m2cupcar

iTrader: (5)

I use an EGT and it has dependably relfected my changes in fuel and ignition settings while tuning. It's installed in the collector, about 1" from the turbine housing mounting flange and the tip is centered in the collector.

If you used a turbine housing with a standardized exit setup (like a Vband) you could easily swap housings out. You could even swap out housings to better match the application. Say for track events "drop in" your bigger turbine housings. Since you're starting from the ground up, you could "engineer" it for simplified swaps. - rob

Markp

As M2 states, a Type-K thermocouple (aka EGT probe) is the most commonly used and accepted method for measuring EGT's, it's usual mounted right at the turbine inlet (hence the name T.I.T. *Turbine Inlet Temp*.)

Mark

hrk

iTrader: (6)

Manifold mocked up:
http://russmarshall.com/v/cars/cmc7/...10900.JPG.html

Turbo kinked a bit to get straighter shot for exhaust.

hrk

:edited hotlink away

m2cupcar

iTrader: (5)

Nice. This is quite exciting. It looks as though you're building the track car that will whoop up on the big dollar machinery... your intent? You need a front hoop so you can cut loose in SPU - no? When do you think you'll be on track? I've got a got some Miatas lined up for Rd. Atl track events in 07- hope you're there... would hate to miss the debut.

Braineack

iTrader: (62)

TurboTim

iTrader: (9)

not to be ---- but isn't the GT28R now GT2560R? The GT25R is now GT2554R?

Anyways from the pics it looks to be the GT28R. It should spool fast on your 1.8.

hrk

iTrader: (6)

Thanks Tim for pointing that typo out. GT28R is what the turbo should be, but I'll check the part number and measure the wheels to be sure.
"For those familiar with our product range, this means that the unit formerly known as "the GT28R" (part number 466541-1) is now in the GT25R family. More specifically, it is now a GT2560R model."

One concern is that this turbine housing is marked .48, where can I get bigger ones in case it is too small for track use?

Thanks Rob for the idea of swappable turbine housings. I have kept that in mind and the placement of the turbo should allow it.

The exhaust will have 4" long cone from 2" to 3" and then few 45 degree bends and a muffler of some kind.
The wastegate needs to be figured. Is there a problem bolting the Tial upside down very close to the manifold? Heat?

Yes, this car is trying to keep up with fast cars there. So far it has been fine, only straights give troubles. 116 mph doesn't cut it in Road Atlanta.
It has full cage and would be good for SPU as it is and SPO after turbo. No funds to race in both SCCA and NASA. The latter has a class for these (and turboed Miatas too if one would like to do time trials or wheel to wheel racing)
and the schedule can be found:
http://www.nasa-southeast.com/schedule.jsp

hrk
hrk

Splitime

iTrader: (24)

Orientation of the WG isn't an issue. But consider its location with regards to exhaust flow. On a log... its not really that much to think about, but keeping it more central will allow it to regulate the gases better.

ie: don't put it on one end of the header

hrk

iTrader: (6)

Ok, Time to revive old posts.
Story continues and so will questions.
Where are you guys picking up boost signal for electric boost controller?
I saw some referring to pick it up from manifold, but I would be worried of stessing the turbo and intercooler pipes if I am modulating gas in corner with throttle and the poor turbo is pudhing against partly closed throttle with all it can give.
Should I put it right after turbo?

hrk

cjernigan

iTrader: (13)

I have a fitting on my compressor housing with line that T's off to the wastegate then to the EBC solenoid. Then the other side of the solenoid connects to my wastegate. That's for a tial external gate, not sure what you're using.

Edit: Just went and looked. I would drill and tap the compressor housing or my IC piping that way you don't have a long vac line coming from the intake mani all the way to the other side of the car.

mschlang

If you are modulating mid-corner, there will not be enough mass flow to generate massive boost pushing against a closed throttle. The throttle is the ultimate boost controller, not RPM.

