GReddy T618Z
 

Does anybody have the compressor map for this turbo?

It's supposed to be an 18g stuffed into a TD06 housing. I was wondering why the GReddy turbo setup was so inexpensive, and this ancient technology explains why.

I tried to get them from Greddy, but they fed me a line about 'proprietary' and 'we'd be happy to build you a custom kit' blah blah blah. I emailed them back saying 'I don't need a frickin custom kit built by you guys, tune the one you already make for the Rx-8 for use on the low power motor!!!!!!!!!' and 'If I wanted a custom kit, I'd build it myself" blah blah blah :p

I just wanted the maps, to see if the turbo kit would be ok to tune for the auto.

I know that the T618Z is the turbo they use for the Skylines twin turbo setup kit that GReddy makes.. but that's about all I know or have been able to find on the net

Yes, they use that on the Skyline twin turbo and they use two 18gs on a Z twin turbo - yet for the RX-8 single turbo they use only one turbo that's small enough for twin applications . . . . . I know its safe but I think we can make a buttload more power from a more aggressive turbo like a GT40R @ 7 psi, though this would probably require a fuel system upgrade.

For the application, the T618Z is perfect. You must realize that the Greddy kit is for low boost applications.. If you saw that video of my driving, look at the spool times on my boost gauge.. it's almost instant spool up. The T618Z is probably good for up to 12psi, but no more.. after 12psi or so it'll produce too much heat to be any good.

-Jon

Stock fuel system should hold-up quite well. I am looking at the prospect of putting a large turbo on my car and so far, fuel delivery appears to not be a problem.

Engine Management actually seems to be the problem. I guess only experimentation will tell that for sure ;)

the e-manage that comes with the greddy kit is genius.. who knows.. they may sell the wiring harnes seperately in the future.. that way people don't have to splice and dice their ECU wiring to hook up an e-manage.

I don't think the turbo will hold you back as far as boost, but rather the compression - I'd be willing to bet we can see 10 psi safely.

After poking around and looking at 18gs (the T618Z is basically an 18G with a TD06 instead of TD05 housing) it looks like Garrett GTxxR series turbos of comparable size flow twice as much air.

As far as spool up, I'm not looking for instant, tire smoking boost - the power curve of the car comes on gradually, and I'd like my turbo to do the same, just amplified so by 6250 rpm it is rocketting all the way to 9300 rpm (remember, if the turbo spools by 4000 rpm, you still have 5000 rpm of boost left - the 6-speed will hold you back).

How would it work for a larger boost application? Can you adjust L/T spark? AFR? If so, how much does this puppy run by itself?

My greddy kit spools up to full boost around 2800-3000rpm at WOT.. i love it

the emanage cannot adjust trailing spark AFAIK.

GT40R at 7lbs of boost is a dog. The sweet spot for that turbo is like 16lbs of boost. Better to go with a smaller turbo that is going to spool quicker at low boost and make good HP like a GT35R or something similar.

Jason
www.rx8store.com

the emanage that comes with the greddy kit doesn't touch timing at all.

What about the T4 turbo that the other kits (PTP & SFR/SSR) will be using ? How are they compared to the T618Z ?

Since this is about turbos I have AN HKS GT 3037s BB 50 Trim do you guys think this turbo will fit And will be good ? this is an External w/g.

At 7-8 psi you would want to cross index the vertical axis at 1.4 to 1.6 (14.7+8/14.7)

http://www.atpturbo.com/root/maps/im...0rcompress.gif

As you can see, at a pressure ratio of 1.5 the GT40R is flowing about 300 lbs/min, and is within the central efficiency circle.

Now lets look at an 17c (since GReddy won't publish the 18g's maps) mounted in the TD06 instead of TD05 housing, just like the GReddy turbo, at a 1.5 pressure ratio

http://not2fast.wryday.com/turbo/map...u-td06-17c.jpg

You can see at a pressure ratio of 1.5 its barely pushing 120 lbs/min - if we upped the size to an 18g, which is marginally larger (remember, the 18g is a small turbo used in twin-turbo applications) we could expect to see, based on looking at the 17c and the 20gs (where the 18g in a TD06 would fit) between 150-250 lbs/min - still far less than a GT40R, with much slower spoolup (mitsu turbos are regular bearing, GTxxR are dual ball bearing turbos with amazing transient boost response).

As far as the comment about the T4 series turbos, again, ancient technology. IHI and Garrett GT (and GTxxR) series turbos blow those out of the water with regards to both response and flow. In general, the T04x series of Garrett turbos like boost to be around 1.6 or above, and that's at the very bottom of efficiency.


Concerning the GT3037, its barely running at a pressure ratio of 1.5 (180 lbs/min), this is for higher boost applications.
http://not2fast.wryday.com/turbo/map...1rcompress.gif

huh? :confused:

Yea what he said :eek:

To sum it up I think he says:
The GT40R would rock, even at 7-8 psi (almost 3 times as much air as the greddy turbo).
The GT30R is still better than the greddy turbo in airflow, but not much.

(Assuming that the 18g is somewhat similar to the 17c in performance).

It can though, right? I was thinking it could modify timing if the maps are set up to do it (and you wire it up to do it) but still couldn't independently adjust trailing spark. I think? :confused:

See, the thing is.. can it fit in the space where the Greddy T618Z goes. There's less than 1/2 inch clearance between my turbo and the aluminum heat shielding of my firewall.

Old technology or not, the turbo cetainly does its job well for low boost applications. Would it be my first choice for a custom setup? Prolly not, but I bet its a reliable unit they have found to work well for several of their kits. I'd rather have a quick spooling small turbo to get off the line quicker.

As it has been pointed out before, average HP, not peak, wins races.

I would be more worried about being able to feed enough fuel for 3x ammount of air flow. :)

The GT40R is ~$1500. Just for the turbo. Good for 700+ hps they say.

I just found a new hobby. Turbo maps. Looks like the Garett turbos are spanking bootie when compared to other turbos using similar psi.

Ok, couple things

The GReddy e-manage can control ignition timing and injector duty if you attach the proper harnesses - you can even change from MAF to MAP sensor if you want

As far as the turbos, the reason the GReddy kit is cheap is because its not using a monster turbo, yes it gets the job done, yes it is worth every single penny (in my opinion).

However, the GTxxR series turbos are ALSO worth every penny - I had a GT3540R on my RX-7 and HOLY SHIT it was insane - boost response was ridiculous, even compared to my Big 16g I had on my 4g63 GSX Eclipse - and it had more top end - these are F1 technology turbos - they spool up faster and flow way more air than traditional turbos, but you pay for it.

As far as clearance, these turbos aren't that much bigger than an 18g - I'm positive you can fit it, since some people are using T4s (which are bigger, but flow less air and take more time to spool up).

Fuel is going to be the real issue, like twospoons said.