Stressed R6 Engine?

[dartmouth01]

Hey all,

Any of you who are running or have run R6 engines fully stress your engine in the frame? If you have, what tradeoffs has it been in terms of rigidity and stiffness? Also, it seems that many teams running CBR engines fully stress theirs, am I wrong in this assumption?

Thanks in advance!

Al

[Lash]

Al,

We have a CBR engine and want to have it fully stressed. We are concerned though with wheel hop. Does any team out there have a fully stressed CBR? Does play in the bolts introduce wheel hop?

[Denny Trimble]

Have you experienced wheel hop in the car, or are you just worried it might show up?

We have semi-stressed F4's, and one time the removable frame member loading the engine in torsion broke. Worst wheel-hop I've ever felt... really nasty. But, those frames sucked, and relied completely on that frame member for torsional stiffness in the engine bay. We've improved since then.

[Scott Harsila]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> But, those frames sucked, and relied completely on that frame member for torsional stiffness in the engine bay. We've improved since then. <HR></BLOCKQUOTE>
Hey, I take offense to that! ;-)

[Denny Trimble]

Well, we've improved in the frame area, but there are still a few parts that won't pass the Harsila Finger Test (or the design review equivalent)...

I remember in '98 when 1000 ft-lbs/deg was our frame stiffness target...

[Tony K]

Last year we used a fully stressed 02' R6 engine, but we use a stressed drivecase as well, so the engine is turned 90 degrees. The rear roll hoop braces to the drive case to increase lateral stiffness and torsional stiffness is achieved by a pair of trunions attatching to the lower rear part of the engine. Seemed to work pretty well, we've been driving it for quite some time now and haven't broken anything yet.

[alfordda]

Denny

I can back up you comments about wheel hop. We had a couple of engine mount bolts either break or fall out. It wasn't too bad in corner entry and straight line accel, but that whole application of power on corner exit was a killer. Somehow, I managed to pull off a 61 sec lap on the version of the 98 endruance we were running, before we realized what was wrong.