The_Stig

What intercooler size do i need fore 500 hp...WDH (core size) ? Any suggestions about make and type and size are welcome !

salva

iTrader: (6)

A core with approximately 67 " squared of flow area (Presurrized) for 500 crank HP. For example a 12" High by 5.5" Deep will give you 66"squared. The width can be as long as you have room for, most are about 2' long.

The_Stig

Thanks salva !

Evil Aviator

RETed

I'd get the biggest thing you can afford and fit up front...


-Ted

The_Stig

Money is no object...But the space is. Thats my problem RETed

ikari899

the izuzu NPR small intercooler fits perfectly between the stress bar(that the oil cooler is right below and bolts to) and the upper support that the hood latch bolts in to. it will support 500 whp and they can be found fairly cheap. the best part is they fit PERFECTLY around the radiator, you just need to cut some of the sheet metal out from either side. when that is done it looks like it was supposed to be there its amazing. you just cant have a AC system if you do this

The_Stig

Sounds like a good idea ! But there is 2 typs small and big, whitch one ?

ikari899

your looking for the small one the big one is just taller. so if you wanted you could get the big one and mount it in the same place at some kind of angle. wouldnt be nearly as nice though .

ikari899

https://www.rx7club.com/showthread.php?t=562386

that is the exact one im talking about dont pay more then 100 bucks for one, even that is a little high, i got mine for about 70.

The_Stig

Thanks !

FuseKazuki

big doesnt mean better, it jsut means.. bigger

RE-Amemiya

+1. You should also look into a V-Mount Intercooler.

zjbarra

iTrader: (2)

Alright, this is coming from a mechanical engineer so I've kind of got some idealized fluid dynamics running through my head and I wanted to ask if anyone had some good insight on a few things here:

1. "Frontal area will give you more mass flow thus more capacity to cool, depth will make each square inch of frontal area more effective by allowing it more time to cool." I think this is about right. My question is, is there a non-redneck engineering way I should look at this for how deep one of these cores should be? If you have a very thin but huge front cross section, are the boundry layers within the intercooler so small that frictional loss of your flow is not important? Obviously depth is important here, has anyone ever looked at what the temperature difference between ambient air temperature and after the air has flowed through the intercooler? Is there a point where you’d effectively see less gains by added depth due to the energy absorption capacity of the air being too low?

Added: Wouldn't there be benefits to a larger boundry layer as well? Reduced flow would be a downside but in the same right the slower the charge moves through and the larger the boundry layer, the more cooling effect you should see... This is more relavent to the internal design I suppose than the actual dimensions...

2. End tank geometry: I was on a formula SAE team and when we did our throttle restrictor we were very particular about the angles and the design of our venturi restrictor because the losses in the restrictor are so important to minimize. It seems like all end tanks are just kind of thrown together and all around skanky. A few HKS end tanks look like they are at least somewhat gradual in transition but the HKS intercoolers for the FC are not very large. Has anyone read anything about this that would suggest it is not all that significant? Most intercoolers look like they'd be completely inefficient and have a jetting effect until higher flow rates when the jetting effect would be reduced because the flow across the intercooler near the inlet would be close to the speed of sound and while I'm guessing it wouldn't hit shock, air would eventually work its way across the full cross section, but again, it seems not very efficient.

Generic intercoolers: You can buy intercoolers off ebay for dirt cheap or you can buy them from someone like spearco. Further, you can buy the pre-done packages such as Greddy or HKS. I guess the way I see it, fluid dynamics is a very particular thing and it seems like a lot of people might just buy a cheaper core because they don't think there is a difference. Any thoughts on this? I’d imagine that some effort on the internal designs could go a long way but just wouldn’t be cheap.

ikari899

well from a mechanical engineer to be who is the Powertrain leader of a FSAE team heres what i think

your thinking about the end tanks to much this is not a small engine with a HUGE restriction on it. i dont think all the ports combined in the stock motor have as much crossectional area as a 2.5" dia pipe does (average inlet size for most intercoolers). sooooo you will choke the ports, runners, way before the intercooler. and the losses at the restrictor are due to flow separation and thus turbulence. wellll this is an intercooler, turbulence and lower velocities are a good thing as it will increase the amount of heat lost though the intercooler.

