settings on the VAM door spring. In the end, I tightened the spring by about 1/3rd of the wheel's diameter, and so far with 17psi of boost, the A/F ratio seems to be pretty good. It's a little rich at idle, but nothing that I can't live with. Moving the VAM close to the TB made a huge difference. Engine cranks faster, idles better, much more responsive at any given point on the powerband or load, no more bucking when slowly getting out of boost, and the turbo sounds cooler. It feels like a different car! 17psi with the blow through setup feels stronger than 17psi with the stock draw through setup. I wish I had done this months ago. I should be able to get 19 or maybe 20psi out of it before I have to start tuning the VAM spring tension and fuel pressure again. I might just have to deal with an overly-rich idle in order to get enough fuel at WOT, but I'm not sure yet. That is a small problem compared to the issues that the blow through VAM setup solved.

So far I only have about 150 miles on it, pretty much all of it highway. However, at this point, the results are very good! The difference is amazing. Hopefully over the next 2 or 3 weeks I'll get a feel for how it's going to work for me in the long term... but based on what I've read on TurboFord, I should be good to go since my A/F ratio is about where it needs to be.

Summit is going to love me for doing this conversion.. I now need so many more t-bolt clamps, it's not even funny.

latroca1 · Mar 21, 2004

Was wondering what the blue and red canister is with the plumbing to the iac location??

Bearded Forever · Mar 22, 2004

Is the bov hooked up before the throttle plate?

Brantley · Mar 22, 2004

latroca1 - that is the Bailey blow off valve

Cro - no.. The vacuum port on the IAB blockoff plate is using the side that goes behind the throttle blade. I haven't used the IAB in months, so I decided it was time to get rid of it. I also wanted to make the vac line shorter to the BOV, so I thought I'd give it a try. So far, it seems to work fine and is more responsive that my old (longer) vac line.

140cilx · Mar 22, 2004

Will pick your brain next autox we hit.

latroca1 · Mar 22, 2004

Don't mean to sound stupid but what exactly does the bov do?
Does that let back pressure out for the turbo??

Brantley · Mar 23, 2004

140 - I'll try to get up with you soon so we can plan the next autox we're going to go to. Time is starting to run out.. I graduate in May and then will be hitting the road again, so I don't have too much longer. I need to check the CRSCCA schedule and see what's coming up that I can make. I can't wait to go racing again, now that I am finally spooling up quicker and my rear control arms are tight!

latroca1 said:
Don't mean to sound stupid but what exactly does the bov do?
Does that let back pressure out for the turbo??

The BOV lets out pressure in the intercooler and pipes when you let off or close the throttle. This keeps the "wave" of air that bouces off the throttle body blade from slamming back into the compressor wheel of the turbo. This makes the turbo last longer, and allows it to spool up much faster after shifting gears.

Xanax · Mar 23, 2004

Brantley said:
Today I converted to a blow through VAM setup! I had been thinking about doing this for a few months, but never gave it any serious thought. A week or so ago there was a long thread about it on TuboFord. After reading that thread, I decided I had to give it a try. The hardest part was getting the mandrel bent pipe angles cut correctly so that everything would line up. There's not much room between the IC outlet and the TB. It took a while to get the VAM tuned right. I tried many different tension settings on the VAM door spring. In the end, I tightened the spring by about 1/3rd of the wheel's diameter, and so far with 17psi of boost, the A/F ratio seems to be pretty good. It's a little rich at idle, but nothing that I can't live with. Moving the VAM close to the TB made a huge difference. Engine cranks faster, idles better, much more responsive at any given point on the powerband or load, no more bucking when slowly getting out of boost, and the turbo sounds cooler. It feels like a different car! 17psi with the blow through setup feels stronger than 17psi with the stock draw through setup. I wish I had done this months ago. I should be able to get 19 or maybe 20psi out of it before I have to start tuning the VAM spring tension and fuel pressure again. I might just have to deal with an overly-rich idle in order to get enough fuel at WOT, but I'm not sure yet. That is a small problem compared to the issues that the blow through VAM setup solved.

So far I only have about 150 miles on it, pretty much all of it highway. However, at this point, the results are very good! The difference is amazing. Hopefully over the next 2 or 3 weeks I'll get a feel for how it's going to work for me in the long term... but based on what I've read on TurboFord, I should be good to go since my A/F ratio is about where it needs to be.

Summit is going to love me for doing this conversion.. I now need so many more t-bolt clamps, it's not even funny.

Ouch it looks like someone
will be under the hood and Summit will be getting some business.

Pro-Hawk · Mar 23, 2004

Brantley said:
The BOV lets out pressure in the intercooler and pipes when you let off or close the throttle. This keeps the "wave" of air that bouces off the throttle body blade from slamming back into the compressor wheel of the turbo. This makes the turbo last longer, and allows it to spool up much faster after shifting gears.

