2.0 8V Volumex Race Engine Build - Help?

Competition engines and ancillaries - general discussion
wmausbach
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by wmausbach »

Bill,
I still have my Volumex project on the back burner (street use) but I'm looking forward to your experience. Jason Miller of Miller's Mule suggested that I use the grooved belt like all the Eaton's use. The advantage is that he can make these in any diameters. Belts are easy to get also. What do ya'll think??
Wayne in Houston
Guy Croft
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by Guy Croft »

OK in principle - but making a new front pulley for the VX unit in a different style just adds cost, there is really no need for this.

Ratio? Bill - I suggest you 'put a stake in the ground' (have to start somewhere) and run 1.38 (29/21) and then we cna move on to other aspects.

CR? I would not go higher than 10/1 but I am well known for being, er, 'conservative'. This means revised pistons I guess.

The ignition system should be admirably suited to the task. FWIW the VX (even in the higher states of tune that I have done) ordinarily runs a 'standard' atmo advance curve of 10 deg static and 34 deg total at 5500 and you should start with this and be prepared for some retarding if need be for best power. Denser mixtures burn faster and thus less may be needed though how this 'pans out' on E85 I have no idea. Vacuum is not needed.

G
tmvolumex
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Re: 2.0 8V Volumex Race Engine Build - Help

Post by tmvolumex »

Bill,
I have built Volumex engines that use large overlap cams, a higher than stock supercharger drive ratio, and a single side draft DCOE. These are hot street engines limited to 8-9 PSI of boost because of the requirement to use pump gas. With an 8 to 1 compression ratio and a 304 degree duration cam, power is in the 200 plus HP range, crank. To get to your goal of 250 plus hp from an 1130 cc Volumex supercharger, in my opinion you will have to increase the blower drive ratio somewhat. Since you have a Volumex supercharger now, I would send the blower to Guy Croft have him Xylan coat the rotors and reassemble the supercharger. The Xylan coating will increase the volumetric efficiency by reducing the leakage past the rotors and the rotors to case. This alone will increase the boost pressure. Volumex superchargers run .004 inches of rotor to rotor and rotor to case clearances so they have high volumetric efficiency to begin with. In addition, I would go with the cams Guy recommends as the cams I used in my applications do not have as large of a lift integral as Guys Cams. For a racing application, I agree with Guy and I would be conservative on the supercharger overdrive ratio and subsequent engine RPM. If interested, I can help you out with an increased drive ratio crank pulley for your application. I noticed that you are in Colorado. What elevations are you going to be racing? If you are at 5,000 feet as Denver CO is, you are going to loose a couple of pounds of boost due to the elevation. Normally you could spin the supercharger faster to compensate, but you will have done that already, so you may not be able to make up for the high altitude. A turbo is altitude compensating so it wins out there, but the turbo will experience an increase in lag while the supercharger will not experience any change in response. Depending on the race track one will have an advantage. This sounds like an interesting project.
On a side note, a Lancia 037 Stradle, (16 valve Fiat / Lancia 2 liter) made 205 hp at the crank on only 7.0 PSI of boost back in 1983. These were street versions of the world rally champion Lancia 037. They had a single 2 barrel down draft carb and a 7.5 to compression ratio. Just goes to prove that low indicated boost, may just mean the boost is getting into the engine. IE if it breathes well, it will make power.
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by MACAuto »

Tom,
Thank you for your post, to add to this discussion. I didn't know you were "that guy". I have read your write-up from back in the 90's, I believe, as part of my research, and references to your work with the VX blower, from many sources. Thanks for joining in.

After some weeks now giving this thread a rest to attend to work and to getting my sources lined up for this build, I have come up with what I believe to be a good build spec. I am still open to suggestions, as I haven't placed firm orders yet for gearing ratios, or the pistons. I WILL be doing this sometime this week, so anyone wanting to add to this discussion should do so very soon.

