Outer Limits 4x4 Board

foad wrote:Correct me if I am wrong (I have never owned a diesel), but the blow off valve on a petrol engine opens when the throttle is snapped shut (under vaccum), it is only really there so the gasses from the turbo are kept flowing and as a result, the turbine does not slow down.

When you get back on the gas, the turbo is already "spooled", and it's back pumping.

From what I have been led to beleive, diesel's don't have a throttle plate, and hence the turbo is never slowed down, so there is no point to having one on a diesel.

edit: beaten to the post !

Gribble wrote:

foad wrote:Correct me if I am wrong (I have never owned a diesel), but the blow off valve on a petrol engine opens when the throttle is snapped shut (under vaccum), it is only really there so the gasses from the turbo are kept flowing and as a result, the turbine does not slow down.

When you get back on the gas, the turbo is already "spooled", and it's back pumping.

From what I have been led to beleive, diesel's don't have a throttle plate, and hence the turbo is never slowed down, so there is no point to having one on a diesel.

edit: beaten to the post !

That's sorta true, but it's only if you are running BIG boost and snapping the throttle shut hard.

Low boost running no blow off valve is okay, some factory turbo's don't come with a BOV for that reason, but they feel like shit once you start turning the boost up.

Thats half the idea, also on a petrol engine when the throttle shuts you get a pulse wave that travels back down the pipes and rapidly slows the turboshaft. Too much of it can root your turbo. But like you said it doesn't matter on a diesel because there is no throttle.

But if you want to run a blow off valve just to say;

HI LOOK AT ME I GOT A TURBO AND BLOW OFF VALVE ON MY CAR, HOW SIK AM I?

... then there is a way to do it. But because of its Grimace im not going to explain. Plus im going to the pub.

mickyd555 wrote:this might be off topic, but what is the noise that a semi makes, kinda sounds like a blow off, but more of a whislte than a "choooo"...........

Patroldude wrote:Hell - if you gonna trbo a petty motor people n really want a distinctive noise from turbo - do what ford did in the turbo sierra's... weld the waste gate up.

Makes a nice bang noise after 1.5 laps..... It killed motor real quick, but heck they got fastest lap time did they not most the time?
They would rebiuild it for next time - all good if you could afford it.

I recon the straight pipe with no muffleres sounds sweeeeet.

Mk

mickyd555 wrote:this might be off topic, but what is the noise that a semi makes, kinda sounds like a blow off, but more of a whislte than a "choooo"...........

mickyd555 wrote:ok, now im really confused, i thoguht a wastegate was a blow off valve??


can you tell i know nothing about turbos.........

bigpat wrote:The function of a wastegate is to regulate the amount of exhaust gas that enters the exhaust housing of the turbo. This limits the turbo RPM, which ultimately limits thee boost. 90% of applications use an 'internal' 'gate, while the serious performance boys use an external 'gate.

As above, the BOV helps prevent flow reversion and compressor stall.

Flutter is noticed with intercooler installed. My friends SURF does it. Intercooler core is like a big sound tube.

The loud whistle from trucks is simply the turbo spooling up under 60 psi of boost!, which also results in a cool ( & loud) flutter noise on gear change!

carts wrote:Well Sam, tomorrow morning i am fitting a BOV to the 60 series. It will be a plumb back job as opposed to a fully sik pssst sounding one.

Since I intercooled the 60 with that huge front mount, the compressor surge has become huge. Running 12psi of boost, compressor surge hits 16-17psi according to the gauge, not good for the old turbo.

Since it has a throttle butterfly, the BOV will work as a vacuum is created in the intake manifold upon deceleration.

I'll let you know how it goes.

mickyd555 wrote:this might be off topic, but what is the noise that a semi makes, kinda sounds like a blow off, but more of a whislte than a "choooo"...........

droopypete wrote:

mickyd555 wrote:this might be off topic, but what is the noise that a semi makes, kinda sounds like a blow off, but more of a whislte than a "choooo"...........

It is a scientifically proven fact that the combination of Coke a Cola, amphetamines and hamburgers results in uncontrolable flatulence a condition which is exaserbated by a high body fat coefficient and low IQ.

The noise you hear from the truck, is the driver "letting one rip", and the reason that some trucks make this noise and some don't, is that some of the smarter operaters have installed "reticulated methane injection systems" in their trucks, using a bell shaped intake made from Teflon coated titanium installed in the seat that channels the recycled methane into the intercooler where it's temp is reduced to 50c it then follows the same path as the regular air charge, making a "super mega mix" of oxygen/methane which results in an average 12.7% H/P gain, that is why you regularly see truck drivers drinking Coke and eating hamburgers when asscending a steep grade, they are quite simply riching up the mix, sadly, it also explains why they are always on their own.

A negative side to the "reticulated methane injection system" is that the methane is so volitile, all plumbing must be made from Teflon coated titanium and the seals are constucted of uranium depleted polystyrene and must be replaced after 5000 liters of Coke (or about 10 days) and mechanics must wear a full protection body suit (with respirator).

I hope this helps.
Peter.

Gribble wrote:

foad wrote:Correct me if I am wrong (I have never owned a diesel), but the blow off valve on a petrol engine opens when the throttle is snapped shut (under vaccum), it is only really there so the gasses from the turbo are kept flowing and as a result, the turbine does not slow down.

When you get back on the gas, the turbo is already "spooled", and it's back pumping.

From what I have been led to beleive, diesel's don't have a throttle plate, and hence the turbo is never slowed down, so there is no point to having one on a diesel.

edit: beaten to the post !

Thats half the idea, also on a petrol engine when the throttle shuts you get a pulse wave that travels back down the pipes and rapidly slows the turboshaft. Too much of it can root your turbo. But like you said it doesn't matter on a diesel because there is no throttle.

But if you want to run a blow off valve just to say;

HI LOOK AT ME I GOT A TURBO AND BLOW OFF VALVE ON MY CAR, HOW SIK AM I?

... then there is a way to do it. But because of its Grimace im not going to explain. Plus im going to the pub.

stumped wrote:

droopypete wrote:

mickyd555 wrote:this might be off topic, but what is the noise that a semi makes, kinda sounds like a blow off, but more of a whislte than a "choooo"...........

It is a scientifically proven fact that the combination of Coke a Cola, amphetamines and hamburgers results in uncontrolable flatulence a condition which is exaserbated by a high body fat coefficient and low IQ.

The noise you hear from the truck, is the driver "letting one rip", and the reason that some trucks make this noise and some don't, is that some of the smarter operaters have installed "reticulated methane injection systems" in their trucks, using a bell shaped intake made from Teflon coated titanium installed in the seat that channels the recycled methane into the intercooler where it's temp is reduced to 50c it then follows the same path as the regular air charge, making a "super mega mix" of oxygen/methane which results in an average 12.7% H/P gain, that is why you regularly see truck drivers drinking Coke and eating hamburgers when asscending a steep grade, they are quite simply riching up the mix, sadly, it also explains why they are always on their own.

A negative side to the "reticulated methane injection system" is that the methane is so volitile, all plumbing must be made from Teflon coated titanium and the seals are constucted of uranium depleted polystyrene and must be replaced after 5000 liters of Coke (or about 10 days) and mechanics must wear a full protection body suit (with respirator).

I hope this helps.
Peter.

awesome i was thinking it was 'bout time for another episide of Dr Pete