View Full Version : cheap performance mods
cherrykee
20-10-2002, 05:04 AM
hi folks
has anyone experimented with different spark plugs
or filters(ie K&N) to achieve small quick performance gains? also the big thing in the US seems to be putting vents in the hood, anyone tried this in sydney? one guy i know has here in melbourne. and if so which vents from which car
Kramer
20-10-2002, 05:18 AM
Welcome to our little corner of the web, cherrykee
You're in luck with wanting info on the Cherokee, we have our own resident performance-come-fuel economy fanatic (sorry gojeep!) here, go to his website and eat your heart out. Very knowledgable guy.
smile.gif www.go.jeep-xj.info (http://www.go.jeep-xj.info)
Kramer.
[ 20 October 2002, 05:21 PM: Message edited by: Kramer ]
Gojeep
20-10-2002, 06:48 AM
Gee thanks Krammer but I am not that good! :cool:
Anyway to the question on the hood vents. Some of the first XJ's came here with the vents already on as was a cheap way for Jeep to cope with our high temps. They used the ones from the Grand Cherokee when they first put in the V8 in the States to cope with the higher temps. I tried to get some from Jeep and even though they are listed they are not avaliable here and the prices were shocking.
Placement is very important as you must put them near the front in the low pressure area of the bonnet where the air flow is bounced off the front creating this before it pushed down hard at the base of the screen. It will then suck out air from under the bonnet causing more air to be drawn through the radiator to equalized the pressure difference created.
I am fitting some soon but may have run out of time this year but after much research have decided the best vents to use is off a Datson 260Z after 1976 when they were fitted. New they work out at $70 each that I was quoted and had to come from Japan but was offered some for $45 a pair secondhand but they turned out to have broken studs.
Let me know if you want more info on the subject. ;)
Hi,
Marcus, do those guys still exist who used to press the "sharks gills" in Torana and Holden front guards?
Seemed there was a big after-market operation doing guards on an exchange basis.
If they still exist, might be an easy way to get hood vents, just get them to press some flutes in.
Gojeep
21-10-2002, 04:11 AM
Too late. :eek: I already have ordered the vents with the left in stock in Melbounre and the right being un-packed from the warf at the moment. :rolleyes:
You know what I am like about waiting around. tongue.gif
I had already looked into to your sugestion some time ago but these vents come with studs so you only need to cut the hole and bolt them down!
cherrykee
21-10-2002, 05:17 AM
thanks alot guys for the advice
i will look into it, the datsun vents
do seem to be the go, the guy in melbourne jeep club, bought some louvered vents from automart or one of the other accesory outfits, i will check those out too.
Jeepdownunder
21-10-2002, 12:20 PM
Vents in bonnets, shark gills, Toranas & Datsuns :rolleyes: You can get some fluffy dice for the rear view as well.
http://fototime.com/{8565FDC1-5AD4-40BE-B7A8-7B90A5F4CE60}/picture.JPG
[ 22 October 2002, 12:29 AM: Message edited by: Jeepdownunder ]
Hi,
Forget the dice, They only came on old valiants, guess it stays in the chrysler family graemlins/headspin.gif
Now how do I make a quick conversion from snorkel to GTHO falcon shaker graemlins/moon.gif
On a serious note... anyone had one of those tripple or quad core radiators made up for your XJ? How much was it, who made it? I am thinking of big radiator with only electric fans. Anyone done this?
AussieCJ7
22-10-2002, 04:05 AM
what about the bonnet vents for a EB GT falcon ??
there are heaps of body kit manufactures making them I think they are about $60 a pair but it has been a few years since I priced them
I have seen a few taxi's with them for the same reason
[ 22 October 2002, 04:06 PM: Message edited by: AussieCJ7 ]
Gojeep
22-10-2002, 06:09 AM
Originally posted by AussieCJ7:
what about the bonnet vents for a EB GT falcon ??
there are heaps of body kit manufactures making them I think they are about $60 a pair but it has been a few years since I priced them
I have seen a few taxi's with them for the same reason<font size="2" face="Verdana, Helvetica, sans-serif">They are pretty small and are oval in shape so dont suit a Jeep. The Ford Seirra ones are better but are for a bonnet with some curve in it.
I had a set from the Auto parts store but they were pretty crap as only plastic and very weak. Sold them to someone in the States. :rolleyes:
Gojeep
22-10-2002, 06:11 AM
Here are the ZJ ones I was talking about.
http://www.nagca.com/grandtech/hoodvents.htm
Jimmyb
22-10-2002, 09:15 PM
after fitting my discos, thought i would sticky beak at the air box, jezz the ole paper filter was a mess, so im now thinking of poping a K&N in there to allow me to clean and service it after each dusty trip so i dont have to wait between services.
who here is interested in getting a K&N, we might be able to do a bulk buy with someone online? i found one site with filter and cleaning kit and oil for approx $55US with free shipping.