and you dont want a large (laminar) boundary layer you want lots o turbulence or a large turbulent boundary layer, what ever you want to call it, as i said before.

and as far as seeing less and less of gains as things get bigger? of course you will as the 2 masses of air temperatures get closer and closer to each other it takes more and more time to transfer heat between the two.

what it really comes down to is this is not a formula car dont try and treat it like one . i did for awhile and realized it doesnt work like that. you get what fits well into the engine bay. you optimize what you can and call it a day. things like custom intercooler cores will see MINIMAL gains in hp. they have a huge effect is SAE cars because they are only making 50 ft lbs and 80 hp so 1 hp is a much larger percentage then 1 hp in a full sized car. you dont need to squeeze absolutly every thing outa these car's setups.

zjbarra

iTrader: (2)

I'm certainly not worried about choke in the inlet from the turbo. If I choke out a 2.5" pipe, thats a whole new limitation. I'm suggesting that on some of these end tanks that point straight at the intercooler and have absolutely no gradual transition are just promoting jetting. which will shoot straight into the side of the core. Whether this creates a lot of turbulence and helps distribute the flow enough to be effective I don't know, but I could see the jetting and the inertia of this causing the air to not flow through a large portion of the intercooler until the jetting effect starts to cause too much back pressure through at local section of the core which causes it to flow through the rest of the core. Yes its more extreme in a restrictor but I'm more curious if anyone has ever seen something that suggests its virtually not at all important in end tanks. There is some thought that does go into end tanks though as they do have a taper as it approaches the end without the inlet/outlet.

I Think the way I stated it in what I wrote was saying the same thing, I'm just wondering if you get a large laminar boundry layer in a very skinny but tall intercooler passage that a large enough boundry layer might actually cause significant pressure drops or limitations to the flow abilities. This will be where the total cross sectional area of the intercooler relative to the ports going into the engine comes into play and how much loss is seen through these large boundry layers.

But is it significant? Are we seeing an air temperature increase of 10 degrees due to the large amount ambiant air we can flow (obviously dependent on velocity of the car) or are we seeing a 50 degree increase as we flow accross? It will get a reduced amount of heat rejection as the temperature goes but I guess I'm just curious if anyone knows what the average temperature increase is of air that flows through an intercooler is. Obviously this is not a simple answer but I'm just looking for an order of magnitude kind of thing. Is the benefit of the last inch in a 4 inch core 50% of that of the first inch or 95% kind of deal. Quantifying this is not really possible due to the dependence on inlet temperature, ambient temperature and the intercooler used and what not. But like I said, ball park idea and if anyone has read anything to suggest an upper limit of what is beneficial.

To a degree I agree with this. Yes having a really progressive end tank is not going to fit and is going to probably not result in a huge gain but some of these things just look horrible. The laws of fluids are unchanged here compared to FSAE. Its all the same... Yes, things will be different in the sense that we're not worried about a throttle restrictor which makes frictional losses in the intake a very important consideration.

Half of my reason for working on my car is to make it faster, the other half is to apply some of what I learned and see how it works in different applications. This multiplies out on here too. A better intercooler that gets 2 hp on a 80 horsepower formula car compared to a 400hp rx-7 where your core is larger and your flow is larger will see more of an effect. I'm a little bit more curious if this has ever been tested or not. Cost effective enters into it obviously but you might as well do something as good as you can.

If I see something definative that shows the loss in heat rejection for the 4th inch of a 4 inch core is virtually nothing making it damn near 33% more than a 4 inch and there is going to be a noticable difference in heat rejection from the top of a 12" tall core and the bottom where the inlet is, I'll get a 4" deep core that is shorter.

