I want to set up a hondata s300 systems with boost on my prelude. Hondata's site say's "Secondary intake runner operation will be lost if a P72 ECU is not used" What affect will I have if I used a p28 or should I just find a p72? Lets hear what you guys have to say...

 

First, you'll need to convert to OBDI to use Hondata.

Secondly, the P72 can control the IAB's (secondary intake runners). But a P28 will not, since Civic's never had the dual runner intake manifolds. Only the GSR and H23/H22's have IAB's.

If you're running an aftermarket intake manifold (like the Skunk 2 IM), you won't need the IAB function anymore. Otherwise, if you're running the stock intake manifold, you'll just lose the IAB function with a P28. As far as performance goes, most N/A guys reported losing some torque down low running w/o the IAB's. Upper rpms don't seem to be affected (it defaults to fully open). But since you'll be boosted, I don't think you'll experience losing any torque down low, if any at all. You can also remove the IAB plate altogether and maybe reduce turbulence without the butterfly assembly in the middle of the intake tract.

 

You really don't have to convert anything, just get an OBDII to OBDI adapter harness that plugs into the P72 or P28.

I use a P28 with NepTune RTP, and I still use my stock distributor, crank sensors, and injectors. My car is a 98 Prelude, BTW.

I run the butterflies open all the time, but my car seems to make very good torque. I'm happy to share my setup if anyone is interested. BTW, this graph was done in Excel using data exported through WinPEP. Tony Palo did the tuning on his dyno. The engine is 95% OEM parts.

 

Pirate gave us a direct IAB working/not working comparo on his special engine.

https://honda-tech.com/zerothre...14743

I have my own comparison, but it was on different days with different EMSes, at different levels of tune thus the differences in VEETAK. Those differences are not caused by IABs (in either case they're open past 4500 or so)

http://img262.imageshack.us/im...6.jpg

 

^ I would love to see your set up, I need more low end torque and would like to see if you switch anything over the an H23 part or something.

OP:

You running boost so honestly just get a P28 take out the butterflies completely if your boost they are just going to be a restriction.

I have a NA H22a4 running on Hondata S300 with a P28, I just disconnected my butterflies so they are open all the time, the low end torque was a tad bit of a probably so me below 2K but thats all changed since I got faster at shifting and my SMSP on

 

All the parts are H22. AEM CAI, SMSP header, fairly open exhaust with a Coast Fab muffler, Euro R crank pulley, Euro R TB. Port matched IM.

The engine was built to be a race engine, but everything was mostly kept within Honda's OEM specs. OEM parts are cams, pistons, rods, crank, IM, injectors, valves, etc. Head was milled to optimize squish, and a valve job was done on the head. ECU is a P28 with NepTune RTP.

 

Yeah after getting my SMSP on and street tuning it I'm sure I picked up low end torque all over the powerband.

getting on the dyno over at bisimoto on monday so I'll post up my results.

117 are you allowed aftermarket cams in your racing or no?

Right now my engine feels like it's dying for a cam, but it's a lot more fun around town not having to rev to 4K to get it moving anymore hehe