Got some questions for the gurus here, and I am kicking myself for not having asked them earlier.

If you build up a 2.0L block to support higher rev limits, somewhere between 9000 and 10000 rpm, then how do the items attached to the accessory drive belt fare?

- Can the oil pump handle sustained operation at 9000 or more rpms?
- AC?
- Alternator?
- anything else on the belt?

- Can I substitute "better" replacements (esp. oil pump and alternator)

- Can I use an underdrive pulley? (a'la the older SHO's)

After reading about the disastrous engine (oil pump?) failure of the Evo in the USCC shootout, I'd like to make sure that this type of thing won't start happening on high rpm 4G63 in road racing conditions... (read: my Evo).

l8r)

 

Bump

 

Pretty sure the oil pump isn't on the 'accessory' belt Yes there are underdrive pulleys available. I havent heard of any failures of the alternator at extremely high RPM's and most people that have motors that spin to 10k dont have the AC anymore. The AC is driven by a clutch so it would be fine I assume. Alternators are generally tested at a MUCH higher RPM than the motor could ever spin so I doubt its a problem.

 

Ah, umm yeah, doh! I should have listed that as a separate bullet.

My main concern is that after the rather spectactular failure of an Evo oil pump on a road course at high rpms, I'm trying to figure out what, if any, the consensus is on how much is too much for the stock oil pump.

l8r)

 

10,000 you are insane..

 

Yes you could build the motor to spin at 10k and yes i have heard some problems with the oil pump failing at those high RPMs. I never bothered to figure out how to replace them or build them stronger but if you honestly plan on going past 8.75k than I would recommend looking into it.

Pretty sure there is a number of Evo's revving in the range of 9-10k so dont think it is impossible. My guess is the AMS's revs there, Curt Browns, etc...

 

Yes, all of the mentioned cars (including mine) rev past 9000rpms ... however the AMS car and Curt's car both only do it for 1/4 mile purposes. Mine needs to be able to perform for 25-40 minutes at a time... Granted it won't be at redline all the time, but you figure it will be near redline 3 or 4 times per lap.

The bottom line is that if I don't find satisfactory answers/solutions to my questions, then I may have to rethink the engine build and go with a stroker instead of the higher revving 2.0L.

l8r)

 

Someone needs to incorporate a ball bearing system into the pump gear. That should solve the issue.

 

My car and its harmonics, are cracking my stuff apart! First the AC aluminum hose, then the AC bracket, Then the Alternator bracket! I shift around 4-5 K, get the car up to a high RPM, and keep it in that gear and coast. I do take it up to the red-line on occasion, and I have also ripped 2 serpintine belts in the process. I plan on taking the AC off and balancing it! When I went to putnam for 2 hours on the track, the Revs were up, and I had to retire, as the Serpintine belt was shredding!

 

I forgot to mention the Cracked oil pan from the higher RPM vibrations/harmonics. I would say you have to balance the engine, internals, and get poly bushings. I havent heard of an oilpump failure. Isolated case? when the RPM's get up there, the pulleys go back and forth, and slip the belt. (my case) I also forgot to mention, the bolts connecting my coil-packs, worked their way out on race day, 4 popped completely out, the rest were finger tight!
The higher ther RPM's, the more harmonics, the more cracks you will find. unless you can spin at 10K, without too much internal engine "Wobble". I want to do the same to my motor this winter!

 

For 1/4 mile racing I think 9500-10,000 rpms sounds feasible. Now for roadcourse racing I think its nuts and probably not necessary. What turbo are you planning on using? All big turbo Evos run very hot oil temps on a racecourse. Mine was over 300 degrees all the time, and closer to 325. The oil pump is driven off the front balance shaft drive, therefore there is nothing that I know of that can be modified. I would believe that high rpms, lateral g's and high oil temps can cause oil pressure problems. In order to rev that high you will need a completely balanced bottom end with matched piston, rods. The crank should also receive a full balancing up to 10,000 rpms. The head must be able to flow air up top, therefore expect to not build much power till about 5500-6000 rpms, no matter what turbo. The only turbos that will build power at those rpm levels are the big boys like GT35r and bigger. The valvetrain must also be ready for stiffer dual springs, lighter retainers etc. Good luck!

 

I'm running an AMS 3071 kit, supertech valvetrain, ross pistons, crower rods, no balance shaft. Current fuel cut is set at 9100 rpms, but with the current torque curve, the shift points are actually around 8200 rpms, which gives me a powerband of ~4200rpms to play with. The only time I would take the car past 8200rpms is on short straights where holding onto the current gear is better than shifting into the next gear...

l8r)

 

MAN, my car cries after 20 minutes of 7500rpm abuse...id hate to see what it did to me if i reved it to 8500 for 20 strait minutes.

and smokedmustang, you got one bad apple of an evo....i have never had any of those problems.

 

I would not be concerned with the oil pump at 9000rpm's.

More importantly, piston speed, and cam speed.
You would have to get solid lifter, and much stiffer valve springs, maybe even double valve springs.

Piston speeds

Piston Acceleration
*
Gmax = ((N^2 x L)/2189) x (1 + 1/(2A))
Gmax is maximum piston acceleration, in feet per second squared
N is crankshaft speed, in RPM
L is stroke, in inches
A is the ratio of connecting rod length, between centers, to stroke
Piston Stroke Motion
S = R cos X + L cos Z
S = the distance piston wrist pin is from center of crankshaft
R = the radius of the crankshaft wrist pin
L = the length of the connecting rod
X = the angle of the wrist pin
Z = the angle of the connecting rod
or
sin X = R/L sin Z

As the speed increases, the harmonics change, this can cause all kinds of problems.
If you want to go at that RPM, you have to try to lighten the rotating mass as much as possible, with light weight pistons, rods, and balance everything.

Find out exactly what the 10,000 race cars do, and copy it.

BTW, if you are going to have a 10,000 RPM car, you will be running a dry sump system for oil.

The last engine I built, we went from a 7200rpm redline, to a 9200rpm redline. It took a lot of work and $$ to make it reliable and last more then a few runs.