3" single from the turbine all the way back.

 

Nice well that rules out the exhaust as the issue. GL

 

Well, I have been back and forth with a Tial rep. He is convinced that the turbo 6162E
(.81a/r) is runing out of air. I don't understand how that can be considering the hp rating of the turbo.

 

thanks for sharing the honest results. surprising that the 8.7psi spring didnt hold.

The dyno's i've seen just on springs have a pretty flat boost curve. hopefully you can get everything installed and redyno'd to figure out what the problem is.

The STS kits use a smaller turbo and dont have that problem. IS this the kit with the wastegate that got reclocked?

 

hmm.. Isnt that turbo the same as a gt35r?

 

With the 3.3 FD 4th gear is the closest to 1:1. Running in 5th would almost be like dyno pulls in 6th on a stock rear drive.

Nice results Sasha, keep working out the kinks and it will be right where you expected. Is the dyno being used a DJ or DJ comparable? Just trying to get an accurate understanding of the #s.

 

The wastegate is in the same location as I have had it on my old setup last year. It is just before the T3 flange.

That is what I thought.

Thanks, I think the numbers are good considering the drop in boost. The car drives great, nothing ratling anywhere, great clearance (it's winter ruts are massive here) and it sounds just awesome. I am very happy with it. Just have to prove that this kit is capable of making great power.

I am not sure what you mean by DJ, or DJ comparable.

 

Is the dyno a Dyno Jet model, or does it produce numbers similar to a Dyno Jet dyno? Are the numbers more comparable with a Dyno Dynamics dyno (10-13% lower than DJ readings)? Basically is it load driven is the question.

 

Great job.... I am impressed!!

 

It is an enertia dyno, not load driven. The owner tels me that since the dyno is brand new it is reading a bit lower than what he has seen on other DJ dynos in town. So I guess a Dyno Jet model..


On a side note, I will be hooking up the boost controller and probably go back next week.

 

It says "Dynojet" on the dyno sheet. The 1.04 correction seems a bit high for 73 degree temp. My dynojet run at 71 deg F had an SAE correction of 0.98. Probably the humidity and altitude adjustments... SAE is the best for comparison purposes, BUT GTM uses STD, which is always a bit higher, so in comparing that TN kit, the results are skewed in favor of the TN (STD vs SAE correction).

For some reason that wastegate is seeing higher pressure than it should - weird. Hope you can get it sorted.

 

that graph was produced on a dynojet dyno, SAE correction adding 4% overall, and a smoothing factor of 5 (max setting)

it says it was 73 degrees in the dyno room... i assume the garage doors were closed???

 

Correct.

 

i think your numbers are already a great success for the boost level. i think it will make 425ish at 8psi, possibly a tad more.

could you audibly hear that the wastegate was still open just before redline? do you have a video of the runs?

 

Thanks Charles. I could not really hear anything to be honest, dyno and exhaust noise were the only things I heard.

 

I ask, because I am wondering if this is a problem with the wastegate opening prematurely, or an issue with the turbo not being provided with enough exhaust gas/energy (for its size) to sustain the target boost at higher RPMs, or the opposite, it being too restrictive.

The first thing I would have tried would have been removing the vacuum line to the wastegate and seeing if I could get more boost towards redline like that... but of course, regulating the boost with throttle is not a very safe idea if you do not have a boost-fuel cut, as you could quickly destroy the engine. it would simply be a momentary diagnostics to rule out a couple things.

I would contact STS and ask them if the Tial rated spring pressures are considered accurate for the rear mount setup or not, only to use as a very exaggerated comparison. because I would wonder if there is a related side effect. I would have to imagine that the compressor outlet pressure versus turbine inlet pressure ratio may change the further the turbo is placed from the exhaust ports, as the heat/pressure in the exhaust stream should be less the further down you go, even at the same intake pressures.

 

I think it is the wastegate opening do to back pressure. If my exhaust pressure is even 2psi pre turbo, it would be like having a 6psi spring in the gate. It doesn't make sense though, I don't think the other kits come with a boost controller.

But then again, isn't this how it goes. You need back pressure to make the turbo spool, and large exhaust after the turbo. This allows the exahust gas to pass through the turbine with velocity making it spin.

