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Old 01-09-2008, 08:08 PM   #1
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Default Help with intake!

EDIT:
Alright well since the other topic was closed, i'll continu the discussion here, so i'll repost what i psoted there, to try and see if i could get some more opinions

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But then it still doesn't give me an answer...
This is my situation, i'd basically like to have opinions on what people think of this exact setup;

I was looking into getting a CAI for my 92 SSEi. I want good looks as much as performance...so i was looking into this:

http://www.spectreperformance.com/#CATALOG.8808 ** I suggest you lower your volume on the speakers, as the site has some crazy sound effects + music.
You Have to go in the ''Catalog'' section top left.

First off, should i go for a 3.5'' direct or should i reduce it to 3''?
With whatever answer you have to this question, go to either the 3'' polished aluminum or the 3.5'' polished aluminum.
P.* - There is the 3'' Chromed pipes, but those are made of Chromed ABS, plastic, so i'm guessing that'* no good?

Then, its pretty straight forward, i'd take the 60 deg bend, with 2 or 3 4'' tubes( i haven't made any calculations yet). Then if you go in the accessory section, or look up part# 9406, i would use that to clamp.
I looked into it closer, and polished aluminum is nice, good with heat(or at least better than other matirials, light, smooth inside, and witht that clamp is doesn't look like there is going to be any obstacles for the air flow inside...

Basically this is what i would like to do, as it sounds like a good/nice looking CAI.
I would match it with the RX-4750...
I MIGHT just buy that non-insulating reflective wrap-around that willwren nicely tested, but that would probably be a little later.

I would just like to know if you think this is good enough or if it'* complete garbage....just keep in mind that i will most probably not be doing any serious drag racing, that this is strictly for personnal use, and for myself to enjoy it better .

I had pm'ed willwren directly about this, but he'* right, i should let everybody know about this issue as i'm positive i'm not the only one inquiring and having issues with this.


I really, really appriciate your help and time!

Thank you so much!!!

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Old 01-09-2008, 08:17 PM   #2
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Topic split.

you should get better help this way
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Old 01-10-2008, 09:56 PM   #3
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thanks peter! haven't got much reply though hehe..
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Old 01-10-2008, 10:07 PM   #4
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one thing I can say it go 3" NOT 3.5" as the TB is only a 3" to begin with.
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Old 01-11-2008, 08:47 PM   #5
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are you sure? i thought the TB was a 3.5'' on the 92...?
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Old 01-11-2008, 11:15 PM   #6
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Quote:
Originally Posted by rolley
are you sure? i thought the TB was a 3.5'' on the 92...?
no, pete is correct. the 94-94 l67 had like 3.68", but ur 92 is 3"
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Old 01-12-2008, 03:22 PM   #7
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1992 SSEi white here. I'm thinking about doing the same thing. I'm debating upon the polished aluminum or the Chrome ABS. I'm not sure which would be better. Mainly members say the aluminum but there are some members with the Chrome that state that it stays cool even in the summer.

Also does anyone know what the dimensions are from my TB to the 3'' pipe? 3.5 to 3?

I'll probably make a custom heat shield out of Plexiglas. Speaking of which. I have seen members put writing on their Plexiglas. How is that done?
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Old 01-12-2008, 08:48 PM   #8
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Quote:
Originally Posted by Arakor
1992 SSEi white here. I'm thinking about doing the same thing. I'm debating upon the polished aluminum or the Chrome ABS. I'm not sure which would be better. Mainly members say the aluminum but there are some members with the Chrome that state that it stays cool even in the summer.

Also does anyone know what the dimensions are from my TB to the 3'' pipe? 3.5 to 3?

I'll probably make a custom heat shield out of Plexiglas. Speaking of which. I have seen members put writing on their Plexiglas. How is that done?
Yea same here i'm not sure which would be better...the Chromed ABS is a little cheaper too.
Like Pete said, our TB are 3'' anyways, so keep it straight 3'' all the way...

And about the Plexiglass wirting, if i'm not mistaken that'* willwren who started and he did it with laser engraving
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Old 01-13-2008, 01:48 AM   #9
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3 inch both ways, nice. Well I went up to Autozone today and was able to look at both pipes today. They had both on the shelf. 39.99 for the Chrome ABS. 44-45 for the polished aluminum. Personally I think the Chrome ABS looks better, but I'm hesitant about rejecting the metal for it.
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Old 01-13-2008, 12:02 PM   #10
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Plastic (any form) is by far the last option you should choose. Rather than that, I'd suggest perforating the stock airbox and dropping in a replacement K&N.

