There is an absolute wealth of choices out there in the world of turbocharging. Not only are there different brands, specifications, and power outputs, but there are also different characteristics that make for a totally different power delivery.
A wise man once said that “in a mad world only the mad are sane.” This isn’t quite the philosophy that we took when we decided the start this project, but it wouldn’t be too far off. After talking to a few people out there ‘in the know’, we felt that we needed to make an impact. What kind of an impact we were going to make was what we needed to consider first and foremost.
We mentioned last issue that we are building a Nissan 180SX and a big part of that will be the SR20 engine that will be totally refurnished, hence the SR20 being mentioned so prominently in the name. Brawler represents the fact that the engine will make some nasty power, and doesn’t mind a bit of rough stuff too. And this is where the impact of what we are doing comes into play.
Magazines have done the bolt on thing to death many times before. Boring. Wow let’s see, get an high flowing exhaust, bigger intercooler, injectors and fuel pump that can handle the designated power output, some sort of capable ECU, pick a turbo that will pump enough air to generate the power, do the whole blow off valve thing because everyone else does it, turn the wick up, tune it and see how you go, hoping something doesn’t give way. If you are really adventurous you might find about a thousand pages about this on Google if you really search hard enough.
Sure it is the tried and tested method but almost everyone with a turbo car has done this, and it is so easy to do it is almost considered “stock” nowadays. Yes we could do that, rehash the same information that everyone knows and get a couple of stories out of it. But we want to go further and make things a little more interesting. What happens when you crack something in the stock engine? Some brawler that would be, sitting on the side of the road chocking on its own smoke and oil. Turning the wick up on a stock engine is asking for disaster sooner or later. Sure people can get up to 250 rear wheel kilowatts on the stock bottom end of an SR20DET, but for how long?
We wanted to build an engine that wouldn’t be a ‘run of the mill’ engine that would make 220 – 230 rear wheel kilowatts, like plenty of SR20 powered vehicles out there. It just was not enough of a challenge. We wanted to go through the trials and tribulations of rebuilding the SR20 engine into something special, something that will be a tad more reliable than the stock item at 250+ rear wheel kilowatts, and maybe even make a tad more power. And we wanted to take you step by step through the process, from the beginning to end so you can see what is involved, how long it potentially can take, what are good things to considered and who can do the work.
The big power figure is where the ‘madness is sanity’ slogan comes into play. Taking a look at a lot of the SR’s getting around nowadays, they are fitted with some slugs, maybe some conrods, and making some pretty solid numbers. We want to make more. Not the most, just more. Turn those madness numbers into sanity when you compare it to ours. This is where turbo selection is a big factor.
Now with the engine porting underway at Indy’s we felt it would be a good time to finalise the turbo that we will be using in the build. A number of turbos were considered initially, but after a talk with Rob Stafford at Garrett Turbos we settled for a GT3076R unit. So straight away judging by the fact that it is part of the GT30 series range you can imagine it would be capable of flowing enough air to pop a stock SR20 that has 110,000+ kilometres on the odometer in no time at all.
Needless to say there is no point having a decent sized turbo like this and not turning the wick up because the engine can’t hold it. The vital statistics of the turbo deem it to be able to produce some serious boost, yet be fairly responsive, due to the smaller exhaust housing with a wheel trim designed to spool up quicker. Obviously on the 2.0 litre SR20 we have to be realistic so we will reserve judgment until it is done. One thing is for sure it will make some solid power figures on the dyno that will be double checked on the drag strip too. A few other turbo sizes and brands were considered, such as the T518Z and HKS GTRS but in the end the power figure we were going for called for something a little bigger. Garrett came to the party with their expertise and know-how and we feel confident that they will be able to supply great advice through the build and tuning process.
The exhaust housing we have selected is the 0.63 a/r to help a little with response on the 2.0 litre. The wheel in the turbine is 55mm in size and comes in the high flowing 84 trim. The compressor side of things features a 0.70 a/r housing, with a compressor wheel that is described as quick spooling. It measures in at 55mm and comes in a 52 trim. Capable of over 500hp, we will certainly be putting that to the test and seeing just how far this turbo can go, and what power it can produce.
The turbine housing is made of ductile Ni-Resist iron which has a nickel content of about 38%. Being able to withstand high exhaust temperatures much better than cast iron housings it will certainly be much more durable and capable of performing in all conditions. Similarly the turbine wheel is made from Inconel 713 that allows it to tolerate temperatures over 900 degrees Celsius.
The turbo looks awesome and the quality is exceptional. As the pictures demonstrate it certainly isn’t a small item and it has a substantial weighting to it also. But then again the few extra kilos over the puny T25G shouldn’t be too much of a hinderance when the big fella kicks in.
Garrett
Garrett have been making turbos for a very long time now, and while everyone associates them with providing blowers for manufacturing companies, they also have a thriving performance interest. With the huge budgets to hire the best engineers, fund the most R&D and testing, and a hand in many a race car turbocharger, Garrett have a good basis to be able to claim they know a fair bit about power production. We certainly did not mind their input when it came to helping us select a turbo that would fit what we wanted.
They have a huge range of off the shelf turbos designed for different applications and suitable for different applications. They also have the capablility to put together specially ordered and custom items for different specific applications to best serve a certain purpose. Such an ability makes it very easy to pick an off the shelf turbo and then tweak it slightly to better suit your engine and needs and without losing the whole character of the initial turbo. Many drag and circuit racing teams dream up all sorts of combinations of turbo with Garrett engineers advising along the way. Such dealings keep the Garrett turbo range ever changing, constantly refining and developing and always cutting edge.
Garrett GT3076R Turbo
Turbine Wheel:
0.63 A/R housing
55mm inducer wheel
84 trim
Compressor Wheel:
0.70 A/R housing
55mm inducer wheel
52 trim
550hp rating
External Wastegate
Engine Builder:
Indy So
IS Motor Racing
Unit 5, 5-7 Bermill St
Rockdale 2216
NSW Australia
Ph: (02) 9599 9918
Fax: (02) 9599 9981
Turbo:
Garrett
Honeywell Turbo Technologies
www.turbobygarrett.com.au
Check the website for your local state distributor. |
