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Q1. I have a big exhaust, will I get overboost?

A1: If you get boost creep with a standard PROM a mountain chip probably won't fix it. You might get lucky if your boost peaks between the standard chip limit (0.92bar) and the mountain chip limit (usually 0.98bar) but the odds aren't in your favour. If you don't get appreciable boost creep (maybe you're lucky or you've ported your wastegate or whatever) then the chips shouldn't cause problems. Remember all large exhausts seem to behave differently and I can't test the chips on a car with a large bore exhaust myself - my car's have stock exhaust systems - so I can't make guarantees. I will do my best to ensure that any overboost problem caused by the chip is eliminated.

Q2: How do I know if I have a 9929 or a 9930?

A2: Look for some ways to tell.

Q3: I have a catalyst equipped car, will I get 0.9bar, if not should I get a Kili or how can improve my maximum boost?

A3: If you have a stock exhaust system complete with catalysts then you probably won't achieve 0.9bar for much, or sometimes any, of the rev range. If you want to achieve the full boost you can replace the exhaust system with a larger bore item (catalyst equipped ones won't creep either) or some people knock out either the pre-cat or main cat (naturally I can't condone such behaviour). If you stick with a standard system then a Kili wouldn't deliver much less power than the Everest but having the latter won't do any harm and would maximise what you have available.

Q4: What if doesn't work for me or I don't like it:

A4: I will refund on return of any undamaged item returned within 4 weeks. I'll consider sympathetically any request for a refund after this period too.

Q5: Why not do the V5 or Elysium on a single program chip?

A5: The chips gain power by trimming margins. The boost of the everest is on the limit of the fuel delivery system's capability at high revs (the Elysium is at the limit across much of the rev range), the safety boost limit is pushed up and above all, with the V5, the mixture at high boost is optimised for power not engine protection. All this is fine is everything is working well, however, if an injector is sticky or the fuel pressure gets low or the timing goes out or there's a CAS problem then the consequences are that much more likely to be serious without the extra fuel to keep the mixture from running lean and to cool the intake charge. If the engine isn't running well its easy to run a richer map with a switcher. If a one program chip is installed then the only way is to uninstall the chip which, while not complicated, does require the removal of the ECU. If someone installs a V5 in a car with an FCD present then it would almost certainly damage the engine. Frankly I have reservations about selling it to people of unknown technical competence at all...

Q6: I've e.mailed & PM'd you 4536 times in the last week and you haven't replied.... or I ordered a chip three days ago and haven't heard anything etc

A6: This is a sideline - it doesn't pay the bills. It is primarily a hobby but since I'm registered for VAT the tax man would take a dim view if I didn't put it through the books. I aim to ship within a week sometimes it will be two. If it's likely to be more I'll let you know and issue a refund if desired

Why not use a cheap MBC (with optional FCD) or an Expensive BBR kit (which is an MBC+FCD)?

A7: An MBC puts a fixed leak in the air line to the wastegate this increases the pressure required to open the wastegate and gives higher boost as a result. Its primitive but it works with a few caveats:
  • With an MBC the leak is always on so the engine will be exposed to high boost even when the engine is cold or faults are detected.
  • An MBC cannot react to changes in atmospheric pressure - maximum absolute pressure will vary by 0.1bar depending on the weather. This can mean overboost fuel cut some days but not others.
  • With an MBC the knock control strategy in the ECU functions only partially, spark retardation remains but boost reduction (via the BCFV) is disabled.
  • The boost attained varies with RPM (due to changes in turbo & wastegate efficiency with RPM) so the boost will vary over the rev range, the peak boost will occur at around 4500RPM.
  • An FCD removes all the protection against uncontrolled boost caused by a stuck wastegate.
  • An FCD fools ECU into believing the boost is lower than it actually is and all table lookups that use manifold pressure (mixture & spark advance included) are compromised as a result - for example the engine will run progressively leaner and more advanced than programmed in the ECU above the clipping threshold (generally around 0.75-0.8bar). This is possibly good for power but potentially bad for engine life. Its a good thing the ECU also includes knock control by timing retardation!

