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Discussion Starter #1
So, what's the max boost that you are running with your Exige S? 3.1" pulley? 3.0" pulley? High flow intercooler? How do your timing curves look? (A good indicator of knock).

This thread won't be complete without tales of Ronin... doesn't he have a 0.125" pulley? LOL

I'll meet you back here in a couple of weeks, let's hear who is pushing the envelope.

:popcorn:
 

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I haven't even opened the letter yet, much less start doing anything with the envelope itself (har). Interested in what folks are doing out there too... as far as I can tell, from my reading all the different topics on this subject, is that there is a line to cross:

Either you tune the ECU for as many of the "usual" mods (exhaust, airbox, headers, de-cat, etc) and go for tuning in the motor as-is, or you take that next step to include the above plus s/c pulleys, injectors, and then the next step is internals.

But the jump from that first level of squeezing on the stock motor for what seems to be at most 10-20hp and move on to the s/c pulley and injector mods and it seems like nothing is reliable/safe without also leaping into some sort of liquid-intercooling.

That's why we're all so interested in what kind of performance we'll see out of your RLS CUP-style intercooler. You may be offering that intermediate step some of us want without having to pull all the panels off and install a chargecooler to begin taking advantage of real mods in a reliable and driveable fashion (eg. currently s/c pulley + injectors + usual mods + chargecooler + gotham tune = fun times...but that chargecooler part is $$$$!).

At the moment it seems like anything less, due to our air cooling constraints, is just kind of playing around with a few hp. And this is where I think mant people are stuck, and why there may turn out to be very few posts in this thread.

Big jump in price too..to go to that next level.

Maybe the RLS intercooler will allow more folks to take those "next steps" for the pulley, injectors, and a worthwhile tune, without the cost and labor of liquid intercooling.




:popcorn:
 

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Don't the Exige S's run MP45 units? Other than the Bemani kit running the M90, I think the rest of the kits out there are running the MP62 Eaton units...
 

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Don't the Exige S's run MP45 units? Other than the Bemani kit running the M90, I think the rest of the kits out there are running the MP62 Eaton units...
Exige S's (at least the 07's) run the MP62.
 

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MP62 on 07 Exige S(220)
MP45 on 08 Exige S220
MP62 on 08 Exige S240
MP45 on 08 Elise SC

Basically the non-intercooled cars use the MP45 unit.

I'm pretty sure that's the correct info...
 

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Discussion Starter #7
That's why we're all so interested in what kind of performance we'll see out of your RLS CUP-style intercooler.

Dyno testing completed last Sunday.

Executive summary: 2007 Lotus Exige S w/ rls Intercooler and 3.1" pulley, everything else stock including stock ECU.
Result: +26 horsepower at the wheels. We don't recommend the 3.1" pulley w/ the stock intercooler...

Dynos to follow. Waiting for electronic files from the dyno owner.

Dyno results from a 2008 Exige S240 within a couple of weeks.

A/F were great. Testing was done at about 550 feet ASL (above sea level).

The pulley is available as an add-on to the rls Intercooler. Stock belt works well, no slipping.

:D
 

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You used a diff diameter pulley with the stock belt? There was no play in the belt?

Those numbers are a great start. Can't wait for the dyno and AFR plots! How about daily-running behavior and reliability? What were the temps during the dyno?

Would love to see IAT, AFR, and ignition timing logs over the course of a few days, showing logs for daily driving (city/stop-n-go) and for "enthusiastic" use (on-track, or hard street driving)... and if those logs were recorded in 80deg+ temps, I think that would give us a great picture of the reliability and potential longevity for your solution.

Also, any MIL or codes from running that kit?

You've almost got me sold Thomasio. Your kit is the direction I would like to go if it works over the long haul. Those are just the kind of results I'm looking for and the price is right. I just want to go beyond the dyno numbers and see some daily-use logs. If those look good then I'm in for the whole darn kit!
 

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Keep it coming. I Wanna go fast!
 

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Discussion Starter #10
You used a diff diameter pulley with the stock belt? There was no play in the belt?

