Upping The Boost What Else Is Needed

[geea]

I remember reading somewhere about people having to change the spring in the wastegate of the turbo or similar when increasing the boost. I was hoping for a bit more information on this and what else would need to be done to run 10-12psi of boost. What else would need to be considered at these boost levels. I'm aware of the need for bigger injectors and also a high flowing cat and exhaust. I think at this stage the valve springs could be an issue aswell, is the valve spring problem lessened by increasing the flow of the exhaust?

I look forward to the views of all the knowledgeable people out there.

Geea.

[Unigroup]

Here is a little list I’ve roughed up Geea

1) Larger exhaust system

2) Up-rated Boost control solenoid

3) Up-rated turbo charger waste gate poppet valve (aka flap)

4) Up-rated Waste gate diaphragm

5) Higher capacity Injectors

6) Higher capacity fuel pump

7) Up-rated inlet & exhaust valve springs

Removal of restriction inside crossover pipe on top of the cam cover. Get someone to machine out the internals or just ditch the whole lot for custom intercooler and all new plumbing.

[aps]

I remember reading somewhere about people having to change the spring in the wastegate of the turbo or similar when increasing the boost. I was hoping for a bit more information on this and what else would need to be done to run 10-12psi of boost. What else would need to be considered at these boost levels. I'm aware of the need for bigger injectors and also a high flowing cat and exhaust. I think at this stage the valve springs could be an issue aswell, is the valve spring problem lessened by increasing the flow of the exhaust?

I look forward to the views of all the knowledgeable people out there.

Geea.

geea, by the time you run 7 to 8 psi turbo pressure the stock injectors are out of capacity and need to be replaced with a larger multi orifice 4 valve style injectors. The valve springs will need to be replaced as the high exhaust back pressure can cause an engine miss in high load/rpm conditions. :banghead: Ideally it is best to replace the stock exhaust system and to remove the high exhaust B/P. This greatly reduces the high thermal load on the pistons, valves, and the entire cylinder head ....much better for long term engine life and reliability. Bottom line if you dont address the high back pressure issue, DON'T run an agressive boost strategy (10 to 12 psi of turbo pressure) if you want/need reliable engine operation. :lol: Otherwise the valves will be sad in 30,000 to 40,000 km, and the subsequent cylinder head overhaul will be a very expensive repair bill. :(

Peter

APS

[JB]

Removal of restriction inside crossover pipe on top of the cam cover. Get someone to machine out the internals or just ditch the whole lot for custom intercooler and all new plumbing.???

Unigroup, can you please describe what sort of restriction is placed inside the crossover, this is the first I have ever heard of this, especially in this forum.

Can it be removed by myself? What sort of response should we see from the car?

[geea]

Here is a little list I’ve roughed up Geea

2) Up-rated Boost control solenoid

3) Up-rated turbo charger waste gate poppet valve (aka flap)

4) Up-rated Waste gate diaphragm

7) Up-rated inlet & exhaust valve springs

Removal of restriction inside crossover pipe on top of the cam cover. Get someone to machine out the internals or just ditch the whole lot for custom intercooler and all new plumbing.

Hi Unigroup, with these points I have a few questions.

2) is this needed if a piggyback cpu is utilized?

3-4) Are these hard to install and what sort of costs would be involved?

This is the first I have heard of this how much is to be gained by doing this?

Thanks Geea.

[geea]

The valve springs will need to be replaced as the high exhaust back pressure can cause an engine miss in high load/rpm conditions. :banghead: Ideally it is best to replace the stock exhaust system and to remove the high exhaust B/P. This greatly reduces the high thermal load on the pistons, valves, and the entire cylinder head ....much better for long term engine life and reliability. Bottom line if you dont address the high back pressure issue, DON'T run an agressive boost strategy (10 to 12 psi of turbo pressure) if you want/need reliable engine operation. :lol: Otherwise the valves will be sad in 30,000 to 40,000 km, and the subsequent cylinder head overhaul will be a very expensive repair bill. :(

Peter

APS

Thanks Peter for yet more valueable information. If the back pressure issue is dealt with by modifying the exhaust, would the valve springs still need to be replaced or are they only stressed by the extra back pressure?

Thanks Geea.

[ms700]

I have heard about the wastegate actuator needing modifying or converting to a external unit altogether in anything over 10psi.

[aps]

Thanks Peter for yet more valueable information. If the back pressure issue is dealt with by modifying the exhaust, would the valve springs still need to be replaced or are they only stressed by the extra back pressure?

Thanks Geea.

If the total exhaust back pressure pre cat converter is zero at max power then you could most likely retain the stock valve springs up to approx 330 KW (flywheel power). This comment is based on the valves springs being in good condition and consistant/equal spring pressure.

If you intend going further than 300KW (flywheel) I would prefer to replace the valve springs as the cost is not that high for the added peace of mind. AS to changing the cast ford crossover duct this is not an issue until you reach quite high turbo pressure (over 12 psi) as most of ther pressure drop/loss is in the stock intercooler core and end tanks. :lol:

Peter

APS

[Unigroup]

JB

Inside the cast crossover housing is basically a built in restriction where the cross section of the two inter cooler pipes is noticeably smaller then the rest of the piping. You can’t “remove” it only machine it out or get rid of the whole section together. In fact it may even promote higher air velocity at low engine speed which is why I wouldn’t bother touching it, unless you were to operate the engine at a much higher boost pressure then stock.

Geea

2) The stock solenoid can only bleed a small amount of air and so for higher boost pressures will not be able to bypass enough air to fool the actuator ie. Lower boost then demanded. So even if you have a after market ECU delivering a 100% duty cycle command to the solenoid ie. Completely open, pneumatically it will only be to fool the stock actuator for a few more psi.

3)-4) The stock flap in its OEM application was designed to flow a certain amount of exhaust gas. Once you start to free up the restrictions built into the engine then the flap can’t bypass enough gas and you have cases of turbo charger over speeding ie. Over boost. To change the flap requires machining of the turbine housing which is best left to the professionals. The waste gate actuator is basically a technician’s job and can be done by you but requires the turbo be taken off the engine. Honestly I wouldn’t bother with it myself since the turbo shop could change the actuator and flap at the same time.

[trbo 6]

Geea

How are you running such fast times (13.322) if you havent already done these mods?