How high can you go?
 

Alright I know I will catch flack for this one but whatever. I wanted to start this thread for those of us who want to rev the piss out of our beloved engines.

Yes, I know they are undersquare but there are other engines out there that are undersquare and still perform at High revs.

Yes, I know we don't produce loads of power at the top end but we could.

I just want to gather some information on what has been done to safely push the rev threshold. I would like to know what type of modifications you have made that have allowed you to safely achieve a much higher rev than the 7k I see on my 1.8 tach. If you have blueprinted your engine your input would be much appreciated.

FYI - I am not focusing on what can be done on a stock motor. So please don't limit this thread based on this factor.

oil gears + valve springs.

I have my billet oil pump gears waiting to go in. As for the cause of the grenading oil pump gears, am I correct in my understanding that this usually occurs when the crank flexes at high revs? Should upgraded main caps be considered to further prevent this flex from occurring?

Nobody "knows" why OP gears break. People speculate it's from crank flex. But nobody really knows. Kinda like everybody speculates there's a flow problem with our fuel rails so everyone "upgrades" to a dual feed...

Anyways, here's some of the possibilities that cause OP gears to shatter.

It could be crank flex from too much HP/to many revs.
It could be harmonics causing crank flex.
Or both.
It could be from having a worn out/faulty harmonic balancer.
It could be the factory harmonic balancer doesn't damp certain harmonics at 7K+ RPMs
It could be from the pump is literally "pumping too much" and not being able to bypass enough oil at really high RPMs and the gears shatter from trying to, effectively, compress a liquid. FWIW, 01+ oil pumps have two bypasses... And 0 reported OP gear failures to my knowledge...

Show me an undersquare 1.8ish I4 that pumps out the power at high revs.

Our engines have a really shitty head for making high RPM power. That's most of the problem. But it's by design as the engine wasn't designed to spin any higher.

Only real way to "fix" anything is to get the bore up and open up the combustion chambers so that the head can breathe at higher RPMs. Raising the floor in the cylinder head would help a lot too. And a well designed intake manifold to feed the new runners.

You can drop a lot of money on "parts" and it will spin faster with somewhat better reliability, but you won't be making any power.

Honda B18c (in the acura integra (including type R))

# Redline: 8100 RPM
# Bore: 81 mm (3.189 in)
# Stroke: 87.2 mm (3.433 in)
# Rod Length: 137.9 mm (5.429 in)
# Rod/Stroke Ratio: 1.58

That is interesting. I don't know anything about the 01+ engines. Could it be possible to retrofit a BP-Z3 oilpump onto a BP-4W. I know their gears are different in size.

That's a honda. The head is, uh, a lot better than ours. But if I had to guess that's an aluminum block w/ sleeves. So that in itself has its own limitations. Undersquare engines that make power are few and far between. It's NOT the recipe for a smooth high RPM machine.

01+ motors have the same block and crank, so the pumps should interchange. But I have no real world experience with them to confirm/deny this. Also have no proof that swapping them would be beneficial.

by what do you mean?!

http://www.m2race.com/images/Sport%2...8%20intake.jpg

vs.

http://www.boostedmiata.com/projects...l/IMG_6332.JPG

Take a stock B16 head and flow bench it. You'll find it flows higher numbers than our stock head. By that, is what I mean. It is a much more performance oriented part. Reduced ss radius, straighter ports, better bowl work, angled valves that better match the angles of the ports so air doesn't have to turn as much, which, as a side benefit, drastically reduces shrouding, further improving flow and turbulence in the cylinders, vtec so it can switch to a hotter cam at higher RPMs. There's A LOT that makes the honda's head better than ours. Isn't this obvious? It's pretty much THE reason hondas became so popular. Because they have potential. If they had just used an iron block, they would have made a killer engine for 80's technology.

did you not see the pictures? i know this....

I was wondering... Yes I saw the pics. Speaking of quiet mufflers, have you ever heard one of Summit's 3" "turbo muffler"? My Magnaflow is way too loud. Driving me insane.

I had a Summit Racing Turbo Muffler on my Altima for the longest time :)


install your turbo and it wont be loud anymore.

This thread is useless, if you want to spin it faster but don't want it to break its going to cost money, then there is the problem of making fuck all for power unless you have some More money...All in all its not worth the silly grin on your face when the tach bottoms out.

Just buy a honda, or drive your gf's swapped ek ;) 9k ftw.

Is this the port job you did on your 1.6?

looks like the honda head.

how much of the metal in the Miata's head can be removed before you hit a nono?

Also another honda example on the oil pump topic...

there is a difference between the B18b (non-vtec) oil pumps and the B16, B18c and B18c5 oil pumps. I dont know off-hand what the difference is but there is also a big difference in the water pumps and how much they flow at high rpms.

Also the higher revving engines have a different rod/stroke ratio which i think is the most important aspect. Again, I dont know the specifics but I can remember reading about this.

Also consider the high-revving vtec motors switch to higher duration cam lobes at the higher rpms, this is why it cracks when you hit vtec. That is how they make the power up high.

Our engines just plain aren't meant to rev that high and never will be. Honda engines are vastly different.

Edit:

If anyone is in the mood for an interesting read on the difference between low revving and high revving water/oil pumps, here is a good article from team-integra.net

http://www.team-integra.net/forum/di...g+Common+Topic

That might clear some things up.

mmmmmmmm. torque drop!

https://www.miataturbo.net/forum/att...geot_run1b.jpg

This is the Dyno Sheet on a naturally aspirated built '97 1.8L block married to a '99 head. 1mm oversized intake and exhaust valves, head work, 1mm over-bore pistons, opened oil journals, balanced/knife-edged crank/flywheel/pressure-plate. - About the only thing not done was installing stiffer valve springs to prevent float about 7500 rpm.

Please note the definite downturn in torque above 5500 rpm.

- L

Do you think a different cam might help that?

I used to rev my stock sleeved, stock head, turbocharged to 600hp LS/VTEC 1.8 Engine to over 9500rpm with a set of Rods similar to our M-Tuned Miata Rods with a stock Oil Pump.

I've also seen 220 hp with almost all stock parts using a B20 Block/Type R head with aftermarket valve spring. This motor lived most of its like between 7000-9500rpm.

Honda motors are great!