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Discussion Starter · #1 · (Edited)
BORNGEARHEAD & I got some dyno time today at www.perfengine.com - good place for dyno tuning.

My NA car results are here. Turbo car in turbo section. BORNGEARHEAD will post his graphs in the VE section.

The dyno is a Dyno Dynamics.
They had a problem with the RPM signal, so it looks like peak RPM was 7000, but peak recall on the NisDataScan was like 7700 RPM.

87.1 deg F
29% humidity
1012 mb atmospheric pressure

NisDataScan info:
Stock DE MAF - peak 4.52 volts (@ 39 deg F I've seen 4.63 volts)
Stock DE injectors - peak 83.4% duty cycle (@ 39 deg F I've seen 86.8% @ 7612 RPM, 94.6% 7912 RPM)

***Edit: Video in gallery here (keywords JJP93SER_Gen6_S4_HP_TQ) :
http://www.sr20forum.com/gallery/showgallery.php?cat=547

HP vs TQ


HP vs AF
 

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Discussion Starter · #4 ·
Thanks!
The engine is the original US SR20DE & has 154,xxx miles on it.

Gen6 header w/ 3" collector, 3" magnaflow cat, 3" VRS cat-back w/resonator
JWT S4 cams
JWT ECU (pop program, not the S4 program)
UR 2 pc. pullies
Fidanza 8.x lb. flywheel
Nismo (Centerforce) clutch
AEM CAI
 

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Discussion Starter · #6 ·
STRATTON said:
great numbers, what was the timing at ?

stratton.
Thanks!

15 degrees

Thought about bumping it to 17 or 19, but remembered it's full of 87 octane 10% ethanol, and 87 deg F ambient, and wanted to spend more time on DJ's VE and my turbo car (bought 2 hours of dyno time, barely squeezed 3 cars in).
 

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Whaddya mean less than 120 ft-lbs?

Josh`s car moves. It is nothing like a near-stock SER. I`m surprised that the torque curve, although it was nice and flat, measured below 120 lb/ft sub 3500 rpm or so [I don`t have the graph in front of me at this point]. From just off idle it gets up and goes. No clutch slipping or mega rpm launches needed like some 4cyl sport compacts. Lessened vehicle weight (carbon fiber body parts - to chiseled out undercoat goo) plus light flywheel, crank pulley, ecu, and all that make the modest torque number less of a factor than many would think.

Good work Josh! Keep it slower than my shiny trailer queen, will ya?:eek2:
 

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Discussion Starter · #9 ·
Does anyone know how accurate the tailpipe sniffer widebands are, after a catalytic converter?
The A/F was about 13.4 from 6k or so and up, but doesn't the cat burn off some excess fuel before the sniffer would sense it - meaning it would actually be richer than what the graph says?

Also, it looks like the power flattens out and the torque drops off at 4800 RPM, where the A/F drops at the same point.
On DJ's VE, the torque started dropping about the same point, then at 5400 the big cam switches and it shoots up.
I sort of expected the power to ramp up, not drop off, with S4 cams?
I suppose I'd need cam gears to do any more tuning with this setup.
Thoughts?
 

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jp314 said:
Does anyone know how accurate the tailpipe sniffer widebands are, after a catalytic converter?
The A/F was about 13.4 from 6k or so and up, but doesn't the cat burn off some excess fuel before the sniffer would sense it - meaning it would actually be richer than what the graph says?

Also, it looks like the power flattens out and the torque drops off at 4800 RPM, where the A/F drops at the same point.
On DJ's VE, the torque started dropping about the same point, then at 5400 the big cam switches and it shoots up.
I sort of expected the power to ramp up, not drop off, with S4 cams?
I suppose I'd need cam gears to do any more tuning with this setup.
Thoughts?
They are horribly inaccurate! They are even worse on turbo cars. Don't even reference the #'s they gave you if that is how they sampled AF.
 

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Discussion Starter · #11 ·
wes said:
They are horribly inaccurate! They are even worse on turbo cars. Don't even reference the #'s they gave you if that is how they sampled AF.
My DE has a 3" cat, and I think DJ's VE has a 3" cat also - so I guess we can't trust the A/F charts then, except for the turbo which does not have a cat.

They said their tailpipe wideband is better than my AEM UEGO (in the turbo car, mounted about 24"-30" from exhaust port) since their's is high speed or high resolution but the AEM isn't.
Guess I'll have to hook up a laptop to the AEM datalog port to see what kind of graph I get with that.
 

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jp314 said:
My DE has a 3" cat, and I think DJ's VE has a 3" cat also - so I guess we can't trust the A/F charts then, except for the turbo which does not have a cat.