There is also a small posiblity of a boost leak somwhere. I will be looking at this as well.





Contacting STS would not get me anywhere. My exhaust length to the turbo is very much comparable to the top mount turbo systems. All of my ehxaust (pre turbo) is 2.5" diameter, so it can not possibly be restrictive.

 

Just to clear up a few things. Final drive ratio has no relevance on what gear in the transmission is closest to 1:1, and in the Z's CD0XX series trannys that happens to be 5th. With that being said I still do most of my dyno tuning in 4th to alleviate stress on the stock motor and just finalize my timing in 5th.


Now your boost issue I've been there several times in my life!
There are only a few logical things it can be, lets go threw them.
1. Like you have mentioned, running out of turbo. I dont know anything really about that turbo but from the name I'm assuming 61mm inducer on compressor side? If thats the case that sides not your problem being that it should flow around 60-65 lbs of air.... Do you have specs on the exhaust side? Is it a 62mm exducer? Reason I ask is we have seen several cars were the compressor cfm is irrelevant because you simply cant flow that amount of expanded air through the exhaust wheel. One car we have is stuck at 540whp with a 62mm inducer on the compressor side because the exhaust wheel is too small(dont remember the size) but that compressor should flow over 600whp...

2. Next would be a restriction anywhere from the point the expanded gasses leave the turbo to where they leave the exhaust tip. A restriction there will limit shaft speed big time, drop the exhaust on the dyno and try again. I know you mentioned that it was 3" but really who knows whats going on in that muffler

3. Any exhaust leak prior to the turbo will also have an effect on shaft speed due to limiting pressure before the wheel. I've noticed this most on turbos that are fairly large for the displacement thats driving them...

4. If your waste gate reference is at the turbo(beginning of system) and and you boost gauge reference is at the end of the system(intake manifold or upper charge pipe ect..) then you simply might just be experiencing pressure drop across the system. To resolve that(well not resolve it, more like disregard it..) simply move your waste gate reverence down the line, cold pipe, prior to TB.

Realistically if everything else is up to snuff what else is there lol.

Hope this helps in any way good luck!

 

You dont subtract exhaust pressure from wastegate spring to calculate end result, typically, it should just run the spring pressure.

tons of exhaust backpressure is normal especially on the smaller turbo systems. A typical side mount turbo kit will hold the same boost from the moment it makes full boost all the way to redline... when operated within their range anyway. Greddy kits actually have a little spike over spring pressure when they first spool, probably because of the non-ideal wastegate dump reentry position and angle. Typically, you shouldnt need a boost controller to hold spring pressure to redline, especially in low/medium max boost circumstances.

I know that your design is much more optimum than the STS kits, I wouldnt compare it even by a longshot. The reason I mentioned contacting them, is because its a very exaggerated example of putting turbos at distance from the engine. If the distance they run it requires running heavier springs to get boost levels lower then the springs tial ratings, then that tells you that you an extrapolate that and figure that into your setup.

I never played with the turbonetics or powerlab kits, so I am not sure if they experience an effect or not. But I can figure that percentage wise, yours, while close in comparison to the STS kit, is still worlds further than a typical side mount... where a side mount is only inches from the exhaust port, yours could be 10+ multiples of that.

Which i am not at ALL saying is a problem... All I am simply getting at, is that I have just a theory that perhaps as you get further from the exhaust port, you might have to step up the wastegate spring a notch... and i have no idea if your kit would begin to experience that or not.

I am just taking guesses to help figure out where your boost is.

Hopefully it is just a pressure leak, or pressure drop across the system only requiring you to relocate your wastegate pressure reference. I was just trying to think of things further down the road if it wasnt solved easily.

 

A few more comments based on Phunks response.

Exhaust back pressure after the turbo does have a fair affect on end psi. Lots of cars I see on the dyno make more boost after dropping the exhaust Ask Tial, they say spring pressure is only an estimate on boost produced. My car on a tial 3psi spring make a flat 5psi and on big yellow 9psi it makes 10-10.5 flat. And with my turbo in the front bumper I would say me and Sacha have similar pre-turbo length? That would rule out larger springs being necessary.

But then again I could be wrong and he may have alot more length than me