I ran VTA for one day. My car was notably slower and did not like the rich swings in AFRs on shifts. I never stalled out and my idle was fine. I'll be running VTA again when I switch back to a standalone and can properly tune it.

 

Well what bov did you have?

 

Your not risking anything by VTA...

Your cars not gona blow up from rich for a milasecond. Its actuality cooling the pistons off with excess fuel. By the time your done with the shift your AFR's are already back to normal and stable.

Your not going to stall or have any other issues. 300 million people have VTA and no one has any complaints. It does NOT hurt performance... it does NOT hurt the motor... it has no adverse effects at all.

I can understand being scared of things you don't understand but i'm telling you from tons of experience.... your fine VTA.


Its not always about the "sound" but more about being the better choice. If you dont need to recirc then why go to the trouble to create more clutter, mess, and boost leaks. For the most part... the benefits of VTA out weight the short comings of recirc. < The honest truth!

 

Open mouth Insert foot! lol

 

im sorry but a valve WILL NOT CHANGE WHP. Its only job is to stay closed in boost and open when the TB closes. With a maf, all you need is a valve that is closed at idle. I prefer the forge004 but you can use the hks ssqv or greddy type s/rs and a handful others. If the valve isnt closed at idle, you will have issues at idle and can stall out between shifts.

 

What about the turbosmart BOV that can vent to air and recirculate at the same time?

 

^ Your talkin about a 50 / 50. Its just anouther nice option if you want the sound.


But I'm gona say the same thing as cincy... its a valve. You WILL NOT gain any HP from it.


And not only that but when you put a car on the dyno the BOV does NOT activate because your only in one gear the entire time. There for even IF in some odd and strange way you could gain HP from it you wouldn't be able to see it on a dyno.

And for that same reason you can't gain HP from it. The valve only actives when the throttle is closed and if the throttle is closed your not making any power. When the throttle re-opens again the valve should be closed and your air flow is back to normal. The only factor in the whole deal is that it will dump some extra fuel on the pistons milliseconds after the valve opens and closes and thats gone before the throttle ever opens again.


And if there are any more questions on the issue you really should look into the whole BOV system. These are things you should know if you have a turbo'd car or are even thinking about making one.


Purpose of a Blow Off Valve:
Blowoff valves are used to prevent compressor surge. Compressor surge is a phenomenon that occurs when lifting off the throttle of a turbocharged car (with a non-existent or faulty bypass valve). When the throttle plate on a turbocharged engine closes, high pressure in the intake system has nowhere to go. It is forced to travel back to the turbocharger in the form of a pressure wave. This results in the wheel rapidly decreasing speed and stalling. The driver will notice a fluttering air sound.

 

Ok so i pulled up the dyno sheet's and you are correct it does not change hp. so i will retact my last statement. But it does effect the performance of the car and how fast the turbo will spool after shift's this time i looked that up and im not going to open mouth insert foot again lol.

 

On some occasions when in HIGH boost it can effect performance and spool up. Which is what i said in one of my previous posts.

But the real question here is... why does it effect spool up?

Well because under high amounts of boost your going to have really big injectors and when you have really big injectors your going to be dumping a hell of allot more fuel and this can sometimes foul out spark plugs and destroy the catalytic converter if you have one. And god forbid if you have a catalytic converter on your car and you mention anything about horsepower I'll straight up smack the **** out of you. Because them two words don't go together.... if you have one you can't have the other.

So in the end your still not going to have any issues VTA on your lancer. At least not until you start pushing 30psi and then you might have to swap to a 50 / 50 BOV. =)

 

The fueling really doesnt have anything to do with spool up. How well it vents and how close it is to the throttle body will determine how fast is continues to spin during a shift. The faster it spins, the faster the respool. So the ideal location is next to the TB and a valve big enough to properly vent the flow (not pressure based) all be it 25mm, 34mm, or 50mm.

As for cats, you can have a high hp car and a cat. A good cat will only decrease power of a 500whp by 5-10whp at most. The stock 1.8t fwd cats are HUGE and when made to 3" in/out (about 6" round) has only show about 5hp drop on a 500hp engine dyno

 

^i agree with him a good clean cat does not really rob that much power from a car. but if it is dirty it will.

 

^ You have some twisted views on car mechanics.

When your running a turbo car, the cat is your biggest killer for power. You usually want 3" pipe all the way back with the least amount of turbulence that you can get.

The first thing you do to a slow *** stock Evo is an Exhaust and a tune just so the thing is at least a little peppy.


And as for Cincy's response... your right. Spool up wasn't the right word for it, it was just stuck in my head from what 02Lancer said... But spool up can be effected... there's a whole nother set of variables in there for that and I'm not gona even try to explain that right now.

And as for cats.... the lancer cat is only 2" and your exhaust is ONLY as big as its smallest opening. So no mater how big the case is its still only a 2" cat. And running a turbo car on a 2" cat or even a cat at all when your TRYING to make power is stupid. And by the way... your not going to find any cars making 500whp with a stock cat on the car. The first mod you usually do to an evo is exhaust and test pipe.

And before anyone even trys to say it... Free Flow Cats are illegal and are technically not cats. They are resonators shaped like a cat to fool state inspectors.



P.S: And just to make this clear... this is not a pissing fight and i don't want it to turn into one. I'm just trying to explain how things work so that people are a little more educated on the subject. I didn't want people reading this post about BOV's and getting the wrong information. When i first read this post i was confused as hell... i was looking for something that didn't exist and come to find out it was just a bunch of gibber jabber. Someone should have stepped in and corrected this post long ago. It wasn't the VTA that was causing the man car to stall, it was his BOV.

 

Ok I just did this on OZ about an hour ago using a Greddy type rs knock off. No stalling issues, afr right where I want it. It would richen up slightly( like .5) for a quick moment then it was fine. The only this is, I can't pass 5psi now...

 

Probably because you are using a ****ty valve that works like well.... ****

 

i'd prefer performance over sound.

but my type S is loud for being recirculated, you get over it after a week.