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Cold air Inlet(s)

Started by WGB, 05 July 2008, 03:59 AM

WGB

A post on the M-100 site yesterday about re-siting the battery in the boot for an LPG installation in a 6.9 led me to again contemplate using the twin intake 560 aircleaner and ducting that is gathering dust in my shed.

It is not difficult to mount the battery in the boot, arrange an earth and run an appropriately sized cable through the floor and along under the car to the starter motor. I have a separate feed to my seat heaters but that would not be difficult to link up. The most difficult part would be making a suitable cover for the battery in the boot and arranging safe drainage of acid laden fluid.

I even have a spare 116 battery tray although the original could be used.

Another suggestion has been to use the smaller 66amp battery ( I have a dead one lying around to use as a template) which might give enough clearance to allow a duct to get to the front of the car down the right hand side of the motor.

My questions are :-

1) Can the 6.9 be reliably used with a 66 AH battery - especially when only used once per week.

2) Is the increase in performance sufficient to warrant the effort and further removal of the car from originality - although it would be easy to reverse if needed in the future, particularly if the battery is not re-sited.

Bill

craigb

I an't help with ost of your questions but I do know fro  rally days that sealed battery boes are readily aailable           and part of y keyboard sees to hae gone to sleep so hope you an fill in the issing letters!!!
1980 280s

CraigS

Here are your missing letters, so just drop them in where you feel like it

C M M Z V M M V M
[url="http://s109.photobucket.com/albums/n77/Aegeanfoods/My%20Cars/"]http://s109.photobucket.com/albums/n77/Aegeanfoods/My%20Cars/[/url]

Big_Richard

#3
.

Mforcer

If we consider that the twin snorkel air filter was introduced by MB for the 5.6L engine, I would assume that the same benefits they discovered for that engine would be available to any larger engine by the twin snorkel. We do need to assume that the flow capacity of the twin snorkel exceeds that of the original single snorkel.

Will the performance be better? Noticeably better? Only you can tell us after testing  :)

You will also need to consider, other changes to the airflow into the air filter and around the engine bay are just as likely to have a negative affect than positive on performance. Moving the position of the intake into a lower pressure region of the engine bay will reduce the air flow into the engine. Similarly, altering the air flow into or around the engine bay will alter the location of low and high pressure regions. Doing this will need to be thoroughly tested before making any permanent changes. My research on this topic only revealed the time effort needed to test this and then for only marginal gains from a luxury car.

I can't imagine a smaller battery having a negative impact on air flow into or around the engine bay. Running piping around the engine bay may have an impact.

In the end, what is the purpose of making these changes apart for change's sake? Our cars will never be the fastest or the best handling on the road today.
Michael
1977 450SE [Brilliant Red]
2006 B200

craigb

Thanks for that, I know which keys to fix now!

On the cold air thing, Greg who is a regular contributor to the NSW MB club forum is the only one I know who has done this and noted the difference. He did it on a 107 350sl and if you do a search on that forum, I recall a detailed account. From memory he just cut the end of the air cleaner inlet and ran a hose to the front, so different to M100 but his findings may help in the decision process. If the smaller battery allowed you to experiment without altering too much, then you can assess how well the whole thing works and then do a battery move if it seems necessary later.
1980 280s

WGB

I tried fitting the 560 aircleaner today but as the RH horn fouls on the air-conditioning hoses in a 6.9 that is the end of the discussion for me.

Definitely in the too hard basket but looks quite easy to do in a 450 using the original 560 plastic hoses with right angled end pieces and building a screen covered opening in the small panels beneath the headlights.

In the meantime I still have a spare K-Jet air-cleaner and possess some metal fabrication skills so might try to build a copy of the rare AMG air-cleaner represented here.



Probably won't do much for the airflow but will be an interesting addition.

Thanks for the replies guys.

Bill




CraigS

Quote from: Patrick Bateman on 05 July 2008, 09:24 PM
Quote from: CraigS on 05 July 2008, 10:36 AM
Here are your missing letters, so just drop them in where you feel like it

C M M Z V M M V M

Battery BoZes ?

