High RPM NA1 Engine?

[BATMANs]

I'm sure most of you have seen my engine build "co-thread".

I used lighter pistons and valves and while the car was tuned we set the redline to 9kRPMs on the AEM EMS rev limiter and took it all the way up with no issues.

Of course I took that back down to 8200RPMs to be "safe". for the long term.

 

[nismor32gtr]

The nsx-r engine has a little more internal work. Light weight valve train and lower end And blue printed with micro polishing and 0'ed balanced crank.

 

[Honcho]

Bats is on the right track and you should talk to him- he's done his homework on the C30 internals. Superlight valves, stronger springs, and lightweight forged pistons. Your Ti rods should be ok. As Billy pointed out, power drops off after 8,000 on the stock cams, so you need to change your cam to make power in the 9,000+ range. That's why I suggested Toda Spec C- they are designed for optimal breathing at that rpm range for the Super GT engines. The SOS/Web cams might also work- you should ask Chris. ITB's are a must and the SOS kit is nice. I also think AEM Infinity is a perfect ECU solution for this build. Since you are in Japan, the HKS F-con is a great option too, since there is competent tuning available. Also consider RDX fuel injectors for this build.

 

[nismor32gtr]

Yes I agree. I think head porting and light weight C32B valves with bigger cams are a must along with micro polishing and perfect crank balancing. Is there any way to shorten the stroke further? I'm guessing it would take a custom crank to get that.

 

[Honcho]

Yes I agree. I think head porting and light weight C32B valves with bigger cams are a must along with micro polishing and perfect crank balancing. Is there any way to shorten the stroke further? I'm guessing it would take a custom crank to get that.

Custom crank and that is $$$$$.

 

[dmscrx]

Yes I agree. I think head porting and light weight C32B valves with bigger cams are a must along with micro polishing and perfect crank balancing. Is there any way to shorten the stroke further? I'm guessing it would take a custom crank to get that.

There is no need to reduce the stroke more than it already is. It is plenty short enough to keep piston speeds/internal loads in check with aftermarket parts; even at 11k rpm.

 

[nismor32gtr]

I just want a reliable 10k. There's a engine for sale here on an auction for $2000 I might pick up and start slowly porting the heads on and working on a build.

 

[JD Cross]

I just want a reliable 10k. There's a engine for sale here on an auction for $2000 I might pick up and start slowly porting the heads on and working on a build.

You mentioned previously that the 2002+ NSX-R engine made power to 10,000 rpm.
Do you know where you found that information?

 

[dirtbag]

Any thoughts on the Hartley v8? 2.4L 400 hp @ 10,000 rpm....

I've always wanted one of those motors to toss into a mid-engine vehicle.
I believe they've pretty much reworked the entire design:
+ Reduced the displacement to 2.0L 400hp@~13,000 rpms 160ft/lbs @11,000rpms.
+ 175lbs weight
+ low profile sump
+ flat-plane crank

It's a beautiful engine. http://www.h1v8.com/web-page.html

 

[nismor32gtr]

I've always wanted one of those motors to toss into a mid-engine vehicle.
I believe they've pretty much reworked the entire design:
+ Reduced the displacement to 2.0L 400hp@~13,000 rpms 160ft/lbs @11,000rpms.
+ 175lbs weight
+ low profile sump
+ flat-plane crank

It's a beautiful engine. http://www.h1v8.com/web-page.html

Yeah but they cost more then a mugen MF308 so it's not an option for me

- - - Updated - - -

You mentioned previously that the 2002+ NSX-R engine made power to 10,000 rpm.
Do you know where you found that information?

Ill have to look I know it's from a Japanese nsx group page. The guys were talking about it and posted a link. There are some nsx-r oem speedos that have a 10k redline

 

[JD Cross]

Ill have to look I know it's from a Japanese nsx group page. The guys were talking about it and posted a link. There are some nsx-r oem speedos that have a 10k redline

Thank you. Would like to know the source of your info.
Do you have a pic of an NSX-R tachometer showing a 10 k redline?

 

[mr_goat]

Inspiration

Hi,

I think this topic is interesting. The technology in the C-series engine can be directly traced back to Hondas F1 engine program in the 80's which for the turbo era culminated in the reliable and superior 1.5L 80 degree RA168E twin-turbo V6 engine, powering both the Lotus team and the McLaren team in '88.







