charge cooler on gt3. does this sound right?

[DAVES_GT3]

hi peoples
just checking my charge cooler pump to see if it was operating correctly. heard the easiest way if u dont know what your doing is to put your hand on the charge cooler when you have been for a spin. if its cold then its ok.
its slightly warm. you could leave your hand on there for ages without burning but its not cold
does this sound ok?
dave

[adrianmugridge]

It wont be stone cold but it should be cool, i.e. the same temperature as the engine bay is. If it's slightly warmish then I'd say that was fine.

Adrian
Sport 350, ex GT3

[cnh1990]

It should feel like cold metal even on a hot day.

After a spirited run immediately open the back and touch it. If you wait a few minutes the box will heat soak as the pump spools down in speed.

How many miles do you have on your car? That is a loose indicator if you need pump service.

>> Edited by cnh1990 on Monday 9th May 14:06

[lotusse89]

adrianmugridge said:

It wont be stone cold but it should be cool, i.e. the same temperature as the engine bay is. If it's slightly warmish then I'd say that was fine. Adrian Sport 350, ex GT3

Mine gets ice cold even on a 90deg F day! Calvin is right, it should feel cold to the touch. My chargecooler will be so cold that I think I'm getting burned at first.

Travis
Vulcan Grey 89SE
www.lotuscolorado.com/vulcangrey/

[adrianmugridge]

Well, I'm sure mine was never that cold. When the CC pump went south, the CC was hot to the touch and I had a major loss of power.

[DAVES_GT3]

hi
its done 58000 miles, its not hot but just luke warm.
it did go into paul mattys a few weeks ago and they never picked up on the pump. think they must have run a scan becuse they picked up the abs senser was faulty and the engine managment light had been on, cant remember what code but they couldnt sort what it was. said it was nothing to worry about.
the only reason i posted this topic is because it feels very low power at the moment but i do have a small hole and a crack in the manifold which im hoping is going to be welded tomorrow evening. would this have a big effect?
so i may know better then.
if anyone else has an idea on the low power if the manifold doesnt sort it id be greatful of the reply
cheers
dave

[adrianmugridge]

Does it have a water leak ? Mine was losing about 2 pints a week before I repaired the pump. I also had a cracked manifold and drove it for months like that with no problems, until it turned into a large crack that was !

Adrian

[DAVES_GT3]

not checked.
you think i may have a leak on the pump?
will have 2 try and get it up on some ramps i think.
leaks arent easy to find in past experience thats the only problem
dave

[cross-eyed-twit]

Hi Dave, the annoying thing about the chargecooler pump is that the impeller blades are rubber and can degenerate slowly causing an almost not noticable fall in performance. ie it is not pumping the fluid round to cool the cooler. Sometimes it goes all of a sudden, of course. The only real solution is to keep an eye on it by checking regularly and it has been suggested, even by Lotus, that the impeller should be changed at 18000 miles. Personally, I would invest in an electric pump, you can get these from various places like Demon Tweeks, SJSportcars I think supply them with a blanking plug for the old pump and John Welch in America
www.wcengineering.com/esprit/pump.html
This is the one I opted for and the pump was fitted by Steve Williams. It works faultlessly, the c/cooler is always cold to touch.

this is the one I've got (with blanking plug, don't forget) and with the exchange rate is a fair deal.
Cheers
Dom

[cnh1990]

I used to think my chargecooler was fine as it was lukewarm/warm to the touch. At the time I had no experience in this matter and nothing to compare it to. In my mind I was not sure, the chargecooler system sort of reminded me of a conventional cooling system and since it did not burn my hand I thought it was fine. My car at the time had 24K miles on it. After I read a few posts regarding this matter I ordered the pump rebuild kit. I removed the old pump and took it apart. The impellor resembled a round radio knob with all the fins gone. In the small confines of the pump chamber if one fin snaps off all the other fins collide with the remants at very high speed and they all disintergate as the exit hole of the pump is smaller than an intact fin that has sheared off.

After the rebuild I touched the box after a spirited run. It felt like touching a cold water pipe in the basement even on a hot day. Not say it actually was that cold only that it felt that way. After a few minutes at idle (heat soak) it did feel more on the ambiment temp side.

While many complain this pump impellor does not last very long, I look at it as a regular routine replacement item like changing a belt. It cannot be compared to a regular water pump. The shaft that drives the chargecooler pump was in the older non ECU cars was what drove the distributor. It spins very fast and matches the engine RPM's so in my car quite frequently used to spin in 5K+ rpm range as in every time I drove the car.

There has been a few different soultions to this issue. An electric is an option and provides a static flow. I suppose the electric pump has an advatage during a hole shot minimizing heat soak at idle, in my opinion the original is as good as the electric when the Lotus is driven robustly as it was meant to be driven. So I went with a rebuild as it takes me about 30 min and a few dollars every several years which is not too much to ask for. Another thing was the alternator is pretty marginal and with my American habit of using Air conditioning a lot and the 4 X 100 audio amp the prospect of adding another electrical item was iffy for me.

