sweet write-ups rotor. Your system inspires me

 

i finally got my hands on tightening the waistgate spring (after almost a year) to see if the high end will improve, but no.
while the time to full boost increased, as soon as the arrow hits the target boost level, it would start decreasing, and drops into the 5 PSI range.

I remember when i just build it, that drop down level was 7-8 PSI. And that waistgate was not tightened at all I could easily push it open by just applying little pressure to the actuator lever with my finger. Is it possible that my turbo might have some bearing damage that prevents it from reaching proper spool? Sometimes when I shift at high RPM, I notice a puff of blue smoke coming out, at the same time as the BOV lets the pressure off.
Is turbos inability to keep the boost, along with random smoke a sign that it is going? I've never had a busted turbo before, so I have no idea what to look for.

 

That is a possible explanation. A little smoke after a long idle is another sign of that.

 

I never checked that. I should today.

Jeff, how long did your turbo continue to run from the time you first saw the signs of failure, until it totally crapped out and stopped making boost?

 

It actually didn't completely die, it just started to make a ton of noise and smoke all the time.

 

oh.
Mine is making more noise than it used to.
The sound became kind of sharper, and especially when under a lot of boost, it is not constant sssssssss sound like it was before, but has sort of screechy note to it, that may even pulsate with with very short intervals.
I don't know if I am describing it the right way. And also the boost may actually vary from time to time. Like sometimes i watch the gauge while under boost, and it it hitting the target boost, then slides down and as I continue to gain RPM it suddenly will jerk up a little, like from 5 to 7 PSI, and slide again.
All of the experimentation and flooding it with oil earlier, must have contributed to the bearing damage, and now it is beginning to show the signs of aging.
I think it is time for me to get a new turbo soon.

Maybe I should get this one?
http://cgi.ebay.com/ebaymotors/T3-T0...spagenameZWDVW

T3/T04B instead of the T3/T04E that i have now.
What do you think?
the fittings are the same, but will flow more. I wonder though how much it will delay fool boost?

 

I use a T3/T04E.
Over oiling will do weird things.
When my TD06-18G started to fail, it just got a pronounced whine under boost (almost like a penny whistle!) and I could hear it spin down when I shut off the motor with a little "shing shing shing".

 

Unlikely. This patent will get the smackdown because there is so much 'prior art'

 

Patent, shmatent...

I was talking to a local gear-head recently, who he's been building remote turbos himself, for customers for a while. He's a construction worker, and does this as for fun, and to raise a little money for his own car. At least a dozen systems for domestic cars he has build he says. He himself drives a supped up toyota pickup truck with a remote turbo, and it is not STS.

I asked him why remote, and he's like: "Why did you build a remote? Cause it's easy to make, costs less and works just as good..."

The guy doesn't give a rat about the STS's patent. He just doesn't care.

STS wouldn't even bother to go after someone that small. Even if they had all their cards right, they never would have. They hold that patent more for marketing purposes, than anything else.

What I am getting at is this:
if anyone wants to, I'll build this system for them for them. Just let me know.
I'll make all the parts, wrap it up and ship it. All they have to do is just pull off the muffler, put it on, and plug in the hoses :-)

Ok, Intercooler requires some welding, or drilling if there is no welder on hand. Other than that everything is bolt on.

 

What brand of turbo do you have now? Is it just one of the Ebay turbos? That may be a cause to your premature failure. If you want, you could try a name brand Garret or Turbonetics turbocharger- possibly get longer life. The higher initial cost shoudl offset the constant replacements

 

I don't know if the benefits will out weight the cost.
I can pick up a new one on ebay for $145 plus shipping.
http://cgi.ebay.com/ebaymotors/T3-T4...spagenameZWDVW
And the one I have on now (with all the abuse, it was subjected to initially has already run for 15K). And it'll take me 1hour, if not less to swap it.

The same one from Garret (brand new) will cost me at least $1300.

 

Heh, nipples.


Nice work BTW!

You should have seen all the naysayers when I decided to build a custom Supercharger setup for my C5 corvette. "It wont make power" "It will fall apart" "It will be more expensive in the long run" ...ect.

