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wheel607 Samba Member
Joined: May 30, 2004 Posts: 1845
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Posted: Sun Aug 23, 2020 8:33 am Post subject: Re: Ram-air Cooling Ducts |
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Would a piece of Filtron foam help to keep the road crap out of the engine compartment or would this defeat the ram air duct? I like your process by the way. Carry on with more experiments in this area....have always thought the same for 50 plus years. I was excited to see Renault and then Ferrari work to this end! |
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Floating VW Samba Member
Joined: April 28, 2015 Posts: 1596 Location: The South Zone
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Posted: Sun Aug 23, 2020 9:29 am Post subject: Re: Ram-air Cooling Ducts |
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Hey, thanks everybody! Every time I start one of these threads, I wonder if it will finally be the one where everybody figures out I really have no idea what I'm doing. But I have my fun, and that's what counts!
I'll try to answer the questions all in one go here:
Chickensoup wrote: |
. . . Do you have a cylinder head temp gauge?
Do you think it will disrupt the air flow coming from the fan and underneath the engine? . . . |
I actually have two CHT gauges, one for each head. But I don't have the probes in the "standard" location under the spark plug, so I don't bother posting my CHT's. Also, the gauges are disconnected at the moment (the night lighting doesn't match the rest of my gauges, so I have it out to correct that).
The airflow under the engine shouldn't be affected at all. I'm only re-directing the air that would normally flow over and around the rear fender, not the air under the car.
bedlamite wrote: |
So when are you going into full production? |
Hah! Not for a long time, and only if someone were willing to pay me a ridiculous amount of coin. I absolutely loath doing fiberglass work! But seriously, I'm only in the prototype stage at the moment, so I have a lot of testing to do before I would even consider it.
Rome wrote: |
. . . For rainwater- consider drilling an approx. 1/4" hole at the rear lower section of the expansion chamber.
As to a grill for the air inlet. . . |
I actually had that very same idea, but I wanted to see if rain water would be a problem before I started drilling holes. Good ideas for a grill- I'm also on the fence about that. I prefer the esthetic of the completely open intake, but if a grill proves necessary, I'll have to figure something out.
sled wrote: |
. . . so, what I would like to see is an engine bay air pressure test. . . |
Me too! The whole time I was making the ducts, in the back of my head I was wondering how fast I would have to drive to ram enough air down them to over-pressurize the engine compartment. I might try the string test on the louvers and see if there's any change, with ram air vs. without ram air.
Glenn wrote: |
Nice but it shouldn't bee needed.
Even a large engine can be cooled enough in a stock Beetle engine compartment.
And too cool is not good also. |
True, and true. The low pressure zone at the rear of the car doesn't seem to become a problem for engine cooling until about 70 mph, or so. Most people rarely get over 60 mph during normal highway driving. But there are a few places where sustained higher speeds are legally possible, and that's what I designed these ducts for. That, and a possible reduction in aerodynamic drag.
Too cold is actually one of the biggest problem I have with my machine. Especially in the winter months. But I can't stop coming up with new ways to make it run cooler. It's like a sick, twisted obsession or something! I did keep the sheet metal from the intake cut-outs, which I intend to use for a pair of inserts to block off the air ducts when the weather turns cold.
DerrickfromNC1 wrote: |
Nice!...... What kind of air cleaners do you have on your webers? . . . |
Regular old K&N. They're not the best, but they seem to be doing a proper job, so I didn't bother to upgrade them. At least, I've never had a plugged jet, nor do I ever notice any dirt or debris inside the carburetors.
Oh, the Darla twins are actually Dellorto DRLA's, not Weber's. But "Dellorto windows" just doesn't sound as good.
Alstrup wrote: |
It has been done many times on high power German look cars. But that doesnt change the fact that it works well, and you have put some effort into it. . . .
. . . But then you have an excuse for making a version 2 |
Thanks, I actually love it when this happens! Some people might get upset when they find out their "original" ideas have already been done before, but I just see it as confirmation that my idea is a good one. It's also confirmation that I'm not a complete nut job, or at least not the only complete nut job!
I'll definitely keep an eye on the amount of debris that ends up in the engine compartment. It's good to know that half the size is sufficient; I was originally planning to install a series of baffles inside the ducts to filter out the junk, but decided against it in the interests of not reducing the air flow. It's good to know that baffles are back on the table for version II, if needed.
