[Mk2] [Turbo] i want 300bhp ish :P

[GreddyMR2]

If you want the flutter. Take the bov off or block it off.

You will actually increase response between shifts, contrary to popular sponsored opinion.

Would you recommend it for track usage? Is it nothing wrong for the engine?

That is a very bad thing to do, the turbo will not like it and you could damage the comp wheel

What do you think about this article?
http://autospeed.com.au/cms/title_Nizpr ... ticle.html

[bobhatton]

Would you recommend it for track usage? Is it nothing wrong for the engine?

That is a very bad thing to do, the turbo will not like it and you could damage the comp wheel

What do you think about this article?
http://autospeed.com.au/cms/title_Nizpr ... ticle.html

Most of that to do with dump valves is wrong, he does not understand how they work

[Al-sw20]

How ever did Toyota get away with selling the ST185 GT-Four. They never had a blow off valve fitted. The ct26 doesn't fall apart any quicker on those.

Oh yeah and the Porsche 962, you know the one that won Le Mans? The ultimate test of reliability? No blow off valve.

Also countless other turbo charged race cars. No blow off valve.

What do you think about this article?
http://autospeed.com.au/cms/title_Nizpr ... ticle.html

Most of that to do with dump valves is wrong, he does not understand how they work

I think he knows a little more than you despite what your signature claims.

[bobhatton]

Lets see what Garrett have to say about the use of a bov

"The Blow-Off valve (BOV) is a pressure relief device on the intake tract to prevent the turbo’s compressor from going into surge. The BOV should be installed between the compressor discharge and the throttle body, preferably downstream of the charge air cooler (if equipped). When the throttle is closed rapidly, the airflow is quickly reduced, causing flow instability and pressure fluctuations. These rapidly cycling pressure fluctuations are the audible evidence of surge. Surge can eventually lead to thrust bearing failure due to the high loads associated with it.

Blow-Off valves use a combination of manifold pressure signal and spring force to detect when the throttle is closed. When the throttle is closed rapidly, the BOV vents boost in the intake tract to atmosphere to relieve the pressure; helping to eliminate the phenomenon of surge."

"Surge is the left hand boundary of the compressor map. Operation to the left of this line represents a region of flow instability. This region is characterized by mild flutter to wildly fluctuating boost and “barking” from the compressor. Continued operation within this region can lead to premature turbo failure due to heavy thrust loading.

Surge is most commonly experienced when one of two situations exist. The first and most damaging is surge under load. It can be an indication that your compressor is too large. Surge is also commonly experienced when the throttle is quickly closed after boosting. This occurs because mass flow is drastically reduced as the throttle is closed, but the turbo is still spinning and generating boost. This immediately drives the operating point to the far left of the compressor map, right into surge.


Surge will decay once the turbo speed finally slows enough to reduce the boost and move the operating point back into the stable region. This situation is commonly addressed by using a Blow-Off Valves (BOV) or bypass valve. A BOV functions to vent intake pressure to atmosphere so that the mass flow ramps down smoothly, keeping the compressor out of surge. In the case of a recirculating bypass valve, the airflow is recirculated back to the compressor inlet."

[bobhatton]

How ever did Toyota get away with selling the ST185 GT-Four. They never had a blow off valve fitted. The ct26 doesn't fall apart any quicker on those.

Oh yeah and the Porsche 962, you know the one that won Le Mans? The ultimate test of reliability? No blow off valve.

Also countless other turbo charged race cars. No blow off valve.

What do you think about this article?
http://autospeed.com.au/cms/title_Nizpr ... ticle.html

Most of that to do with dump valves is wrong, he does not understand how they work

I think he knows a little more than you despite what your signature claims.

Well you are wrong again

[BarronMR]

How ever did Toyota get away with selling the ST185 GT-Four. They never had a blow off valve fitted. The ct26 doesn't fall apart any quicker on those.

Oh yeah and the Porsche 962, you know the one that won Le Mans? The ultimate test of reliability? No blow off valve.

Also countless other turbo charged race cars. No blow off valve.

