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Jimjitsu

charge cooler temp?

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I am not sure what you mean exactly. Do you mean "At what temp does the charge cooler start to operate and cool the air down ?"

If so, there is no trip point, the incoming air is cooled constantly. The water pump which feeds the charge-cooler, is driven permanently directly by the engine, so as soon the engine runs, the charge-cooler operates.

If you mean "what maximum temperature can the air reach", then according to a mag I have, the air can reach up to 150

Edited by troutrou

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I know the charge coolers have a rpm operated pump which breaks a lot >< what i was wondering is what maximum temperature will you ever see on MAT so 65c is the hottest it will ever get?

Edited by Jimjitsu

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Yes 65 is the max (according to my information at least) at the charge-cooler outlet. But as you said, the charge-cooler pump has a long history of degrading over time (it's made of rubber, so it perishes), decreasing the charge-cooler efficiency, so it will have produce higher temps. Mesuring the air-temp (using Freescan for example) while driving hard, is a good way to check the "health" of the pump. If you can't get it over 65 no matter how hard you push the engine, then it works fine, but if it gets noticebably hotter than 65 then you know it's time to replace the pump.....

Edited by troutrou

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There is an option to change this to an electric device, charge cooler should be cold to the touch if yours is above stated temp then it may be prudent to change, there is a thread on this forum and on Lotus esprit world if I remember correctly. The choice is yours. Mine is cold to the touch, never had any problems touch wood.

Take care

Dave

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Mine is electric driven and rarely - even under sustained boost in 5th gear - ever gets much higher than 40c

99% of the time its under 30 or 10c above ambient.

Temp really makes a difference with not only peak boost but how long it can be sustained for.

Someone coined 1hp for every 1/2 degree C and I wouldn't doubt that for a second.

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I concur with Jon on this.

Mine has an electric pump and I also have a hyper fast reacting accurate k type thermocouple in the end of the chargecooler.

Compared to ambient i usually get the MAT down to just above ambient trundling about below 75-80ish (ultra low boost if any) and if I use some proper boost it can sometimes go up to around 40 max. never seen the 60-65ish others mention apart from when the manual pump didnt work for toffee when I bought the car.

The real test if how it comes back down after you having given it the big fat overtake past 6 cars with the trademark 30-140 blast that these cars seem so good at. you may see a peak near 40ish on mine, but it falls back swiftly as you annilate the brakes after the afor mentioned blast.

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Think I will go for the electric option im struggling to get a good log with freescan it keeps crashing after a few minutes of running. Plus the plug under the dash does not work so I have to plug the lappy in boot go for a drive and hope it logs it all ><

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Hi All,

An electric pump will not increase cooling efficiency of the whole setup.

The overall cooling effect is only dependent on both radiator and cooler efficiency.

It does not make any difference if the pump is pumping more or less volume/time !

IMHO its some kind of fairy tale that the elctric pump will give lower temps. What it actually does is the fact that you eliminate the impellor failures and the original look of the whole engine bay.

Cheers

Marcus

Edited by Paula&Marcus

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Mines on electric pump too.

cheap mod really, ebay for the pump

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I'll probably get shot down for this but I was really interested to read Marcus' comment above of;

"It does not make any difference if the pump is pumping more or less volume/time !"

One of the arguements for switching to the electric pump was that it was more effiecent becuase it was not tied to engine RPM and maintained a higher flow rate becuase it was always pumping a consistent greater volume rather than the existing setup.

I'm not saying Marcus' is wrong but given there have been plenty of discussion on the forum that faster/bigger volume was better, I am interested to now see the opposite view being put forward and to see if anyone could support an arguement either way to confirm. If bigger faster electric pump was actually better?

I understand that increasing the CC or CC Rad would give an improvement but does improving the pump improve the system on its own ?

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I have not read the past discussions about it, but my opinion as a technician though not specialized in thermo-dynamics :( is that increasing flow behind a certain limit is not going to pick up any more heat/energy from the CC pipe fins, since the water just wouldn't have time to absorb the heat. Once you have reached this maximum flow/asymptote, the only way to pick up more heat/enery is to increase the area in contact with the water, and I think this is precisely why the CC in the sport 300 is larger, in order to pack more fins. Of course, at the other end of the sytem (the nose of the car..), if you pick up more energy in the charge-cooler, then you must also have more surface to dissipate it in the front radiator, and I believe that's why the Sport 300 came with no air-con originally, and plumbed the air-con rad with the CC rad in order to increase cooling capacity/efficiency.

