How much hp will the a4 header give?

[cb7sk8rdude]

If I replace my a1 header with an a4 header how much hp will I possibly gain. Or is there any gain in hp? The motor I have is f22a1.

[gvaldez92]

you will gain 5 hp. thats the only difference from the f22a1 and the f22a4. the header has tubular design for better flow.

[SuperTuner12010]

Not much, looking at 1-3. If so, I would go with an a6 cam, h23 intake manifold while your at it with a plenum spacer, add in a bisimoto intake manifold gasket. Healthy 13-14hp id imagine, and all pats can be found on ere for cheap...

[93Accordian]

I know a lot of people say that an aftermarket header won't gain you anymore than swapping the a4 manifold on, but has anyone ever dyno'd a car to show the official difference?

[gvaldez92]

F22AThis engine series was used in the Honda Accord and Honda Prelude S. Aside from differences in tuning, these engines are substantially similar.

Specifications

Bore × Stroke: 85.0 × 95.0 mm
Displacement: 2156 cc
Valve Configuration: SOHC, 16 valves, non-VTEC
Compression ratio: 8.8:1
Max power:
F22A1: 125 hp (93.21 4 kW) @ 5200 rpm. (Accord Dx,Lx) NOTE* The 1992-1996 Prelude S had a F22A1 but because of a different more aggressively tuned ECU (P12), the power output was 135 hp (100 kW).
F22A4: 130 hp (96.94 kW) @ 5200 rpm. (Accord Ex) The F22A4 is the same motor as the F22A1 but it has slightly more power due to a tubular designed header and slightly bigger exhaust piping.
F22A6: 140 hp (104.40 kW) @ 5600 rpm. The F22A6 is the same as the F22A1 except for a slightly more aggressive camshaft, a better flowing cast exhaust manifold, a different more aggressively tuned ECU (PT6), and a different intake manifold that utilizes IAB's and also has a bigger plenum. The F22A6 also has a windage tray in the oil pan, and stiffer valve springs to accommodate the more aggressive camshaft.
F22A7: 140 hp (104.40 kW) @ 6101 rpm
Max torque:
F22A1: 137 ft·lbf (186 N m) @ 4000 rpm
F22A4: 142 ft·lbf (193 N m) @ 4000 rpm
F22A6: 142 ft·lbf (193 N m) @ 4500 rpm
F22A7: 145 ft·lbf (198 N m) @ 5000 rpm

this is quoted from honda.

[Joey GT-R]

F22AThis engine series was used in the Honda Accord and Honda Prelude S. Aside from differences in tuning, these engines are substantially similar.

Specifications

Bore × Stroke: 85.0 × 95.0 mm
Displacement: 2156 cc
Valve Configuration: SOHC, 16 valves, non-VTEC
Compression ratio: 8.8:1
Max power:
F22A1: 125 hp (93.21 4 kW) @ 5200 rpm. (Accord Dx,Lx) NOTE* The 1992-1996 Prelude S had a F22A1 but because of a different more aggressively tuned ECU (P12), the power output was 135 hp (100 kW).
F22A4: 130 hp (96.94 kW) @ 5200 rpm. (Accord Ex) The F22A4 is the same motor as the F22A1 but it has slightly more power due to a tubular designed header and slightly bigger exhaust piping.
F22A6: 140 hp (104.40 kW) @ 5600 rpm. The F22A6 is the same as the F22A1 except for a slightly more aggressive camshaft, a better flowing cast exhaust manifold, a different more aggressively tuned ECU (PT6), and a different intake manifold that utilizes IAB's and also has a bigger plenum. The F22A6 also has a windage tray in the oil pan, and stiffer valve springs to accommodate the more aggressive camshaft.
F22A7: 140 hp (104.40 kW) @ 6101 rpm
Max torque:
F22A1: 137 ft·lbf (186 N m) @ 4000 rpm
F22A4: 142 ft·lbf (193 N m) @ 4000 rpm
F22A6: 142 ft·lbf (193 N m) @ 4500 rpm
F22A7: 145 ft·lbf (198 N m) @ 5000 rpm

this is quoted from honda.

This post did nothing to add to the discussion, other than restate what was already stated.

