GT2560 - 261 ft-lbs, 272 hp - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 09-17-2011, 08:45 PM   #1
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default GT2560 - 261 ft-lbs, 272 hp

GT2560
ETD shorty tubey manifold
BEGI custom divorced downpipe
Custom 2.5" exhaust with metal cat
VVT head, mild porting
VICS manifold
8.6:1 Supertech pistons
15 psi midrange, tapering to 14 psi at the top.

conditions: sea level, 31*C
SAE correction applied:



VVT produced large gains in torque.
15 psi likes more VVT retard than 10 psi.
Turbo didn't like moar boost. Gains were small beyond 15 psi, even in the midrange(!).

It didn't lose torque going down from 12.5:1 AFR to 11:3:1 AFR, and lost below that.

Note flat power from 6000-7300 RPM. I think this is due to VVT. Savington sees flat power with his VVT and Blox intake mani. I suspect it's due to VVT, not the mani.

160 ft-lbs @ 2450 RPM
200 ft-lbs @ 3500 RPM

I will miss that low end if I go to a bigger turbo.
Attached Thumbnails
GT2560 - 261 ft-lbs, 272 hp-jason-dyno-sep-17-2011-sm.gif  

Last edited by JasonC SBB; 09-18-2011 at 01:05 PM.
JasonC SBB is offline   Reply With Quote
Old 09-17-2011, 08:47 PM   #2
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,175
Total Cats: 2,575
Default

Very nice daily driver powerband
18psi is offline   Reply With Quote
Old 09-17-2011, 08:57 PM   #3
Elite Member
iTrader: (7)
 
samnavy's Avatar
 
Join Date: Apr 2006
Location: VIRGINIA BEACH, VA
Posts: 6,020
Total Cats: 175
Default

That **** is awesome, and should last forever.
samnavy is offline   Reply With Quote
Old 09-17-2011, 09:15 PM   #4
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

dtalog

Attached Thumbnails
GT2560 - 261 ft-lbs, 272 hp-jason-dyno-15-psi-datalog.gif  
JasonC SBB is offline   Reply With Quote
Old 09-17-2011, 09:20 PM   #5
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,362
Total Cats: 1,323
Default

Quote:
Originally Posted by JasonC SBB View Post
Note flat power from 6000-7300 RPM. I think this is due to VVT. Savington sees flat power with his VVT and Blox intake mani. I suspect it's due to VVT, not the mani.
Haven't I told you that this isn't correct before, Jason?

Purple line is my first built motor (84mm 8.6:1, BP4W head, GT2871R). Blue line is my second built motor (83.5mm 8.6:1, VVT head, GT2871R) with VVT at full retard.



Now look at the old motor vs. the new motor w/ VVT advanced under 4500rpm (huge low-end gains) and the Blox manifold installed (huge top end gains). VVT is at full retard from ~5000rpm up, just the same as it was in the blue/purple chart - if VVT were causing the top-end gains, they would have appeared in the blue/purple chart - but they didn't. The lighter lines under it are the lines from the previous visit, which was VVT and the Blox manifold at 14psi on 100 octane.



All four torque curves synthesized into one:



See how the torque curve extends flat to 6000rpm on both of the Blox curves, but the torque drops at 5000 on the stock manifolds? Now look at your torque curve - the torque drops at 5k.

VVT does not have any effect on high-end torque - the intake manifold makes that difference, and I've never seen any data to disprove that.
Attached Thumbnails
GT2560 - 261 ft-lbs, 272 hp-bp4w_vs_vvt.jpg   GT2560 - 261 ft-lbs, 272 hp-img00011-20100410-0833.jpg   GT2560 - 261 ft-lbs, 272 hp-4enginecomparison.jpg  
Savington is online now   Reply With Quote
Old 09-17-2011, 09:28 PM   #6
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Ah cool, that explains things, thanks.

Anyone seen a bone stock dyno of a JDM or EUDM 2001+ motor?
The flat torque from 5000-6000 should be visible there too.
JasonC SBB is offline   Reply With Quote
Old 09-17-2011, 09:36 PM   #7
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

I started out having the same VVT angle vs. RPM curve, from 0 psi to 15 psi.
I used a curve that I had generated by logging AFR at 10 psi. I looked for increases in AFR, which topped out at a certain point.

