Another unconventional Theory..
 

the guy who slapped in my 1900cc 2ndary's 2day was raving about how
wastegates are a complete waste of money, saying why buy an expensive Garret 45mm (whatever) wastegate when a $100 Pop Off Valve will vent excess boost perfectly fine, (in combination with a normal BOV) further, he said that it would actually be BETTER b/c the venting would be quick (not a wastegate creeping open) so response back on the pedal would be better.

He said that Indy Cars run like this, and that Nizpro tune their cars this way. He was adamant that wastegates were an unneccessary automotive piece of jewellery.

Hey, don't yell at me, i am just posting up the info that all these weird performance car tuners that i meet in my travels pass on to me. I just thought you guys might like something new to pick holes in or shoot down.

Any validity to this theory?
It *would* be nice to know that you didn't have to spend a zillion dollars on a fancy wastegate....
tho what if that cheap pop-off valve fails...hmmm...

Thoughts?

Actually, I THINK that he is correct because I know that some of the real fast Honda's out there just dump the waste gate and shove the excess out without one. The reason that the waste gate is there is for emissions, I think. Without a waste gate you have exhaust just dumping into the air, which the EPA doesn't like very much!!


Jeff

the hondas you are talking about have a wastegate, it just dumps into the atmoshere instead or going into the exhasut.

without a wastegate using a popoff valve to controll boost you would overspeed your turbo and blow it to pieces. also the AFM would now work since it would be taking in way more air then the engine is getting. it would be like having a really bad boost leak all the time.

Not to be mean or anything but are you the same guy that told us about his mechanic who hated BOV's?
Same avatar, from australia also I believed.
:-D

You're right B430, I went and looked at them again, and they do have wastegates...sorry!!!


Jeff

Makes me wonder if you're a troller... :)

Wastegates slow the turbo down by bypassing some of the exhaust gases away from the turbo turbine section.&nbsp This is the SAFE way of dropping boost.

Now, if we go with a pop-off valve, this opens on the compressor side of the engine.&nbsp Once the pop-off valve opens, the turbo overspins due to the low to zero resistance on the compressor side of the engine.&nbsp Overspinning the turbo is bad.&nbsp Sure, you eliminate lag in between the shifts, but at the cost of possible killing the turbo?

In a race situation, a pop-off valve might be argued to be okay, but on the street, ONCE AGAIN, you're going to kill the turbo prematurely on the street...



-Ted

Nah, this is a different mechanic to the one the doesn't like BOV's.
That guy really does know his stuff. His workshop has a heap of 9 and 10 second cars, tho i think i'll still be keepin my BOV (sorry Vlad)
Vlad, if u r reading this, post yourself your anti-BOV theory. I can't explain it well enough!

The guy who is anti-wastegate is this other mob Precision Fuel Injection.
His theory all sounded OK, but as i thought, if it is such a good idea, why aren't the truly savvy people out there doing it?
His answer was that Nizpro don't run wastegates, and neither do IndyCars, but i don't know enough to validate or refute either of those "allegations"...

as i said, i'm just repeating what i'm told. i thought u guys might find it interesting, u never know...

like the BOV thing, it might sound OK, but i don't run a workshop where i can blithely reach for a replacement turbo if mine explodes due to an experiment etc, so i'll stick with the formula that the Gods (ie; Mazda) intended

just thought y'd be interested,
Perry Gehenna

just wonder, are the BOV guys 9 and 10 sec cars street driven? because you can get away with a lot if the engine only has to run 10 seconds at full throttle before being rebuilt.

Even in a race situation you wouldn't want to do it, because an overspinning turbo is out of its efficiency range and is making the air REALLY FREAKIN HOT. And indy cars run wastegates, they have boost controllers at a preset level hooked to them that are supplied by the race sanctioning body. At least they used to, I remember hearing about it while watching the indy 500 many years ago.

Actually CART cars run both WASTEGATES (WG) and BLOW OFF VALVES (BOV) The BOV is preset by Cart to LIMIT maximum boost - The teams adjust the WG to keep boost just below the preset BOV limit so they DO NOT POP the BOV (a BAD thing) and lose power and possibly damage their turbos