Lotus 'Ice Mode' Explanation

The Lotus have suffered from a phenomena under braking that feels like you've lost your brakes - this is something we mentioned in our recent blog entry with our Switchblade.  I found an explanation for this issue from a noted Lotus Engineer at the UK factory.

The symptoms being described are a result of the Electronic Brake Distribution (EBD) system operating. This system is also referred to as Dynamic Rear Proportioning (DRP) and is, as the name implies an electronic system which, through the ABS control valve block restricts the line pressure to the rear brakes automatically to a pre-programmed algorithm. You can consider it as an electronically controlled proportioning valve which measures parameters like the rate of deceleration and rate of pedal application and uses this data to anticipate a rear wheel lock-up and then reduces the braking effort at the rear wheels as necessary. If the ABS system is left to do this, it can only react to a wheel as it starts to lock and therefore the car can already start to spin before the ABS can start to work. In extreme circumstances, if the driver brakes very suddenly the EBD system can lock off the pressure to the rear wheels completely; what pressure was at the rear brakes as the EBD system engaged remains there and the rear brakes are still working as a result, but further increases in pedal effort will not increase the braking at the rear of the car because the pressure to the rear brakes cannot increase. When this happens the brake pedal goes hard, as it is now pushing against the front callipers and a closed valve only, instead of against the front and rear callipers. The rear callipers are single piston and therefore quite flexible, so they are a major factor in making the brake pedal feel 'soft'. When the valve closes, the brake pedal pressure no longer flexes the rear callipers, hence the increase in pedal hardness. The front brakes are still working just as well as before the valve closed and will give more braking if the pedal effort is increased, while with the rear brakes working as hard as they can the braking is NOT affected. The problem is the driver feels like braking is reduced (even though it is not) because of the change in pedal feel. If the driver continues to push hard on the pedal, the car will continue to slow as fast as it possibly can in the circumstances. If he increases the pedal effort the front braking effort will increase and the rear effort will remain where it was. If he was to back off the pedal for a fraction of a second, the valve will reopen and the rear brakes will operate as normal again, with the pedal feel going back to normal.

In the case of releasing and re-engaging the pedal the car should not be able to slow any faster than it was with the system engaged unless either 1: the driver triggered the system in the first place by stamping on the pedal too fast or 2: the system triggered because a rear wheel was unloaded when the brakes were applied and would have locked up but is now fully loaded once again and able to sustain a greater braking torque. If the rate of deceleration does improve when the pedal is reapplied then it is telling the driver that he is over braking either in terms of the ultimate ability of the brakes (cause 1 above) or the track condition (cause 2 above) and needs to adjust his driving style to suit. If the system were not fitted or disabled and he continued to drive that way he would be in danger of spinning when applying the brakes. 

The suggestion that the system is running out of vacuum is just plain wrong. The system carries an internal reservoir of vacuum sufficient for three full brake applications. As with every servo system ever fitted to a car there is a one way valve which prevents the vacuum being lost when the car is on boost. The only way this reserve can be depleted is if the driver is maintaining boost while applying full brakes, i.e.: left foot braking very badly. In this instance I would argue that depleting the vacuum is probably a good thing as it should provide him with a warning that he is doing something awful to the car and it may reduce the speed of impact when he finally hits something as the brakes fade to nothing!! In normal use the throttle is closed when the brakes are applied, there is therefore no boost and the vacuum is automatically replenished as it is used."

So there it is, 'Ice Mode' is an inherent issue that can be addressed with some old school brake pedal pumping.  I think the pedal feel, when it goes 'hard', tends to be the most disconcerting as it happens when you are approaching the corner at high speed.  Many racers have disconnected the ABS system in an effort to reduce this issue and frankly it is a good solution for advanced drivers.  

We think that the brakes on the Lotus are still awesome even though they lack the firm feel that you get from other sports cars like a 911.  The flexible single piston rear caliper appears to be a key reason for the softer pedal - but we'll take it as we go 2-3 cars deeper into every corner than those massively powered GT3, ZO6 and M3s...

Another solution is to upgrade the front brakes to our 308BBK  or 308vBBK and move your front calipers to the rear with our FCRbracket.  We disconnect the ABS with this set-up.  One nice feature is that you can keep the stock rear caliper so you can retain your handbrake.  For about $2k you can effectively have a complete BBK kit for your Lotus.  We ran this successfully on our Art Car with great results including two track records in Lotus Cup.

High Mileage Lotus - Benefits of 60pt Prep

Recently we serviced a repeat client who puts a ton of miles on his '05 Elise.  With 94,000 miles, this may be the highest mileage Elise in North America.  It is definitely the highest mileage car we have seen.  James first brought his Elise to us in Jan 2010 with 56,000 miles on the odometer.  At that time we conducted our 60pt Prep on the car.  This preparation checks over 60 of the critical areas, of a Lotus, that tend to loosen up.  Our service removes the fasteners, threadlocks them, torques them to spec and then paint markers each one.  You can find our 60pt Checklist on our Tech Tips page: HERE  Feel free to download this and use it to prep your car.