Gojeep
24-10-2002, 05:22 AM
I would never use a drop in K&N as they reduce the surface area by having less folds but still let more air through. :rolleyes: The problem with this is that they let more dust through with it as the only why to get more air flow is by increasing the surface area if you still want to filter down to the same micron level.
The form filters have the same problem as you have to get the oil saturation just right becuse to little you suck dust and too much the fuel economy dives. Believe me I have tried. :mad:
There are many tests on the web showing how bad the K&N are so dont just take my word for it.
Here is one that was posted on JU;
K&N re-tested...
Are "Performance" Air Filters a Good Idea?
The following information was taken from a posting by Jim Conforti (AKA the Land Shark). Jim is a well known tuner in BMW circles. His web site is the Bonneville Motor Werks. The testing was done on a BMW air filter but the concepts should apply to all manufacturers.
Comparing Stock to Performance Air Filters
First, a "prologue". This was a scientific test, not one done by filter manufacturer X to show that their filters are better than manufacturer Y. The test results are pretty irrefutable as the test lab tests and designs filters where "screw ups" are absolutely NOT allowable (I can't say any more for security. Think "Glow in the Dark").
OK, with that in mind, onward.
A scientific test was done on TEST filters where air was loaded with ACCTD (some standardized "test dust" called AC Coarse Test Dust) and sucked through the TEST filter then through an analysis membrane.
From the Quantity of dust injected and the amount that gets thru the TEST filter and is then captured on the analysis membrane we can calculate the efficiency of the TEST filter in Question.
First, the filters:
BMW Stock Filter, Eff. Area of Media: 8.4 sq ft.
K&N Replacement, Eff. Area of Media: 1.6 sq ft.
The filters are the SAME size. They both fit in the STOCK BMW M3 airbox. The difference is that the STOCK filter has 65 pleats 1.5" deep and the K&N only 29 pleats each 0.75" deep.
Now, remember this ratio: " 5.25:1". It's the ratio of the AREA of STOCK to K&N. It's very important and will come into play later.
The STOCK filter efficiency started at 93.4% at 0 loading and increased to 99.2% efficiency as the loading increased to a max tested of 38.8 gm/sq ft of dust.
The K&N filter efficiency started at 85.2% at 0 loading and increased to 98.1% at the max tested loading of 41.38 gm/sq ft.
Now, I hear you. "Jim, that's only a FEW PERCENT". But is it?
Let's look. If we had 100 grams of dust on a new BMW filter we would let thru a total of 6.6 grams of dust in. If we used the new K&N filter we get 14.8 grams of dust. Thats 224% (TWO HUNDRED TWENTY FOUR PERCENT!!) more dust ingested initially, stock vs. "free flow" and this ratio is pretty much held. Somewhere between 200-300% more dirt gets "ingested" anywhere across loading equivalence.
The more INTERESTING thing is when you look at what happens to the DP or Differential Pressure at a constant airflow as you dirty both filters equally with time.
The test used a rate of 75gr of dust per 20 min. Here's where the AREA difference comes MAJORLY into play. See, even though the BMW filter flows a bit less at the SAME loading, it also LOADS UP 5.25 times SLOWER due to it's LARGER effective area. So what happens is that the K&N initially flows better, but as the dirt continues coming in, the K&N eventually flows WORSE while still letting MORE dirt in.
Now, does any of this additional dirt cause problems? I dunno. I suppose we could have a few people do some independent oil analyses on different motors using both K&Ns and Stock filters. Get enough of them, and you'd have a good statistical basis. For me though, it's simple: More DIRT = BAD.
The additional short-term airflow might make sense on a track car. IMHO, it doesn't for the street.
--
Just thought I'd liven things up abit
__________________
OzJeeper
31-10-2002, 08:57 AM
A comment has stuck in my mind from a conversation I had with a clubie who went into the Desert/Centre.
His quote was "Yeah, we took a spare air filter with us and it was paper. From last trip we learned this was the best option. It was fun watching all those other guys washing their air filters out - each and every night. Smelled the whole place up though. Never had a problem all trip and never got my hands dirty once."
Says volumes I think.... :D
OzJeeper
31-10-2002, 08:59 AM
I forgot to mention,
There is no such animal as a cheap performance mod.
(Puts on flame proof suit and....) graemlins/crying.gif
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