Tial BOV
08-10-03, 04:41 PM
#1
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Tial BOV
anyone have any experience with these? I am thinking about getting one for my car. are the springs adjustable like other bovs for stiffness?
08-10-03, 11:27 PM
#4
It's a big BOV. I do not believe it's adjustable, however my guess would be various spring's would be available from Tial. I have been very impressed with the quality of all the Tial stuff I have seen, the BOV was no exception.
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08-11-03, 01:40 AM
#9
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It's not adjustable, but you can replace the spring. Otherwise, the quality is very good. I have one still in the box waiting for me to get off my rear end and install it into the intake piping of my 20B. I'm not sure if the lack of fine adjustment is going to be a problem or not, but I'm going to give it a try.
Note that a blow-off valve vents to the atmosphere, while a bypass valve vents back to the compressor intake. The stock RX-7 comes with a bypass valve so that no air escapes from the system after the AFM has measured it. If you install a blow-off valve that vents to the atmosphere, the stock ECU will run the engine rich upon the venting action because it thinks there is more air going to the engine than there really is, and it therefore injects the amout of fuel it thinks it needs for the large air mass that no longer exists. This fuel enrichment will cause the engine to bog or stumble. Most people don't care because they like the sound, but the car's 1/4 mile times will suffer slightly. An aftermarket EMS or fuel computer can fix this problem. GReddy and HKS make good bypass valves (they also work as BOV's if vented to the atmosphere) if you decide to go that route. TiAL was thinking about making a bypass adapter for their BOV, but I'm not sure if it ever made it to the marketplace or not.
Oh yeah, compare it to the cheapest BOV on the market, lol.
Note that a blow-off valve vents to the atmosphere, while a bypass valve vents back to the compressor intake. The stock RX-7 comes with a bypass valve so that no air escapes from the system after the AFM has measured it. If you install a blow-off valve that vents to the atmosphere, the stock ECU will run the engine rich upon the venting action because it thinks there is more air going to the engine than there really is, and it therefore injects the amout of fuel it thinks it needs for the large air mass that no longer exists. This fuel enrichment will cause the engine to bog or stumble. Most people don't care because they like the sound, but the car's 1/4 mile times will suffer slightly. An aftermarket EMS or fuel computer can fix this problem. GReddy and HKS make good bypass valves (they also work as BOV's if vented to the atmosphere) if you decide to go that route. TiAL was thinking about making a bypass adapter for their BOV, but I'm not sure if it ever made it to the marketplace or not.
Originally posted by Dan H
Tial BOV's are among the highest quality I've seen. At least compared to my Turbo XS RFL.
Tial BOV's are among the highest quality I've seen. At least compared to my Turbo XS RFL.
08-11-03, 02:01 AM
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Originally posted by rx7freddie
post a link where can i buy it ?
post a link where can i buy it ?
http://www.xtecheng.com/
08-11-03, 02:08 AM
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Originally posted by Evil Aviator
Oh yeah, compare it to the cheapest BOV on the market, lol.
Oh yeah, compare it to the cheapest BOV on the market, lol.
08-11-03, 01:17 PM
#13
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Tial is VERY high quality but I have found they are difficult to get. I'm using a Tial Wastegate and BOV and both of them took 2 months to get. They are polished though and look really good. American made also.
08-11-03, 01:18 PM
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Originally posted by TrboRty
so they will work with a car that boost only to 10 psi? so will I need to then get a spring that vents at 10psi?
so they will work with a car that boost only to 10 psi? so will I need to then get a spring that vents at 10psi?
https://www.rx7club.com/forum/showth...hreadid=112452
https://www.rx7club.com/forum/showth...hreadid=118171
08-11-03, 07:46 PM
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Originally posted by TrboRty
well how do i know which spring to get with it then?
well how do i know which spring to get with it then?
TiAL Products, Inc.
510 S. Washington Street, #16
P.O. Box 1019
Owosso, MI 48867
989-729-9973 (Fax)
E-mail: tialinc@earthlink.net
* Once you find out what they say, please post another thread here so we can archive it for others who have the same question.
