What the **** is wrong with you? Isn't your username "spoolin2bars"? Did you know 2 bars is almost 30psi?

 

it's spoolin2bars is because of my galant vr4. and i wouldn't run that much at a trackday in it either. just seems like alot of abuse for not a big difference in lap times on most tracks. on the street or drag track, with sticky *** tires it makes sense. i would rather keep it safe/simple and run a trackday event, than be working on my car or spending money on replacement parts.

 

To each his own. I like having the power myself, and it is a lot of fun on the track too.
Fixing broken motors does suck though, but I am working on adding margin back. I suspect in this case the problem was caused by bad WI distribution into the #1 cylinder due to the manifold design. I am switching to port injection and better flow regulation.

 

i would love to have that much power too. but i can't sacrifice reliability for it. especially since i drive my car to all events still. hopefully i'll have a tow rig soon so i can push it harder. i think i will be running a little more boost for tws though. 11psi is 238whp so 12psi should get me to 250whp or so.
what about race gas? if your WI isn't flowing evenly throw some motorsport 104 or higher in there. then you don't have to count on the WI to save your motor. anyway's good luck with the new pistons. i'm dying to see what 300hp does out there.

 

Its ******* ridiculous. Reeling-in C6Z's, porsches, and just about anything under the sun is hilarious. When you make that kind of power, with decent suspension like Flex, and R-comps...there are no more excuses. FTD or tuck your tail.

 

I'm working on failsafe schemes, with some redundancy, for the WI in case it fails. But at the track, yeah using some higher octane fuel as a safeguard is probably a good idea.

I am also shopping for a cheap car trailer and when I get one will start towing with my truck to track events. That is what I do with the race bike now. It is nice knowing that no matter what happens, short of injury (a risk with motorcycle racing) that you can still get home. If I ever seriously got into car racing, I would build a track car. Ugly but fast, just like the race bike.

That being said, I would have driven home from MSR-C with no problems after running the motor HARD (at 14-20 psi) in several sessions with no problem had it not been for that piece of teflon tape. That was the root cause, not the track time. And I still got home even with a trashed turbo.

 

I know what you mean. On that track day I realized that my car isn't one you want to screw up in. With the new set-up I plan on running it at 10psi because I enjoy life. I need a cage for the way i drive out there.


I'm going to tune on 91-octane and run 93. Safety is win.

 

So, by chance are we ever going to see pics of these failed pistons...

 

FWIW my JE pistons are about 4.5mm from the valve pocket to the end of the piston. Will post pictures in a few min.

 

Dear Lord, are those plastic calipers? +/-.005?!?

 

yea they are crap, but its better than nothing. I'm not measuring oil clearances with them

 

What bore piston is that?

 

again, who tuned this car on the dyno? Did you use det-cans?

 

84mm

My car? Sav, yes det-cans were used and there was no knock. Rod failure.

 

Same thing happened to me with my stock motor.

 

Dropped the motor off at the machine shop this morning. I should have pictures of the pistons in about a week.

 

BTW, we just took apart a race motor with similar piston damage in a very short timeframe, and I took another look at the 11:1 "Spec Miata" piston on my desk. It's just how a piston gets hurt from detonation. The rod bearings on the race motor were also hammered badly, so you might want to check those out. And definitely get the car tuned.

 

Yep, agreed. I asked the engine builder to check out the motor including the bearings. Definitely going to get it tuned too, and am adding port injection on the WI, and some failsafes.

 

This is what happens when you think a motor has forged rods, so you tune to 17psi, and then find out it has stock rods.

 

OK, finally, the moment you have all been waiting for...
Click here for pictures of the damaged piston

A preview...


The machine shop finished reassembling the motor and I picked it up today, along with the old pistons. There are definitely signs of detonation. Check out that bent up chunklet that is barely hanging on, with the crack running through the cantilever end. I saw that in the borescope, and it was clear it was time to park it and pull the motor

The rod bearings were also damaged, specifically the top portion (where the rod presses the bearing into the crank during the power stroke). Everything else was OK, including the head. The rest of the pistons look fine, just some carbon buildup. Amazing how well it was still running despite this damage. No oil smoke, no noise, nothing. If I had not pulled the plugs out to regap them I would have never known, at least not until that chunk broke loose.

On a positive note, one of the head guys at the engine shop, Donald Duffin (Duffin Engine, one of three brothers that owns/runs the shop) had a great story about a trip he took to Barber Motorsports Park; I was out there last week. We were talking about how incredible the museum is (if you are in Alabama, you MUST go). He had a great story about getting to meet George Barber himself, and getting a tour from him of some of the otherwise restricted areas of the museum. Great stuff.

We need to have a Miata Challenge at Barber. A Miata would be a blast on that track, even better than Hallett.