2021 l28et connecting rod questions, OEM limits, Forged options, etc

[Sideways]

Heylo everyone!

So Ive been digging around for information on l28et connecting rods- and theres definitely some good info floating around, but i realized something- The majority of the threads are 10+ years old- So I figured id start something new.

First question- What are the general "limits" of the stock l28et connecting rods? Ill be up front and say Im shooting for a goal of around 500~ whp- And am wondering how well the stock rods would hold up to this. Ive seen a couple of mentions here and there from old threads that they can. But more info is always appreciated.

Second- What companies are making good forged connecting rods these days? I remember a handfull of years ago it was easy to google "l28et connecting rods", and find a handful of companies with them readily available. Not all im seeing are companies like CX-Racing and Maxpeeding. Now while I like CX-Racing (I actually use a handfull of their parts on my car currently. In particular ive got one of their t3t4 turbos. Ive been making about 300~ whp on my L28 for over a decade with the thing with no issues), im a bit skeptical for something like a connecting rod.  Maxpeeding have had mixed reviews when I see people take precise measurements- So im curious about options elsewhere.

Anyone have any good suggestions for good connecting rods today in 2021?

Thanks everyone!

Edited June 24, 2021 by Sideways

[evildky]

Sorry I'm not mush help here but the stock rods are plenty beefy, there were guys making big power on stock rods a decade or two ago. There might be something said for the reducing the rotating mass wiht newer engineered rods, the OE's are beefy making them strong and heavy. Id hazard a guess you can improve strength and reduce rotating mass wiht a newer engineered rod. just my .02

[calZ]

The semi-recent conversations I've had with people who know a lot about the L-series seem to peg the stock rods at ~100hp each before you're playing with fire. I believe Carillo still makes rods for the L. Pauter too. If they don't list them on the website, give them a call. You can always order custom as well. 

[AydinZ71]

@Sideways 

 

Best place to start would be “maximum boost” by corky bell (if you have not already)

 

you will learn that there are significant inertial forces on the rods that increase exponentially with RPM, irrespective of torque. Then… there is torque. The stock rods can handle a TON of torque at low rpm’s precisely because they have so much material and are heavy. Most folks with L28et’s go for more torque than power so they let off at lower RPM’s. That’s because the P90 head doesn’t flow all that much air compared to modern heads, so she naturally falls flat over 5k under heavy boost. At these lower RPM’s (3-5k) the stock rods can can handle well over 400 ft-lbs in my experience. Not enough experience for me to say above 500 ft-lbs. 

 

back to the inertial forces, the heavy stock rods hurt you here. Piggybacking on Greg Ira’s experience with SCCA EP built motors, he sees the rods being a weakness above 8000 rpm due to inertial forces. Keep In mind, we’re talking an NA 2.4L race motor with no more than 170 ft-lbs of torque. These are the inherent forces due yo rapid acceleration of the rod (up-down). Hence, a more modern rod that is equally “strong” under torque yet lighter than OEM will overall handle a lot more power (which is a matter of torque X rpm). 
 

so yo answer your question fully, I’d say this: if you are building a conventional L28et with a bigger torque number than power, you could probably stretch the envelope above 400 and who knows… maybe 500 ft-lbs, with stock rods. I wouldn’t personally… but I can’t say it would fail for sure.

 

however, if you want to make real power which requires moving that torque band HIGHER on the RPM band, definitely go with modern, efficient rods. That’s my plan. 
 

Pauter is a great rod vendor here in Socal. They have a “lightweight” L28 rod for NA racing application with light torque, and their standard improved rod which will handle a ton of torque but is still lighter than OEM. I got a quote recently at $1,500 for a full set for either option. Give them a call and tell them about your needs. They know what they are doing. 

[TomasTag]

I have more specific question directly on the forged conrods once decided to use. As @Sideways said , too many old posts can't really find the info if exists somewhere. 

 

There are a bunch of suppliers - so called manufacturers who just import from China , brand them and sell them . I recently got a set of brand new forged conrods.

Unlike OEM I've seen (not for this engine by now) the cracked rods type, very easy to detach from the crank once the bolts were loosen. 

But these forged whatever China rebranded, are having some guides which are DAMN tight. I had to hammer them with a plastic furniture hammer several times, to release the big bore bearings retainer. 

Now my question is:

Wasn't these rods guides supposed to be conical? To align the big bearing bore 2 half pieces just in the last millimeter of the bolt guides ? 

How can these be disassembled later on for any maintenance or inspection rework?

I'm sure hammering into the rod directly on the crank shaft, is NOT a good idea, even if with a plastic hammer.  

 

Thanks in advance to whoever helps with the info.

[jonbill]

I have rods from Maxspeeding rods in my current and previous engine. I have very close tolerances between piston and head and no contact and no problems at all. I'd recommend them.