Is my buddy being dumb?
 

My friend Wilbert got his 99 Mx-5 this morning and he's going out later today to pick up the turbo. He plans to run it on 5psi. when I told him about what you guys said about MSPNP he told me his dad said he wouldn't need it because it's running such low boost... He's a really close friend and I don't want to see his car go up in smoke, should I try and stop him or will his car be ok? I do trust his dads judgement he's good with engines (helped me build my turbo sc2).

Pretty much all engines from the factory can handle up to 8psi but its the fuel management. Your buddy should at least have a fpr.

fuel pressure regulator?

Yarp. Just ask your friend to join up here so he can learn the error of his ways.

I take it your name is Wilbert?

https://www.miataturbo.net/forum/t44045/
Nice, he has the same boost goal as you.


I'm just calling it as I see it. Read the stickies.

You had a turbo saturn and you don't know what a FPR is?

"You had a turbo saturn and you don't know what a FPR is?" just making sure, I don't remember all the acronyms. and yes he has somewhat of the same goal. I know what your implying and no I'm not asking for me and yes I'm reading the stickys. it's to late anyway hes already started installing.

and my name is Chris...

A '99 has a returnless fuel system so an AFPR would not be in the cards. At that low boost level, try looking into larger injectors, control for them, and timing retard.

to notice any apreciable horsepower he will need a way to manage shit botom line.

If he just wants a turbo for shits and giggles and to say that his car is turbo-ed then go for it, just slap that shit on there and go. If he wants to maintain a reliable car and have it last for years to come, fork over some cash on a legit management.

Learn something new errday.

I really don't think it's going to last long, first thing he does is hops in the car and revs it up to set off the bov...

It won't last long. He needs some sort of fuel management. He could get away with a FM voodoo box at that low boost level with stock injectors but for the money he should atleast go with a DIYPNP. It will allow him to have full control of fuel, ignition timing, electronic boost control, knock detection, launch control and many other things.

Or... he can just learn the hard way.

"starts the car and revs to hear bov"....:facepalm: No hope for this one.

His dad may be somewhat educated but that wont stop his (sounds to be ricer) son from making some dumb ass choices.

Yes you can get away with low boost apps if you are aware and smart about it, but its ALOT more dangerous.

The miata has no way of sensing boost so it doesn't know that it should be adding more fuel. On the early cars a AFPR was used to add more fuel, on the later cars you either run a piggy back system that "tricks" the ECU into adding more fuel, or you run a proper engine management system and control everything the right way.

Make sure he's running 93.

Jesus dude, show him this thread at least. This is a bunch of people experienced with turbo Miatas saying exactly what he must do to save his engine and make power (which is the entire point of turbocharging, right?).

I bet the engine was cold when he was revving to hear the BOV too, yikes. Anyone out there need a rebuildable NB engine?

Explosions are fun.

where are you located? I'd love to get a 99 shell......


trade plus cash for my already turbo NA? lol

Problem solved, way cheaper.

Dat whoo whooooooooo!

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.

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.

end yourself now:facepalm:

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.

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:

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!

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...

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.

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?

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???

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.

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.

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

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:

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.

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.

Fixed?

: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.

Please send carnage pics.

Every time something dumb comes spewing from his mouth just cut him off mid sentence and scream STFU RICER BOY!

Holy exploding thread Batman.

Seriously, this whole thread can be sumed up as follows:

Can we just run insanely low boost without any big fueling mods. This guys says so.
No. See Stickies.
I bet it would work.
You cant run any boost without something!!!!!!!!!!!!!!!!!!!!!!!!! Die!!!!!!!!!!!!!!!!!
OK OK.
Die!!!!!!!!!!!!!!!!!!!!!! *&^(*&%^%$%#$%#!!!!!!!!!!!!!!!!!!!

And a few people in here attempting to punch above their weight when it comes to 'what will happen'. I do this too so I hardly look down on it, I just want to point it out.

On a mass-air based management system, you dont 'only get enough fual for 0 vacume'.

You get fuel based on the airflow as read by the MAF/AFM sensor which could care less what pressure is between the turbo and intake manifold. The additional flow through the AFM causes the ECU to try to deliver more fuel.

So while it is a horrendously bad idea to just run 5 psig with no fueling mods, the car will attempt to maintain the proper AFRs assuming it is an AFM equiped vehicle.

Frankly if the fuel pressure was set higher and a bigger pump put in such that the car simply ran rich in WOT situations and the base timing was set way down, it would likely survive a long time. It would have crap power and be a joke compared to what it would be with decent management. But it would likely be OK.

Except you neglect to figure something about the miata ECU into your theory that it refuses to enrich the fuel mixture significantly below 4000rpm. If the OP's friend wants to run a 5psi turbo on his car with a budget build bandaids are available and would work well enough to maybe keep the car alive for a few months...

seriously interested in the shell when the motor pops and he doesn't wanna fix it...

lawl and the bidding begins. How about a life expectancy raffle $2 buy in and the winner gets a tial w/g keychain or something.

OK, then I am confused. What AFR will it try to hold under WOT below 4K in totaly stock form?

__

hahah I'm showing him this tomorrow when I'm up there

I KNOW he will understand this, see, fellow members, it is all about becoming more user friendly, and accommodating to today's younger generations use of the media for a gain of knowledge about a particular subject matter.




Attachment 200132

It looked to be about stoich when i had the wideband on my car before the megasquirt went on, im sure someone knows the furrealz answer to that though. Thats why on the stock computer i always felt a huge jolt of power right there.. VTEC mmmmmmmmmmmmmmmBAAAAAAAAAAAAAAAH!

Stock form is irrelevant. Its when you add that mythical 5psi of boost and the ecu won't let you add fuel below 4k..

http://www.jugrnot.com/dyno.jpg

I'll be honest here, I'm not an expert at tuning and I'm learning a lot as I go myself, I can just speak on a few things I know for certain and what I've learned. That dyno chart is from a 94 w/RRFPR along with a 5psi JRSC. Notice the AFR is lean as shit in boost below 4500rpm? As I understand the factory ECU won't add more fuel below that, which is why someone came up with the o2 clamp idea.

The point is adding positive manifold pressure to a factory stock naturally aspirated miata without any additional supporting mods won't last. Period.

Yeah man, you'll blow your welds. Glad to see i was right-ish about the afr down low.

OK, I got it now.

Yeah, stoich at 5 psig with little to no IC just *might* be a problem. Yikes.

I need to get that legendary software.. Nos_program_2.0

How else am i supposed to know when i have a danger to manifold situation?

Altho if it did in fact warn me of such occasions i would most likely scream shut up and slam the lid to my laptop.

Its a little known fact that the slamming of the laptop is what caused part of the floor pan to come out.

Real racers know that when you blow the welds on your intake your blinker fluid catches fire and you loose the quarter panels.