Requirements for a Successful Installation


Disclaimer - must be accepted to purchase

This modification is intended for track day use to increase the maximum boost and optimise the fuel mixture of the Lotus Elan. Installation and use are at your own risk. It is the owners responsibility to ensure that this modification meets any local legal requirements. Any modification that increases power makes mechanical failures more likely as engine/drivetrain stresses increase. I accept no responsibility for any failures caused by this upgrade.

If you do not accept this disclaimer then do not purchase or install the upgrade.


The following common modifications will affect the functionality of the chip:

1. Fuel Cut Defenser (FCD)

The Elan must not have an FCD installed (this includes the BBR upgrade). The FCD is a device that prevents fuel cut on overboost. If your Elan has a performance exhaust from Paul Matty Sportscars (they often insist on one being fitted to combat boost creep) or it has another performance modification that allows it to boost beyond 0.9bar then there is a good chance one is present. DO NOT FIT IF YOU ARE IN ANY DOUBT – CONSULT SOMEONE WHO KNOWS WHAT TO LOOK FOR.

2. Manual Boost Controller (MBC)

Any MBC must be removed. It is usually a bleed valve in the pipe between the wastegate capsule and the BCFV. Sometimes one is installed in place of the BCFV. Either way the system should be restored to standard configuration BEFORE fitting the new chip.

Figure 1 BCFV plumbing
3. Sports exhaust fitted (greater than 2 inch diameter)

If you have a large bore exhaust fitted (>2" bore) and suffer with boost creep this upgrade will not cure it. However, if an MBC was employed then its removal may have corrected the issue. It is advisable to check the hoses to the BCFV for leaks thoroughly and to ensure unions are fully secured. Remember this line is pressurised under boost so the seals must be good. Test-drive the car to see if the creep has been resolved before fitting the chip. If boost increases beyond 0.95 bar then fuel cut will still occur with the chip and you should consider porting the wastegate, putting a constriction in the exhaust and whether its worthwhile installing the chip.

4. Blow-Off Valve

If a blow valve is fitted with a spring that vents with a boost pressure less than the maximum target level then this effectively limits the boost to its cracking point and you will not achieve the rated boost for the chip. Should this occur I would advise it is rectified quickly (preferably before chip installation) as the turbo will spin very rapidly in this state due to the low resistance in the intake and the high BCFV duty cycle applied by the ECU in an attempt to meet the target boost.

5. SuperChip

I have seen a couple of PROM dumps from SuperChips installations (which was subsequently successfully re-chipped with an Everest) - the modifications were to the MEMCAL alone and therefore presented no problem with this upgrade. Its possible other, different, installations exist so if you see anything inside the ECM that looks like a previous 'chipping' (compare the MEMCAL installation with the pictures in the instructions) let me know.

6. Upgraded Turbo

In principle this upgrade should work with a new turbo so long as the BCFV plumbing is laid out as in figure 1 and the target boost is no more than 0.9bar or so. It is possible some further table changes will be required. Contact me with details.

Engine condition

If you have a problem – this will probably make it worse. Any misfire will be worse and if your cylinder head gasket is on the way out the extra boost will finish it off. Only install if the car is running well.

  • Properly set timing is critical to realising the power gains
  • The higher pressure will exacerbate any ignition problems (coilpack/HT leads/plugs) and lead to misfiring
  • Because the pressure is increased in the induction system leaks can appear and mess up boost control - poorly secured pipes have been blown clean off!
  • The increased torque can take out your exhaust if its near the end of its life. Thank Lotus for putting a rigid exhaust on a mobile engine guaranteeing fatigue failures of the mounting bracket under the engine (gives an annoying rattle at around 4000RPM) and even the exhaust or frontpipe.


Please e.mail me.
A refund (excepting p&p) will be given if the upgrade is returned undamaged, for any reason, within a month of receipt.

Performance data

Quite a few dyno runs have been performed on Elans with and without chips. None of the data here was acquired by me or even in my presence.

V3 & V4 Chips

The V3 & V4 chips increase power simply through increasing boost. They also improve boost delivery by modifying the parameters of the boost control routine in the ECU. The graph shows power curves from various Elans, two each of standard configuration, Kilimanjaro chip fitted and Everest chip fitted. The chip version varies, V3.x and V4.x are represented. All the data was supplied by members of the LotusElanCentral forum.

std-Kili-Ev power


V5 Chip

The V5 was developed by created 16 power enrichment maps that varied smoothly between the stock Elan table and a considerably leaner (10.2:1 compared to 12.3:1 at the richest point) candidate table.

