I was just checking out the specs of the mugen ecu, i have heard that it works really well with a stock motor (bolt on's). The vtec engagement is 4700rpm and the redline is 9100rpm.. Does anyone think that this is too early for vtec with a b18c5 with boltons? Im interested in hearing someone's experience with this ecu?
Thanks in advance.

 

i think for street driving, the lower vtec engagement might be a little too early. But the ECU isnt really meant for street driving. For road racing, i think the lower vtec engagement is ideal.

 

Having that approx. setting will help smooth out the spike (in the power curve) at factory vtec engagement point.

Will
-who wishes for a VAFC

 

I run 4400 all day long.....it drastically minimizes the aem spike from 4-5k. I watched the dyno runs at 5700, 4900, 4700, & 4400 & that's where I stayed.

With the mugen ecu I can't tell you how their fuel curve is set - so I would be careful if you aren't able to check it on the dyno before running vtec that low - wouldn't want you to lean out!

 

Anything less thatn 5,200 on stock cams is a bad idea. You lose midrange as the car tries to spool up the larger lobes from that low.

I did what you are supposed to, run the car with all VTEC (x-over at 3,000), ran the car with no VTEC (x-over at 7,000), and than you overlay the curves and see where the torque curve crosses. Where they cross is where you want to try and set the VTEC.

I tried 4,400, 5,200, and 5,600 (near stock) and played with the fuel settings of the first two. No matter how I tweaked it, I lost midrange (both versus the stock x-over ans the 5,200 x-over) with the lower x-over until around 5,300 or so. With a 5,300 x-over, it was a fairly smooth torque curve, and the transition was much better, and I gained midrange.

You shouldn't base your x-over on the AEM resonance effect ....... bad idea.

 

before you scream "bad idea", perhaps you should consider that different boltons may cause a different effect as to the egagement point and possible torque dips. For my R with the bolt-ons listed in my signature links, the 4400 point creates the best overal hp/tq curves. Since the original post only refers to "bolt-ons" without mentioning specific brands/combos, I didn't either.

Then again - they wanted opinions, I guess they got them!

 

someone hit andrew up about his mugen n1 ecu. he has a header, stock intake, and some kind of exhaust. he had some VERY good numbers.

 

From Pat's dyno run...
http://itr-nc.com/images/charlotte/patdyno.jpg

Sorry to steal your plot Pat.

Will
-who thinks lowering the point is a g00t thing.

[AEM at ~4200.... a smooth transition is nice]


[Modified by Willard, 9:41 AM 1/14/2002]

 

Depending on modifications, your VTEC point will differ from others.

4400 is not uncommon, especially on a motor with a 4-1 header and free-flowing exhaust. On my motor, the best point on the dyno was 4600. I find this kind of a pain in the *** for street driving because VTEC is always popping in.. so for the street I switch it to 5000rpm engagement and it's great.

 

Bleh.



j00 beat me to it. VTEC was lowered to 4700, I think. Notice smooth transition


[Modified by itr009, 9:45 AM 1/14/2002]

 

Does anyone know andrew's username? the bolt on's i have in mind are as follows.
comptech airbox, dc sports jdm 4-1, apexi n1 catback, mayb some cam gears....

 

https://honda-tech.com/zerouser?cmd=viewprofile&id=655

Those would seem to be appropriate bolt-ons, though you may also need an FPR (fuel pressure regulator) since it seems the Mugen computer likes about 60 psi of fuel pressure (vacuum off) using the stock USDM injectors.

 

The only plots I didn't get where the ones from my V-AFC addition ...... but it would show that for me, it was best at 5,300.

AEM cai, Comptech 4-2-1, Comptech catback, cam gears (+1,-4), timing at 17, underdrive pulleys, B&M f.p.r. (set at stock 52 psi off vacuum).

Every time I went lower, it would lose midrange.

:shrugs:

 

I fully expect for your mods & higher fp {I'm stock pressure} it was probably better....I saw different effects (noted by my +4intake, -1 exhaust cam gear settings). I do in fact get a drop after vtec engagement, but it doesn't drop below the BEST of any other combinations, so the drop is okay to me.

Thanks for listing your mods...that always helps in dicussions. Mine are listed in my sig link.

 

I have mine set at 3200rpms, I love it IM always in VTEC. I dont bog, just pure power all the way to the top


Mine is set at 5200rpms, even though on the dyno I wanted to do the VTEC overlay(1 at 3000, and 1 at 7000), but Mike k, bitched slaped me and said let the real tuner tell you what you need to do... he also kicked me in the nuts, I was very hurt, emotionaly

 

Hehehehehe.

It helped being the only one at the dyno when I did it that really knew about tuning VTEC cars .....

 

Huh, we had basically the same mods ....... just change the name of a few manufacturers (I didn't put plugs and wires down, because to me they aren't mods). I ran stock fuel pressure once I got the V-AFC (the stock off vacuum for me was 52 psi), and ran around 49 psi without it (to help lean it out a little). Interesting!

 

Yes, kicking you in the nuts was a real stress-reliever. Thanks for giving me the chance to do so, Mike.

Reason I didn't bother doing pulls @ 3000 and 7000 is because I know where a good point for VTEC is with your setup. And tell me, was I right?
Smack dab at 5200. Lowered it more, bogged. Raised it up, transition wasn't as smooth. You hear me talking, sucka!

Now bring me my game. I'll meet up w/ you tonight if you want.

 

Thanks for the feedback, so basically Mike K you think that 5200 is the idea vtec engagement point for a car with i/h/e, cam setting at (+1,-4) timing at 17.. ? With this setting is there a spike in the powerband?

 

You've got my settings there, and it made it a much smoother transition, with even pull.

Sounds like Mike K and his tuning of Vegata's car was very similar.

But with almost the same mods as me, Budman dropped it lower ........ with good results in his book. Just goes to show you, you need to get on a dyno and get it to suit your own car (like everyone always says when VTEC engagement and cam tuning come up).

 

4900 vs 5300 VTEC engagment
Lost a small amount of top end..but made the trsansition smoother and ganes some good midrange

 

I don't have online access to post my Dyno plot -- god damn photopoint.com! But I will post my mods.

Mugen N1 ECU
B&M FPR (set to 58psi)
drop-in K&N w/ stock airbox (minus resonator piping)
JDM Honda 4-1 header
Test pipe w/ resonator and exhaust dumping before the rear axle.
Timing set to 15 degrees (this is a road race car, so I need reliability over HP.)

188.x WHP
133.x TQ

We probably could have made it into the 190's with an advance in ignition timing as well as tuning the cam gears.

 

When I had the Mugen N1 ecu my car loved the 4600 x-over, power shot up when vtec hit on the dyno.

later
scott

 

Val, how in the hell does just changing the VTEC x-over effect the top end??? It should have absolutely ZERO effect on it. There's more to the plot than just changing the x-over.

 

I SWEAR that is all that was changed. I dont know why...but I was told before that when lowering the VTEC point..it will lose a slight bit of power in the top end.