Ok now for another newb question

On that BOV it looks like you just mount it and run a vaccum tube to the TB is this right are is there something I can't see? I got a stock set up but was thinking of using one of these BOV to improve spool up time.

Thanks

140cilx · Mar 23, 2004

Pro-Hawk, you are correct. Any vacuum source after the TB, whether it be the vacuum tree or intake, so that when the TB is closed it is opened by the vacuum created. The Bailey is actually a 2 piston set up, boost pushes on one piston, and when vacuum opens the 2nd piston, the pressurized air escapes. It's one of the best for our cars because we'll have no "leaks" like single piston types use when we are just cruising or not boosting.

It will really help out your svo when you are acclerating hard and running through the gears. Instantaneous boost after shifting.

Brantley · Mar 23, 2004

Yesterday and today I have had problems keeping the hoses connected to the TB side of the VAM.. Worm clamps just simply aren't strong enough to sufficiently clamp 3" radiator hose. I just ordered some t-bolt clamps from Napa, so hopefully tomorrow I'll be back up to some nice high boost. I am pretty certain now after driving it a bit more that there is more power at a given boost level over the stock VAM setup. Too much fun

EDIT: I have also noticed that the blow through VAM has completely solved my backfiring problems when letting off the gas. Makes lots of sense - before there was too much "lag" in the system from when the air was metered to when it actually went through the TB. Also, it definately spools up faster.. very noticeable from a rolling start.

On a side note, this past Friday was a historic day for my Mustang. It passed NC inspection! I have owned/driven the car 2 years with no inspection sticker! Got pulled once a year ago, but the trooper let me go and said to get it fixed.. lol It's so nice to drive by a cop and not have to be paranoid.

Xanax · Mar 24, 2004

Crovax said:
Is the bov hooked up before the throttle plate?

NO

Pro-Hawk · Mar 24, 2004

Brantley said:
EDIT: I have also noticed that the blow through VAM has completely solved my backfiring problems when letting off the gas. Makes lots of sense - before there was too much "lag" in the system from when the air was metered to when it actually went through the TB. Also, it definately spools up faster.. very noticeable from a rolling start.

At what RPMs was you doing when you let off the gas and the car back fired?

***The reason I ask is the system is set up to cut the fuel off when the gas is let up off of at higher than 1800~RPMs. If lets say your doing 2k rpms and let off the gas pedal and it back fires there is something up. The car is getting fuel when it shouldn't, probly a leaking injector or FPR. That is how it was explained to me anyways ***

Pro-Hawk · Mar 24, 2004

140cilx said:
Pro-Hawk, you are correct. Any vacuum source after the TB, whether it be the vacuum tree or intake, so that when the TB is closed it is opened by the vacuum created. The Bailey

Dang and here I was thinking it was going to be a hard deal to add on ) Thanks

Do you got a part number or is that the only model they make ?

Brantley · Mar 28, 2004

Pro-Hawk said:
At what RPMs was you doing when you let off the gas and the car back fired?

***The reason I ask is the system is set up to cut the fuel off when the gas is let up off of at higher than 1800~RPMs. If lets say your doing 2k rpms and let off the gas pedal and it back fires there is something up. The car is getting fuel when it shouldn't, probly a leaking injector or FPR. That is how it was explained to me anyways ***

Sorry, I meant to reply sooner, but forgot. I've been pretty busy in the last couple days. It would backfire at just about any RPM or vacuum/boost level as long as I was at least 1/3rd into the throttle. Basically, if the injectors were putting out a modest amount or greater of fuel, it would backfire. But no more!

Yesterday I finally got the t-bolt clamps on there. Much better - pipes stay on now.

Lx89Stang05 · Mar 28, 2004

wheres your IAC???

Pro-Hawk · Mar 28, 2004

Whered you get that BOV and that Cam gear?

Brantley · Mar 28, 2004

The IAC is in the parts pile in the corner of the basement! On my engine, it caused more problems than it fixed, so I just tossed it. Things work better without it. When the engine is cold, it's a bit of a pain to keep it running when stopped, but after 1 minute or so, it will idle fine on its own.

The adjustable cam pulley is from Race Engineering. The BOV is from roadsterperformance.com, but they are no longer in business. If I had to do it again, I'd get a Forge BOV from Bob on TurboFord.org.

Pro-Hawk · Mar 29, 2004

Brantley said:
The adjustable cam pulley is from Race Engineering. The BOV is from roadsterperformance.com, but they are no longer in business. If I had to do it again, I'd get a Forge BOV from Bob on TurboFord.org.

Is that the same www.40bob.com ?

I'm not sue I could work that cam pully but it would sure look good on my car

Brantley · Mar 29, 2004

Pro-Hawk said:
Is that the same www.40bob.com ?

I'm not sue I could work that cam pully but it would sure look good on my car

Yes, that's Bob (40bob) who sells the Forge valves.

The cam pulley is very easy to adjust. I'm sure you could figure it out. Once you see it in person, it's very obvious how it works.

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