My F23A1 Dyno

[Chrisnick]

Prelude H23 eBay Intake tube
Blox aluminum velocity stack
AEM 6" dryflow filter
JVT "long tube" 4-2-1 header
2.25" test pipe+exhaust, 14" x 6" x 2.25" ID Magnaflow muffler
Timmytuning F23A1 chip/map/tune on a P28+ OBD2A to OBD1 jumper
62mm TB port-matched upper
Bisimoto intake manifold gasket
62mm H23A VTEC throttle body
thermal TB gasket
IAT sensor moved to intake piping

Car is crazy rich past 5K(AFR's in the 10's), and VTEC needs set at about 3200RPM. Lots of power left to be made by dialing stuff in. Going to add a ported/gutted F23 lower plenum/runners, chop up/ modify my H2B PLM 4-2-1 header, 3" exhaust, add the cam gear and retune. Total in mods+engine there's MAYBE $600 into this thing.

Two different B18C1 powered cars with bolt ons/tunes made 140-145whp/115-120whtq on the same dyno under similar conditions within the past week. My car door bangs with both of them.

[Chrisnick]

Bueller? Bueller? Bueller?

Anyone still wanna argue the F23A*/VTEC head sucks? So much power left in this without a cam it's silly. Unless you plan on porting an F22A head and adding a big cam, F23A* is probably the way to go.

[Rilas]

I've been very curious as to your results. Although I've just been busy and haven't had a chance to comment yet. This is very interesting.

I have an entire F23A1 disassembled on a bench, that I don't have a total plan for yet. I may have to look into porting and polishing the head and intake manifold.

Are you still looking at working on a camshaft with Gary for the F23A? If so I may look into that instead of his camshaft for the F22A.

[Chrisnick]

Not yet. We've briefly discussed it, but that's about as far as I've gotten. I think 180whp isn't out of the question with a stock cam on a well optimized setup. Porting the head isn't really necessary, I don't think, especially with a stock camshaft. Maybe some bowl work, gasket match/clean up the ports, and a good valve job would be about all I'd say it "needs" as they're already a pretty high flowing and high-velocity head. If anything, the biggest improvement will be chopping down the runners in the intake manifold's plenum and finding a length that works best. I'm going to gut mine completely and see where that lands power, and if it shifts it too high/loses too much torque, I'll chop up another one like how Gary does H23 manifolds. It's all a process. A good header design will go a LONG way, as well. Lots of things to play with. I'm willing to bet some $ that the reason why these engines stall out airflow wise at higher RPM is mainly from the intake runner length... I'll see what I can get out of this and keep it updated.

[Rilas]

How long are the intake runners on the F23A IM? It's been so long since I've even looked at that IM. Once I got it off the head it has laid on a shelf since.

[deevergote]

That's about 180hp to the crank, so assuming the thing was 100% healthy, that's only about 20 peak horsepower. I'd really be curious to see how much more you can make by properly tuning it! Still, 20chp/16whp isn't bad for basic bolt-on mods, and chances are the engine has lost some power with age, so the gains are likely a little higher than that.
With a proper tune and an upgraded camshaft, I bet you can hit H22A peak output pretty easily.

I'm only talking peak numbers, of course. I assume most of this has resulted in gains throughout the powerband.


Also, if you're interested in a camshaft, I believe Gude still makes them for the F23A.

[Rilas]

Web Cams makes one also but to the tune of $556 for a regrind. Here is the description. "Designed for hot street / drag racing. Requires Performance Valve Spring Kit." But for that kind of money it would just be worth looking into a hard weld cam. Here is a link to Webs' cam.

[lbus9168]

Thats quite a good HP/$ ratio. Great job man.

[Chrisnick]

I think the runners are about 14" long. I know I can get them down to about 7.5-8" long with gutting the intake. The torque is great, just from a driving back to back perspective, it feels WAY stronger than my friend's H22 Prelude up to about 6000rpm.

$556 could easily get me most everything else I need for a J swap haha. That's why I won't throw a cam in it.

[Rilas]

Yea $556 for a regrind is a little rediculous. I mean my Bisi Stage 2 Regrind was only like $330ish or something. I can't remember for the life of me right now.