[RS Barn]

I think there may be a huge difference in tuning with Race fuels. My 968 GT motor was originally tuned with VP C-10 racing fuel and had great results in power and seemed to run cool. Race fuel really seems to cool motor BTW. I only ran car at track one day and had added Sunoco 110 leaded at track which was about a 50-50 mix of fuels and didn't have any running issues. Temp was 90 and so was humidity.

At Mid Ohio this weekend temp was 60-70F and mixed Humidity. I added 10 gallons of 110 Sunoco.

I developed a misfire at 5-6500rpm. Checked plugs and color looked good and not indication of detonation. Luckily it got cloudy and I ran next session without sunglasses and could see A/F readout.

Yikes---I was seeing 13.4 to 14.0 in higher rpm ranges and pulled in. I was afraid to pull plugs and see metal on them. Luckily no problem though. I increased fuel pressure and went out again. A/F in mid 12's and no misfire. car also ran much better. I was killing 951's on straights. Not bad for a 3.0L NA with 300HP

My other concern was fuel pump delivery. Raising fuel pressure could have helped A/F but if fuel pump wasn't delivering it would have leaned out at high rpm.

Anyway 3 new rules

1. Install a live Wideband in any Race Car

2.Be prepared to change fuel mixture when using multiple fuels

3. Look at your plugs after Hot session-Old school methods can save money

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