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S197 3V Fabman's build; How did we get here? Build Thread

3,826
3,167
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
I think you're a brilliant driver but your tach hasn't got a clue what's happening. Great driving with your engine at idle.
Thanks for the compliment.
I have much to learn still....hard to get the banked track/spool differential mentality outta me but I'm working on it.
I always wanna dive in too early and it hurts my exits.
 
522
658
Exp. Type
Time Attack
Exp. Level
Under 3 Years
SoCal
Here check this out....what do you think?
I would be thrilled if my rpm calc is wrong, the car behaves much better in 3rd than shifting up and down all the time.

Yeah, definitely screaming on the 3 straights leading up to corkscrew. Lap 4 made me pucker off the corkscrew - I swear you caught air on the way down!
 
3,826
3,167
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Yeah, definitely screaming on the 3 straights leading up to corkscrew. Lap 4 made me pucker off the corkscrew - I swear you caught air on the way down!
All that underbody is like a sail and lets me float to the ground...lol.
So what's your gut tell you about RPM? Am I pushing it here or don't worry?
 

Dave_W

Cones - not just for ice cream
272
268
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
Just for kicks, you might want to calculate the difference in net torque between holding the gear at that rpm and shifting up a gear. Could be that shifting puts you in a better part of the torque curve that makes up for the loss in torque multiplication from shifting. Or maybe not.
 
522
658
Exp. Type
Time Attack
Exp. Level
Under 3 Years
SoCal
All that underbody is like a sail and lets me float to the ground...lol.
So what's your gut tell you about RPM? Am I pushing it here or don't worry?

The MPH change from 8200 to 9000 is 11.4 mph, hitting 128.6 As short as those straights are, its not likely the speeds have increased that much.


Tire
25.6​
Rear Gear
4.10​
1st2nd3rd4th5th
T-56
2.66​
1.78​
1.30​
1.00​
0.80​
7900​
55.2​
82.4​
112.9​
146.7​
183.4​
8000​
55.9​
83.5​
114.3​
148.6​
185.8​
8100​
56.6​
84.5​
115.7​
150.5​
188.1​
8200​
57.3​
85.6​
117.2​
152.3​
190.4​
8300​
58.0​
86.6​
118.6​
154.2​
192.7​
8400​
58.7​
87.7​
120.0​
156.0​
195.0​
8500​
59.4​
88.7​
121.5​
157.9​
197.4​
8600​
60.1​
89.7​
122.9​
159.8​
199.7​
8700​
60.8​
90.8​
124.3​
161.6​
202.0​
8800​
61.5​
91.8​
125.7​
163.5​
204.3​
8900​
62.2​
92.9​
127.2​
165.3​
206.7​
9000​
62.9​
93.9​
128.6​
167.2​
209.0​
 

Dave_W

Cones - not just for ice cream
272
268
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
Just in case you aren't sick of my videos yet....here's the latest.
That tach needle is driving me crazy. You should email Autometer tech support with a link to the video. Maybe it's a bad unit.

It seems to "clean up" when you're full throttle, and be much worse when you lift. Crazy idea, but could you have tapped into an injector wire instead of a coil driver wire? Just thinking the bouncing could be due to injector duty cycle - it stops bouncing if the duty cycle gets over a certain percentage.
 
3,336
3,094
A lot of tachs have "flutter" at the end of their range. The first time I saw a tach hit 20K was a kart race in Jamaica. it just ceased to read over 1999. Would not feed back, couldn't download, nothing. all the RPMs around it were like 1990, 1996, 1890 so it was clear the tach couldn't handle the RPM. For some reason, finding a decent tach for an electronic ignition is almost impossible, Back in the day we ran mechanical drive tachs off the distributor for accuracy, but those days are gone.
1622553832351.png
 
3,826
3,167
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
I’m not really a tach watcher, in fact, I almost never look at the tach when I’m driving which is why I use the tattle tail variety. I just need to know if I am pushing the engine too far. The math on the mph to rpm calculator and the shift light both agree we are well over 8000. I was hoping the tach would validate those two so I could feel confident in making a gear change or to continue shifting it instead.
 
3,826
3,167
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
The MPH change from 8200 to 9000 is 11.4 mph, hitting 128.6 As short as those straights are, its not likely the speeds have increased that much.


Tire
25.6​
Rear Gear
4.10​
1st2nd3rd4th5th
T-56
2.66​
1.78​
1.30​
1.00​
0.80​
7900​
55.2​
82.4​
112.9​
146.7​
183.4​
8000​
55.9​
83.5​
114.3​
148.6​
185.8​
8100​
56.6​
84.5​
115.7​
150.5​
188.1​
8200​
57.3​
85.6​
117.2​
152.3​
190.4​
8300​
58.0​
86.6​
118.6​
154.2​
192.7​
8400​
58.7​
87.7​
120.0​
156.0​
195.0​
8500​
59.4​
88.7​
121.5​
157.9​
197.4​
8600​
60.1​
89.7​
122.9​
159.8​
199.7​
8700​
60.8​
90.8​
124.3​
161.6​
202.0​
8800​
61.5​
91.8​
125.7​
163.5​
204.3​
8900​
62.2​
92.9​
127.2​
165.3​
206.7​
9000​
62.9​
93.9​
128.6​
167.2​
209.0​
That makes sense, it’s probably the tach bouncing. That’s a relief. Thank you.
 
Last edited:
3,826
3,167
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
That tach needle is driving me crazy. You should email Autometer tech support with a link to the video. Maybe it's a bad unit.