Those numbers are a great start. Can't wait for the dyno and AFR plots! How about daily-running behavior and reliability? What were the temps during the dyno?

Would love to see IAT, AFR, and ignition timing logs over the course of a few days, showing logs for daily driving (city/stop-n-go) and for "enthusiastic" use (on-track, or hard street driving)... and if those logs were recorded in 80deg+ temps, I think that would give us a great picture of the reliability and potential longevity for your solution.

Also, any MIL or codes from running that kit?

You've almost got me sold Thomasio. Your kit is the direction I would like to go if it works over the long haul. Those are just the kind of results I'm looking for and the price is right. I just want to go beyond the dyno numbers and see some daily-use logs. If those look good then I'm in for the whole darn kit!

PM me for my phone number, and we can chat. I have reams of data. They aren't fit for public consumption, but it is available.

Second gear pulls like first gear used to.

No engine fault codes. A/F ratio is great.

No slack in the belt: the tensioner is still in range after the pulley swap. I was prepared to use a 0.8" shorter belt, but it wasn't needed. No slippage whatsoever. (Watch out for the "tooth" profile of the pulley... some of the manufacturers don't have it right. If it isn't right, it doesn't engage the belt properly and it will slip.)

Results should be even better on an S240.
 

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MP62 on 07 Exige S(220)
MP45 on 08 Exige S220
MP62 on 08 Exige S240
MP45 on 08 Elise SC

Basically the non-intercooled cars use the MP45 unit.

I'm pretty sure that's the correct info...
Nice info!
 

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I'm running the stock pulley since it'd change the air fuel ratios, and I wouldn't change the pulley without a retune even with a different intercooler, all the pulley changes we've done have been retuned. This no doubt is one of the reasons lotus is making the new sc kits with pulleys that are very difficult to remove.

Its something i plan to do in the future with a retune though.

If you have data proving otherwise, you should consider posting it, in my experience with this, all the data that shows positive results is relatively short term and doesn't cover the gamut of conditions it'll be subjected too. Or as we hardware/software people tend to say, it works on my computer!
 

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Discussion Starter #13
I'm running the stock pulley since it'd change the air fuel ratios, and I wouldn't change the pulley without a retune even with a different intercooler, all the pulley changes we've done have been retuned. This no doubt is one of the reasons lotus is making the new sc kits with pulleys that are very difficult to remove.

Its something i plan to do in the future with a retune though.

If you have data proving otherwise, you should consider posting it, in my experience with this, all the data that shows positive results is relatively short term and doesn't cover the gamut of conditions it'll be subjected too. Or as we hardware/software people tend to say, it works on my computer!

As noted earlier, waiting for electronic files from the dyno owner.

A/F was unchanged. Boost went up about 6/10ths of a psi, much of the power increase was attributable to the increased efficiency of the supercharger.

With stock intercooler, there is no way I'd run a different pulley than stock.
 

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How does changing the intercooler correct air fuel ratios from the increased boost from a smaller pulley ?

P V=n R T
 

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Discussion Starter #15
How does changing the intercooler correct air fuel ratios from the increased boost from a smaller pulley ?

P V=n R T

The intercooler keeps the intake air temps down so as to avoid the detonation that one would surely induce with the stock intercooler and the 3.1" pulley.

The air fuel ratios were fine, we used the Dynapack directly into a bung upstream of the catalytic converter.

My car is available for inspection for anyone who would like to see it with their own eyes (or their own dyno).
 

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That doesn't answer how an intercooler changes the air fuel ratios for increased boost, it does perhaps answer why you're getting away with something temporarily.

What you're saying is, the larger A2A intercooler keeps temperatures lower for N amount of time which since the air fuel is now running leaner and would normally detonate, won't because the air charge is cooler.

So the answer apparently is, it is running leaner, but its ok since the air coming in is cooler, at least for as long as the efficiency of the IC can keep those temperatures down, at which point you think the stock ECU will retard timing enough at the right places to stop detonation ?