The sport300 may have come with air-con at some point... well it just means they decreased cooling efficiency for some confort, it's up to the owner to decide if this compromise is okay for him...

The mechinal pump flow, hence CC efficiency, varies with engine RPM, sure. But, turbo speed hence boost hence air temp entering the CC, is also directly related to engine RPM. So all in all, the CC is given the efficiency that it needs at any given RPM: at low RPM/boost, low flow/efficiency is enough to keep things cool... because they aren't that hot to start with. And at higher RPM/boost, it enjoys higher flow in order to cope with the extra heat. The CC efficiency rises in unison with the compressed air temp. As far as I am concerned, the Lotus design is perfectly adequate !

The only benefit/goal of the electric pump is to get rid of the rubber impeller that degrades over time, hence degrade performance progressively, viciously, and is not easy/fun to maintain/replace. The electric pump is easier to get at.

But I feel like Marcus about the electric pump: it looks out of place and "un-natural" in the engine bay, like an after thought, grafted on. Doesn't look good and not very elegant technically.

It feels to me just like a human heart : an artificial electric pump in your pocket, with tubes going out your body, and a battery and switches and wires all over the place, sure keep you alive and are more reliable and durable than mother nature's item. But a healthy human heart is also perfectly able to do the job. For the person dealing with this artificial heart, there is no doubt they would feel more confortable with a real human heart (even if not their own) in their chest, with no gear around... it would feel more "natural".

So what I would do is replace the rubber impellor with one made from a more durable material that will not degrade (as it IS available), just like PU bushings get rid of the problem of the perishing OEM rubber bushings.

Edited by troutrou

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Has anyone swapped out there fully working mechanical pump for a electric and done before and after readings? not sure to get the uprated impeller or go electric now : /

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I guess we should also bear in mind that on top of the perishing OEM rubber impeller, the CC efficiency can be notably decreased by all the debris that so easily clog the fins of all front radiators.

So first clean those well using compressed air (or with a garden hose but not sure how the electrics will like that...) , then only start measuring CC efficiency to decide how healthy or not the impeller really is...

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Hi All,

An electric pump will not increase cooling efficiency of the whole setup.

The overall cooling effect is only dependent on both radiator and cooler efficiency.

It does not make any difference if the pump is pumping more or less volume/time !

IMHO its some kind of fairy tale that the elctric pump will give lower temps. What it actually does is the fact that you eliminate the impellor failures and the original look of the whole engine bay.

Cheers

Marcus

Before making a sweeping statement thus, be informed that volume of fluid has a large effect on watercooling.

Overall cooling effect is NOT ONLY dependant on the heat exchangers - air flow and fluid exchange rates also affect it significantly.

The real truth of the matter is that if you want to have the best out of the chargecooler system you should balance the chargecooler, the chargecooler radiator, air flow and the pump volume to match each other and compliment each other. Ideally they should all be constant - however airflow is not in our case.

Regarding pumping rates - If you move the fluid too slowly it dwells in the hot and cold parts of the heat exchangers and soaks too much heat to lose, if you move the fluid too quickly you do-not allow the fluid to stay in the exchangers long enough to convey the heat in and out - both are bad for the system - this is why the optimum / constant flow rates are necessary, or more desirable IN MOST CASES.

In straight line 70mph 30% throttle and low boost - no, there will be no real difference.

However when you're on track or using the car enthusiasticly the RPM of the mechanical pump is in effect, stop-go-stop-go or in pulses, thats not very good for an heat exchanger as mentioned above it promotes the fluid to dwell in hot/cold areas and not do as much work as it could.

What you ideally want is a constant RPM to give a better average cooling across a different set of circumstances.

One thing for certain though is the mechanical driven pump's alloy body is bolted onto the engine / oil pump and so helps to heat up the nice cool water resulting in a temperature rise - the electric one is isolated from the engine and you get a heat reduction there for starters.

End of the day the proof of the pudding is in the eating, I've never seen a standard car with MATs as low as mine and they changed right after I swapped my perfectly healthy chargecooler pump for an electric one. You can quote all the facts and pseudo science you like - I have the results I did with the car in front of me, which show an average temp drop of about 10-15 degrees and better response to cooling esp at idle.

