Check out this video of two trips down the front straight at Road America, the first is lap 6 and next is lap 7
I was taking it easy in my first session just getting used to the car. On lap 7 the car started to give me problems. I would describe it as slipping or misfiring. The engine would not rev past 8,000 RPM. I'm not letting off the throttle in this video, the car just won't go any faster. I went out for my second session and the car was great at the start but did the same thing after 6 laps.
I was getting oil temp of 165 and water temp of 125. When I discovered that I decided I was done for the day because the manual says not to exceed 130C for oil and 100C for water. I assumed my 2007 Radical dash is in C because that's what the manual references, but after some testing today I'm doubting that.
In this thread, Crit said his water and oil numbers don't even light up on his dash until they hit 45C https://radicalsportscarregistry.com/radicalforum/sr3-specific-discussions/is-it-normal-to-not-see-oil-temperature-on-a-first-gen-car/ My numbers first light up at 112 (which happens to be 44C), which would mean the water is boiling on the first reading if the dash was reading C. I measured the water reservoir with a kitchen thermometer and it measures 177F when the dash says 126 (which is 259F). If I shoot the aluminum parts of the coolant lines with an infrared thermometer they're almost identical in F to the number on the dash. So I think somehow despite the Gen 1 owners manual stating the dash temps are in C my dash is in F. I messaged the prior owner but he didn't respond. Maybe something was modified?
I did also feel the water pump when the power is on and it's running. If I disconnect the highest coolant hose water shoots out when the power switch is on and I can also see water swirling in the reservoir. If I turn the power switch off the water is silent.
I'll also note on earlier laps when the car was running fine the oil temp shows ~165 and water ~120.
My final point to add is that I had the engine out recently to have the transmission rebuilt so my first thought is something didn't get hooked back up correctly. I went back and looked at prior video however and the temps on my first outing with the car were the same as my day at Road America. I think I didn't experience this problem before because I couldn't push the car to 10,000 RPM with the transmission issue. This car is new to me so I have nothing to compare to.
Does anyone have any idea of what may be going on here? I plan to check the plugs tomorrow. I'm not sure what else to troubleshoot. Whatever problem I'm having only happens after the car has been running at load for around 15-20 minutes.
Reading through Hayabusa forums people point to a fuel pump/filter for this issue. I guess no harm in replacing it to rule that out. It stinks though that there's no way to really test it besides paying for a track day and maybe being done for the day after 20 minutes.
@gobble - good suggestion I think. Someone else will know for sure (I haven't driven my car yet... new to this too!), but I think if it's a fuel pressure problem you should be able to look at the data from the log (or the just look at the reading on the main dash screen while your driving) and make sure the fuel pressure is ~3 bar. I would expect a blocked fuel filter, or knackered fuel pump would see the pressure reading low....?
I've been corresponding with SBD Motorsport in the UK after talking with someone in NZ that I found on another forum who had the same problem. The ECU is mounted on the firewall close to the engine and apparently they've been known to fail when they get hot. SBD Motorsport sure seems to know a lot about the MBE engine management system. They will be sending me a newer version of the ECU with maps already loaded and also software and a diagnostic cable where I can download engine data and also have someone do a tune. Hopefully this fixes the problem. The guy in NZ replaced just about every fuel and spark related thing you could think of before connecting with SBD.
The fuel pump/filter seems like a logical culprit, but why only when hot? The ECU makes sense.
@gobble.... G'day - just interested in whether you got to the bottom of your problem??
I purchased the new upgraded ECU from SBD, and the car seems to run fine, but it's winter here so I haven't had the car on the track yet. I feel good though that this will fix the issue. SBD said this was a common issue with the older ECU.
