Modified l28et manifold

[Tony D]

I didn't see much discussion just acerbic commentary.

 

When the aftermarket heads make the 850 HP at 26psi that the good old L-Series N42 Head did waaaay back in 1983...maybe I'll take notice.

 

But till then, it's just sounding like beating one's own chest over trodden territory.

 

Most of this is done because we can... making a negative statement like you're wasting your time is not a discussion, it's chucking stones. Especially when we can see here clearly the resultant response. Jab, jab, no discussion. I think the O.P. handled his last thread in the negative exactly the right way: I'm not picking your decisions apart, don't do the same to mine, thanyouverymuch! Which is a fair assessment of what was happening. The merits of the project were not discussed, the decision was put into question, and that goes along the lines of 'What is BEST'...

 

Asking for rationale or something else is one thing, chucking a negative attitude into the mix on an otherwise upward beat post is something altogether different and not needed. I didn't see any 'constructive' criticisim, just a terrible misreading of post context, and total disregard for the O.P. originally stated intentions for the build. The decision to do the build in the way it was done was basically called ''not the best''...

 

Like the forum rules say: "There is no best" coming in with factual commentary after starting on a premise totally fabricated out of cloth is just bad form, regardless of what the 'facts' may be.

 

I took it for what the O.P. stated he wanted to do: a study of the intake to meet his set criteria. I simply came in to give some rationalised numbers so there would be a clear understanding of what could be expected, and where to expend efforts in the future. Nowhere did I come in with an intimation that it was a waste of time. Frankly any of this work is a waste of time and frivolous, there are much better things we ALL could be doing for humanity with the money, time, and effort.

 

That all being said screw the rest of the world, I'm going to work on WHAT I WANT TO WORK ON: My Z Car!

 

The manifold looks like it's progressing nicely, and I for one would be interested in the results being quantified. For ANY of the manifolds being chucked out as superior, inferior, or a waste of time. NUMBERS not opinion sway my judgement when someone undertakes a project. And for that, the best course of action is help along the way and see what comes out at the end of it. That, I would see as a positive way to approach this build as an observer (and I think a couple of people have!)

[Zmanco]

Wax, I suspect there are many others like myself who have subscribed to this thread because 1) we know that the stock intake manifold is a performance limiter, 2) are glad to see people like you taking a stab at ways to improve it, and most importantly 3) for many of us, owning our Z is just as much about the journey of experimenting and learning as much as it is about the ending when we have an improved car.

 

Please keep updating us with your progress!

[woldson]

Looking good!

 

Are you going to get it dynoed?

[wax]

yes i will be getting it dynoed

I have a friend who has done alot of tuning here in australia and has bene shipped all over the world just to tune in race cars ecu,s

I have been extensivley talking with him about what ecu to run etc.

When its ready to go i will going to a dyno with him.

My main goal is to have 350 at the rear wheels not for all out power.

But i would like it on the least boost i can run , hopefully not more than 15psi but if i have to go to 18 then i will live with that.

 

Thanks for the heads up guys. I am enjoying playing with the manifold and seeing what i can get.If i find it to performance limiting then i have a side draft manifold already and i will make an intake system based on that

[Ben260Z]

wax

Yes iam running a crank trigger,3 coils, waste sparke on a haltech e6x.

 

Keep posting, i have 6 new forged piston ready to go in the engine when i got the time , so later this summer we will see how much hp we can make with this manifold, i have only driven it 1 hour but it runs good.

 

I was worried about throttle respons but it was fine, i have an overkilled throttle body (90mm).

[wax]

Ok good to know

Yeah i am not sire if to buy forged pistons or not

I know it gives a big safety margin and thats a handy thing

Im thinking about a 70mm throttle body on mine

I will just see what comes along for the right price , if i can get one that has an air bypass on it already that would make life nice and easy

[Daeron]

It sounds to me like the overall point 1fastz was trying to make is a warning: if you do indeed have a 35mm diameter ball bearing that hass full clearance to run through those runners, Beware!! Our best data indicates that you may have hogged your runners out to 1mm or less in wall thickness!

