Exige S - Rev limit

[flibberflops]

Hi,
I have just picked up my 06 Exige S and I am a bit confused about the Rev limits and I am not sure if I have a problem??

I am aware that there is a warm up period that prevents you from going over 6k

However, in my inital drives (while driving at eng temp 85c) I have noticed that the majority of the time, the "shift light" comes on at 6500rpm and the limiter cuts in at 7000rpm.
Now and again I have managed to get way over 7000rpm with no sign of a shift light, but the very next gear will max out at 7000rpm again.

I must confess I am a little confused... have i got a problem or is this normal?

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Thats not normal, however ignore the shift light - it is set conservatively low on most elise variants.

The rev limit for the exige S should be 8k with (I think) transient engine speeds up to 8.5k

7 is way way too low.

How long after 85c are you doing the runs? The engine temp reported is only the coolant temp and this heats up much faster than oil. Unofficial rule of thumb is to wait at least 10 mins after the coolant is up to temp for the oil to catch up. These cars are quite sensitive to oil visocity and it may be that it's still to cold to flow through and engage the 2nd cam properly.

[robains]

Originally Posted by flibberflops

Hi,
I have just picked up my 06 Exige S and I am a bit confused about the Rev limits and I am not sure if I have a problem??

I must confess I am a little confused... have i got a problem or is this normal?

06 Exige S?? Pretty sure Exige S started in 07, not 06. In either case, 8500 is the rev limit. I can give you a list of reasons why you want to stay 7800 rpm or less.

Rob

[Sh4rkattk]

06 Exige S exist just not in the US of A.

I also kinda disregard the shift light i just use it to tell myself that I'm in the upper range and need to pay attention to the needle. The redline is 8000 RPM with brief bursts of 8500 RPM in certain gears.

[flibberflops]

Originally Posted by ads_green

Thats not normal, however ignore the shift light - it is set conservatively low on most elise variants.

The rev limit for the exige S should be 8k with (I think) transient engine speeds up to 8.5k

7 is way way too low.

How long after 85c are you doing the runs? The engine temp reported is only the coolant temp and this heats up much faster than oil. Unofficial rule of thumb is to wait at least 10 mins after the coolant is up to temp for the oil to catch up. These cars are quite sensitive to oil visocity and it may be that it's still to cold to flow through and engage the 2nd cam properly.

Cheers for the replies. I do ignore the shift light, the problem is that the limiter seems to be cutting in 500rpm after the shift light at 6500rpm.

I guess there must be a problem, but its kinda wierd because its a higher rev limit than the 6000k cold limit... and now and again it does let me do the full 8000 limit... but rarely.
I guess its straight back to Lotus for investigation.

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surprised it hasn't kicked out any failure codes - be worth hooking up to the obd port to see whats up.

[Sh4rkattk]

Sounds like a problem. I would say check the oil filters for the cam switch but that won't cause a lower rev limit, your cam just wouldn't switch.

Could be ECU related, cam sensor maybe, best bet would to take it to lotus.

Are you in Europe to help explain the 06 S.

[flibberflops]

Yeah, in the Uk. Only picked it up yesterday... and its had a full service in the last week, so I am guessing it musy be a Cam switch issue.

[robains]

I didn't know UK had 06 S, learn something new. Cam switching (good or bad) will not change your rev limiter light activation RPM (only warmup <160F, but since you're at 185F not the problem).

Could you describe what you believe "hitting the rev limiter" is -- your description could help us determine if you're really describing the rev limiter or something else.

What is your speed at the time you hit the rev limiter?

Rob

[Hello Kitty]

hmmm 7000 rpm...
You need to turn traction control off.
TC sounds exactly like hitting the rev limiter.

TC is "on" by default.

[flibberflops]

The speed limit (when this happenes) is varible because this happens in all gears.

Also I should also say 7000rpm as an approximation because it is hard to say exactly because you can appriciate that at the time I am doing some major speed and its hard to see exactly when you are accelerating hard and suddenly hit a invisable wall. At a guess, I think its happening just short of 7000rpm... more like 6700-6800 rpm.

However, the important bit to note is that now and again (vary rarely) I get the full 7000rpm+ revs.

I do have traction on... but I am unaware of anything that stops you going higher than 7000rpm with traction control... i am certainly getting no dash lights to say traction is cutting in???

[Hello Kitty]

Ok, now I KNOW its your traction control.

Whenever the computer detects as much as a inch of wheelspin, it will cut the spark to the engine for a second. It sounds exactly like the rev limiter.

Turn off TC, and you will not hear that flubbering sound again.

Seriously turn it off.

I turn TC off as soon as i start the car... everytime.


BTW, you dont get any dash indicators as to when TC does its thing.
You just get a dash light when TC is turned OFF.
(icon of peeling out car means TC is OFF)

[robains]

If this is happening in ALL gears I doubt it's TC, unless you have a 800 HP Lotus?

One possibility is that you have a wheel speed sensor going bad that could be artificially inducing TC -- but you can validate by turning TC off and see if you hit 8500 rpm rev limiter. 3rd, and 4th should give you plenty of time to look at the Tach (again unless of course you have 800 HP) -- 4th is good to about 114-115 mph.

Rob

[Mr. Know]

For the sake of troubleshooting, check your ECU fuses as well. I seem to remember something about a blown fuse causing similar symptoms.

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Worth trying with TC disabled - I don't think it's that but certinaly good to check.

Dodgy wheel sensor is possible although I think unlikely - the abs system is quite hot on picking this up. However you can force it to be disabled by unplugging one or both front wheel speed sensors. This will also disable the ABS so be careful if you lean on it now and then. As there's no front wheel speed input TC won't work as it requires both.

Does it happen under all engine loads or is it only under heavy or WOT?

One possibility is that the engine is picking up something like pinking or detonation (all possible with an FI setup) are retarding the igntion so much that it's having the effect of appearing like the limiter.

IIRC On the exige S the cam switch is much lower at around 4500 so I take it back about being the oil for the cam change as stock NA it changes at 6200.

Worth pulling the plugs out a checking their condition or replacing as is checking any OBD codes stored that haven't triped the engine failure light.

[apk919]

Originally Posted by flibberflops

I do have traction on... but I am unaware of anything that stops you going higher than 7000rpm with traction control... i am certainly getting no dash lights to say traction is cutting in???

When the TC kicks in, the traction control icon lights up on the dash (at least it does on my '07 Exige S). If that light isn't coming on, your problem is not traction control.

[flibberflops]

Thanx for all the suggestions guys, however I took it out the weekend (twice) to test it with TC switched off....

However, I didn't get that far because the problem has totally gone? WTF???

I was driving away from the city to find some quite roads for testing (with TC still on) and I noticed it wasn't doing it any more!
I drove it a lot over the weekend and the problem never happened once!

Totally confused now?

[robains]

did you wash the car or have it washed before you tested on the weekend?

[flibberflops]

Nope... but it was driven in light rain just before the weekend.

Why, what are you thinking?

[robains]

Then I'll stick to my guns and say wheel speed sensor(s). Easy to check/clean contacts yourself - look for water in the connectors.

Rob.