The block off for the pump port is not a new item. It is found on the non chargecooler ECU equipped Esprit's such as the 89 model and can be found in the SJ on-line parts list.

I must add one final note. I looked into my header tank and it was incrusted with corrosion. I used CLR to descale the header removing very large chunks of rust. At that time I thought is this what is circulating in system? I unbolted the chargecooler box from the engine back flushed it and black crap shot out of it, yuck very nasty. I took an old garden hose and cut the end off and using a barb fitting hose clamped it to the system return and another hose clamped to the other side running into a bucket as I was curious as to what would come out of it. I ran the hose to my hot water faucet and turned it full blast. Only a trickle came out at first, then a big blast of water and black gunk with a few remnants of impellors, big chunks of scale, and rust. It took a few minutes for the water to run clear. The sediment was ugly.

Oh well sorry for the long post.

It is nice spring day in Minnesota today, these are the times I miss my former Esprit the most. The new owner likes the car so much he has invited me to take my former car for a day long spin with my son. Maybe I will take him up on his offer one day soon.

Calvin

[DAVES_GT3]

thanks for the post calvin
one quickie to anyone out there really. i havent found the pump yet but not had a good look really. is it accesable from underneath the car or does it have to be done from the tot? is it anywhere near the thermostat?
cheers dave

[okc-esprit]

Take off the oil filter. You can then follow the hoses down to the pump.

[Htown]

lotusse89 said:

adrianmugridge said: It wont be stone cold but it should be cool, i.e. the same temperature as the engine bay is. If it's slightly warmish then I'd say that was fine. Adrian Sport 350, ex GT3 Mine gets ice cold even on a 90deg F day! Calvin is right, it should feel cold to the touch. My chargecooler will be so cold that I think I'm getting burned at first. Travis Vulcan Grey 89SE www.lotuscolorado.com/vulcangrey/

Colder than ambient temps?

[adrianmugridge]

Ambient is what I'd say mine always was. It got very hot when the CC pump was not working.

Also, it was fine until about 50k miles. I bought the car with just under 5000 miles on it, soi t had not been replaced until I did it.

[paul c]

I could touch my chargecooler,
so considered it working fine.
Had it took off as i was losing
coolant from the system and then
finding it on the dipstick...

Decided to upgrade to electric rather
than have the old pump put back, a good
move as it happens because my pump was
100% knackered. It is now COLD, no excuses,
it really is VERY cold, like a beer.

Have promised my car never to let it get
that bad again, no point having an SE if
the Chargecooler is stuffed!

outlet blocked:


Impeller remains blocking outlet:


Impeller condition:


Emulsification water to oil:


Blanking plug: (by PNM Engineering)


And the electric one:
www.demon-tweeks.co.uk/catalogue/product_detail.asp?PCODE=DCP9001&GRP=MP091&PGRP=M006&CLS=MSPORT&from=search

[Htown]

So, someone want to explain how it's physically possible to chill the coolant below ambient?

I just don't see it happening regardless of what type of pump is used, considering the design and placement of the a/c condensor/chargecooler radiator.

Craig

>> Edited by Htown on Wednesday 11th May 00:22

[lotusse89]

Htown said:

lotusse89 said: adrianmugridge said: It wont be stone cold but it should be cool, i.e. the same temperature as the engine bay is. If it's slightly warmish then I'd say that was fine. Adrian Sport 350, ex GT3 Mine gets ice cold even on a 90deg F day! Calvin is right, it should feel cold to the touch. My chargecooler will be so cold that I think I'm getting burned at first. Travis Vulcan Grey 89SE <a href="www.lotuscolorado.com/vulcangrey/">www.lotuscolorado.com/vulcangrey/</a> Colder than ambient temps?

The air temperature comming out of the c-cooler, at the MAT, is usually just a few deg above ambient, eg. 95deg on a 90 deg day. However the c-cooler heat exchanger box on top of the engine does get much colder than ambient temperatures in the engine bay.

While driving at some speed, and getting forced convection over the front radiator fins, thermal energy is being pulled out of the fluid by conduction through the radiator metal. The large amount of air flowing through at speed has a greater heat capacity than the fluid and radiator put together, even though convection is usually a pretty inefficient transfer. Even though the air is at a constant temp, if you were standing still, because you are constantly moving through the air, it is able to draw out more thermal energy than it would if you weren't moving. Therfore the fluid becomes cooler than ambient air temperatures.

