Horton

Riiiiiiiiiiight so I've just finished my turbo build. I got the car back from mapping 4 days ago and have just been doing finishing touches fixing hoses down and stuff.

I finished all that this morning and actually just felt like it was finally finished. Me and my mate thought it would be a good idea to film a super slo mo of the launch control on my iphone 5. Yeah well the video turned out great but then a rod pushed itself through the side of the block #fail

The car was only making 158bhp and 181ftlb at the wheels at 13psi on a hub dyno. I have 195 tyres and a 4.65 ratio diff so the engine really should have been waaaaaaay safe. The bottom end was completely rebuilt using genuine Mazda parts at a vert good local engine builders and had only done around 3000 miles since that rebuild. It ran smooth as silk with no knocks or taps. No smoke either. All seemed literally perfect.

I have a spare engine already but I'd like to know why has this happened.

I was actually watching the boost gauge when it blew up and it was just under 1 bar so it wasn't over boosting. Maybe it couldn't handle the launch control?

I imagined the diff or gearbox might go soon but not this. I'd like to try to figure it out so it doesn't immediately happen to my spare engine.

Anyone have any idea why this might of happened?

Here's the video

18psi

iTrader: (76)

knock/det causes a spike in cyl pressure enough to bend/break rods and anything else.

doesn't help at all that you were abusing it like a redheaded stepchild. (if you think anything about that launch was "safe" for the engine, you got another thing coming)...spitting flames out the tailpipe means you had all sort of unburnt fuel in the engine/exhaust/etc

Horton

Yeah I realise the using the launch control isn't exactly being nice to it.

It's mapped on ms2 and that's the launch control function. I have literally no idea what it does to make boost and flames as I drop it off to be mapped.

It blew after I changed into 2nd if that makes any difference? I was thinking the launch control could damage the gear box / diff but not really do the engine any harm. I mean I'm aware it wouldn't do it any good but I also wasn't expecting it to blow up with its first use.

18psi

iTrader: (76)

cutting spark and/or fuel will absolutely put a ton of stress on the engine.

yours happened to not like it more than others.

I'm not blaming you, I'm just saying that when abused, even a low hp setup can blow up. And we don't even know what condition your engine was in and how safe the tune was (protip: just because it makes low power, does NOT automatically mean its safe).

Horton

Hmmm right well thanks for the input. Hopefully I can figure out what happened before I put my spare engine in.

ThePass

iTrader: (3)

Mechanical empathy woulda helped.

Ultimately though, I'd say it needed a better tune. When you say 'mapped' you mean you paid someone to tune it I'm assuming?

-Ryan

triple88a

iTrader: (2)

Hmm so much psi with so little power. You running a 1.6 with way too much timing or something?

Horton

Nope it was perfectly healthy 1.8 as far as I knew.

And yeah it was professionally mapped. I don't get involved with that at all. I didn't even drive it after I fitted the turbo. I picked my mapper up in my van and he drove it back to his with a base tune in it so he could get it there safely.

Fair enough with the people saying I should have been mechanically kinder to it but what's the point of having launch control if you can't use it? That's literally the first time I'd used it since the turbo was fitted.

triple88a

iTrader: (2)

Perhaps base timing was off? Did your tuner check it with a timing light?

Horton

Yes I seem to remember him doing that before he left mine.

I've taken the turbo off this morning and that seems fine. All the plugs look good so i don't think the piston has hit the head. It's no:4 that's gone there's a nice size hole next to my turbo oil feel line.

Once the engine is out I'll take a good look at the rod and see if I can see anything obvious.

Anything I should look out for?

sixshooter

iTrader: (12)

Launch control exists in Megasquirts because ricer kids who abuse their cars asked for it. It doesn't make it smart to use, as you may have noticed. It was originally designed for highly built competitive drag cars using wrinkle wall racing slicks and oversized turbos. Is that you?

