Anyone run locked out VCT?

[bauern]

I'm inferring gen2 coyote openning/closing events based on the above chart from gen1 events as the cam duration @ .050 lift are the same:

Max retard:
IVO: 16.5* BTDC
IVC: 14.5* ABDC
EVO: 1.5* ABDC
EVC: 32.5* ATDC

Parked:
IVO: 3.5* ATDC
IVC: 34.5* ABDC
EVO: 48.5* BBDC
EVC: 17.5* BTDC

Max advance:
IVO: 53.5* ATDC
IVC: 84.5* ABDC

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[honeybadger]

Alright - data is in! It's not great, but it's not terrible!

So to get it out of the way, apologies for the poor format for comparing. The reality is these were done 2 years apart, on 2 different dynos, with 2 different tuners. I just didn't have the ability to control these variables, unfortunately.

So this top image is for the motor with VCT. Runs breakdown as E85(top), VP100 (middle), and 93 tunes (bottom) I had for your average track day. These were quite de-tuned and conservative.

This image is from today with the cams locked out at 120 for the exhaust and 112 for the intakes.

As you can (sort of) see, the big differences are in the drop off at the very top and between 3,500 and 5,500. With VCT, we have about 360ish hp around 4,500. Without VCT, we're only around 320ish. Pretty big loss. And then there's the huge torque loss under 5k. Ha! But 5700-7600 is pretty similar. I'll keep reviewing and digging and share more.

Most of this is not a surprise. The main surprise was the dip up top. Notice how VCT graph doesn't climb above 7600, but it stay level. Comparatively the VCT-delete motor falls off a decent amount from 7,500-8k. The tuner felt that we could move that up with some adjustment on the cams. I told Tim to optimize power where the stock cams make power and that's what I think we're seeing. Aftermarket cams could help fix this.

Hot takeaway: I am quite pleased how smooth the the pulls are given the lockouts. I expected a much bigger hitch around 5-6k. It's quite smooth. I'll be very curious to see what this motor feels like on track. Objectively it's pretty clearly worse, but my limited driving so far makes it feel pretty fun. We'll see what happens on Saturday on track

 

[jmn444]

yeah seems like the vct torque curve would be preferable since there's not much gain anywhere, but def let us know how it turns out on track.

 

[honeybadger]

yeah seems like the vct torque curve would be preferable since there's not much gain anywhere, but def let us know how it turns out on track.

For sure. There was never going to be a gain without changing the cam. Out best hope was matching the VCT-curve in our ideal powerband - which I think we mostly did in the 5600-7600 area. I'd be pretty curious to explore some cams that add more power north of 7500

 

[Cobra Jet]

Alright - data is in! It's not great, but it's not terrible!

So to get it out of the way, apologies for the poor format for comparing. The reality is these were done 2 years apart, on 2 different dynos, with 2 different tuners. I just didn't have the ability to control these variables, unfortunately.

So this top image is for the motor with VCT. Runs breakdown as E85(top), VP100 (middle), and 93 tunes (bottom) I had for your average track day. These were quite de-tuned and conservative.

This image is from today with the cams locked out at 120 for the exhaust and 112 for the intakes.

As you can (sort of) see, the big differences are in the drop off at the very top and between 3,500 and 5,500. With VCT, we have about 360ish hp around 4,500. Without VCT, we're only around 320ish. Pretty big loss. And then there's the huge torque loss under 5k. Ha! But 5700-7600 is pretty similar. I'll keep reviewing and digging and share more.

Most of this is not a surprise. The main surprise was the dip up top. Notice how VCT graph doesn't climb above 7600, but it stay level. Comparatively the VCT-delete motor falls off a decent amount from 7,500-8k. The tuner felt that we could move that up with some adjustment on the cams. I told Tim to optimize power where the stock cams make power and that's what I think we're seeing. Aftermarket cams could help fix this.

Hot takeaway: I am quite pleased how smooth the the pulls are given the lockouts. I expected a much bigger hitch around 5-6k. It's quite smooth. I'll be very curious to see what this motor feels like on track. Objectively it's pretty clearly worse, but my limited driving so far makes it feel pretty fun. We'll see what happens on Saturday on track

@honeybadger

Just curious how it ran at the track (if you were ever able to get it there after your above post)?

 

[honeybadger]

@honeybadger

Just curious how it ran at the track (if you were ever able to get it there after your above post)?

Howdy!

Ran great! It's an interesting driving experience. I'm able to put power down much better in lower gears giving the smoother power build up. When I stuck with 3rd gear, I didn't notice any major areas where the car was slower - it still ran 2:28s and 2:29s on worn out tires. The new power curve feels very much like the difference between a Coyote and a Voodoo, just more Voodoo. So far, I am a huge fan.

(2) downsides at the moment

1. It's a bit temperamental below 2k. A lot easier to stall it in the pits and you do need a bit more RPM to get going

2. I'm only generating between 14-18 inches of vacuum and got a hard pedal a couple of times. I've put in a vacuum canister and had a tune revision to see if that helps. We'll see

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