I have located the GCRE 3A and 2B cam set (to borrow only, so I will need a quote from GCRE, if this works). I will be going to Venolia for 10:1 compression forged pistons, with reliefs for my head with the 46IN and 40EX valves with matching porting. I have contacted Jason Miller of Miller's Mule, to construct a special alloy front pulley with the 60-2 5" crank-fire wheel fastened to the back of the pulley, and the stock sized VX 29 tooth crank cog fastened to the front of the pulley, using his sensor mount, as well, which will allow for the HPV-1 ignition to operate, and also allow the blower drive on the same pulley. The VX blower kit will be supplied with an Italian 45DCOE equipped with 28mm (also supplied with 30mm and 32mm venturis for dyno-testing), and fed with E85. Carrillo rods will be retained for this build. ARP head studs, and a Turbo head gasket will (hopefully) hold this all together. The present 16 row oil cooler will be upgraded to a 19 or 25 row element. The 3 qt accusump will also be retained.

The 29 Crank, 21 Blower gearing will produce a blower speed of 8970 rpm with a limit of 6500 rpm engine speed, which can be set with the HPV-1 ignition's rev limit setting. I don't know exactly what the boost will be with this gearing/engine speed. I haven't had anyone tell me what the VX blower will produce in psig boost at that blower speed - only to NOT exceed that blower speed. Anyone know what the blower produces at 9000 rpm in psi of boost pressure? (sea-level)

I understand fully that I will lose 20% of rated boost from sea level to Colorado's elevation of 5000' to 6000' for the 3 home race tracks we have here. The NASA championships, however, will be located at Mid-Ohio for this year and next, which I believe is at about 500' elevation. We dyno-tune with SAE correction for this elevation, so the 225WHP I need is more for Mid-Ohio than Colorado. My "official" dyno reference for competition is my shop's DynoJet chassis dyno (and is for all NASA competitors in this region), expressed with the SAE correction factor for elevation (20% higher than actual, uncorrected "mountain" WHP). In short, the readers and posters here should think in terms of sea-level WHP, and not concern themselves with where the car lives and races (where ALL race cars make 20% less power).

Please reply soon, as my window to both compete this season, and do this new engine build, requires I get off my duff and order up the bits I need to get the job finished.

MACAuto (Bill)
tmvolumex
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by tmvolumex »

Bill,
Glad to hear you are still pursuing this project. I can make a few comments, but I have no experience with the fuel you are planning to use (E85, 85% ethanol, 15 % gasoline) so I will stick with a gasoline type application.
• For a street car, pump gasoline application, 8-9 PSI boost, I would limit the compression ratio to 8 to1.
• For a race car application, race gas, 9-11 PSI boost, I would limit the compression ratio to 8.5 to 1.
• For a race car application, E85 fuel, I have no idea on compression ratio, as there are more variables to consider. IE how much additional cooling do you get from the fuel? How much more fuel combined with air does the supercharger have to pump into the engine because of the lower energy content of the fuel and the need for a richer mixture because of the E85 fuel. How much more power is required to drive the supercharger because it is pumping more mass through it?

You mentioned some specific questions for your build so I will mention some of those items, plus some others.

