|Vintage Volvo Performance, part 2
In the last installment we briefly reviewed the history of Volvo performance and alluded to advances that could transform the performance of our vintage Volvos. This installment will review some of my current street car efforts in that direction including suspension improvements and a decision on an engine swap or supercharging.
The Current Street Car Project
In the spring of '99, I was offered a '68 1800 as a parts car. My son was 16 and about to get his license. We both thought the 1800 was too good to be retired for parts. Bolting on the few things it needed to become a driver -- carbs were the main item -- we had fun driving it around. Stiffer springs and shocks were an immediate modification, as were replacement of two lower ball joints and the left side lower A-arm bushings. It was fun to drive with no other changes. At my wife's prodding it went into the garage for a paint job, which evolved into a quick but rather extensive restoration project when we discovered what was under the bubbles in the paint. After three weeks of welding and cutting, cutting and welding, filling, sanding, and a quick paint job, the car was now at least presentable, but the improvement bug had hit. I couldn't leave it alone. I had to make it better. My son ended up driving an '83 240 wagon, which was more appropriate anyway for a new teenage driver, and the 1800 became the latest test bed for street performance modifications.
When I first put the car on the road, I installed an old set of Koni shocks and IPD springs -- basically 1960s technology. These had been on the 1800 that became my vintage racecar and had been used during its first year of racing, and wouldn't cost anything. They lowered the car about an inch and improved the handling a great deal, even with stock wheels and tires. But the car was not as stiff as I would like in the corners while being a little too stiff over bumps and even minor road irregularities. We tried some other single rate springs but were not satisfied. Stiffer springs hurt the ride and softer springs hurt the handling.
I had been looking into progressive springs and this became the perfect opportunity to test them out. Progressive springs have been around for a long time; most of Volvo's R-Sport springs were progressive, but are usually more expensive than single rate springs. They consist of coils with different spring rates in the same spring. Most aftermarket spring kits for current sports sedans being marketed today include progressive springs as they allow a stiffer spring rate to control roll in cornering without adversely affecting ride quality.
After trying about a dozen combinations, we came up with a progressive spring setup that met our requirements. Surprisingly, we were able to get improvements in both areas. Comparison tests showed that it significantly improved the handling and the quality of the ride. We used the progressives in front only, partly because of the difficulty and expense of getting progressives that would fit the rear, and partly because it turned out they weren't needed. The rear springs are pretty soft anyway -- stock is less than 100 lbs. per inch -- and stiffening this up to the 120-130 lb. range didn't seem to hurt the ride at all. The combination worked well with the old Konis after a little adjustment, and was even better with a set of Bilsteins.
Because of the degree of static compression of the soft coils, the ride height ended up a little lower than we had planned, but this was solved easily with a shim-type spacer. This turned out to be an advantage as the combination of the comparatively short spring and spacers allows the same spring to be used for a number of different ride heights based on driver preference. We ended up setting up our car 1" inches lower than stock in the front and an inch lower in the rear with stock height tires.
Boris Kort-Packard was the first customer to try them. He wanted a spring that was stiffer than the ones he was using to help in his weekend autocrosses, but did not want a spring too stiff for everyday driving. He reported that the springs are an improvement in both ride and handling, as we expected.
Although I am sure I would go with a stiffer-than-stock front bar for the occasional autocross, at this ride height, and for purely street driving, we were satisfied with the stock sway bar. The problem with going to a stiffer sway bar is that it stiffens the spring rate when only one wheel is deflected over a bump. In the future we will go to an adjustable bar in the front.
Replacing the rear control arm bushings with a combination of stock rubber and polyurethane for the big end completed the handling package, at least for the time being.
Now for the Power
The next consideration was straight line performance. The engine that came in the car, of unknown history, would push the 1800 to 60 MPH in 13.5 seconds -- right in line with contemporary road tests of the car in the '60s. We considered the standard mods which would bring 0-60 times down into the 8-9 second range -- head porting, header, cam, performance exhaust -- but decided to push the limits. Following a Porsche Boxster on California's Route 1 through Big Sur (unfortunately in a rented Taurus wagon) got me dreaming again of similar performance for the 1800 and the project got the code name of "Boxster Beater."
An Engine Swap or Supercharging?