So as I retarded the VVT curve at 15 psi, from the 10 psi settings I had before, I saw huge gains, up to a certain point. And then retarding by a further 4 crank degrees saw no change. I kept it there.
JasonC SBB is offline   Reply With Quote
Old 09-17-2011, 09:44 PM   #8
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Its funny how the GT2560 will happily generate mid levels of boost from like 2700 to 3250 RPM, with a slow rise in boost and torque. Then suddenly at 3250 RPM / 160 kPa it turns the corner and boost rapidly rises to 200 kPa.

My 2560 makes 160 ft-lbs at 2500 RPM and 170 ft-lbs at 3000, which is more than Sav's 2871, then we both make 200 ft-lbs at 3500. And then of course the 2871 takes off after that.
JasonC SBB is offline   Reply With Quote
Old 09-17-2011, 09:55 PM   #9
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

BTW 262 tq at 202 kPa with a 1.8L yields:

72 ft-lbs per atmo per L. That's the magic number one has to hit.
JasonC SBB is offline   Reply With Quote
Old 09-18-2011, 12:58 AM   #10
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Here's an interesting comparison. Ian has a GT2560 on a 99 head. We both have a VICS manifold. Note the same "turning the corner", albeit at 3100 RPM instead of 3200 RPM.
His spoolup on his 99 is better than mine on my VVT, and his HP droops above 6000 RPM and mine stays flat.



And then Hustler's 0.86 GT2860 :

150 ft-lbs @ 3000
195 ft-lbs @ 3500
Albeit with inflated dynojet numbers.
Attached Thumbnails
GT2560 - 261 ft-lbs, 272 hp-bt2-15psi.jpg  

Last edited by JasonC SBB; 09-18-2011 at 01:06 PM.
JasonC SBB is offline   Reply With Quote
Old 09-18-2011, 01:02 PM   #11
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

More comparisons against Ian's GT560 on a 99 head:

His 99 head spools earlier than my VVT, but my VVT holds power much better at the top:

(both have SAE correction turned on. Same shop same dyno, about a year apart)

boost curve again shows his 99 head has better spoolup; and I'm running less boost


Differences that may account for spoolup / topend power holding, aside from VVT head:
- ambient temps may have delayed my spoolup - 87*F vs 77*F (doesn't seem like much tho)
- I have an ETD shorty mani vs. FM mani (may explain better topend but not delayed spool)
- I have an exhaust cam gear, retarded 5* (crank degrees) - could help explain topend but should not delay spoolup
Attached Thumbnails
GT2560 - 261 ft-lbs, 272 hp-dyno-compare.jpg   GT2560 - 261 ft-lbs, 272 hp-map-compare.jpg  
JasonC SBB is offline   Reply With Quote
Old 09-18-2011, 02:16 PM   #12
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Is this flywheel horsepower? The dyno chart at the top says it is flywheel.


Quote:
Originally Posted by JasonC SBB View Post
Its funny how the GT2560 will happily generate mid levels of boost from like 2700 to 3250 RPM, with a slow rise in boost and torque. Then suddenly at 3250 RPM / 160 kPa it turns the corner and boost rapidly rises to 200 kPa.

My 2560 makes 160 ft-lbs at 2500 RPM and 170 ft-lbs at 3000, which is more than Sav's 2871, then we both make 200 ft-lbs at 3500. And then of course the 2871 takes off after that.
You know, my 3071 does pretty much the exact same thing. Slow rise to 10psi then rapid rise to 25.
Faeflora is offline   Reply With Quote
Old 09-18-2011, 02:25 PM   #13
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,175
Total Cats: 2,575
Default

same here:

3076 .82
Attached Thumbnails
GT2560 - 261 ft-lbs, 272 hp-untitled.png  
18psi is offline   Reply With Quote
Old 09-18-2011, 02:32 PM   #14
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

I see some SPOOOOOL nig!
Faeflora is offline   Reply With Quote
Old 09-18-2011, 05:01 PM   #15
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Jason,
What cam angles were you running right around spoolup?
y8s is offline   Reply With Quote
Old 09-18-2011, 05:33 PM   #16
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Datalog of spoolup sweep, from 2200-4200 RPM.
I played with timing for spoolup, but ran out of time and forgot to check if VVT settings could produce better spoolup. I can check it on the street tho.

