Anyone know of where I can read up on properly designing an intake manifold? ie, size of the plenum in relation to runner length and how it relates to powerband. I've done a lot of research on this and have some ideas down, I just want to confirm everything before I waste time making one and then realize that it was designed poorly. I'm mostly worried about the plenum volume and runner length. But if anyone has ideas about angle of the runner taper, I'm open to ideas on that also.

On a design related note, anyone think there is going to be a problem using 1/8" thick aluminum? It's thinner than the stock cast manifold, but 1/8" appears to be what I've seen in a lot of aftermarket manifolds.

 

maximum boost by corkey bell

 

Thanks, I totally forgot about that one, I'll go look into it immediately.

 

There are bits-n-pieces buried in here that might give you some ideas or more importantly what NOT to do:
http://forums.maxima.org/showthread....ighlight=VANOS

 

You can test your design or stock manifold by hooking it up to a leaf blower before the throttle body and holding the blade open and blowing through. Feel through each of the ports to see how the air flow varies. You'll find some ports flow more air than others. Baffles or restrictors will correct overflowing ports to some that don't do so good.
Doing this method worked wonders on my SOHC VG. Hopfully this will help you too.
Scott~

 

i have this in favorites about plenum design and variable intake resonance

http://www.mecc.unipd.it/~cos/DINAMO...suonatore.html

 

I just got to that chapter, it's the only reason I knew... and I thought you may own it already

 

Thanks for the input everyone, I appreciate it. Right now, I'm leaning toward a large plenum short runner type setup. The motor is boosted, so I don't quite have all the concerns the NA guys do. It will likely look something like the Veilside setup. I will be retaining the stock lower runners simply for ease of fabrication, so hopefully that won't cause too much restriction.

A variable setup is obviously beyond our capabilities, so I understand that we will be compromising. This is more an exercise in design, try a few things and see if it sticks. Just get to play with fabrication.

We do intend to run the TB on the passenger side of the car. We're redesigning the entire turbo setup and I'd like to eliminate the crossover pipe. Basically, turbo to IC and straight into the IM. Based on preliminary measurements, we have the room so I hope this works.

 

thats great! i hope this works for you.

 

Is this just a one time fab or do you plan on producing them if they turn out good?

 

If it turns out the way I want, and it works well, we may produce it. It's too early to say now, I don't want to make a bunch of promises and not deliver. This is more an exercise in design I guess. If it does work, since it faces the other way, it would require a lot of custom piping, so I don't know how market friendly it would be. For most of you guys, it wouldn't be a big deal.

 

but we could flip it around and make it go to the other side if we're s/c'ed. i liked that 2jz one that i saw in SCC a couple months ago that twins turbo made.

 

What is the reasoning behind changing the TB to the passenger side of the car?

 

to eliminate the extra 6ft of charge pipe from the intercooler that ussually runs between the front valve cover and radiator.

 

To save about 3ft of piping. The hood on Shadow's car has no skeleton so there's more vertical clearance. It also leaves us more open to redesigning the turbo location and orientation if you don't have to run the intake pipe back past it.

If we're tearing up the manifold, why not simplify the running. We also have a spare motor and several manifolds to play with if we decide to build a more conventional version.

 

Exactly. I want to retain the turbo where it is right now because it allows me to keep AC, PS and so on. I liked how Hal had his setup on the passenger side, but he had to lose the AC condensor and that isn't an option for me.

I've been looking at my turbo setup for a while, and the sheer amount of piping is just bothering me. So we're going to try and shorten up the charge piping and I have some new ideas about how to run the turbo feedpipes. I basically want to elminate the Y-Pipe and build a real manifold instead. I'd like to keep the turbo feed pipes out of the Y-Pipe area which would allow me to run a large downpipe without losing any ground clearance.

 

Lets say you keep your current setup but take out that extra 6' of piping, what exactly will this give you?

 

I'm hoping for quicker response from the charge piping. Will it work? Who knows, but I want to find out.

I'm hoping for better spool by remaking the entire exhaust manifold, I'd like to run a larger turbo.

 

Shadow,

What turbo are you planning on switching too?

I think shortening the feed/discharge piping is a GREAT idea to help spool, however maybe switching to a more efficient/better turbo would be more effective then running an older T-series turbo with shorter piping. I'd do both, but I'd swap turbos first unless you're sure it's not the turbo.

 

It's a T3/60-1. I do plan on going to a GT series turbo. Not positive on the size yet. But I really think that there are much more efficient ways to run the turbo on a Maxima, so I'd like to find one.

 

I agree, but a T3/60-1 is a horrible choice to use as your baseline IMHO. The oversized compressor and undersized turbine at low boost levels isn't efficient at all.