High power, German look cars, indeed! My machine is going to get a kick out of that when I tell it!
Rome wrote: |
67rustavenger, I understand your opinion and think it's valid- my response "diluted" the OP's excellent work. If I could still edit my last response, I'd delete it. But that option is no longer there, so if the moderator wants to delete my last response, I'd be OK with that. |
Don't sweat it, man! I think it's good to have as many different solutions as possible. I've also seen the one you were talking about; it's not a bad idea- probably a lot easier to implement than what I did.
If anybody knows of a better way to skin the cat, don't keep it a secret! _________________ "It's time you started treating people as individuals, rather than mathematically predictable members of an aggregate set, regardless of how well that works." |
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Floating VW Samba Member
Joined: April 28, 2015 Posts: 1596 Location: The South Zone
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Posted: Sun Aug 23, 2020 9:32 am Post subject: Re: Ram-air Cooling Ducts |
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wheel607 wrote: |
Would a piece of Filtron foam help to keep the road crap out of the engine compartment or would this defeat the ram air duct? I like your process by the way. Carry on with more experiments in this area....have always thought the same for 50 plus years. I was excited to see Renault and then Ferrari work to this end! |
I also wondered the same thing. It's definitely another option, if I need it. _________________ "It's time you started treating people as individuals, rather than mathematically predictable members of an aggregate set, regardless of how well that works." |
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67rustavenger Samba Member
Joined: February 24, 2015 Posts: 9665 Location: Oregon
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Posted: Sun Aug 23, 2020 10:25 am Post subject: Re: Ram-air Cooling Ducts |
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I retract my statement from page 1.
The OP seems to be ok with discussing other ideas for engine compartment "Ram Air" cooling.
Sorry. I was a bit tired after working 10hrs. yesterday.
67rustavenger wrote: |
This discussion should be held in another thread.
The OP has presented his design and fabrication, as his idea for better cooling and air to the carbs.
Personally, I like what the OP has accomplished. It is well documented and he deserves to have this thread uncluttered by other ideas that have been tried and may have worked to a degree. But these other ideas are not what the OP had in mind. For his build.
Nice work OP!
Rome wrote: |
Pruneman99 wrote: |
But I was thinking more of grabbing the air from the bottom or front of the car and directing through the package tray/firewall straight into the fan. Water/debris always felt like a problem and I never could imagine a way to solve that mentally. But I'm not an engineer, or very motivated lol.
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John P from the Cal-Look Forum did this on his '67 Beetle to help cool his 48 IDA-powered 2007 cc engine. Maybe there's an archived article in that site. What he did was to make an inlet at the engine front breastplate on the right side, close to where the fan air inlet is. He led a hose forwards to the right side of the transmission, low down so that it was about even with the level of the pan, and attached a flat rectangular funnel at the front of the hose. IIRC he used the same type of hose as for the fresh-air outlets of the fan shroud. The funnel was somehow suspended or maybe even held to the right side of the transmission, and possible also from the body using that "J" channel along the bottom of the rear quarter panel. I don't remember if the rear of the hose ended right at the breastplate, or if it extended rearwards through it and aimed upwards toward the cooling fan inlet.
I saw his car at a VW meet in Harwinton, CT back in June 2014 at which point he had a period-look single-port engine with dual single-throat carbs. I did not look under the car to view the inlet setup. But it was a well thought-out modification per the photos in his article. |
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_________________ I have learned over the years.
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Sun Aug 23, 2020 10:27 am Post subject: Re: Ram-air Cooling Ducts |
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Floating VW wrote: |
wheel607 wrote: |
Would a piece of Filtron foam help to keep the road crap out of the engine compartment or would this defeat the ram air duct? I like your process by the way. Carry on with more experiments in this area....have always thought the same for 50 plus years. I was excited to see Renault and then Ferrari work to this end! |
I also wondered the same thing. It's definitely another option, if I need it. |
Very nice work! I use the foam for molding of large pieces as well.
I use this....as its very predictable and can be altered in its expansion rate.
https://www.smooth-on.com/product-line/foam-it/
As for keeping debris out of the engine compartment...I would stay away from filters. I think you are correct that it will GREATLY reduce the ram air effect.
A less restrictive (maybe) idea...is to use an added plate or flow shaper inside that makes the air go through a rapid directional change...like 90* or greater before going straight on its original path.
