I know a few racers who don't use BOVs on big hp setups.
One told me every time he chops the throttle or feathers the gas, the turbo is right where he left it.
Besides chancing the throttle plate breaking off, that can be welded in.. What are the cons? I don't see any damage at all on these turbos with no BOVs. The price of going faster vs rebuild?

And why do we do burnouts right outside the water box? Has anybody tried starting theirs right at the starting line and laying down a few feet of rubber? I mean, it'll leave fresh rubber down and heat up the pavement---thus making for better traction at the launch.


What am i missing here?

 

Are you talking before or behind? You don't want to drag water up to the line with you, people who sit in the water box and then just roll out, are dragging water up to the line.. both a safety and traction issue..

 

The track isn't prepped behind the starting line which allows easier burnout instead of hooking. The water would also be little to non existent if you rolled through the box and up to the line. Doing a burnout from the line will also result in more clean ups at the starting line as apposed to behind the starting line (referring to breakage during burnout)

 

well.. what if you do a burnout a couple feet before the start, and drag the burnout out about 10 feet?

 

Rwd cars do this now. However, there could be a problem if you broke something during the initial hit and carried it over the starting line leaking. Leaves the possibility for more thorough clean ups and down time. Just my opinion

 

There use to be a rule about the FWD cars not being allowed to break the beams while doing a burnout. You had to stop before the tree. It was around the Sony Xplod/NOPI days. Someone correct me if I'm wrong.

 

It is still a rule and has been for 20-30 years. Not only for FWD cars but any car that isn't a PRO can not burnout past the starting line.

 

interesting.. what about my BOV question? if you didn't have a BOV you don't have to re-pressurize the charging pipes. It "may cause some damage" to the turbo, but insufficient cool downs also do.. i also know of plenty diesel trucks that get turbo flutter often and they have surpassed the 100k mark, drive them hard and everything seems fine..

 

Because Woooo-ppshhhhhhh sounds better than tchk tchk tchk tchk tchk tchk

 

Winner winner chicken dinner!

99% of us are frowned upon for doing so. And rightly so. Most of our cars don't pick up THAT much speed during a burnout that we cannot stop. This isn't Top Fuel. :p

 

Diesels don't have throttle bodies.

 

I'm auto so I don't get to hear the cool "pssshhhh" noise until I let off at the end of a run.

 

maybe someone should invent an electronic BOV to be controlled by the ECU...

 

this thread is over with

 

compressor surge is not good for the turbo.

Its also really common in the buick v6 turbo world to not run BOVs and they deal with the same thing.

 

I like to put BOV on every turbo car I work on even autos. It helps with turbo longevity and spool when pedaling.


Many years ago I installed a bigger bov and picked up 3 tenths... It helped spooling the turbo lifting to shift.

 

Really? I find that extremely interesting. I see both sides of this spectrum on different extremely fast cars.

I see 7 sec rotary cars running two BOVs

I saw the new Merman RWD car has no BOV at all

So which is more beneficial?

 

Having no BOV will cause a HUGE pressure spike when you chop the throttle and can cause distortions in the compressor wheel and damage it in a very short period of time. It can also bend the throttle plates. That huge pressure spike when you chop the throttle can actually slow down the turbo between shifts. Usually the guys not running BOVs are not lifting during the shifts and either shift against the limiter or have a dog box/strain gauge setup. I think the idea of not running a BOV is more to prevent any possibility of boost leaks. If you are going to chop the throttle between shifts, you need a BOV. On cars with larger turbos you will need more than one to maximize the effectiveness. The less load on the compressor when the throttle closes the less momentum it will loose between shifts. Also, making sure you have the proper spring in it can make a big difference. Having too stiff a spring can cause an ever so slight delay in BOV response time leading to some lost turbo momentum.

 

Throttle plate should stay open until you pull the Chute, so you can make an argument either way as it shouldn't affect you. Seems like it would be easy on parts to have one.

We already have glass $10,000 transmissions. Lets keep the burnouts back where the track won't rip stuff apart Our cars don't put down much rubber anyway, and we also don't need to do huge burnouts. If the track temp is 80 you don't want 110 degree rubber...if the track is 110, you don't want 80 degree rubber.

 

If you are able to do a burnout at the starting line, than either the track sucks, or your setup is way off. Most of the fast RWD cars do burnouts past the starting line anyways, but start in the water box to get the tires spinning.

If I didn't run a BOV I'd be replacing bend throttle blades every pass. And probably turbo components every other race.

 

good imput.. i guess little tricks from other platform cars don't work forus little 4 bangers :p

 

speaking of tire temp. what's a general rule of thumb for temp on a m&h or MT slick?

 

Depends on the track temperature.

 

was also wondering about this

 

bryson if you wanna hook you need to get an allignment that doesnt have 3 degrees of - camber lol