andrew_ptuning

"The A/R parameter has different effects on the compressor and turbine performance, as outlined below.

Compressor A/R - Compressor performance is comparatively insensitive to changes in A/R. Larger A/R housings are sometimes used to optimize performance of low boost applications, and smaller A/R are used for high boost applications. However, as this influence of A/R on compressor performance is minor, there are not A/R options available for compressor housings.

Turbine A/R - Turbine performance is greatly affected by changing the A/R of the housing, as it is used to adjust the flow capacity of the turbine. Using a smaller A/R will increase the exhaust gas velocity into the turbine wheel. This provides increased turbine power at lower engine speeds, resulting in a quicker boost rise. However, a small A/R also causes the flow to enter the wheel more tangentially, which reduces the ultimate flow capacity of the turbine wheel. This will tend to increase exhaust backpressure and hence reduce the engine's ability to "breathe" effectively at high RPM, adversely affecting peak engine power.

Conversely, using a larger A/R will lower exhaust gas velocity, and delay boost rise. The flow in a larger A/R housing enters the wheel in a more radial fashion, increasing the wheel's effective flow capacity, resulting in lower backpressure and better power at higher engine speeds.

When deciding between A/R options, be realistic with the intended vehicle use and use the A/R to bias the performance toward the desired powerband characteristic.

Here's a simplistic look at comparing turbine housing geometry with different applications. By comparing different turbine housing A/R, it is often possible to determine the intended use of the system.

Imagine two 3.5L engines both using GT30R turbochargers. The only difference between the two engines is a different turbine housing A/R; otherwise the two engines are identical:
1. Engine #1 has turbine housing with an A/R of 0.63
2. Engine #2 has a turbine housing with an A/R of 1.06.

What can we infer about the intended use and the turbocharger matching for each engine?

Engine#1: This engine is using a smaller A/R turbine housing (0.63) thus biased more towards low-end torque and optimal boost response. Many would describe this as being more "fun" to drive on the street, as normal daily driving habits tend to favor transient response. However, at higher engine speeds, this smaller A/R housing will result in high backpressure, which can result in a loss of top end power. This type of engine performance is desirable for street applications where the low speed boost response and transient conditions are more important than top end power.

Engine #2: This engine is using a larger A/R turbine housing (1.06) and is biased towards peak horsepower, while sacrificing transient response and torque at very low engine speeds. The larger A/R turbine housing will continue to minimize backpressure at high rpm, to the benefit of engine peak power. On the other hand, this will also raise the engine speed at which the turbo can provide boost, increasing time to boost. The performance of Engine #2 is more desirable for racing applications than Engine #1 since Engine #2 will be operating at high engine speeds most of the time."


Ripped right off the pages of Garretts website. Any questions you have on A/R options can be found in those paragraphs!!!

The main reason we Chose the .82 A/R for our exhaust housing, Was due to the fact that it was the middle of the line in turbo housing selections. ".63A/R .82A/R 1.06A/R." It allows for quick spool, and a very capable top end.

We also found it to have very good street manors for city driving, with that size A/R housing.

Thank Drew

rhythmnsmoke

Indeed it does. Maintaining normal driving ability without eating up the gas because you don't have to go into boost that much. Smaller A/R you will be boosting just going up a small hill. If I'm just driving normal, I only give her enough gas to hear the ball bearings spin, and then it's onto the next gear.

Coming from a 16G turbo then a 20G turbo...now rocking the 3076R on the PTuning setup. My older much smaller turbo's were ideal for street use. They were more "violent" per say and will slam you in the seat at the touch of the throttle. That's the "fun" to drive factor Garrett talks about in their article. But try putting that on a track or autoX. You will be fighting a lot of torque steer and traction issues because Peak Torque is so far down low that you can't get on the gas that much until you have hit high enough RPMs, bypassing Peak Torque.

Another article I read was talking about this as well. Forget the famous racer who made the statement, but he said something to the effect of...."If you want to maintain the most traction around the track, then stay above Peak Torque". Of course you will only find where that is by looking at your Dyno sheet.

With my new found power from the 3076R, this baby is so much smoother in it's climb. I think I've heard the saying before that...."A somewhat boring car, is a fast one". It's a gradual build and when you are moving, it's a continuous acceleration. It's like being sucked through a Vortex piece by piece rather than getting slammed in the back by a small car through a hole (small turbo boost hitting). The .82 A/R is easier to control on the track and maintain your traction. My new setup (PTuning Spec RS) isn't as violent as my old setup...yet it's 3x faster even at the same boost pressures.

We will be putting 2 PTuning setups and one Custom Setup on the track this weekend. Time to lay down some rubber.

BeloZero

I see. thanks for the info. i was under the impression that the .82 a/r was the biggest housing for that turbo. oops!

mmmpshh

iTrader: (5)

nice write up on hot sides. Im actually trynna figure out if I wanna do a .63 or a .82. Im on a .63 right now and I do like it... do you have dynos or any info for a .82 on a tc1? I'd like to see what the power curve looks like...

