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That's pretty quick, too. Congratulations. What fuel are you running? C16?
We did a 100-300 measurement yesterday: 15.05 seconds. That's all ***** out now. Fuel tank is almost 1/2 full. With a little bit of tail wind and/or almost empty fuel tank and/or cold weather we would break into the high 14s, but that's actually all this platform can do without further hardware changes - or at least all I can do.
We stop here and call it a day pushing these VTGs harder, before they melt off of the brackets
Have you logged EGT from the actual sensor on these runs?
Yes:
On a 100-200 run it stays below 900 degrees C, depending on when you start the run, 3-4 or 4th gear alone etc. Between 870-900 is the sensor data.
@300 km/h it's 960 to 985 degrees C, raising to a little shy over 1000 for a second when you are over 310 km/h, but it will go back down afterwards. This temperature hump is normal for this platform.
OBD data for 308 km/h as of yesterday shows 935 C.
1000 at 310 is pretty good at the turbine entry considering the temps you are running, that's with meth and 102 yes?
I was about to run mine a 1.45 bar at VMAX last weekend but the car infront was the last to run so I didn't get any data That's on standard 997 housings.
1000 at 310 is pretty good at the turbine entry considering the temps you are running, that's with meth and 102 yes?
I was about to run mine a 1.45 bar at VMAX last weekend but the car infront was the last to run so I didn't get any data That's on standard 997 housings.
Rick
102 and meth, correct. The car is running 2 bar of boost and there is a lot of pressure on the exhaust side. GT2 housings, but my personal opinion is that it doesn't matter much.
We are running about 80% spray at the moment. The pump supply is not good enough @160 PSI. We may upgrade the WMI pump for this reason and this would bring down temperature quite a bit.
IAT on the last run start at 24 degrees C and raise to 41 @ 305. km/h
I think with 98 and meth it would be just a little too risky EGT wise for 300kph+ . I will get round to trying 109 at some point but lost a lot of testing time this weekend so I'm behind on where i want to be. Ehat timing are you seeing?
187 at 1.1 bar mate, it was HOT and apparently 30mph headwind. I don't know about that but it was certainly blowy and it was very welcome on a baking runway!
We stop here and call it a day pushing these VTGs harder, before they melt off of the brackets
What shall I say: I lied, lol
60-100 is still in the 2.5 range, but now in 4th instead of 3rd gear
60-130 5,15 is not too shabby in 4th
and 4.4 seconds in 4th for 100-200 km/h is pretty good.
Everything is uphill as you may have noticed. The real numbers we were chasing were these (all above are just extracts of these 2 runs):
14.5 seconds for 100-300 km/h is not slow for a VTG based 997 I would say. 2 runs consecutively on the same Autobahn section.
I don't say I call it a day this time. I might get back to this project next year but for more gains I might need to call up Sam for some new turbos.These are squeezed out now.
60-100 is still in the 2.5 range, but now in 4th instead of 3rd gear
60-130 5,15 is not too shabby in 4th
and 4.4 seconds in 4th for 100-200 km/h is pretty good.
Everything is uphill as you may have noticed. The real numbers we were chasing were these (all above are just extracts of these 2 runs):
14.5 seconds for 100-300 km/h is not slow for a VTG based 997 I would say. 2 runs consecutively on the same Autobahn section.
I don't say I call it a day this time. I might get back to this project next year but for more gains I might need to call up Sam for some new turbos.These are squeezed out now.
Congrats, best times I ever seen with VTGs.
Especially 14.5' at 100-300 is very solid time, and you are not catless if I'm right!
Impressive times,
It shows me the efficience of high octane and WMI with VTGs, my 66mm VTG setup with straight euro 98 gas didn't achieved better than 20' at 100-300, even catless.
Boost was 1.45 tappering to 1.30Bar and angle was <20° at top end, the car dynoed 670hp/900Nm on a Superflow Wyndin.
Impressive times,
It shows me the efficience of high octane and WMI with VTGs, my 66mm VTG setup with straight euro 98 gas didn't achieved better than 20' at 100-300, even catless.
Boost was 1.45 tappering to 1.30Bar and angle was <20° at top end, the car dynoed 670hp/900Nm on a Superflow Wyndin.
That's correct: a lot of the performance comes from precise temperature control to prevent knocking. 102 octane pump fuel is mandatory and 50/50 WMI covers a lot of the remaining problems. It took quite a lot of effort and measurements, but now now the system is stable and it does run after run within 1/10s or even 1/100s of a second.
Your 100-200 time on 98 octane at that boost level is about what you can get out of that system. It actually is not bad at that level. I guess the boost taper down was because you lost ignition at higher level of boost and at the same time EGT raised which in turn caused more knock because of the high VTG turbo backpressure and the flowback of hot exhaust gases.
That's correct: a lot of the performance comes from precise temperature control to prevent knocking. 102 octane pump fuel is mandatory and 50/50 WMI covers a lot of the remaining problems. It took quite a lot of effort and measurements, but now now the system is stable and it does run after run within 1/10s or even 1/100s of a second.
Your 100-200 time on 98 octane at that boost level is about what you can get out of that system. It actually is not bad at that level. I guess the boost taper down was because you lost ignition at higher level of boost and at the same time EGT raised which in turn caused more knock because of the high VTG turbo backpressure and the flowback of hot exhaust gases.
Sure the temperature control is the key, overall with vtgs.
Yes the 20' at 100-300 seemed to me the best time we can get with straight 98 pumpgas.
But the boost did not taper because ECU pulling, if we mapped 1.45 until redline the ECU reduced boost and angle so much the 100-300 was about 25 to 27' (but the 100-200 was 5.5').
We mapped ourselves the tappering at top end in order to prevent the ECU pulling and achieved better results at long pulls, but 100-200 was 6'.
I had to make the choice between short and long pulls mapping.
Being a bit anxious with WMI especially methanol mixed and 102 octane gas being not available here I run for now E85 which provides also excellent knocking resistance and temperature control.
06-27-2018, 03:24 PM
That's on standard 997 housings.
