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Post by pushnfords on Jun 28, 2010 17:37:36 GMT -5
When I was talking to VW Paradise about a mild performance engine the guy told me it was basically pointless unless I upgraded the gears in the trans axle. He said if I kept the engine under 3K rpm for longevity that I'd be running around 55mph depending on tire size. Is that right? I'd hoped that the car would be capable of cruising 70-80 mph on interstate.
How fast will your car go at what RPM and with what tires?
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Eric A
Full Member
It's an obsession not an investment!
Posts: 223
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Post by Eric A on Jun 28, 2010 17:43:55 GMT -5
This is a Jeff Troy question when it comes to longevity. I have a stock IRS an a 1641 that I drove on the interstate for years without issue I don't remember the rpm but it was not overly high as I recall. I drove between 70 and 75.
Eric A
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Post by centralvalleygter on Jun 28, 2010 18:03:51 GMT -5
Stock VW's actually develop their best torque between 3200-3900 rpm. Type 1 1600cc engined busses (changed to different engine type in '72) will run years @ about 65mph which with their lower gearing works out to be 3800rpm or so (if kept cool).
My 1641cc dual Kadron runs at about 3300rpm at 70mph. I checked the speed with my GPS. I am not sure whether the IRS trans has stock gearing or not, but I'm running the tallest profile 14" tires I could get (P215/75R14) on the rear which have a diameter of 25.875". I've had it up to 90mph (about 4400rpm) with room to keep going. I had the engine in my BAHA before the Bradley. The engine is 25+ years old with over 100,000 miles without a rebuild and still going strong.
The most important things about longevity with ACVW engines is oil change and valve check/adjustments every 2500 miles or so. That and making sure the oil stays cool.
Sincerely,
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Post by centralvalleygter on Jun 29, 2010 10:37:40 GMT -5
Correction concerning the bus info I gave above. The info I gave was according the bus' own speedo. After writing the post I was making a trip in my bus and remembered that it's speedometer is off by 6-7 mph at 60+mph according to my GPS (which I understand was typical of all american vw busses at the time because they used 14" wheels here whereas 15" wheels were used in Europe & Latin America). So that means at a true 65mph the engine is spinning at more like 4200rpm. To run this rpm for an extended amount of time (hours) on a stock ACVW engine might be pushing things a bit in terms of longivity.
Regards,
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Post by Jeff Troy on Jun 29, 2010 15:09:54 GMT -5
I use the stock VW Freeway Flyer transmission, which has a higher fourth gear.
My engine is a mild 1641, fly-cut heads, dual Kadrons, Berg dual quiet pack exhaust, Berg rocker shafts, Pertronix ignition, coil and wires, and a bottom-mount oil sump. Stock rods, crank, cam, rocker arms and lifters.
Turnpike at 3000 RPM is 65 MPH.
3200 is 70.
3500 is 75.
My car has more than 630,000 miles behind it, and the greatest contributor to longevity is not the equipment; it's the way the car is driven.
Let the oil circulate. Let the engine idle for two-or-more minutes after the first start each day before driving.
Don't drive like a drunken teenager. No jackrabbit starts, no peel-outs.
Shift at approximately 3,000 RPM. You don't really need the tach; listen to the engine.
Don't bog the engine down in a higher gear than you need. Downshift when you should.
Treat your car like a friend. The VW sedan was designed as the world's least expensive family transportation. It isn't a race car. If you drive it like a race car, it will f*ck you where you breathe.
My mileage is high, but understand that almost all my miles are highway miles. Highway driving is very easy on brakes, shocks, suspension and transmissions, and at 3,000 RPM, the VW is like to last a very long time. I did only one rebuild on my engine, and that was at 340K. The engine was still running fine when I tore it down.
Warmest...
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Post by vallyr on Jun 29, 2010 18:18:12 GMT -5
i have a single port 1600 and before it was a bradley id do 70-80 on the freeway comfortably, though it didnt like to go 80+ unless it was tuned right. Going over the pass through the cascade mtns it would want to cruise at 90-dont ask me why, i think its some crazy german engineering that only kicks in when in high alpine regions.
Course the original PreWWII motor was far less cc's and was designed to do 62 on the autobahn
Then again the previous owner of my vw did some modifications for drag racing. Not all of them have even been identified yet. For example he put in a racing clutch , which was already toasted that I replaced with a standard clutch. Breather boxes on the valve covers and some other stuff I have yet to identify.
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Post by vallyr on Jun 29, 2010 18:22:33 GMT -5
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Post by don29163 on Jun 29, 2010 19:19:37 GMT -5
That was fun !!
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geddes66
Junior Member
Now I am an instructor at the RTS-M, Camp Roberts CA. Teaching new Army mechanics.
Posts: 87
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Post by geddes66 on Jul 1, 2010 0:22:52 GMT -5
My brad cruises at about 3000 at 70 MPH. I have a 2007 CC engine that uses a type 3 cooling system. It is both "bored" and stroked with 90.5 mm cylinders and a 78mm crank. It has 36mm Delorto carbs, a mild cam and a DIS/X ignition system. The cruise RPM is standard from the trans but I am running larger tires in the rear.
I have had it to about 105 MPH when passing a semi-truck once. I shifted to 3rd and floored it for about 10 seconds and just held to the floor for an extra 15 seconds after getting around him.
