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GTV
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Joined: March 27, 2004
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Location: Si'ahl
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 Posted: Sun Sep 16, 2012 7:32 pm Post subject: Low Octane Fuel & Higher Performance |
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I've got a 2332 that I want to (re)build for a road tripping bus. All of my previous builds have been geared towards getting the most out of a particular combination (hence the use of 91 octane), but not this one. I want it to run on 87, get good mileage, and make plenty of low rpm torque. Never revved past 5k rpm. What would you build given those parameters? What cam, heads, carb(s), and most importantly, compression ratio would you set it up with? Low compression will be difficult to achieve with such a large engine, unless I hemi cut the heads, which I am NOT a fan of (but that's another topic), or run gobs of deck height which is worse. I've got a handle on keeping a ACVW engine cool, so lets avoid getting into that subject if we can 
What do you think?
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Eaallred
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GTV
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| Posted: Sun Sep 16, 2012 7:56 pm Post subject: |
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Ha! Easy for you to say The whole point of this build is to be inexpensive to build, and inexpensive to operate. It would take a whole lot of fill ups before I made up the difference for $650 of pistons. Let me clarify that I'm not being "cheap" with this build, I'm trying to get back to what a VW is supposed to be in the first place, reliable and inexpensive transportation (it's a new concept to me, too)... And in this case, a bit more power on tap.
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OLD VW NUT
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| Posted: Sun Sep 16, 2012 8:20 pm Post subject: |
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87 octane and high compression are mutually exclusive - pick one or the other or increase deck height. I'd shoot for around 8.5 compression ratio and use dual 40IDF's with 32mm venturis and an Engle W110 cam. Heads don't have to be anything special for a low rpm motor. Should produce plenty of torque from idle to 5k rpms.
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[email protected]
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| Posted: Sun Sep 16, 2012 8:38 pm Post subject: Re: Low Octane Fuel & Higher Performance |
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dish the pistons, you can get ~6cc more that way. Run .070" deck max (NO MORE). Run a bigger cam, it will tolerate more CR than a puny can will.
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GTV
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| Posted: Sun Sep 16, 2012 9:01 pm Post subject: Re: Low Octane Fuel & Higher Performance |
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| [email protected] wrote: |
| dish the pistons, you can get ~6cc more that way. Run .070" deck max (NO MORE). Run a bigger cam, it will tolerate more CR than a puny can will. |
About dishing the pistons, I've done it before and got about 7cc out of a 94. The thing I didn't like about it is the dish was round, and the chamber was not... much of the quench area became ruined, IMO. Ideally the dish needs to mirror the chamber, but I'm not sure how to easily accomplish that.
I agree, tight deck is best. How much bigger on the cam? Even a 110 cam like suggested above will make power past the rpm I need to go. The last motor I built (1679) with a stock cam and 1.4's pulled well to 5,500!
Or would it be better to keep the cam on the small size and trade out my 84 crank for a 78? Would make getting the CR lower easier...
I should mention, I would like to keep it simple and use a cam designed for stock 1.1:1 rockers.
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mark tucker
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| Posted: Sun Sep 16, 2012 9:30 pm Post subject: |
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| bath tub /dish pistons with .040 deck , 90-9.5 cr, and the right cam should do fine. |
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Alstrup
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| Posted: Mon Sep 17, 2012 1:40 am Post subject: |
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Well, if you want a decent engine, cheap, I kinda see the same solution to the problem as Eaalred. If you go into swopping cam and crank you have soon spent about the same amount and a lot of time.
But you failed to menthion:
What cam are you running now
What CR ?
What heads ?
What carbs ?
Next WHAT BUS ?
Also why do you want to run on crappy 87 octane ? - I´m pretty sure that the reason is that you dont want to fill expensive fuel in your road trip vehichle, because its expensive. Well yes, and no. If you build your engine to accept low octane fuel, it WILL NOT be able to pulls as much due to less torque and generally less eficiency. If you build it to accept medium or high grade, it will be able to pull more, meaning less throttle down the road, meaning the same or BETTER fuel efficiency.
I have the best results with building bus engines for medium grade fuel (which is Euro 95 octane, about equivallent to 90 US)
T |
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GTV
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| Posted: Mon Sep 17, 2012 5:39 am Post subject: |
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Thanks Torben, I always look forward to what you have to say. I bought the engine as a long block, I've never ran it myself. It has a Web Cam 218 in it now (242°@.050", 280° total, .414" lift at cam) which to me looks ok by the numbers, but the lift is a little more than I'd prefer (I'd like to use single HD springs if possible). The heads are Street Eliminators (why they are with the small cam is a mystery to me), but they will be sold off and a pair of VW casting heads will be put in their place. I do not know the current CR, but I assume it is on the lower side as the chambers have been hemi cut. I believe the engine ran a turbo in it's last life. So that is why I'm open to suggestions on the cam, heads, carbs, CR, etc. The bus in question is a 65 Standard, it will have the reduction boxes removed and will have 4.12 Beetle gearing. Nothing special.