When I went out in Bib's car his MAT ranged from 30-50 degreec C

I took mine out a few earlier, similar ambinet temps, doing 4th gear high boost tests and mine does 14-20 C

In 3rd gear I was getting 12-17 C again at sustained periods of max boost.

Personally I would never ever go back top the mechanical set up, the sheer fact the electric pump doesn't draw heat from the engine itself is testament to that. Even if I didn't get cooling benefits, the cost, ease of fitting and the maintenance issues tip it every time.

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Other thing is that even if the

Edited by troutrou

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There is no problem running cooler (exception later). The physical limits of the thermodynamics will limit how much of a temperature difference you can feasibly achieve though. You won't be able to break the laws of thermodynamics...

It is pretty difficult, without using too much energy or exotic liquid nitrogen cooling, to get below ambient temperatures. And at some point there are diminishing returns... But the Lotus system can get pretty close to ambient, which is a lot better than the air after it leaves the turbo, or even an NA car intake tract.

The only realy problem with getting too cold is if you exceed the calibration range of the ECU. Then the computer doesn't necessarily know what to do. This happens with the Esprit, if you have mostly driven on warm days, and then then next time you drive the car is very cold <freezing for instance. The car will be making more boost than it had been calibrated to and the ECU will go into the overboost shutdown mode.

Usually you can disconnect the ECU fuse for a bit and let it relearn the new lower temperatures.

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Yea Thanks Jon, I was just about to say that... :(

I'm with Jon, electric cc pump all the way.

Edited by CarlC

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On a sarcastic note, with so much enthusiasm for electric pump, I would like to point out that the exact same problem and technical arguments hold true for the engine (main) cooling system. So, to be consistent, all the people in love with the electric CC pump should logically also replace the engine water pump with an electrical one ! But how many will actually do it... somehow I feel they won't be as numerous :(

--

Vince, running away fast...

Edited by troutrou

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Chaps - read :

http://www.lotusespritworld.com/EGuides/ET...argecooler.html

(pay attention to the pics of failed chargecooler pumps)

Also links in there to electric pump manufacturers.

http://www.lotusespritworld.com/EGuides/EM...argeCooler.html

Even Lotus endorse it.

Vince, if what you say is true why is it the Esprit has one of the worst braking systems known to man ? :thumbsup:

Lotus were never rolling in cash and development time - technology marches on and there are always better things to come along.

It's quite possible back 20 years ago when this system was being designed electric pumps were not common place and or expensive compared to todays market.

Their performance might even have been lower than today's (most likely they were).

The idea (at least for me) is not to reduce the minimum temperature but the peak/average temperature.

There comes a point where you put so much effort / energy into chilling the water it takes more out of the system that it benefits from.

If what you say is true, why didn't lotus fit the very best of everything to the Esprit ?

Getting back to the chargecooler - why did they not insulate the chargecooler body on top of the engine, why did they not run the cold water pipes away from the 80 degree C heater pipes in the chassis ? If they had they would have ended up with something like the McLaren F1 whith inkernel exhuasts and gold heat shields all over it.

The benefits of a healthy and optimal chargecooler are possibly one of the best things you can do to the car performance wise after the obvious induction and exhaust mods.

If in doubt do a boost test at MAT 20 degrees C vs MAT 40 C and see how quick the car accelerates.

IMO the standard shaft driven pump vs a good quality, high delivery motor powered pump is a no brainer - I would replace it on the reliability issues alone, the gains are an added bonus.

EDIT : I used a Johnson Pump simply for it's build quality.

http://www.johnson-pump.com/JPMarine/produ...ation/cmco.html

On a sarcastic note, with so much enthusiasm for electric pump, I would like to point out that the exact same problem and technical arguments hold true for the engine (main) cooling system. So, to be consistent, all the people in love with the electric CC pump should logically also replace the engine water pump with an electrical one ! But how many will actually do it... somehow I feel they won't be as numerous :(

Vince you are a silly one :devil:

You dont need that sort of delivery on an engine coolant pump becuase the majority of the time it is regulated by the thermo stat, keeping the water as cool as possible is not the main task of the system, keeping it at 82c is ! As long as engine temp is kept around 82-90 degrees it has no bearing on performance - same can't be said of the chargecooler eh ?

