Originally Posted by 333pg333

How do the anti-surge housings work? Someone mentioned that they have holes on the housing itself. How are these activated? Are they prone to failure?

Originally Posted by hosrom_951

Guys,
If there is any doubt regarding Garret's Dual BB turbochargers, nize is running one and he will report if anything happens (which i don't expect), and since he already shared a ton of info on the turbo and car set-up, as well as datalogs, he is surely to share info on this.

So, put you're differences aside, time will tell.

Originally Posted by nize

well said. i just wish others would be as open and share information and technical specs. that is, if they know what they're talking about.

Originally Posted by Porschefile

You're an idiot. Go back to your trailer park. As for my experience? Mainly Japanese stuff, and I'm sure that doesn't surprise anyone. The last couple motors I put together were Nissan Sr20's for a friend's couple of drift cars (drifting is lame ). As for what components, SSAC stainless header (never had any problems even though it's mass produced Chinese stuff), Carillo rods, CP Pistons (stock ~8.5:1 CR), stock valves, stock ports, crower springs/retainers, Tomei solid lifters, HKS 272 deg cams(advertised, can't remember specs @ 50deg), ARP headbolts, HKS MLS headgasket (stock thickness), Trust large capacity oil sump (adds 1 qt), Koyo 2 core aluminum radiator, Gt2871r .64 t25 flanged and internally gated (not my choice, not a fan of the t25 housings on this type of setup), Apexi Power FC plug n play standalone. That's all I can remember off the top of my head. Like I mentioned, my friend bought the turbos for these last 2 cars and wanted to use them. Personally I would have gone with a .82 T3 hotside considering the high rpm the motor was capable of (9k rpm is where we set the limiter). Anyways, I believe it was acheiving full boost at ~4.2k rpm but was a little laggier than it should have been as it had a crappy MBC that wasn't working too well. At 18psi on 93oct the car made ~340-345whp. At 22psi with C16 it made ~390whp. That t25 hotside really choked the motor out considering the high rpm and cams (272's) to take advantage of it. In all honesty, there really wasn't any point revving the car out more than ~7.5-7.8k considering how restricted the hotside was. Anyways, I've done several setups like this in the past. A good friend of mine is a drifter and I've helped him build his cars. Unfortunately he gets a bit too buy happy and buys some mismatched stuff that I end up having to work with but, oh well. I've only ever really done the mechanical side of things with his cars as he usually goes to a pro shop to get things tuned. Anyways, he beats the ever living sh*t out of his cars when drifting. So far we haven't had any problems related to his turbos. I've only ever had good experiences with the GT series. Lately I've convinced him to go to some road track events, which he seems to enjoy quite a bit (who wouldn't!)

Originally Posted by A.Wayne

Regarding the turbos shown above , with the anti-surge ports , why would anyone want a turbo like that .... the inlet design will have flow problems
Size the turbo for your application and you will not need a design like that..

A Poor inlet design to the turbo and can cost you as much as 10% in peak power if not done right.....

Originally Posted by nize

what boost level will you be running? what's the point of getting more lag if you can hold 21+psi to redline with this turbo?

Originally Posted by Dempsey Shelby

There are two aspects to consider when dealing with boost response: engine factors and driver factors. As far as engine factors go, there are many things which affect turbo lag... although most are directly related to the design of the turbo itself. Turbos can be designed to minimize lag but this usually comes at the expense of top-end flow. In other words, you can barter for instant boost response by giving up gobs of horsepower in the upper third of your RPM range. (Behold the catch-22 in designing one turbo for all uses.)

Originally Posted by howstuffworks.com

A small turbocharger will provide boost more quickly and at lower engine speeds, but may not be able to provide much boost at higher engine speeds when a really large volume of air is going into the engine.

Originally Posted by turbosbygarrett

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.

Originally Posted by turbosbygarrett

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 where the engine will be operating at high engine speeds most of the time.

Originally Posted by A.Wayne

Sr20 to 9K , Hmmm very interesting would like to have seen the valvetrain system used ...

Originally Posted by Porschefile

Noting magical about it. You'd be surprised at the number of people that do it, and how relatively easy it is (equally easy to screw up too ). Stronger rod bolts, stiffer valve springs and lighter retainers, a cam to take advantage of it, metal headgasket, solid lifters and that's about it. The stock water and oil pumps are both equipped to reliably handle the rpm. Above 9k though, there are other upgrades that need to be done such as a different oil pump among other things. These motors have a typical rocker arm design whereas ours are cam on bucket. There is also a factory Nissan variable timing and lift n/a version of these motors (SR16ve - 1.6L, and SR20VE - 2.0L). The sweet thing about them is the stock oil pumps are capable of withstanding 9.5k rpm and in stock form certain versions of these "VE" motors have 280 degree cams on the high lobe. Almost all of that stuff is interchangeable with the non variable timing & lift motors. Factory upgrades are always cool.

Originally Posted by nize

first post updated with more data. the bigger dbb actually spools almost twice as fast as the stock turbo.