This creates a centrifugal action that allows larger, heavier debris and dust to be thrown out of the airflow...and not be able to make teh turn. This is actually the operative function of oil bath air cleaners. They have one major 90* and then a quick 90* again right over the oil pool where teh vast majority of large particles are lost.....then many micro twists, turns and directional changes through the fiber in the filter where they centrifugally drop smaller grit and large oil droplets.
I think this same methodology has and can be done for brake cooling vents as well.
Personally ...I dont really see other ideas of how this has or can be done.....being thrown into your thread as contaminating your thread. Its till on topic....and this thread can be a fantastic platform of how to even think about starting this mod and why....and still showcase your work and effort!
Ray |
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Floating VW Samba Member
Joined: April 28, 2015 Posts: 1596 Location: The South Zone
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Posted: Sun Aug 23, 2020 11:07 am Post subject: Re: Ram-air Cooling Ducts |
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67rustavenger wrote: |
I retract my statement from page 1.
The OP seems to be ok with discussing other ideas for engine compartment "Ram Air" cooling.
Sorry. I was a bit tired after working 10hrs. yesterday. |
No worries, man. You were just trying to look out for me, and I appreciate that. _________________ "It's time you started treating people as individuals, rather than mathematically predictable members of an aggregate set, regardless of how well that works." |
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vwracerdave Samba Member
Joined: November 11, 2004 Posts: 15280 Location: Deep in the 405
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Posted: Sun Aug 23, 2020 11:13 am Post subject: Re: Ram-air Cooling Ducts |
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One negative I see is you might be limiting your tire size with the extra ducting inside the wheel well.
I know they may not look as cool but the side scoops that go behind the rear qtr windows will effectively do the same thing.
https://www.thesamba.com/vw/classifieds/detail.php?id=1480347
_________________ 2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK
Featured in Dec. 2001 HOT VW's Magazine page 63
Watch my racing video's http://www.youtube.com/user/okvwracer/videos |
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Floating VW Samba Member
Joined: April 28, 2015 Posts: 1596 Location: The South Zone
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Posted: Sun Aug 23, 2020 11:28 am Post subject: Re: Ram-air Cooling Ducts |
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raygreenwood wrote: |
Very nice work! I use the foam for molding of large pieces as well.
I use this....as its very predictable and can be altered in its expansion rate.
https://www.smooth-on.com/product-line/foam-it/
As for keeping debris out of the engine compartment . . .
Ray |
Thanks, Ray.
Variable expansion foam, nice! That's the reason I said stay away from high-expansion spray foam, the cells are all over the place in size, and it doesn't cure right. It's not predictable at all.
A series of baffles to force the air into a bunch of 90 degree turns is exactly what I had in mind, if debris becomes too much of a problem. I've already got this exact set-up on my crankcase ventilation system. We'll see how it goes.
vwracerdave wrote: |
One negative I see is you might be limiting your tire size with the extra ducting inside the wheel well.
I know they may not look as cool. . . |
Yep, one of the reasons I think going into production would be more difficult than it's worth is tire size. It could be done, but you would almost need a tailor-made duct for every tire on the market. How much the suspension is lowered also comes into play.
I've seen those scoops before, they look pretty cool to me. I thought about going that route, as well, but I wonder if they don't introduce some aerodynamic drag. _________________ "It's time you started treating people as individuals, rather than mathematically predictable members of an aggregate set, regardless of how well that works." |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Sun Aug 23, 2020 7:04 pm Post subject: Re: Ram-air Cooling Ducts |
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All cars, vans and pickup trucks have this "design flaw" that creates a vacuum behind them. Some a bit worse than others of course. It is true though that the VW with the rear engine could be having negative cooling issues from it. VW's engineers may have anticipated that and oversized the fan some, I don't know but I cannot see a down side to this. Road dust comes in the stock vents already.
Anyway it is a very interesting concept and yes please run some before and after engine compartment pressure tests please! |
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nextgen Samba Member
Joined: August 19, 2004 Posts: 6008 Location: CONGERS, N.Y.
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Posted: Sun Aug 23, 2020 7:53 pm Post subject: Re: Ram-air Cooling Ducts |
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Before I knew if using a T-1 fanhousing to cool a 2.0 T-4 engine. as a precaution I bough $500 worth of Earl's heavy duty oil lines, oil cooler and Sandwich adapter with thermo switch that fit between oil filter and case.
