I just put on my 4-1 1 piece header on my d15/d16 motor, and now it seems A LOT slower than what it was. Ican think of several different things it could be. 1- Not any back pressure at all, no cat. 2 - i was taking out the o2 sensor and the damn wire came out so i tried to solder it what i could. 3- i still have the stock d15b2 intake mani on, with short ram air intake.

I had to cut the crossmember to make it fit but it is still sitting on the crossmember some, and because of this the car shakes pretty bad now. I cut just the lip off of the crossmember and i figured that would be enough. Does anyone know if i should cut more or would that sacrifice a lot of my handling? Rather annoying to finally get this thing on and it makes my car louder, shakes, and slower.

Any help would be awesome,
Thanks,
Matt

 

MPFI swap is all i can say

 

your problem is simple, the 4-1-1 has **** for low and bottom end power, its all about the high upper end. 4-2-1 is superior for the street because it makes superiour low and mid range torque, with only a little less high end than the 4-1-1, that is only good if you live in the upper Rpm range, and on the street that NEVER happens.

 

Well i did not lose, just a little power it was A LOT, i have my typical test run i always have, with my new motor, i would always hit 65 without a problem, but just when i put the header on, i got like 60mph which is awful, and even in the powerband and upper ranges, the climb to 6500 is awful. Not even close to what it was. If the 4-1 design is really that awful let me know, i did not realize it was this bad.

Thanks,
Matt

 

I am newbie, first post. Converted from Corolla GTS to CRX.
We have two second gen CRX si road race cars. Mine has the 4-2-1 manifold and it is very torquy. The other new car has 4-1-1 and both drivers , who have raced my car for a season, say mine is better. Their car is too peaky and all the power is at the top end. They both say now they have to keep up the revs more to make power. In fact they are looking for another manifold like I have. Apparently off of an Integra? I am not sure. Our production based race class does not allow the use of a header. 4-2-1 definitley the way to go.
I would also say any cutting of the crossmember is a no no.

 

SAME exact thing is happening to me, my 4-1 headers are bogging like a bitch on take off.

 

there will be a big difference , a search before you spent the money would have been time well invested. Plenty of threads have discussed this before. Only place 4-1-1 has any edge at all and its a small one it HIGH RPM, it losses everywhere else. And a D series engine tends to run out of steam before it can really use the range it does work in.

My advice, sell it to some riceboy and buy yourself a 4-2-1 and enjoy what it has to offer.

 

OK the 4-1 will make more torque than a 4-2-1 due to the longer runners. It's a fact. Upgradding to a header isn't necessary unless you have head work or cams. Headers will help remove exhaust from the head. You will get more power but not much since you aren't forcing any more air into the engine. Exhaust systems need back pressure to work efficently. What size diameter exhaust pipe is on the car? To get good results (torque) at lower RPM you need a scavenging effect from the exhaust. This happens well at higher RPM, but at lower RPM the voulme of exhaust is lower reducing the scavenging efect. Some how back pressure aids in this scavenging effect, I don't know how. I guess it slows the exhaust gas speed down at a slow enough pace to get that suction efect on the closing exhauust valves. Anyways a race car will have a muffler that you can see through or none at all, but they don't put around at speeds under 4K or 5K RPM. So with this high volume of flow thew scavenging effect is already there at those engine speeds. Yes you might loosed some HP on the top end 4-8K RPM, but it will be minimal unless you have tun ed the engine to stay in that range. For the stop and go driver you need more torque because that is what you feel (not the HP), that is where you will benifit greatly from a baffeled muffler or some back pressure. ANyone confused YET?

OH yah, the O2 sensor doesn't work under full throttlr. THe ECU stops using it for input since it is an emissions device, and uses a preprogrammed map for full throttle or WOT.

 

Sorry to disagree with you, a 4-2-1 DOES make more mid and low end torque than a 4-1-1, dyno test prove it. the 4-1-1 makes more HP over 6,000 prm thats a fact, do a search, there will be more threads confirming what I just said than you can read over the weekend.

 

I'm taking a stand and calling bullshit on every single large exhaust myth I see. Someone post a before and after dyno that proves that a 4-1 header produces less low-end torque than a 4-2-1 (or stock) and I'll eat my hat. There are no physics to explain how back-pressure helps in any way. I've seen a lot of before and after dynos, and every single one proves that bigger is ALWAYS better when it comes to exhausts (including headers).

As for this guy, I'd guess it has something to do with the O2 sensor you say you butchered.

