I've been overlooking the Greddy 20g since their turbos are smaller than a GT30 on the APS extreme or the GTM kits.

But with the lackluster high boost performance at the cost of lag of said kits, its got me wantin to take a closer look at the 20g's which might not be as small as I thought.

I've checked thru all the shop builds and searched as well as I can on this forum, but I cannot find anone on a 20g kit that has really pushed it.

Anyone know what a pair of 20g's will do strung out?
Their wheel sizes are 52/68 and turbine 55/65

3071 is 53/71 and turbine 52/57 with a T25 flange (http://www.ztechz.net/id1.html)
*** makes me wonder if the T25 is only 52/57 while the T3 is 55/60, is that the same smaller turbine used on all the GTM kits????****

Ideally a dyno like this but with a 3.5L and just more boost



Using this calc
http://www.squirrelpf.com/turbocalc/index.php
these stats (based on other ~800 hp dynos)
3.5L
11.5 AFR
redline: 7500
peak power: 6000
peak boost:5000
min boost:2500


I get this map. Looks AWFUL if trying to hit 800 hp, near impossible.


as compared to a pair of GT3071s


A single 4202 like Hal is using looks sooo nice



So real world, can 20g's make 800?

as as side note, here is the compressor map of a 4.0l with twin gt35s trying to hit 1000 hp
redline 7500
peak power:6500
max boost 5800
min boost:2500


change a few parameters and they look like a great match
redline 9500
peak power:8200
max boost 7000
min boost:3500

 

My FP Green (similar cfm specs to 20g) on my 2.0L 4g63 pulled 392whp on 20psi with no alchy, lots of potential on a twin 20g set up on the VQ. Hope you're looking for usable horsepower, not bragging rights. If so, these are great street turbos, high potential on pump with the right tune.

 

looking for a 135+mph trap, so streetable HP isnt main concern as is top end. The car is not a daily, i'm not a stop light racer and a broad power band can sit at traffic lights as well as big boost car.

I've seen high 300 on those FP greens on subys. I've studied enough 2L cars to know that those #'s dont really transfer bc they use bigger housing, tubular manifolds, and are right on the exhaust ports. I posted a link of a 2L Evo making 900 hp on a single 67mm turbo. If we could do that, it would be a simple choice.....

 

I too am curious how folks have done with their 20G Greddy turbo set-ups. I have them on my current set-up (2003 VQ35DE Stock Bore and stroke) and have yet to get the monster tune to truly demonstrate the potential of these turbos.
I am currently running a base tune that leaves something to be desired. So far they achieved 580 rwhp at 15psi and 640 rwhp at 19 psi on 93 octane (No Meth or Nitrous). AFR currently is 10 (instead of 11.5), so I know it has plenty more in it, once re-tuned. Its running quite a bit rich but still is nothing to shake a stick at.
The only unfortunate thing is I was denied me my rights to a dyno sheet. Oh well. Won't matter much as I intend to get a re-tune very soon anyway.
Just thought I would share my experience w/20G's.

 

640 on pump is very nice. I assume a dynojet? if so, just under 600 on a DD.

Are you going to retune at the same boost or go for more?

Thanks!

 

It was on a Dyno Dynamics to achieve those numbers. I will be re-tuning at same boost with proper AFR and hopefully improve on some of the numbers. But I will also be going higher to make real use of the 20G's. Tuner will decide how high, but I will also be using Methanol as a safety net, the higher in boost we go.
Not trying to break any records but just to see what the 20G's are capable of. Then I will run at a lower setting for DD and track events, with the ability to turn it up at a moments notice and drop the hammer on some unsuspecting challenger.

 

link from greddy web on a GTR 35 made 778whp with 20G

http://2.bp.blogspot.com/_1agu36yXDm...8Medium%29.JPG

link 2
http://greddy-usa.blogspot.com/2009/...e-778-whp.html

 

DD true numbers or simulated for DJ?

With measly 18G's I do

13psi 605whp
15.5psi 652whp
17psi 675whp
20psi

OP-when my 18G's die I'll look into the 20G setup more, although to be honest I never have done research on it, and dont even know how easy/difficult it would be to upgrade the standard Greddy kit.

 

Alberto, are your numbers DJ?

 

Yes

I have DD numbers, but they are before the retuner and are about 30-40whp lower per psi than the car does now.

 

- Holy Moly those numbers are impressive.

 

I believe the Greddy's for our cars are TD05-20G. The TD05 turbine is 49/56 mm. The TD06 turbine has the dimensions that you listed.

Still, the 3071 turbos are just a little bigger than the Greddy TD05-20G turbos, which is actually why I chose them for my build.

More good links.

 

[subscribing] great thread [/subscribing]

not too familiar but i heard its unfortuantly not jsut a stright turbo swap....and i would assume you would be >700whp ...ive seen that out of the 18Gs... but probably not abused like you do,

 

St8dum1,

I ran the numbers at the Squirrel Performance site. I used 0.42 for BSFC, 0.94 for VE, and 105 for intake temperature, and things look better.

Still, I think that BSFC is a bit conservative for our motors.

EDIT: St8dum1, the default temperature's are too high, and they significantly change the data. If you re-run the data for the Greddy turbos using 105 or 110 degrees, you will see that they should get you to 800 crank hp, which puts you north 700 whp. Per the map, 900 crank hp might be do-able with a good intercooler.

EDIT EDIT: The default VE values are way off for our motor. A N/A 4 valve per cylinder motor is somewhere between 95%-99%. Add forced induction onto that, and the VE is over 100%. At first, you may ask "how can it be greater than 100%," at least I did. It's the way VE is defined:

"[V]olumetric efficiency is a ratio (or percentage) of what volume of fuel and air actually enters the cylinder during induction to the actual capacity of the cylinder under static conditions. Therefore, those engines that can create higher induction manifold pressures - above ambient - will have efficiencies greater than 100%." "Volumetric efficiencies above 100% can be reached by using forced induction such as supercharging or turbocharging."

http://en.wikipedia.org/wiki/Volumetric_efficiency

EDIT EDIT EDIT: After more research, I think the website wants the naturally aspirated VE value before the turbos are added.

 

This winter when I build my motor I will have Blouch Turbo transform my 18g's into 20g's. Ill report back once the car is back on the road.

 

The horsepower numbers that you enter in the calculator are crank HP, correct? (Not whp, or did you add in a drivetrain loss already). That site doesn't have the 2860RS with the .86 AR. Even with the .60 AR it seems my turbos have some headroom up to 20 psi. We'll see... Str8dum1, the other parameter you may want to consider as you deliberate on your upgrade path is the total area under the torque curve in the rpm range you expect to operate in. You may find the results unexpected.

 

OP,
finally getting rid of the vortech huh lol

Great info in this thread!.. it got me thinking now... powerlab on build motor or the 20gs... great, more money to spent

 

theres also the HTA upgrade from Forced Performance for Greddy Kits. theres a 82mm, 76mm, and a 72mm upgrade option... Still waiting on results/word from Sharif on those. I called up there and spoke to Forced Performance and they say its better than the 20g option ..

I think one of you more knowledgeable guys need to call up there and translate what he told me into plain English for us common folk please ..lol
Forced Performance: (972) 984-1800
www.forcedperformance.com

taken from: https://my350z.com/forum/forced-indu...upgrade-5.html

 

OP has been doing quite a bit of research, maybe over thinking a few things, but he sure has been looking at "big"(Er) turbo options... he needs to stop dragging his feet and really get his build started

 

18g is a 40lb/min wheel, 20g is 44lb/min. Not that much different.