Candidate mixture maps

The test runs were performed on a dyno with exhaust gas analysis and ElanScan logging so that any knock could be detected. Not all the maps were run, the plan was to home on the best power version without knock.

Results are below (the curves were smoothed to reduce the influence of random variations and assist the analysis).

V5 candidate power runs

The V4.2 (a high boost chip with no fuelling modifications) was used as a control. Its power curve was subtracted from the candidate maps to give a power gain graph:

Power increase graph

The next graph shows the trend between power gain and the change in a/f ratio

Effect of a/f increase on power

Dyno data is intrinsically pretty variable, the above data was acquired in one session with one car but the same map can still produce quite different results on different runs (see the two points for map 8). Intake temps, boost, etc were similar in each case. The value in producing data like this is that trends can be spotted in spite of the noisy data.

Map 8 was selected as the default map for the V5, it offers the best power boost with no measured knock.

Technical Background

Boost control

The underlying passive boost control system

The Elan has a simple underlying system to control boost that is common to most turbo applications. The turbo is simply a pair of wheels connected by a shaft, the first wheel is driven by exhaust gases from the engine and this rotates the second wheel which draws air in from the intake and pressurises it. The pressure generated is limited by a valve, known as the wastegate,  which is opened when the boost pressure exceeds a threshold and diverts the exhaust flow so that it bypasses the drive wheel. This system is entirely passive - it is isimple plumbing - and the engine management system has no involvement in it. In the Elan the wastegate is designed to open at a boost of 0.4 bar.


Active boost Control

The engine management system can't directly influence boost below 0.4 bar, however, a system is installed which allows boost to be actively controlled to higher levels. The wastegate is opened by air pressure fed directly from the turbo's output. In the Elan a solenoid valve, known as the 'boost control frequency valve' (BCFV), is present in the pipe leading to the wastegate capsule and when this valve is open pressurised air escapes from the pipe and the wastegate doesn't 'see' the full boost pressure and so does not open until higher boost. The magnitude of the leak has to be controlled closely to allow good boost control. The solenoid valve is a simple open/shut type, however, a method known as 'pulse width modulation' (PWM) allows the ECU to give the BCFV a controllable opening by simply operating it at a high frequency and controlling the proportion of the time it is open - the duty cycle. If the valve is shut then the duty cycle is 0% if it's open half the time it's 50%.

The engine control unit (ECU) controls the boost by executing the following loop several times a second:

    1. If the throttle angle & engine speed exceed the required threshold active (closed loop) boost control mode is entered
    2. The boost target is looked up from tables, the lookup variables being throttle angle and engine speed
    3. If the current boost is below the target then the wastegate duty cycle is increased, if above the duty cycle is reduced
    4. repeat until active boost control conditions not satisfied

The system is not sophisticated but it does have many variables that can be optimised for improved boost control. The biggest complicating factor is that large bore exhausts change the relationship between boost and wastegate duty cycle in an unpredictable way and this forces a more conservative boost strategy than might be possible if all cars were stock!

Boost Limit

The Elan has a boost limit and the engine management will cut the engine to protect it if the boost exceeds it. The limit is present because the fuel system of the stock Elan can only deliver enough fuel to reach the required enriched air fuel ratio up to 0.9 bar at high rpm and so the limit was set to 0.92 bar. In order to provide a control margin the cut point is elevated to between 0.96 and 1.0 bar in the mountain chips.

Fuel Enrichment

At high boost the engine mixture is made richer in order to cool the charge and inhibit knock. The level of enrichment in the standard Elan is very high. This provides a useful safety margin that has probably saved more than one engine from detonation when low tech boost upgrades (particularly those which modify the output from the manifold pressure sensor to prevent fuel cut) were used. However, in the V5 chip the fuel enrichment has been optimised to give optimum power without knock. This has improved the power output but reduced the safety margin....


The ECU solution leaves all the safety features enabled:

  • Boost is limited to 0.5bar when:
    • the coolant temperature is below 50°C
    • any fault code is set
  • The boost is progressively reduced if knock retardation exceeds 5°