Since a lot of people track the cars, the IC is likely to heatsoak so then the IAT sensor on the IC will see those high temperatures and the stock S will pull timing like a mofo, but it may still be running leaner, unless it switches to the secondary octane map and it'll still be off, but it'lll drop some much HP that everything should cool, so the effect of the upgraded intercooler will be considerably lesser and the increased boost levels won't really benefit you since the ECU is now pulling so much timing you'll lose all that TQ/HP, its very aggressive, if you're in a hotter ambient temperature you may never cool the IC enough to get the IAT down to a level where the ECU isn't pulling substantial timing.

The ECU also knows the car is running leaner (or richer) and will begin to correct for it using the baseline it had set at the factory, which the car is no longer at since the boost has now increased, hence why short term testing often shows good results.

So as a recap, short term benefits from a larger IC, although running leaner than the already very lean stock tune, but when temps increases the engine is retarded so much it loses almost half its power.
 

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Discussion Starter #17
That doesn't answer how an intercooler changes the air fuel ratios for increased boost, it does perhaps answer why you're getting away with something temporarily.

What you're saying is, the larger A2A intercooler keeps temperatures lower for N amount of time which since the air fuel is now running leaner and would normally detonate, won't because the air charge is cooler.

So the answer apparently is, it is running leaner, but its ok since the air coming in is cooler, at least for as long as the efficiency of the IC can keep those temperatures down, at which point you think the stock ECU will retard timing enough at the right places to stop detonation ?

Since a lot of people track the cars, the IC is likely to heatsoak so then the IAT sensor on the IC will see those high temperatures and the stock S will pull timing like a mofo, but it may still be running leaner, unless it switches to the secondary octane map and it'll still be off, but it'lll drop some much HP that everything should cool, so the effect of the upgraded intercooler will be considerably lesser and the increased boost levels won't really benefit you since the ECU is now pulling so much timing you'll lose all that TQ/HP, its very aggressive, if you're in a hotter ambient temperature you may never cool the IC enough to get the IAT down to a level where the ECU isn't pulling substantial timing.

The ECU also knows the car is running leaner (or richer) and will begin to correct for it using the baseline it had set at the factory, which the car is no longer at since the boost has now increased, hence why short term testing often shows good results.

So as a recap, short term benefits from a larger IC, although running leaner than the already very lean stock tune, but when temps increases the engine is retarded so much it loses almost half its power.

Charlie -

You said: "So as a recap, short term benefits from a larger IC, although running leaner than the already very lean stock tune, but when temps increases the engine is retarded so much it loses almost half its power."

Have I in some way offended you Charlie?

Who said the car is running leaner. Let me be clear: it is NOT running leaner.

The A/F ratios did not change subtantially compared to the stock intercooler and the stock pulley.

Is it flowing more air? Yes. Is the ECU adding more fuel to compensate? Yes.

This isn't a competing product to your Gotham, Charlie. In fact, I think they would compliment each other nicely.
 

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Why do you think I'm offended ? Have i said anything of an emotional or combative nature, nor do i think its a competing product, had this been a thread like others on your products, i wouldn't have commented, but its a thread asking about maximum boost levels on the Exige S, I own an S, done quite a lot of work with them, so i'm passing on what I've learnt in that time.

I've suggested you prove your claim that air fuel ratios are not affected by an increase in boost.

More boost = more air.
More air + same amount of fuel = Different air fuel ratio, the answer is in the question itself.

Its the ratio of air to fuel, you change one, you should change the other.

Read the other threads where people changed their pulleys on the SC kits and claimed it was just fine, and now they've gone to a different method of ecu control that they're no longer fine and needed the AF mix to be corrected, and yet all along i've stuck to the same story, leave the pulley alone unless you correct the AF mix.

You're seeing it ok in short term because the ECU sees improper mixes and sets about to correct it, however since the baseline has changed, its working off an incorrect assumption.

Lotus now jams the pulley onto the supercharger so its very difficult to change, do you think they did this because of :-

(A) Its a conspiracy to make you buy the more expensive models, even though the expensive models will have the same change, but thats just because next year models will have an increased HP rating.

