More boost safely - 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 09-03-2011, 11:38 PM   #21
Senior Member
Thread Starter
iTrader: (5)
 
Join Date: May 2011
Location: London,OH
Posts: 1,125
Total Cats: 13
Default

btw its not like i held it at 12 psi for a long period of time. i let off as it was hitting 12. so maybe 5seconds of 12psi no knocking, no odd nosies. sounded like normal.
redturbomiata is offline   Reply With Quote
Old 09-04-2011, 12:24 AM   #22
Elite Member
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,133
Total Cats: 599
Default

How many times does a motor spin per second at whatever rpm you were at? Now multiply by 2 as thats how many combustion cycles happen per revolution on a 4 banger.
Thats how many lean combustion cycles you ran in those 5 seconds. Heat doesnt have to knock to melt ****.

You might want to start by reading the stickies.
triple88a is offline   Reply With Quote
Old 09-04-2011, 03:00 AM   #23
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,371
Total Cats: 1,332
Default

I would support a rule that banned members who use arbitrary boost figures as the "limit" for anything inside the motor.

Boost is an arbitrary measurement of intake restriction. I guarantee that 12psi from a GT47-88R will grenade the **** out of a BP so fast your head will spin, but a GT1248 making 12psi would be barely noticeable.

Boost is literally the most retarded way to measure the strength of a motor. It's only slightly better than horsepower ratings. Engines are rated for torque, and more specifically combustion pressure. If you had some crazy turbo setup that made 500wtq at 2500rpm, but only made 190whp, and did it all at 10psi, would the "motor holdz 15psi bro" crew say that a stock BP would hold up to that abuse?


The motor won't hold up to 15psi, or 20psi, or 2psi, or 7289375843q2098q7209834psi. It will hold up to approximately 230-250wtq, depending on your tune and usage. Or you'll melt the everliving **** out of the pistons running 90whp on the track, if you don't have a wideband and you're running 14:1 at WOT.
Savington is offline   Reply With Quote
Old 09-04-2011, 03:04 AM   #24
Senior Member
iTrader: (1)
 
Join Date: Oct 2008
Location: Trailer County
Posts: 530
Total Cats: -9
Default

Like others say, crank it up to 20 psi, there is no limit!

Like stated, buy a compression and vacuum tester. Check your sparkplugs...

What is the gap in the ones u have?

Buy NGK7 or NGK8, those platinum +4 r junk.

What r the settings in ignition timing?

It is good to at least do the compression test to have a default number to work from, the same goes for vacuum. Install a oil pressure gauge, what r the readings at idle?

"slightly better fuel pump"???

You are lucky that engine is still running... dont raise boost.

Yeah, that was a good wideband, make sure the sensor is included when buying on EBAY. Have the grounds as much as possible to the engine block, do not install the sensor close like a O2 sensor, give it like I said, like 2-3 feet from the turbo (exhaust side).

Can you post exhaust size, 2.0/ 2.5/3.0?

Intercooler? piping size?

The motor won't hold up to 15psi, or 20psi, or 2psi, or 7289375843q2098q7209834psi. It will hold up to approximately 230-250wtq, depending on your tune and usage.
posted by Savington...


Of course!

But basing it on where he is at, and where he wants to go, he must take care of several details before continuing to increase boost.
mazpr is offline   Reply With Quote
Old 09-04-2011, 03:26 AM   #25
Elite Member
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,133
Total Cats: 599
Default

Quote:
Originally Posted by Savington View Post
I guarantee that 12psi from a GT47-88R will grenade the **** out of a BP so fast your head will spin, but a GT1248 making 12psi would be barely noticeable.
See this is what bothers me. I've accepted it because its said however still doesn't exactly makes full sense to me. If you have steady 12 psi then when the pistons open up they will fill up with 12 psi, no more no matter how much that turbo flows as even if that turbo flows 50 gallons a second it cannot get above the 12 psi road block. What makes sense to me is each piston can only be filled 100% with 12psi. For more the pressure would have to be more than 12psi. If the gt1248 fills the piston up to 100% of the 12psi and the gt47 does that also how would it blow the motor up (assuming the wastegate or boost creep is no issue)
triple88a is offline   Reply With Quote
Old 09-04-2011, 03:39 AM   #26
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,371
Total Cats: 1,332
Default

In order:
-Increase size of turbo
-Increase size of turbine housing
-Decrease backpressure
-Lower backpressure means that the pressure differential across the exhaust valve is higher during the exhaust stroke, which means...
-once the intake valves open, the chamber pressure is lower, and therefore the pressure differential across the intake valves is higher, which means...
-the larger turbo will more efficiently move air through the system at the same boost level

More air = more power

More power = more broken ****.


