Autocrossing a TVR

Table of contents:

Introduction

Autocrossing is a great way to enjoy owning your TVR or any sports or GT car. For those of you who aren't familiar with autocrossing, it is a "non-competitive" event (meaning there is not "fender-to-fender" competition), where you drive your car (one at a time) through a pre-designed course marked with cones and are timed, usually to the nearest 1/1000 of a second. The sanctioning body (in the USA it is often the Sports Car Club of America which is called "SCCA") has rules and classes that are defined due to the results of events from prior years and the technical statistics of the various cars. See "resources" to download a .pdf of the SCCA rules.

There are various classes that attempt to put cars with the same potential competing against each other, with varying success. These classes are grouped together based upon how stock a car is.

Stock classes (named H-stock through A-stock and Super Stock and abbreviated HS, SS, etc.) are for cars that have few modifications to the car. Basically, only items you would modify for safety or for common street use that don't make a huge difference in performance are allowed.

If there are enough cars in a class (usually two or three), the actual time it takes to run the course determines the winner and placement in class. Usually the entrants get three to eight runs and the best one counts. If there are not enough cars in the class to qualify as a class the class is "bumped" into another, faster class. But then the class is scored on an "index", which is a multiplier for each class. The "indexed time", produced by multiplying each entrant's time by the index for their natural class is used to score the class. The indices are determined by last year's results nation-wide. Perhaps they are fair. But then unless you have the fastest car in any class, the index will probably not be your friend in winning an indexed class!

There are several special awards given at autocrosses, including FTD (Fastest Time of the Day, given to the person with the run that took the shortest time of anyone), FTDI (Fastest Time of the Day Indexed, given to the person with the smallest indexed time) and sometimes FTDIS (Fastest Time of the Day Indexed on Street tires), given to the person with the smallest indexed time and on actual street tires -- usually with a tread wear rating of 160 or more). As you can see, tires are an important part of autocrossing!

How does this apply to TVRs?

Since TVRs haven't been imported for a long time (1987 -- 20 years ago) and were made in such small numbers, TVRs have been pretty much ignored. TVRCCNA member Bill Sanford took second at the nationals in C-Stock a few years ago in a 3000S, but other than that, autocrossing has pretty much been a place TVRs don't go. After Bill took 2nd place they moved ALL V6 TVRs to A-Stock! So, we could run our 145 hp 280is against 330 HP Corvettes, Loti, and some other really fast cars! Thanks, Bill! They did move all TVR V6s to B-Stock last year, but it is hardly better. Let me know if you think the Nissan 350 track car would be easy to beat in your 280i...

The SCCA revised their rules a few years ago and basically removed very low production cars from stock classes. The cutoff was 1000 of a particular model a year, which TVR has never met. The new TVRs might make that cutoff, but until they are in full production will not be allowed to run in stock class. Older TVRs were "grandfathered" into stock classes, but not in a very reasonable way.

TVRs run in the following classes:

Stock Classes

All TVR 8 cylinder cars (including the '60s eras Griffith) and all TVR V6 cars are in B-stock. This includes the 3-litre 3000S and the 280i / Tasmin cars. They probably are not competitive in this class.

All TVR inline 4, 6s. "V-12"s (sic) and V8s are in in E stock. Of course there are no TVR V-12s in the USA (and only a few in the world) and TVR V8s are listed in two classes. This has been this way for 2 years, so it is in indication of how little the SCCA knows or cares about TVRs. Toyota MR2s and some Miatas usually are quite a bit faster than any TVR in E stock. Probably the best cars to run in E-stock are the 3.0 L "Essex V6" M and S series cars. They could be ordered with a LSD (according to the importer, Jerry Sagerman), so that should be legal. They have more power than the 2500M and better weight distribution. A 2500 M "hybrid", using the M chassis but the old vixen body weighs less but has the new (and much better chassis of the M) so it might be a good choice also.

Few modifications are allowed. Any wheel may be used that is the stock diameter, width and close to the same offset. Any tire that fits can be used as long as it has a DOT rating. Any shock absorber with 2 or less external adjustments may be used ( but ride height must be as stock), better seatbelts and a rollbar or rollcage may be added. Brakes can be any material, but rotors have to be basically stock. Since our cars are all built before 1992, we may use SS brake hoses. You may modify, delete, or add front sway bars, but can't add or modify a rear sway bar. Any service item may be used (spark plugs, etc.) and exhaust is free past the catalytic converter. That is pretty much it. There are provisions for "orphan" cars like TVRs, so read the rules.

