This is Brent from Brenspeed, Chandler typically makes posts but sometimes he sends something my way if he thinks I should see it, so here is my reply.
I have always said Forums are “typically” a good place to get and give information but a lot of times (like this one) false facts are thrown around and bad information is pumped out. I have been tuning S197’s since the day SCT had software available. I remember way back when the software was released you couldn’t even data log them because at the time the programmer was an Xcalibrator 1 and you couldn’t even pass through data log. Since then I have put my tunes on an absolutely ridiculous number of 3V cars. Just from 12/1/2010 to 12/31/2010 I put my tunes on 1,531 3V cars (in house and mail order). That’s more 3V cars than some shops ever tune. This doesn’t include revisions for upgrades either so when I read somebody say the tune 100% caused a problem or refer a shop that just bought tuning software a year ago and doesn’t own a dyno and tuned a hand full of cars, if that, gets frustrating.
The car in question has run fine for a year from what I have been told and supposedly all of the sudden had detonation. There are so many variable that can cause that and we are only talking about a car that makes 530 to the wheels here not a 700+ rwhp car. A car that runs a less aggressive tune than our automatic transmission NMRA cars that make a couple hundred passes a season. Did the car get a tank of less than the desired octane? Did some oil work its way up into the inlet or blower which will cause detonation? Etc…. Its hard saying, but to just up and blame a tune that has been on the car for a while sounds a little odd especially one that is not crazy aggressive.
Roy your tune was not so aggressive as you can tell by the dyno numbers to be the cause of your issue. Your 93 tune only runs 16 degrees total timing, and your 110 race fuel tune runs the same timing schedule we run our race car on with 93 octane. This will not cause your car to detonate. Yes we run more aggressive tunes on our cars we race but this is for R&D purposed to see the limits of the engines. Yes we do use the IAT for protection so yes on the dyno if it is not cool numbers do not come out as high as some people want. It’s not that the dyno has a 50HP variance, it’s that fluctuating IAT (which adjusts spark) can cause a big HP variance on blower cars.
I am just stating facts from our side. And I know you are frustrated also just stating what Jim told you. I am not mad at you for this. I do think it’s ridiculous to find this post and never get a phone call from you beforehand so I can explain your tune. I do apologize if you wanted a video of your car and didn’t get it. My tuning schedule does fluctuate sometimes if a car is ready for the dyno or a previous appointment cancels and I am able to get on it I do.
Brent
