vtakdis

thanks for the help, I actually picked up the 3" modded kamikaze header should be here Wednesday, gonna install it and have the exhaust shop mate it to the factory cat back for now, the e- cutout is probably the route I'm gonna end up going

xchipx

YEAH it is possible. I've seen it myself. Infact my bro is running 30psi in his tyres. 😂

Black R

^ IMO the stock catback (even itr) is a bottleneck.

That being said:

​​​​​​​APEXi Active Tail Silencer (ATS) for Honda Civic

looks interesting.

bigjon1378

iTrader: (2)

​​​​​​​it is a JDM ITR 4-1 I'd assume it's the best choice besides a Kamikaze, which I can not find. Also I am in Arizona, the exhaust is 2.25" no cat.

Black R

^ I figured as much.

I know my friends in Cali run a ported jdm 4-1 with the heat shield so they look carb compliant - you may have the same reason in AZ.

For boosted setups, I will always recommend 3" header back for power.

I know this isn't always practical due to noise / carb / emissions limitations...

Wasn't there a 3" big tube knockoff floating around eBay for a while?

I wouldn't mind testing one of those vs 3" kamikaze.

Anyway, a base map is just that - it should get you to be able to start the car and then you street tune a bit for partial throttle - preferably on the way to the dyno where you do your full throttle tuning.

Hopefully you have a wideband.

HeikDiesel

R, how's the car coming along?

Black R

I'm at a standstill.

I posted in this thread near the bottom:

https://honda-tech.com/forums/all-mo...tched-3047572/

​​​​​​​vtec-less and idk why...

vtakdis

that does look interesting! The header to stock exhaust is a temp thing, will add an exhaust in the future possibly but really want the car as quiet as possible even if it means loosing a few HP lol

CX-Adam

Take apart the rockers, vtec solenoid housing, and rocker rails and clean everything. You may have blockage or a leak between the cam caps and the rails preventing sufficient oil pressure from building up behind the pistons that lock the rocker arms together. Clean everything and replace the o-rings between the cam caps and the rails. I recently watch a video from nthefastlane that mentioned the o-rings as a common problem.

Black R

^ already did all of the above - no joke.

I spent all day Saturday going through every part of the head cleaning and looking for anything.

Disassembled all the rocker arms, cleaned inside them, lubed them, rocker shafts, basically everything in the head.

CX-Adam

Did you replace the o-ring?: VTEC NOT ENGAGING PROPERLY THIS COULD BE YOUR FIX - Nthefastlane

Clean the solenoid shafts?: MISTAKEN HEAD GASKET LEAK HONDA VTEC SOLENOID RESEAL - Nthefastlane

Seems like JRCivic may have already mentioned these things in the other thread but, just in case.

Black R

O-ring replaced, yup.

Cleaned solenoid and even tried another known good solenoid.

HeikDiesel

R,

Have you followed the FSM for vtec troubleshooting?

Black R

^ yessir.
I've gone through all tr troubleshooting procedures outlined in the Helms manual.

I posted mostly in that other thread.

It's not the solenoid.

It's possible that this head has an oil passage blocked bc it was used in an LSvtec build at one point - so I'm going to do the oil pressure test (bc it's failing the air pressure test), and also run an external LSvtec oil line to the passage on the intake side of the head at the oil port near the distributor.

2LEM1

iTrader: (1)

I was just reading through a bit of this for fun... why do you guys use a header with a 3" collector?

HeikDiesel

Why not? Forced induction application, I don't have any dyno proof but I would bet money that a 3" would gain power at all RPM vs a 2.5" or even a 2.36"

2LEM1

iTrader: (1)

I will take that bet.

You guys realize that 400whp N/A 2.4 liter K series are still running 2.5" collectors right?

You want velocity at the collector.

I'd be very curious to see any dynos at all of going from a 2.5" header to this Kamikaze header. I suspect power gains are doubtful.

In this multiple-hundred-page thread, is there a single dyno of anyone replacing a good header with the Kamikaze?

2LEM1

iTrader: (1)

2 minutes of research reveals that in 2017, you guys are still going off statements made by Larry Widmer in 2002... And also, Larry was using a Kamakazi header with a 2.5" collector, and the main reason he went with that header was the short primaries. However, large tube primaries would give you the same effect, and in 2017 I'm willing to bet there are better options that the Kamikaze header which was honestly a pile of **** 20 years ago.

But hey, I don't know **** about FI, so just ignore me.

JRCivic1

My HyTech header, custom built to my specifications based on a 300 wheel HP 1.9L high compression "B" series JRSC foundation, is a short primary, big tube, stepped 4-1 header with a 2.5" collector. I used this same header on my new Rotrex build and made 540 wheel HP. I am confident... and agree with 2LEM1... that a 3" collector on a "B" series JRSC engine will not perform any better than a properly sized 2.5" collector header.

Grifty

Has anyone run a D series JRSC on E85? If so what kind of power figures did you achieve?

Black R

NA and FI are pretty different imo.

I've seen no detriment from running 3" on boosted applications vs anything smaller.

Power just comes on earlier and gains are noticeable.

This reminds me of when people told me that open header NA would lose power and velocity bla bla bla back in 2000.

I did a back to back comparison on the dyno open header and got gains everywhere in the power band. Everywhere.

I'll post a dyno comparison if anyone wants to let me borrow a 2.5" kamikaze as mine is being modded with a 3" Vband collector.

That would be a very fair comparison because it's the same header.

2LEM1

iTrader: (1)

No argument here.

Butt dyno?

That's what I'm saying, has anyone over the last 15 years ever done a header test with a JRSC?

Yep. Anything PAST the collector is just a restriction. Backpressure is not anything you want, and bigger is always better when it comes to exhaust tubing.

It took Hondatech awhile to catch onto things, we didn't exactly have a ton of old hotrodders helping us or anything.

That would be awesome! I can't believe nobody has done that yet.

HeikDiesel

Guess I need to buy some 2.5 stuff and re-dyno

~sp33~

angryhillbilly

i went from jdm itr and 2.5 vibrant exhaust to Toda rep header with 3" thermal R&D exhaust. (both headers had 2.5" collectors) and i gained 12whp on the dyno (average of about 8whp across the whole rpm range). obviously this doesnt speak anything to the "collector size matters" but it does say, there is much more to it than that.