Miata Turbo Forum - Boost cars, acquire cats.

Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   DIY Turbo Discussion (https://www.miataturbo.net/diy-turbo-discussion-14/)
-   -   Is my buddy being dumb? (https://www.miataturbo.net/diy-turbo-discussion-14/my-buddy-being-dumb-44122/)

turotufas 02-21-2010 12:55 AM

Dat whoo whooooooooo!

ZX-Tex 02-21-2010 12:58 AM

Long Live Bubb Rubb! Whoo whooo!!

You can run a FPR on a 99 but you have to run a return line. As mentioned real fuel management is a much better, more powerful solution and really does not cost much more. Maybe you can find a good used FPR really cheap.

Keep in mind your buddy is going to be very, very tempted to turn up the boost, and that setup has no overhead (negative overhead) so he could be in for problems.

But, if he HAS to keep it cheap, maybe a good dose of water-meth in boost would limp it through the inevitable lean spots. But even if that would work, just like with the FPR, the money would still be better spent on a MS.

b14 se-rious 02-21-2010 02:56 AM

Running 5psi isn't enough to go so lean that you will detonate.

elesjuan 02-21-2010 03:25 AM


Originally Posted by b14 se-rious (Post 526069)
Running 5psi isn't enough to go so lean that you will detonate.

Where do you people come from? Just here to sell something?

An engine with 0psi can run lean and / or detonate... Thats like saying "Oh, my rotary won't shit the apex seals out the exhaust ports running high boost and water for fuel.."

Take my personal experience, 5psi IS MORE than enough to cause an engine to detonate WITH proper AFR.

18psi 02-21-2010 03:33 AM


Originally Posted by b14 se-rious (Post 526069)
Running 5psi isn't enough to go so lean that you will detonate.

end yourself now:facepalm:

b14 se-rious 02-21-2010 04:04 AM

Sorry, but from my experience 5psi isnt enough to detonate. Ive been around more than a few turbo miatas and never had an issue. They were not my personal cars, friends cars but I of course wouldnt personally advise running boost without some sort of fuel management, but from experience, 5 psi has done anything. And no, I am not here just to sell something.

elesjuan 02-21-2010 05:04 AM


Originally Posted by b14 se-rious (Post 526088)
Sorry, but from my experience 5psi isnt enough to detonate. Ive been around more than a few turbo miatas and never had an issue. They were not my personal cars, friends cars but I of course wouldnt personally advise running boost without some sort of fuel management, but from experience, 5 psi has done anything. And no, I am not here just to sell something.

I'm sorry to break this to you but your experience with automotive theory is obviously incorrect, inconclusive, or non-existent.


Knocking (also called knock, detonation, spark knock or pinging) in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front. The fuel-air charge is meant to be ignited by the spark plug only, and at a precise time in the piston's stroke cycle. The peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive. It should not be confused with pre-ignition (or preignition), as they are two separate events.
Manifold pressure is irrelevant to the existence of Knock, Detonation, pinging, preignition, or whatever you want to label it. Here let me show you:
http://www.jugrnot.com/IMG_6175.jpg

Thats MY piston, from an engine I built for an old pickup. 11:1 compression, big ass roller cam, heavily modified head, good intake and exhaust system, took a motor with a factory 5500rpm redline and spun it to 7000 on a regular basis. Notice I say nothing about boost? See something wrong with it? How about the crack from the face to the skirt? Maybe the large portion of material missing from the ring land at the top ring? Notice the piece of piston ring impaled into the face of the piston?

The engine that piston came out was very well tuned and ran like a top. One screamin' ass truck, until I got some bad gas. Guess what? Detonation under hard acceleration, without the presence of boost. Fucked up the block, a piston, and the cylinder head. What happened? It probably went lean and had too much spark advance.

I also share experience from another board member who had a supercharger installed on his vehicle for a while, which is now installed on mine. With supporting bandaids, 10:1 AFR, and 5psi guess what happened? It killed his motor. How? Detonation.

Here, I'll link you to a thread I started on here a couple years ago, asking about why his oil pressure gauge would freak out on the highway. It did it from day one of installing the supercharger with the 5psi pulley, and even worse with an 8psi pulley.

https://www.miataturbo.net/forum/t16318/

Not here just to sell stuff, yet you have 25 posts on this board and already posted up a for sale thread? :rly:

FastColt 02-21-2010 08:58 AM


Originally Posted by b14 se-rious (Post 526088)
Sorry, but from my experience 5psi isnt enough to detonate. Ive been around more than a few turbo miatas and never had an issue. They were not my personal cars, friends cars but I of course wouldnt personally advise running boost without some sort of fuel management, but from experience, 5 psi has done anything. And no, I am not here just to sell something.