The 'ideal' CAI should be non-plastic pipe (3" only for 87-94 non-supercharged and 92/93 supercharged), good quality filter, effective heat shield, and cool-tube insulation on the pipe. The reducer/coupler at the TB should be flexible silicone.

Intake insulation:
http://www.bonnevilleclub.com/forum/...ic.php?t=54883

Here'* my old SSEi intake (from before I went to a FWI last winter) currently living under the hood of my 95 SLE:

Name:  DSC00501.jpg
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My heat shield isn't complete by design. When I built this, I intended to feed it from an alternate source to prevent hot engine bay air from entering:

http://www.bonnevilleclub.com/forum/...ic.php?t=16005


The filter:
http://www.bonnevilleclub.com/forum/...pic.php?t=8497

More reading on intake sizes:

Quote:
Originally Posted by willwren
It'* not the CAI vs. FWI that'* the issue. The other topic was regarding a 3.5" FWI. If you want a FWI, go 3". It'll have to be custom, of course.

And what TB/Top are you talking about swapping? How can you accomodate more flow with a swapped TB when your car doesn't flow the air to begin with? What I'm getting at is your natural flow numbers. Your TB has a 2.25" throttle plate, and your runners are designed to flow a specific amount based on your bore and stroke (displacement) and the RPM'* your motor is expected to turn at, as well as the lift and duration of your valves, head geometry, etc.

A good comparison would be L27-L36. The bore and stroke is the same, but the L36 rev'* and shifts at higher RPM'*, increasing peak flow at the shift or redline over that of an L27. This is why the LIM, UIM, and TB on the L36 flow more than an L27.

Unlike the Gen2-Gen3 swap from the 91-93 L67'*, I'm not familiar with a directly swappable TB for the L27 that would allow you to do this, and then your UIM and LIM are still a restriction, not to mention the stock cam and 1.6 ratio rockers.

Even with 1.8 ratio rockers on an L27, I'd think a 3" CAI or FWI would be more than sufficient to supply you. I'd be thinking about PEM'* long before going with a bigger TB.

The problem lies in producing laminar flow. Getting the air moving in a uniform direction and laminar manner increases velocity, which is what you need to feed your engine efficiently, and be able to read the volume of air passing the MAF sensor accurately. A 3.5" intake could actually hurt you, as it can flow far more air than your engine can demand. Some of that air is going to 'mill around' looking for a place to go, changing direction, and creating eddy currents as it necks down from 3.5" to the 2.25" throttle plate. As the air changes direction, your MAF sensor loses it'* ability to read the flow accurately, throwing off your air/fuel ratio.

By properly sizing (no, I'm not aware of any magic calculators or flow numbers to nail this for you, but common sense and logic can get you close) your intake, you can actually get more flow through a smaller properly-selected size than you would from a larger one.

Too small=bad
Too large=bad

But there'* a little wiggle room for X=good somewhere between them.

I recall a FWI someone here put together last year. He didn't have a 3.5" flange on his filter, so he used a 3" filter, stepped up to a 3.5" tube, then necked back down to the TB.

Would your garden hose (say half inch inside diameter) flow any better if you inserted a section somewhere in between the ends that was 3/4" inside diameter, then necked it back down? No. In fact, it'll probably flow slightly less because of the turbulence created at each diameter change.

I'm not saying this is what you're intending or asking about, but it'* a better way to visualize a diameter change in an intake. Your really want no changes in ID (inside diameter) until you get to what you can't control.......the neck down transition inside your TB from the bore to the Throttle Plate.

Hang on a few, I'm going to crunch some ratio'* that may help you decide.......
Quote:
Originally Posted by willwren
Let'* say an L27 flows about 335 cfm @ 5000 rpm'*.
For comparison, let’* throw in a 94/95 L67 (chosen because I have the flow data on the Gen3 M62 handy, and not the Gen2). The L67 will flow roughly 40% more at 5000 rpm’*. (Someone please check my math on that 335cfm please, I’m thinking way ahead of my typing…..number accuracy isn’t guaranteed, but these are good for comparison for the time being).

