I haven't researched it enough.. what would be involved in switching to external wastegates on the APS kit?

I like that GReddy went with external wastegates, but I much prefer the Garrett turbos that APS is using. I just haven't had great experiences with internal wastegates and proper boost control.

Thoughts?

 

a whole different kit would be involved. manifolds, downpipes, extensive work on the turbo actuator removal and on top of all that still no extra ponies . IF you are certain you want external wastegates buy greddy or make something custom. that your best bet. but if aps's kit does not boost spike and you like it so much buy it. Its one less spot you will have to worry for an exhaust leak.

 

Hopefully the Unichip will have the ability to control the solenoids with a little more accuracy.

 

Weak.

I suspected so.

I love the attention to detail in the APS kit. Worlds better than the GReddy kit. Not to mention the FMIC. The GReddy FMIC is oversized, blocks the radiator too much, and removes the structural supports in the bumper. Completely unacceptable to me.

Internal wastegates dissapoint as well, though, as I'd like to boost in the 18+ PSI range after I build the block. I'm sure the internal wastegates work great for 0-10 PSI, but I have my doubts about higher boost levels.

I might have to go for a fully custom setup.

 

You would need a new exhaust housing with the proper A/R. You may be able to find one that has an external wastegate mount built in but it's not likely. If that option is not available then the manifolds need to be tapped and a wastegate tube and flange would need to be welded on. You can have the wastegate dump back into the exhaust, but its gonna be alot easier to have them dump to atmosphere. The Greddy Type-R is really skinny and should work.

Who like the awesome photoshop work?

 

I was hoping this would be possible. Maybe we could purchase the turbo exhaust housing for external wastegate from Garrett, tap the manifold and exhaust piping, and plumb in the wastegate.

As far as I'm concerned, I would require it to dump back into the exhaust. Similarly, I want a recirculating blow off valve, because I want as stealth a setup as possible. No noise, no bling, just power.

My requirements seem to be different than most people.. I'm looking for, in this order:
1. Quality/fitment/attention to detail
2. Stealth (quiet)
3. Power (500+ RWHP potential)

Unlike most kits available or in production, APS fits the bill in 99% of these respects, I just really want to make sure I avoid fundamental problems like boost spikes, etc. If these issues are addressed up front, it can relieve potential headaches later. Unfortunately, GReddy skimped on quality and attention to detail, and Power Enterprise chose small turbos to keep lag down.

By the way, thanks for the picture and explaination -- I had a theory of wastegate operation but the picture helps confirm everything.

 

Not a problem. The internal wastegates should be ok. It will come down to the boost controller. You may need to use an electronic boost controller (HKS EVC always works well for us) and possibly get a new actuator (you should be able to find one with a higer spring rate, I think HKS offers some for Garrett BB).

There are some distinct advantages to the external wastegate as you mentioned. No leak, but they also react faster and allow a better flow path around the turbine.

Turbonetics should be able to set you up with a new exhaust housing. You will need to take the current housing off and measure the exducer and inducer diameters (small circle and big circle) and tell them the outlet diameter. You may be able to send the turbo to them to have them take care of it all.

Edit: The housing should not be more then $200-300 each.

 

I run 25 psi on a Mitsu 25g TD07 turbo w/ an internal wastegate, it works great.

 

You know what. Just remembered. You have to make a new downpipe. Not a big deal, just get the outlet flange and have a 2.5" tube welded to it. (Just an FYI) We sell the Nissan 3 bolt flange for the other side.

 

It sounds to me like the internal wastegates will work for over 20 PSI. Why would someone dump them for externals? And what are the pros of internals?

 

If you have the correct turbo control actuators (wastegate actuators) and pressure solenoid then controlling/mapping boost pressure via the computer is just so easy.

I really would not bother going to all of the trouble and extra expense of remote style waste gates as this realy complicates the TT install and for what real advantage................wastegates only control turbo pressure and the integral wastegate style does control turbo pressure very well if sized correctly.

Peter

APS

 

if done right internal wastegates are just fine... especially if you dont care to vent external then there is no need for them. internal gate setups are cleaner and less clutter if you ask me.

my friends 300zx has no problem with a pair of garret twins on it... boost anywhere from 20psi - 29psi never had a problem with boost spike or proper boost control... matter of fact his car had probably the most rock solid consistent boost controlling i seen with these internal gates and blitz sbc-id controller.

either way greddy kits have boost spike issues even right out of the box. I run my car at 7.5 psi, sometimes 8psi. If I nail it full throttle at the right point, it can have a very short spike of anywhere from 8.5-10.5 psi.

-Charles