 

no backpressure does not hurt performance in any dramatic way, especially if you felt A LOT of performance loss. the stock manifold on the dual point motors SUCKS, believe me. i've done quite a bit of research into exhaust theory/design, and have created many many exhaust systems.....and a few headers also, and bigger is pretty much always better....if you want to get specific, you can get into the theory of anti-reversion chambers, etc, but that header is NOT what hurt your performance, something else is wrong.. get a tune up and a new O2 sensor, and i bet things will happen. sorry if i seem cranky, i'm not, i just want to re-enforce that no backpressure does not hurt performance, especially where honda's live, which is HIGH HIGH HIGH rpms......seriously. good luck, hope you figure this one out...what kinda header is it?

 

He is probably hurting the performance of his engine b/c he has a D series motor and the 4 to 1 header is made for high RPM use. His engine is simply not pushing enough air out of the engine for the header to make a difference.

I don't know the specifics of his setup so I can't tell exactly what the problem is. Does he have a 2.5 inch collector? What size exhaust pipes does he have?


When I put my JDM 4 to 1 header on it made a BIG difference, but my motor isn't a D series motor.


EDIT: 4 to 1 header hurt my low end a little but only under 3K RPM, which doesn't matter with the gears I have.


Modified by hybrid honda at 12:14 PM 11/21/2003

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote"> that is only good if you live in the upper Rpm range, and on the street that NEVER happens</TD></TR></TABLE>

I dont know how you drive, granny, but if i race (or even just drive around for that matter), i pick a gear and pay the redline a visit.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by steronz &raquo;</TD></TR><TR><TD CLASS="quote">There are no physics to explain how back-pressure helps in any way. I've seen a lot of before and after dynos, and every single one proves that bigger is ALWAYS better when it comes to exhausts (including headers).
</TD></TR></TABLE>

We all know that backpressure isn't what creates maximum power, it's flow velocity right?

If you go way too big in piping diameter, you'll sacrifice flow velocity for flow potential (which is not necessary without big cam/headwork/forced induction/nitrous etc.) and THAT'S what kills power/torque.

 

Believe me I do not drive like a granny, but I guarantee you you do not live at 6,000 rpm and up for very long, I guarantee you spend MOST of yout time below 5,000 rpm, thats exactly why a 4-2-1 is superior on the street. And on a D series engine that very small advantage is even narrower because they typicly don't rev to 9,000 rpm. SO before you talk I recomend you checking your facts. with the engine he is running I guarantee you it is not a track only car. AND if you do manage to run around 80% of the time redlined, how have you managed to stay out of jail. that and even a B series engine is not going to live long constantly run at redline.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by redzcstandardhatch &raquo;</TD></TR><TR><TD CLASS="quote">no backpressure does not hurt performance in any dramatic way, especially if you felt A LOT of performance loss. the stock manifold on the dual point motors SUCKS, believe me. i've done quite a bit of research into exhaust theory/design, and have created many many exhaust systems.....and a few headers also, and bigger is pretty much always better....if you want to get specific, you can get into the theory of anti-reversion chambers, etc, but that header is NOT what hurt your performance, something else is wrong.. get a tune up and a new O2 sensor, and i bet things will happen. sorry if i seem cranky, i'm not, i just want to re-enforce that no backpressure does not hurt performance, especially where honda's live, which is HIGH HIGH HIGH rpms......seriously. good luck, hope you figure this one out...what kinda header is it?</TD></TR></TABLE>

Sorry, but you are seriously wrong. there is a perfect size and length for every RPM, size and length creat scavangeing action, too big you loose velocity (bad) too small you get restrictive (also bad) bigger is not better, nor is smaller. length also matters in the equation. A 4-1-1 on a D series engine that is not fully built for very High rpm use and not run on the track is not a smart thing to do. All you have is BLING BLING I have a 4-1-1, and that doesn't make your car fast.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sideout &raquo;</TD></TR><TR><TD CLASS="quote">MPFI swap is all i can say</TD></TR></TABLE>


My thoughts exactly. A 4-1 header should shift power slighty away from the low end toward the upper end of the rev range, but DPFI engines have **** for top end so you're not really gaining anything.

What's the point of buying exhaust bolt-ons for a DPFI engine? They can barely breathe in any air, so no need to open up the exit.

 

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

Sorry, but you are seriously wrong. there is a perfect size and length for every RPM, size and length creat scavangeing action, too big you loose velocity (bad) too small you get restrictive (also bad) bigger is not better, nor is smaller.</TD></TR></TABLE>
Correct.

Backpressure = bad

However, backpressure can be caused by both too small and too big of exhaust piping. Too small of a pipe does not allow enough exhaust to escape at once, which creates backpressure; too big of a pipe will slow down the flow velocity so much that the slow moving air will create backpressure.

Backpressure (and engine restriction in general) does shift the torque curve toward the lower end of the rev range, away from the high end.

