Rods

[Porsche 935]

What rods are you using in your 700plus hp turbo engine?

[voitureltd]

Carillo in one and Pauter in another. Both No Probs, so far.

[Menmojo]

Pauter. 733rwhp with 655ftlbs torque.

[flashgordon64]

Wossner

[Tippy]

What's wrong with stock?

[voitureltd]

Originally Posted by Tippy

What's wrong with stock?

The one now with Carrillo had stock rods with ARP studs. One bent on the dyno and caused the need of a crank, both case halves, oil pump, cylinder barrel, piston so a complete engine redo was needed ( well over $15K ). Stopped keeping track of expenses. Badnews. Dyno results were under 500 wheel HP at that time so to me if your going for that kind of HP better rods are a good investment. Here are some current photos of the redone motor using what good stuff that was left. The upper motor was originally by Jarvis however he just did from the heads up so no aspersions on him.

[voitureltd]

Originally Posted by Menmojo

Pauter. 733rwhp with 655ftlbs torque.

Richard. That car needs some nice trac tires for Porsche DE so your silver one can take a deserved rest for part of those days .

[boosted79]

"stock rods with ARP studs. One bent on the dyno and caused the need of a crank, both case halves, oil pump, cylinder barrel, piston so a complete engine redo was needed ( well over $15K ). Stopped keeping track of expenses. Badnews."

Ouch. Good rods are cheap compared to what happens if the stockers don't cut it.

[Porsche 935]

I am looking to replace the aluminum ones in the engine, pushing luck with 23 years of use. Also I have seen stock rods break, especially if used on a regular basis over 7,000 rpm. First I have heard about wossner. Are they special made or stock item?

[Porsche 935]

Wossner said no. Oliver said they could custom build a set. I have oliver rods in my 2,000hp big block. Still have not heard from R & R.

[xbmwguy]

Pauter 703 656 torque

[Porsche 935]

I saw the Pro H Carrillo rods for sale on amazon for $1300, sounds like a good deal.

[TurboKraft]

Pauter Turbo: 800whp/680wtq and 7,500rpm
Carrillo w SRS-CARR bolts: 819whp/693tq and 7,000rpm
Stock rods, peened & polished, with ARP: 752hp/693tq and 6,500rpm -- total scope-creep project, and if starting the build from scratch we would have used Carrillo or Pauter.

There are some people who are opposed to Pauter rods vs. Carrillos. In our experience, both are very good. Design differences may be argued if building for the highest level of motorsports endurance racing, but for 99.9% of the projects on this message board they are interchangeable.

A few other thoughts:
* We've never seen an ARP fastener fail where it's the fastener's fault. I've seen broken rods from 3,000hp blown big block V8s, and the ARP bolts were intact. Failures are usually related to installation and/or torque.

* Pauter usually offers rods in 3 different weights: lightweight, standard, and Turbo.

* Carrillo offers rods with both cheaper WMC6 bolts, and SRS-CARR fasteners. WMC6 bolts aren't as strong, should be measured with a stretch gauge before and during installation, and should be re-torqued (stretched) a limited number of times. SPS-CARR fasteners should also be measured, but can be used repeatedly -- a lifetime fastener.

[Porsche 935]

That must be the difference in price, the carr bolt option is about $250 more. Now in the same price range as the Pauter rods. I am not road racing. Big HP street car with higher rpm 1/2 and mile runs.

[stownsen914]

Turbo noob question: I've always thought racing rods were needed due to high RPM usage. I'd have thought that boost would stress rods compressively, while a more common failure mode for a rod is to basically separate due to rod bolt failure (or rod breaking I guess). It's not surprising that forces from turbocharging stress the rods, but does it demand non-stock rods if high RPMs are not anticipated?

[boosted79]

High boost at low rpm can bend some stock rods, not sure if that is a problem on these engines but is on others, esp. with twin turbo setup.

[Porsche 935]

Pauter is going to make me a custom set in case I ever turn the boost up and push what the turbos are capable of.

[TurboKraft]

Originally Posted by boosted79

High boost at low rpm can bend some stock rods, not sure if that is a problem on these engines but is on others, esp. with twin turbo setup.

Not on these, the rods are (a) really short relative to stroke at just 127mm, and (b) pretty massive.

[Tippy]

Originally Posted by boosted79

High boost at low rpm can bend some stock rods, not sure if that is a problem on these engines but is on others, esp. with twin turbo setup.

Not saying you're wrong, but I don't see how that's physically possible.

[boosted79]

If building a torque monster and size the turbo(s) to jam in a lot of boost (and fuel) at low rpm the force on the rod can exceed it's buckling limit esp with a lot of advance so cylinder pressure spikes at TDC or right after when the rod to throw angle is large (180 deg at TDC). The low rpm means forces on rod from the combustion pressure last longer vs. high rpm. As Chris said, it depends on the rod ratio, cross section of rod, etc etc but a higher rod ratio (longer rod, shorter stroke) is more prone then lower rod ratio.