Do you get compressor surge with your Tial???
I know Tial has a special spring they put in thier bov's for the rotary. With that spring do you guys still get compressor surge??? Did the spring help?
STEPHEN |
The new spring (free exchange from Tial) fixed the surge completely. Very satisfied...
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I still get it a little on light throttle lifts... but it seems to work pretty good overall.
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How does this spring fix work?
I get compressor surge (sound anyways) on my Greddy Type S no matter what spring tension, rpm or boost (except under high vacuum) when i release the accelerator. |
I use a turbo xs, i have never had any signs of cs, plus its very loud.
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So for you guys with the Tial running the no surge spring, does it have any effect on how much boost the Tial will hold??? I assume not but you never know. I think the problem was just that our cars dont run enough vacume to open the flapper cause its spring tension was to high so this is to help the lower vac engines like ours.
Is that correct??? STEPHEN |
Really the spring does not have to be any greater than the difference in pressure loss across the throttle plates to hold closed on boost, since it has boost applied to the top of the diaphragm as well as spring pressure , it operates on differential pressures not applied pressure...kind like this
p1=pressure in intake pipe before throttle plate p2=spring pressure p3=pressure in intake manifold after throttle plate so we have p1 loading against p2 and p3 on while accelerating. p1 =10 lbs of boost p2 = say a 5 lb spring p3 intake pressure minus losses across the throttle plate, so about 9.8 lbs.. Add it up and its 10 lbs in the intake pipe trying to open the valve against 14.8 psi on the diaphragm side.. The only thing that would throw that off is if you had a really poorly designed bov where the valve area is greater than the diahpragm area....If you had to keep the bov closed due running an AFM you would want the bov spring rated maybe 2" greater than your idle vaccuu, to keep it closed during idle, otherwise it would pull open and bypass the afm.. However on cars like my own, at idle the air travels through its own filter through the the bac valve, I really don't care if the bov hangs open at idle, it snaps shut as soon as the throttle plates are lifted... My post from Rotary performance.. I was one of the first guys with a rotary to use the Tial, I had alot of comunication with them over the bov, they were originally shipping it with a spring that cracked around 26 inhg, then they came with a lighter one that was about 18 in hg, I ended up have to make my own, that cracked at 9inhg, I forwarded them my spring info, and thats apparently what their new spring is based on.. One thing I have found with my car, is that in order to make the Tial work properly, and to get rid of surge, is to setup the closed throttle idle properly, a working back valve is a must with a tial, alot of guys with stand alone ems's skip the bac valve install, some ems's don't support it either, the wolf bac valve control is super shitty, and the microtech has to be pre configured hardware wise to use it, I have the haltech, which does allow bac valve control, but it has to be setup right, in the hitman and haltech manual it talks about setting the minimum idle on the throttle plate, and using the bac for idle up when a/c , or alternator load, drags the idle down, people without bac valve have to set the idle up a little higher than normal to compensate for alternator and a/c loading at idle, so that when the lights and electric fans come on, the motor doesn't stumble down and die. Its that little bit that the throttle plates are open that delays and weakens the vaccuum signal enough to make the tial not open fast enough, its a very large valve with alot of surface area, and it needs a good signal to crack early enough.. I strayed from the Hitman/haltech and pretty much took out the minimum idle stop on the throttle plates, got rid of the throttle delay pot thats on the throttle body(its a spring loaded plunger with a diaphragm that sucks through a small orifice that makes the car throttle down slowly to allow the stock computer to catch up to the changing fueling requirements under deaccel and get the bac valve open... So now my throttle pretty much just snaps 100% shut, and the bov is now alot more active than it used to be, even in light accelaration when I let off I get the psssshhttt, where as before even with a super light spring I would get the big turkey gobble effect, its important to get the settings right in the haltech for the bac valve, the bac valve can be setup so that the haltech controls the motor just like the stock setup, and make it act like it still has the deaccell vac pot, just by playing with the settings... I use 14 for a ms value. 32 for the steps, and minim open of 25% hot, and 75% hot opening.. The car behaves pretty good with these settings...max |
Originally posted by SPOautos So for you guys with the Tial running the no surge spring, does it have any effect on how much boost the Tial will hold??? I assume not but you never know. I think the problem was just that our cars dont run enough vacume to open the flapper cause its spring tension was to high so this is to help the lower vac engines like ours. Is that correct??? STEPHEN *Personally* I dont' think the engineering was quite finished on that BOV. Some changes to chamber sizes should be able to fix that. FWIW, I did have a turbo XS type Hbefore my TiAl... and it worked flawlessly. -Chris |
So why did you switch to the Tial???
STEPHEN |
Got a new IC and it's easier to sell an IC with a BOV than with a big hole in the pipe.
I figured it was a good time to "upgrade"... not sure that's the right word for it... |
I'm happy with my tial. No surge, no gimmicky whistling noise. Holds 15-17psi routinely and I have seen 19psi.
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I run 18-19psi on a daily basis, I was just wanting to know that with the weaker spring it was going to hold, that that the weaker spring was working for the surge. I think it'll probably be fine since it doesnt affect the closeing power.
STEPHEN |
Originally posted by carx7 FWIW, I did have a turbo XS type Hbefore my TiAl... and it worked flawlessly. -Chris |
I had a universal one for my FC.
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I'm glad I read this thread before purchasing one. It sounds like it still leaves some room for improvement. I'll guess I'll just go with an HKS instead.
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Originally posted by the_glass_man I'm glad I read this thread before purchasing one. It sounds like it still leaves some room for improvement. I'll guess I'll just go with an HKS instead. Nah, there really isnt anything wrong with it. When it first came out thier standard spring was to still cause most cars run more vacume than a streetported rotary. When they found out that thier standard spring was causing compressor surge for our cars they came up with a different spring for rotary engines. You just need to tell them its going on a rotary engine so you get the right spring. Other than that there shouldnt be any problems. I just wanted to make sure the revised spring wasnt causeing any other problems. STEPHEN |
Originally posted by SPOautos Nah, there really isnt anything wrong with it. When it first came out thier standard spring was to still cause most cars run more vacume than a streetported rotary. When they found out that thier standard spring was causing compressor surge for our cars they came up with a different spring for rotary engines. You just need to tell them its going on a rotary engine so you get the right spring. Other than that there shouldnt be any problems. I just wanted to make sure the revised spring wasnt causeing any other problems. STEPHEN |
The Turbo XS type H's are all over ebay as well and cheap as hell I might add. Anyone else have an opinion on those ? Carx7 seemed to run his with no problems.
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The ones off Ebay wont have the right spring but if you call Tial they will do an exchange with you.
STEPHEN |
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