Depending on your boost level and ultimate whp goal, I think a GT30R, GT3530R, or GT35R would be a HUGE improvement in spool and flow. Most don't like the steep GT-series price, but you're talking about redoing a lot of work, ie piping and fabricating headers, when a simple true GT BB turbo swap would be much easier and might make you happy.

Yeah, the reverse y-pipe isn't the most efficent setup, but with a T3/60-1, you've got bigger fish to fry.

 

This GT3530R turbo would pretty much "drop-in", since it has a T04S style compressor and T3-style turbine:

http://www.atpturbo.com/Merchant2/me...egory_Code=GRT


Just add some coolant lines.

 

You would think that but its performed pretty well even without pushing it past 7psi. The big turbine A/R helps on the small T3 footprint and its less than half the cost of a GT35R. Few other Maximas have broken 300whp at 7psi with the automatic or the manual for that matter. Fresh motor should go in soon and we'll do a few 9-10psi runs to see if it can keep going or if it'll choke off while we rebuild the original. We'll probably end up w/ some variation of the GT35R and much shorter exhaust manifold since that follows the next step up from where we are right now and we can always fab around the similar sized T3/60-1.

As for the fab work, Batlground is assisting so all the fancy TIG welding will be handled by them while we do most of the prototyping and machining.

 

SAE correction can do wonderful things...J/K.

Don't you think that GT3530R would be a PERFECT/easy choice for your current configuration? However, depending on your psi/whp goals, it may be better to go with the straight GT35R.

 

Actually, you can get the straight GT35R with the T3 turbine inlet flange and either the 4-bolt GT 3" or 5-bolt Ford style discharge, so either turbo should be minimal rework.

 

I really don't think the T3/60-1 is all that bad. It's a .81 AR on the exhaust side. I hit full boost several hundred rpm below the T4 ball bearing guys, and my powerband is the exact same. Plus, I'm putting down more power at my boost level than the T4 guys. The Honda guys run bigger T3/T4 hybrids than I have and they're seeing amazing results.

Since my motor went and we're swapping in a new one right now, we're going to rebuild the old one, and I'm going to turn the boost up on it. I feel that some of the minor inadequacies with the turbo setup I have now would really show up when we turn up the boost. What I have now is just what we knew would work when we built it. At this point, we have the resources and capabilities of doing way better and that's what I'm going to try and do.

 

I think the correction factor that night was 1.04. We did like ~290 uncorrected. It's not like I had a 1.20 correction factor like some Maxima dynos.

Bottom line is I don't want to keep my current configuration. What I have now is the easiest way to do a turbo on a Maxima. At this point, I don't want easiest, I want best.

 

I'm more concerned with the slip losses due to the difference between the compressor and turbine wheel diameters then the A/Rs of the housings.

It may appear to work very well, but it's nowhere near ideal unless you have some wheels I don't know about? Try dropping in a GT30 or 35R without changing anything and you'll be surprised at the spool and flow I'm positive. I know preaching to the choir, but T-series especially ones with bad wheel matches just can't be compared.

 

That's not bad at all, but do you have the file you'd share?

I understand, I'd be the EXACT same way with the "best" efficiency only standpoint. I just think piping isn't as bad as turbo efficiency when it comes to spool.

Good luck and I can't wait to see how it turns out.

 

I'll see if I can find the files, it was a year ago. We will be redynoing soon on more boost and a better tune, so hopefully I'll have better numbers to show.

And the piping change won't be just to improve spool, that's actually secondary. The main reason is my total lack of ground clearance. Also, right now I can't really run a bigger downpipe since ground clearance is so bad as it is. If I redo it, I could probably fit a 4" downpipe in there.

I'm aware of the slip losses in running a turbo like that. And I'm sure there are far more efficient turbos. But at the time, it was down to using the T3 hybrid, or a straight T4. And after some research I went with the T3.

 

here is Corey/redmax's current setup...custom x-memeber and feedpipe. as you can see the typical reverse-y design is non-existant. the custom x-member solves the clearance issues, look for a better/cleaner design this summer hopefully.

 

It was 286whp uncorrected to be exact. Pretty hot and humid day in June IIRC. The physical size of a GT35R isn't all that different from our current setup so it's all in the efficiency of the wheels themselves. The big size difference may not be optimal but Maximas are hardly optimized for turbos to begin with. High compression, limited rev band, and engine orientation all conspire against making a short manifold and highly responsive turbo setup. If anything, using the T3/60-1 is a crutch for now but anything bigger will increase lag or cost extensively.

Now if we combine a more aggressive turbo manifold and shorter intake setup along with a nice GT turbo we should be able to provide the best possible turbo setup.

Here's the link for your enjoyment: www.evolution-autodesign.com/shadow7psi.023

 

found this related info.

http://lextreme.com/forums/showthrea...t=M90+manifold