Project: Ultimate Response GTS-T

[klys]

well my turbo went.. so time for an upgrade.

I'm slowly going for an GT3076R with a top mount manifold.

I just got my Nistune and an Innovate LC-1 Wide band from Ztune.ca so I'll finally be able to tune on the fly!

[klys]

well I pulled out my old HKS turbo today and I indeed need to replace the bearing.

I started putting in a:

STOCK gts-t turbo hehehe times are Hard.

should be finished tomorow...

I'm still shopping for the Garrett
thanks Opus!

[Skym]

The best responding setup I've experienced on a RB20DET, was a stock RB20DET engine with rebuilt stock turbo (slightly bigger than factory turbo) and stock intake, exhaust. The kick in the pants (response) was amazing when backing off throttle or accelerating on the motorway (very aggressive) with near to stock boost level.

Similar to Max D's R33 with HKS 2540, which is very responsive -

http://www.youtube.com/watch?v=rYa1Ux4qOwM

[klys]

yeah I know bigger will be laggier, but I intend to do my homework before putting in a bigger turbo.

tilll winter, stock will have to do. and I'm sure it will

[Skym]

It's sometimes better to go custom spec turbo from turbo rebuilder than off the shelf if chasing response.

[klys]

well stock turbo is in boourns... I want my torque back hehehe

[nelsonmxmarc]

rebuilt stock turbo (slightly bigger than factory turbo)

What do you mean by this? Is the turbo bored out or something?

I've been watching this thread for a while with hopes to hear some good news to a responsive RB20 turbo setup..

The one thing i want to avoid is an rb20 hitting peak boost at 4500 rpm :S

[klys]

I don't know from where in this thread you quoted the above, but it's possible to change either the compressor or turbine housing to get a different A/R ratio which will be able to flow more air in the engine

[Skym]

It was from my post above. Rebuilt RB20 turbo has a new aftermarket CHRA (Centre Housing Rotating Assembly or centre part of turbo), compressor wheel, exhaust wheel (steel exhaust wheel). Stock compressor and exhaust housings are machined to suit the slightly bigger compressor wheel, exhaust wheel. It's basically a stock turbo from a VG30DET with RB20 turbo compressor, exhaust housings.

This rebuilt RB20 turbo with intake, exhaust, BOV mods, stock dumppipe, stock intercooler has full boost at around 3500rpm (stock is around 2500rpm-2800rpm), but pulls all the way to 7500rpm (peak hp), where it hits the stock rev limiter. In that state (stock ECU maps), engine produces around 275hp at 12psi (equivalent of running 1.2bar with stock turbo). With ECU retune (up to 30hp gain), close to 305hp.

[nelsonmxmarc]

Thats incredible.. i'll definitely have to look into this as i have a spare rb20 turbo laying around from my parts car. Would definitely be more advantageous, in my opinion, then having to deal around the lag of a larger, more powerful turbo.. Where is this possible to get done? I'm not very familiar with anyone in Montreal, rather, Canada, that deals with turbo rebuilds. And cost wise, is it an advantage?
Thanks for the reply Skym

Klys must have an idea!

[Skym]

A rebuilt turbo on RB20DET at half throttle is amazing acceleration wise, as you need to have car in straight line, or you'll be in trouble. It's like stock acceleration but more violent / quicker.

Stock RB20 turbo has a T3 55 trim compressor wheel, going by the size of compressor wheel (42mmx59mm) in a 0.50 A/R compressor housing. Upgrade wise they seem to use a T3 60 trim (46.5mmx60mm) in the same housing on a rebuilt RB20 turbo, which is similar in compressor wheel size to stock VG30DET turbo, that from memory has bigger A/R compressor, exhaust housings. The rebuilt RB20 turbo uses a TB03 CHRA, which I found out from reasearch, is the same CHRA as used on non ballbearing VG30DET turbo. Exhaust wheel upgrade on rebuilt RB20 turbo is 58.9mmx48.7mm with 72 trim T3 shaft. Stock RB20 turbo = 0.4 A/R exhaust housing. Stock ceramic exhaust wheel is 51mmx43mm on RB20, RB25 stock turbo's.

From a dynograph, 11.3psi-12psi is at 6000-7500rpm. It's more like 10.3psi at 3500rpm and rises to 11.3 psi at 4500rpm with stock ECU tuning, "stuffed" stock RB20 wastegate actuator. Lean A/F (12.85-13.43 A/F at 3500rpm, where it should be 11.6:1) doesnt help boost level wise with stock engine ECU maps and neither did the stuffed stock wastegate actuator. But is safe (11.6:1) at 7500rpm. So budget to do ECU retune (Nistune) at same time to get lower rpm A/F ratio, ignition timing, etc sorted.

There's a few turbo businesses in Canada, search my post's, as I posted them a while back.

The benefit is rebuilt RB20 turbo uses all of the factory gaskets, factory oil, water feed, return, etc. Also need a new O ring for oilfeed. It looks stock to the eye but engine produces more hp. Perfect sleeper mod.

[klys]

Humm I resolve most of the leaks...

man this is quite fun now.. not as much torque as with the HKS unit, but boost seems to build a bit faster.

0.8 bar at under 3000RPM steady to 7000 and I haven't touched the tune yet.

[Skym]

ECU tune is probably richer, if it's suited to HKS turbo. Going from 13.43 to 12.85 A/F ratio makes boost rise 0.3 psi. Imagine the gains when dropping to 11.6:1.

[RWD_GTR]

none of the pics work in this thread for me

[ARC240]

Klys, just saw a video of this car on YouTube...sounds amazing!!! I love it.