Tensile and compression in Ti conrods.

[Boosted LS1]

^ Thanks. Chevrolet ls9 corvette, standard issue for a petrol engine with a supercharger. They won't cost F1 money

[knighty]

dont you mean LS7?....or does an LS9 exist?......if they are the same parts, yes they will be lighter than a production forged steel, or sinter/powder rod, but they are not lighter than a machined billet steel rod........I remember reading on an LS type forum that the production LS7 titanium rods were actually quite heavy for what they were......but if they are fit for your application, and they are light enough, I'd say go for it!

The race titanium rods I have seen from Pankl are billet machined, so yes, I'd agree those in the pic are production jobbies........they do look very diesel like though!

[Boosted LS1]

^ Thanks Knighty, the Ti ls7 rods are appx 480 gms iirc. My Ti billet rods from Crower were 500 gms but looked far stronger and were larger on the beams. The rods in the pic are certainly for the ls9 which should be in production at the end of the year? In my mind the ls7 rods would be suspect for big power hikes/rpm's as the wedged little end looks like an obvious weekness especially if you're hanging a forged piston on there instead of a eutectic lightweight. That said, they say the engine was routinely tested to 8k rpm's where it made no real power due to the camshaft.

The ls9 jobbies do look the business. It's a 6.3 s/c engine and I'd guess the raised piston dome may not just be about chamber burn but could also be there to allow clearance for the rod end. I've yet to see the underside of the piston.

[knighty]

the wedged/truncated/tee-pee (take your pick!) small end is a trick from low revving (5000rpm max) turbo-diesels......it gives more bearing area where its needed, as the worst forces are compressive from the high compression ratios and very high cylinder pressures in turbo diesels......but if its going to be revved to 8000rpm, I'd say no way, I'm surprised to see they have done this, but it may actually be for piston cooling reasons, and not bearing loading, as the piston might have a oil cooling gallery, hence the small end has been re-packaged accordingly.....I'd say stick with a conventional parallel wall small end.

I just had a rummage through my notes and found some handy weights for you

4cyl 2.0 turbo WRC spec con-rod, capable to 500bhp & 600 NM torque, I-beam forged & machined billet steel, total weight including bearings and bolts = 598g

4cyl 1.6L NA con-rod capable to 220bhp @ 9000rpm, H-beam (carillo style) forged & billet machined, total weight including bolts & bearings = 408g

Edited by knighty on Monday 28th January 13:20

Edited by knighty on Monday 28th January 13:26

[Boosted LS1]

^ Thanks. The piston has a similar wedge so will have some extra boss area whilst retaining a very short pin. Maybe the extra boss in the piston is to provide strength for tensile loads.