Playing around with the ignition timing will allow you to tune for torque though once proper A/F has been set. So that is where you will be able to pull the additional gains in hp.

 

[QUOTE=gernby,Oct 31 2004, 07:29 AM]
Ignition timing is NOT where all the power is.

 

I don't know what the intent of posting the innovatemotorsports link was, since it seems to deny your claim as much as it supports it. Almost the entire article is dedicated to air / fuel, with only a single sentence (that I saw) that mentioned ignition timing.

The P1auto dyno plot is puzzling to me. I went to P1auto's web site, and it doesn't show this plot. However, it does show dyno plots from their S2000 project car. The puzzling thing about this is that their project S2000 started off with more power than the one you showed (base line), then only benefitted 17.9 hp with the addition of AEM CAI, Mugen cat-back, Mugen thermostat/fan switch, Toda Racing Header, and AEM EMS. That really doesn't show much support for your beloved EMS. I picked up 13 hp with fewer bolt-ons that were tuned only for AFRs.

 

like I said, do your own research and I'm not trying to argue with you about where you will find power.

It's a good article, if you have never read it before.

by running rich you are effectively retarding the ignition timing... while wasting fuel.


instead you could just retard the ignition timing with a form of timing control and maintain a much more efficient burn and not blow the gas mileage or leave nice black soot on the bumper.

 

Is this with other bolt on mods too or just bone stock s2k?

If it's the later case I find that very hard to believe too. You will gain some power after vtec but not very much b4 vtec at all. I would think it's a lot more to do with dynovariation and who turn what knobs.

Sure, you can gain some more power with the stock f20c with correct intake and exhaust mods. However there are little difference in gain between a vafc and aem ems for such application. The only real extra benefit of the aem ems is that you can readjust the knock sensor where as the piggyback + stock ecu combo is fixed. I believe this is partly why the s2k loses power when you lower the vtec engagement point due to knock control. This is only my theory and has not been tested yet. What do you guys think of this theory ? Has anyone successfully changed vtec engagement point with the aem ems and stock/near stock motor without losing power.


BTW the aem ems dyno gain on the aem forum was with a V2 aem intake.


Nice result whites2000@16. Thanks for sharing

 

The actual numbers of a dyno can be manipulated by correction factors or gear calculations, but the shape of the graph will be the same.

when you look at dyno graph the horsepower plot will show you the VE of that engine. you can see in some how power will start to fall off up top, the engine is probably choking... or not getting enough air. there are a few trick ways to tell if the cams, TB, Exhaust may be the limiting factor or bottleneck.



Changing the VTEC crossover within a few hundred rpm up or down will only smooth the transistion, on a stock cam/intake/exhaust engine. The way to tune for the best power out of a vtec engine is to tune with it off up past your estimated vtec crossover; and then tune with the crossover set well below your estimate. the point where the two plots cross is where I would set the crossover to start tuning...

This works for FI and n/a.. you will probably find a much lower crossover can be used with FI.

 

That doesn't work as well as it sounds. Setting VTEC lower than optimum will cause a dip in power that extends beyond the optimum point. You also have to carefully tune the air / fuel ratios before and after the VTEC engagement to give a "best case" VTEC transition. What worked best for me was to set my VTEC engagement point at 5400 RPMs, clear the fuel controller, fully tune with the WBO2, look at the resulting curve, then raise the engagement point to 5500 RPMs, clear the fuel controller .... on and on. This wasn't easy, but the results were much better than when I used the "intersection" method.

 

I only said it was a starting point. If the engine is not heavily modified, the stock crossover is a good starting point.

 

What worked best for me was to set my VTEC engagement point at 5400 RPMs, clear the fuel controller, fully tune with the WBO2, look at the resulting curve, then raise the engagement point to 5500 RPMs, clear the fuel controller .... on and on.

We know that vtec is noisy and if you drop VTEC engagement point too low the oem ecu might think that it's knock rather than normal vtec noise. I had the same experience when I had the VAFC and AEM intake.
Do you think that the power loss is due to the inbuilt knock control on the OEM ecu?

 

Possibly, most of my experience is with stand alone (aem) and not piggybacks. With a standalone you will be able to see what the knock sensor is doing, and by what the power is doing you will be able to tell if it's knock or noise.