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Chasis Dyno Results 3.1 Stroker And Weber Dcoe 40


dawg7

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I am posting this information for reference only.  I already sold the Weber carbs with manifold and will be going either Z therapy SUs or Arizona Z 4 Barrel setup.  The reason for selling?  Just didn't have the skill or motivation to get educated on tuning the Webers.  Still up in the air on getting the Top end racing TWM throttle body system.   Kinda pricey at 3k minus the ECM.  Once I get one of those installed I will get back on the dyno. I think the carbs, canon manifold and the mild porting limited the HP.

Did a few chassis dyno runs last month and here is the best pull.   182HP and 189 TQ at max pull at 5800.  I also have an O2 wideband installed.  The AFR was 13.4 at an idle, 12.0 around 3500 and 11.1 at 5800.

The stroker engine is made up from this setup:

N42 block overbore 3mm
KA24E PISTONS ITM RY6660 CUT .5mm by machine shop
N42 head midly ported and polished; gasket matched
Cosmetic head gasket 1.2mm
Isky  L480 cam 480 lift 280 duration
71 240z connecting rods
MSA 6--1 header
2 ½ “ Magnaflow exhaust
Canon Intake
1979 280zx distributor  welded to 15 degree max advance(15 idle to 30 @ 3500 rpm).  Vacuum plugged.
MSD 6AL and MSD tach adapter
3 ohm Petronix flamethrower
Taylor 8mm spark plug wires

Weber DCOE 40-18 settings.

CHOKE                 34
AIR CORRECTION   180
MAIN JET             140
IDLE JET              50F9
EMULSION            F11
AUX VENT            4.5
PUMP JET            1.75
NEEDLE SEAT       1.75
INLET VALVE       .55

post-21697-0-04546600-1425937538_thumb.j

Edited by dawg7
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Nice numbers. I'm figuring the 42 head had no combustion work- reshaping.

afrs were kind of piggy at higher rpm. You might have lost some HP there.

I'm guessing timing was limited by knock?

Edited by madkaw
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Definitely the engine knocked at 32 degrees.  The idle was best at 17 degrees and only a mix of 100 octane and 93 (40/60 mix) would allow anything higher. The first weld ended up at 15 degrees and I stuck with that for the dyno run.   Might have put another weld on the dizzy and go with a 13 degree travel.  But I knew I was selling the Webers.  And the head was only gasket matched, nothing fancy. 

 

Snappy?  I sure enjoyed the torque but I thought the cam would go higher than 5800.

 

Reversed numbers?  The dyno shop put the lead on the coil as he couldn't get a reading from the plug wire.  Not sure if that affected the readings?

Edited by dawg7
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You posted 189 hp when the dyno sheet showed 189 torque(reversed).

I agree that the cam should have allowed good hp all the way to 6500rpm. You might have been drowning in fuel too.

Did you degree the cam?

All the reading I've done on these motors I would say the 42 head was your limiting factor. No quench head.

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Its water under the bridge so I did not want to bring up however since it has, it looks like the fuel level was too high and caused the mid band (cruise) and high RPM to be too rich. There is not much you can do to tune it out except lower fuel level or change emulsion tubes. I did the same thing at 25mm down. 27-29 looks like it should work better.

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