Turbo Market and Technology Update
 

Hey boys,

I am looking for someone to sum up the turbo tech and family developments over the last decade-ish or point me to a good resource. I've been out of the turbo game for a while and have fallen behind with all the new cool-kids lingo. What spurred me was looking over the available turbo options on the FA20Club kit and did not recall seeing the GTX family...ever.

My info and knowledge is a bit outdated. Basically, I read "Maximum Boost" by Corky Bell and when I had a boosted miata the cool turbos were the disco potato and T88. Im familiar with compressor maps, boost threshold, A/R...etc.

So what are the cool new turbos and tech?

The only thing you really missed was the introduction of billet wheels and Ti backplates. Back when you were up to speed Garrett and Turbonetics were the main suppliers to the aftermarket industry, but Precision turbo has taken over the last 4 years.

The GTX turbos are Garrett's newest line. The main difference is a billet compressor wheel. Side by side with the older GT ball-bearings, the compressor maps look a lot better. Much more flow up top, though you need to be running pretty high boost to see the benefit. You can make upwards of 450whp with spool better the older GT28s from a few years ago.

http://www.turbobygarrett.com/turbob...366-1_comp.jpg

http://www.turbobygarrett.com/turbob...9548-1comp.jpg

and a 2871 for reference since some kits use them

http://www.turbobygarrett.com/turbob...560-15comp.jpg

I've had 2 turbo Miatas. Doesn't get much funner than that. Engine management has changed much more than anything. With a Miata you could get by with an RRFPR, pump, base timing change and plugs. Now it's all Star Trek.

Yea great fun but scary as hell when you don't know what you are doing (behind the wheel) and have no $. Wish I had that car now after years of driver training and competition. 2000lb with 240whp, 2 way lsd and full aero... I was running a Greddy Emanage Blue. I wouldn't wish that crap piggyback on my worst enemy - 94 octane and I would struggle to get 150 miles out of her hahaha.

How about Borg Warner EFR turbos?

I had an AEM F/IC on my first turbo miata (I really liked tuning with this), and an EMU on my second. I ran an EMB on a KA-T. It blowed up but it was my fault.

If I was to turbo, I would be looking at maximizing two things, torque area under the curve, which can be seen from dynos and the time delta between off boost and boost threshold (transient). For a street based car that will see AutoX and track often, I really like a torque curve as Ptuning has demonstrated. That got me to looking at these turbos because 200 lb/ft at 2500rpm would just be disgusting!:

Borg Warner EFR 6258 (PINK) vs GTX2867

http://www.miataturbo.net/attachment...vs_efr6258-jpg

Nothing much has changed. Garrett brought out the 'X' range improvements because the old GT30/35 were pretty awful turbochargers on small'ish displacement engines (~£2L).

Borg Warner claim their EFR range is the best thing since sliced bread, but I haven't seen a huge amount of data on them.

I spent some time going through Garrett's compressor AND turbine maps the other week and came to the conclusion that for ~300hp the disco potato with the larger turbine housing (GT2860RS) is still probably the best Garrett turbo for an engine like this. The X versions were not an improvement, unless you don't want full boost until quite late in the engine speed range.

I think for above this power i'd probably take a punt on the EFR 6258 above, preferably twin-scroll with a well designed manifold.

Thought he new GTX series from Garrett is making great headway in the racing world ( Im going to be running twin GTX 4294R's on my current build), I would say that the custom turbo is really what has changed the game for the small Cube guys. If your knowledgeable enough, its not hard to have a small body, big heart turbo setup that will do significant damage with a small displacement engine.