Bottom third of screen is cam angle, and wasategate duty cycle.


Note that the AEM displays VVT angle as degrees of retard. So 48* is max retard, and 0 is max advance. Right around spoolup, where the cursor is, I'm running at about 24*, so right in the middle between max retard and max advance. You will also see that the WG duty cycle is close to 100%.
Attached Thumbnails
GT2560 - 261 ft-lbs, 272 hp-spoolup-sweep.gif  
JasonC SBB is offline   Reply With Quote
Old 09-18-2011, 05:38 PM   #17
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Quote:
Originally Posted by Faeflora View Post
Is this flywheel horsepower? The dyno chart at the top says it is flywheel.
It back-calculates it from the hub torque and gearbox/diff ratios. It does not attempt to add in estimated transmission losses. Thus it is "wheel torque", translated to the flywheel.

Quote:
Originally Posted by Faeflora View Post
You know, my 3071 does pretty much the exact same thing. Slow rise to 10psi then rapid rise to 25.
So does this VW / Disco Potato:
https://www.miataturbo.net/showpost....0&postcount=31

Slow rise to 3300 RPM / 150 ft-lbs, then rapid rise to torque peak.
JasonC SBB is offline   Reply With Quote
Old 09-18-2011, 05:50 PM   #18
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by JasonC SBB View Post
Here's an interesting comparison. Ian has a GT2560 on a 99 head. We both have a VICS manifold. Note the same "turning the corner", albeit at 3100 RPM instead of 3200 RPM.
His spoolup on his 99 is better than mine on my VVT, and his HP droops above 6000 RPM and mine stays flat.



And then Hustler's 0.86 GT2860 :

150 ft-lbs @ 3000
195 ft-lbs @ 3500
Albeit with inflated dynojet numbers.
I need to cough up the coin and get a real dyno chart on a Mustang Dyno, instead of whoring that barrel-roller dyno chart. I bet the numbers would be a bit better for my car.
hustler is offline   Reply With Quote
Old 09-18-2011, 06:26 PM   #19
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Quote:
Originally Posted by JasonC SBB View Post
Datalog of spoolup sweep, from 2200-4200 RPM.
I played with timing for spoolup, but ran out of time and forgot to check if VVT settings could produce better spoolup. I can check it on the street tho.

Bottom third of screen is cam angle, and wasategate duty cycle.


Note that the AEM displays VVT angle as degrees of retard. So 48* is max retard, and 0 is max advance. Right around spoolup, where the cursor is, I'm running at about 24*, so right in the middle between max retard and max advance. You will also see that the WG duty cycle is close to 100%.
I bet the cam angle accounts for at least some spool left on the table.

I run a lot of advance above 3000 and taper off as I get above 4000 and it makes a big difference in low end.

A lot = 38 degrees.

On my car it didn't make a big difference what advance I ran below 2500 but the dyno plot barely starts there so it's hard to glean any useful information.

were you at full retard above 6000 RPM? I get the same flat power curve from 6300 to 7k.
y8s is offline   Reply With Quote
Old 09-19-2011, 01:51 AM   #20
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

VVT through whole RPM range.
Hits full retard (48*) at 6400 rpm.

Attached Thumbnails
GT2560 - 261 ft-lbs, 272 hp-vvt-plot.gif  
JasonC SBB is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
VE values too low? compuw22c MEGAsquirt 4 09-12-2015 08:42 PM
Motor Mount Install miatamania General Miata Chat 16 09-12-2013 01:42 PM
Set of 4 Yokohama ADVAN Neova AD07 Tires from $272 + $53 s&h miatauser884 Insert BS here 2 03-01-2010 10:22 PM
Get serious about VVT AbeFM Engine Performance 13 11-11-2009 02:15 PM
More ACT + Spec stuff miatamania General Miata Chat 45 01-16-2007 09:11 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:51 PM.