I am new to karting so this could be a silly question. I bought a brand new engine when I first started racing, and it’s due for its first rebuild soon. I have a friend who started karting at the same time as me, and he just got his engine rebuilt (he bought it second hand). My engine always appeared to be quicker than his, until his rebuild a few days ago. All of a sudden he is now passing me on all the straights.
I heard from someone that engine builders can change the timing in an engine to make it go faster, but this was just in a passing comment and I didn’t really get to ask any questions.
Does anyone know of some ways to find some extra pace in an engine rebuild?
This sounds like his engine was due for a refresh and now it is performing at its best again.
The Builder may have changed the timing, but you can’t think of it as increasing power, timing will only modify the power curve, making the peak power high or lower in the RPM range.
Naturally this will suit some types of tracks better than others and you can use the timing to better tune an engine to a circuit. There are many other better and easier ways to tune a engine to a circuit, but it can be done.
“Does anyone know of some ways to find some extra pace in an engine rebuild?”
This is such a broad question, and why engine builders are on the big dollars.
KA’s are a great parity engine the difference between engines, even between “the Best” and just an average one are quite small, within a couple of %.
It may not feel like it when your mate breezes past you down the straight, but your mate May have had to learn to drive “underpowered” so making a good corner exit has been more of a priority for him, so when he finally got a fresh engine it really made a difference.
You raise a good point when you said he had to learn to drive underpowered. That is probably quite true. Can I expect much improvement in pace once I get my rebuild, or is it too early to tell since it’s a brand new engine?
It depends how many hours you have on your engine really. I wouldn’t expect a huge improvement if your engine was rebuilt with under 10 hours on it.
But above that I would expect improvement, how much really depends.
Bill is making good points. Racers often are looking to buy speed (motor, tires, chassis, etc, etc) when in reality, we should be looking in the mirror. The driver makes the difference more than anything else. This is a post from another thread:
Driving is worth seconds.
Chassis tuning is worth tenths.
Engine is worth hundredths.
Prioritize accordingly.
However, with that said, Your equipment does need to be in good condition. If your motor has more than 12 hours it is likely in need of at least a top-end rebuild. Will you suddenly have more power and speed…probably not. You mentioned you are new to racing, in my experience with my son and I racing KA as well as seeing new karters at the track, it can take seasons before you are on pace with the fastest guys at your track. Some karters have more talent or other experience but a racing kart is its own animal and it takes time to master it…if ever!
An engine builder is going to “blueprint” the engine when they rebuild it to tune in all the tolerances. There is more power to be found from a “blueprint” and refresh, but it will be minimal. Things have changed since they introduced the engine in 2017, but I ran the whole national season on one stock engine out of the box and was on the podium multiple times. There is a bit to be found now on the engine, but again, minimal lap time.
There’s ignition timing and port timing. It’s possible that the ignition timing was changed to a setting that’s more suitable for the track. Full advance is not always the way to go.
Port timing there are strict limits on, but a builder may take time to ensure it is right at the limit.
Effect of these are pretty nuanced though, unless they were way off, to the extent that they were worse than stock.
Looking to update this topic. I had a chance to check out a new this season KA100. The timing range appears to have changed. The minimum timing is slightly over 2mm (2.03mm) and the recommended max is 2.69mm (.106"). The recommended max isn’t even halfway in the range you are given. My motor is a 2019 and at max recommended I am about 3/4 in the travel of adjustment. Not sure what to make of this. Isn’t timing a tech item? Why has this adjustment change to allow so much more timing?
I’m a little confused by “recommended” max. Sounds like the recommendation has changed, but not the actual limitation, is that correct? You’re wondering why they would change the recommendation?
It’s common for engines to have way more adjustment range than is practical and/or legal to use. Disregard any range not being used, and set it where you intend to run it.