You can still purchase the two back issues with all of the results. Call DSPORT at 714-593-0280 and ask for Jeren.

 

This post is more to do with the infinity and not the cam test, but I am intrigued about something. If I understand correctly, the Infinity was basically set in closed loop and used wideband 02 feedback to correct the VE curve.

I am wondering how logn it took for the infinity to dial in the feedback and what the process was. Was it basically instantaneous, i.e. change cams and let her rip or were several dyno runs were required with conservative timing settings to avoid it leaning out and blowing up?

I ask because I always read that even when using a wideband closed loop is to be avoided as feedback may not be fast enough to prevent a lean condition. I guess his woudl be a testament to the speed of a higher end ECU like the infinity.

 

Hi Wreckleford,

Sorry for the delayed response. Yes, the AEM Infinity works somewhat like how you mentioned. Here's a video that we produced for AEM to help explain how the unit works and the benefits of VE-based tuning. Simply put, if it was not for VE-based engine management systems such as the Infinity, we would be forced to re-tune the vehicle after swapping each set of camshafts. In addition to much more work and time on our behalf, this would have also created a huge variable in the test that could not be wholly accounted for.

Best,
Jun

 

First time reading this thread. Props to DSport for putting together the test.

 

I didn't see this reply before. Thanks for that and posting up the vid.

 

Great information!

 

FYI, this info is now available online from DSport. And you should also subscribe to their mag IMHO.

http://dsportmag.com/the-tech/showca.../engine-build/

 

Dang, the S3 pull away from the R2's after 4500rpm... Too late to change now lol

 

I think it would be interesting to see the cams on a stroker, since that's what they're designed for.

Or a back-to-back on a stoker

 

This.

The R2s were built to be run on stroked engines. If you're running it on a non-stroked engine you're gonna have a bad time.

 

A stroker engine will simply shift the power and torque curves to a lower RPM. In very simple terms you can make and adjustment based on some simple math. If you want to compare a 2.0L to a 2.3L, the difference is 15 percent displacement.

In basic terms, the power seen on a 2.0L at 6000 RPM, should be the same as the power seen on at 5,250 RPM (6000/1.15). At 8000RPM on the 2.0L, you should see the same power at 6,950 RPM (8000/1.15) on a 2.3L.

Bigger cams will tend to have a smoother idle on larger engines too for the same reason. If a 2.0L engine needs to idle at 1,000RPm with a radical cam, it will only need to idle at 870RPM (1000/1.15) on a 2.3L.

This is a simplification, but it's generally pretty spot on.

Hope that helps.

Read more dsport at dsportmag.com or better yet subscribe

 

In my past experience that hasn't shown to be the case. I have witnessed a 2.4L with GSC S3 cams idle roughly.

I get your math for the idle. However your statement has me confused.

A lower idle allows the engine to idle more smoothly? Could you please elaborate?

 

I thought people were having issues with bc cams like falling apart that could be why?

 

A larger displacement engine will be able to have the same quality of idle at a lower engine speed (RPM) than a smaller displacement engine running the same cams.

If you had a smoother idle on a 2.0L than on a 2.4L with the same set of cams, your cam timing is off on the 2.4L engine. All things being equal, bigger engine means smoother idle at the same engine speed. Or it can mean being able to turn down the idle RPM on the larger engine to have the same quality of idle as on a smaller displacement engine.

It's pretty common for cam timing to not be adjusted properly and we've also seen a number of manufactured cams to be off by 1 to 10 degrees. If you are using a 4G64 block and you do not compensate for the increased deck height by dialing in your cam timing, lots of problems will occur. To prevent this issue on any of the 4G64 builds that we do in our machine shop, we will re index the timing gears so that the marks still are useful.

 

YA but thats not a stroker setup which the r2s were designed for.