This is 100% true. Every turbo car has some sort of device on it to control the timing or fuel mixture under boost. A normally aspirated car will only pruduce enough fuel for vacume to reach zero, once you start going into boost, the car still assumes your vacume is at zero, when in reality your at 5psi and needing more fuel to compensate for the 8 trillion times more air running through your engine. (not really 8 trillion, just trying to prove a point)

Here's what i see happening, your friends car will run like shit for about a week, then start smoking really badly, then the motor will die completely, then he'll register to this forum where he will then receive a severe lashing for asking a dumb question while not using the search tab, at this point 18psi or Hustler (one of the two) will then make fun of your friend so badly, that he will likely cry for a week straight, at which point he will decide to part his car out on our parts for sale section, and we will reap all the benefits! SO...........do it right.... thanks!

00mx5se 02-21-2010 09:14 AM

1) him and his brother are part ricers. 2) he's getting kinda annoyed with me for trying to get him to look into management. 3) (because i know he won't look) I get first dibs on parts. hardtop, exhaust manifold and turbo are mine...

ZX-Tex 02-21-2010 09:42 AM

If he is going to be stubborn and do something stupid, let him do it, then buy his stuff when he parts it. The '99 has a good head so you will want that too if he does not melt it. If he has a 6-speed and/or a torsen jump on those too. He is going to blow the welds on the block so it will be trash :giggle:

Please report back in later on, let us know what happens.

gompers 02-21-2010 10:12 AM

I ran my miata unmanaged for 2 years, 55,000 miles ;p

Shes still kickin. Smoke is starting to appear now, tho lol


I wonder if theres a connection there?

sn95 02-21-2010 10:16 AM

Ring lands or rods
 
Ok, you guys are all having way too much fun with OPs hard headed buddy. So, I'd like some opinions on how this motor is going to let go. Assuming the boost is kept in the 5-8psi range (with no bandaids), will the top ring lands on the stock pistons let go first (at the edges near the intake valve relief) or do we get the big bang with a stock rod exiting the side of the block???

magnamx-5 02-21-2010 10:35 AM

HE will eat a piston if he continues on this raod, and if nothing else he could bend a rod depending on how stuborn he is.

ZX-Tex 02-21-2010 10:48 AM

He will be running a lean charge with more energy and initial heat, resulting in hot components, increased detonation risk, and all the risk for the usual resulting damage. Rings, pistons, valves, chambers, and definitely blown welds from the F&F effect.

What do you mean by 1/2 a bandaid? Based on the OPs description his buddy is talking about running no bandaid.

kotomile 02-21-2010 10:55 AM


Originally Posted by gompers (Post 526133)
I ran my miata unmanaged for 2 years, 55,000 miles ;p

According to your sig, you have an FMU and larger injectors. You're a lot better off than the OP's buddy.

sn95 02-21-2010 12:38 PM


Originally Posted by ZX-Tex (Post 526144)
He will be running a lean charge with more energy and initial heat, resulting in hot components, increased detonation risk, and all the risk for the usual resulting damage. Rings, pistons, valves, chambers, and definitely blown welds from the F&F effect.

What do you mean by 1/2 a bandaid? Based on the OPs description his buddy is talking about running no bandaid.

Oops, edited original post to show no bandaids. I'm not looking for a generic "hot lean, increased detonation answer", that's readily apparent. My guess is specifically that this engine will suffer top piston ring land failure right below where the valve relief(s) for the intake valve(s) come closest to the outer edge of the top of the piston. I'm speculating (and this is just a SWAG) that OP's buddy isn't going to get severe enough detonation at 5-8psi to bend a rod/put a rod thru the side of block. I'm interested in everyone else's opinion on whether the engine can be beat on hard enough at 5-8psi to bend a rod/put a rod thru the block. Sick humor, but entertaining nonetheless :laugh:

Tw34k 02-21-2010 02:10 PM


Originally Posted by b14 se-rious (Post 526069)
Running 5psi isn't enough to go so lean that you will detonate.

cool well then ill just slap a nice gt40r on my car and as long as i stay @ 5 psi ill be gravy right..:crx:

Posts like this one ruin the internet.

00mx5se 02-21-2010 03:55 PM

I'm OP lol

He drives HARD, his last car was a grand am se or gt one of those with 155k on it died three weeks ago, when he got it the car ran fine. one too many burnouts.

KPLAFIN 02-21-2010 04:17 PM


Originally Posted by 00mx5se (Post 526247)
I'm OP lol

He drives HARD, his last car was a grand am se or gt one of those with 155k on it died three weeks ago, when he got it the car ran fine. one too many Neutral-drops.

Fixed?

TimR 02-21-2010 04:20 PM

:idea: Go to autozone buy a whistling intake... Buy an exhaust that has a fake bov in it. Shit dude wait! Dont forget the street glows :laugh:

Let your friend be the ricer he is... tell him not to bitch to you when his car blows up.


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