I need your advice for the driving choice of connecting rods

[935TURBO]

Following the upgrading of my 930/66 engine, I need your advice for the driving choice of connecting rods......

As the goal is to get round about 500 hp, with a good torque since low revs for a track use mainly and 20 road, shal I :

- use the stock rods
- use Pauter rods
- use Carillo rods


Thanks for your feedback....

[lucittm]

Serge,
I believe the conventional wisdom is that the rods you choose depend more on the top RPMs you expect to encounter. The rod strength is tested when the piston is flung back up toward the head during the exhaust stroke, at high rpm it is the only thing holding that chunk of aluminum away from crashing into the head. At 8000 RPM the speed of the piston in meters per second is, um, pretty fast. Horsepower is a secondary concern, all rods are very strong in the compression (downward) vector and this is not a normal failure mode.

If you are not planning on any RPMs above the current redline (and you have a reliable rev limiter), I think stock rods are fine. But just one occasion past 8000 RPM (plus or minus) is enough to do permanent damage.

The choice between Pauter and Carillo rods is a personal choice depending on price and availability and I think both are good.

Mark

[voitureltd]

A stock rod bent when on the dyno on a motor I had bought. The upper twin turbo motor was done by Jarvis who did not build the lower motor.so it was not their doing. The sheet showed the failure @ 5200 RPM on the way up past 500 RWHP. It had lots of dyno time thruout the RPM range so could have been stressed from a previous pull. ARP hardware was used when the lower motor was built by others. We now use JE pistons & Carrillo rods, however Pauter was considered but Carrillo chosen as a set were available at the race shop. For the price of a set of either of these rods VS checking the stock rods and the ARP hardware cost is good insurance and allowes for future performance upgrades. When it bent it ruined the whole lower motor, crank, block, oil pump etc, and contaminated the entire oil system so everything had to be checked for damage and cleaned of metal fragments. Obviously well over 10K to put it right.

[Tippy]

Got nothing on the rod choice but my money shift produced over 9000 RPM with stock rods and bolts without failure.

[Flieger]

Well, any column (connecting rod) is better in tension than compression because buckling failure will almost always happen at a lower stress than the tensile stress fracture. The weak link that makes swinging the piston over the top of the exhaust stroke is the rod bolts and cap. There is a lot less metal down there holding the rod and piston on to the crankshaft than there is on the other side.

[935TURBO]

Thanks for your answers.....I wonder if it's necessary to invest money in Pauter or Carillo rods, as I already balanced the stock crankshaft and rods.....my goal is to use the engine with enough reliability at 8000 rpm.....I'm at the beggining of the assembly for my new 3.5 TT engine and don't want to have to open it in the next few years....


As I showed on this thread, i had problems with my other engine...a rod screw broken at Le Mans......



934/935 turbo SE, my street REPLICA....Story.......

[turbo nut]

You have seen the results and are paying for parts breakage in the bottom end. For the piece of mind and if you are going with a 8000 redline. I would step up for a set of rods. In the big picture fairly low cost.

[David]

I went with Pauter for the piece of mind. Another benefit is the lighter weight. 6 Pauter rods weight about what 5 stock rods weigh.

[935TURBO]

Is there somebody here using Carillo.....and are Carillo and Pauter equal reliability/performances...?....and where did you buy yours...?

[tom84930]

Might want to look at R&R rods from Charles Navarro.

[JBL930]

I know RS Tuning use Carrillo, probably the most successful Porsche race engine builders out there, so a safe choice. I think you will need to machine a little off the oil pump for clearance, which will require you splitting the case. I may be wrong, but i know that is necessary with the 993. I went with Arrow rods which were more expensive, but didn't require the machining, so it worked out better for me.... But they only do them for the 993 as an 'off the shelf' item. When i asked Pankl they only do them to order, and they were seriously silly money....

So your choices are Carrillo and Pauter I guess, or have a look at the R&R ones mentioned above

[JFairman]

I think you can install Pauter rods without grinding some metal off the oil pump housing for clearance but I'm not sure about that.
Post on the engine rebuilding forum for more answers to questions like that.

[935TURBO]

Thanks to you guys...I started to read the thread you mentionned...hope I'll all understand....there's a lot of litterarture....


I have to precise that at present, my new engine is completely in spare parts....the engine case has been machined to fit the 3.5 Mahle cylinders and the crank/stock rods have been balanced...the engine I'm re-building is different from the one which is broken....


So, before starting the rebuilding, I want to be sure to make the right choices and take the good decisions.....

Thanks for you help.

[the_preacher197]

Originally Posted by tom84930

Might want to look at R&R rods from Charles Navarro.

I was wondering about those as I've seen them on LNE's website.

Were they used in your build Tom?

[935TURBO]

I found this for R&R..... R&R Racing Products Custom Pro-Series Billet Steel Connecting Rods http://www.rrconnectingrods.com/catalog.pdf


Does someone have an idea about the pricelist....?

[935TURBO]

Is that the price for a set...? 1 699 $ R&R Pro Billet Chromoly 4340 Steel Connecting Rods

[voitureltd]

Originally Posted by JBL930

I know RS Tuning use Carrillo, probably the most successful Porsche race engine builders out there, so a safe choice. I think you will need to machine a little off the oil pump for clearance, which will require you splitting the case. I may be wrong, but i know that is necessary with the 993. I went with Arrow rods which were more expensive, but didn't require the machining, so it worked out better for me.... But they only do them for the 993 as an 'off the shelf' item. When i asked Pankl they only do them to order, and they were seriously silly money....

So your choices are Carrillo and Pauter I guess, or have a look at the R&R ones mentioned above

Yes, with Carrillo you need to machine a little off the oil pump.

[Flieger]

Wow, 1700 a set

R&R Pro Billet Chromoly 4340 Steel Connecting Rods