The ultimate example of this is with a supercharger. Superchargers produce boost keyed off the crank, so let's say there's a Honda with a Rotex that makes 12psi at redline and about 275whp. The owner decides to put a camshaft in that typically makes another 30whp. He installs the camshaft, boost levels DROP to 7psi, and the car makes 350whp. Did the flow go down? No, it went up dramatically - the camshaft reduced the pressure in the intake manifold drastically, but the power went up anyway.

Less boost, more power, more broken ****.


Boost is only good for comparing the SAME turbo at Xpsi vs Ypsi. It has a convenient correlation to flow, as long as everything else stays the god damn same. Once you change the turbo all bets are off.
Savington is offline   Reply With Quote
Old 09-04-2011, 04:43 AM   #27
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,202
Total Cats: 2,584
Default

Quote:
Originally Posted by mazpr View Post
18 psi, each setup is completely different, but looking to what he has I would not go any further on boost. All following posts to yours state the same freakin genius.

Have you ever installed a bandaid? Have you ever used one? So shut the **** up as you dont know shyt what they can do...
Yes I have fucktard. Never on my own cars though cause I'm not a ******* moron like you. Then later the owners of said cars came back to me because either they were tired of the **** poor power they were making or because they broke **** and/or needed to diagnose a bunch of issues. Eventually everyone goes with a proper setup. The dumb *** ones just take longer to realize the truth. Hell, you're still in denial.

HOW MUCH BOOST YOU RUNNING BRO? OH **** 12? WELL THE LIMIT IS 13 SO YOU SHOULD BE GOOD


DERP
18psi is offline   Reply With Quote
Old 09-04-2011, 05:02 AM   #28
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,110
Total Cats: 518
Default

**** are you serious? I'm at 14?!!!!!!!!1!1?1?1!?!??1!! **** **** **** ****....


Brb...gotta turn down the boosts to 12....

Lots of misinformation in this thread, and I'm sorry mazpr, but your MegaSquirt thread doesn't help your credibility. Your enthusiasm is very welcome, however please realize we've all been corrected by a more knowledgeable person before. It's how we learn, don't take it personally, no matter how harshly they point it out.

The bending rods is a little off topic, 12 psi is well within 250 - or even 200rwtq - and is plenty safe as long as he has a good tune, which was his original question.
curly is offline   Reply With Quote
Old 09-04-2011, 12:52 PM   #29
Senior Member
Thread Starter
iTrader: (5)
 
Join Date: May 2011
Location: London,OH
Posts: 1,125
Total Cats: 13
Default

2.5 on the exhaust, and 2.5 on the intercooler piping. its a little leaky at the moment. my best friends dad is also my mechanic and has the stuff to do compression test, he has the time to do it tomorrow. quick other question dosnt the MS have a wideband built into it.
redturbomiata is offline   Reply With Quote
Old 09-04-2011, 03:02 PM   #30
I'm a terrible person
iTrader: (19)
 
FRT_Fun's Avatar
 
Join Date: Apr 2009
Location: Arizona
Posts: 7,293
Total Cats: 180
Default

Kind of... You need the actual wide band sensor. From there you could wire it up to the MS and see your A/F ratio on the laptop in tunerstudio. But no one keeps the laptop up and displayed 100% of the time, so it's best just to get a gauge. An AEM one can with sensor can be found for $120.
FRT_Fun is offline   Reply With Quote
Old 09-04-2011, 03:38 PM   #31
Elite Member
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,133
Total Cats: 599
Default

Thanks for the detailed explanation Savington. So basically it all comes down to filling that cylinder up to 100% of whatever boost your running.

Smaller turbo would fill it up to only 80 so 80% of 12 is more like 9.6psi actually making it to the piston while a bigger would go to 90 and so forth...
triple88a is offline   Reply With Quote
Old 09-04-2011, 04:20 PM   #32
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,371
Total Cats: 1,332
Default

That's not a good way to think about it. You don't fill a glass of water with 14.7psi of water - you fill it with 8 ounces of water, and the pressure inside is 14.7psi. If you have flowbench numbers from the cams at various lifts, and you know the duration of the cam, and there's 12psi of pressure on the backside and you assume some pressure in the cylinder, you can sit down and figure out how much air will flow through them at a given RPM.