Since you have supplied no details regarding your turbo, tune, or plumbing configuration, I don't know whether your tune was garbage or not. A tiny turbo and log manifold with a very restrictive exhaust system could conceivably make that little power at 13psi, but it sounds like a tuning problem. Details on exhaust system? Log manifold? Catalytic converter? Piping diameter?

After listing all of the details of your modifications, take a screenshot of the spark table and post it here so that we can evaluate it for you. We'll see if we can help.

sixshooter

iTrader: (12)

If you want to shoot flames without destroying your engine and related hardware, just buy an automotive flamethrower kit. AutoLoc® FLAME2 - Exhaust Flame Thrower Kit (Dual)

Horton

My setup is a log manifold to 2.25 down pipe and straight through exhaust with no cat. So yeah could be why power was down I suppose. Not sure on the exact turbo. It's a t25 but I'm not entirely sure which one. I know that apparently I need a gt2560 to make more power so I assume mine is the one below that.

Can't post my spark table as I said earlier I don't touch the mapping at all. Don't even have a lap top to plug into it.

With regards to the launch control, if my mapper says it's ok who am I to argue? As I said I don't touch the mapping and had no warning that the launch control would blow the engine in its first use. Also there are plenty if videos on YouTube of other turbo mx5s using launch control and not exploding so why would I assume that it's going to blow mine up?

Braineack

iTrader: (62)

im going with: you suck at tuning. you have no idea what you're doing. you abused it. you were asking for it to happen.

kicker guess: you're still running 87 equivalent octane.

pointing out retardation: you rebuilt a turbo motor using mazda parts that are known to fail with any abuse.

Horton

Did you even read any if this?

I didn't tune it. My mapper (a well known good mapper who I will not name as I don't believe it's his fault) was picked up by me and driven to my garage to start the car and drive it back to his safely where it could be tuned in the hub dyno.

I didn't build a turbo mx5 to not abuse it. It's clearly a toy and judging by the whole internetz they can take turbo power and abuse easily so long as it's done right (proper ecu, good cooling, oil cooler, ect, ect). My car was done right. Not a mega budget build but nothing was skimped on either. Mazda rods are not known to break at 181ftlb at all and it was mapped what I thought was safe.

Also running 99 octane super unleaded here in the uk.

Pointing out retardation: you should have read the thread mate.

Horton

Anyway back to some sort of constructive chat....

So no one else is using launch control on their turbo mx5s with standard bottom ends?

If it's as simple as that then happy days obviously I'll get launch control disabled with he spare engine.

hornetball

iTrader: (4)

Quote of the century after blowing up an engine on it's first go:



BTW, I've seen this happen a couple of times to people that completely relied on 3rd parties for MS dyno tunes. In both cases, there were two things in common:

1. Power was extremely low despite healthy boost. In the other case, a 1.6 making 135RWHP, in your case a 1.8 making 158RWHP.
2. Lifespan was short. In the other case, all four pistons pulverized by detonation on its first track session. In your case, well, you know.

What do we learn from this?
1. Det does not make power.
2. Det destroys engines.
3. Det is nearly impossible to hear on Mazda B engines. You need to be using det cans. I hardly ever see 3rd party tuners doing this.

Horton

So I should have had my car mapped at well known good mapper, then when he tells me it's all good I should have stood there and said no it isn't. Even though I have no idea about mapping. If I did I would have done it myself. But I don't so I took it to someone who is known to be good. As far as I'm concerned I did everything right?

If it does turn out to be a bad tune I will be very disappointed but I'm giving him the benefit of the doubt as I think he's a good guy.

Also he said he does use det cans. So hopefully it's not that.

hornetball

iTrader: (4)

Nobody said he's a bad guy, but we're not impressed by the tune. The objective evidence is hard to ignore.

Do your teardown and report back with some real information instead of emotion. We'll go from there.

curly

iTrader: (25)

So sad. I've track on N/A car on a base map tune, and my turbo car multiple times. Zero rod lossage.

Did you set base timing before giving it to him?