While I do acknowledge a bit of truth to the "its bigger so its not as important" it just seems like it a great way to half *** things and not look at them enough. Thats why I'm curious if there is anything that anyone has read about this, be it an SAE paper or a magazine write up. In the end, most production cars and aftermarket companies would rather build a cheap end tank than a really nice high flowing one that costs 5 times as much, I just want to know if there is any engineering behind this as well or if its just the finance guy being a baby.

ikari899

Hummm well I really don’t have any numbers but im pretty sure if you took some guesses like 160 deg inlet temp and 80 deg air in and guess about a 60-70 lb/min flow rate depending on the application of course and some velocity for the flow though you could rig up some huge equation to see what kinda benefits you will see, But in all honesty I’m WAY to lazy to do that. The only real cost effective way to see the differences is just to do some testing on different end tanks, core depths and buy 4 air temp sensors.

And as far as finance guy vs engineer it seems most cars, in my opinion are built with cost as the first criteria. But in aftermarket stuff it seems like most companies don’t do all that much engineering but more of following engineering rules of tumb

zjbarra

iTrader: (2)

Its been about 2 years since I've touched fluids but here it goes...
E=Q-W+mi(hi+Vi^2)-me(he+Ve^2) should be along the lines of what we're looking for. give you. I think I have the Q and W signs right... Anyways, if you knew the velocity of the air in and the velocity out, and a little bit of work with the ideal gas law and I think you might be able to crank this out. In the end, though, this means nothing until you test it and I certainly don't have the equipment to test this... If I've learned anything from fluids its that its easy to get an answer that looks about right, getting the actual right one requires a whole lot more though.

Agreed! the agenda is a bit different when a 300 dollar end tank is made for several thousand cars instead of say, 100. It is in no way cost effective for anyone which is part of the reason I'm so curious if anything has been done with it. Being an enginerd, I'd be tempted to splurge on sexy engineering for kicks. I'm converting my electrical over to deutsch connectors, completely impractical but amoung the best you can do which is a nice thought.

This whole posting is about whether its always has been done as a rule of thumb and not investigated very well due to the impracticality of the cost or if it was tested and just didn't do anything and so people said F this.

RETed

It does when you're talking about 400hp or more.
It goes doubly do for and FD versus an FC.

BTW, I HATE V-MOUNTS.


-Ted

zjbarra

iTrader: (2)

Why would it matter between a FD and FC making over 400 HP?

Why do you hate V-mounts?

RETed

FD has less frontal area openings versus the FC.
This is stock front bumpers.


It's a fad.
It is a more complex install.
You can search for more threads with my arguments.


-Ted

The_Stig

Try this one www.are.com.au/feat/techtalk/intecoolersMR.htm
This guys know what their talking about !

Speed of light

iTrader: (8)

This is something that has bugged me for years, so I need to say it:

I, too, am an engineer and I am appalled at most of the crap I see in aftermarket. I have a close friend in the industry with a lot of insight into this. And I have personally provided engineering support for some induction and engine development projects. If you were aware of some of the shops, conditions, personnel and ignorance/arrogance involved with the development of many better known products, you would be horrified.

Unfortunately, there are very few real or commissioned engineers working on any aftermarket products; rather you have racers, mechanics and fabricators making adaptations of others' ideas and products for fit, finish, fad and form. Some of it has limited usefulness, most of it is junk. Some of the junk kind of works, but not necessarily well or as advertised. And certainly not as well as the car enthusiast or wana-be racer is led to believe.

You don't really think they care about the details of an IC end tank, let alone correct distribution, do you? It might bug you and me as engineers, but then again, we're the only ones that lose sleep over these things. (LOL)

As for the aftermarket, it is first and foremost all about sales--and those intercoolers, well, if a little is good, more is better and too much is just right.

88IntegraLS

^one prime example is aftermarket intakes which leave an exposed air filter in a hot engine bay. Warm air with its lower oxygen density negates the reduced filter restriction.

Another prime example is huge turbos on small engines...... no point in mashing the gas, waiting, getting passed, and then spooling up.

The_Stig

Yes that`s the true Speed of light ! Everybody that wondering about anything when it comes to intercooling follow this link and read it.
www.are.com.au/feat/techtalk/intecoolersMR.htm
Yes i know their exspencsiv but you get what you pay fore.
Ps: ARE says that endtank designe is half the job, when makeing intercoolers.