^ furiously typed Blackberry post above should have read thus: Loose engine mounts, combined with unshielded CPS wires, combined with TDI literally touching the ECU wires a bit and presumably somehow increasing the amount of noise the CPS wires saw, caused the car to not rev over 3000rpm. Ended up being towed home.

I think the glitch problem is solvable by changing the engine mount fixings, shielding the CPS wires, and installing a new CPS. The overly lean AFR is solvable by fitting an AEM EMS.




Note the air filter now sits right on the intake manifold. I requested it to be moved from its original position for two reasons. Firstly, it was getting covered in muddy winter crud. Secondly, I'd heard that the F20C likes either a longer intake than is possible to fit in the engine bay, or an extremely short intake that means mounting the filter on the manifold. The intake length I had before was, in theory, not great for "pulses and stuff". There's no doubt it was great at hoovering up truly ambient air, though.


Engine hit the limiter at 8600rpm, probably caused by the CPS getting confused again.



Edit: I want props for my shoes.

 

Seems like you need to turn on the VTEC earlier.

 

Exhaust bung testing has revealed that the medium-quiet bung reduces power by up to 15hp between 7000 and 9000rpm. The most restrictive trackday-spec bung loses 20hp. Hmmph. The car will be staying at Torque Developments for a few days while they source an S2000 ECU body loom plug, then they'll see what they can do for it on the dyno. They've told me that the exhaust bungs will probably increase the chance of detonation, which in turn means that the amount of ignition advance they can add may be limited. We'll see. I doubt the car will make 225 with the bung after tuning. The expense continues.

Times like these I'd probably have to think very hard if someone made me a good offer for the car.

 

Edit: full throttle from 4000rpm only, so ignore what's going on below that.

Top line: no bung - approx 225hp at the hubs, around 12hp more than stock S2000.
Middle line: road-friendly bung - approx 213hp, same as stock S2000.
Bottom line: current trackday bung - around 205hp.

As I've said before, drivetrain losses should be comparable to an S2000.





I'm currently wondering whether it's worth looking into more advanced silencing options so that I can avoid using an exhaust bung in every day use. From the photo below, you can see that there's space to hang half a silencer along the length of the exhaust that's next to the PPF. Yes, a silencer that's only on one third of the circumference of the exhaust. I'm getting desperate. Also, I'm pretty sure the larger of the two silencers can be made at least an inch larger all around (ie 2" larger diameter) and probably an inch or two longer. I'll have to have a good look at it.
It kills me knowing that all the work I put in to designing what appears to be a very effective exhaust in terms of power production is being wasted by shoving a bung up it.

 

I think I might just be able to fit a significantly larger second silencer in. I can't view the car as it's still at Torque Developments, so all I'm going on in this photograph and very hazy memories of the space I have available around the existing silencer. Looks like an ovalised asymmetric design could work, and potentially double the volume of the existing silencer.

So, what you're looking at below is a professional CAD rendering of the proposed new exhaust design. Solidworks 2013? Catia V6? Pah. Paint freeware is surely the next big thing in automotive engineering.

 

 

I love Endyn. They're the only company I'm aware of (please speak up if you know of any others) who are doing 'proper' R&D on the F20C at the moment. The results are pretty impressive. Serious expense though. If I can afford to throw some more money at this engine in the future, it'll almost certainly be directed at a Rotrex system. More than double the horsepower, worry-free reliability, near-stock throttle response and a completely linear power delivery, for £5000, will be mighty tempting.

Endyn F20C development thread: ENDYN-URGE designs S2000 Street & Track Build - S2KI Honda S2000 Forums

Rotrex S2000 at the track sounding pretty good:

 

I talked to Larry for like an hour last week on Miata engines, we might do something in a few years.

 

Here's a link to an article that may be useful to those of you who are looking for some quantitative data on the volume level of different exhaust muffler systems:

Sounding Off: Grassroots Motorsports Magazine Articles

 

Owen, the car is pretty amazing.I like the effort you made to keep the stock suspension geometry little disappointed ,in the chassis modification for ground clearance.

On to what I need from you, I am looking for a front driveshaft yoke from a Ford Sierra, I have a Quaife Sierra dog ring transmission, and I would like to have a spare yolk to act as a transmission plug for the Telus shaft housing, so I don't have to drain the transmission every time I want to pull it out of the car, obviously cheap and used is best. do you think you could help a fellow turbomiata.net number from across the pond ?

 

No problem, I'll ask around this weekend and get back to you.

 

Thanks Owen

 

Car now runs a rear-exit exhaust. I couldn't keep the external noise down to a sociable level, so a rear center exit with a decent size muffler was used. Now that it's bungless and mapped, it makes reasonable power. We did some intake length testing on a dyno at Northampton Motorsports today with very interesting results. I'll post the graphs at the weekend. The car was also weighed, and came out lighter than I thought it would be considering the metalwork that's in it. With a 3/4 full tank, it came in at 1005kg. Not sure what that is in pounds I'm afraid, as I'm typing from my phone and so don't have my handy Anglo-American converter. Exciting Weight data will be posted with the exciting intake length data. I'm so hot for data right now.

 

That's great and a pretty good weight as well! It works out to 2216 lbs. by the way!

 

So what are you going to do with the hole in the side of your car now?

 

Thanks Mr bcrx7.
Richy, I guess I'll cover and paint it. I'm not really that fussed about it to be honest. If I ever sold the car I'd certainly tidy it up, but as it is, I'm trying to focus on how it drives.

 

"The Old One" (TOO), founder of Endyn, is a notorious bullshiter. Years ago he had a D16 Honda with am M62 on it that he claimed was making like 380hp. I think it had a damn FMU on it, lol.
Im sure he knows what hes doing, and I know hes got some engineers, but that doesnt change the fact that he has lied about numbers.

 

No set up work, 65kg/145lb driver and 3/4 tank of fuel. Fully trimmed interior. Lots of potential for improvement after corner weighting!

Figures in pounds:
Total 2361
LF 567.5 RF 629.5
LR 562 RR 602





Intake length testing: The car was tuned for the "short" intake. I asked the dyno operator to do another run with the short intake five minutes after the initial few short intake runs had been completed, to check for repeatability. It matched the initial runs to within 1 horsepower all the way across the rpm band, which I thought was impressive. So, the results are accurate enough for back to back testing.


The "short" intake can be seen further up the thread; it's just the filter attached directly to the intake manifold.
The "longer" intake looked like this:

Note that it's the same as the original intake I ran on the car, but flipped upside down so that the filter was not right in front of the fan.

The "longest" intake looked like this:


Results:
Power


Torque


FYI, I'm not a great believer in "corrected" figures. For what it's worth, the car made 214 at the wheels, which is 20hp more than the last F20C powered car they ran on this dyno.
Torque Developments seem to have done a good job with the tune. The AFR plot is impressively flat. However, the car sometimes stalls when hot, which is why I went to Northampton Motorsports to investigate. Sure enough, it stalled on the dyno when we got the conditions right. Turns out it's currently mapped super lean at idle, and before it stalled it went 'excessively' lean - i.e. it pulled out so much fuel that it died. So, this would have been a simple fix, but unfortunately the tuner normally tunes Omex and Emerald ECUs, and we couldn't get the AEM software to download successfully on to any of the NM laptops! So no tuning was performed. Ah well. Bit of a miscommunication between us when we were booking the session.
It will go back to NM in a couple of weeks. The hot stalling issue will be fixed, and the hard cut rev limit will be extended from 8800rpm to 9000rpm.

 

Hmm thats definitely interesting, i wonder what happened at redline on the middle intake there.