Intercooler pipes - aluminum vs stainless

[GTS-t VSPEC]

Hi Guys,

I was over at a tuning place the other day and I noticed that they do all of there pipes in aluminum, unless you ask for stainless steel. They said that the aluminum is able to dissipate the heat much more quickly and therefore provides better cooling for racing.

I have stainless and it looks much better, the aluminum welds look shit. Does anyone here run with aluminum pipes and have any experience between it and stainless?

In my current car I will keep the stainless, but I'm planning on building a race car and wondered whether the aluminum might be worth it.

Any thoughts?

See'ya:burnout:

[Guest Boxhead]

it does come down to, bets results with sacrifice of look, or looks with a little sacrifice of power... personally, keep the looks to that car you have now, the pure race car, go for all out power.

[GTS-t VSPEC]

Boxhead,

So you do believe that the aluminum will make a difference in a race car?

The aluminum looks shit but it cools down so much quicker, my pipes take ages to cool down.

See'ya:burnout:

[Doctor]

Get mild and heat coat it. Stainless looks great but heat soak is so bad with it. Aluminium is good but goos luck finiding mandrel bends, but it is super light and doesnt look to bad.

[Guest Boxhead]

gtst - i dont know if its that much better, im just saying that if it is.. i would go that...

i havent done tests etc tho

[GTS-t VSPEC]

Doctor,

That was the thing that I noticed, the bends were absolutly shocking, no smooth airflow characteristic like you want. Mild steel you say, can you get it in 3"and 4" mandrel bends? How much does it weight compared to the stainless.

See'ya:burnout:

[skyzerr33]

similar weight for mild and stainless steel

aluminimun is lighter and disapates heat better but is a bitch to weld and costs more

[GTS-t VSPEC]

Anyone thought about using titanium. I know its light and strong but even the japs do a bodgy welding job on the stuff. With the race car I more concerned about performance rather than looks, but the best of both worlds would be nice, maybe HPC coat the mild steel?

See'ya:burnout:

[Clint32]

Each has its own advantages and dissadvantages, and after using mild steel for a few fittups i decided to use Alloy for my new cars setup to give it a try. I dont think there is any real noticable differece with the temps, and it is a real bitch to work with.

In the furure i will just use mild steel for everything as most people want the job done as cheaply as possible, and if they want to spend a bit extra get them ceramic coated. Stainless i very expensive and getting mild steel pipes coated will be about the same price and should perform better.

[GTS-t VSPEC]

Looks like mild steel is the go then, the aluminum did look crap so I'm glad it's not better.

Thanks for the advice guys.

See'ya:burnout:

[lowlux]

u guys say its a bitch to work with PFFFFT! your not very good welders then, at my last work where we built fuel tankers, and we had some of the best welders ive seen, if your good a tig welding then it should be easy,also its easy to find ally mandrell bends, usually i used to buy them in donuts and cut them down to whatever bend u wanted,u can get them in any size.

If any1 wants any info on where to buy this stuff in Melbourne i can list a few places

[Clint32]

If you know what your doing you can weld alloy v/good, but not many do. It also takes a lot longer than tig welding mild steel, also if you get a small bit of contamination in the metal the whole weld can turn to crap, my pipes loog v/good (check the T04e RB20 thread) but it is harder to work with than stainless or mild steel.

[GTS-t VSPEC]

lowlux,

So you reckon it's possible to do a full 3" intercooler system from aluminum and make it look good? Still the question begs whether it is worth the hassel etc. in terms of performance.

See'ya:burnout:

[red17]

Titanium? Surely it would be the most expensive FMIC in history

Only semi automotive use for titanium ive found so far is sticking slices of it in kneesliders for nice sparks when getting ones knee down on a motorcycle

Ive not seen many ally piping jobs on intercoolers before, im guessing its not too common due to expense rather than practicality.

Red17

[B-Man]

Mine are all 3" aluminium - It looks hot cause it's all polished aluminium - as shiny as SS -

Re Mandrels - They use donuts halves and weld together.

I don't know heaps about it but if I thnink if they use argon , the weld is smooth - no gags and shit.

If you have the one before last HPI - theres an R33 - PRG8RY- check the cooler piping on that - was done by same shop that did mine - looks kewl...

cheers,

[Roy]

Open myself up to assination here, but whats all the fuss with mandrel bends. Now dont all jump down my throat, i know what they are, i work for an engineering company that specialises in pipe fabrication for the Petrochem/pharmaceutical/semiconductor industries.

