B20 Dyno

Dyno Session #2  Dyno Session #3

  Dyno Session #1

Final curve from the dyno session. No ign, fuel or cam timing tuning was done.

98 B20B stock head and block, 94 P75/LS ecu
Intake: GSR stock cone filter and tube (no airbox), LS intake manifold, 64mm TB
Ex: GSR exhaust manifold, test pipe, Greddy BL exhaust
Comments: 128hp to the wheels is rougly 150hp to the flywheel. Interesting since the engine is rated only 126 hp flywheel. The increase in power can probably be accounted to the GSR exhaust manifold, free flow exhaust and the LS intake manifold. The stock cast GSR exhaust manifold that was used looks like a better piece than the stock stamped and welded CRV part. We did not have a matching down pipe for the CRV ex manifold, so we could not try it to be sure. The intermittent glitch at ~6200 was later discovered to be a loose crimp connector on the ignitor. Since it was occuring after power peak, it really doesn't hurt the results. The 64mm TB probably is not needed at this power level. Not yet ;)

Replace old cat with 2.25" test pipe.

The -5 hp stock cat mod. Remember kids, the stock Civic cat is not a high flow design after many years of use and abuse. Brand new Honda cats work good. But over time they start to hurt the flow. Dyno proof right here. We did a couple runs to make sure the car was back up at operating temp to improve the accuracy of the comparison. A new cat is on order.

Look at the torque. Torque you can feel. The lag in the power band from 3.5k- 4.5k will be the target of a future dyno session. You can feel the engine labor through it a bit. But when it reaches 4.2K, hold on, because it ramps up in a hurry.


B20B P75/LS ecu vs P06/DX ecu vs B18C1/GSR ecu.

Hrmmm, the DX actually makes more peak power and more power past 5700! The stock cams want a leaner mixture on top than the LS ecu is delivering: leaner is meaner. The LS ecu is the obvious choice for plug-n-play. However the DX shows that there is more power potential on top with fuel and timing tuning. You'll notice that these runs where done with the -5 hp cat in place.

The GSR ecu is a bad choice. Check Engine light was on, throwing VTEC oil pressure codes so the ecu was not using the VTEC fuel maps.

A 92 LS ecu was tested and was exactly the same as the 94 LS ecu.


B20B vs my old and getting tired B18C1.

The B18C1 was dyno'd 6 months ago at another facility, using the -5 hp cat we discovered above. However, look at the torque curves. The B20B feels stronger than the B18C1, and does not have to be rev'ed as high to get to the power. It's beating the B18C1 by ~ 15 ft-lbs at 4500 rpm. Can you say "roll-on passing power?!!!"

Also, the B18C1 shows the AEM CAI bump at 3700 rpm. The B20 might want a bump centered at about 4-4.2k rpms.

  Dyno Session #2


What's new:
4-1 header, insulated with Thermotech wrap 2.25" Carsound cat Magnaflow Street cat back exhaust Shogun Fuel Tuner


I had to switch dynos, because the guys at the other dyno were kinda jerks. The new place is DynoSpot Racing. I paid regular price, so no hook-ups here. They treated me fair and I will be back.

Red curve is from the new dyno session, the blue curve from the old session.

Not quite the gains I expected to see. I changed the complete exhaust, and am not 100% sure I changed it for the better. Next time I will probably switch out the exhaust and cat to get a better picture. Also, the B20B cams are obviously not high rpm cams, so adding the header at this stage is premature. The header won't shine until I add the Crower cams, and raise the power peak rpms.


Tuning the Fuel and Timing with the Shogun

Played with the Shogun for quite awhile, adding and subtracting fuel until the power went down. Leaning out the top end made a very small gain, but is probably not worth the risk of running too lean. However, the gains on the bottom end were impressive. Retarding or advancing the timing on the top end did nothing to the power curve, but advancing it on the bottom made a big dyno difference and a BIG street difference. On the street the increase pull was felt from 1500 rpm. Very interesting. And satisfying. The Shogun also makes it easy to raise the fuelcut, in 100rpm increments. I set it to 7000, though as you can see from the dyno curve, there is little reason to go that high right now.

I have begun to call the region between 3.5K and 4.5K "No Man's Land" because I can't make any more power there. With the Shogun we could only hurt power in that region. Look at this graph of a LS motor with Crower 62403 cams from Crower's web site and you can see that even with cams and cam gears, that area stays untouchable.

My hunch, and from asking others, this might be an intake manifold phenomenon. Shawn's ITR manifold on a stock LS shows that changing the manifold certainly affects the shape of the curve more than changing cams.


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