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I received a PM asking about my boost mods, I thought I'd share the answer with the forum.
I have fitted a Turbotech manual boost controller as advertised here:
http://cgi.ebay.com.au/Turbotech-manual ... 240%3A1308
This boost valve is not a run-of-the-mill bleed valve that simply vents pressure from the wastegate hose. Instead, it contains a check valve (a steel ball that is forced down onto a seat by a spring).
Boost pressure enters through the bottom port of the controller and tries to push the ball off its seat. When there’s enough boost pressure for this to occur, boost air passes through and reaches the wastegate actuator. Boost pressure is then controlled.
The advantages of this approach may not seem obvious at first. But compared to a bleed, it offers potentially superior boost consistency across a range of ambient temperatures and in different gears.
This is because, unlike a bleed, this controller unit has some inbuilt intelligence. For example, in extremely hot conditions or in a low gear (where the engine will produce a relatively small volume of exhaust gas) the steel ball inside the valve body will stay closed as long as necessary until enough boost pressure is developed to lift it off its seat.
The opposite also applies in extremely cold conditions or in a high gear (where the engine will produce a relatively large volume of exhaust gas) the steel ball will lift off its seat as soon as there’s enough pressure to do so.
The Turbotech controller gives a very quick rate of boost rise due to the spring preload applied on the internal steel ball, Its impossible for any pressure to reach the wastegate actuator until there’s enough boost to lift the ball off its seat.
Installation is very straightforward. Simply install it between the compressor outlet and wastegate actuator. Peak boost pressure can be varied using an adjustment bolt and locking nut. Turning the bolt clockwise increases preload on the spring which means greater boost pressure is required to lift the ball off its seat.
A small hole in the valve body (called an "excess pressure valve") allows pressurised air to escape from between the controller and wastegate actuator following a boost event. This pressurised air would otherwise be trapped against the wastegate actuator and cause poor boost response.
With the exhaust fitted I found boost went up from 10psi (9.7 by the Toyota spec) to around 11psi and I was happy to add a couple more psi and still sleep at night sound in the knowledge the engine can live with it.
Some of the Surf guys are running up to 17psi but I would suggest that this is the limit for such a small turbo charger and pointless without adding more fuel.
At 13psi, with the little extra fuel the Dtronic tips in, I think the engine is well within its limits. With only an extra 2 psi the performance gain is small but definitely noticeable (and for $30 its great bang for your buck). When I get time I’ll run the Prado on the dyno and see what the result is.
Fit a boost and EGT (exhaust gas temperature) gauge before doing any modifications.
Mick
Hi Mick
I read in the intercooler post that you have a manual boost controller on your 1kz which is set to 13psi. From memory the standard boost on the 1kz is around 8-9psi.
I'm interested in this installation. Can you pass on any more info regarding what is involved in this mod and how effective it has been?
Like you, my 1kz has a dtronic and beaudesert exhaust but standard boost at present.
Many thanks
Mark
I read in the intercooler post that you have a manual boost controller on your 1kz which is set to 13psi. From memory the standard boost on the 1kz is around 8-9psi.
I'm interested in this installation. Can you pass on any more info regarding what is involved in this mod and how effective it has been?
Like you, my 1kz has a dtronic and beaudesert exhaust but standard boost at present.
Many thanks
Mark
I have fitted a Turbotech manual boost controller as advertised here:
http://cgi.ebay.com.au/Turbotech-manual ... 240%3A1308
This boost valve is not a run-of-the-mill bleed valve that simply vents pressure from the wastegate hose. Instead, it contains a check valve (a steel ball that is forced down onto a seat by a spring).
Boost pressure enters through the bottom port of the controller and tries to push the ball off its seat. When there’s enough boost pressure for this to occur, boost air passes through and reaches the wastegate actuator. Boost pressure is then controlled.
The advantages of this approach may not seem obvious at first. But compared to a bleed, it offers potentially superior boost consistency across a range of ambient temperatures and in different gears.
This is because, unlike a bleed, this controller unit has some inbuilt intelligence. For example, in extremely hot conditions or in a low gear (where the engine will produce a relatively small volume of exhaust gas) the steel ball inside the valve body will stay closed as long as necessary until enough boost pressure is developed to lift it off its seat.
The opposite also applies in extremely cold conditions or in a high gear (where the engine will produce a relatively large volume of exhaust gas) the steel ball will lift off its seat as soon as there’s enough pressure to do so.
The Turbotech controller gives a very quick rate of boost rise due to the spring preload applied on the internal steel ball, Its impossible for any pressure to reach the wastegate actuator until there’s enough boost to lift the ball off its seat.
Installation is very straightforward. Simply install it between the compressor outlet and wastegate actuator. Peak boost pressure can be varied using an adjustment bolt and locking nut. Turning the bolt clockwise increases preload on the spring which means greater boost pressure is required to lift the ball off its seat.
A small hole in the valve body (called an "excess pressure valve") allows pressurised air to escape from between the controller and wastegate actuator following a boost event. This pressurised air would otherwise be trapped against the wastegate actuator and cause poor boost response.
With the exhaust fitted I found boost went up from 10psi (9.7 by the Toyota spec) to around 11psi and I was happy to add a couple more psi and still sleep at night sound in the knowledge the engine can live with it.
Some of the Surf guys are running up to 17psi but I would suggest that this is the limit for such a small turbo charger and pointless without adding more fuel.
At 13psi, with the little extra fuel the Dtronic tips in, I think the engine is well within its limits. With only an extra 2 psi the performance gain is small but definitely noticeable (and for $30 its great bang for your buck). When I get time I’ll run the Prado on the dyno and see what the result is.
Fit a boost and EGT (exhaust gas temperature) gauge before doing any modifications.
Mick
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