Rolling Resistance, Drag and Aero effects of changing rim spec

[CrisSilberGrau]

Couple of other things...

We're you drafting a car in front?

one thiing I ran into was I was often not fully depressing the throttle

No I was not, both laps (actually the 4 lap references), are all full out 10/10 laps that I was going for time.

Tire differences - Yes, this was mentioned in my post, and as well rim difference. Faster top speed and accel was EC7R (19.9lbs) with TrofeoR 265/35/18 (24ish lbs)
Tire pressures - This is yes always BUT at my cars weight and the tires I used pressure was set for HOT at 30-31 psi MAX
DSC Intervention - No both times, DSC is fully off

The only system that was intervening more the second time was ABS into the heaviest braking zone at Mosport, Turn 4 into Turn 5. 180-190kph to about 100 in the span of aabout 50-75feet into a compression then going uphill about 3 stories for a hairpin. Extremely butt clenching when it happens and the car wont slow down fast enough.

I had the same aero last time just didnt trust it, now I do and I can take more speed through turn 4.

[CrisSilberGrau]

Ive decided to really go for it this year in terms of time. I am very fixated on breaking that 1:30 barrier at Mosport. I'll be putting on the injectors ive been sitting on for about 2 years with accompanying radium hardware, I've gotten the vorshlag non M top hats that will allow more than -4deg camber up front (currently maxed at 3.5), and some custom carnards are being made this week to help with diverting some of the high pressure frontal air into the low pressure foil around the car and up over the roof to the wing.

Unfortunately, all these will be enough of a change to not have comparable data to the other times, but as you guys mentioned the data never really was similar due to so many factors. Excited to give it a go.

Also the front triangulation mod is really calling my name man, I've wanted a SLON bar for so long but cant justify literally 8k CAD for a strut bar landed at my house. I'd love to diy it and see the benefits that everyone is raving about.

[bigjae46]

One more thing - tire outer diameter. Same size tires can have different ODs.

I'm not saying that wheel weights don't have an impact, I don't think it is that significant. I could be wrong.

[CrisSilberGrau]

One more thing - tire outer diameter. Same size tires can have different ODs.

I'm not saying that wheel weights don't have an impact, I don't think it is that significant. I could be wrong.

Your first point is correct, of course. And I did consider it. I went from a 265 on a 9.5 rim to a 10 rim. Something I will note that jumped out at me. The TrofeoR was the most bulgy 265 tire I've ever mounted on a 9.5 rim, and I had 275 RE71RS, 265RS, 265RS4, 265CRS. It was the only tire that would rub in the rear with a 12mm spacer which was required for track width in the rear due to ET35 offset.

The other main point of concern is the E88s being wider up front and considerable more poke can/will cause more frontal aero drag, and at the worst place imo. Where the high pressure slow air turns the corner and converts to low pressure it hits the tire. I may be wrong and it may be a super novice take but it would help explain things, plus a head wind or more adverse wind conditions.