Gt2871 dyno - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 07-24-2010, 08:27 PM   #21
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Did you **** with the timing at all?
Faeflora is offline   Reply With Quote
Old 07-24-2010, 09:28 PM   #22
Junior Member
 
Join Date: Jul 2008
Posts: 114
Total Cats: 0
Default

I haven't looked at too many 2871 dynos, but it seemed like it took a while to spool then once it got there, it dropped off. It looked as if the turbo was too big for the engine, but without the peak numbers, which would indicate a lack of flow.

It sounds like the first thing to do will be to get your exhaust flowing better, then maybe an intake manifold followed by larger valves
NickC is offline   Reply With Quote
Old 07-24-2010, 11:34 PM   #23
Senior Member
iTrader: (10)
 
Join Date: Oct 2005
Posts: 718
Total Cats: 5
Default

I dont know if this is my best plot, but this is my set up. 1.8 built. BEGI cast mani. +1mm valves, 3" DP and exhaust.
This is about 1.5yrs old. I also have a gutted 99 intake. Thats not helping my spool.
gt2871r.

My point is, I believe you can do better. Esp with it being a 1.9??
Attached Thumbnails
Gt2871 dyno-315hp.jpg  
TURNS101 is offline   Reply With Quote
Old 07-25-2010, 02:07 AM   #24
Elite Member
iTrader: (8)
 
Join Date: Sep 2006
Location: Severn, MD
Posts: 1,927
Total Cats: 5
Default

Dynos make what they make. Any dyno operator can **** with the numbers as he pleases and one of them leave their baseline as is. I've been on dynojets that are spot on with a fairly close drivetrain loss estimate and I've seen Mustang dynos that were jacked up from their "heartbreaker" numbers.

You get a baseline, you get it tuned, you get a final number, you compare the difference. That's what dynos are for.

I'd much rather have a dyno operator that knows what the **** he's doing than some moron on the "most accurate dyno in the world".

And BTW, any good tuner knows the tuning differences from Dynojets that most owners don't set up for load (though they can), and a street tune. If you think you need a load bearing dyno to properly tune a car you really need more tuning time to know what the hell you're doing.
fmowry is offline   Reply With Quote
Old 07-25-2010, 02:30 AM   #25
:(
iTrader: (7)
 
Join Date: Jul 2006
Location: nowhere
Posts: 8,281
Total Cats: 2
Default

gj wes
magnamx-5 is offline   Reply With Quote
Old 07-25-2010, 03:36 AM   #26
Junior Member
 
Join Date: Jul 2008
Posts: 114
Total Cats: 0
Default

Quote:
Originally Posted by TURNS101 View Post
I dont know if this is my best plot, but this is my set up. 1.8 built. BEGI cast mani. +1mm valves, 3" DP and exhaust.
This is about 1.5yrs old. I also have a gutted 99 intake. Thats not helping my spool.
gt2871r.

My point is, I believe you can do better. Esp with it being a 1.9??
BEGI cast mani is ambiguous, but I'm assuming you mean the turbo/exhaust manifold. I'm not super experienced with this stuff, but your torque curve doesn't look too much better than his. Torque (minus velocity-based losses) is directly related to acceleration, so a flat torque curve will yield a nice, smooth "close-to-constant" acceleration. I don't imagine that weird mountain looking thing going on in there is very smooth to drive.

I think a good intake manifold like the honda skunk w/ BP flange welded on, should prevent the torque curve from going limp like that without taking away too much low/mid-range.
NickC is offline   Reply With Quote
Old 07-25-2010, 04:00 AM   #27
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Damn guys quit gangbanging the frikken intake manifold wagon. There are lots of 350+ hp miatas out there with stock intake manis.

There's lots of other **** in the car that affects the numbers not to mention the frikken tune, the damn boost control system, heatsoak etc...

You know for all the cheering about intakes I haven't seen -one- real back to back same day pull with the ONLY change being the intake swap out.
Faeflora is offline   Reply With Quote
Old 07-25-2010, 04:16 AM   #28
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,175
Total Cats: 2,578
Default

Quote:
Originally Posted by faeflora View Post
Damn guys quit gangbanging the frikken intake manifold wagon. There are lots of 350+ hp miatas out there with stock intake manis.

There's lots of other **** in the car that affects the numbers not to mention the frikken tune, the damn boost control system, heatsoak etc...

You know for all the cheering about intakes I haven't seen -one- real back to back same day pull with the ONLY change being the intake swap out.
Show us ALL THE examples.
If he's holding a pre-set pressure level all the way to redline what the **** else would you IMPROVE on in the boost control system?

There are many here that have shown before and after dyno sheets. The numbers don't lie.

If you're going to go against the majority of members on here in your way of thought you better provide some damn good examples to validate your reasoning.