Problem was I did not want to put the cooler under the bug after seeing the effects of what salt, and gravel did to coolers.
I to notices the salt spray just above the running boards to the rear fenders.
I mounted the cooler , side to the body of the bug on the running board just short of the fender and made an aluminium Intake cover which was not wider then the fender. The cooler was protected. The hoses ran thru 2 holes I drilled in the running board.
Did not need it the T-4 was having problems reaching a running temp of 170f. Plugged the ruining board holes.
I sold it all at a swap meet in Woodstock NY for $50.
You are on the right track with your design and location. Artists have different mediums the use, that form in this case is yours. _________________ email: [email protected]
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k@rlos Samba Member
Joined: October 04, 2012 Posts: 485 Location: Suffolk, England
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Posted: Sun Aug 23, 2020 11:03 pm Post subject: Re: Ram-air Cooling Ducts |
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Not my thing but awesome work!!! |
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Floating VW Samba Member
Joined: April 28, 2015 Posts: 1596 Location: The South Zone
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Posted: Mon Aug 24, 2020 7:25 am Post subject: Re: Ram-air Cooling Ducts |
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Thanks, man. _________________ "It's time you started treating people as individuals, rather than mathematically predictable members of an aggregate set, regardless of how well that works." |
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Floating VW Samba Member
Joined: April 28, 2015 Posts: 1596 Location: The South Zone
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Posted: Mon Sep 07, 2020 10:40 am Post subject: Re: Ram-air Cooling Ducts |
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So, I finished the passenger side a few days ago and gave the whole system a shake-down. Here is my preliminary report:
The first test I did was for tire clearance, which was pretty straight forward. I took it over increasingly larger bumps in the road, and everything was thumbs up- until I hit the absolute biggest bump in the absolute worst road that I know of in the tri-county area. With the suspension was fully loaded (meaning, the bump stops touching the shock towers), the cooling ducts were designed to clear the tires with about an eighth of an inch to spare. It wasn't enough:
Both sides kissed the ducts, not hard, but hard enough to require a little modification. So I made a little indentation to give it some extra clearance. In retrospect, this turned out to be kind of a fortunate design flaw, as the modification adds a considerable amount of cross-sectional strength (not that it really needed it), and makes it look cooler!
With that problem out of the way, I took it for a run down the highway, and noticed some very interesting behavior.
The first thing I noticed was an increase in exhaust gas temperatures. With the ram-air intakes open, at about 60 mph and 3100 rpm (aka light cruise), EGT's were almost 100°F higher than normal.
The second thing I noticed was a subtle power increase and an odd "runaway acceleration" effect that seemed to start at about 50 mph, and got more noticeable as speed increased. At 60 mph, I found myself having to constantly lift off the throttle to prevent the car from slowly continuing to accelerate, and if I wasn't paying attention, I would soon find myself doing 65 or 70 mph and have to lift again. At first, I thought it was just my imagination, or maybe the result of a strong tail-wind or something, but after repeated tests, it was definitely something related to the air ducts (and I think I know what, but more on that, later).
The third thing I noticed was the difference in engine bay temps, with ram-air vs without ram-air. With the ram-air intakes covered, I took it for a spin down the highway at 60-65 mph, followed by an equal drive with the intakes open for business; ambient temps were about 82°F for both runs. Measuring certain areas on the engine, this is what I got:
Notice the eight-degree drop in oil temps! This exact same temperature drop was also seen by the oil temp gauge, in case you were wondering.
Another interesting thing I observed was that under normal conditions, the left and right-side intake manifolds don't operate at the same temperatures (129°F vs 119°F) and neither do the carburetors (115°F vs 110°F), probably due to the closer proximity of the cooling fan. As you can see, this anomaly was largely corrected by the cooling ducts.
These cooler carburetor and intake manifold temps are what I attribute the subtle power increase and runaway acceleration to, as well as the increase in EGT's. I haven't measured it yet, but I seriously doubt the air ducts are over-pressurizing the engine bay at highway speeds, so I don't believe there is any type of forced induction going on. Most likely, the cooler (and more evenly cooled) intakes are allowing a denser and more energetic air/fuel charge to enter the combustion chamber, especially at higher speeds. After a bit of testing, I found that reducing the air-correction jets in the Darla twins from 180 to 170 brought the EGT's down by about 50-60°F, and seemed to lessen the runaway acceleration a bit, so I might try a set of 160's and/or play with the rest of the jetting a little, or I might just leave it all alone for now, we'll see how it goes.
