14 replies to this topic

[cweeden]

Hi All,

I am pulling the motor over the winter (hopefully) to tidy things up a little and I am seriously considering adding a charge cooler setup. I would like to investigate the many different implementations other owners have completed to capture as much innovation as possible.

Ideally I would like to keep my boot space. I might consider eating into it a little if there is a compelling engineering reason to do so (but it would need to be a very good reason).

I do not know where to start with any calculations to ensure everything is matched to the task. I mean how do you calculate the amount of cooling required, what size coolers to use, are two twice as efficient as one, what size radiator is needed and how to fit it etc etc...?

So I am reaching out to the likes of Mark TC, Ray Gardner (your info looks like a power point presentation, I would love a copy if possible?), Mike S and anyone else I have missed (sorry) who has carried out this modification for help and ideas.

Do you have any more information about your installations regarding the components used (specs and suppliers if possible) and any pre and/or post installation performance results. Also any discarded ideas and why they didn't make the grade?

The PWR Performance Products barrel coolers are top of my wish list currently ( http://www.pwr.com.a...=products/s=is/ ), the description on a partner website ( http://www.advancedv...in_page=privacy ) seems to make sense but I might just be being sucked in by a good marketing pitch.

Also in hind sight after living with the installations for a while would you do it again and would you do it differently or keep it all the same?

Many thanks

-Chris

[mike_sekinger]

Hi Chris,

I´ve sent you an email.

Cheers,
Mike S

[Che]

I designed an air to air intercooler for Lotus V8, unfortunately something happened to my engine before I can even test them.
I don't want to hi-jack your thread, I will try to put some write-up and pictures in the "restoration project section" sometimes.
Here is the initial picture http://img507.images...g</span></span>
http://img203.images...g</span></span>

To summarize, water intercooler is more effecient vs the air to air. My car used to have liquid intercooler but way too complex, lots of things to go wrong, a mile of hoses, weight issue, heat exchanger placement issue, water pump to die, water to leak, water maintenance (winter-summer), clog the engine bay. I pulled them off. (By the way, this is just my design & opinion...I'm in no way to offend those with water intercooler system. My air to air is not yet tested & not proven)

Air to air is simple like brick, leave it there, less weight & no maintenance. The downside, you have to be very innovative to find a solution how to cool the intercooler matrix. Tough to accomplish in the mid-engine car.
I'm very confident I can make it to work. Fresh air is the key. I know where to get 'em. If F40 can do it, I think I can make it to work in the Esprit v8 too.
Simplicity is my priority.

For the meantime, Gunter helping me & giving me a few pointers on the engine rebuild. Its gonna be sometimes before I can test my air to air....it's unfortunate.

Edited by Che, 14 September 2010 - 01:38 PM.

[mike_sekinger]

Oops.... I bet you Pa is happy with you

[cweeden]

Hi Che,

I can't follow the links, can you check them please.

I would be interested to see where you decide to place the inter coolers and how you duct air to them if that becomes necessary.

cheers

-Chris

[Che]

sorry.... try this Chris
http://img507.images...y172010056.jpg/
http://img203.images...y172010055.jpg/
fresh air coming from two side scoops
http://img214.images...y172010051.jpg/
two spal fans getting fresh air from the bottom of the boot trunk
http://yfrog.com/bc2252007015j
http://img571.images...y172010044.jpg/
http://img13.imagesh...y172010036.jpg/

oh! I have two water squirter (from the regular wiper/windshield switch) in the front of the intercooler, just incase of heat soak.
I have no picture of the squirter.

Edited by Che, 14 September 2010 - 05:34 PM.

[cweeden]

Hi Che,

That is a very neat installation. As you point out the simplicity of intercoolers is very appealing. How much work was required to choose the path of the ducting and how much body modifications have you done. I can't seem to find a picture showing that area without your ducts (I haven't looked that hard yet to be honest :-) ).

Do you have any pictures which show the whole boot space to better guage how much is lost to the intercoolers?

I will keep an eye out for any results you get with great interest.

cheers

-Chris

[Che]

Chris
I did not lose any space on the boot. I did not use the original Lotus boot, I kept it for future. I simply fabricated a stainless sheet and bent it like a
a letter "Z" (a bit slant). Very simple thng to do, one unit, no welding just using the break tools. The stock boot has a hump in the front of the engine.
The intercooler matrix is rectangle and flat, I need to accomudate the shape. Here is the picture of the boot space:
http://img237.imageshack.us/img237/9807/2252007025.jpg Note: the bottom grill is where I get a fresh air use for the 2 spal fans.
Here is the good picture how much space left in the boot: Note the crossmember of the car, I stopped there, the stock boot is in the same place.
http://img401.imageshack.us/img401/8230/may172010054.jpg Oh! i can still use the stock engine cover on the top of the boot ( I don't have picture).
I used the Esprit brake or engine bay scope to cool the intercooler matrix http://img828.imageshack.us/img828/4697/may172010056.jpg
I found a picture of the air to air intercooler with 2 water squirter in the front of the matix http://img829.imageshack.us/img829/8704/may172010055.jpg
I don't have a plan to use the squirter ( I used the stock windshield water, pump and switch) but it's simple precaution just in case there is a heat soak. I know Subaru STI & WRX uses this simple system as stock to their cars. http://img13.imageshack.us/img13/7839/may172010036.jpg
Lastly, I bought this unit to measure my "in-out" air temperature