So far only thing you've shown is how badly someone could **** up a frame rail with a hack saw.
18psi is offline   Reply With Quote
Old 07-25-2010, 04:17 AM   #29
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 faeflora View Post
You know for all the cheering about intakes I haven't seen -one- real back to back same day pull with the ONLY change being the intake swap out.
Not the same day, but the same dyno. Only other change is VVT, but I have another dyno graph proving that doesn't make more than 5-10whp difference.

Name:  IMG00011-20100410-0833.jpg
Views: 10
Size:  62.3 KB

So yeah, only like a ~30whp difference.
Savington is offline   Reply With Quote
Old 07-25-2010, 12:12 PM   #30
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Allright, here's a few:

http://flyinmiata.com/tech/dyno.php

http://forum.miata.net/vb/showthread.php?t=342323

And here, Jay's done it.

And that's just FM charts and you know there's many "FM cars" more out there which aren't on that website.

Sav, I saw your graph and I "believe" but for the $, when it comes time for me to try one out I will do a same day back to back.

18psi if you really believe that having an IM is a prerequisite 300+whp that's asanine. If your turbo can handle it, moar boost will get you there. Don't be obtuse. As I said before, have you considered the frikken map? He didn't reply to my question about timing. Maybe his map is fucked, maybe the timing is untuned. Regardless, he can easily see over 300 with bigger injectors and more fuel. BTW it was a sawzall...

I also don't like this **** too much because while the intake is not a closed system, it seems like the forum (collectively) is forgoing engineering. Does anyone know what the volume of a stock intake + runners is? What is the volume of X replacement? With the runner length, what power band should we expect to improve? What's the volume of the plenum and how does it compare to a stocker?

I understand strapping one on and seeing what kind of difference it makes but who knows, maybe the results would be much more dramatic if it was sized properly and most of the intakes I've seen out there are smaller than what the maths tell me they should be.
Faeflora is offline   Reply With Quote
Old 07-25-2010, 03:57 PM   #31
Elite Member
 
Join Date: Dec 2008
Location: Colorado
Posts: 1,669
Total Cats: 36
Default

Quote:
Originally Posted by NickC View Post
BEGI cast mani is ambiguous, but I'm assuming you mean the turbo/exhaust manifold.
If you say BEGi cast mani, it's known what you're talking about.
Sparetire is offline   Reply With Quote
Old 07-25-2010, 04:56 PM   #32
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 faeflora View Post
I also don't like this **** too much because while the intake is not a closed system, it seems like the forum (collectively) is forgoing engineering. Does anyone know what the volume of a stock intake + runners is? What is the volume of X replacement? With the runner length, what power band should we expect to improve? What's the volume of the plenum and how does it compare to a stocker?

I understand strapping one on and seeing what kind of difference it makes but who knows, maybe the results would be much more dramatic if it was sized properly and most of the intakes I've seen out there are smaller than what the maths tell me they should be.
So your argument is that because we cannot spend the money to fully optimize the intake manifold, we shouldn't bother at all? I've gotten a quote for the kind of engineering work you're talking about, and it goes way, way beyond plenum size and runner length. Throat angles, cross-sectional area at several points down the runner, portmatching, etc, etc. Just the design quote was more than I have into my current IM, and then they wanted like 2-3x that for sheetmetal fabrication. It might get me 60whp instead of 30, and it might get me 35. Someday when I **** gold I'll go have that done, but in the meantime I'll put my money into other places.
Savington is offline   Reply With Quote
Old 07-25-2010, 05:31 PM   #33
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,175
Total Cats: 2,578
Default

Quote:
Originally Posted by faeflora View Post

18psi if you really believe that having an IM is a prerequisite 300+whp that's asanine. If your turbo can handle it, moar boost will get you there. Don't be obtuse. As I said before, have you considered the frikken map? He didn't reply to my question about timing. Maybe his map is fucked, maybe the timing is untuned. Regardless, he can easily see over 300 with bigger injectors and more fuel. BTW it was a sawzall...
You can raise pressure or increase flow. Or both.
Reason people on here get bigger turbo's, head work, cams, tubular exhaust manifolds, and free flowing exhausts is why?
FLOW.
More flow = less heat = more power at less pressure.


I get your point about no one REALLY doing thorough tests on stock im vs the sheetmetal ones, but then no one REALLY did any tests on the absurdflow and other tubular exhaust manifolds either to prove that they flow better than the BEGi log, yet everyone and their mother will agree that they flow more.
18psi is offline   Reply With Quote
Old 07-25-2010, 07:04 PM   #34
Junior Member
 
Join Date: Jul 2008
Posts: 114
Total Cats: 0
Default

Quote:
Originally Posted by Sparetire View Post
If you say BEGi cast mani, it's known what you're talking about.
Still ambiguous despite context clues and assumption through understanding of general forum dialect, I still dislike that I thought he may have had a BEGi cast intake manifold when I first read it ^_^

Quote:
Originally Posted by Savington View Post
So your argument is that because we cannot spend the money to fully optimize the intake manifold, we shouldn't bother at all? I've gotten a quote for the kind of engineering work you're talking about, and it goes way, way beyond plenum size and runner length. Throat angles, cross-sectional area at several points down the runner, portmatching, etc, etc. Just the design quote was more than I have into my current IM, and then they wanted like 2-3x that for sheetmetal fabrication. It might get me 60whp instead of 30, and it might get me 35. Someday when I **** gold I'll go have that done, but in the meantime I'll put my money into other places.
Exactly. Intake manifolds can get real expensive, real quick. Not only is proper design expensive but also the fabrication.