The picture below shows the old paint markers that we had put on James' car at the 56k service.  Even after 40k additional miles, you can still see them.  This technique allows you to visually inspect your car to quickly verify that your critical fasteners are still torqued correctly.  If you see that a paint line has shifted, this is a good indication that you need to retorque.

Once we inspected the car, we noticed that most of the fasteners had not moved.  We still removed each fasterner, reapplied threadlock, then cleaned off the old markers and repainted the joints.  These paint markers are readily available at auto parts or hobby stores.

One of the issues that we found during this inspection was the rear bushes had moved and the wishbones were making contact with the subframe.  The picture below shows what we found.  

Typically we see this on track cars but even high mileage street cars that are driven with some enthusiasm can exhibit this problem.  Luckily we have a couple of solutions that can help:  SL Bushes and the MONOballs or Nitron Bearings for the track/race focused cars.  We have a previous blog entry about this issue: HERE

We are big believers in the fact that these Toyota powered Lotus can be reliable cars.  The two basic requirements are that you:

1. Keep the fluids & filters fresh
2. Keep the critical fasteners torqued correctly

If you follow these basic rules you can run your Lotus for years with confidence and a grin on your face.

Switchblade Track test at SMMR

I took our Exige S to the track to do some initial testing.  We have several items on the car that needed to be evaluated, including the new clutch and suspension.  It was the first time in years for me to drive an Exige S on track and it was interesting difference compared to the Elises that we have had the last few years.  The car performed well and had some good points and some bad ones.  I ran her on SMMR's 1.5 mile configuration.

The Exige was very fast as we installed our BLADE275 kit on it.  This car accelerates like a scalded cat!  The auxiliary ducting kept the proICduct well fed with air so it did not feel as heat soaked as with the stock set-up.  The ambient temps were well into the mid to high 90s during my testing.  Water temps stayed below 203degF.

 The new clutch felt great.  During the initial break-in the car was a bit touchy when you launched it from a stop on the street in 1st gear.  I'm embarrassed to admit that I stalled her a couple of times!  The clutch now has approx 500 street miles and feels fine.  The pedal effort is slightly higher than stock but the power rating is much higher so I think it will be a very good option for clients with more power and who run on track.

The suspension is very soft and glides over the bumps very well.  It had great grip.  The car swayed much more than our last couple of Elises thanks to these softer spring rates but you could also feel the weight up high on the Exige.  The IC coupled with the roof, hatch/wing make for a car that feels more 'top heavy' than the Elise.  You really notice it on the track.  The 'inch down' ETHOS wheels and larger sidewall Toyo RA1s also contributed to the compliance and slightly slower turn-in.  The car was very fun and easy to place.  We still have the stock seats and no harnesses and I moved around quite a bit as a result.  We'll add some harnesses soon.

The single biggest negative was the 'ice-mode' issue that I was experiencing on a couple of turns.  This is a known issue with the ABS system on the Lotus.  I ran with the ABS on but many racers defeat it as it can cause this disconcerting feel of having no brakes.  Truth is, the ABS system thinks you are slipping so kills any additional rear brake pressure but your front brakes are still working.  If you get off the pedal and immediately back on, it corrects itself.  Of course that is never fun when your corner is quickly approaching!  We were running stock pads with our ULTRAdiscs so the initial bite was also a bit lacking thanks to the pads.  Different pads will make a huge difference.  We were testing a new brake fluid and it appeared to work fine as it is hard to boil fresh fluid in a Lotus.

I also had some shifting problems.  I think our cable adjustments need to be looked at but I was mostly having some shifting issues on the track.  Again it is well known that the 2ZZGE moves quite a bit with track use - especially with the addition of an IC on top.  We installed our sportINSERTS to help this issue.  I need to look closer at our adjustments to see if that was the cause or if we need to run stiffer mounts.

I drove the car to the track to see how comfortable it would be.  The TRACKpipe sounded great on track but was a little bit intrusive while cruising along the freeway.  The Exige is a louder car than an Elise.  Mufflers that do not drone, like the TRACKpipe, in an Elise, will be louder in an Exige.  I think the rear fastback clam of an Exige creates a bit of an echo chamber that causes it to be louder.

The day I arrived, a SMMR member took delivery of his new Spec:Race Atom.  He will be running it in our Winter Race Series.  Barry got one session in the car and we made a quick video of his initial impressions.