After considering and rejecting turbocharging the B20 (more on this later), initial planning focused on engine swaps. The idea was to put a contemporary Japanese DOHC 2 liter 4 cylinder, with fuel injection or Weber carbs, with a 5 speed, in an 1800. Using 4 or 5 valves per cylinder, variable valve timing, and the best of current technology, there are several 2 liter engines available from Toyota, Nissan and Honda that produce from 180 to 200 HP normally aspirated. In the U.S. there are the slightly larger Olds Quad 4 and others. The resulting car would be similar to the car Volvo could have produced if it had continued to develop the 1800 with a version of its DOHC rally head on the B20. Being the same size and weight as the B20, it would not upset the balance of the car and would not require any body modifications. Sharing a contemporary engine of similar technology and design, it would compete favorably with numerous modern, popular sports cars. Low mileage used engines are readily available as imports from Japan at very reasonable prices and are widely used in engine swaps. Further, there is a great deal of performance equipment available for them with more being developed almost daily.
But the idea was also to do this as simply as possible (always follow the famous KISS engineering principle), and do it in a way that it could be easily duplicated by or for others. Engine swaps are only simple in concept, never in the details. As the engine swap project progressed, it became clear that it was entirely feasible and would be a really neat project, but it was also getting more complicated and expensive. An article on engine swaps in the June 26th issue of AutoSpeed, an Australian online car magazine available at www.autospeed.com, makes this point. "It's very easy to fall into the trap of looking at a bare engine (complete with gearbox), seeing the price, and getting very excited. But you need to multiply its price by probably four to six times by the time it's installed and is running well." With modern engines there is always the question of the electronic engine management system. If you eliminate it in the interests of simplicity and install carbs, you are likely to lose most of the advantages of the modern engine that produced the high HP output. To get the power back you have to make additional modifications, that, while entirely feasible, can be very expensive on a modern DOHC engine.
Another desire was to retain as much of the original car as possible, and I was not sure what the general reaction among Volvo owners would have been to a Japanese engine and transmission in a Volvo. In comparing likely performance results and costs to other options, a conversation with Bob Griffith of BHP convinced me that there were other ways we could get comparable or greater performance, at a lower price, in a manner that could be more easily duplicated by others. And if we could retain the original engine, we could keep much more of the vintage Volvo character of the car. I would still like to do a DOHC swap. If anyone is interested in having it done on their car, please let me know. I have put together most of the details, sourced the parts, etc., and even have three of the five speed transmissions to go with the engine. If there is interest, I will cover further details of this option in a future article. (In a current book on engine swaps, there is a photo of a 544 with a Japanese DOHC four, but no details. Info and additional photos would be appreciated if anyone knows anything about this car.)
The Choice of a Supercharger
Vintage racing has taught us to look to modern technology to make improvements without changing the basic character of the car. One of the biggest current trends in performance enhancements is the return of supercharging, both as original equipment and in aftermarket kits. There are thousands of supercharger kits being sold for everything from Chevy trucks to Mustangs, BMWs, Toyotas, Hondas, etc. Many are sold as a weekend bolt-on. Many of you will remember the old Judson supercharger sold for Volvos. (Check out the article in a recent issue of Grassroots Motorsports on these units, although it doesn't go into the Volvo application.) You may also have heard that they were kind of neat but not reliable. There were oiling problems and significant vane wear. Technology has far outstripped the Judson and there is really no comparison in both performance and reliability.
Why a supercharger rather than a turbocharger? Technically, a turbocharger and a supercharger are the same thing. What we call a supercharger is belt or gear driven, while the turbo-supercharger is exhaust gas driven. While there is only one basic design configuration of the automotive turbo-supercharger, and some superchargers share the classic turbocharger turbine wheel compressor design, there are many different supercharger configurations, including vane, screw, lysholm, etc. Many are derived from industrial air compressors and adapted for automotive use.
A significant advantage to superchargers is that they require fewer modifications then turbo-supercharging. With supercharging, only the intake is involved. With a turbocharger, modifications to both the intake and exhaust manifolds are necessary, and to make serious power, you also need an intercooler. The more plumbing that is involved, the more space becomes a problem. Superchargers produce more torque at lower RPM than most turbocharger setups, and usually eliminate the classic "turbo lag" while exhaust gas pressures bring the turbo up to speed With a belt driven supercharger, boost output can be easily controlled by changing the speed of the supercharger in comparison to engine speed by simply changing drive pulley sizes. For ultimate power the turbo would be the choice, but for low end torque and throttle response, the nod goes to the supercharger. As it is not in close proximity to hot exhaust gasses, the supercharger runs cooler and normally produces a cooler discharge. This often eliminates the need for an intercooler. And just consider the challenge of trying to fit a turbocharger and all of its exhaust plumbing onto a B20 in an 1800. At least on a 240, the intake manifold is on the other side of the engine. (Well, it turns out that a North Bay Volvo Club member has taken up this challenge and has installed a turbocharger on his 1800. I hope to have more information in a future installment.)
Reliability of the supercharger unit is no longer a question as units are rated at over 22,000 hours at 15,000 RPM, the equivalent of over 1 million miles at 60 MPH. They would not come on Mercedes cars, long haul trucks, or diesel locomotives if they were not reliable.
