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Nissan 370Z Forum (http://www.the370z.com/)
-   Forced Induction (http://www.the370z.com/forced-induction/)
-   -   Greddy Twin-Turbo In Development (http://www.the370z.com/forced-induction/6028-greddy-twin-turbo-development.html)

LiquidZ 07-28-2009 11:09 AM
I know for me, I want something with really quick spool time if I were to go turbo. I want an awesome low end for street driving, and an occaisional track day.

Mitsuyager9 07-28-2009 07:34 PM
Quote:
Originally Posted by in.the.dark (Post 128515)
Well, if you want to go that route, even the EvoIII 16g is going to be too large, but yeah that's exactly what I'm saying.

As for SixBone, GReddy is probably assuming that the person putting this kit on has dropped their compression ratio and will be running in these turbo's efficiency range.

For a street setup, the sweet spot would likely be somewhere in the T28 (not GT28) to 16g range in mitsu-speak. The spool would be instant and would hold to redline. I'm looking for a good compressor map. Anyone?
http://turbocarz.com/shapegsx/16g/compressor_plot.gifhttp://www.ztechz.net/sitebuildercon...6h-20g-cfm.gif
http://www.atpturbo.com/root/maps/im...rscompress.gif
yea i know even the evo 3 would be a little big but it gives you some room for lower compression if you wanted to do a rebuild someday...the small 16 or t28 would be a better option if you plan on keeping stock compression ratio for as long as you own the car...a 14b would be the closest if you wanted to run 12 psi...i know there are plenty of graphs but i dont feel like hunting right now

Mitsuyager9 07-28-2009 07:36 PM
Quote:
Originally Posted by LiquidZ (Post 128614)
I know for me, I want something with really quick spool time if I were to go turbo. I want an awesome low end for street driving, and an occaisional track day.
keep in mind if you have a manual trans then you can manipulate your powerband with the clutch to not have any lag if you are comfortable with your car (to a certain extent)

Brazilbro 07-28-2009 07:58 PM
having high compression will spool the 20g faster then if you where at 9.1 ish range. so i think that 16g would be really fast, probably hitting full boost at 3200rpm with the 20g at around 3600. You could always put the turbos that come stock on the 3000GT and have full boost at 2400rpm... would probably crap out though after 6k

LiquidZ 07-28-2009 08:55 PM
Quote:
Originally Posted by Mitsuyager9 (Post 129171)
keep in mind if you have a manual trans then you can manipulate your powerband with the clutch to not have any lag if you are comfortable with your car (to a certain extent)
I probably wouldn't be able to do that. I have never owned a turbo car.

Scribe 07-29-2009 08:05 AM
Quote:
Originally Posted by Brazilbro (Post 129188)
having high compression will spool the 20g faster then if you where at 9.1 ish range. so i think that 16g would be really fast, probably hitting full boost at 3200rpm with the 20g at around 3600. You could always put the turbos that come stock on the 3000GT and have full boost at 2400rpm... would probably crap out though after 6k
There is a lot of debate about whether the higher compression ratio significantly affects spool time. The short answer is, not really. The long answer is, higher compression will give you better off boost performance until you hit boost. Also the extra heat from compression causing additional pressure in the exhaust manifold to spool the turbo has to be significantly higher from a pressure ratio standpoint to make a significant difference, but that doesn't happen to that extent.

westpak 07-29-2009 10:36 AM
I agree there are a lot of technical mumbo jumbo that can be thrown around, but from personal experience going from the stock 10.3 CR on my 350Z to 8.8 CR on the built engine my butt did not notice any change in efficiency, boost kicks in hard and early breaking tires lose in 1st through 3rd gear and still scary in 4th

Sharif@Forged 07-29-2009 03:01 PM
20G's are used all the time on the 350Z. We've run even larger turbos on the VQ37 VVEL, and I promise you spool up and powerband isn't going to be an issue. Keep in mind, all of these turbos kits are using very small T25'ish sized flanges, so exhaust gas velocity isn't much of an issue.

I would much rather take the larger 20G over the more restrictive 18G. Compressor charts only tell you so much, but power output and spool vary drastically based on the application you are putting the turbocharger on.

LiquidZ 07-29-2009 03:49 PM
How do the more turbo savy people here feel about the 20G and its journal bearings? I'm no expert, but people have convinced be that ball bearings are always better for turbos.

Thoughts?

Mitsuyager9 07-30-2009 01:19 AM
Quote:
Originally Posted by LiquidZ (Post 130169)
How do the more turbo savy people here feel about the 20G and its journal bearings? I'm no expert, but people have convinced be that ball bearings are always better for turbos.

Thoughts?
ball bearing is always going to be faster on spool up but is more expensive than journal bearing...it all comes down to how much more do u want to spend for minimal performance gains..ball bearing will give you more of a crisp spool

Sharif@Forged 07-30-2009 09:32 AM
Quote:
Originally Posted by LiquidZ (Post 130169)
How do the more turbo savy people here feel about the 20G and its journal bearings? I'm no expert, but people have convinced be that ball bearings are always better for turbos.

Thoughts?
The spooling benifets of BB vs. journal are vastly overstated, IMHO. It's the size and structure of the turbo, and the displacement of the engine that has a much greater impact on turbocharger spoolup characteristics.

We just had a BB turbocharger on XKR's car take a dump after 3000 miles. Garret could not determine the cause of the failure. With Greddy, I have had modified turbos go bad, but haven't had any factory Greddy turbos go bad.

I am not suggesting that journal is more reliable than BB, but I am stating my experience to show that textbook discussions, can vary wildely from practical experience and application.

fstrnldr 07-30-2009 09:59 AM
Sharif if people want a SC set up why argue? just build them one!

http://i524.photobucket.com/albums/c...ormance/SC.jpg

i agree i would personally rather have a turbo set up, but nothing wrong w/ a good supercharger.

LiquidZ 07-30-2009 12:42 PM
Quote:
Originally Posted by Sharif@Forged (Post 130810)
The spooling benifets of BB vs. journal are vastly overstated, IMHO. It's the size and structure of the turbo, and the displacement of the engine that has a much greater impact on turbocharger spoolup characteristics.

We just a BB turbocharger on XKR's car take a dump after 3000 miles. Garret could not determine the cause of the failure. With Greddy, I have had modified turbos go bad, but haven't had any factory Greddy turbos go bad.

I am not suggesting that journal is more reliable than BB, but I am stating my experience to show that textbook discussions, can vary wildely from practical experience and application.

Thank you for that reply!

Shunya 08-01-2009 01:13 PM
anymore news or updates on these?

Nixlimited 08-31-2009 09:05 AM
Quote:
Originally Posted by Turbo Tuner (Post 101596)
As much as i hate to admit this, but Phimosis is correct and hit the nail on the head with that statement. As an owner of both a modded Viper GTS & 900HP single turbo MKIV Supra... there really isn't/wasn't any import sportscar out there out recently that was a blip on my jaded radar* But this new 370, address all the faults of the more refined second gen 350's with the HR motor, improves on everything else significantly, all while being lighter and having more of everything. It newer styling along with its refinement makes it a great buy and value at the price point i've seen local dealers selling it for. Very great value* It WILL be stealing a few porsche, vette and BMW buyers... ;)
I'll second this as a current M3 owner now perusing a Z site...


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