Fourdoor

iTrader: (11)

Hey guys,

I have noticed that with the stock spring in the TIAL BOV, I get some compressor surge when I come off the loud pedal from a part throttle condition. So, I called up Buschur Racing and they sold me the two other springs that are optional for the Tial BOV. The stock spring is 11 lbs per inch of compression (not 11 psi, these springs are measured just like the springs for your suspension). The first spring I tried was 9 lbs per inch and the last one was 7 lbs per inch. If you are still using a MAS setup, you need the 9 lb per inch spring because it keeps the BOV closed at idle for good idle quality when venting to atmosphere. Since I am converted over to speed density I am using the 7 lb spring and loving it!

I highly recomend this spring swap to anyone with a tial BOV. I would love to get a little vacuum pump with a guage and check each spring. I may do that in the future, but it is sort of a pain in the a$$ to swap them out.... so don't count on it

Keith

evo81

iTrader: (30)

good to know.tial bov is on the way.thanks for posting Fourdoor

FlyNavy

iTrader: (10)

I was just talking about this a couple minutes ago. How much boost are you running and does it hold just as well as the heavy spring? I've got the rattlesnake fluttering sound from the intake. Its annoying but seems to run fine. (speed density) I was warned third hand by turbo trix who tuned it that a lighter spring wouldn't hold boost as well. Was it an easy swap?

https://www.evolutionm.net/forums/sh...d.php?t=103859

Fourdoor

iTrader: (11)

The swap is real simple, but you have to be carful when pulling the last bolt out because that is a LOT of spring tension with the stock spring.

The upper chamber of the BOV has a larger surface area than the surface area of the popet valve itself, so when you are under boost you have more pounds of force pushing the valve shut than you have trying to force it open even if you had no spring at all ( the same pounds per square inch over a larger number of square inches). As soon as you go WOT the vacuum holding the valve open goes away and the spring forces it shut, then when you build boost the positive pressure in the intake manifold seals the valve tight.

I have data logs from before and after the spring swap, and I have the same boost spike and tapper as I did before, with peak boost of 23 psi. No leaks!

Keith

PS: Speed density huh? You running AEM EMS? I just ordered the GM boost control solenoid because I am tired of the "spike and tapper" behavior of manual controlers.

FlyNavy

iTrader: (10)

I'm excited to try the spring. I'll call Buschur tommorow and order it, or maybe both. How much $?

Yes I'm running AEM EMS tuned by Turbotrix. I haven't tweaked it myself, they're the experts. I'm running a manual boost controller right now. Whats up with the GM part? The car holds boost great at WOT up to 4th. WOT in 5th is a schizophrenic nightmare. Boost bounces around at reduced levels, shakes and does all kind of wacky stuff. Part throttle in any gear is a little unpredicable also, and cold idle with the ac compressor on needs a little gas to stay alive. I know the tune is quirky, but i don't want to mess with it because the WOT map is so badass. If TT couldn't tune it out I doubt I can. If nothing else I hope I can get rid of the comp surge. It was also tuned for 94 and I'm running 92-3.

ASTROEVO

iTrader: (2)

WOW.....i have been running the tia for a while now on my car.... speed density....might try this...but i am running alot of boost...let me know how it works

Fourdoor

iTrader: (11)

About BOV springs: The springs are $40 each plus shipping. The 9 psi spring is the white spring, the 7 psi spring is the black spring. I am sticking with the black spring myself. If you want to try the white one (mine is brand new) I would sell it to you cheap.... but in reality I recomend the black spring since you are speed density.

About boost control: Using a manual boost controler, you are probably getting a spike and tapper just like everyone else.... do some data logging with the EMS and you will see it much easier than you will notice it on a boost gauge. I am not sure why you are getting strange responses in 5th, that is just messed up! Using the GM boost control solenoid you can set your AEM EMS to operate as an electronic boost controler.

About cold idle tune: With HKS 272 cams, Tym over at Buschur Racing did an awesom job with the cold start and warm up maps, only thing I had to do to make it perfect was adjust the base idle set screw. That may be enough to fix your problem as well. No problems with AC on or anything! The WOT maps were also great for a base map. The daily driving portion of the map was way rich though. I have it tuned great now thanks to having the built in UEGO wide band. Talk to Turbo Trix if adjusting the base idle set screw dosn't help, and I am sure they can help you out. You really need to get the 5th gear strange boost behavior worked out though.... that could be a problem!

Later,

Keith

Fourdoor

iTrader: (11)

With the lightest spring (black 7 lb spring) I have no more and no less boost tapper than I had with the stock 11 lb spring (my tapper is due to 272 cams with stock turbo) and zero boost leakage at 23 psi. This results in ZERO compressor surge and the BOV is open at idle. At idle a very small amout of air is comming OUT of the upper IC pipe so I wouldn't be consurned about unfiltered air getting into the engine through the BOV.

For anyone reading this who is still running a MAS, using the 9 lb spring (white spring) will leave the BOV closed at idle for better idle caracteristics with a MAS.... but you do still have some compressor surge. Not as much, but you still have some. Oh, and of course with a MAS you will go rich when shifting due to venting to atmosphere.

Later,

Keith

evo81

iTrader: (30)

so is it ok to run a tial with mas?a flash should help with the running rich with a vta bov?i'm still getting this bov even if it has a little compressor surge.

Fourdoor

iTrader: (11)

As I said, if I were running with a MAS I would either switch to the white 9 lb spring, or possibly use the black 7 lb spring with some washers to shim it to the point that it just barely stays closed at idle. I think I will expieriment with that myself just for grins With that MAS you will have the normal problems associated with being vent to atmoshpere with any BOV.

Later,

Keith

Grod101

iTrader: (7)

If you are running a mas I wouldn't be using a VTA bov.... your car does not run correctly.... You are running super rich when you do that.... the air is measured at the MAS and that is how the fuel is calculated... so if you dump air out after then you are flooding it with fuel which ='s poor performance and will also foul up your plugs quicker... and just isn't good for the car... The tial is ment for running a standalone...NOT MAS.... also the Tial BOV is rated for up to 35 PSI.....

Fourdoor

iTrader: (11)

I agree 100% that running vent to atmosphere on a BOV isn't a good thing to do with a car that is still running a MAS. I just wanted to point out (for the 100's perhaps 1000's that do this) that going to the lightest spring would be a bad thing for them to do

Keith

FlyNavy

iTrader: (10)

Whats the advantage for us standalone guys keeping it closed at idle? I just ordered the black spring and am curious why it would benefit to washer it closed. Will this affect its performance in other regimes?

Fourdoor

iTrader: (11)

Nope. I can't think of any performance reason for it. I just like the look of it closed when the hood is open with the engine running

Keith

FlyNavy

iTrader: (10)

Gotcha. Thats as good a reason as any for a car guy. I spent the better part of Saturday afternoon making all my dash and internal lights red. HP gain=0.

BR said it'd take them a week or so to order the part, I can't wait to try it. Now that I know what that flutter is I notice surging all the time even when romping on it.