• I have had excellent results with Spesso, Volumex, head gaskets. I know Guy carries a different brand but I don’t have any experience with any brand other than Spesso. I have used the Spesso, standard, VX head gasket although they make a Kevlar race one also, it costs twice as much.
• Make sure the 21 tooth pulley you are planning on using was made using a gear hobbing machine. I have seen 21 tooth VX pulleys that are milled not hobbed. The teeth are very inaccurate and tear up belts. If by chance, you have a Fiat Volumex Spider pulley make sure you have the correct tapered sleeve that fits inside it, for attachment to the supercharger rotor shaft. The sleeve taper is different for the 22 tooth Lancia Beta VX pulley and the Fiat Volumex Spider 21 tooth pulley. (Thanks Chuck S. for that info).
• Automotive pitch belts (9.53mm pitch) and 3/8” (.375”) industrial belts are not the same. In addition, the pitch diameter of the pulleys is not the same. Yes, I know 3/8” equals 9.53mm but the belt and pulley designs are slightly different. Automotive belts have a thicker section, thus they require a smaller pitch diameter for the same number of teeth. Just wrap a timing belt around a 4 inch or larger diameter industrial 3/8 pitch pulley and you will see what I mean. You will not be able to wrap the automotive belt around 180 degrees of industrial pulley. If you use an industrial belt on automotive pulleys (this combination will seem to fit) you will have very short belt life, especially in racing.
• Make sure your pop off valve moves freely. The pop off valve begins to open at 14PSI. If you increase the boost above 10PSI you may want to increase the spring pressure to make sure it stays shut under boost. In the 20 years since building my first Volumex engine, I have only had a couple of backfires that caused the pop off valve to vent, but it only takes one backfire with a stuck pop off valve to trash the supercharger. IE make sure it is clean and lubricated. Put a filter on top of it also, I use a K&N breather filter.
• You didn’t ask about a clutch, but you are going to need a really good one. I have torn the middle out of 2 clutch disks with my built up Volumex engines. This is despite the fact that I was using a Valeo, Lancia 8 valve, Integrale disk. The middle spring assembly bottoms out from the torque and is literally torn out of the middle. Since that, I now use a custom built Kevlar disk and all seems OK.
• The Lancia 037 Stradle used 33 mm chokes on a 2 barrel carb, you will need at least that big, for the 225 WHP you want. If you use a higher than stock drive ratio, the increased low RPM boost makes up for any lower velocity through the larger chokes. My VX has 6 pounds of boost available at 1,000 RPM. Put the car in gear, let the clutch out and idle along, stomp on the gas pedal and 6 lbs of boost is available at 1,000 RPM and it takes right off. I have increased the SC drive ratio over stock.
• You are going to need a big header. Go big or go home as they say. The one on my Lancia is huge.
• I would take a good look at the supercharger you bought. If it looks like someone has taken it apart in the past, I would send it to Guy for a going through. If it looks OK make sure you change the grease in the rear, it is 30 years old if the supercharger is new old stock. I use Red Line synthetic gear lube in the front case. Be sure to not overfill you can blow off one of the hoses and wind up with no oil.
• Use a big, name brand air filter. With only .004” (.1mm) of clearance between rotor to rotor and rotor to case you better not swallow a rock or a nut as it will destroy the supercharger. If the filter is too small you will never make the power you want. A 1 PSI drop across the air filter is a 1 PSI drop in boost.
• Since you are mixing and matching engine pulleys make sure they are all lined up in one plane. See Guy’s recommendations for timing belts and pulleys on this site.
• For ignition I use a CD / MSD with rev limiter. Rev limiter is a must.
• The torque from the Volumex will allow you to use a lower overall RPM range, adjust the gearing accordingly before you race. Don’t forget.
• Buy the book “Supercharged” By Corkey Bell it will tell you all you need to know about superchargers, including how to figure out how to get more power out of your engine once it is up and running. See chapter 16 on testing the engine. This section covers measuring temperature increases across the supercharger, measuring pressure gains and pressure losses throughout the system. IE a 1 PSI pressure drop across the air filter is a 1 PSI drop in boost pressure etc.
Good luck,
Tom McG.
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Guy Croft
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by Guy Croft »

MODEL POST!

One of many by Tom, thanks very much for a superb and concise contribution.

I know very well that it takes a long time to form an article like that, 'knock it' into shape, edit it etc. That is even assuming you don't have to research the topic.

GC
MACAuto
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by MACAuto »

The gap in time here has been spent with Tom and I corresponding about the details of this build. He is very knowledgeable, about Volumex on the 8V TC.

I have settled on the build parameters, and have placed nearly all my orders for materials. I have made my plans time-wise for the build as well. I will be competing with the car as is, in the April and May racing events here in Colorado, with a tear-down commencing on May 16th. By then, I should have all of the bits I need in place to get a build turn-around in time for the August 20-21 local race, with a possible July 2/3 debut with the new build. Certainly in time for the NASA Championships at Mid-Ohio September 8-11.