Edited by Jonathan

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> Vince, if what you say is true why is it the Esprit has one of the worst braking systems known to man ? :cheers:

Read my posts again ;-) I did say that for SOME aspects of the car, there were no-brainer improvements... I did have the SE brakes in mind when writing this ! :(

Not all Esprit brakes are crap though. The Sport 300 and 350 brakes are not bad ! :cheers:

> It's quite possible back 20 years ago when this system was being designed electric pumps were not common place and or expensive compared to todays market.

I did think of that and hesitated to bring that point... but refrained to avoid bloat...but I could not help to think that the Renault 21 Turbo (introduced in 1986), hence who was contemporary of the Esprit SE and even the old Guigiaro Turbo, did have an electric water pump (to cool the turbo bearing down after the engine has been stopped). So this kind of pump was clearly available.

Still on the R21 (yes, I admit, along with the Esprit, the R21 is the only car I have a fetish for...), albeit the "TXi" version (Sporty N/A variant), the brakes were much better than the SE (30+mm larger in diameter !), even though both cars appeared on the market on the same year (1989), and despite the R21 TXi being obviously hardly a supercar and hardly as expensive as the Esprit.

So I can't find an excuse to Lotus, and often am angry about them, for putting brakes significantly crapper than contemporay cheap saloons, when logic would have been to put significantly BETTER brakes, not the other way around.....

> If what you say is true, why didn't lotus fit the very best of everything to the Esprit ?

Cost ? Even multi-million pound cars don't use the best... just too expensive.

But Lotus do wonders at the quality/price ratio I find, with a consistent package (bar the brakes early Stevens cars)

>Getting back to the chargecooler - why did they not insulate the chargecooler body on top of the engine,

> why did they not run the cold water pipes away from the 80 degree C heater pipes in the chassis ?

> If they had they would have ended up with something like the McLaren F1 whith inkernel exhuasts and gold heat shields all over it.

Maybe you are right, maybe not... it's diffciult to discuss all the decisions they made, without reading the desing notes, diary, calculation that the designers did at the time.

I would like to believe that whetever they did, they did it knowingly and that whatever compromise/trade-offs they made (like not insuating thjis or that) must have weighted carefully, and judged not to annihilate the benefit of the rest of the CC design, and it's overall efficiency.

Just because a system look simple from the outside, doesn't mean that they haven't put lots of thought and skills in it. Just like the whole Esprit really: it's dead simple technically comapred to even the cheapest of taoday mass produced low end car.... yet how comes only Lotus managed to make something as nice to drive (and own generally) as the Esprit ?

Suispension is simple right... just a coil and a damper... so how comes many manufacturer come to Lotus to design their suspension or chassis altogether ?

Lotus has alwyas been about engineering more than anything else, even more so today I believe, so I do tend to think they do know what they were doing (even if what they did might not be what some owners would have liked).

> The benefits of a healthy and optimal chargecooler are possibly one of the best things you can do to the car performance wise after the obvious induction and exhaust mods.

> If in doubt do a boost test at MAT 20 degrees C vs MAT 40 C and see how quick the car accelerates.

I would be interested in reliabvle measurements of this... looks like your Esprit must do the 0-60mph in 4 seconds not 5 :thumbsup:

> Vince you are a silly one :clap:

Yes sorry. Looks like my come back on the forum is less discrete than I anticipated, sorry about that.. I will go and hide :devil:

Edited by troutrou

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I would be interested in reliabvle measurements of this... looks like your Esprit must do the 0-60mph in 4 seconds not 5 :(

Vince, I have the freescan readings, I dont need anymore reliable.

Cooling the inlet allows you to boost more often and allows boost pressure to build quicker - knocking a second off 0-60 times is a component of 60-100 horse power, nothing like what we are talking about here.

What you have to realise is the more you boost and the more often you do it the more heat builds up in the chargecooler system - it gets to a point where it is saturated as the chargecooler cannot shed the head and the turbo simply cannot compress the hot air to a level where it generates excessive heat.

By cooling the inlet you are not lowering the miniumum inlet temperatire but the average this has negligable if not zero effect on 0-60 times but lends it self to more drivability in the 30-120 range and sustained boosting.

Without being rude it's pointless having this discussion - it just ends up going around in circles.

Best thing to do is to pitch up 2 cars side by side, take the measurements and be done with it.

Edited by Jonathan

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