 

And then there was a wee bit of tonyd's acerbic commentary on both sides after that. But the point should not be missed; it is one of the first things I thought upon reading this thread through the first time myself.

 

If you ask me, a 35mm intake runner on an L28ET is a nice "Anti-reversionary step"

[Challenger]

I have to agree also on the runner thickness. Might consider drilling a couple holes through the runners to see how thick it is. Seems like you could weld up the holes pretty easily if you find the thickness is fine.

 

Also concerning flow on the tb, Im assuming that anything larger than the stock Tb will flow plenty of air through the manifold. Does that mean (if thats true) you should look for a tb that gives the best flow into the intake, rather than just something really big?

 

Also when working on the angle of the Tb opening would using the blowing end of say a shop vac work on finding the best angle for proper air distribution to each runners?

I just remember cleaning up a manifold with a shop vac and I thought Id see what happens if I stuck the nozzle over the TB opening. I really noticed 1 and 2 had very little flow.

[wax]

I would say on a stock manifold the flow through number 1 and 2 would be bad at least.

As far as throttle butterfly yeah i agree looking for the best flow into the manifold would be best of course.

I am looking at one of a xf ford falcon. it wil have sufficent flow as well as have the ac valve built into it

That just means one less thing attached to the manifold

 

Im not sure where you guys are measuring your manifolds from but the thinest my manifold is at any point i measure is 39.2mm

Thats a wall thickness of at least 2.1mm at the thinnest point.There rest of the manifold is wider

 

I am sure it will meet my requirements

Please read back on the 2nd page where i am looking at a projected hp figure of about 350 whp

 

Im not trying to make 500 plus from this engine. the manifold is being modified to look good as well. If i was just after air flow i would have made a straight runner manifold, however i think they look awful and am trying to avoid that look at all cost.

I want people to look at my engine and go that looks cool not um, nice wheels

[Daeron]

OP: I wasn't trying to criticize by any means, just point out the important thing from 1fastz's post: wall thickness. I cannot seem to dig them up right now but we had a thread that had the runner diameter and average outer diameter of many of the different manifold castings, and 39.1mm OD sounds larger than the data that have been accumulated thus far (Someone PLEASE correct me if I am wrong! I couldn't find the right thread!)

 

Not trying to call BS either; if you measure an average OD of 39mm thats freakin great, but I am trying to explain where 1fastz was coming from. 35, 36, 37mm is what I seem to recall the maximum OD of the manifold runners being according to the info posted in that thread. Obviously it was by no means complete or independently verified.. but you see what I am getting at? It seems your manifold is larger than most.

[wax]

Ok here is some pics of me with my digital calipers. As every one can see its clearly over 39mm every where i measure

I am unsure if we get different manifolds then you do in the usa but i would very much doubt it

Im not sure if the non egr manifolds have smaller runners or not

This was an egr manifold before i removed it.

On another note i have been building and porting race jetski engines for over 15 years as well as other forms of motorsport. Im not about to grind something to a 1mm wall thickness ever

[wax]

On another note i found this while searching throught this site

 

I emailed Lonewolf for flow data on their Nissan heads and this is the reply I got:

 

We offer to levels of porting on the nissan intakes. The first one invloves porting of the runners and TB opening and getting as far into the runners as possible. The second option invloves cutting the plenum off and porting the manifold from both sides of the runner to do a much more thorough job. We've been able to pick up over 90cfm on each runner when flowed individually. The bottle neck lies in the TB opening. You can only make it so big due to limitations to the neck of the manfold. We flowed a stock intake, a option one ported intake and then a cut apart and ported intake but we recently moved and I'm not able to find the flow data. I do remember that we picked very significant flow when the intake was cut apart and ported. It was around 270cfm per runner after porting. If I'm able to find my records, I'll let you know and e-mail them to you.

 

Mark: What he didn't say is if the option 2 (cut the runners off) was the $350 option quoted on the web. I'm going to guess not, for that price. If it is, I think I'll jump on that option. Much cheaper than their custom intake at $700...or maybe I'll choose DYI we'll see about $$ and time.

[woldson]

I can see from your experience that you probably would have not been dense enough to have a paper thin manifold, especially boosting.