(B) It changes the tune enough to make it dangerous enough to cause running/engine problems and people either swap the pulley back and make a warranty claim, or they get bad press on the car being unreliable because the whole story doesn't come out ?
 

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Discussion Starter #19
CharlieX: "Why do you think I'm offended ?"

You seem to be making assumptions about the results, which I interpret as mistrust. Perhaps not.

CharlieX: " More boost = more air.
More air + same amount of fuel = Different air fuel ratio, the answer is in the question itself."


This is a false premise... you posit that there is the "same amount of fuel", and that just isn't the case.

By your logic of more = leaner, a car at sea level would run leaner than one in Denver.

As you surely know, the mass air flow sensor will see the added air mass and the ECU will adjust the fuel accordingly.

The smaller pulley on the supercharger is increasing boost, which is flowing more air. The increased airflow is not unseen by the ECU: it is coming through the intake.

Increased boost (within reason) isn't any different than lower altitude or colder denser air, both of which the ECU deals with just fine.
 

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CharlieX: "Why do you think I'm offended ?"

You seem to be making assumptions about the results, which I interpret as mistrust. Perhaps not.
But it isn't an assumption, its an opinion based on real world testing and experience of this exact issue. You've yet to show anything to disprove short term results, or any results at all. I've given you actual examples of cars and people on this forum that would further support my claims.

CharlieX: " More boost = more air.
More air + same amount of fuel = Different air fuel ratio, the answer is in the question itself."

This is a false premise... you posit that there is the "same amount of fuel", and that just isn't the case.
It'll only be false once you disprove it, tell me how the ECU adapts the fuel correctly to a new pulley size that it knows nothing of, not how it adapts the fuel for things it does know about.

By your logic of more = leaner, a car at sea level would run leaner than one in Denver.
You know i'm a great believer in coincedence, and it just so happens I've been having this discussion with two S owners in Denver who are having issues with their cars at altitude ( they are fine at sea level), I prepared a new flash for them last nite as a matter of fact, guess why they need a new flash.

As you surely know, the mass air flow sensor will see the added air mass and the ECU will adjust the fuel accordingly.
That is interesting because how I think it works is to look up the converted Grams Per Second from the MAF via a pre calibrated injector flow rate table to determine the correct amount of timing to feed to the injectors, that pre calibrated table is "pre calibrated" for guess what, the stock engine, which includes the pulley, not a modified pulley.

The smaller pulley on the supercharger is increasing boost, which is flowing more air. The increased airflow is not unseen by the ECU: it is coming through the intake.
What you seem to be missing is that in nearly all current and previous ECUs ( although it'll be changing in the next gen) is that they use complex mathematical formulas to derive the correct settings, those formulas are often so complicated that the ECUs of current days simply just do not have enough processing power to handle those calculations and run the cars sub systems, so the engineers pre process them on PC's and the like, they are then loaded into the ECU as a preset or pre calibrated table, these tables rely on the fact that the engine in normal operation does not change outside certain tolerances, the SC boost level will be 0.5 bar for instance, the sensors that feedback things like airflow are worked inside certain operating parameters, N amount of airflow = X amount of injector timing ( its vastly more complicated than that, but you get the idea )

Next gen ECU's will use processors powerful enough ( and since emissions laws are getting more complex and strict ) that they will be able to run these forumlas and not use precalculated tables for anything that may change, some race cars already run these systems, and they don't use narrow band o2 sensors.

Increased boost (within reason) isn't any different than lower altitude or colder denser air, both of which the ECU deals with just fine.
The ECU has a barometer inside it which deals with altitude ( though not for the mile high club) and it deals with denser area based on the pre set formulas set at the correct boost levels, it does not have the function to alter the input parameters that are not included in the simplistic 2D tables that are pre generated, it can only alter for things it knows about, or expects.

Again simple premise, the tables in the ecu come from precalculated operating parameters that are worked out before hand, they do not cater for unexpected changes.

At the end of the day none of this matters, just read the threads from people who've changed their pulley and after time have found the AF readings have drifted and the car is/or was running dangerously lean.
 
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