A little known plus for us Swedish car fanatics is that the supercharger widely regarded as the most efficient and reliable is made in Sweden. Solving the performance problem for older Volvos by utilizing another Swedish product just seemed right, and these two considerations clearly dictated the choice of which supercharger to use. But even being a Swedish unit, there are apparently no kits for old or new Volvos. Well, there will be if I have my way.
After several months of research and work, a prototype is now installed on my '68 1800 test car. Most of the time was spent milling and re-milling an intake manifold and other parts to adapt the supercharger to the engine and a Weber carb. Once the components were completed and modified to eliminate clearance problems, the actual installation, including the drive belts, pulleys and the oiling system, took several hours and required only a set of wrenches and various screw drivers.
Refinements will require some testing, but initial results are very encouraging. Zero to 60 had been 13.5 seconds with the stock 1800 engine, SU carbs, and stock exhaust. After some tuning, we tried a 0-60 run and got 7.54 seconds, G-Tech timed. This was on the second run with 10 lbs. boost. (I was also surprised when the G-Tech flashed a quarter mile time of 15.3 seconds at 85 MPH, as I had backed off after the 0-60 and had no intention of running the quarter.) This performance was without any mods to the exhaust, head, cam, etc. Additional tuning should lower the time further, and remember, this is with a B18.
In the interests of truth in advertising, I must reveal that I did use an aftermarket ignition with a knock sensor and timing retard as part of the testing package. Without this system, I could never have run 10 lbs. boost on street gas and would never have known how much to manually retard the ignition timing. For test purposes, the setup included an air/fuel ratio and knock/retard monitor, and this eliminated a lot of trial and error time in tuning the engine. (So far it has also eliminated that part of the trial and error process where the engine blows up.)
Plans are to continue to test with a stock engine to see what the average Volvo owner could expect from a weekend bolt-on and then continue modifications, both to the engine and the supercharger installation. For a basic application with no add-ons or modifications, boost will probably be limited to 5 lbs. -- the equivalent of the 1.3 Bar on turbo boost gauges. Most of this testing will be on a B20, as most owners interested in performance have upgraded by now, and the better breathing B20 head opens up the door for significant increases in flow and performance. A header and free flowing exhaust will be another basic requirement. Further tests will be monitored by frequent runs on a Superflow chassis dyno and the test results reported here.
These various steps should allow us fully to explore the performance potential of the system. Considering that there are 200 HP MGBs using similar components, we are confident we can get 180 to 200 HP with modifications. Engines modified specifically for supercharging should have even greater potential. Only testing will tell what power level or degree of boost a basically stock engine will tolerate without modifications. We plan to try 8-10 lbs. of boost with the stock engine, and the B20 with its stout bottom end should be an excellent basis for high boost applications. Once we determine the limits of the stock engine, we will build an engine designed specifically for high boost and see what we can get out of it with 15+ lbs. of boost. Expectations for the modified, low compression, high boost engine are for well over 200 HP, but this will require a good deal of testing and development work.
At the same time that we are testing the prototype, I am working to have castings made of the necessary parts so that a kit can be produced. If you have an interest in this project, please let me know so I will have an idea how many sets of casting to have made. The first version of the kit should fit the 544, 122, and carbureted 1800s and 140s. Next year we will explore doing versions for the fuel injected cars including 240s. It won't exactly be inexpensive, with current estimates at between $2000 and $3000 for a complete bolt-on kit, depending on what components are included. But it will be a comparatively inexpensive way to increase engine output by 40% or more, and the only way to do it yourself over a weekend. There will be several choices here as higher priced versions of the kit with additional components will be more sophisticated and have higher horsepower potential using the same basic supercharger unit. This will allow someone to purchase a basic kit at a minimum price and then develop it over time into a higher power system. It will use the same supercharger as used in kits that are widely sold for Miatas and BMWs at $3000 and $5000, respectively. We may be able to reduce costs if significant numbers are involved. In any case, it should finally answer the frequently asked question of, "What can I do to get 40-50 more horsepower?" In addition, with appropriate suspension modifications, it will allow anyone to have a vintage Volvo with contemporary sports car performance.
The next article will discuss some supercharger/turbocharger basics and will get into the details of the supercharger I am using, how it is installed, and the results of its performance testing. If you have a project, completed or in the works, involving a supercharger, turbocharger, or engine swap into a vintage Volvo, please let me know so that we can include information on your project in future articles. You can call at (315) 478-1229, but communication will be most efficient if you e-mail to email@example.com.
Part one | Part three | Part four | Part five
Easy-print version of this article