The engine produced around 670 hp depending on driver setting at 12 500 rpm/2.5 bar boost on toluene based fuel and could survive trips to 14 000 rpm reliably. Remember F1 engine valve trains back then were springloaded, just like our C-series. Although not as powerful as it's predecessors used in '86 and '87 it was more efficient as imposed by the fuel limitations turbocharged cars suffered from. As it was a proprietary race engine, the usable torque and power curve was optimized for WOT and was in the range of 7000 and 13 000 rpm. Even though very similar to the C-series, notable main differences to the C-series are a few:

• Cast iron block vs aluminium
• Turbocharged vs N/A
• Smaller bore and significantly shorter stroke (79 mm x 50.8 mm versus 90/93 mm x 78 mm) displacing a total of 1494 cc (although by the then racing standards being a fairly long stroke)
• 457 ps/liter displacement vs about 90 ps/liter displacement (!)
• Unusual 80 degree V-angle
• Dry sump
• Compression ratio 9.4 vs 10.2
• Narrow valve angle (32 degrees) and almost flat piston heads

Read the SAE paper on this engine for details of it's construction: http://www.k20a.org/upload/HondaRA168EEngine.pdf
I also strongly recommend anyone interested in this F1 era and specifically the Honda F1 technology powered teams to read this book which can be found on amazon:



Take a look at those beefy internals (and see the similarities to the C-series!):



And finally, the epic footage of the RA168E in action at the Monaco Grand Prix in '88 with Ayrton Senna behind the wheel, just listen to that masterpiece:

It would be really interesting to see if anyone tries a short stroke route of the C-series. Would sound awesome and probably perform excellently in race situations but would probably be a little frustrating on the street due to the short stroke and lack of torque in the lower revs. Turbocharging would be almost mandatory in order to provide any kind of usable power. Turbo lag would probably no be a problem at > 7000 rpm

 

[nismor32gtr]

well next trip down to tokyo ill be talking to Mugen and spoon more. I am starting to get some good honda connections and next year my car will be in the new Japanese NSX magazine. I would have been in it back in May but i could not get out of work and no one i trusted to drive it the 2 hours to Morioka to my buddys shop to do the photo shoot for the magazine.

 

[Levworks]

Has anyone looked into how big the Intake valve ports can be made with the use of a custom valve?

High RPM means an exponentially higher mechanical friction induced loss.

The positive pressure mentioned earlier by dmscrx is created by dynamic pressure which is expressed in the equation 1/2ρv^2 and is the pressure gained by induction scoops seen on race cars.

Although yes, ITB's would probably be the best, similar results can be achieved with a well designed intake manifold with shorter runners.

The oem induction system is a very well designed system but it is designed around the desired peak torque location honda chose. To achieve higher power levels at the increased RPM band, the balance of wave dynamics and inlet friction need to be designed appropriately. There are advanced equations that can get you within x percent of the setup that you desire.

In short, start by looking into the inlet system and design from there. Good Luck.

 

[stuntman]

Positive pressure is possible in a properly designed intake for a single throttle body manifold. It's not mutually exclusive for ITBs (which require a proper air-tight airbox, rather than open trumpets like most people run).

I'm not sure if the NSX has a pronounced 'peak' that Honda designed for since the torque curve is extremely flat through the entire rev range....

 

[JD Cross]

I'm not sure if the NSX has a pronounced 'peak' that Honda designed for since the torque curve is extremely flat through the entire rev range....

Still waiting to hear back from nismor32gtr about the NSX-R engines that make power to 10,000 rpm and have a 10,000 rpm redline. This would suggest Honda made special cams, intake, heads, ECU, etc. for the R engine which would be news to most. If Honda didn't make anything special for the R-engines except race type blueprinting then how do they make power to 10 K rpm?
Nismor32gtr let's have your info source so we can learn about these Type-R engines!

 

[Levworks]

Honda knows and has known all about peaks, wave tuning, and broadening the torque curve for some time. I'm sure initially they had a peak goal then took measures to maximize that peak number throughout the range. Here is an example of the power influence wave dynamics has. I edited this seemingly stock dyno graph of an NSX to show you where each harmonic is influencing the inlet air and "boosting" power. You can see these 3 wave dynamic humps in most proper dyno graphs. To see the highest influence from wave dynamics in numbers you usually want to design your intake so the peak torque is between the 4th and 5th harmonic, and the peak power is between the 3rd and 3.5th just as a general rule of thumb. Of course it won't always play out like that but it is a good starting point and as mentioned before, Honda has been using the strength of wave dynamics for years in racing along with many other OEM's.

