So I had an equal length manifold. It broke. I sent it back to the manufacturer under warranty and the replacement they sent is not equal length, it's a run-of-the-mill ramhorn. Apparently they discontinued the model that I originally had.

So I'm feeling somewhat ripped off, mainly because when I spoke to them on the phone I was told that the new style was also equal length. But I received the manifold today, and it doesn't take a genius to count the 90* elbows and see that it's nowhere near equal length. Not by a long shot.

However, despite the unequal primaries, the benefit is that the bends are broader and have smoother transitions than my old equal-length model. So anyway, which is the greater benefit? Equal length, or smoother bends? I never dyno'd it before, so I'll have no way of comparing before/after

 

just a question but if you never dyno'd it why does it bother you not knowing if there is a performance gain or loss ??? also if you goto bisi or PM him he is the man on smooth bends and transitions.

 

jesus christ

 

Post pic's, theres a lot more to fluid dynamic's than counting bends.

 

^^^Indeed

 

Well I was trying to leave the manufacturer out because they've been so good to me, but I guess I'll have to post pics.

Old style:


New style:




So basically, on the old style, the outer primaries made a sharp turn straight back to the exhaust ports to shorten their length, which is why the manifold was equal length. On the new design, the sharp turn is gone and the primaries are simply built out of unmodified elbows (probably because it's easier to make this way...) so the primaries make a slow gradual turn back to the ports. The result is that cylinders 2/3 have primaries that are 3.5" longer.

 

what are the differences in internal diameter old vs new ?

 

peakboost

 

Equal length is ideal, I still scratch my head when companies advertise ram horns as equal length.

 

The manifold is absolutely fine. For true "equal length" runners,you'd have to place the turbo directly on the bottom of the radiator support facing forward and spend about triple the amount of money that did here. The Peakboost manifold that you have (the newer version is a bit more compact) is based off of a company called Kooks back in the early 90's and has been more than capable of over 900whp with a high level of effectiveness. I really don't think anything is going to affect you (fluid dynamically speaking) for this new version. Unless your purpose is a fully-sponsored drag race application, your 350-650+whp car will do more than fine with what you have there.

Put it on, use it, drive and enjoy, for heaven's sake.. Life is too short to get worked up over smaller things like this for an application. Next time, if it doesn't fit your liking, you could always make your own...Just a thought

 

I agree with TheShadon. I tried ram horn, top mount, cast manifold for 600WHP. I did not notice much on the dyno or the street. Top mount had better top end.

Put the bloody manifold on already.

 

I've never cared much about peak numbers. What I care about is squeezing out maximum power from minimal boost. You're talking to the guy who has spent 100+ hours with carbide bits and cartridge rolls port-matching every imaginable union of intake/exhaust parts on his engine. I've spent over $2,500 in headwork alone, sending the head to various top-name machine shops to have it re-tweaked. I've spent over $10,000 on this d-series engine.

And I've never gone above 8psi. So no, I don't care about peak numbers. What I care about, as I think I stated in the original post, is which style makes more power. Perhaps one is better in the midrange but dies out up top. Or vice versa. Or maybe the difference is immeasurable. Or maybe nobody knows the answer.

At any rate, of course I'm going to install it. I don't have any other options. Of course, I'll need to break out the carbide and port it out first...

 

Based upon the type that you're utilizing in the first place, Top end seems to be your MAIN focus, since it seems that "more power" is your biggest concern. That could be easily construed to believe that you do care a bit more about top end "peak numbers" as you so colorfully put it. You can port match until the carbide bit breaks, but it appears that you're taking a rather Naturally Aspirated approach to a boosted application in which forced pressure into the intake manifold is utilized. Scavaging for air from your methods isn't a requirement at all if you're using an efficient turbocharger that is giving you the powerband that you're looking for. You'd really be wasting time pulling out the carbide to port out this manifold to try and extract more efficiency. In fact, you actually WANT some turbulence to enter into the turbine housing to keep the velocity of the exhaust gases up to effectively maximize the use of your turbocharger.

This is similar to those that port n polish their cylinder heads (i'm looking at mainly B-series vtec heads) when it comes to forced induction. On several bench tests I've made between to 2 (one ported by Portflow, and the other stock) there was only a 20cfm difference the MINUTE you stuck a turbocharger on the engine.

Hey, its your carbide bit and car, do as you will. As long as you feel assured that your methodology is what is best for you, go for it. no one here is preventing that. But to say that you got "ripped off" because of something that isn't as "Equal length" as you imagined, is rather..shall we say, naive.

 

that deserves a golf clap or something lol

 

for all these years that some people Just like to mess with things that don't need messin' with...

 

I'm straining to remember the "run-in" we had, since I rarely have confrontations.

But, in the 10+ years I've been in this industry I've tried as hard as possible to please everyone to the best of my ability and can't expect to see eye to eye with everyone. I'm sorry if this was one of those cases

Here are a few others opinions:
https://honda-tech.com/forums/showth...ghlight=6years

 

What are the conditions of the warranty? If the conditions are not clear, simply ask PeakBoost to make you that manifold again or repair the one that broke.

By the way OP, you're absolute nuts. $500 on the dyno probably would be better spent than $1000 on head work.

 

Top end != peak numbers. How about this, maximum area under the curve in between shifts. Obviously I'm shooting for top end power. You aren't going to make low end power from 1.6L.

As an engineer with OCD, I'm definitely taking the **** approach. I won't deny that.


I disagree.


Eddy currents reduce velocity. And the overhanging turbine flange is going to create small recirc. zones.


That's 20cfm more than you had before.


Nothing was "imagined," I was told I was getting one thing and I received something else. It's not what I paid for.

 

Wow, lots of drama with Peakboost I guess? I don't think I've posted in FI for a few years now. They've always been really good to me. I didn't even have to tell them what happened, they received the manifold I sent back and shipped a new one ASAP. Customer service was A+ in my book.

Btw, by "porting" I'm referring to beveling the overhanging turbine flange, not grinding on welds. I don't go anywhere near the welds.

 

can you explain why you would get "eddy currents" insides a turbo mani ???

i was under the impression that eddy currents dealt with electricity not air flow ?

 

I suppose that's what separates the engineers from the people who looked up "eddy current" on wikipedia. In a nutshell, it means that flow isn't laminar in the real world. And given the collector merge angle, I'd say turbulence is unavoidable anyway.

 

you do realize that when you say eddy currents i think dyno correct ? maybe you should learn about using one

oh PS im an accounting major and i found what you meant by "eddy current" the way you decrease that is by making the "spike" extremely pointed, narrow, and even ( sorry if i dont know the tech terms ) in the merge collector

 

20 cfm is NEGLIGIBLE in the FI world dollar/benefit. As a consultant for Garrett turbochargers for over 7 years, I kinda have an idea. We could swap brain pans all day in the realm of engineering and fluid dynamics, but it does no good. What may look great on the paper does not necessarily translate into usable results. Some exhaust turbulence is needed in order to get a better boost recovery.

Again, if you want equal length the way you're describing, just learn how to weld and make your own. You may find that you have something marketable to sell to the community.

GL w/ whatever you feel is best.

 

20cfm was your number. The radical porting I did actually made a huge difference on this d-series head. Out of curiosity, how do you test a turbocharger on a flow bench?

Anyway, I don't design for Honda anymore. I've moved on to... more lucrative markets. In fact, I have to give props to anyone who's still in this game, because the money comes so much easier with other makes.

And Ken, I sent you a PM listing my long-winded woes, but you must not have seen it. I guess no one has adjusted to vB yet. I'll call you tomorrow.