08-11-03, 08:51 PM
#18
As an owner of a TiAl valve I should input here. As J-Rat said I really like the valve. The build quality is top notch
HOWEVER, I do not belive that it works totally correctly. I origionally purchased the valve and was given the wrong spring. They had a spring for a "piston" engine and for a "rotary" engine. The rotary being a bit liter since the vac reading is slightly less. Well, with the piston verson the valve didn't even open at 8-10 PSI boost. I had LOTS of compressor surge. (THree stooges whoob, whoob, whoob, whoob) I called and they sent me a rotary version. I still had surge although the valve did open "pshhhh" after some working. I checked and almost every other rotary person was expereincing the same. We all called Tial and Greg sent us even lighter springs. Now, my valve actually ocsillates at idle. I have a heavy street port and after a hard run where the idle is lightly bumping, you can see the valve oscilate open and closed. Fortuantely I have a Haltech so it's all good.
I still belive I have some compressor surge initially right when I lift of the throttle. I had a turboXS TYpe H when they origionally came it. It worked flawlessly. and was cheaper
Evil, I purchased my valve from xtecheng as well, and he said they only made one spring type, which I got, and was the "piston" version. You will definatley need to switch this out with TiAl or the valve won't work at all.
-Chris
HOWEVER, I do not belive that it works totally correctly. I origionally purchased the valve and was given the wrong spring. They had a spring for a "piston" engine and for a "rotary" engine. The rotary being a bit liter since the vac reading is slightly less. Well, with the piston verson the valve didn't even open at 8-10 PSI boost. I had LOTS of compressor surge. (THree stooges whoob, whoob, whoob, whoob) I called and they sent me a rotary version. I still had surge although the valve did open "pshhhh" after some working. I checked and almost every other rotary person was expereincing the same. We all called Tial and Greg sent us even lighter springs. Now, my valve actually ocsillates at idle. I have a heavy street port and after a hard run where the idle is lightly bumping, you can see the valve oscilate open and closed. Fortuantely I have a Haltech so it's all good.
I still belive I have some compressor surge initially right when I lift of the throttle. I had a turboXS TYpe H when they origionally came it. It worked flawlessly. and was cheaper
Evil, I purchased my valve from xtecheng as well, and he said they only made one spring type, which I got, and was the "piston" version. You will definatley need to switch this out with TiAl or the valve won't work at all.
-Chris
08-12-03, 08:41 AM
#20
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Originally posted by carx7
[B] Now, my valve actually ocsillates at idle. I have a heavy street port and after a hard run where the idle is lightly bumping, you can see the valve oscilate open and closed.[B]
[B] Now, my valve actually ocsillates at idle. I have a heavy street port and after a hard run where the idle is lightly bumping, you can see the valve oscilate open and closed.[B]
For my 20B project, I'm just going to start with the stock spring and work my way down. A little compressor surge isn't going to hurt anything, but valve float at idle is bad juju. BTW, my vacuum source is going to be much different than yours.
08-12-03, 10:09 AM
#22
You're right. I may just shim it as I'm not sure I want to deal with getting yet another spring from them. You're also correct that you have a different vac source 
This just goes to show that there is actually design work that needs to go into something like this. My personal belief is that the difference in surface area between the front and back of the valve is not great enough, which causes the problems.
It does sound cool when it vents, and I've only used it at ~10 psi. When I get my car going again in the next month or so I'll know how it performs under real boost from a real turbo.
This just goes to show that there is actually design work that needs to go into something like this. My personal belief is that the difference in surface area between the front and back of the valve is not great enough, which causes the problems.
It does sound cool when it vents, and I've only used it at ~10 psi. When I get my car going again in the next month or so I'll know how it performs under real boost from a real turbo.
08-13-03, 09:25 PM
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Originally posted by TrboRty
Another words, if you are running a stock s4 or s5 turbo, it's not worth the hassle of getting it.
Another words, if you are running a stock s4 or s5 turbo, it's not worth the hassle of getting it.
08-14-03, 09:43 AM
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I've got my tial sitting in my room waiting to get the flange welded on. I'm pretty sure it has the *piston* spring. So whats the deal? That spring is too stiff? At what vaccum reading should it start to open? Full open?
With a simple hand pump, you could bench test your valve and either shim the spring or take a dremel and start taking material off to lower the K value till you have it opening exactly where you want it to. It'll be a few hours worth of dicking around, but you should be able to make it perfect.
With a simple hand pump, you could bench test your valve and either shim the spring or take a dremel and start taking material off to lower the K value till you have it opening exactly where you want it to. It'll be a few hours worth of dicking around, but you should be able to make it perfect.
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