Weak points of M96/97 Engines other than the IMSB
 

(I know this is 987 question, not 986, but you guys seem to know a lot about engines)

Ok, so I am 99% certain to be taking the plunge and investing in a boosted Cayman (deposit is down).

The motor was shipped to LN for machining and sleeving, 100mm pistons are forged JE 10:1, new crank with stock stroke so displacement is 3.7L, billet rods from LN, ARP bolts, all new bearings, IMS retrofit done, upgraded oil pump. TPC stage 2 intercooled turbo, Dynoed at 460 WHP/ 420 WTQ on conservative boost and tune, stock rev limiter.

Motor has 5k and two oil changes so far w/ used oil analysis looking good. Not tracked by current owner.

Planning to do AX/Track with this beast on dedicated sticky tires, keeping my Boxster S for when I take the girlfriend :cheers: (Probably still going to sell before end of summer)

So the big question is:

What are the failure points now? Do you think that this build addressed the weaknesses of this motor sufficiently?

I know that high-g oiling is an issue on M97s, so I may look into an Accusump or similar if I run anything stickier than Direzza ZIIs or RE-11s.

http://986forum.com/forums/uploads01...1392837140.jpg

Sounds like they used good parts in the engine. Hopefully thermal barrier coatings were applied to the piston tops at a minimum. IF the engine was properly built, heat management & oil quality will be your primary concerns.

And with increased cylinder pressure rod bearings and ion nitriding the crank are two things that are very worthwhile.

No one is complaining about the 10:0 compression ratio with forced induction? That only works under the best possible conditions, or with direct injection. Imagine what a tank of old fuel and a really hot day can do?

Of course the answer is " Its only running 5 psi".

Charge air temperature looks like an issue as well with that tiny water to air intercooler. Maybe with some meth injection it'll be under control.

Looks like a fun car though...

With all that torque, you may want to get rid of those POS stock transmission mounts, and all those flexy rubber bushings in the rear. Do you currently experience any wheel hop when launching hard?

Hmm, on closer inspection, it looks like those toe links are adjustable, so I am guessing you have proper rod ends on the toe links, so that should help.

I am not sure about whether the pistons are coated. Spoke to George at LN, and he said the 10:1 100mm pistons they sell are not, so I'll assume the ones in this car are not either. No idea about the crank being nitrided either, but the rod bearings were replaced.

I am going to look into a datalogging solution to keep an eye charge, oil, and water temps, as well as boost / AFR. I use a cobb on my MINI and it's been really helpful to get an idea of what's really happening.

I am going to consider methanol and possibly a motorsport oil cooler. I run meth on my MINI and I never have any heat soak issues, and I see about a 40 degree drop in AITs.

Thats exactly what I would do. Lower IATs as much as possible, and keep an eye on everything else. Keep the A/F ratio on the rich side, and leave the timing conservative. Looks like a bad ass car...

Longer duration camshafts will bleed some of that static CR away. Any time we boost, we add duration. The engine becomes much happier all around.

So do you offer upgraded camshafts? Id like to buy a set that didnt cost $4000

Only with our turn key engines. We don't sell any individual components.

Its my own designs, so the cylinder heads require manipulation, as well.

This car looks like it will be a handful on an AX course and is better suited for Daytona, Fontana or Homestead where it can stretch it's legs a bit. Even a highly experienced driver will have this car going backwards pretty easily.

I suspect a narrow tuning window so it's a good candidate for 100 octane instead of running the pump gas gauntlet. Excessive heat, cyl pressure, and detonation are the enemy.

Yep, I realize this car is a bit of overkill. I probably wouldn't buy it otherwise, but it's part of a trade-in-kind that winds up being very good for sales tax reasons. It will be a fun toy to have to play with for a season or two.

Enough jibber jabber...

Post pics when you have it :p:p

With all respect to your research and development, that sounds a lot more expensive.

Somedays, I feel like stuffing in a LSx engine in my car....

Makes you wonder why there's only 5-8 of these in existence. My guess is the stuffing part! ;)

Jeez Taylor, I will!

I got a super cheap enclosed truck quote -- $1340 for both the car and an extra set of wheels / tires for it. Probably going to have it picked up around March 10 -- Just in time to get good tires on it, a proper alignment, and couple autocrosses before first track day on March 29.

Now that's what I'm talking about!!

got the pickup scheduled for next week!

Yeehaw! I'm from tx after all.

Well. Any update?