Switchblade modifications & weigh-in

The boys have been busy adding and deleting items from our Exige S.  The car has lost a paltry 7lbs but has gained quite a few performance parts that have made the car distinctly better than stock.  It now handles better, is faster and sounds better.  We have also added a couple of new items that we are testing including a new clutch.

Our new MRbearings were fitted to confirm that our production parts were correct.  Frankly the NVH penalty has been a non-issue, I was expecting more noise but it seems similar to stock.  This modification is truly a hardcore solution for track focused cars but we needed to ensure the fit so chose to install them on Switchblade.  This product is now available on our website and sure to be a hit with the racers.

We also installed our BLADE275 which features our proICduct.  This kit transform the power of the car to 275hp.  The acceleration and added supercharger whine is intoxicating.  Our experience has shown that this is at the threshhold of power that is acceptable for track use.  We will avoid slicks on this car to keep the syncros in our tranny happy.  Our gPAN3 was also added to protect Switchblade from oil starvation that is sure to occur on track.

We are testing a new clutch.  The pedal pressure is slightly higher than stock but it can hold much more power.  It is getting broken in now and feels like a great solution.  Of course, I managed to stall the car a couple of times as it was breaking in....hmm, you'd think after 30 years of driving manual transmission cars I could avoid these red-face situations.  ;^)

The handling of the car is really great.  I've been playing with the shock settings and landed on a setting that seems to work well on the street.  I will run the car soon at Spring Mountain.  The combination of supersoft springs, 15"/16" wheels has resulted in a car that has great grip and compliance in the bumpy roads yet the control delivered is excellent.  We are running shock settings that are fairly firm - track level settings - but the car feels great.  The added tire sidewall gives us some more 'spring' for added compliance.  This set-up feels like the right solution for folks dealing with rough roads.  We'll continue our testing and get our man, Dave T in the car for additional professional feedback.

We added one cosmetic mod - a powdercoated gas cap.  Black just looks so right on these cars...though it is missing in the pic below...

Lotus Ball Joint Unconstructed

The Lotus variants use a standard automotive sealed ball joint to connect each of the wishbones to the uprights.  Ball joints are a great solution as they allow movement in different directions - the suspension can go up/down and the joint can go side to side to allow the wheels to be steered.  We cut one open to see the internals(see above).  The Lotus ball joint features a ball stud that moves along a plastic internal 'bearing'.   A rubber boot keeps the lubrication internal so the ball and bearing don't freeze.  This type of design is preferred on street cars since they have good performance and are well protected from the elements which results in a long life.   

We've developed a spherical bearing conversion kit we call the MRbearings.  We tested it last year in our race Elise (Art Car) and introduced on our Blog: HERE.  This solution is in production now and will soon be released.  We like the performance it delivers but also like the fact that we don't need to use a ball joint separator to disconnect the uprights or run the risk of tearing the rubber boots on the ball joints.  This is a track focused solution that won't likely have the street life of a standard ball joint.  But you already knew that...

SWITCHBLADE Mods: Suspension, Wheels, Shifter & Brakes

We have made a few changes to the Switchblade.  Since our last blog entry we have updated suspension, shifter and brakes.  Some of the items we've installed are new parts we are testing to determine if they are fit for use.  We will reveal them in full once the testing is complete.

 The stock shifter on the Elise/Exige is one of the areas that is a disappointment.  The steering feel is amazing, the handling is great, the exhaust/engine note can be made better, the brakes are OK but the sloppy shifter action definitely lets many people down.  We have been selling various shifter improvements for years that have helped make the feel much better.  We installed a Bollock and shifter cables on our car to improve it.  It has made a nice imporvement - in fact a client with the same car drove our car and was instantly smitten.  He had us install the same parts and is much happier with his car.

 The stock brakes are OK but you can save significant unsprung weight by installing our ULTRAdiscs.  We chose our limited edition Oro series with the gold hats.  These save 10lbs.  We are also testing a new brake fluid that claims to be of higher quality and performance as well.  Stock pads and calipers remain for now.

We installed a set of the ETHOS wheels in the 'inch-down' sizes for more weight savings.  We choose to put on the Toyo RA1s so we would have a street tire that still delivers track capability.  We are keeping this car reasonable on the street and resisting the temptation to build another track monster!  I think these wheel/tire combo is perfect for any client living with rough roads or tracks.  The aesthetics of a smaller wheel can be controversial but we are used to introducing looks that most people don't like at first...I do believe that 'form should follow function'.  A picture of an Elise is posted below with the same wheel/tire combo for your review.

Nitron Singles with softer spring rates than our 'Soft' rates were installed as well.  The canyon roads in CA can be quite bumpy.  This combination along with the ETHOS has delivered a magic carpet ride.  Switchblade is very comfortable yet maintains the tossable and responsive handling that Lotus are known for.  Ride height was kept at a reasonable 130/135mm to ensure good street clearance.  We yanked out the  front shims and some from the rear.  We landed on -1.5/-2 deg of camber front/rear.  Toe was set at zero on the front and 3mm total toe in at the rear.

