Broken Spirit w/dyno results. Thoughts?
05-20-2019, 12:41 PM
#1
Broken Spirit w/dyno results. Thoughts? 
This last Saturday I had a change to dyno my project truck. It was a Mustang Dyno. We did three pulls total and the hightest number achieves was 308.5 hp WCF. This was a huge disappointment to say the least. I assumed that my build would AT LEAST do 350 if not closer to 400.
2000 RCSB Sierra
The engine is:
Gen III 6.0 LS bored .030 over (iron block)
Factory 243 heads milled .010 to achieve 10.9:1 Compression (No porting) w/springs and trunion upgrade
Custom Spec'd Cam by Pat G. and made by Texas Speed. (attached)
Electric Fan Conversion
Built 4l80E
Factory Intake
Factory 10 bolt w/cover upgrade and arp harware. 4.10 trutrac
Dyno operator spun the truck at 3500 to calibrate it. Final pull was to about 6800 RPM. Operator told me that the pulls needed to be in 3rd gear.
Was I wrong in thinking it would make more? Do the numbers sound right to you?
05-20-2019, 12:47 PM
#2
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Seems low. What's the dyno curve look like? Also, check your header primaries to make sure all 8 cylinders are burning.
05-20-2019, 07:40 PM
#5
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Headers?
I have a LQ9, 11:1 compression with 317 heads, stock intake with slightly smaller cam and I only made 290whp through a 4l60e. I do have stock exhaust manifolds though and I was pulling vacuum through the intake. I think the stock intake / TB was choking me pretty good and the exhaust.
I have a LQ9, 11:1 compression with 317 heads, stock intake with slightly smaller cam and I only made 290whp through a 4l60e. I do have stock exhaust manifolds though and I was pulling vacuum through the intake. I think the stock intake / TB was choking me pretty good and the exhaust.
05-20-2019, 08:23 PM
#7
4L80 trans sucks up a lot of HP
4.10 gears suck up a lot of HP
10.9:1 compression is low for that cam by about 1/2 point
Stock, milled 243 heads not optimal for HP
Dyno pulls should've been in 3rd (1:1) gear. If the pulls were done in 4th (overdrive) gear, that would most account for your low numbers.
KW
4.10 gears suck up a lot of HP
10.9:1 compression is low for that cam by about 1/2 point
Stock, milled 243 heads not optimal for HP
Dyno pulls should've been in 3rd (1:1) gear. If the pulls were done in 4th (overdrive) gear, that would most account for your low numbers.
KW
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05-20-2019, 08:34 PM
#8
I don’t like the cam. A cam like that is going to be a dog in a truck down low.
What kind of converter? Was it locked in 3rd? 4th?
Who tuned it? Total timing? AFR?
A lot missing from this.
What kind of converter? Was it locked in 3rd? 4th?
Who tuned it? Total timing? AFR?
A lot missing from this.
05-20-2019, 08:52 PM
#9
Long tubes. Dual 3" exhaust.
FTI 3200 Converter.
Local experienced and Reputable tuner.
Not sure on timing exactly. Will have to get back to you on that.
I was told it was locked in 3rd. My tuner was not present at the time. The was not a tuning session...just a dyno day.
FTI 3200 Converter.
Local experienced and Reputable tuner.
Not sure on timing exactly. Will have to get back to you on that.
I was told it was locked in 3rd. My tuner was not present at the time. The was not a tuning session...just a dyno day.
05-21-2019, 09:45 PM
#11
4L80 trans sucks up a lot of HP
4.10 gears suck up a lot of HP
10.9:1 compression is low for that cam by about 1/2 point
Stock, milled 243 heads not optimal for HP
Dyno pulls should've been in 3rd (1:1) gear. If the pulls were done in 4th (overdrive) gear, that would most account for your low numbers.
KW
4.10 gears suck up a lot of HP
10.9:1 compression is low for that cam by about 1/2 point
Stock, milled 243 heads not optimal for HP
Dyno pulls should've been in 3rd (1:1) gear. If the pulls were done in 4th (overdrive) gear, that would most account for your low numbers.
KW
05-24-2019, 03:17 AM
#18
4L80 trans sucks up a lot of HP
4.10 gears suck up a lot of HP
10.9:1 compression is low for that cam by about 1/2 point
Stock, milled 243 heads not optimal for HP
Dyno pulls should've been in 3rd (1:1) gear. If the pulls were done in 4th (overdrive) gear, that would most account for your low numbers.
KW
4.10 gears suck up a lot of HP
10.9:1 compression is low for that cam by about 1/2 point
Stock, milled 243 heads not optimal for HP
Dyno pulls should've been in 3rd (1:1) gear. If the pulls were done in 4th (overdrive) gear, that would most account for your low numbers.
KW
05-24-2019, 09:43 AM
#19
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05-24-2019, 12:48 PM
#20
I don't like the camshaft. It is way too intake biased.
You really need CNC ported heads for this camshaft and a higher flowing intake such as a fast. You also need more compression.
Seems to me that the converter is locked too.
A better specification would be a 226/236 113 LSA +3.
Less overlap so this means more low end torque and should pull better all over especially in such a heavy vehicle.
Plus this camshaft has the same IVC point with a slightly earlier EVO.
You really need CNC ported heads for this camshaft and a higher flowing intake such as a fast. You also need more compression.
Seems to me that the converter is locked too.
A better specification would be a 226/236 113 LSA +3.
Less overlap so this means more low end torque and should pull better all over especially in such a heavy vehicle.
Plus this camshaft has the same IVC point with a slightly earlier EVO.