It seems to "clean up" when you're full throttle, and be much worse when you lift. Crazy idea, but could you have tapped into an injector wire instead of a coil driver wire? Just thinking the bouncing could be due to injector duty cycle - it stops bouncing if the duty cycle gets over a certain percentage.
I don’t do any wiring so I have to imagine kevin knows the difference between a coil pack and an injector but we’ll certainly check that out. Goofy things sometimes happen.Thanks for the tip.
 
3,826
3,167
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
The MPH change from 8200 to 9000 is 11.4 mph, hitting 128.6 As short as those straights are, its not likely the speeds have increased that much.


Tire
25.6​
Rear Gear
4.10​
1st2nd3rd4th5th
T-56
2.66​
1.78​
1.30​
1.00​
0.80​
7900​
55.2​
82.4​
112.9​
146.7​
183.4​
8000​
55.9​
83.5​
114.3​
148.6​
185.8​
8100​
56.6​
84.5​
115.7​
150.5​
188.1​
8200​
57.3​
85.6​
117.2​
152.3​
190.4​
8300​
58.0​
86.6​
118.6​
154.2​
192.7​
8400​
58.7​
87.7​
120.0​
156.0​
195.0​
8500​
59.4​
88.7​
121.5​
157.9​
197.4​
8600​
60.1​
89.7​
122.9​
159.8​
199.7​
8700​
60.8​
90.8​
124.3​
161.6​
202.0​
8800​
61.5​
91.8​
125.7​
163.5​
204.3​
8900​
62.2​
92.9​
127.2​
165.3​
206.7​
9000​
62.9​
93.9​
128.6​
167.2​
209.0​
I’ll look at the dyno sheet but I’m pretty sure we are past the torque curve, and definitely past the hp peak. I’m really just concerned with that one short chute between 5&6 under the bridge. If I can get away with not shifting there I’d be happy and leave the rear end gear as is.
 
3,826
3,167
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
The MPH change from 8200 to 9000 is 11.4 mph, hitting 128.6 As short as those straights are, its not likely the speeds have increased that much.


Tire
25.6​
Rear Gear
4.10​
1st2nd3rd4th5th
T-56
2.66​
1.78​
1.30​
1.00​
0.80​
7900​
55.2​
82.4​
112.9​
146.7​
183.4​
8000​
55.9​
83.5​
114.3​
148.6​
185.8​
8100​
56.6​
84.5​
115.7​
150.5​
188.1​
8200​
57.3​
85.6​
117.2​
152.3​
190.4​
8300​
58.0​
86.6​
118.6​
154.2​
192.7​
8400​
58.7​
87.7​
120.0​
156.0​
195.0​
8500​
59.4​
88.7​
121.5​
157.9​
197.4​
8600​
60.1​
89.7​
122.9​
159.8​
199.7​
8700​
60.8​
90.8​
124.3​
161.6​
202.0​
8800​
61.5​
91.8​
125.7​
163.5​
204.3​
8900​
62.2​
92.9​
127.2​
165.3​
206.7​
9000​
62.9​
93.9​
128.6​
167.2​
209.0​
Yup, past everything.

CB441123-60E9-45F6-AA90-E8272078D1C6.jpeg
 
522
658
Exp. Type
Time Attack
Exp. Level
Under 3 Years
SoCal
As much credit as the Coyote gets for it’s high revs, I think the broad torque curve is really underrated. You could run that whole uphill section in 4th gear and be in the sweet spot of torque & HP. It won’t sound right to the ear, but I suspect you’ll gain MPH at the end of each straight. I’m running the same 4.10 gears, same trans, only with a bone stock gen 1 with 7,500 rev limiter. Earlier this year at Chuckwalla, I was struggling with the same thing at the tops of the straights. In the afternoon, I experimented with running the whole track in 4th gear with the exception of two slower speed corner complexes, where I geared down to 3rd. Heat of the day, and I dropped 3+ seconds off the morning runs. Again, my ear and brain were telling me the revs had to be faster, however the lap timer proved the torque band was faster by a lot. Anything past 8,000 is with diminishing returns and just not worth the added strain on the engine IMO.
 
3,826
3,167
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
As much credit as the Coyote gets for it’s high revs, I think the broad torque curve is really underrated. You could run that whole uphill section in 4th gear and be in the sweet spot of torque & HP. It won’t sound right to the ear, but I suspect you’ll gain MPH at the end of each straight. I’m running the same 4.10 gears, same trans, only with a bone stock gen 1 with 7,500 rev limiter. Earlier this year at Chuckwalla, I was struggling with the same thing at the tops of the straights. In the afternoon, I experimented with running the whole track in 4th gear with the exception of two slower speed corner complexes, where I geared down to 3rd. Heat of the day, and I dropped 3+ seconds off the morning runs. Again, my ear and brain were telling me the revs had to be faster, however the lap timer proved the torque band was faster by a lot. Anything past 8,000 is with diminishing returns and just not worth the added strain on the engine IMO.I started shifting up as I stated, don't know if its any faster, that will have to be looked into, my main concern is that the motor lives. It's just that one short chute as I said.....I don't care if its making less power, I don't want to shift up and then back down so quickly, it will only upset the car in a bad corner to do so. The Coyote motor is amazing and Shauns special "baby cams" and super tuning along with oil mods has everything to do with this ones success.

I started shifting up more in race 2, I don't know if its any faster, that will have to be looked into, my main concern is that the motor lives. It's just that one short chute as I said.....I don't care if its making less power, I don't want to shift up and then back down so quickly, it will only upset the car in a bad corner to do so. The Coyote motor is amazing and Shauns special "baby cams" and super tuning along with his oil mods etc. has everything to do with this particular ones success.
 

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