Obviously my keyboard is not working right either ! I wrote them down right - just couldn't type them !
[url="http://s109.photobucket.com/albums/n77/Aegeanfoods/My%20Cars/"]http://s109.photobucket.com/albums/n77/Aegeanfoods/My%20Cars/[/url]

Mforcer

Quote from: craigb on 06 July 2008, 05:32 AM
On the cold air thing, Greg who is a regular contributor to the NSW MB club forum is the only one I know who has done this and noted the difference. He did it on a 107 350sl and if you do a search on that forum, I recall a detailed account. From memory he just cut the end of the air cleaner inlet and ran a hose to the front, so different to M100 but his findings may help in the decision process. If the smaller battery allowed you to experiment without altering too much, then you can assess how well the whole thing works and then do a battery move if it seems necessary later.

I have spoken to Greg (also a member of this forum) some time ago about this and have inspected the modification to his car and he has indeed noticed improvements to the running of his engine. Greg's mod does indeed have the intake positioned at a high pressure region, next to the radiator. Unfortunately, the differences between the 107 and our 116 do not allow us the same modification.

You will note on a 126, from which your twin snorkel came from, that the intake tube runs to an intake in front of the radiator. This would seem to be perfect but I have not seen how this is possible on our 116.

To expand on what I wrote previously, one of the factors to determine the improved air flow into the engine is the air pressure difference between the engine and the end of the intake. If you lower that difference from its current level, you will reduce the airflow into the engine. You must find somewhere with a higher air pressure and locate the intake at that point. At the front of the car, next to the radiator is a high pressure region. The air pressure above the hood will likely be a lower air pressure than under the hood and unless you position the intake into direct airflow above the hood line, will result in reduced airflow into the engine. To make matters more difficult, air pressure around the engine bay and around the car generally will change with speed. You would need to determine at what speed you want to achieve the greater airflow into the engine.

Considering ventilating the engine bay, this could reduce engine bay temperatures allowing for colder air into the engine but again would alter regions of high and low pressure under the hood. These pressure regions would need to be tested to ensure a performance enhancement rather than detriment.

I do hope that I have not put you off from attempting a cold air intake and I know you are more than capable of working this out. I know it just needs to be done right and I have seen no evidence to suggest that anyone has done it right, yet. I would trust to some degree that AMG knew what they were doing with their long, thin second snorkel. But then if they did, why haven't we seen more of this mod?
Michael
1977 450SE [Brilliant Red]
2006 B200

Papalangi

As for the battery in the trunk trick, I'd go with the Australian version (if there is such a thing) of an Optima battery.

http://www.optimabatteries.com/home.php

They can't spill since they don't have a liquid electrolyte.  They can even be mounted upside down.

Michael
'83 300SD, I'm back!  It's the son's new car (12/2020)
1976 450SEL, 116.033  Sold it to buy a '97 Crown Vic.  Made sense at the time.
1971 250C, 114.023
1976 280C
1970 250/8

nathan

im with Mforcer,
the optima is the best battery! have it in my gwagen and takes all sorts of abuse from heavy demand.  much smaller yet no problems with power delivery and dry cells allow mounting however the hell you want!

Bill, wrt to that pic - i know its often been quoted as an 'AMG intake'...im always a bit cynical about these 'AMG' things as once someone hints its AMG, that label seems to stick no matter how flimsy the evidence.  i cant imagine that AMG would go to effort to get better air intake and all they could come up with is this piddly little additional snorkel? 

i think your boot mounted battery sounds like a much better idea as you could then stick a much bigger intake into this non crowded area.

keep us posted
nathan
1979 116 6.9 #6436
2018 213 e63
2011 212 e63
2011 463 g55
2007 211 e500 wagen
1995 124 e320 cabriolet
1983 460 300gd
1981 123 280te

peterq

Go to the marine shop in Leederville, they have plastic battery boxes for boats at reasonable prices, complete with a lid. Should protect you from leaking acid - I'm guessing that having the floor of your boat eaten away by a leaky battery could be serious.
Since 6.9s are often on the edge of heat induced voltage drop and subsequent starting problems, I think a smaller battery could be a wrong move. Until a relay was introduced into the circuit I spent many a half hour in Boyanup (where we pulled in for a drink on our way south) waiting for things to cool so the starter would spin.

WGB

Thanks Guys - this is becoming bigger than Ben Hur.

At this stage I will make haste slowly.

Bill