The honda skunk manifold is popular and therefore "gangbanged" because it is cheap and proven to be effective on a similar engine.
NickC is offline   Reply With Quote
Old 07-25-2010, 11:31 PM   #35
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,175
Total Cats: 2,578
Default

Quote:
Originally Posted by faeflora View Post
Is there anyone on the east coast with a hybrid honda mani? If so I will pay for some dyno tests. comeokn any takers
?
levnubin is in florida
18psi is offline   Reply With Quote
Old 07-25-2010, 11:42 PM   #36
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Quote:
Originally Posted by 18psi View Post
I get your point about no one REALLY doing thorough tests on stock im vs the sheetmetal ones, but then no one REALLY did any tests on the absurdflow and other tubular exhaust manifolds either to prove that they flow better than the BEGi log, yet everyone and their mother will agree that they flow more.
Ok this is the **** that bugs me. Just because everyone thinks a part is better doesn't mean that it is better part. What's missing is the quantification. That is the distinction between theory and practice right? And since we're spending our $ on it we should take the time to find out what the specific improvements are (if any).

I will paypal anyone who has a NB mani the $ for a back to back dyno on the hybrid and stock mani, with fueling adjust for the same AFR targets.
Faeflora is offline   Reply With Quote
Old 07-25-2010, 11:43 PM   #37
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Quote:
Originally Posted by 18psi View Post
I get your point about no one REALLY doing thorough tests on stock im vs the sheetmetal ones, but then no one REALLY did any tests on the absurdflow and other tubular exhaust manifolds either to prove that they flow better than the BEGi log, yet everyone and their mother will agree that they flow more.
Ok this is the **** that bugs me. Just because everyone thinks a part is better doesn't mean that it is better part. What's missing is the quantification. That is the distinction between theory and practice right? And since we're spending our $ on it we should take the time to find out what the specific improvements are (if any).

I will paypal anyone who has a NB mani the $ for a back to back dyno on the hybrid and stock mani, with fueling adjust for the same AFR targets
Faeflora is offline   Reply With Quote
Old 07-26-2010, 12:29 AM   #38
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 faeflora View Post
Ok this is the **** that bugs me. Just because everyone thinks a part is better doesn't mean that it is better part.
We aren't fools, we think the parts are better because people have seen specific results that show it. Trey picked up 800rpm of spool going from a BEGi cast manifold to his AF setup with no other changes. Same turbo, same catback exhaust, same intake manifold, same AFR targets. Sure, nobody bolted each one to a flowbench, but most of us don't have the resources to make those measurements.

Can you provide an example of a part that everyone assumes is better without any evidence at all?
Savington is offline   Reply With Quote
Old 07-26-2010, 01:53 AM   #39
Elite Member
iTrader: (12)
 
Join Date: May 2007
Location: Austin, TX
Posts: 1,923
Total Cats: 0
Default

Quote:
Originally Posted by faeflora View Post
I will paypal anyone who has a NB mani the $ for a back to back dyno on the hybrid and stock mani, with fueling adjust for the same AFR targets
How about some more details here. Are you looking for the only change to be just an intake manifold? If so, good luck because most people also change out the throttle body as well as alter the cold side intercooler piping. All of these items make a difference. Are you also willing to cover the entire dyno cost, not just the one money pull?
JayL is offline   Reply With Quote
Old 07-26-2010, 10:23 AM   #40
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Quote:
Originally Posted by JayL View Post
How about some more details here. Are you looking for the only change to be just an intake manifold? If so, good luck because most people also change out the throttle body as well as alter the cold side intercooler piping. All of these items make a difference. Are you also willing to cover the entire dyno cost, not just the one money pull?
stock vs modified Intake + TB + intake piping makes sense. I'd pay $100 for the comparison. That would be worth the r&d time to me. Preferably on a larger frame higher boost setup like yours.
Faeflora is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Turbo 1995 Miata Low mileage Clean Tekel Cars for sale/trade 29 02-05-2016 05:16 PM
Why dynos should plot Torque divided by MAP JasonC SBB ECUs and Tuning 11 10-27-2015 05:56 PM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM
1.8, C30-74 Rotrex, 9psi, 235WHP/190WTQ (E85) Lincoln Logs Dynos and timesheets 4 09-23-2015 01:26 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 09:16 AM.