If you read your plugs at WOT, you will often notice that there's always one or two cylinders who are "off song" from the others. I guess with a single plenum manifold there's a lot of cross talk between cylinders and how one cylinder is filled affects the way it's neighbouring cylinder breathes. The poor sap is usually cylinder 3 which runsthe hottest because it has to share it's walls with 2 rather than 1 cylinder.

Anyway, since we really don't have the luxury of changing the firing order to 1-2-4-3 from 1-3-4-2 or running custom grind cams for an oddd ball firing order, I was reading that many advanced racers use rocker arm ratio adjustment to get the one cylinder that is lagging behind from the others back up to speed. You stay within factory or cam manufacturer rocker arm ratio limits but adjust them so the 1 cylinder breathes a little more than the others. Bringing all cylinders up to the same level should make the engine spit out a little more punch....I'm sure the header builders can comment on tuned lengths/diameters for individual cylinder breathing...

Has anyone played around with this notion or is this a little dicey and better left alone?

cheers
Tuan

PS I've noticed that someone put up all the cam specs for the Bseries. Good job but not to be a spoil sport, I've had those up for years at SHO and now at team-integra.net and allmotorhonda.com has also had them up for awhile....don't laugh but I think the intriguing cams that no-one has tested are the Zex 57300 cam with 13.2 mm lift & 260 duration @1mm on the intake side...It would be nice to get the new Crower race cams 63411-413 duration @1mm and HyTech's roller cam specs. What would also be new to bring to the table are ramp/flank angles and lobe separation angles....are you listening Frank (Frank Lin was compiling a list of B series cam specs for the Powered by Honda section of G-speed.com the last I heard....)?


[Modified by Michael Delaney, 7:13 AM 4/8/2002]

 

Good idea. Wonder how effective it is.

Rollers = kick ***.

 

what we normally do it to make a very highly tuned car is to put 4 O2 sensor on when we are tuning it to get perfect reading of AF by drilling 4 holes on the 4 primaries on the header and put small Autronic O2 sensor there. By doing that, you can tuned every cylinder perfect, no cylinder richer than others. MOTEC or Autronic or FC Pro needed as you have to tune each individual cylinder and of course direct ignition is needed too, so you are working on each cylinder instead of working on whole engine intake and exhaust.

Thats how we build our track car anyway, not sure of how ppl tuned their car perfectly for their drag setup, I guess for drag, the bigger the turbo is the better

 

one header for tuning and one for racing?

Will

 

So you need a standalone computer , direct ignition, and 4 autronic sensors near the flange of the primaries....hmmm...I think that's a little out of most of our league pricewise here.

Is there a simpler, less costly approach for us plebs to bring the cylinders up to equal volumetric efficiency?

does the hondata do this sort of thing?

the Midget and Sprint racers use the rocker arm ratio trick...this is where I picked up the idea...anyone?

 

 

not worth the effort IMO.... think about it this way, bowtie and blue oval have had many aftermarket companies around for a long time, different rocker ratios are readily available, and inexpensive. agree?

 

For most purposes I think you are splitting hairs with this notion. Wouldn't you be better off tuning the individual injectors?

 

What exactly do you mean by "rocker arm ratio adjustment"? (pardon my ignorance on this subject)

 

Couldn't you achieve similar results with egt sensors in each primary? It would be a little cheaper I think(but not as acurate ).

 

I guess any AF meter will do, at least it will be better than 1.

 

any sequential e/m can do it once it reads the "reset" trigger it knows which cylinder its firing so you have ability to run leaner/richer and less timing. I use the Speedpro and I control it that way. John also catered for #3 running different when he made my header.
I always go looser lash on #3 too.

also a secret ... if you analyze any Toda camshaft you'll see what Toda did to the #3 lobes ... All the copycats out there never thought of that when they were copying either LOL.

Greg

 

if you ever measure wear on the cylinders, cylinder #2 is usually similar to #3 in that they both have higher wear rates than #1 & #4 , generally speaking. So I would think cylinder #2 would need special attention as well.