I will post build progress on this thread, and dyno numbers when I have them. Wish me luck.

MACAuto (Bill)
tmvolumex
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by tmvolumex »

Bill,
Thanks for sharing the news on your very exciting race car project.
Nothing better than a new, high boost, Volumex race car engine, on a high performance fuel.
You are going to love the scream of a Volumex at full boost.
I will have to make a trip to Colorado this summer and see the new beast.
Glad to help out.
Good luck!
Tom McG.
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Guy Croft
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by Guy Croft »

Good to see this moving forward in Bill's skilled hands, look forward to updates!

G
WestoE
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by WestoE »

Bill

I have to declare an interest in this thread as I am building 2 Supercharged and Fuel Injected 8V engines. The first is using the VX Supercharger 3A inlet cam and stock exhaust cam on 7.5:1 compression with standard drive ratio i.e 29 to 22.
The second is using the Volumetrico Supercharger with 3A inlet cam and stock VX exhaust cam on 7.5:1 compression with a 29 to 27 drive ratio. N.B. The road going Volumetrico had a 29 to 32 ratio.
Both of these units will have mapped ignition and fuel injection in board from the SC with a 45mm throttle body direct mounted on the blower body fed with cold filtered air.

Both engines have GC prepared 44 36 valve cylinder heads and forged pistons and conrods and will be run on 97octane fuel as a minimum. I expect to finish the build and install of the VX unit in my Montecarlo in late October 2011 when I will be able to share to rolling road figure from re-mapping the Emerald ECU currently controlling my Naturally aspirated fuel injected 2000 8 Valve engine.

It is great to have picked up so much knowledge from this thread and I look forward to seeing the results from your build.

Eric
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wmausbach
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by wmausbach »

Eric,
We all look forward to your results. I will say though that the F.I. will be a LOT more complex to tune. I would suggest going the carb route initially for two reasons;
1) Unless you are prepared for many dyno runs with an experienced tuner, the cost will be beyond the means of an individual. You can always do the F.I. as a second step after the shorter development time with carbs (The previous examples use carbs, listen to people that have done similar projects). I seriously doubt the small increase in HP ( IF you get it sorted) will be worth the cost.
2) What the suck through carb does is allow the incoming charge to act as an intercooler. Lampredi knew this and used to great effect in the VX road cars and the 037's. Increasing pressure for generating more power for race applications forced F.I. and water injection. As Tom stated, the 037 road car with 7 psi of boost and a 40 mm two barrel carb produced 205hp ! Maybe someone else out there has F.I. the Volumex/ Volumertrico, other wise you will be on the "Bleeding edge".
Ciao
Wayne
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by MACAuto »

After more than a year, I am back to update the GC Forum reader with results. You might have thought I would never make this posting, but I DO have actual results on my 8V VX build. If there is sufficient interest, I can provide more detail. So, what took me so long?

As I left this thread on April 6th of 2011, the course of events leading up to this posting were as follows: The actual build of the engine bottom end was uneventful. I had the custom 10.4 CR pistons made by Venolia, which took longer than I anticipated, putting my build late into the racing season.

Once the engine was built up, I had to have a carbie adapter made to fit up the 45DCOE, made to fit this engine into a Spider 2000 chassis. No big surprise, as I had thought, nothing on the intake side would fit in the Spider chassis without extensive modification to accommodate the blower, and the Weber sidedraft, with velocity stack. For one, the adapter had to be made in a wedge shape to angle the DCOE forward to clearance the shock tower, as the mounting intrudes into the left front wheel well area. An airbox was constructed to cap off the opening in the wheel well, and to feed air to the box, from the headlight opening, which also provides fresh air for the carbie. Very tight clearances exist between this airbox, and the front racing tires. The box design went through 3 shape changes to allow sufficient air flow and to still allow enough right turn steering clearance. Whew! Weeks and weeks of work, and one severely damaged 23X9.5X15 Hoosier racing slick.

