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Discussion Starter · #1 ·
Had my car at the dyno last night with the Turbo XS HPBC on it making just under 17 psi. Outside temp was about 85, inside the garage was about 90. I know the HP at 241 is OK, but I think its down because of the temp in the garage. More importantly how is my a/f ratio? Is ok, or do I need to back it down a bit?

 

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Hard to tell what line is what. Fuel looks happy though. its under 12 at the highest HP so thats good.

Thats if im reading the chart right. Cant tell what HP and tq is. No colors.

Did you hold 17psi up to red line? I think if you would have, you would have put down happier numbers
 

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bespoke said:
ExhaustDepot wrote:
Cant tell what HP and tq is. No colors.
Come on, how many engines make peak power at 3,000 rpm :?:
An SRT-4 that wont hold boost. The HP is the one that peaks first, note there is less peak HP than TQ, the second peak is taller.
 

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Look again. HP scale on left, TQ on right. TQ peaks first....by a long shot.

VV

el_jefe said:
bespoke said:
ExhaustDepot wrote:
Cant tell what HP and tq is. No colors.
Come on, how many engines make peak power at 3,000 rpm :?:
An SRT-4 that wont hold boost. The HP is the one that peaks first, note there is less peak HP than TQ, the second peak is taller.
 

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HP is a function of torque (ie torque*5252/RPM=HP), so because of this, it's obvious that whichever line is higher after 5252 RPM is the line representing HP, and whichever line is higher before 5252 RPM is torque.

*Since they use different scales for HP and torque here, they don't cross at 5252 RPM, but it still applies wherever they cross, so the higher one on the right side is HP, the higher one on the left is torque.
 

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Good explanation. Props.

VV

asherman said:
HP is a function of torque (ie torque*5252/RPM=HP), so because of this, it's obvious that whichever line is higher after 5252 RPM is the line representing HP, and whichever line is higher before 5252 RPM is torque.

*Since they use different scales for HP and torque here, they don't cross at 5252 RPM, but it still applies wherever they cross, so the higher one on the right side is HP, the higher one on the left is torque.
 

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Discussion Starter · #8 ·
Exhaust Depot said:
Hard to tell what line is what. Fuel looks happy though. its under 12 at the highest HP so thats good.

Thats if im reading the chart right. Cant tell what HP and tq is. No colors.

Did you hold 17psi up to red line? I think if you would have, you would have put down happier numbers
No, it dropped down to just under 14 psi at redline. I dragged my friends srt4 and pulled by a car right away, but only inched away after that. It doesnt make much of a difference when all your new power is low on the RPM range and you bang gears from redline. Both our cars at red line at 13.5 or so psi, so I lose any HP advantage I had. Hector, I need a pic on your wastegate extra spring you put on!! Also does it seem that 4500-5500 rpm's are rich enough?
 

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VetteVert said:
Look again. HP scale on left, TQ on right. TQ peaks first....by a long shot.

VV

el_jefe said:
bespoke said:
ExhaustDepot wrote:
Cant tell what HP and tq is. No colors.
Come on, how many engines make peak power at 3,000 rpm :?:
An SRT-4 that wont hold boost. The HP is the one that peaks first, note there is less peak HP than TQ, the second peak is taller.
oops. DainBramage. Yeah, I was looking at that half assed. My bad :oops:
 

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A/F

Ok, I have a stupid question.
How do they test A/F ratios with a wide band at the Dyno?
Do they have a way to tap into your cars system, or do you need to have a bung welded on to allow a sensor to be screwed in?
 

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Discussion Starter · #11 ·
Is it worth keeping the boost controller on if most of my gain is in RPM's that my car wont drop to when racing? Maybe I am not seeing this right, most likely I just dont know what I am talking about, but between 4400-5000rpm's the a/f dips below 10 on the chart, is this safe? And I am only gaining about 11hp between 4000-6000 rpm's. Like I said in another thread I dragged my buddies stock SRT 10-about 90 and pulled him by barely more than a car.
 

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Re: A/F

Pit Viper said:
Ok, I have a stupid question.
How do they test A/F ratios with a wide band at the Dyno?
Do they have a way to tap into your cars system, or do you need to have a bung welded on to allow a sensor to be screwed in?
they shove th esensor up your u know what, unles u have a bung hole somewhere right behind the car.


When the wb o2 is inserted in the tailpipe....and ure reading the chart....the results ar eofffset by about 500RPMS, due to the time it takes for the gases to reach the sensor.

Cali
 
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