Street Touring Classes

These classes are meant for cars that have had mostly cosmetic changes made, but are still street legal. All stock modifications are allowed and there are notably some others allowed: seats may be changed, factory trim may be removed, fenders may be flared, spoilers and wings may be added, any wheels that fit over stock brakes may be used, fancy rotors and brake ducts may be used, suspension may be modified much more, suspension and drivetrain bushings can be replaced with stiffer material, live axles can be more stiffly held in place, strut bars are allowed, oil pans may be baffled, air intake systems may be replaced, emission legal headers may be used, ECUs can be reprogrammed( yeah.... like we can do that -- as if we even have a modern ECU), and generally, modifications are allowed to make the car a better street car, but federal emission rules must still be met. Little or nothing can be done to the inside of the engine -- which for us is ominous.

A fewTVRs run in STS2, which is for 2 seater cars, but is not a mandatory class at regional events. Only cars with a displacement of 1.9 litres or less can run in STS2. This limits this option to early TVRs with small engines (such as Granturas, 1800s, etc.) This class runs on real street tires that have a tread wear rating of 140 or more and can have no more than 225 mm section width. Cars in this class are not eligible for FTDSI awards.

Street Prepared Classes
According to the SCCA:

"Street Prepared allows any carburetor or fuel injection system and any ignition system. Turbo / superchargers have to remain factory spec as well as boost control systems, except aftermarket intercoolers are allowed. Exhaust manifolds and systems are free. Emission controls are not required for competition, but no internal engine or transmission modifications are allowed beyond factory specs. Some cars are able to update/backdate components like engines, brakes, etc. (See Solo Rules for details and specs). There are no limits on wheels sizes or DOT tires and race bred springs and shocks are the norm. "

All TVRs run in A Street Prepared (ASP). They are not competitive with the modified Porsches, Corvettes, VIpers, Ferraris, Ford GTs, Loti, RX-7 Turbos and MR-2 Toyota Turbos. There is just not that much we can do with our cars to make them competitive. To put it in perspective, modified AC Cobra 289s are in BSP -- a slower class!

Internal engine modifications are not allowed in this class either. A minimum overbore is allowed and pistons can be replaced, etc. Balancing is allowed, headwork is allowed, but you must use a stock cam. So what is the reason you would redo your engine without the "killer" camshaft to make it all work? Beats me. You can use any "stock" camshaft. Sadly, the "357" Triumph TR6PI camshaft is not stock because it was never imported. With this cam any technical inspector could hear the difference from the usual smooth idle of USA spec Triumph cams.

You can update and backdate parts -- not just whole combinations. So you can run the early, high compression (8.5:1) head instead of the later 7.5:1 head. That ought to give you a few ponies!

Most of the changes allowed in the street prepared rules help the other cars in the class, but not TVRs. Lots of suspension and brake modifications are allowed, but we can't do them because we already have racing-type suspension. So the other cars get closer to the handling of our car and we can't get many more ponies to catch up with their already large advantage! Hmmmm seems fair.

Street Modified Classes
There are 2 classes here -- SM for 4-seat cars and SM2 for 2 seat cars.

This is the one place where improved TVRs might run. I'll give you the good news first:

"Engine block must be a production unit manufactured and badged the same as the original standard or optional engine for that model. "

So.... lets be clear on this. For a 2500M, you can run any TRIUMPH engine. A Stag V8 or a TR8 V8 (the old BOP aluminum V8) is OK. For a 3000S, 280i/Tasmin, 3000M, Taimar, Tuscan V6, etc. you can install a 5.0 L Ford V8 from a Mustang! Can you install a Ford V8 into a 2500M? That is the big question and there is discussion of this, but no answer. No one has tried to get that one into SM2 that I know of. I wouldn't want to put all that money into installing a V8 and find out I now run in Modified class. Would you? The question revolves around the question as to whether the 2500M and the 3000M are different models or optional engines. Were they sold as 2 different models? I won't hazard a comment here.

Now the bad news. The cars in this class may change their bodies, brakes, suspension systems, differentials, etc. to equal or surpass ours. We can improve all of this for us, but there won't be much change as we are "already there".

But to be an optimist, I think this is the best place we can run. If I was serious about running in SM2, I would take my '86 280i and install a 5-speed Mustang V8, Salisbury LSD differential, big brakes, stiff (er) springs, big sway bars, roll bar, and wide wheels and tires. It is already pretty light. I'd stiffen the frame and remove the AC. I bet it would run pretty well at the regional level. Probably win. That is, when the class is offered. It is optional. Regional events don't have to offer the class if they don't want to. They can add other SM classes if they want to to "recruit members". The SCCA is big on "recruiting members".