The Porsche 962 turbocharger will have an axial bearing systems designed to deal with the greater stress caused by surge. No valve due to performance loss.

As for the GT4 I would guess that due to the lower levels of boost (sub 10psi?), doesn't cause much stress in surge conditions. Toyota went to a recirculating valve in higher boost applications.

[Peter Gidden]

As for the GT4 I would guess that due to the lower levels of boost (sub 10psi?), doesn't cause much stress in surge conditions.

Correct. Same reason as Nobles, including mine, had no BOV as standard. Small turbos + 10psi boost.

[GreddyMR2]

So... There two opinions. But which is right? I am planning to block the bov for track day usage and open for daily driving. Would it be good idea? I will be using CT20 at about 1bar of boost.

[karlz0r]

So... There two opinions. But which is right? I am planning to block the bov for track day usage and open for daily driving. Would it be good idea? I will be using CT20 at about 1bar of boost.

why not just use the standard toyota recirc valve as it does the job as required its not weak, I dont see what benifited your going to get blocking it ?

[Super_red]

Would you recommend it for track usage? Is it nothing wrong for the engine?

That is a very bad thing to do, the turbo will not like it and you could damage the comp wheel

What do you think about this article?
http://autospeed.com.au/cms/title_Nizpr ... ticle.html

That article is garbage. A blow off valve and a recirculating valve are 2 different things. An air flow meter can be made to snap shut if the air flow is in the wrong direction, it does not read the air flow twice. Over fueling comes when a blow off valve is used with an air flow meter.

[Peter Gidden]

A blow off valve and a recirculating valve are 2 different things. An air flow meter can be made to snap shut if the air flow is in the wrong direction, it does not read the air flow twice. Over fueling comes when a blow off valve is used with an air flow meter.

Depends on interpretation of terminology. BOVs can be "vent to atmosphere" or "recirculating", i.e. dumped air is recirculated back into induction system. They both do the same thing - release pressurised air in front of TB.

[Turbonoz]

How ever did Toyota get away with selling the ST185 GT-Four. They never had a blow off valve fitted. The ct26 doesn't fall apart any quicker on those.

Oh yeah and the Porsche 962, you know the one that won Le Mans? The ultimate test of reliability? No blow off valve.

Also countless other turbo charged race cars. No blow off valve.

Most of that to do with dump valves is wrong, he does not understand how they work

I think he knows a little more than you despite what your signature claims.

Well you are wrong again

100% with Al-sw20 on this one.

I have run many turbos without dump valves, off-boost compressor surge is not damaging to the turbo insofar as it will damage a compressor wheel. There is no evidence to back this up, if there is please post it and I will gladly reappraise my views.

The article above is about HOT WIRE AFMs (see the 200SX S14, this gives it away), not the flap-type found in the MR2 engine bay. Air can, and does, flow back through the AFM and be "read twice" so to speak. Open up your eyes/mind people

Rather than type the following out again, here is a post I made on the SXOC years back:

Compressor stall/flutter/pigeon/whatever does not equal compressor surge. There are different scenarios that can cause surge, and also varying results and consequences. Therefore, it is a type of surge. Safe surge!

Surge in a lift-off situation arises due to instantaneously operating to the left of the surge line, (throttle closed: zero flow, increasing pressure) but in this scenario, reverse flow occurs until pressure in the system is equalised and the flow across the compressor blade is stabilised. There is no real-world reliability or performance issue with this, hence "pigeon" is fine. Some people refer to this as stall/chatter/flutter, whatever. Every turbo will experience this when the throttle is closed.

Surge under load is due to using a compresor too large for the application in question, i.e. an inherent design flaw or poor choice of component. The engine simply cannot ingest the amount of air that the compressor is forcing through the cylinders. At WOT, this is detrimental to your turbo, there is much higher flow instability. Once in surge, there's not a lot you can do, as lifting off compounds the problem by further reducing flow in the system to zero at an even higher pressure. Everyone knows & refers to this as 'surge', unlike 'lift-off surge'/chatter/flutter/pigeon. Surge under load can be avoided by using ported compressor housings to recirculate diverted flow and partially venting relief valves which operate during states of low flow. Very useful for BB turbochargers with large compressors and low boost thresholds, that would otherwise surge at low RPM, yet provide high pressure at high RPMs (BIG powahz).