You don't fill containers with pressure - you fill them with volume, and they exert pressure.
Savington is offline   Reply With Quote
Old 09-04-2011, 04:24 PM   #33
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,371
Total Cats: 1,332
Default

Quote:
Originally Posted by FRT_Fun View Post
Kind of...
No, not even kind of. That's like saying the Megasquirt kind of has a cam angle sensor on board, since it can read the signals that are given to it from a cam angle sensor.

The MS will DISPLAY the readings that you feed it from a wideband CONTROLLER. The controller gets its readings from the sensor. The controller is the big black lump in the LC-1 kit, or it's built into the gauge in the AEM UEGO kits.

I don't care if your fuel regulation is a pair of vise grips on the return line and you manually squeeze them every time you go into boost - if you don't have a wideband, you are playing Russian roulette every time you put your foot down.
Savington is offline   Reply With Quote
Old 09-04-2011, 04:30 PM   #34
I'm a terrible person
iTrader: (19)
 
FRT_Fun's Avatar
 
Join Date: Apr 2009
Location: Arizona
Posts: 7,293
Total Cats: 180
Default

I was thinking more along the lines of the AEM inline controller, but figured they would be cheaper than just going with a guage. So yea, kind of, you can display your A/F in TS with a MS, but it won't do it alone.

Sometimes, you have to infer what is being asked. Somehow I doubt that he actually thinks that the MS has a wideband sensor inside, unless he also thinks you mount the MS in the exhaust. Which at that point, I give up.
FRT_Fun is offline   Reply With Quote
Old 09-04-2011, 04:45 PM   #35
Elite Member
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,133
Total Cats: 599
Default

Quote:
Originally Posted by Savington View Post
I don't care if your fuel regulation is a pair of vise grips on the return line and you manually squeeze them every time you go into boost.

You guys rock

Thats definitely sig worthy.
triple88a is offline   Reply With Quote
Old 09-04-2011, 05:58 PM   #36
Senior Member
iTrader: (1)
 
Join Date: Oct 2009
Posts: 1,436
Total Cats: 58
Default

Quote:
Originally Posted by mazpr View Post
18 psi, each setup is completely different, but looking to what he has I would not go any further on boost. All following posts to yours state the same freakin genius.

Have you ever installed a bandaid? Have you ever used one? So shut the **** up as you dont know shyt what they can do...

I bent 3 rods, the pistons are fine, is it tuning...

Kaboshe, I dont want to start a ping pong game and hijack the thread, whatever lucky you....
I loled.
Enginerd is offline   Reply With Quote
Old 09-04-2011, 11:23 PM   #37
Senior Member
Thread Starter
iTrader: (5)
 
Join Date: May 2011
Location: London,OH
Posts: 1,125
Total Cats: 13
Default

Quote:
Originally Posted by FRT_Fun View Post
I was thinking more along the lines of the AEM inline controller, but figured they would be cheaper than just going with a guage. So yea, kind of, you can display your A/F in TS with a MS, but it won't do it alone.

Sometimes, you have to infer what is being asked. Somehow I doubt that he actually thinks that the MS has a wideband sensor inside, unless he also thinks you mount the MS in the exhaust. Which at that point, I give up.
let me rephrase i ment as an add in, or displaying from the o2 that is already on the car. i was thinking about buying the unassembled kits there allittle bit cheaper what all is needed besides the kit.
redturbomiata is offline   Reply With Quote
Old 09-05-2011, 05:55 AM   #38
Elite Member
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,133
Total Cats: 599
Default

triple88a is offline   Reply With Quote
Old 09-05-2011, 03:20 PM   #39
Senior Member
Thread Starter
iTrader: (5)
 
Join Date: May 2011
Location: London,OH
Posts: 1,125
Total Cats: 13
Default


Cyl 1

Cyl 4
They look good to me.
Attached Thumbnails
More boost safely-imag0140.jpg   More boost safely-imag0141.jpg  
redturbomiata is offline   Reply With Quote
Old 09-05-2011, 03:27 PM   #40
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,371
Total Cats: 1,332
Default

Are you really posting pictures of your spark plugs to convince us that your tune is good and you don't need a wideband?
Savington is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 12-15-2017 09:00 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
LucaCarMods's Boosted Dutch Miata Build! LucaCarMods Build Threads 11 02-14-2016 07:13 AM
Going back to stock. Need some 1.6 parts. Trent WTB 2 10-01-2015 01:15 PM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 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 09:46 PM.