Dyno testing was disappointing, yielding only 190WHP (approx 223 crank HP with 15% drivetrain loss), so I knew more tuning/testing was going to be needed. The car was raced on one race weekend late in the 2011 season for a single day. By the end of the day, the engine would no longer run, and was found to have 4 bent/burnt exhaust valves. In hindsight, I believe that I had over-revved the engine late the season before, when it was still N/A, when I missed a shift on a race start. Back to the shop, engine out, head off to my head guy for new custom EX valves. End to the 2011 racing season, and more development needed moving forward into 2012.

Issues with tire clearance and the need for a new header consumed the off season. It was my thought that I had rushed the car to the track in 2011 - a racecar very much more complex than the N/A edition of the same car. Serious work and development needed to be done, to make this VX racer achieve the desired power, and to be reliable as a racecar. Fabrication resumed on the airbox, and a new header was designed and built, by my new staff fabricator. Midway into the off-season work, I had to let the old fabricator go due to differences of opinion on the header and airbox design and fabrication, and almost every other fabrication project for the business. Too bad, as he really knows metallurgy, and makes terrific welds. He just butted heads constantly with the boss (me), and everyone else in the shop. This had caused severe delays on shop business, and going into the 2012 race season, months had passed where the racer header remained a flange, and collector - but no connecting primaries. Our new fabricator is quite different. I instructed him on what I wanted, and had a perfectly fitted header 3 weeks later, from scratch, along with a modified tunnel to route the header over and behind the steering idler (remember - left hand drive).

Most of the 2012 season was used to develop the fitment of the engine in the engine bay, and to tune for more power. Cams were swapped in and out (4 different combinations), and dyno tuning revealed that the 45 DCOE required monster jets to work with the E85 fuel. The entire fuel delivery system has been revamped with multiple fuel pumps to assure no fuel starvation, and to provide sufficient and consistent fuel pressure to feed a 45 DCOE that uses 275 main fuel jets! A fairly complete rebuild of the carbie included new 5.0 secondary venturis, extra drilled clearance for the idle jets, and huge needle and seat to keep the bowl filled. 35mm height velocity stacks hold a Pipercross foam filter, and provide just enough clearance inside the airbox.

The original goal was to get 225WHP (265 crank HP). Just today, the latest chassis dyno tuning produced 220.69 WHP, and 186.30 Wheel Torque (260 crank HP, and 219 crank torque, assuming 15% drivetrain loss). Very close to my target goal from a year and a half ago. I am very pleased. The racer will be on track this weekend for only the third time VX equipped, and I am looking forward to the results. The power on track is impressive, very linear, for a car with a racing weight of 2050 lbs. - very fast. It has to be, as I am classed with FC RX7s, Corvettes, and 5.0 Mustangs! Lighter is faster, and boost is the equalizer. VX fun.

Comments and questions are welcome, and details (not all of my secrets!) will be available to those interested, by way of the continuation of this thread. My sincere thanks go out to my dyno-tuner, and to tmvolumex, with whom I consulted on the engine tuning. Thank you Nick, and Tom!

MACAuto (Bill)
Guy Croft
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by Guy Croft »

Outstanding work Bill and thanks for sharing the exciting developments! I do like these kind of posts - readable like a good book..

MODEL POST

G

PS any photos?
Guy Croft, owner
tmvolumex
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by tmvolumex »

Bill,
Terrific news, thanks to your hard work and perseverance, you have met your impressive goal.
Time to suck the doors off some RX7s, Corvettes, and 5.0 Mustangs.
It’s been great swapping ideas and watching from the sidelines.
Good luck in your upcoming races,
Tom McG.
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Re: 2.0 8V Volumex Race Engine Build - Help?

Post by 037_beta »

Bill, this is brilliant work and exceptional results. I have been following this thread from day one. I have my own Volumex build in progress. One question that jumps out is about the intake manifold. Are you running the standard Volumex intake manifold? Have you noticed any differences in the fuel burn and exhaust temperature across the cylinders?
Book #188
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