There was ALOT left but these things are NOT meant to actually GO fast, just look like they do. The front end which only weighs 600 pounds, even with the battery mounted in front of the torsion bars, was getting light at that speed.
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Post by mrbigh on Jul 1, 2010 9:44:48 GMT -5
Can we call your Brad a GEDDES-S66 rocket?
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geddes66
Junior Member
Now I am an instructor at the RTS-M, Camp Roberts CA. Teaching new Army mechanics.
Posts: 87
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Post by geddes66 on Jul 7, 2010 0:52:33 GMT -5
Maybe not a rocket but it looks like a turbine. Attachments:
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Post by mrbigh on Jul 7, 2010 9:35:34 GMT -5
......and you should always keep a guard dog near by..  |
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Post by Gary Hammond on Jul 7, 2010 11:44:06 GMT -5
Hi Horacio,  ......and you should always keep a guard dog near by.. "Guard Dog"   ...................I knew Chris was in the Guard, but I didn't know his dog was as well!!   ;D (Sorry.....just couldn't resist.)  Gary Hammond,  |
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Post by Gary Hammond on Jul 7, 2010 12:08:46 GMT -5
Hi Derek, ............He said if I kept the engine under 3K rpm for longevity that I'd be running around 55mph depending on tire size. Is that right? I'd hoped that the car would be capable of cruising 70-80 mph on interstate. How fast will your car go at what RPM and with what tires? Sorry for the late answer, but here goes. ............1967 swing axle with .89 4th gear and 4.125 final drive ratio. Modified 1678cc engine, P235/60 R15 rear tires (796 rev/mile), and P215/60 R15 front tires (827 rev/mile). Calibrated electronic tach and speedo. It goes 20.53 MPH for each 1000 engine RPM in 4th gear. 72 MPH is 3507 RPM. Top speed ............... , don't really know. I chicken out at anything over 95MPH! Engine is good for 6000 RPM in all the lower gears though. Gary Hammond, |
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Post by pushnfords on Jul 12, 2010 20:15:42 GMT -5
Thanks everyone! The owner is planning on using this as his primary driver. The engine building is saying 3000-3500 cruising rpm is no problem...but depending on rear tire choice (have 14" wheels now) that may not get us to or above 70mph. I'm wanting to just put it together and see how close we get but waiting to hear back on that.
In the meantime...are there aftermarket gears available to increase the top end?
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Post by centralvalleygter on Jul 12, 2010 23:51:29 GMT -5
Yes, the phrase "freeway flyer" is used in the VW tranny industry to indicate a higher gearing. Different tranny builder's have their own various ways of getting the higher gear ratio, most (but not all) just affect 4th gear. See Jeff Troys post above.
Regards,
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Post by pushnfords on Jul 13, 2010 21:26:21 GMT -5
Yes, the phrase "freeway flyer" is used in the VW tranny industry to indicate a higher gearing. Different tranny builder's have their own various ways of getting the higher gear ratio, most (but not all) just affect 4th gear. See Jeff Troys post above. Regards, I like Jeff's combo...very close to the one I'm working on. And if I can get those speeds at those rpm's the owner should be happy. Is the "Freeway Flyer" trans one that was used in certain models and/or years or is it an aftermarket variation? From what I could tell looking around last night the R&P ratios were 4.12 or 3.88 and I was told I should have the 4.12 if the trans is stock to the pan. Going to a 3.88 isn't much of a change. Jeff, what size rear tire are you running? |
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Post by centralvalleygter on Jul 14, 2010 0:16:07 GMT -5
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Post by pushnfords on Jul 14, 2010 21:25:21 GMT -5
Thanks! Lot cheaper than I expected. |
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Post by mrbigh on Jul 14, 2010 22:31:49 GMT -5
Great Links !!!, thank you
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Post by Jeff Troy on Jul 15, 2010 21:25:40 GMT -5
Hi, Push,
Tires are Dayton 195/70R14.
Regards...
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Post by pushnfords on Jul 16, 2010 16:25:07 GMT -5
Thanks Jeff!
I've been doing some calculations based off of Jeff's data, the tire sizes I'm looking at, and using the different 4th gear ratios. Looks like "our" Bradley would be running around 3,000rpm @ 60mph and 3,500rpm @ 70mph with the stock transaxle. A Freeway Flier transaxle would change that to 3,000rpm @ 65.1mph or 3,500rpm @ 75.9mph.
That's about $106.78 per mph over 70.....hmmmm.....
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Post by smyrnaguy on Jul 18, 2010 15:34:31 GMT -5
A 3mpg increase would make that pay for itself in 100k miles.
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Top Speed
Apr 11, 2016 10:02:15 GMT -5
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Post by connor on Apr 11, 2016 10:02:15 GMT -5
I got my 75 gt up to 120 last time I pushed it.
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Post by Dan MacMillan on Jul 17, 2017 11:43:31 GMT -5
Ok I'll bite. As some of you know mine is rather unconventional. 2.2 Subaru mid engine running the Subaru automatic transmission, 4 wheel power disk brakes. I've had it up to 100 mph a couple of times. It handled perfectly but when your ass is a scant 4 inches above the road it seems like you're doing 200. At 100 it has lots of throttle left. Mathematically it should peak out around 150. I'm not going to be the test pilot to prove it.
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...................I knew Chris was in the Guard, but I didn't know his dog was as well!! 
;D