 

Way to stick to your guns in a adult manner. Cheers!

[HowlerMonkey]

Cylinders 1 and 2 will be happy with that geometry.

[wax]

Thanks

yeah i am hoping they will flow alot more now with the manifold modified

The way they flow on a stocker is rubbish. It will be interesting to see what the dyno comes back with

Thats a long way away before it gets there however

[garvice]

Thats a long way away before it gets there however

 

Well we could always put it on my car and see how it compares to a stocker. LOL.

[wax]

You know what i wouldnt mind seeing that happen to see what the difference is.

Call me if you like.

My number is on my website. www.waxracing.com

[garvice]

No worries, we will talk once you get it all ready.

Mind you my head is stock and my throttle body is via linkages, so it may still require us to do a bit of work to get it working.

 

I'll also let you know next time I am down the coast.

[Tony D]

Flowing 270 per runner would outflow most race ported L28 heads, making any aftermarket manifold unrequired...

 

I think the important thing to come away from the 'runner diameter' discussion is that things in the US Market may have been quite different indeed than what was available in Japan and worldwide. I have seen people swear there were no N42 Heads on 82 280ZX's... Well in Japan there were... And all those import engines sold years ago? Not one came with a P79 or P90... Japan didn't get them! And the N42 casting? Different than what we got here due to different emissions requirements.

 

Point being keeping one's mouth shut sometimes is the best course because you don't know all the combinations possible---the best course may be to clarify the situation with something like 'here we've found only 36mm OD runners, what's your runner O.D. if you plan to go to 35mm ID?'

 

If you read the FIA Homogolation Sheets for the L28E, the manifold specified I.D. for the runner was 35mm, as I recall. Might say something about what they were designed to take?

 

And worst case, you weld at the last portion of it.

 

Really, 35mm at the gasket surface would not be the ideal setup anyway, unless you are a big turbular log manifold afficinado... a tapered runner somewhere slightly larger or possibly 35mm ID at the PLENUM end, TAPERING to a given diameter at the gasket surface would be nice for velocity. And then as Daeron says: having a head ported to 35mm would leave "a nice anti-reversionary step at that point"---which may even have merit in a Turbo Engine.

 

As for 350HP at 15psi... with the right cam, turbo, and porting on a stock manifold 350 to the rear wheels should easily be accomplished below 15psi. To bring out JeffP's engine in different tunes, he was making 380Ft-Lbs of torque to the rear wheels at 4500rpms at 8.39psi of boost some years ago. His last run with a bone-stock L28ET bottom end was over 300RWHP at 10psi, and 460+ around 20psi.

 

My stocker with blowthrough mikuini carbs was in that general area when I ran 17-20/21psi (EFI has the advantage hands-down in this regard, though I wouldn't complain too much about 17mpg in that trim in daily driving!)

 

The goals as stated originally are eminently reachable. The big point I was making was the goals were stated clearly enough that it was more a design exercise than anything on the manifold, trying to improve what was there without an aftermarket piece. Hell, they are reachable without porting the stock manifold!

 

As an option to cutting apart and porting a manifold, always remember Extrude-Hone makes a quick job of it as well. I mean, in this application how much flow do you really need---and that is the key question. Hands down the answer is 'nothing' when you can make 350 on boost alone. So at that point arguing over what the engine 'needs' becomes a bit foolish. It doesn't 'need' any of it. That he wants to do it is all the justification he needs to proceed. Who am I to give anything but encouragement. The more people making 350+ on stock components, the more people who can combat those insisting the 'need' for this component or that!

 

Perying on the ignorant can be seen as bad marketing, or great marketing...in either case, it's not marketing I would choose to be party to, regardless of the customer or vendor!

[boardkid280z]

Great work on this project! Very interesting to see all the different takes on manifold modification and performance enhancement.

Have you done any measurements or estimated what the resulting plenum volume is going to be? It seems like that was one of your initial goals.

What thicknesses did you end up using for the top and bottom plates? And will you be able to modify the throttle linkage or will you be going 'cable'? I have always like the stock 'solid' linkage on these cars.

 

Nice work wax, keep it up. Excited to see what your resulting flow numbers will be too.