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Road Tuning

Variable Cam Control Tuning

Relevant Module: Practical Skills > Optimising Part Throttle Cam Timing

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Discussion and questions related to the course Variable Cam Control Tuning

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As this course has pointed out several times, not everybody has access to tuning with a dyno. I am one of those people.

So far this course has been fairly helpful and definitely makes this process look fairly simply to accomplish. However, this has made very clear one thing, and that is that tuning the variable cams requires a dyno. At least that is the only information that is presented. It looks as though it may be possible to get in the ball park by watching the fuel trim and the desired afr by the actual afr. So my question is, can this type of tuning be done with road tuning and if so, how?


You need a way to measure torque. You can uses tools that measure vehicle acceleration as way to get torque, but you have to be careful to duplicate the conditions for each test, and study the resulting data very carefully, and the results may on change by a few percent with each iteration.

If you don't have access to tools to measure acceleration or torque, the best advice is to leave the variable cam timing the same a the stock ECU. It will probably not be that far off. While the gains from having Variable Cam vs not are huge, the gains from tuning the Variable Cam from a factory setup or probably minimal.

Seriously, the best help we may be able to provide is to help you find a dyno. Where are you located? What kind of car/truck/utv/motorcycle are you working with?

I was afraid of that.

Located near Houston TX. Lots of tuners around, but the point of my learning how to do this is to do it myself. It is getting quite spendy to rely on a tuners.

One of the issues I am having is that I can't access my current MAP. It is on the stock ECU for the EVO 9 USDM and the ECU is failing and there aren't any reliable sources for mitsubishi ECU's now that they decided to discontinue there production. The only route is to test my luck on Ebay, which I have, and my ECU came from Iceland. The other route is to obviously go standalone. I have gone with Link G4+ Plug in Play. That is why i bought the ECU from eBay, so that I can have a housing to put the Link ECU in and swap back and forth as I take my time to apply what I have learned here. I have all of the software to read my current ROM so that I could use that info to copy and paste, but apparently I don't have the correct file definition to read my current ROM.

OK, good luck getting your existing maps to use as a base.

You don't need a tuner -- you need access to a dyno. I presume you want to do the tuning.

These guys both advertise they offer 4WD dyno rentals: https://www.kozmicmotorsports.com/ and https://cpmotorsports.net/our-services/dyno-testing-tuning/

Are you capable of getting your car setup to run 2WD only (i.e. remove a drive shaft or whatever is needed, and disable any traction limiting), or will you need a 4WD dyno?

These guys have a super nice hub dyno: https://theshophouston.com/dyno/

and I saw reference (20 years old) to a Dynapack at SGP Racing, but they might not be around an longer.

With a hub dyno you can't drive off the dyno accidentally, so a shop may be more open to a less experienced operator using the dyno themself.

With a roller dyno, many shops and myself will say we'd have to drive the car while you work from the passenger seat for your safety, the safety of the vehicle, and equipment.

If your goal is to learn to tune yourself, I think dyno time is money well spent.

The Link PnP comes with a startup file for the car, also available in the software installer which includes VVT table values. The values at WOT are likely in the ballpark of what you want, and then it depends how much time you want to spend optimizing them at partial throttle.

As far as I know, Kozmic and The Shop both use outside tuners so their dynos may be available while their tuner isn't in town or using it remotely. I'm in Austin if the Houston options don't work out for you for whatever reason.

Well thank you for that assistance. I would definitely like to learn how to do it correctly. having an experienced individual for guidance would be of great help if that would be apart of the deal. Haha.

We usually reply within 12hrs (often sooner)

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