Unfortunately, my car is dead....I can't test.

[Günter]

che, I've question slightly *off topic* -do you really need to weld an bracket onto the catalysts ..if the exhaust is fixed by an exhaust 'rubber thing' near by , and vice versa ?!

Looks strange an inconsistent to me.. .

[Che]

Gunter--what happened was, the exhaust system keeps cracking. Since I put a bracket on the muffler (oh by the way, its not a catalytic) I never had problem since. Car has no catalytic.
I don't have the original picture but I did the same system to a friend's Esprit. Mine is exactly the same as his.
Suprisingly tolerable.

[cweeden]

Also off topic, anyone know the weight of the engine on its own (with ancilliaries) and also how much for the engine and gearbox combined?

cheers

-Chris

[mike_sekinger]

Hi Chris,

The engine is a little over 210Kg dry.... from memory the gearbox is a little over 50Kg.

You planning some weight-lifting?

Cheers,
Mike S

[Günter]

As so, the question is why there is this flexible support on the tail-pipes ...if it is stiff all in all.

anyway , without real catalyst and only those small mufflers/silencers together with 'air chargecooling' instead of additional warter -this should be an really ligt 'backend' on your car !



But those mufflers look nice, that stands without any questions ..I would wounder if we could get that system over her to pass on TÜV/MOT certifications -must be really loud than ?!

[WEllison]

Hi Chris,

Intercoolers for the Esprit are all about packaging, as space and location are at a premium! This is why the air to liquird intercoolers are the most popular, they are smaller, and yes more complicated. The biggest problem in designing a system is getting valid data from the intercooler core and heat exchanger manufacturers. They just don't publish the techinical data. I was able to find published performance data on Spearco cores (plate & bar core) built into the size of intercooler assembly functionally correct for use with the Esprit, but that assembly consumed to much rear trunk space. I was able to find a equivelent core from Bell Intercooler which I could fabricate into my own custom assembly which did not consume as much trunk space (almost none at all). Working with a Bell Intercooler engineer I took his word that the core was equivelent, actually better, than the Spearco core, as Spearco discontinued that paticular core anyway. In the end the Bell Intrercooler cores exceeded my expectations. I had to build the system on faith, however..

Before selecting the intercooler cores you must decide on how much heat you need to remove from the inlet air stream. To do this you need to determine how much boost you intend to run, get the T25 compressor (or alternative turbo) map and use the Spreadsheet provided by Garrett turbo charger (turbocalcs.xls) and determine the resulting turbo exit temperature. I have discussed with Lotus at what temperature the ECU begins taking defensive action with timing and boost reduction based on IAT. It seems that 120* F is a very good target to try for. Now you can determine the BTU's to be extracted using standard thermal equations. These same thermal equaltions can be used to size the water pump and heat exchanger. You will have to define for your own purposes what MPH, ambient temp, static pressure drop and percentage of time the engine will be at the boost level you want to run. Just like obtaining performance data for the intercoolers, getting performance data on heat exchangers is also a problem. Most radiator manufacturers rely on the core ( tube & fin) manufacurers for this information. They are not inclined to let you work with them. I was fortunate to find one.

There are many intercoolers available via the internet, but you will never find any techinical information. In the end, if all you want is a enough cooling for a red light drag race almost any system with some water reserve, and some recovery time between red lights, will work. But if you want a road race car with sustained boost it is a lot of work!

Here's a link to my intercooler system on LEF. http://www.thelotusf...nally-finished/

Wayne

[cweeden]

Thanks to everyone who has replied here and via email, all the information is greatly received. I am still a little undecided if I should go ahead over winter with a charge cooler project (sorry Che, I am still erring on the side of charge cooling rather than inter cooling at the moment ) but I will keep you posted if I do go ahead. Either way the engine is coming out to take care of a few other bits and pieces if all goes to plan.

While having all of the projects to learn from does make the whole idea seem much more achievable, the downside is that the standard is very high which adds to the pressure.

I may have a few more questions soon, especially about the thermal calculation or more likely about the results of the calculations already performed.

cheers

-Chris