I know i've read on here before that once you install any of the JDM style headers with a 2.5“ collector really prefer a lower VTEC engagement point. Does anyone have any ballpark figures for where it should be? I know the best way to find out is to dyno, but I don’t plan on dyno’ing until I get everything else done to the car first.

Any input would be greatly appreciated. Other than the VAFC, and Toda header the car is stock.

 

Go to a tuner and let them place it where the motor dictates.
Guessing could cause trouble.

 

i have an lsvtec, stock b16 head, ctr cams and itr intake manifold... with the today header, i brought my vtec x-over down to 4700 and it loved it. make sure to tune it up at the x-over though

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xjohnx &raquo;</TD></TR><TR><TD CLASS="quote">
Any input would be greatly appreciated. Other than the VAFC, and Toda header the car is stock.</TD></TR></TABLE>

With a stock exhaust (ie more back pressure) in order to get a smooth transition (most power) your vtec cross will be a little bit higher relative to a free-flowing exhaust. I would try 4800rpm to start - if the transtion is correct you won't feel any increase in torque/power when vtec engages - it will be seamless.

 

Yep, try 4800 as a start, but do it on a dyno so you have an idea of what happens when playing with the VAFC. I had my x-over @4400, with a Mugen intake and Hytech exhaust system and it could just as well have been set @4k, but that is a bit on the low side for daily driving as I would have been tipping into VTEC during cruising on the highway.

 

LOL -- john what are you doing with another ITR?

The last 2 R's that I had both had Toda headers, and per the dyno sessions I did they preferred 5200 x-over points.

That was with an AEM intake, and BCIII exhaust. Hit me up on AIM, I wanna hear about the new R.

 

On my Mugen ECU VTEC comes on at 4600 RPM.

 

Hey guys, do you have any dyno before and after the install of the toda header? In this way we can alsso se the gains in torque where vtec angages and deside about the apropriate vtec engagment point.

 

My tuner set my crossover at 4800.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by leader &raquo;</TD></TR><TR><TD CLASS="quote">Hey guys, do you have any dyno before and after the install of the toda header? In this way we can alsso se the gains in torque where vtec angages and deside about the apropriate vtec engagment point.</TD></TR></TABLE>

No but I do have a few good dyno plots that show VTEC points that are not in the correct spot, and also one comparison that shows the impact of changing from a race exhaust to street.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 Spec R &raquo;</TD></TR><TR><TD CLASS="quote">On my Mugen ECU VTEC comes on at 4600 RPM.</TD></TR></TABLE>

Incorrect - it's 4700 RPM. It's also irrelevant to the topic being discussed here, as Mugen ECU's are not programmed for TODA headers.

 

Seem like a good header like lower VTEC pt. My Hytech like VTEC at around 4600-4800RPM.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mugen Mike &raquo;</TD></TR><TR><TD CLASS="quote">Incorrect - it's 4700 RPM. It's also irrelevant to the topic being discussed here, as Mugen ECU's are not programmed for TODA headers.</TD></TR></TABLE>

Actually, the chip on my Mugen ECU says F/C 9000 and V/T 4600. I am not sure that I have a standard programmed Mugen ECU because of where I got it. Anyway, I am pretty sure that they would not write the wrong VTEC switchover on the chip. I am certain that it is a real Mugen ECU to.
Also, the post asked for a "ballpark figure" of where VTEC should be switched over at so I simply stated where mine switched over at. I do not see how that is off the topic of a ballpark figure. True, the Toda header is different however if you are going to get that specific, then the only true way to answer the original question would be to take it to the dyno and change the VTEC crossover points at various points lay the graphs over eachother to compare. Have a Nice Day!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 Spec R &raquo;</TD></TR><TR><TD CLASS="quote">

Actually, the chip on my Mugen ECU says F/C 9000 and V/T 4600. I am not sure that I have a standard programmed Mugen ECU because of where I got it. Anyway, I am pretty sure that they would not write the wrong VTEC switchover on the chip. I am certain that it is a real Mugen ECU to.</TD></TR></TABLE>

Where did you get it from? Do you have any pictures of the ECU casing and insides?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 Spec R &raquo;</TD></TR><TR><TD CLASS="quote">

Actually, the chip on my Mugen ECU says F/C 9000 and V/T 4600. I am not sure that I have a standard programmed Mugen ECU because of where I got it. Anyway, I am pretty sure that they would not write the wrong VTEC switchover on the chip. I am certain that it is a real Mugen ECU to.
</TD></TR></TABLE>

What are the case markings on the ECU? ....XH4-B2? B3, B4?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ausmith &raquo;</TD></TR><TR><TD CLASS="quote">What are the case markings on the ECU? ....XH4-B2? B3, B4?</TD></TR></TABLE>

37820-XH4-0000-B2

What is the difference between the B2, B3 & B4 ECU's

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mugen Mike &raquo;</TD></TR><TR><TD CLASS="quote">Where did you get it from? </TD></TR></TABLE>

I bought it from a guy who has one of your old 98 ITR World Challenge Cars. You probably know who I am talking about.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 Spec R &raquo;</TD></TR><TR><TD CLASS="quote">

I bought it from a guy who has one of your old 98 ITR World Challenge Cars. You probably know who I am talking about.</TD></TR></TABLE>

We didn't race a Type R in World Challenge, but we did race them in Grand Am Cup. Maybe you confused those two series or maybe another team like Realtime.

Realtime used the standard, off the shelf, 37820-XH4-0000-B2.

The specs on the B2 ECU for the DC2 Type R and SiR were 9,100 rev limit and 4,600rpm vtec cross.

To my knowledge the B2 version was the only one we ever imported to the US and that was also the last version made. There was a 37820-XH4-0000 (original configuration) and I'm not sure on the specs but I know we didn't sell any as there is no sales history in our database, actually that part number doesn't even exist in our data at all.

There was no B3, B4, or B-whatever for the DC2.

That's all I know on the subject

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ausmith &raquo;</TD></TR><TR><TD CLASS="quote">We didn't race a Type R in World Challenge, but we did race them in Grand Am Cup. </TD></TR></TABLE>

My bad, I got them mixed up it was a King Grand Am car.

Thanks for the information on the ECU's

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 Spec R &raquo;</TD></TR><TR><TD CLASS="quote">

My bad, I got them mixed up it was a King Grand Am car.

Thanks for the information on the ECU's
</TD></TR></TABLE>

No problem.

 

Why not just try some timed acceleration runs?

Here's Vtec at 3500 rpm with stock cams