Anyways, why not just get an eBay or Megan header? For the price you'll pay in parts plus exhaust work, probably an extra $50 will garner more hp. I understand building on a budget, but when there are reputable options for cheap why not go for it? If you're working it may cost you waiting another 2 weeks for an extra paycheck......Just my thoughts.

[deevergote]

F22A1 and F22A4 are identical, other than the header and muffler. Everything else is the same, and the power difference is 5hp... so yes, about 5hp is what you can expect.

No, nobody has ever paid the money to do multiple dyno runs to determine which header gives more power. The aftermarket ones with larger runners probably DO give a bit more... but the difference is guaranteed to be so small (under 5hp) that it doesn't really justify the added expense... nor does it justify purchasing a part that will most likely fail sooner than a 20 year old stock piece would!

[gvaldez92]

only reason I posted that was cause he was saying 1-3hp from the a4 manifold, but its clearly 5hp just trying to give helpful truthful advice.

[deevergote]

5 is the difference from the original ratings, yes... but some of that MIGHT be due to the different muffler (possibly not a significant amount.) Also, with a 20 year old engine, the thing will be tired... so the gains will probably be less, simply because a tired engine (worn camshaft, worn valves/seats, worn internals, buildup on certain parts, aged and failing sensors...) won't respond as much as a fresh, new engine would. Brand new, stock for stock, there is a 5hp difference. Realistically, on our engines today, the difference is probably closer to 2-3.

[visualpoet]

Everyone forgets that the A4 had a slightly larger diameter exhaust as well, which added to that whopping 5 hp. Just changing from the A1 manifold to the A4 tubular manifold, nothing else, you MIGHT see 1 whp.

[SuperTuner12010]

As deeve and visualpoet said, a tired engine, and larger diamiter exhaust makes the differnece as well. Thus my reasoning for 1-3hp. The only way to make any real kind of power from a header is high quality, and the only true high quality production header that I am aware of for the f22 is bisimotos.

Havent had a cb in a while, dont rmember the differnece between the a6 and a4 manifolds? were they the same; I believe so. Either way the a4 header is an improvement, not much. But none the less an improvement, id reccomend using some seafoam as well to clean out the engine. Maybe help with some of the carbon build up as deeve was talking about.

[Tippey764]

As deeve and visualpoet said, a tired engine, and larger diamiter exhaust makes the differnece as well. Thus my reasoning for 1-3hp. The only way to make any real kind of power from a header is high quality, and the only true high quality production header that I am aware of for the f22 is bisimotos.

Havent had a cb in a while, dont rmember the differnece between the a6 and a4 manifolds? were they the same; I believe so. Either way the a4 header is an improvement, not much. But none the less an improvement, id reccomend using some seafoam as well to clean out the engine. Maybe help with some of the carbon build up as deeve was talking about.

the a4 manifold is made out of tubular steel where as the a6 manifold is made out of cast steel.

The a6 manifold is actually the same as the h23a1 exhaust manifold ( with pt6 stamps ). Im sure honda knows a bit more about header designs than us to have used that exhaust manifold on the better engines.


Also when you think about it the dx/lx exhaust has 1 tip. This tip is the same diameter as the ex with 2 tips. So essentially the EX has twice as big of an exhaust as an lx.

[Fleetw00d]

Also when you think about it the dx/lx exhaust has 1 tip. This tip is the same diameter as the ex with 2 tips. So essentially the EX has twice as big of an exhaust as an lx.

If you're talking about the muffler exit pipes, the EX pipes are each smaller than the LX pipe, although together they probably do provide more (but not 2X) the flow area. I had to enlarge the hole in an EX chrome tip for it to fit over my stock LX exit pipe.

[deevergote]

Is the exhaust piping diameter different between the cars with the F22A4 and the F22A1? I know the dual-tip muffler is different, but I thought the exhaust pipe diameter for all CB7s was 1.75".

[cb7sk8rdude]

Is the exhaust piping diameter different between the cars with the F22A4 and the F22A1? I know the dual-tip muffler is different, but I thought the exhaust pipe diameter for all CB7s was 1.75".

Mine is 1.75 and it is an lx f22a1.