I have read through a lot of threads here on cams with no tune, and I agree with what everyone says - just get a tune. But my situation is a little different. I road race with NASA, and to stay in my class Im allowed a cam swap but not a tune. I dont have to worry about driveability since its a race only car at this point but I do need to worry about the survival of my motor since it lives at high RPM. I can run any cam, lifters, rockers and valvesprings but stock heads and tune. It sounds like the hotcam is OK, but given the above, is anything bigger safe (305, 306)? Again, I know I'll lose power without a tune, and I dont care about driveability, but I dont want to burn up rings or whatever with a cam that will run too rich, etc. thanks

 

My GM 847 car ran really good with no tune.

 

Ive run the stock tune on my cc305, works alright just a little rich at idle. Just make sure you dont have false knock once you decide what to put in it.

 

How would they check for a tune?

 

Edit: There's a lot of area under the power curve available as long as you can use all aftermarket valvetrain parts.

Jon A did a similar thing a couple years ago:

http://web.camaross.com/forums/showthread.php?t=259094

Note the power gain around Jon's 6400 self-imposed rev limit. Your post suggests you might be allowed more than stock rev limit. If you are rpm limited there is still lots available with the right valvetrain. Probably even more today than when Jon did it. It won't be an off-the-shelf cam, however.

Jon discusses the tune a bit. You might contact him directly.

 

Very easy, download your PCM tables and compare to the stock tables for your car, there's a dozen comparison programs available to tell you the differences byte by byte of two files.

 

Not going to want to go real big because a big cam like the 847 mentioned above peaks well above the stock rev limiter.

So on carbed cars do they verify that jetting and distributor advance curve and all are perfectly stock too?

 

Since your not allowed a tune your going to want a cam that works in the stock rev range. The crane 227 or lingenfelter 211/219 would be good choices. And are you allowed to use a MAF translator? There are also tricks you can do without altering the tune to change the a/f if you aren't, like ported MAF ends will lean it out, put a resistor in the IAT sensor to increase timing, ect.

 

What they actually do to confirm you have the stock program is they put your car on the dyno (they have one at every race) and do consecutive dyno runs with your computers and a replacement they get from a junk yard or wherever - that you have to pay for. They have to put out essentially the same power. They actually do this stuff if they're suspicious, and you have to pay for everything. I've already taken points for "changing a sensor" (this was the LT4 knock module). I wonder if using a MAF translator would qualify as a "sensor" change? I already have the MAF ported. I wrote to Bret Bauer and linked this thread, maybe he'll chime in. Thanks for the input guys- How much would a MAF translator help?

 

SSTAT,
I live in Ohio and will have my TA out in the next week or two. You are more than welcome to test drive it with the CC-305 and Stock Tune, plus it will have a brand new viper internal T-56 and pro 5.0 combo you could row gears on. I will make sure its in top shape so you can get a feel for the cam if you want to drive it.
Josh

 

I'd look at who they dyno, especially if they are suspiciously fast, and see if they "pass" the dyno test. If they do, and they are noticably faster, but have about the same dyno power as you other guys, they might have found a way to work around the rule. This isn't the first class nor organization to try to control power via the PCM, nor would it be the first time folks have tried to work around such a rule. Generally the best racers are smarter and more agressive than the inspectors.

Some folks look at racing "rules" as "suggestions". Whether or not you search for a way around the rules is up to you. If others are bending the suggestions, and you need to be competitive, you'll need to respond in kind. I don't think folks who do this are going to talk about it, especially on the internet. It only really comes out when someone gets caught.

 

You supply both PCMs?? Sounds like a no brainer. Load the same bin file onto both. There are more than one base files for each model year so how would they know??

Reminds me of a friend who races a circle track 4 banger honda. The tech inspector made him pull the valve cover to make sure he wasn't running DOHC. Retards.

 

how do they know if your tuned...get the wot tuned and part throttle touched u so it wont die...but still run rick ect so no1 will know

 

SOLID ROLLER! A short duration solid setup will gain more power through the entire rev range.

 

Seems like it would lead itself to false incrimination. The PCM has long term fuel trims, and based on them, it can affect the WOT a/f ratio depending on what cell and BLM the PCM was at right before WOT was entered.

To get around this issue, make sure your PCM is reset right before you dyno it so that it loses all LT fuel trim data and compares accurately to any other stock PCM.

Dan