So this colder than ambient fluid gets pumped back to the engine, slightly increasing in temp during the trip. It then goes through the charge-cooler heat exchanger, where the heat conduction is even greater through aluminum (heat exchanger) than it is through steel (radiator). So the heat exchanger has cooler than ambient fluid flowing through it, and it has fins with a whole lot of surface area for efficient transfer. The air comming out of the turbo is also expanded (loss of pressure and drop in temperature) into the charge-cooler heat exchanger box). Since the air is expanding into the box it is ready to shed the heat due to expansion, and there is alot of cold aluminum at a much lower temperature. Heat always transfers from hot to cold, so the heat is drawn out of the air. As the air leaves the charge-cooler heat exchanger it is re-compressed through the smaller outlet port, though it has already lost much of the thermal energy.

The fluid is flowing fast enough through the box that it doesn't see a raise in temp. it just keeps dropping until it reaches equilibrium for whatever all the variables are at the time (speed, boost, rpm, ambient...)

Because the system isn't perfectly efficient, and due to the recompression after the cc-box, the air is just above ambient. But it does a pretty good job.

The box however, is below ambient!

Using a Peltier effect cooler (two sandwiched plates of ceramic with current flowing through them) you can freeze water in a spoon on a desk inside a warm building... the spoon gets cold, but on the other side of the equation a block of aluminum (heatsink) gets hotter.

Travis
Vulcan Grey 89SE
www.lotuscolorado.com/vulcangrey/

[cnh1990]

Htown said:

So, someone want to explain how it's physically possible to chill the coolant below ambient? I just don't see it happening regardless of what type of pump is used, considering the design and placement of the a/c condensor/chargecooler radiator. Craig >> Edited by Htown on Wednesday 11th May 00:22

I don't really think it is that much colder but it is a perception that it is. We are talking about a field test and not measuring with a thermometer. As humans we encounter and feel temps differently than inanimate objects like metal. Metal feels no heat index or wind chill that the weather man on TV refers to. In 90F ambient temps there is the current heat index and humidity, many times our bodies will feel hotter than it really is coupled with heat blast from the engine compartment. So when one touches the chargecooler box it will indeed feel or appear to feel ice cold. It feels just like touching a household cold water pipe that is running.

OKC-Esprit is correct. Remove the oil filter (I also like to slide the oil cooler plate off too), cover the the filter inlet with a plastic bag and secure it in place. Remove spark plug leads from the coil packs, remove the hoses if you can, and unbolt the single bolt on the pump dog ear, twist the pump slighty to offset the dog ear to use a screwdriver to gently pry the pump rearwards (it will pop loose) and then remove the pump.

The mating of the pump drive is what I called keyed or offset and the drive pins only go in one position. More than one person I knoe of has snapped off the dog ear on either the pump or the engine side by not fully seating the pump in the key and tighting the retaining bolt. It is a bitch when one snaps the dog ear off the engine side as it will have to be welded back on. It rumored when this happens one can hear an Esprit owners screams across the USA.

Now this is the part a lot of people don't tell you.
When the pump has been cleaned and the pump chamber a part take the old impellor and replace it in the pump chamber, clean and lube the shaft and o-ring with motor oil and slide it in the drive hole. apply slight pressure and while rotating the shaft using the old impellor as a knob (it looks like one so I used it like one). When you find the correct position it will click in to home. Align the dog ears then remove the pump straight out without rotating the keyed end or pump housing. Just like how one seats the distributor in the older cars. You can pratice in this way a few times so you will know the feel of it seating correctly.

Note the location of the keyed end and mark on the shaft marker where it is. Proceed with the rebuild and making sure the key is still in the right position. If you have to adjust the the key after assembly make sure to only turn it in the correct rotational direction that the pump was made to go or the impellor blades will fold back and be damaged. Attach the pump as you have practiced.

Hope this helps.

Good luck,
Calvin

BTW Travis's explanation is way beyond how I could have explained it. I would get along well with this fellow, almost sound like I'm chatting with Jim McFadden.




>> Edited by cnh1990 on Wednesday 11th May 02:21

[lotusguy]

cnh1990 said:

"...Hope this helps. Good luck, Calvin BTW Travis's explanation is way beyond how I could have explained it. I would get along well with this fellow, almost sound like I'm chatting with Jim McFadden.

Calvin,

That's funny, I was reading this thread and thinking the same thing about you. BTW, it was great seeing you last week and checking out the Boxster. I have done a couple suspension mods since you drove it and they have improved the handling even more. Stay in touch.
Happy Motoring!... Jim'00 Boxster

[lotusse89]

cnh1990 said:

BTW Travis's explanation is way beyond how I could have explained it. I would get along well with this fellow, almost sound like I'm chatting with Jim McFadden.

Actually Calvin, we have met! LOG 22 in Wisconsin.

Travis
Vulcan Grey 89SE
www.lotuscolorado.com

P.S. I think it's funny how Jim always ends his posts on Pistonheads with "'00 Boxster" rather than with his "'85 Turbo Esprit" tag line. I hope he's not ashamed to know us