Well after my recent M3 victory, I decided to play with a little more car. My buddy's STI just got a waste gate, boost controller, and blow off valve. I have no idea what they run stock, but after driving it a long time ago I can tell you they are FUN AS HELL to drive. I hear they do low 13's stock. Anyways the 1st race we have someone flag us on when to go. I take him out of the hole and start pulling car length after car length on him. He said he didnt launch it. So the 2nd time we raced he dumped that clutch nasty and jumped ahead, I had to play catch up, which I did, I kept pulling on him, and at around 70-80 I pulled away from him and let off. Those things catch some mad traction. From a roll he stayed next to me for a while, but i pulled away quite quickly. Basically they are good out of the hole, and you need a nice amount of power to catch up, otherwise depending on what they have done to them they are still quite quick for a 4 door car.
He ran an 8.5 before the boost controller in the 1/8. I run 8.7's but i peel out through 1st gear, i just got these nittos (555-R), and they REALLY do stick. Im lovin them!!! I'm wondering now what I will run with the Nittos. Keep in mind I also have a stall I need to put in (2500) im launching it now at 1000rpms, so that will be a nice upgrade to the car.

 

????

 

If that is what your buddy got then he is a noob and his car is misconfigured and slower. Everyone in the STi world that knows what they are doing will NOT get a blowoff valve. The stock valve is recirculating and feeds back into the intake. This is taken into account by the computer. Most aftermarket valves vent to atmosphere ... thus, they make the car run really rich between shifts and make it slower. The STi, of course, comes with a turbo. The VF39 Turbo on the STi has an internal wastegate. He didn't get a new one. Boost controllers are gay without engine management (IMHO).

Ask him if he visits the IWS board and get his screenname for me.

Tim

 

yep, unless he has it tuned to compensate for the BOV, he will run rich everytime it blows off LOL gonna cause some hesitation and afterfiring and possible idle problems i have heard

 

I'm sure that he DID get a new BOV, but I'm just as sure that it's also recirculating. Also, factory turbo cars don't need any extra engine management with a boost controller because the car knows how to take care of itself up to the point of fuel cut. On non-factory turbo cars it's a differnet story, but not one worth telling since they need engine management to run anyway.

 

Why would you even need a blow off valve if it just recirculates back into the intake.

 

Some turbo cars can get by with the stock bov such as 1G DSMs but others such as 2g DSMs have leaky plastic pieces of crap that can barely hold the 14 stock psi much less higher. An upgraded 2g BOV -does- give you a better sound even if it recirculates into the intake (as it should to avoid a big puff of black smoke among other problems due to the location of the MAFS at the front of the intake) Therefore upgrading the BOV from a 2G plastic BOV to an aftermarket or better a 1G dsm BOV does benefit performance to a point.

That said, on an STi, which is built for performance, I don't see the factory using a crappy BOV so I suppose I agree about not needing an upgraded BOV with basic mods.

 

I think he means, why would you even have a blow off valve at all if it just goes right back into the intake.

Is that what you meant?

 

I gave him the benefit of the doubt.

 

yeah, its recommended by alot of WRX/STI guys that the stock BOV is great... aftermarket ones only can cause more problems by making the car run rich at the moment it goes Pssshhhhhh. LOL

unless you compensate for that aftermarket BOV via tune, it isnt a great idea.

 

problem with that is even a factory turbo car, especially one thats been modded will benifit from a re-tune. especially with a mbc. the tune on a turbo car is not as mod friendly as a n/a car. lets say stock boost is 14 psi. turn it up to 18-19psi. Thar would require a signifigant increase in fuel, timing would be decreased, all of which may be out of the capabilities of the stock pcm. also, the use of supporting mods may be required. larger ingectors, and such. an inproperly tuned turbo motor can be very disasterous, damage can be almost immediate.
that is why matchin parts with the car and a tune with it is so important. if your friend is unaware of this, you should put the bug in his ear to do more research.