They said their tailpipe wideband is better than my AEM UEGO (in the turbo car, mounted about 24"-30" from exhaust port) since their's is high speed or high resolution but the AEM isn't.
Guess I'll have to hook up a laptop to the AEM datalog port to see what kind of graph I get with that.
Well here's the deal, ANY exhaust leak on the turbo car will throw off the AF. Also readings are ONLY as good as the sensor. Do they ever dyno race cars on leaded gas with the same sensor? See where I am going with this? MOST places suck when it comes to readings and sensor's. Any place that has a Horiba or has multiple sensors based on car and fuel type is probably doing things right. Otherwise I would be suspect.

I bet the AEM is more accurate if it is closer to the turbo.
 

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Discussion Starter · #14 ·
se-r pastor said:
I'll bet there are NO leaks on the turbo car. Silly monkey that put that together.
Turbo car:
I'm pretty sure there are no leaks before the wideband.
I just had it apart to install the wideband, and put it back together.
It looked pretty tight.
I know there some leaks a foot or more downstream of the wideband, but that shouldn't matter.

The AEM was showing 10-11 WOT low to mid RPM, 12-13 WOT high RPM, IIRC.
Would get better numbers from the datalog port than from quick glances while driving though. :)

NA car:
There shouldn't be any leaks - all new exhaust, header back.
 

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jp314 said:
My DE has a 3" cat, and I think DJ's VE has a 3" cat also - so I guess we can't trust the A/F charts then, except for the turbo which does not have a cat.

They said their tailpipe wideband is better than my AEM UEGO (in the turbo car, mounted about 24"-30" from exhaust port) since their's is high speed or high resolution but the AEM isn't.
Guess I'll have to hook up a laptop to the AEM datalog port to see what kind of graph I get with that.
i have an AEM with wideband on my car and when we tune it on the dyno... the AFR's are about 0.2 to 0.1 off. That's not a significant change to alter anything. Turbo cars or not... the wideband on the DD machines are pretty rock solid. We even had an innovative WB readers with different cars and they were 0.2 off from the dyno. Again, not a significant change to make any substantial amount of change on your performance.

You'll be quite amazed how well the WB readers on the DD machines are.
 

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panapower said:
i have an AEM with wideband on my car and when we tune it on the dyno... the AFR's are about 0.2 to 0.1 off. That's not a significant change to alter anything. Turbo cars or not... the wideband on the DD machines are pretty rock solid. We even had an innovative WB readers with different cars and they were 0.2 off from the dyno. Again, not a significant change to make any substantial amount of change on your performance.

You'll be quite amazed how well the WB readers on the DD machines are.
Yes I am serious.

This is a blanket statement that is ONLY relative to the quality of the car build (exhaust leaks etc..) and the people that maintain the sensors. While they are somewhat resiliant, they are not bullett proof, and when trying to sample AF ratio to adjust tune I don't trust anyone that doesn't maintain and or calibrate their setups regularly. And that is 90% of the people that own dyno's that have wideband sensors.
 

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Corr Performance Tuning
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wes said:
Yes I am serious.

This is a blanket statement that is ONLY relative to the quality of the car build (exhaust leaks etc..) and the people that maintain the sensors. While they are somewhat resiliant, they are not bullett proof, and when trying to sample AF ratio to adjust tune I don't trust anyone that doesn't maintain and or calibrate their setups regularly. And that is 90% of the people that own dyno's that have wideband sensors.
if he has an exhaust leak then the wideband will read just what it gets... with or without the exhaust leak. These sensors are exceptionally strong considering the enviroment that they are in. Yes they get damaged quicker with race gas. Yes they get damaged with condenstaion. Most of the shops that we know take care of their widebands... why? cause they are NOT cheap. The only way to find out if the wideband is off is to take it to get the car sniffed, use another wideband at wot or use a WB reader to log the results. If they results are less than .4 off.... then he's fine. If they are more than that then there is speculation that their wideband might be off. If there is nothing to compare to the reading that the machine gave... how is one ever to compare?
 

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jp314 said:
Turbo car:
I'm pretty sure there are no leaks before the wideband.
I just had it apart to install the wideband, and put it back together.
It looked pretty tight.
I know there some leaks a foot or more downstream of the wideband, but that shouldn't matter.

The AEM was showing 10-11 WOT low to mid RPM, 12-13 WOT high RPM, IIRC.
Would get better numbers from the datalog port than from quick glances while driving though. :)

NA car:
There shouldn't be any leaks - all new exhaust, header back.
Forgot you had the AEM, definately would be bad to use the tailpipe sniffer on the turbo car
 
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