Re: Planning for and minimizing maintenance

Again, i'm not too knowledgable on engine building... I don't see how being over/under square would change a darn thing. As far as R/S ratios...  honda's B18c has a R/S ratio of 1.58 and they rev to 8k stock....  I suspect the R/S ratio is not the issue.  Perhaps its the ratio of R/S to rod journal diameter? I could see how less surface area could be a problem depending on the direction of forces imparted by the R/S ratio.


I've been thinking more about this and perhaps the issue could also lie in cavitation of oil in the oil pump?

I'm sorry, i'm not saying that anyone is wrong here, i'm just saying i think there's more to this than meets the eye. And if i can indeed get to the bottom of it, perhaps i can make everyone's day better?? smile

Re: Planning for and minimizing maintenance

The higher the stroke to bore ratio, the more rotational inertia the motor has. High rotational inertia requires lower RPM for the motor to stay together.

Lower stroke to bore ratios (think F1 engines) have low rotational inertia and can therefore rev to high RPMs.

Honda tends to build motors with higher ratio because that helps to increase engine efficiency, which is what you want when you're designing a motor for an econobox.

The factory internals are designed to withstand "normal" loading and operating conditions. Run them at or above their limit in an endurance race, and well, that's a recipe for making shrapnel out of your internals. Sure, you could get all cheaty and build up a race motor with fully forged internals, H-beam rods, etc. and rev the piss out of it, but then it's just more expensive when you overheat it and blow up anyway.

Sorry For Party Racing! - 1985 Pontiac Firebird - Car #35

A race car exists only in two states: broken or in the process of becoming that way.

28 (edited by roger.bladek 2016-09-29 11:55 AM)

Re: Planning for and minimizing maintenance

Hispanic Panic wrote:
Sonic wrote:

Oil/cooling: This is where most Honda teams fail.  The ones that don't know that you need a big ass oil cooler and radiator, and to run serious oil. We have 18k race miles on our D16y8 like this.  A DA automatic w/AC radiator is twice as thick as the EF part and bolts in.  We also have a remote mount oil filter with a huge filter, on the way to the big ass oil cooler.  We run Shell Rotella T6 5w40 diesel truck oil, and it has been excellent.  We also have a ported oil pump, a weak point on these cars as they cavitate at high RPMs  (http://www.theoldone.com/articles/d_ser … ding_tips/)

I've been thinking more about this and perhaps the issue could also lie in cavitation of oil in the oil pump?

Sonic mentioned this in his first post. The link he posted has a DIY for oil pump and block porting. There are a few more DIY that can be found on the d-series forums. This is the one thing that I did not do to my car, I also don't intend on reving above 5500ish.

29

Re: Planning for and minimizing maintenance

Hispanic Panic wrote:

I think the point i made earlier is that if you're doing everything you can for the oil, i don't see why you couldn't increase the rev limit.

Everyone has told you not to raise the limit, several have told you to lower it. You'll have enough trouble your first race anyway, no need to amplify problems.

My thoughts: It costs a lot of money to race in Lemons, if you tear up the car the first hour then the rest of the weekend isn't much fun. Once you've run a few races and you've deemed the car "too reliable" then raise the rev limit.

Re: Planning for and minimizing maintenance

Here are the important questions.

1. How many seconds a lap are you really going to gain by bumping your rev limit up by 500 or 1000 RPM? The answer that most people in this series have found is "not many."
2. How much more likely will your engine be to catastrophically fail if you rev it 500 or 1000 RPM higher for 8 hours at a time? The answer most people have found in this series is "very."

Even an improvement of 5 seconds a lap (which is unlikely) doesn't mean shit when you blow up after 2 hours and spend the rest of the day swapping motors. This is not HPDE. This is not time trial. Your car will not have a chance to cool down after 30 minutes. Endurance racing is the art of accidentally finding new and exciting ways to destroy your car that you never saw coming. All these suggestions for improving cooling and oiling are necessary to reduce the chance of your motor blowing up even if you don't rev the piss out of it.

There are many much safer (i.e. non-destructive) ways to improve your average lap time than revving the engine to the moon. The low-hanging fruits are mostly in team organization (eg. streamlining pit stops so you're not fumbling around taking 20 minutes to fill up and swap drivers, having a well-stocked and organized paddock so you don't take 2 hours to solve a problem you could have solved in 30 minutes, drilling into your drivers to not push the envelope for 2 hours so they don't make mistakes and lose time in the penalty box).

Your first race will be hard enough. Don't learn the hard way that a slow car on the track makes way more laps than a fast car in the pits.