I'm willing to sacrifice power if it means I can run 87. Making this one about the journey, not the destination
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mark tucker
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| Posted: Mon Sep 17, 2012 9:40 am Post subject: |
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| so if the higher octane will cost more but get better mpg and motor will like it better and last longer with fewer problems you want to run cheep fuell,go for it,I think 11:1 CR should make good torque to pull a buss, and put in a loud stereo with the $$ you save and crank it up!!!dont forget the power pully. |
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Bashr52
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| Posted: Mon Sep 17, 2012 11:44 am Post subject: |
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I'm going to just throw an idea out here, but what about a set of dual plug heads? You should be able to keep a good compression ratio but get a good burn on lower fuel........
Although you said cheap and easy  |
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Alstrup
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| Posted: Mon Sep 17, 2012 4:06 pm Post subject: |
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| GTV wrote: |
Thanks Torben, I always look forward to what you have to say. I bought the engine as a long block, I've never ran it myself. It has a Web Cam 218 in it now (242°@.050", 280° total, .414" lift at cam) which to me looks ok by the numbers, but the lift is a little more than I'd prefer (I'd like to use single HD springs if possible). The heads are Street Eliminators (why they are with the small cam is a mystery to me), but they will be sold off and a pair of VW casting heads will be put in their place. I do not know the current CR, but I assume it is on the lower side as the chambers have been hemi cut. I believe the engine ran a turbo in it's last life. So that is why I'm open to suggestions on the cam, heads, carbs, CR, etc. The bus in question is a 65 Standard, it will have the reduction boxes removed and will have 4.12 Beetle gearing. Nothing special.
I'm willing to sacrifice power if it means I can run 87. Making this one about the journey, not the destination |
Ahh, see, you should have menthioned this in the first post, as it is vital information. (To me anyway)
Now. The Web 218 is a VERY GOOD cam for busses. Provided that it is ground on 108 LC (You can check by pulling the oil pump and look for the LC nr at the cam. - Yes it lifts rather high, but the acc & decell. rate on the toe and heel are not even as harsh as the everso popular W110. AND you can rev to 6000 rpm without trouble with off the shelf valve train parts (and sgl HD springs) as long as you select with care. With stock valves, Ti retainers and ACN ally PR´s and that cam I have engines out that revs to 6700 with sgl HD valves shimmed 0,040"
Since you have options with the heads, and you do have some cc´s to feed, I´m split between a set of Timms stage 1 & 2. I have seen good results with the stage 2 heads on 2 liter engines with anything from W110 cam to Web 86b. And the last 2275 split bus engine I dynoed (told about in another thread) pulls 158 hp and 225 Nm torque with only 9-1 CR.
But with the 218 and 87 octane fuel I think you need to lower the CR to about 8,2. That WILL cost you some torque, which the stage 1 heads MAYBE could help reduce due to higher air speed at lower to mid rpms.
So if it was me, I would take the stage 2´s because I would like to have the rpm power under my right foot when I wanted it.
But if the choice is to have most usable lower rpm torque and sacrifice some powergains above 4800 Approx the stage 1´s might be a better choice.
Theoretical the stage 1 heads can deliver air to about 160 hp in good order, but with a relatively short duration camshaft that is naturally not gonna happen. - Assuming that you can hold an intake efficiency of about 103% the stage 1´s and 8,2 CR should give you roughly 140 hp @ 5300 and 200 Nm torque @ 3400. But almost flat from 2 to 4 grand.
The stage 2´s will only give you minimal more power but will, as menthioned make the engine pulls more power in the 4 to 6000 rpm area.
having the option of buying new heads, the CR problem suddenly becomes almost non existant as most heads have huge chambers off the shelf. So even a small dish in the pistons, that keeps the outer dia. within the chamber sides, suddenly goes a long way.
Carbs. - Well, 40 Dells would give you killer efficiency, but would most likely also take some time to get right with all that cc sucking. That messes with the transition area. 44 IDF´s would most likely extend the powerband a bit. Powerwise there will be very little difference, especially if stage 1 heads are used.
The rest is up to you.
T |
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raygreenwood
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| Posted: Mon Sep 17, 2012 5:12 pm Post subject: |
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Personally....I do not see the use of premium gas as a real expense at all.
Even if this is your daily driver and you pull down 500 miles a week. I mean think about this for a second.
Its running about .25 cents a gallon more. On a 10 gallon fill up...that's $2.50. Lets be generous... .30 cents a gallon more at most. Thats $3 a tankful more. Even if you fill up 1.25 times a week....five times a month....thats $15 a month. Thats $180 bucks a year. Thats 49.31 cents per day.
I do not see the expense. I drink $30 bucks worth of beer a month....as do most.
Build it to run efficiently and use premium if necessary. Its just not a worthy expense to plan hard around at .49 cents per day. Ray |
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craigman
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| Posted: Mon Sep 17, 2012 5:36 pm Post subject: |
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I just don't get it either why people are afraid of running premium gas. It's only a few bucks more a fill up.
To me, the benifits outwiegh the extra few bucks.