MightyP

iTrader: (1)

I would love to do this but don't have a shop in the area that'll install it and after seeing all the issues Zeroeyequeue had installing the competitor's turbo, I'm not sure how many shops I'd trust to install a turbo

rhythmnsmoke

You can find "Slikk"'s thread, he's running a .82 A/R 3076R @ 8.8lbs of boost, and you can also see my thread @ 11lbs of boost. We have two different torque curves (mine is a 2006 tC and his is a 200.



Do you know how to follow directions easily? Cause speaking from experience with PTuning's kit, it comes with a installation manual that's very detailed and specific. If you can follow directions, and turn a wrench (mechanically inclined) you can install your own kit.

I installed my own kit, drove 11hrs up to PTuning from TN, laid down 326whp/320wtq on their dyno, and then drove 11hrs back home with ZERO issues. The only issue I had is that no one bothered to give me a test on the way home...

Scratch

iTrader: (3)

...and if you need a place to crash when you come up to get your "BOOST=WIN" I'm just down the way from PTuning, going there at lunch actually

ZeroEyeQueue

I'd just browse for tuning shops in your local area. Any aftermarket tuning shop should be able to install without problem. I installed the actual kit myself with the help of a friend who is a mechanic. The problem with my stuff was that the base map wasn't set up for the turbo I ordered and I didn't have all of the parts. It runs fine now after a tune. PTuning's stuff is super legit from everything I've read about them.

Although, if you were to get the Descendant kit, I'd opt for the turbo upgrade to the ball bearing Precision turbo. I'm already having issues with my Turbonetics. I'll be upgrading to the Garrett GTX 3076R with hopefully a .81 AR, but most likely a .6, if the shop can get a hold of one for a good price. Most of the stuff I've looked up about Turbonetics ends up with a lot of issues. Go with a Precision or Garrett. Precision for numbers and Garrett for reliability.

PTUNING

iTrader: (1)

In addition to what everyone has stated, we will not release a kit if there is a problem. We have enough experiences from building the Scion tC1 Spec-SS, Spec-RS, and soon a custom Spec-TA kit (for a customer) and S2000 production kits that when the tC2 turbo kit is release and shipped, it will be a clean bolt-on just like all the production turbo kits we have released.

You probably already know about our tC1 turbo kits from ScionLife, but here is what customers have said about our recently released S2000 kit on the S2k forums, under the thread title "Best turbo for daily driver"


"1- The Ptuning kit is pretty new and hasn't been around long enough or installed on enough cars to have had problems yet. Thus nobody has reported any failures and it has a great rep. By contrast, most of the other kits have been around long enough for people to report issues like manifolds cracking, stuff breaking or falling off...

2- It's a very well designed, well thought out, comprehensive, complete kit using high quality components that should last. Thus we like it and perceive it to be reliable.

One reason it's so popular, besides the quality of the kit, is the torque curve. Traditional log manifolds spool fast but don't make big power at high rpm, and traditional equal length tubular manifolds spool a bit slower but make big high end power. The Ptuning kit design gives you fast spool, strong low end & midrange, and still makes lotsa power up high. It's a great solution because it's so efficient and doesn't have the downsides of many other designs."


Here another post from the same forum in responding to the above post:

"and to add to this the turbo sits really low and coupled with the heat shield this reduces the amount of heat in the bay. I was skeptical about the heat shield but it is quality stuff. I have almost 2000 miles on the kit with no problems that were not due to intaller error. "


and another post:

"Also adding to what these guys have said, the Ptuning kit uses all vband connections, so you won't have to deal with studs/nuts vibrating loose or snapping. Due to the low placement of the turbo, the downpipe is virtually a straight pipe (almost looks like a long test pipe) which also aids in the fast spool of the turbo."


Hope this help with your decision

scionchicop

Does kit come w/pre-tapped oil pan like the descendant kit does? Is it necessary?

OBrien_PTuning

Got a third!

Come on guys, we only need 2 more people in order to make this a reality!

scionchicop

Come on!!! 2 more people. Hurry up and jump on this kit.

BeloZero

YEAH!!! nice to see a third.

scionchicop

Bump, bump bump it up!

andrew_ptuning

Tuesday bump!!! Looking for two more people.

**FYI This kit was designed with the option to upgrade to the larger frame GT turbos.

Call me at the shop with any questions, thanks Drew.

andrew_ptuning

The 4th spot has been filled!! We are looking for one more person. Call me with any questions

Thanks Drew

scionchicop

Awesome!!! 1 more. Come on...someone get in on this!

Papa_Bear

Is there any possibility this kit would be available in a blow thru setup for the MAF?

OBrien_PTuning

Our TC2 kit is a blow through setup.

scionchicop

Pardon my ignorance, but what is a blow through setup? I tried googling it but no luck.