I think many would be amazed if they put 3" 90deg mandrel bend vs 3" 90deg press bend (done correctly, not the shocking example Nissan gives us on our OE IC piping and exhaust) on a flow bench and measured the difference in flow, or the pressure drop. Yes the mandrel will flow better but i would be amazed if it were more than say 3%. And consider when you would use a 90deg bend, most likely to be using approx 45deg.

Secondly welding aluminium, in its many different grades, is more difficult then say 300 series stainless and mild steels. You need to use a high frequency AC welder (expensive) as opposed to std DC welder, and yes when using TIG is very easy to blow holes thru the tube as the molten metal in the weld pool changes phase very quickly, hence you generally see people using copius amounts of filler wire to avoid this problem, ie more a mechanical joint like soldering then a chemical joint ie proper fusion weld.

And yes they do use Argon when using TIG (Tungsten Inert Gas)in different purities as the shielding gas of the arc, but just as importantly is the purge gas used internally to stop oxidation during welding. These gases can get expensive as they can be mixes of Argon/hydrogen etc.

We have automated welding machines that can weld up to 6" Stainless/titanium etc, but the machine costs over $100,000.00. Thats the price for consistant high quality welds. (immaculate weld bead that requires very little post weld clean up)

You can buy titanium mandrel bends out of the states, which means you dont have to lobster back tube like the japs, meaning less welds, more radiused bend for flow, but the fittings are expensive.

Ideally I, (that is personally), would use HPC coated (or other form of ceramic coating) on mandrel bent aluminium due to its weight advantages. Remember it may dissipate heat quickly but it also absorbs heat quickly. Think of the piping and ic as a heat sink, the slower it takes to cool down, the slower it takes to heat up. And vice versa, the quicker it cools down, the quicker it heats up. HPC coating acts as a thermal barrier so insulates and stops the conduction of heat from tube to air travelling in the tube.

If an extra 1.5kg (estimate of difference between my mild steel HKS IC piping and equiv aluminium plumbing) makes no difference to you, then its likely that the 3% possible flow difference between mandrel and press bend also has little effect on your car.

So for much cheaper purchase cost, fabrication cost you can have your mild steel, press bent piping HPC coated (HPC costs the same whether its aluminium or stainless or mild steel and offered in a variety of colours) doing the same job.

As for stainless, its pretty pricey to buy, has no weight saving over mild steel or aluminium, for cars you dont require its tensile strength or higher burst pressure(approx 40bar for 3"), and its harder then mild steel to cut and weld, and stainless steel can still rust given the right environment.

It can be polished easily, and acts as a larger heat sink, heats up slower, but remember wont dissipate heat as quickly. Im not knocking stainless, or the people using it on their cars, but its almost a matter of having ic piping that will last longer then all other parts of the car.

So each to their own, at the end of the day, my thoughts are that its all semantics. Each has their advantages, disadvantages including cost. Your centre console of crap, loose change & CDS probably weighs as much as the difference between the materials, with the biggest difference being the conduction of heat to the post cooler air. When sitting in traffic they will all be affected by heat soak unless HPC coated/thermal wrapped/ceramic coated etc.

...now ill run and take cover.

[lowlux]

yup i aggree with 100% with what u said, also another thing with mandrell bends is that when u weld them all together with the straights yourve probably caused alot of melted metal inside the joins,and would reduce airflow but with press bends u would have any welding hmmmm i might actually take my pipeing down to get press bent and get it flow tested at my old work to see if theres a difference

[Roy]

Hey lowlux, i hear what your saying, but again i think the slag or excessive penetration, whatever, will again have little effect on flow when you consider the length of pipe, diameter of pipe etc. What do we do about the theoretical turbulence at the silicon hose/hose clamps that will affect flow. Again i think we are talking negligible losses.

Grab a fluids textbook and the calcs will tell you something like 1-2%. But theory goes out the window if you have a controlled test. I would be really interested to hear your results.

For those die hards out there, (me when i win 15 million in Powerball 2nite) there are places that can mandrel bend lengths of tube so that all you need is 2 x1.5 mtr sections of tube, and they can bend those sections to your requirements. We use them for say tube bundles in tube and shell heat exchangers for the navy etc. No welds and nice radius mandrel bends.

I work with a guy that use to fabricate stainless steel road tankers in sunny QLD, can i ask whats the name of the company you use to work for?

[lowlux]

Marshall Lethlean

[Guest MRE]

Bah............humbug.

PVC mate the only way