The minimum weight for a 2500M would be (1600lbs + (200lbs * 2.5 L displacement) =2100 lbs. I think most of our cars weight over 2100 llbs. I suspect keeping the spare tire in the car might keep us over the minimum weight. I have never seen a car weighed at an event, so I doubt it is a problem since a 2500M would be very close to the minimum if not over it a little.

The minimum weight for a 280i would be (1600lbs + (200lbs * 2.8 L displacement) = 2160 lbs. Does it make this? Who knows? I think it is pretty clear it does.

Prepared Classes
"It is the intent of these rules to allow modifications useful and necessary in the preparation of a high performance, production based non-street-driven vehicle. "

This is the first series of classes where any camshaft may be used and heads can be milled to raise the compression ratio. These cars usually have no lights, windows, etc. They are pure race cars. There is a weight minimum and a rollbar is required.

The Griffith V8 (sic) is in B Prepared, which is a supplemental class (not a national class -- no national championship and not offered at every event regionally). It gets to run in XP if there is no BP class. XP is where the MODIFIED Corvettes, Vipers, Cobras, etc run.

TVRs with an 1800 cc engine run in DP and must weight 1960 lbs. How?

All 6 cylinder TVRs run in FP and are required to weigh 0.75 * displacement. So a 2500M must weigh about 1875 lbs and a 280i must weight about 2100 lbs.

Modified Classes
Modified classes are for pure race cars. Old Formula Atlantics such as Swifts, old modified races car, single-seaters and production based major modified cars are allowed. All former street cars run in Class E and TVRs would have to weight 1700 lbs. An example of a typical modified former street car is a TR6 with a 300 HP Ford V8! I actually saw one of these run1

 

Kart Classes
I don't think TVR ever made a go-Kart, but then I wouldn't be surprised if they did.

The Philosophy of autocrossing.....

So.... why would one autocross? Especially a TVR?

Simply put, it really is a test of your driving skill. You are comparing your best time against other drivers' best times and even your driving skill against all the drivers at the event via the indexed time. But you are not actually competing against another person on the course at the same time. It is rather like qualifying at Indy -- just you, your car, the course, and the clock. Some people would say it is the purest form of autosport.

In the USA, the Sports Car Club of America (SCCA) runs the sport. There are several reasons, but the big one is that insurance is expensive and the SCCA provides it at a reasonable rate. Large limits are needed to arrange for a site and the SCCA give them in their insurance coverage. They also have a rule set that is universally used. They are probably as fair as it can be, which is not very fair. TVRs are not treated very well (as you have noticed from my comments in the earlier part of the article, I'm sure). But we are a very small part of their market. Often Corvette clubs and Miata clubs have their own events. We don't have enough TVRs to have our own event.

If I could set up the TVR rules for SCCA, I would run the following cars in the following classes:

I'd keep the others as is because it really doesn't matter. We can't prepare or modify our cars enough to keep up with the changes that will catch other cars' handling up to ours. There just isn't anything much more to do.

But there will be no changes and we are stuck where we are.

What do we do?

Well, the first thing is not to cheat. Probably you could get away with some changes to your car because no one will know. Some things that might technically be cheating have probably been done by the factory, but we can't prove it. There is no factory anymore! But there is flexibility and you should take advantage of it.

If I was preparing a TVR to autocross in stock class I would:

  1. Get good tires
  2. Get better but legal wheels
  3. Put on good, adjustable shocks set to the stock ride height.
  4. Get as much negative camber as you can by adjusting the wheels, but not more than 2 degrees
  5. Fabricate a bigger sway bar for the front with good bushings and good, reinforced mountings to the frame and A-arm.
  6. Replace all bushings with new stock bushings
  7. Install a 5 or 6 point safet;y harness
  8. Rebuild the engine so it is as strong as it can be. Tune it.
  9. Replace the exhaust system past the converter (if there is one) or the exhaust manifold with a good exhaust system.
  10. Get the best brake rotors and pads you can find that are legal.
  11. Adjust all wheel bearings and repack them
  12. Replace ALL U-joints
  13. Lubricate all suspension joints and replace any that show any wear.
  14. Get a good helmet, driving gloves and thin-soled, narrow shoes.

    Have fun with it.