Recirculating dump valves are fitted by manufacturers to keep things nice and quiet (along with resonator boxes and 90° bends in the AFM-turbo trunking), to keep the AFM outputs (where applicable) correct, and for emissions/environmental purposes. Keep everything recirculated in a closed system, be it redundant pressure produced by the turbo between outlet & closed throttle plate, spent exhaust gases (EGR) or fumes from blowby (PCV). As has been proven time & time again, just because a manufacturer fits something as OEM, it doesn't make it desirable when modifying, if you're not restricted by emissions regulations or when components start to wear. But you know this.

Edit:
Turbos I am running/have run with no BOV:

300zx: twin T25s @ 1.4 bar
MR2 Turbo: CT26 @ 1.2 bar; T78 @ 1.5 bar
GTiR: T28 @ 1.9 bar
S13: T70 @ 1.7 bar; ; T3/T4 @ 1.4 bar; T25@ 1.2 bar; T28 @ 1.4 bar; T3 @ 1.5 bar; TD06 20G @ 1.8 bar
Fiat Coupe: T3 @ 1.4 bar
Sapph Cosworth: T34 @ 1.3 bar
Fiat Uno Turbo: T2 @ 1.3 bar
R32 4dr GTR: twin HKS 2510s @ 1.4 bar

Probably more, too.

[bobhatton]

How ever did Toyota get away with selling the ST185 GT-Four. They never had a blow off valve fitted. The ct26 doesn't fall apart any quicker on those.

Oh yeah and the Porsche 962, you know the one that won Le Mans? The ultimate test of reliability? No blow off valve.

Also countless other turbo charged race cars. No blow off valve.



I think he knows a little more than you despite what your signature claims.

Well you are wrong again

100% with Al-sw20 on this one.

I have run many turbos without dump valves, off-boost compressor surge is not damaging to the turbo insofar as it will damage a compressor wheel. There is no evidence to back this up, if there is please post it and I will gladly reappraise my views.

The article above is about HOT WIRE AFMs (see the 200SX S14, this gives it away), not the flap-type found in the MR2 engine bay. Air can, and does, flow back through the AFM and be "read twice" so to speak. Open up your eyes/mind people

Rather than type the following out again, here is a post I made on the SXOC years back:

Compressor stall/flutter/pigeon/whatever does not equal compressor surge. There are different scenarios that can cause surge, and also varying results and consequences. Therefore, it is a type of surge. Safe surge!

Surge in a lift-off situation arises due to instantaneously operating to the left of the surge line, (throttle closed: zero flow, increasing pressure) but in this scenario, reverse flow occurs until pressure in the system is equalised and the flow across the compressor blade is stabilised. There is no real-world reliability or performance issue with this, hence "pigeon" is fine. Some people refer to this as stall/chatter/flutter, whatever. Every turbo will experience this when the throttle is closed.

Surge under load is due to using a compresor too large for the application in question, i.e. an inherent design flaw or poor choice of component. The engine simply cannot ingest the amount of air that the compressor is forcing through the cylinders. At WOT, this is detrimental to your turbo, there is much higher flow instability. Once in surge, there's not a lot you can do, as lifting off compounds the problem by further reducing flow in the system to zero at an even higher pressure. Everyone knows & refers to this as 'surge', unlike 'lift-off surge'/chatter/flutter/pigeon. Surge under load can be avoided by using ported compressor housings to recirculate diverted flow and partially venting relief valves which operate during states of low flow. Very useful for BB turbochargers with large compressors and low boost thresholds, that would otherwise surge at low RPM, yet provide high pressure at high RPMs (BIG powahz).

