When is a blow off valve needed? Over 10 psi? 15? 20?...
- Thread starter fmaio
- Start date
On a street bike where you're constantly on and off the throttle it's a lot easier on the turbo to have on at any boost level.
Race only bikes you can get away with not having one, but still chopping the theottle at 30psi still puts a gun to your turbos head.
Race only bikes you can get away with not having one, but still chopping the theottle at 30psi still puts a gun to your turbos head.
Boosted is right. I ran a blow off valve from day one on my sled, as it would stop the turbo from chattering when on and off the throttle. Other guys did not, and had to replace bearings, while mine kept running solid. When I did my setup on the Busa I made sure I had one. I can hear it go off even with just slightly making boost and shifting.
Thanks for the feedback, which leads to more questions - I do not plan on running more than 10-12 lbs, maybe 15 later on, so what would you recommend as a good model to add? - And I would think it will need to be set up at a higher pressure level than the waste gate pressure, correct?
Tial and turbo smart are both great options. I have tials on all of my boosted vehicles.
And spring pressure needed for the BOV is directly dependent on how much vaccum your engine pulls at idle. Tial has a chart on their website. Basically the stronger the engine vaccum, the heavier the spring needed in the BOV.
Tial and turbo smart are both great options. I have tials on all of my boosted vehicles.
And spring pressure needed for the BOV is directly dependent on how much vaccum your engine pulls at idle. Tial has a chart on their website. Basically the stronger the engine vaccum, the heavier the spring needed in the BOV.
I did not think about vaccum, I will check the chart- Thanks, but another question: If the engine is making 10 psi and I close the throttle hard how much does it spike? What I am getting at is shouldn't the BOV have a higher psi rated spring than what my intended boost level should be? If not, would the BOV open before the WG? - I am still learning............
And spring pressure needed for the BOV is directly dependent on how much vaccum your engine pulls at idle. Tial has a chart on their website. Basically the stronger the engine vaccum, the heavier the spring needed in the BOV.
I did not think about vaccum, I will check the chart- Thanks, but another question: If the engine is making 10 psi and I close the throttle hard how much does it spike? What I am getting at is shouldn't the BOV have a higher psi rated spring than what my intended boost level should be? If not, would the BOV open before the WG? - I am still learning............
mysql
Registered
Biggest gain I had on my turbocharged car was adding a boost controller. It keeps the wastegate sealed till you hit the target then it opens up. With a spring, the wastegate slowly creeps open, which means spool time is not nearly as fast as with a boost controller because part of the air is bypassing the turbo prior to the target pressure being reached. It is a massive difference. You also get the added bonus of being able to dial up or down your boost with a single button click.
Kevin Jones
Registered
As I got my ass kicked time and time again at the track by the grudge bikes, I kept blaming it on the 15" swingarms and whatever excuse I could use and my bike at +8 couldnt launch like that. I never truly accepted the fact that they used progressive nitrous tuned by pros and COULD launch at factory hp and HIGH rpm and get a good 60'. So I stuck with my WG spring in denial and accepted my beatdowns, all, every single one, resulting from 60' deficiencies from no boost controller (and suspension which we could all use a little bit of tweaks on). I ran 1.4 60' with my busa stock easy peasy. Now I was at 1.8 at best, 2.0 many times. 50% of my launches were comical spins (well not funny really) or wheel up and throttle chop and the rest were only avoided by low rpm and clutch cooking. I looked around one day and saw the same set up on every bike that beat me. I was once beat by an r6 with 80hp nitrous shot. I was so mad I saw red. So I looked around at every bike around me. NS2 progressive nitrous. Why did I think a turbo would be any different? Why was I so stubborn? I dont know. But without a boost controller of some sort, your track times will suffer, even with a stage 1. Roll ons? Nobody has a chance. But I dont care about that. I like the track.
The spring in the BOV has absolutely nothing to do with boost pressure or gate springs. No it will not spike.
Tials usually come with the stiffer spring. Once the bike is built, get it running and warmed up good with a vac/boost gauge hooked up. Get your reading, and go in tials site, pull up the chart. Find the spring that all in range of your vacuum. But it, and install it. Never think about BOV springs again.
Kevin Jones
Registered
Haha, thats the sound I hear after doing a burnout. It sounds like its coming from the back tire though. Must just be the way it goes.
Similar threads