But for sure, I am enjoying the subtle increase in power. Something I noticed a long time ago was that every ACVW engine I'd ever owned seemed to make the most power when the ambient air was cool and dense, and the engine was just barely reaching safe operating temps, and the intake runners and cylinder heads were just warm enough to prevent the fuel from condensing out of the intake charge, but not yet hot enough to thin it out as it enters the chamber. I started a little topic on this a few years ago, if you want more on that: https://www.thesamba.com/vw/forum/viewtopic.php?t=643542&highlight=
Well, I'm happy to report that my machine is like that all the time now, even after a long run down the highway on a hot summer day! And as a bonus, the strong gasoline smell I used to get in the garage from all the heat soak in the Darla twins after shutdown is almost gone, now that they are being kept nice and cool by the air ducts.
OK, that's all I have for now. I'll post up my results after I get some more testing done. _________________ "It's time you started treating people as individuals, rather than mathematically predictable members of an aggregate set, regardless of how well that works." |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Mon Sep 07, 2020 11:00 am Post subject: Re: Ram-air Cooling Ducts |
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Thanks for the update and test results!
To my knowledge all engines benefit from a cooler, denser intake air charge not just VWs.
Now it will be interesting to see how it all works in the rain. What gets wet and what doesn't like it if it does. |
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Lingwendil Samba Member
Joined: February 25, 2009 Posts: 3987 Location: Antioch, California, a block from the hood
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Pruneman99 Samba Member
Joined: February 22, 2012 Posts: 5013 Location: Oceanside
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Posted: Mon Sep 07, 2020 11:50 am Post subject: Re: Ram-air Cooling Ducts |
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Wow! Now that is some testing! Great results.
If rain becomes an issue, maybe there is a way to put a valve you can close? Or if it's cold and you didn't want the extra cooling?
Your parts look sweet btw |
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mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
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Posted: Mon Sep 07, 2020 12:34 pm Post subject: Re: Ram-air Cooling Ducts |
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nice work,I usulay dont let the gel coat set fully before adding the glass., like allsury said rocks&dibris...you may in the future add a angled screen & a trap door on the bottom for removing any debris. you going to add one to the other side??you could feed the crabs with them too( I was planing on a siumular duck on mine to the carbs, but never got a round tuit. |
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spencerfvee Samba Member
Joined: August 19, 2004 Posts: 3071
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Posted: Mon Sep 07, 2020 1:22 pm Post subject: Re: Ram-air Cooling Ducts |
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holy shit thats so cool .i am going to do that to my ralley bug . you do super nice work . i to am going to cut for webers .i am glade you posted your build on samba spencerfvee |
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vwracerdave Samba Member
Joined: November 11, 2004 Posts: 15280 Location: Deep in the 405
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Posted: Mon Sep 07, 2020 1:47 pm Post subject: Re: Ram-air Cooling Ducts |
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You guys (spenccerfvee & wheel607) need to stop hitting the quote button to respond when there are 20 pics in a post. Scrolling thru a post that has been quoted 4-5 times like this one and having all the pics repeated is pointless and extremely annoying. Simply type in the members name and make your comment. _________________ 2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK
Featured in Dec. 2001 HOT VW's Magazine page 63
Watch my racing video's http://www.youtube.com/user/okvwracer/videos |
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Chickensoup Samba Member
Joined: January 06, 2018 Posts: 5368 Location: Good Hope, GA
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Posted: Mon Sep 07, 2020 8:11 pm Post subject: Re: Ram-air Cooling Ducts |
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vwracerdave wrote: |
You guys (spenccerfvee & wheel607) need to stop hitting the quote button to respond when there are 20 pics in a post. Scrolling thru a post that has been quoted 4-5 times like this one and having all the pics repeated is pointless and extremely annoying. Simply type in the members name and make your comment. |
thank you. i didnt think it was gonna end lol _________________ -'85 c10 5.3 LS, 222 cam, long tubes, x pipe, 3 inch spin tech's
-'05 B5.5 TDI Wagon 17in sport rims ;EGR + BSM + ASV Delete, Stage-2 Tune, straight pipe
'65 Tourist Delivery Build
'66 RIP
'69 RIP
Hosea 4:6 "My people are destroyed for lack of knowledge" |
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