Recirculating dump valves are fitted by manufacturers to keep things nice and quiet (along with resonator boxes and 90° bends in the AFM-turbo trunking), to keep the AFM outputs (where applicable) correct, and for emissions/environmental purposes. Keep everything recirculated in a closed system, be it redundant pressure produced by the turbo between outlet & closed throttle plate, spent exhaust gases (EGR) or fumes from blowby (PCV). As has been proven time & time again, just because a manufacturer fits something as OEM, it doesn't make it desirable when modifying, if you're not restricted by emissions regulations or when components start to wear. But you know this.

Edit:
Turbos I am running/have run with no BOV:

300zx: twin T25s @ 1.4 bar
MR2 Turbo: CT26 @ 1.2 bar; T78 @ 1.5 bar
GTiR: T28 @ 1.9 bar
S13: T70 @ 1.7 bar; ; T3/T4 @ 1.4 bar; T25@ 1.2 bar; T28 @ 1.4 bar; T3 @ 1.5 bar; TD06 20G @ 1.8 bar
Fiat Coupe: T3 @ 1.4 bar
Sapph Cosworth: T34 @ 1.3 bar
Fiat Uno Turbo: T2 @ 1.3 bar
R32 4dr GTR: twin HKS 2510s @ 1.4 bar

Probably more, too.

So you think you know more than Garrett, dream on boy

[Turbonoz]

Well you are wrong again

100% with Al-sw20 on this one.

I have run many turbos without dump valves, off-boost compressor surge is not damaging to the turbo insofar as it will damage a compressor wheel. There is no evidence to back this up, if there is please post it and I will gladly reappraise my views.

The article above is about HOT WIRE AFMs (see the 200SX S14, this gives it away), not the flap-type found in the MR2 engine bay. Air can, and does, flow back through the AFM and be "read twice" so to speak. Open up your eyes/mind people

Rather than type the following out again, here is a post I made on the SXOC years back:

Compressor stall/flutter/pigeon/whatever does not equal compressor surge. There are different scenarios that can cause surge, and also varying results and consequences. Therefore, it is a type of surge. Safe surge!

Surge in a lift-off situation arises due to instantaneously operating to the left of the surge line, (throttle closed: zero flow, increasing pressure) but in this scenario, reverse flow occurs until pressure in the system is equalised and the flow across the compressor blade is stabilised. There is no real-world reliability or performance issue with this, hence "pigeon" is fine. Some people refer to this as stall/chatter/flutter, whatever. Every turbo will experience this when the throttle is closed.

Surge under load is due to using a compresor too large for the application in question, i.e. an inherent design flaw or poor choice of component. The engine simply cannot ingest the amount of air that the compressor is forcing through the cylinders. At WOT, this is detrimental to your turbo, there is much higher flow instability. Once in surge, there's not a lot you can do, as lifting off compounds the problem by further reducing flow in the system to zero at an even higher pressure. Everyone knows & refers to this as 'surge', unlike 'lift-off surge'/chatter/flutter/pigeon. Surge under load can be avoided by using ported compressor housings to recirculate diverted flow and partially venting relief valves which operate during states of low flow. Very useful for BB turbochargers with large compressors and low boost thresholds, that would otherwise surge at low RPM, yet provide high pressure at high RPMs (BIG powahz).

Recirculating dump valves are fitted by manufacturers to keep things nice and quiet (along with resonator boxes and 90° bends in the AFM-turbo trunking), to keep the AFM outputs (where applicable) correct, and for emissions/environmental purposes. Keep everything recirculated in a closed system, be it redundant pressure produced by the turbo between outlet & closed throttle plate, spent exhaust gases (EGR) or fumes from blowby (PCV). As has been proven time & time again, just because a manufacturer fits something as OEM, it doesn't make it desirable when modifying, if you're not restricted by emissions regulations or when components start to wear. But you know this.