For Street prepared, I would add:

For SM2, I would:

  1. Find a powerful engine from the same company and put it in. 300 hp would be enough, I would think. Probably too much. 300 HP can get you into a lot of trouble. If your car had a Ford engine, put in a 5 L Ford V8. If it had a Triumph engine, put in a 3.5 L TR8 motor. Don't take chances with this! You can argue at the protest that a 2500M is the same car as a 3000M, but there is no precedence for this, so it is a crap shoot as to whether you will prevail. And you will be protested if you win!
  2. Make new, stronger A arms.
  3. Get stronger front uprights.

Prepared and Modified:
What else can you do? The V8 will put you in Modified. Prepared allows you to modify the engine but not replace it with a different engine.

  1. Replace the transmission with a better transmission.

  2. Get a trailer and a towcar, because you won't be able to drive it on the street anymore. You're on your own from here. Some would call it a travesty to modify any TVR this much.

I have tried to make these comments appropriate to all TVRs, but they are mostly appropriate to 2500Ms and 2500s. The other TVRs can do some of these things, but some are already done (eg. electronic ignition on 280is).

Whatever you do to autocross a TVR, in my opinion it shouldn't keep you from enjoying your car and driving it every day.

Doing your best....

Most of autocrossing is closely related to what you do as a driver. There are some things you can do to improve your result and your enjoyment of an autocross. Here are some suggestions:

  1. Clean your car before the event and take out anything that might move around inside the car but you don't need. Flying objects in corners are not a good idea.
  2. Air up your tires before the event. Our cars have good suspension, so we don't need tires aired up to 40 lbs. I usually start at 32 lbs / in^2 and "read the tires" to see how much of the tread I am using during the event.
  3. Bring sunscreen and use it
  4. Get a good helmet, narrow soled shoes with thin soles, and driving gloves. To run in SCCA events your helmet must have a "Snell" rating ("M" = motorcycle is fine) from no earlier than 1995.
  5. Strap yourself in tightly.
  6. Get to the event early so you can register, clean out your car and walk the course several times.
  7. Walk the course multiple times. Walk with someone who knows the course first and then alone. Concentrate on learning the course. The novice (and some experienced) autocrossers find that knowing "where to go" is the most difficult part of autocrossing. To the inexperienced autocrosser, the first time you pull out on the course it looks like a "sea of cones". Most serious autocrossers walk the course four or more times. If you make yourself a course map that also helps.
  8. Ask for someone to ride with you if you are having trouble finding the course. But pick someone who is experienced and can help. Two lost soles don't usually find the course!
  9. Most local autocrosses have "fun runs" where you can switch cars with someone to see how their cool car compares to your cool TVR. Take advantage of that. Let one of the local "hot shoes" drive your car and comment on how it does. Drive his car to see how an experienced autocrosser makes his car work. Then, show the hot shoe your suspension. He will drool! Very few cars have a suspension as close to race car as our cars! He might even be talked into helping you adjust it to make it faster! And he will know that you aren't cheating! Ask Bill Sanford about that sometime!
  10. Most importantly, have fun. If it is not fun, you shouldn't be doing it. Don't take yourself or others too seriously. I have found that concentrating on driving the TVR makes for better runs and more fun that concentrating on winning. It takes a long time to get competitive with more experienced drivers, so enjoy what you are experiencing. Spin out a couple of times to find out what the limits are to your car. You will find they are quite high, but you can't find them until you spin. Enjoy the scenery as you spin!

Finally, while we may not be very competitive, we can really enjoy autocrossing and every once in a while surprise the other cars in our class with a good drive and a trophy!

Resources (if you have others, please submit them to me -- "farquasi@mac.com"):

SCCA rules

Good Parts

Moss Motors

The Roadster Factory

addendum:

I asked a fellow autocrosser to review this article and he was a little concerned that I am pretty negative on autocrossing TVRs. I am negative on the fairness of the SCCA rules and classifications, but I still autocross my 2500M and did autocross my 280i. Why, one might ask?

Because it is a great amount of fun! I did win in both cars for awhile. But more important, where else can you give your TVR a run like autocrossing? It is not dangerous for you nor for the car; you get to enjoy your TVR doing what it does best; you can evaluate the neat little things we all do to improve our car; and you get to hang out with other car lovers. When you show up at an autocross it doesn't matter to the other entrants that you are not going to be as competitive as a 350Z or a Honda. They probably haven't ever seen a TVR before and will enjoy your run almost as much as you do! They really ask lots of questions and enjoy talking to you about TVRs. It is one more chance to display your car and not in a static environment. I have also found that it is as much fun to drive my M to the event as to autocross. Come on -- try autocrossing. Spread the TVR name around by running some events. You will enjoy every minute of it!

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