using low boost on 14b, problems?

[fr33b1rth]

if i used a 14b turbo for my 4g37 (1.8) and ran 4-5PSI boost, would i have a lot of problems with boost creep because the wasegate would be open quite a bit, or am i crazy?

 

[T9S1i]

the wastegate spring on a 14b is set at 10lbs of boost... if you are running 4-5 lbs of boost on a boost controller than theoretically your wastegate should never open... i was running my car on just the spring and 10 lbs while i had serious boost creep... it would hold at 10 then creep to almost 20... if you dont boost past 10 then you should be all good because creep doesnt happen unless the wg passage is over flown thus causing the exhaust wheel to spin more and thus making the boost creep up passed the set level so if you arent outflowing the wastegate passage you wont creep...

good luck with the turbo setup
happy boostin

danny

 

[crankbender]

sigh....the above post has some serious problems with it.

You can NOT produce less boost than the minimum that will open the wastegate unless you have a problem. Turbos are feedback controlled devices and the lowest pressure that can be controlled is the pressure at which the wastegate starts to open. Now you may be able to adjust the wastegate...that I can't say as it is based on your mechanical ability and such...not done often so eh.

 

[fr33b1rth]

yeah, that post isn't right. the wastegate is what controlly the bypass of exhaust gasses around the exhaust turbine. the faster the turbine spins (the more gasses that go through it) the more boost is produced. running lower boost will cause the wastegate to open more because more exhaust gas will need to bypass the turbine to slow it down. so in other words, without modifing the wastegate, i won't even be able to run below whatever psi the wastegate is set at without modifing it.

Are there any good turbos that are small that require use of an external wastegate?

 

[SpoOLxExO]

I ran my HKS wastegate setup off the #1 runner of my 2g manifold, with the 14b and got 7psi to 7500rpm with no a one fluctuation in boost pressure. (Tried it out the first time and realized the gate had a 7lb spring, not the 15psi one I had ordered.)

Internal wastegates are means as a low-cost option to regulate boost, on a forced-induction friendly engine. They often do not make less then 10psi due to cost/assembly, and the fact that a turbo engine from the factory can at least handle 10psi with their forged pistons, and the use of a knock sensor.

When you see "Turbo conversion" kits, you usually see an External wastegate right? Thats because the wastegate has a much larger valve area then an internal unit, and thus able to Bypass more "waste gas", producing the low boost level, nessisary for a non-turbo engine.

This is crucial to making a rock solid boost level at all operating speeds on a non-turbo engine that does not have forged internals, knock sens, etc.

So you see, any turbo can benefit from the use of an External wastegate, its all about what the application is for.

Boost is more regularly controlled with the use of an external unit, no matter what the application!

 

[DSMJim]

yeah, that post isn't right. the wastegate is what controlly the bypass of exhaust gasses around the exhaust turbine. the faster the turbine spins (the more gasses that go through it) the more boost is produced. running lower boost will cause the wastegate to open more because more exhaust gas will need to bypass the turbine to slow it down. so in other words, without modifing the wastegate, i won't even be able to run below whatever psi the wastegate is set at without modifing it.

Are there any good turbos that are small that require use of an external wastegate?

Any turbo can use an external gate 14B included. Just take off the wastegate actuator and weld the flapper door shut, then install your external on the o2 housing (which would be easiest for a stock maniflld setup) and your ready to go.

You could then get a external wastegate with a really low spring like 4psi and adjust it from there with a boost controller.

 

[SpoOLxExO]

Uhhh Jim, when you weld the internal shut, you can't use the o2 Wastegate method. You just roadblocked that option!

To clarify, the two most common methods of installing an external wastegate are:

#1- Wastegate off the Exhaust manifold runner. This is the method that includes welding the stock internal flapper closed.

#2-Wastegate off a custom o2 housing that places the external unit, just after the stock valve off the O2 housing. The flapper can either be left alone (Free) or removed entirely, to allow more wastegas to be bypassed.

 

[91TalonTSiCT]

You will have less boost if your ignition timing is advanced too far. The inability to retard the timing enough will result in the BCS limiting the boost. I just fixed mine today and it went up from 6-7psi to 10psi where it should be.

 

[fr33b1rth]

Any turbo can use an external gate 14B included. Just take off the wastegate actuator and weld the flapper door shut, then install your external on the o2 housing (which would be easiest for a stock maniflld setup) and your ready to go.

You could then get a external wastegate with a really low spring like 4psi and adjust it from there with a boost controller.

the lowest springrate i can find is 5.7 and 5 PSI will prolly be the limit, so i don't want to chance 6... you know of any wategates that will run less?

 

[DSMJim]

Uhhh Jim, when you weld the internal shut, you can't use the o2 Wastegate method. You just roadblocked that option!

To clarify, the two most common methods of installing an external wastegate are:

#1- Wastegate off the Exhaust manifold runner. This is the method that includes welding the stock internal flapper closed.

#2-Wastegate off a custom o2 housing that places the external unit, just after the stock valve off the O2 housing. The flapper can either be left alone (Free) or removed entirely, to allow more wastegas to be bypassed.

Pfft yeah, hahah obviously. You would only weld it if you were going off the maniflld not o2 housing.

the lowest springrate i can find is 5.7 and 5 PSI will prolly be the limit, so i don't want to chance 6... you know of any wategates that will run less?

The lowest spring will be the Turbonetics delta gate i'm sure. See if they have a 4psi spring. Otherwise your best bet would be to get a Tial wastegate with a 6psi spring then start cutting half coils off it and test it in a friends car until you got down to 3-4psi.

I acctually had to do that once and I tested it in my car since I can run from 0-22psi safely I just took a 10psi spring and cut the top coil off it and got to a 6 psi spring. It was for a buddys car who was in a pinch so I didn't really care. It worked and stayed working for a really long time that way so, ghetto yes, but it will work as a last resort.