Motorworx

hrk, on engines I do for circuit with external w/g, the actuating line (closest to the valve) goes to a boost/vacuum source. When the throttle is closed, it pulls the BOV (right next to the throttle) open, and the w/g closed. Keeps the air-stream moving in the correct direction, and keeps what exhaust pressure there is on the turbine to keep the rpm's up. If you have misfire capability, throttle/power response will be almost identical to an N/A engine. If you like your turbine, and don't use the anti-lag, it still works very well. The upper part of the diaphragm (farthest from the valve) goes to the boost controler on a boost-only source. If you run that off of a vacuum source, it will try to pull the valve open during decel.

VRTSid

not really a comment but more of a question, bravo sir. thats sexxy.

for motorworx: could you explain boost/vacuum source to me? and also when you say "upper part of the diaphragm" what component are you talking about the wastegate or bov?

Im a little confused... when you say *source are you talking about a fitting on the IC pipe/manifold/ect that feeds a boost signal? or are you talking about some sort of vac canister that I have no idea about?

I know its not my thread but I like to know what you guys are talking about

Motorworx

boost/vacuum source means after the throttle and before the valves. Someplace that you can reference vacuum as well as boost. I am only talking about the wastegate (w/g). The source must react instantly to changes in the intake manifold; under boost, it wants to push the w/g valve open, under vacuum it wants to pull it shut. External waste gates have an upper and lower port. When hooked up correctly, they are in what's called "stand-off", where the boost trying to push the valve open "fights" the boost on top (lower because the controller limits it) keeping it closed. When hooked up like this, boost response is much faster.

hrk

iTrader: (6)

Thank you for your comments!

mschlang: I was thinking along same line about the boost, but was worried about spikes, or gradually releasing throttle.

I do have Tial with two ports as my external wastegate, Tullos electrical boost control and GM boost control solenoid.
The way I understand cjernigan has his set up is (please correct if I am wrong):
- if boost control solenoid is wide open both sides of wastegate sees the same pressure and stays closed.
- if boost control solenoid is closed the boost affects only to lower side of wastegate, allowing it to open.

The way Motorworx describes the lower side can have boost or vacuum, and the upper side can only have boost if boost control solenoid is open, if it is closed then the pressure from below (manifold) opens the wategate.

Now that brings me to another question:
Assume boost controller closes the valve at 10 psi.
Car is gradually bringing the boost from 9 to 10 psi. At 9 psi both sides of wastegate actuator sees 9 psi and nothing moves. Boost builds. At 10 psi boost solenoid closes. Where does the pressure on top of actuator go to allow the bottom pressure move valve? Is it vented to atmosphere with GM solenoid somehow? If not the pressure differential between the top and bottom part of the WG actuator remains quite small and WG doesn't open.

Hope this makes sense.

hrk

cjernigan

iTrader: (13)

HRK- Sounds like we have the same setup as I too have the Tullos and GM solenoid.

VRTSid

awesome thanks, I didnt know some wastegates have 2 ports, thats really cool to know.

I was pretty sure the about the boost/vacc source. but, better to ask a dumb question than make a stupid mistake.

hrk

iTrader: (6)

The answer to my own question is: GM boost solenoid vents to atmosphere, so the pressure is released and wastegate can open.

And to another question:
The first road race in Saturday and I'd like to start carefully and use as little boost as possible. Basically I consider this as a test day for next months outing in Road Atlanta.
However I have 7 psi spring on wastegate.
Is there simple trick to lower that rate?
I have stock 1.8 (230cc/min ?) injectors and RX7 460 cc/min ones.
As you might think, there is very little time for testing between today and Saturday, and I'd like to keep variables minimum this time. How much boost can stock injectors handle and can I get wastegate opening that low?

Thanks
hrk

cjernigan

iTrader: (13)

Your EBC should let you run 3 psi using the Tial and GM solenoid. If not 3 then i know you can run 5 because i have on my similar system and the 1.8 injectors work just fine for that much boost. That's been my experience atleast.

hrk

iTrader: (6)

Well, how does the EBC make 3 psi pressure if the spring is open fully at 7 psi?
Is the Tial open partly at 3 psi?

hrk