We had sent our our gas cap to be powdercoated black.  A new clutch is coming from a partner of our for testing.  It features a stronger pressure plate and street friendly clutch effort.  We thing it might be the perfect solution for most owners.  This will go in along with a lighter flywheel from Fidanza.  A BLADE275 will be installed soon.  We just installed a kit on a clients car and it is fast!  Switchblade needs to get some similar TLC...the list of items to install is still a mile long...

First Switchblade Mod: TRACKpipe & The Eliminator V3

The Switchblade came to us stock so one of our first modifications was to reduce weight and improve the sound.  The stock Exige 'S' muffler weighs approximately 32lbs.  We swapped this out with our race-proven TRACKpipe and saved just over 16lbs.  This muffler has a tip that exits out above the diffuser for improved aerodynamics.

We also added The Eliminator V3 which now comes in a black powdercoated finish.  This product helps shed heat that builds up in the rear and reduced an additional 4.5lbs from the back of the car.  We introduced this 'naked rear' to the US market many year ago and took some initial lumps from clients who did not like the appearance.  Over time, the community has come to embrace the benefits of the naked rear and have come to accept this look as something that keeps with the old adage of 'form following function'.

The car now sounds like a proper sportscar with additional supercharger whine adding just the right sound!  Savings 20lbs is a great start with more to come soon....

We also said good bye to a sweet ole friend, our Art Car.  She has left to a good home down in SanDiego.  Jack is an excellent driver who will be able to extract every bit of performance from her.

Introducing our latest project Lotus Exige S: "Switchblade"

This past weekend we took delivery of beautiful '07 Exige S220 with 20k miles on the clock.  Our game plan with this Exige is to develop a very cool, street-friendly Lotus that is also safe to run on track.  We will reduce weight with various products but not make any drastic modifications.  One goal with this build is that all changes need to be reversible to stock.  We know this will limit the overall performance potential of the car but we've proven our ability to build fast track cars so we will display some restraint with this build.

We picked her up from Abe@Newport European.  Abe has been active in the Lotus community for many years and is a guy I know and trust - plus he loves these Lotus.  The previous owner of this car took excellent care of the car as it was in like-new condition.  The only modification he had made was adding one of our darthHOLDER to the car - even though it came with the nifty stock cup holder.  The car has had all the recent service/recall updates.  The front lip has the typical scrapes underneath.

I drove her home on the CA freeways and have been driving her for a few days to calibrate myself - before we start our mods.  The car is fun and definitely not as insulated or comfortable as the Evora.  The acceleration is good.  The rear visibility is non-existent as the intercooler blocks your view - though the previous owner had removed the rear view mirror.  Some wind noise comes through the side glass and the roof.  The sport suspension/forged wheels/A048 tires deliver plenty of fun handling on smooth roads but can feel a bit stiff in the bumps.  The freeways are notorious in LA for expansion joints that cause a very uncomfortable ride in stiff cars - especially those equipped with the Lotus Sport Suspension.  The car has an iPod connection so I enjoyed some of my favorite tunes.

Some of the lightening areas will include wheels, brakes, street-oriented uprights, roof, exhaust and seats.  We decided to weigh her to see what we are starting with.  2072 lbs full of fluids was the result.  We will weigh her periodically to see our progression.  The car will get a BLADE package for added power.  We think that 275hp should not annihilate the trans on track - especially if we forgo super sticky slicks and focus on smooth/slow shifts.  Restraint is key...

I really love the color of the car and am scheming some way to make it look a bit more distinctive but not too racy or aggressive.  I have always tried to innovate technically and aesthetically - this car will have something cool about it visually.  Here are some inspirations:

 

The Exige still garners more attention than you might imagine.  Lotus got the formula right with the Elise & variants.  I drove a track prepped Cayman yesterday and got out after a couple of laps.  It felt like a boat  with slow responses.  The Cayman was not as engaging as I come to expect from my track cars.  Even though these Lotus have been available here since 2004 (yes almost ten years!), the performance, size and shape continue to put smiles on the faces of the many - including me.

Exige 'S Build Coming Soon

We are now looking for a '07 Exige S to build an awesome street friendly yet track ready Lotus.  We had previously focused on hardcore track with our last project the Art Car - which still holds the Lotus track record at Buttonwillow.  The time is right for us to build a car that we can take a friend in without getting a headache from the NVH!  More details of the build will come and of course we will be blogging about it here.  Expect this car to use weight savings measures and performance enhancements that don't take away from street useability and comfort - if you really believe a Lotus and comfort can be used in the same sentence...;^)