There is a lot more detail to these ideas I just figured I would lay out some general info so people may pursue it for themselves and have a bit more of an understanding of what is going on. I do not know the exact measures Honda took to design this engine or intake system I just have been educated in the process in which a lot of oem and race engine designers use to layout the beginning of an engine package.

For anyone that wants to learn more about this I suggest picking up "Internal Combustion Engine Fundamentals" by Heywood.

 

[stuntman]

Check out the article I did on MotoIQ:

http://www.motoiq.com/MagazineArtic...est-A-Ported-Intake-Manifold-and-Headers.aspx

If you look at the Dyno graphs on Page 2 & 4, you'll see that even gutting the VVIS plates and significantly modifying the manifold itself virtually does not change the 3rd & 4th harmonic humps at ~5,500rpm and ~6,500rpm, while the removal of the VVIS plates does significantly impact the overall torque in the 5th harmonic at ~4,500rpm.

In a stock to moderately modified NSX, peak power seems to be around 7,500rpm which is well after you start to see a nose over and drop in the torque curve at 7,000rpm. The goal for an NA car would be to increase the torque above 7,000rpm and keep it flatter to make even more power.

Anyone with ITBs have the WinPep Dynojet run file from their dyno pull?

 

[robbiedawg]

just throwing this in here,our local nsx mechanic,the late steve gooding who was factory trained on nsx's told me the stock motor could easily handle 9000 rpm.

 

[JD Cross]

Check out the article I did on MotoIQ:http://www.motoiq.com/MagazineArtic...hose a short tube design and not a long tube?

 

[Levworks]

What changes in wave dynamics were you expecting to see from these changes? Wave dynamics are mostly altered by runner length and intake port size. Solid article, out of curiosity why do you think the removal of the vvis plate resulted in more power?

 

[stuntman]

Price, Packaging, and Performance.

The NA2 "Short" headers have less material, are easier and less expensive to manufacture, are easier to package with more room for the collector next to the block and only one pipe going under the oil pan, and most long tubes with more expensive merge collectors don't make much more power than the NA2's stock headers. That combined with Japan's HP gentlemen's agreement means there really is no reason to have made long tubes from the factory.

 

[JD Cross]

Price, Packaging, and Performance. The NA2 "Short" headers have less material, are easier and less expensive to manufacture, are easier to package with more room for the collector next to the block and only one pipe going under the oil pan, and most long tubes with more expensive merge collectors don't make much more power than the NA2's stock headers. That combined with Japan's HP gentlemen's agreement means there really is no reason to have made long tubes from the factory.

Thanks Billy
It sounds like the long tube headers are still better than the short tube factory units.

Nismor32gtr hasn't reported back on the 10,000 rpm OEM type-r engines he heard about in Japan.
From your experience are you aware of a factory 10,000 rpm version of the NSX engine?

From what I've read, to make power up to 10,000 the engine would need quite a bit of modification.
If these engines exist I would think you would be able to buy these performance parts from Honda.

 

[greenberet]

I also really like driving turbo cars because they are challenging.

Audi is testing a prototype 3.0 liter V6 turbo for use in street cars that has an electric motor attached to the turbo shaft. With that, they can spool up the turbo as soon as you touch the gas pedal, abolishing turbo lag. You could use the electric motor as a generator as well, having it generate electricity like in current F1 cars. If the turbo is electrically operated, why not separate the intake from the exhaust turbine, make both electrically operated with no shaft connecting the two and design more efficient intake and exhaust piping.

In the future, turbo lag and the associated challenge of modulating the power delivery will probably be seen as the side effect of stone-age turbo systems. A lag-free turbo that captures unused energy from the exhaust sounds good. In the meantime, give me n/a!

 

[jwmelvin]

If the turbo is electrically operated, why not separate the intake from the exhaust turbine, make both electrically operated with no shaft connecting the two and design more efficient intake and exhaust piping.

A straight shaft is a pretty efficient way to transfer power between two spinning assemblies. Unless there is a big benefit to them spinning at different speeds or to the change in flow layout, I suspect you would lose too much in the mechanical-electrical-mechanical conversion and transmission.

It was interesting to see Mercedes suffer a couple races ago when they lost the electric-assist on their turbos. It's definitely an awesome setup although I wonder for a street car how much benefit it will give if you already have torque fill from electric drive motors. I suppose you could eliminate electric drive motors and have the same overall torque response. But there are other possible benefits such as torque vectoring.

All fairly far afield from a high-RPM naturally aspirated motor, but interesting.