Not only did I build my entire system for less than half a normal kit cost. But it made HUGE power. Too much infact...I got tired of trying to keep a driveline behind it :P

 

Ahh, I didn't know you had over 15,000 miles. For abusive miles, that's decent for a $145 turbo!

Have you taken it off to check your shaft play?

 

Yep, I pulled of the intake sleeve. It has shaft play.
I don't know if it can be considered a large play, but i can shake it with my fingers.
I suppose it is significant given that there is loss of performance.

 

Did you ever see the animation of my turbo shaft wiggle? I don't remember where I put it, you might find it in a search. That was fairly extreme.

 

Yeah I saw it a while back. Now that you mention it... Very impressive
Mine is not that bad, yours was totally gone, but wait another couple of thousand miles...

 

Ha ha,
Thought this would be a cool picture to post.
I was trimming some fuel when in boost, on my way to work, and just took a screen shot. This is 6th gear, accelerating, 80 something MPH

 

Ihave read this thread from beginning to end now, and I have to say I am throughly impressed. I have been waiting for someone in the RX7 community to do this as opposed to a TII swap, but am especially excited to see that it has been done here.


One suggestion though. Have you though about running your intake through over to the drivers side where the exhaust used to exit? Reason I ask is a straight line is always better than any bend, and as you have it now the filter may be pulling slightly warmer air off the turbo. If you were to run even a short pipe over to the drivers side where the dummy exhaust tip is you could pull colder air and have a straighter shot to the turbo. Probably wouldnt result is much of a boost threshold chage, but you may find boost comes on slightly sooner, and having colder air never hurt anything.


Congrats on doing this in either case. Your work has pushed me that much closer to an RX8 purchase. Now if I could only get the fiance to get off this 'lets buy a house' kick


BC

 

I appreciate the comment.
Actually the air filter currently is in the fender well, above the dummy exhaust tip.
It is connected to the turbo through a 3" accordion hose.

 

Good place for it


For the sake of the 'best' airflow to the turbo you might want to consider something that wont induce so much turbulence. Again, its not going to make a lot of difference, but every bit helps right?



BC

 

If it was a race car application you might be right, but it is not.

The car runs fine and I don't think I have issues with starving the turbo of air. though one never knows.

On the other hand, in my case the cost of fabricating aluminum tubing for this would outweigh the benefits.

However I will gladly implement this this for any of my future customers who wishes me to do so

 

Update:
After tinkering for a while with the boost controller, exhaust and intake piping routing, and the waist gate settings, I made the following conclusions: I need a bigger turbo!!! T3/T04E I am running now seems to be maxing out and starting at around 7K RPM dropping boost from 12 PSI down to around 7-8PSI wile making insane noises. With that I had decided to stop waisting money making modifications to the current system, as I had pretty much found it's limits.

Next step:
I will be starting a new thread where a buildup for a new turbo system will take place. Based on everything I have learned from this, I will begin the development of RotoRocks Remote Turbo System Stage 2.

This will have the following components:
T3/T04B Turbocharger (60 A/R Compressor)
External Waistgate
3" post intercooler piping
3" post turbine single tip exhaust with a nice stainless steel muffler and more.

Once the Stage 2 system is complete, the car will yet again be tuned, dynoed and, and the system will be made available for purchase as a kit.

For more information and latest developments please follow the tread titled "RotoRocks Turbo Stage 2" which will be started as soon as the new parts begin to arrive.

Thanks everyone for your support.

 

Any idea what the exhaust temperatures are back there on the remote setup? Garret VNT turbos work really really well at creating boost very quickly, but they're easily destroyed by high exhaust gas temperatures. If the exhaust is cool enough you could use them, but ideally they'd have to be in the diesel ranges - 830 degrees Celcius or 1530 farenheit. A dual turbo setup could work really well.

EDIT: 1530 should be considered an absolute maximum e.g. when the rotary is putting out like 1900 at the manifold - most diesels don't run higher than 1300.

 

Actually the spooling is not my primary concern.
If with the new bigger turbo it will boost 6-7 PSI @ 4K rpm, i'll be happy, but I want it to stay @ 12 by 9000.

 

Rotor...What about fuel and spark...Any plans to update either one?

BTW...I saw your car again (second time) the other day. I think in the Boca area. Bad memory.