 

that and the fact that engine redlines about 6,500 and stops making any power (if you call it that) above 5,000

 

If any of you know about exhaut scavenging try to apply it to the equation at hand and relate it to exhaust speed flow. An exhaust can flow to fast (freely) and prevent scavengine. 4-1 has more scavenging than a 4-2-1 but most people make their exhust too free flowing to benefit from the better torque numbers offere by longer primarys. Look into other engines besides a 4 banger, it applies to all.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Targa250R &raquo;</TD></TR><TR><TD CLASS="quote">
Correct.

Backpressure = bad

However, backpressure can be caused by both too small and too big of exhaust piping. Too small of a pipe does not allow enough exhaust to escape at once, which creates backpressure; too big of a pipe will slow down the flow velocity so much that the slow moving air will create backpressure.

Backpressure (and engine restriction in general) does shift the torque curve toward the lower end of the rev range, away from the high end.</TD></TR></TABLE>


exaecctly a properly designed header takes diamete and length into to consideration, to creat a maximum scavenging effect. Bling Bling name brands are not what makes a good header, its design.

However riceboys all seem to think 4-1-1 and JDM is all it takes to equate to fast.

to use a 4-1-1 you need cams, headwork, and lower end work for it to run upper RPM's , which is a PROPER mix of parts, not a HAPHAZARD mix of parts working against each other.

Beside I have built and ran a car that ran 12.41 in the quarter, not the one I have now and it was a perfectly streetible car in 1987. However I got away from that kind of power so I wouldn't end up in jail street racing. and untill last few years stayed away from it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bontke &raquo;</TD></TR><TR><TD CLASS="quote">If any of you know about exhaut scavenging try to apply it to the equation at hand and relate it to exhaust speed flow. An exhaust can flow to fast (freely) and prevent scavengine. 4-1 has more scavenging than a 4-2-1 but most people make their exhust too free flowing to benefit from the better torque numbers offere by longer primarys. Look into other engines besides a 4 banger, it applies to all.</TD></TR></TABLE>

WRONG, a 4-2-1 allows shared cylinders to aid in scavanging, thats why they work so well. Sorry, but you should stick to things you know and this isn't one of them.

a 4-1-1 ONLY scavanges better at very high RPMS, anything lower and it sufferes. Thats why 4-2-1 is better at rpms below 6,000 and the 4-1-1 is better above 6000

However I do agree with your statement that longer primaries help in tourqe. a long primary 4-2-1 makes superiour torque, and a 4-1-1 can not beinifit from the scavanging action of shared cylinders.

Whats wrong with doing a search, this subject has been discussed ad nausium over the last two years.

 

Since there were so many questions and comments i will answer them all.
I have had 2, 4-2-1 headers at different times, i likes them but i figured i would try the 4-1 because i heard of more flow, so i thought i would give it a try.

I am also goin to be putting a d16y8 manifold on this motor with an h22 TB(60MM), which also the head(d16) has been ported polished, head has been shaved, 3-angle valve job, the deck of the block has been milled, also the bottom end has been bored .040. So i wanted to run it in the higher rpms, so dont think i am some dumb rice boy just trying to impress everyone with my neon lights, thats just wrong!

The header i recieved i bought from some dude on ebay, i did not want to spend a lot on it if i knew it was goin to be junk, so in this case, if it does not work itself out, then i know that the 4-1 header was a bad idea for the d. I also did a search on this last night for a LONG time, like an hour, could not really find that much info between the 2. It seemed like not to many had posted there problems or benefits of a header like this on a D-series motor, there were some on a b series but not a d.

I would like to eventually go turbo or supercharger someday on this motor, but that would be a while. If anyone has the info of how to figure out scavenging or flow for exhaust or intake or anyhting like that, send me a link or tell me more about it. I am really starting to get really in depth with the tuning of the car, more power, suspension setup as well.

My suspension consists of 4 strut bars, neuspeed front upper, rear upper, and rear lower, and the 4th is a cheap one off of ebay for the front lower. Tein HA 16 way adjustables dampering coilovers. I did have some suspension techniques sways but i traded them off for some stuff to fix the car a while back, now i just want them back.

Thanks guys for all of your input, i appreciate it,
Matt

 

Ok, i changed the 02 sensor and i went and ran the car in my little test i have, and it hit 65 again. But i was also shifting at like 7000rpms instead of say 6500 or 6200rpm.

i am still running the stock d15b2 intake mani with the stock ecu.

Once i get everything on mentioned above, then i will get a cam to go with it. I think once i get the cam, that will be the BIGGEST increase i will feel. Especially with the port and polish along with the 4-1 header, and that was the reason i bought the thing to begin with. What do you guys think, keep the header for this setup, or go ahead and get a 4-2-1 somewhere?

Thanks,
Matt

 

I say you will bet more usible gains with a 4-2-1 than you will with a 4-1-1