[Tigers] Stock Air Cleaner vs. Horsepower Dyno Results

[Rense, Mark (GE, Appl & Light)]

I promised a report on the restrictive effect of the stock air cleaner on
power on a recent engine build, just happened a little later than I hoped. I
had built a mild 331 stroker street engine out of a 289 5-bolt block, I wanted
a broad torque curve and a smooth running engine. If you are driving a Tiger
with a stock 260 or 289 you probably don't care much, but for us hot rodders
here is some data.

We had a thermocouple issue on the dyno, a bad Edelbrock carb out of the box
and time constraints that all conspired to delay the testing. Once on the dyno
the engine was broken in for 30 minutes, cooled, then run again for 30 minutes
to check for issues. All systems checked out, so we did the pulls.

The engine:
- SBF 289 5-bolt with Eagle 331 kit - 9.5:1 compression
- Edelbrock Performer RPM aluminum heads 2.01" intake
- CompCams XE262H Extreme Energy flat tappet hyd cam
- Edelbrock 289 Performer low rise intake
- Pertonix III distributor + coil
- Edelbrock 600 CFM carb #1406

We could not get the Edelbrock carb to jet correctly, dropping two sizes in
primary/secondary jets made the BSFC actually go up and exhaust temps go down.
I never got the engine to pull cleanly with this carb, even brought in a local
Carter carb expert and he was stumped. Repeated calls to Edelbrock eventually
resulted in a return authorization, but too late for our schedule. The engine
never made more than 315 HP and the lowest BSFC was .925.

A quick trip to Summit Racing netted a Holley 670 Street Avenger, it jetted
cleanly right out of the box. Both BSFC and exhaust temps in the ballpark, so
I leaned out the secondaries one step. Made several pulls with and without
stock air cleaner, the curves were very close below 4000 rpm so those numbers
were not included here.

With Tiger air cleaner + 1 1/2" K&N element:

Rpm      Torq      HP        BSFC
4000	379.5	289	0.444
4100	378	295.1	0.447
4200	376.4	301	0.45
4300	374.7	306.8	0.458
4400	373.8	313.2	0.467
4500	370.8	317.7	0.474
4600	367.8	322.1	0.479
4700	363.2	325	0.488
4800	357.2	326.5	0.495
4900	352.8	329.2	0.503
5000	349	332.3	0.501
5100	346.7	336.7	0.509
5200	344.8	341.4	0.507
5300	340.7	343.8	0.508
5400	335.1	344.5	0.508
5500	329.5	345.1	0.518
5600	321.3	342.6	0.528
5700	310.3	336.7	0.531
5800	301.4	322.8	0.535
5900	288.2	318.3	0.541
6000	269.3	307.7	0.553

With Moroso 4" round element air cleaner:
Rpm      Torq      HP        BSFC
4000	385.2	293.4	0.448
4100	383.6	299.5	0.441
4200	381.3	304.9	0.449
4300	378.2	309.6	0.46
4400	375.1	314.2	0.464
4500	373.7	320.2	0.47
4600	371.4	325.3	0.478
4700	368.4	329.7	0.485
4800	363.7	332.4	0.493
4900	361.1	336.9	0.499
5000	357.6	340.4	0.502
5100	355.4	345.1	0.503
5200	353.1	349.6	0.504
5300	350.6	353.8	0.507
5400	348.4	358.2	0.51
5500	341.6	357.7	0.515
5600	330.2    352.3	0.519
5700	324.9	352.6	0.521
5800	318.5	351.7	0.513
5900	311.9	350.4	0.509
6000	298.1	340.5	0.5

The stock air cleaner reduces the peak horsepower by 14 hp but more
importantly it lowers the power curve substantially, at 6000 rpm there is a 40
hp difference with and without the air cleaner. You can see the air cleaner
really start to restrict the flow at 5500, the BSFC starts to climb as the air
flow peaks. If you want more info email me off line.

 Bugz

-----Original Message-----
From: Rense, Mark
Sent: Thursday, July 05, 2012 10:23 AM
To: tigers at autox.team.net
Subject: Re: [Tigers] Air cleaner & horsepower

All,
I built a fairly mild 5-bolt 289 (Performer 1.90" heads, 500 cfm 4bbl, F4B,
CompCams XE262, Eagle rotating assembly, 9.5:1 compression, Pertonix in
dual-point, stock exhaust manifolds) for B382000991 about ten years ago and
when I ran the car on a chassis dyno I tried several air cleaner
combinations.
The best run was with a standard Edelbrock air cleaner with 4" element and the
car peaked at 273 HP at 6200 RPM. I put the stock Tiger air cleaner on with a
K&N 1 1/2" element. The flow was so restricted I had to open up the carb and
drop in a leaner set of secondary jets. The best we could get out of that
setup was 254 HP at 5800. So, the 20 HP loss is reality.

I just finished another 5-bolt 289 with a 332 kit and it is scheduled to go on
the dyno tomorrow for break-in and set-up. I plan to run a couple different
carb/air cleaner combinations, so I will include a stock Tiger air cleaner if
I have time. I have both 1 1/2" and 2" K&N elements.

Bugz