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On throttle by wire cars you are asking for a certain throttle position. The ecu decides what throttle position it will give you. Traction control comes to mind. You maybe commanding WOT but too much steering angle, wheel spin or yaw and the computer(s) may decide the throttle should not be wide open.
About how tall is the person in the white helmet in the passenger seat?
No idea, we did not measure our passengers
I am 6 foot 3 and very slim. The top of my helmet to the top of the roll bar is about 2 inches with the Sparco Evo 2 on custom seat brackets. Stock seat I had about a half inch. Moti is about 5-8 and slim, he could barely see over the dash in the Sparco. The gt3 is above the plane of the soft top. So if you fit in the car with a soft top you will have extra room with the gt3 and any future hard top that fits the gt3.
), a foam windscreen, and some velcro (or zipties) should help dramatically. The lead on the microphone is long enough to where you can easily fish it into the passenger foot well and get it out of the wind.
If you want, I can edit and do an A/B comparison for you.
A hardtop doesn't solve the GoPro having a shitty mic, but you know what you're doing.
We get sound that's good enough for our purposes with the NA and NB track cars with hard tops. No doubt better sound available with additional hardware or setup. Now when we start making videos from OGK with 400whp and no windshield, we'll need to upgrade.
On throttle by wire cars you are asking for a certain throttle position. The ecu decides what throttle position it will give you. Traction control comes to mind. You maybe commanding WOT but too much steering angle, wheel spin or yaw and the computer(s) may decide the throttle should not be wide open.
(replying late)
The throttle-by-wire cars I've looked at (mostly Audi products) don't map the pedal position to a throttle position request -- they map it to a torque request. i.e., 10% throttle pedal means 10% of max torque. It's then up to the ECU how to best meet that torque request using whatever means are available to it. This is particularly useful on a turbo car, because if you're currently off-boost, the ECU can take the physical throttle to WOT for a little while to spool the turbo up and then back it down.
But yes, throttle-by-wire makes traction control, cruise control, launch control, etc work a lot better as well.
Finally got it back to the dyno after switching back to gas. Mathew wasn't available so he just emailed us a safe baseline tune he had on file. ECUtek will have their tuning suite available in a few weeks. We'll start tuning ourselves and continue development. No idea what the SAG 2.0 is capable of. It's a whole new realm for us. A few salient points:
Bore 83.5mm, same as a BP 1.8
Stroke is 91.2mm (BP is 85.0mm)
Rod ratio of SAG 2.0 is 1.70!
For reference:
BP is 1.56
B6 is 1.59
K20A2 1.62 (86mm stroke)
That's really high, particularly for such an undersquare engine. So it should rev like mad right? Well, no. High revs require a head that breathes. The PE-VPS head has small ports. Really small, crazy high velocity ports.
Peak head CFM stock with stock cams
174 CFM BP05 (NA8)
204 CFM BP4W, BP6D (NB)
157 CFM PE-VPS (ND)
We ran the flow bench way out to 3mm past OEM lift on the stock ND cams and as expected, flow didn't improve much. This points to a very thoroughly developed head, cam grind and ECU mapping. It works exceptionally well, truly world class in it's intended usage regime. Outside of that (trackday bro!), it's going to take some creativity to find big N/A power.
So why the really high rod ratio? Detonation resistance, that's why. Chambers that build pressure rapidly near TDC (low rod ratio) are more prone to uncontrolled hot sparky things happening. In a high rod ratio engine, the piston zips towards TDC then slows down, chills out and spends some time with it's bros, the DI and plug. They sit down and have a nice controlled combustion event. In the past, this relatively slow kernel growth and flame front propagation hurt low speed torque. With advanced multi injection pulse per evolution DI and continuously variable cam timing (atkinson/de-atkinson), OEM's can actually make what is effectively a variable compression ratio engine and control heat in ways that were not possible 10 years ago.
OEM rods are, ah dainty. We're not yet sure how much boost they'll accept before they wilt. Journals, yeah they're small too. Low friction means less heat wasted means less fuel burned.
So the bitchin rod ratio and acceptable stroke means we could theoretically spin an SAG 2.0 pretty high and still have mean and peak piston speeds in acceptable ranges. We tore an SAG 2.0 down a few months back and are slowly planning our first N/A build with some custom internal bits. Fun stuff. We'll be learning more as the months tick by.
Hard to read, sorry. 153whp, 146tq on 91. Tune, GCC header, metal cat, 2.5" exhaust. Otherwise 100% stock.
10-08-2015, 03:51 PM
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