Wheels or engine to lower lap times?

[Gravisman]

I’ve been club racing a 2015 FZ-07 for three years now and during that time have grown my skills to consistently battling for podium positions in the expert classes. After watching my latest race in which I finished third, my coach commented that I was clearly the best rider in the race, but I lost because the other bikes were just faster than mine. My bike has lots of racing goodies like aRacer ecu, r6 forks, hordpower airbox, and Penske shock with link, but I’ve left the motor bone stock thus far, also running plain old pump gas. 
 

So now I’m in a situation where every time I go down a long straight I cross my fingers and hope an Aprilia doesn’t come around me. If I want to throw some money at this problem and try to make my bike more competitive, where will I get the best return for my dollars? My top ideas are 1. Get lightweight wheels, 2. Build out the engine for more horsepower, or 3. Keep the engine as is but start splurging on fancy fuel like MR-12. 
 

Budget is definitely not infinite here, so curious if anyone has experience to have an idea of which of these is likely to yield the best drop of lap time per dollar. 

[cornerslider]

I'm in the same place you are...... My compression was slightly low. I just dropped my bike off at my tuner yesterday afternoon. He was gonna do a leak-down test to see where the issue is coming from.  I'm hoping it's just a valve adjustment. My 07 has about 10K track miles on it, and I've never checked the valves. My motor internals are bone stock, but I have most the parts you mentioned on my bike as well. If I had the financial resources, I'd go for lightweight wheels FIRST. That seems to be the best return on investment (from what I've heard). I've seen others experience what happens when you build a motor for more HP..... You end up with reliability issues. We are club racers, and we do this for FUN. For me, not finishing a race because a mechanical issue is totally unacceptable. If you run MR-12 in a stock motor, you likely won't gain anything. MR-12 is for high-compression motors. The stock compression isn't high enough to benefit from race fuel. I'd say buy some lightweight wheels, and keep "rains" on your current wheels -

[Paulb5950]

Lightweight wheels probably see the most gains id imagine. Less rotational mass and all. They definitely can get pricey quick tho.

[M, Hausknecht]

1 hour ago, Gravisman said:

I’ve been club racing a 2015 FZ-07 for three years now and during that time have grown my skills to consistently battling for podium positions in the expert classes. After watching my latest race in which I finished third, my coach commented that I was clearly the best rider in the race, but I lost because the other bikes were just faster than mine. My bike has lots of racing goodies like aRacer ecu, r6 forks, hordpower airbox, and Penske shock with link, but I’ve left the motor bone stock thus far, also running plain old pump gas. 
 

So now I’m in a situation where every time I go down a long straight I cross my fingers and hope an Aprilia doesn’t come around me. If I want to throw some money at this problem and try to make my bike more competitive, where will I get the best return for my dollars? My top ideas are 1. Get lightweight wheels, 2. Build out the engine for more horsepower, or 3. Keep the engine as is but start splurging on fancy fuel like MR-12. 
 

Budget is definitely not infinite here, so curious if anyone has experience to have an idea of which of these is likely to yield the best drop of lap time per dollar. 

Light wheels are great but their benefits are mostly to handling; they allow the bike to turn more quickly. Sure, the reduced weight on the wheels will help acceleration some, but not with top speed. Forged aluminum Dymags aren't cheap, especially if you typically use two sets of wheels. With equal riders, if you want to be competitive with Aprilias on tracks with longish straights, you need more horsepower. It is not difficult to get rwhp in the low 90s with stock pistons and bottom end. Ported and epoxied head, bored throttle bodies, and mild cams will get you there. I get nearly 92rwhp with a 10,200rpm rev limit on 100oct fuel.

Where do you race and what sort of lap times do you run? Which tires do you use? What fork offset are you using? The stock R6 triples aren't ideal if you're running a 180/60 rear tire.  

[Gravisman]

I’m in California, running in the 2:01-2:03 range at thunderhill. I’m sure it’s possible to go under 2 with this bike as is, but those seem to be pretty decent times for a mere mortal which are capable of fighting for wins. 
 

I do run stock r6 triples with a 30mm offset and 180/60 tires. Curious what sort of change you would make there.

I get that wheels will have little effect on top speed, but I deliberately phrased my question to ask which would most effectively lower lap time. Better handling (and acceleration and braking) can lower lap time even with top speed staying constant. 

[Gravisman]

22 hours ago, cornerslider said:

If you run MR-12 in a stock motor, you likely won't gain anything. MR-12 is for high-compression motors. 

FYI, this is VP’s description of MR12:

“We design MR12 to make maximum power in four stroke dirt or street bikes with stock or mild modifications. In fact, this is VP’s best fuel yet for 4-stroke applications that can tolerate lower octane values.”

https://vpracingfuels.com/product/mr12/?c=221&

Edited October 9, 2023 by Gravisman

[M, Hausknecht]

With the R6 triples and the larger diameter rear tire and the shock link the back of the bike is up pretty high. Additionally,  with the R6 forks (irrespective of version) being shorter than the stock forks, the front of the bike is really steep. You don't have much trail with the 30mm offset. I have a similar setup and use 26mm offset triples. I imagine your bike turns in well but is it staple mid-corner and able to finish the corner without additional steering inputs? Does it tend to shake its head under acceleration, lift the rear tire easily on heavy braking?

You're absolutely right that cornering and stopping are important to fast lap times but light wheels won't make as much difference as 15-20rwhp. I raced a Ducati on both stock aluminum wheels and on magnesium wheels (together 3-4 pounds lighter). The lighter wheels allowed the bike to turn quicker and with much less steering effort, but they didn't change my shift points or gearing needs noticeably like more horsepower does.

I'm an east coast guy so I can't comment on your laps times, like I could if I'd raced there.

[M, Hausknecht]

18 minutes ago, Gravisman said:

FYI, this is VP’s description of MR12:

“We design MR12 to make maximum power in four stroke dirt or street bikes with stock or mild modifications. In fact, this is VP’s best fuel yet for 4-stroke applications that can tolerate lower octane values.”

https://vpracingfuels.com/product/mr12/?c=221&

MR12 is horsepower in a can. It is also corrosive (need to drain tank and run  motor on pump gas to flush the motor out after use). It is also really expensive to run for a season of racing. It will give you at least 3-4rwhp, maybe a little more, once you've done a new tune for it.  

[twf]

Stock bike can do 58's there with good rider so you got more work to do on rider

Last couple seconds after that you will need motor work and great handling.

[cosp600rr]

I personally went with motor in mine. I did it to not get motored on the straights by the 660 in every race and to me it was worth it. I get 2 seasons out of the motor before a refresh without to much issue other than the motor is expensive and I run 100 octane fuel. I wont even put MR12 in any of my bikes because Ive seen so many bikes with fuel pumps go bad, injectors go bad, destroyed valves, fuel boiling in the tank and having to drain it every weekend and put pump gas in to flush the system. My engine builder actually told me he would not build a motor for me and tune it if I planned to use MR12. Just not worth the trade off. Im also still running stock wheels on the bike but is sure is nice not having to deal with the RS blowing by me on the gas.

[Gravisman]