*****Important thought to keep in mind*****
The M90 doesn’t actually flow more than an M62 in our application. Our bore and stroke as well as compression ratio’* amongst the various L67’* are the same, and the M62 simply spins faster to flow the same amount per stroke as the slower-spinning M90 due to the diameter difference in the rotors. The M90 is more efficient in moving the same amount of air the Series 1 moves, making the boost charge a lower temperature. Comparing stock-stock, the Gen3-equipped M62 Series 1 and the Gen3 equipped M90 Series 2 will flow the same amount of air at the same RPM.

Back to our regularly scheduled programming…….

So we have a 40% flow difference between the L27 and the Gen3 M62 equipped L67 at 5000 rpm’*. The throttle plates are also different. The Gen3 M62 TB on the 94/95 L67’* is about 25% larger than the L27. Not 40%, but it doesn’t need to be if we’re forcing the air through instead of ‘naturally aspirating’ it. There is a downside to this (heat) but that’* another topic altogether.

Now let’* step back a bit and discuss ‘what works’ based on the experiences of our members. Back in the day, ADTR calculated the ‘ideal’ intake pipe diameter at 3”. This was based on what MOST of us were flowing. A lot fewer of us were modified very much if at all 4 or 5 years ago. I ran that 3” intake all the way through last season when I discovered I was at the point where I was probably capable of out-flowing it. Knowing I was going to port my heads, change my rocker ratio, and a few other things, and knowing I was already flowing more than most mildly modded Series 2 L67’*, I stepped up to the 3.5” FWI based also partially on INTENSE’* research. If it’* a good intake size for a modded S2 L67, and I flow as much or more than some of them, it should be a good size for me. OldBlueEyes also did some back-to-back comparisons with a 3” CAI (good quality) and a 3.5” FWI while running a 3.4” pulley on a S2. He was actually able to feel the improvement of the 3.5” FWI.

If we can A$$-U-ME based on our collective experience and that of some of our vendors that the L67 market is well-served by a 3.5” intake, and we know the flow differences between the L27 and L67 (stated above) we can draw some rough conclusions and see what comes out.

Using simple algebra to see what the ‘suggested’ pipe diameter at the L27’* 335 CFM flow would be if the 450CFM pipe is 3.5”, I came up with 2.6”. Don’t go to the bank on this just yet, it’* just the first step in comparing them and to prove a point.

Now let’* look at the AREA (determining flow capability) of a 3.5” tube:
9.62 is the answer. Keep in mind the Area is the important calculation here, not the diameter of the tube due to the pi function……as a comparison, a 3.5” tube is only 16% larger than a 3” when comparing diameter, but not when you correctly compare area, which is what we’re interested in).

For a 3” tube, the area is 7.07.

Flow difference? 36%. Pretty close to that 40% number right?

We’ve obviously not taken into account the VE numbers or anything else like that, and I don’t have the time right now to go into it, but the whole point of this exercise was to come up with some kind of guide for determining the properly sized intake for an L27. There’* a lot of different ways to do this, but based on what I just ran through quickly, it looks like our ‘standard’ suggestion of 3” CAI or FWI for basically stock or mildly modded cars is about right. Even stock Series 1 L67’* (particularly 91-93) are probably very well suited for the 3”. There could be some gray area here, and calculating where the L36 falls is another question as well, although we know they flow somewhere between the L27 and L67 at WOT. Go 3.25” on those. (joke there, not going into that discussion today).

/class
Quote:
Originally Posted by willwren
I have 5 Throttle bodies in my posession. 92-94 L27, 92/93 L67, 94/95 L67, 95+ L36,
and 96+ L67.

jr's3800 asked me to make some throttle plate comparisons, and I found an interesting
item in the process.

The 94/95 L67 TB actually should flow slightly better than the S2 L67 TB based
on diameters (flowbench testing has not been done to determine any flow differences
due to MAF housings, but they look IDENTICAL in this regard).

http://www.williamwren.com/bonnevillepics/TB1.jpg
Top row: 92-94 L27, 92/93 L67, 94/95 L67 (note modified throttle shafts on two of these)
Bottom row: 96+ L67, 95+ L36

http://www.williamwren.com/bonnevillepics/TB2.jpg
Stacked foreground to background by size

http://www.williamwren.com/bonnevillepics/TB3.jpg
Stacked by size from the side


The numbers

The 92-94 L27 throttle shaft is modified as is the 92/93 L67 in these pics. Just something
to compare to.

Bottom line is that we've found yet another reason why the 94/95 L67'* seem to be
posting very similar track numbers to S2 L67'*.
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