I say bump it up!  |
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Sharig1979
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| Posted: Mon Sep 17, 2012 6:11 pm Post subject: |
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Running premium pump gas doesn't sound too bad. From everything the driver guys I know tell me they swear that little bit in extra fuel costs adds enough in performance and longevity to be worth while. Don't dismiss premium gas as an expense. If tuned properly you may even get better milage to offset the price per tank.
Heck, we still have to dump lead additive into the 912 and 914 and from memory I think that outweighs the difference per fill than premium.
I'd love to build an engine that didn't need 20w50 full syn and 110 octane. Premium gas is 7-8$ a gallon cheaper than track fuel and standard oil is 3-4$ a quart cheaper. I don't complain when it's spooling, screaming and throwing me back in the seat.
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1968 Beetle, Class 11 build
1969 Beetle, New build. 1915 Turbo, EFI.
1969 Beetle, *Old build. 1915 Turbo.
~118 mph on the salt at WoS 2012, 7k in 3rd, can't wait to figure out how to drive that engine on that stuff.
1972 914/4, 1.7
1977 911S 2.7
1991 GTI 1.8 8v, 4speed-Sold |
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Sharig1979
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| Posted: Mon Sep 17, 2012 6:15 pm Post subject: |
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Dang. I almost talked myself into filling up with premium every time. If e85 wasn't so cheap I probably would but eh thats parts money.
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1968 Beetle, Class 11 build
1969 Beetle, New build. 1915 Turbo, EFI.
1969 Beetle, *Old build. 1915 Turbo.
~118 mph on the salt at WoS 2012, 7k in 3rd, can't wait to figure out how to drive that engine on that stuff.
1972 914/4, 1.7
1977 911S 2.7
1991 GTI 1.8 8v, 4speed-Sold |
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vwracerdave
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| Posted: Mon Sep 17, 2012 6:15 pm Post subject: |
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There is no reason you could not build an efficient daily driver engine to run on 87 octane pump gas. On a heavy Bus I would not start with a 2332 cc
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Sharig1979
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| Posted: Mon Sep 17, 2012 6:49 pm Post subject: |
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| vwracerdave wrote: |
| There is no reason you could not build an efficient daily driver engine to run on 87 octane pump gas. On a heavy Bus I would not start with a 2332 cc |
Where do you start if this is the objective? I come from a world where fuel mileage was never a concern. It seems to be a regular concern in the VW world where a similar base engine can be driven as daily transportation. All the automotive math and theory I ever bothered learning was about power, where and how, but fuel efficiency was never a part of that.
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1968 Beetle, Class 11 build
1969 Beetle, New build. 1915 Turbo, EFI.
1969 Beetle, *Old build. 1915 Turbo.
~118 mph on the salt at WoS 2012, 7k in 3rd, can't wait to figure out how to drive that engine on that stuff.
1972 914/4, 1.7
1977 911S 2.7
1991 GTI 1.8 8v, 4speed-Sold |
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GTV
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| Posted: Mon Sep 17, 2012 6:57 pm Post subject: |
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Like I said before, I've built many VW engines over the years designed for 91. I'm not afraid of it And thank you for the math lessons, but I'm already quite good at it. For a multitude of reasons I want to give 87 a try, so that's what I'm a gonna do.
THANK YOU TORBEN! That's a grip of good information there. Good to know the cam I already have is a solid choice (I'll of course measure it out first).
So, single HD springs are safe to run with that cam, 40mm valves, alloy pushrods, and Ti retainers? 8.2-8.3:1 sounds quite doable with a dish in the piston.
I'm torn between heads myself... My last set was done by Tims, and although the portwork (and power) was great, the valve heights differed by up to .035", and there were no shims under the springs to protect the heads. For what I paid, I expected more. I ended up paying again to have them set up correctly. I also see they are now using China cast heads now... ehhhh 
For the money, I'm tempted to get the Los Panchito heads from CB.
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DarthWeber
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| Posted: Mon Sep 17, 2012 7:50 pm Post subject: |
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GTV, don't overlook the L5 heads from Darren Gurrolla @ DRD:
http://www.drdracingheads.com/xcart/DRD-L5-CNC-ported-type1-heads-92mm-bore.html
I'll just throw this out there FWIW, for a Bus that will see a lot of highway miles, I'd ditch the 94's and install a set of thick wall 92mm P/C's. Just a thought for better long term reliability.
Sharig, I would start by doing a bit of reading and research such as the Hot VW's Mileage Motor tech articles found @ CB Performance:
http://www.cbperformance.com/articles.asp
and also look up info on Keith Rusher's (krusher) 1800cc build. His engine was built by DRD and get's a claimed 30 mpg in a Bus. Here is his dyno sheet:
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| Mitey62 wrote: |
| Swapped the Compufire for a Bosch blue and some points I had sitting around, started 1st crank. Took her out for a drive, pulls harder, more RPM, and runs smoother. I think I'll be sticking with points from now on. |
| RockCrusher wrote: |
| JB weld the case halves....that'll keep the fretting to a minimum. |
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