Edit:
Turbos I am running/have run with no BOV:

300zx: twin T25s @ 1.4 bar
MR2 Turbo: CT26 @ 1.2 bar; T78 @ 1.5 bar
GTiR: T28 @ 1.9 bar
S13: T70 @ 1.7 bar; ; T3/T4 @ 1.4 bar; T25@ 1.2 bar; T28 @ 1.4 bar; T3 @ 1.5 bar; TD06 20G @ 1.8 bar
Fiat Coupe: T3 @ 1.4 bar
Sapph Cosworth: T34 @ 1.3 bar
Fiat Uno Turbo: T2 @ 1.3 bar
R32 4dr GTR: twin HKS 2510s @ 1.4 bar

Probably more, too.

So you think you know more than Garrett, dream on boy

I'm no "boy" you muppet. I don't have to cut & paste from a website that need to consider how to get out of a warranty claim when their turbos xxxx themselves. No BOV = Garrett Warranty Null & Void. Wake up. Where is the PROOF? That's all I asked for

"Continued operation within this region can lead to premature turbo failure due to heavy thrust loading". Please explain to me when this occurs. Hint: It's got feck all to do with dump valves...

Keep the insults to yourself old man

[bobhatton]

So... There two opinions. But which is right? I am planning to block the bov for track day usage and open for daily driving. Would it be good idea? I will be using CT20 at about 1bar of boost.

The CT20B is not as strong as the CT26 so I would not block the BOV just use it as designed.

If you had a drage race car and were flat shifting then no need for a BOV but just for a track day why bother to change from stock?

[GreddyMR2]

So... There two opinions. But which is right? I am planning to block the bov for track day usage and open for daily driving. Would it be good idea? I will be using CT20 at about 1bar of boost.

If you had a drage race car and were flat shifting then no need for a BOV but just for a track day why bother to change from stock?

Because every second counts But, if it's dangerous, I will keep out of this.

[bobhatton]

So... There two opinions. But which is right? I am planning to block the bov for track day usage and open for daily driving. Would it be good idea? I will be using CT20 at about 1bar of boost.

If you had a drage race car and were flat shifting then no need for a BOV but just for a track day why bother to change from stock?

Because every second counts But, if it's dangerous, I will keep out of this.

Its not going to be dangerous but could cost money if the turbo has lots of miles on it.

Very good tyres are what are needed for track days together with top grade of fuel and some octaine booster. Also check your timing is no greater that 10 deg btdc

[Turbonoz]

If you want the flutter. Take the bov off or block it off.

You will actually increase response between shifts, contrary to popular sponsored opinion.

Would you recommend it for track usage? Is it nothing wrong for the engine?

That is a very bad thing to do, the turbo will not like it and you could damage the comp wheel

If you had a drage race car and were flat shifting then no need for a BOV but just for a track day why bother to change from stock?

Because every second counts But, if it's dangerous, I will keep out of this.

Its not going to be dangerous but could cost money if the turbo has lots of miles on it.

WTF?? How many people/personalities are posting under your username

All good fun

[dylan5084]

so back to the rev 3 sensors i need:-

rev 3 igniter, map sensor, what else?

is it easier/cheaper to just splice the rev 2 wiring and keep the rev 2 alternator?

can i use current sensors and upgrade the ecu or do i still need the rev 3 sensors with upgraded ecu?

[gazrev1tubby]

Rev2 - Rev3 conversion parts :

Rev3 injectors
Rev3 ecu
Rev3 engine loom - not essential, but much easier
Rev3 igniter
Rev3 injector resistor pack
Air intake temp sensor
Mass air temp sensor
Map sensor
4 wire lambda sensor

Fitting a bored out rail isn't a bad idea, and you'll also need an adaptor plate to allow the mat sensor to fit where the cold start injector currently is - gts chris sells these.

I believe the chassis loom connections are the same rev2-3, but the rev1 is different and will need wiring adjustments. The ecu wiring diagrams can be found at www.2bartuning.com

You may need to swap the alternator plugs on the looms, depending on whether yours is round or oval type, and you may need to swap the oil pressure sensors or loom plug, as the early ones had a spade type connector - whereas the rev3 has a 'proper' plug in type.

Pretty sure that covers it :th: